# The sound barrier



## Velius (Nov 16, 2007)

An interesting article...

Mach 1 - Who was really the first

According to this article, Hans Guido Mutke claims to have reached Mach 1 during a dive in his Me-262. I started to wonder if any other WWII plane might have been capable of meeting this speed in a dive, particularly the Me-163. I’ve even read an on-line article (which I can’t find at the moment) that the Bachem 349 might have inadvertently broke the sound barrier during it’s first manned flight. Could any propellor aircraft reach Mach 1 in a dive? 

Any comments or thoughts about this? Thanks ya'll! 8)


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## drgondog (Nov 16, 2007)

Velius said:


> An interesting article...
> 
> Mach 1 - Who was really the first
> 
> ...



He didn't, none of them could with Mcrit way too low for all the types in WWII, all fooled by compressibility/calibration issues with airspeed indicators.

IIRC, The Me 262 in particular would start a pitch down at or near critical mach number and, if not corrected immediately would contine the tuck and fail pretty quickly. The horizontal stabilizer was 'blanked' by the ensuing flow separation as the airflow over the subsonic wing design approached transonic velocities (but not the a/c)

No propeller driven a/c was truly close to Mach 1 nor was any ship (jet or rocket or prop) a legitimate .9 Mcrit wing/body combo


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## comiso90 (Nov 16, 2007)

Even if he did, It doesn't take away from Yeager. Level flight is a lot different than a dive.

.


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## Velius (Nov 16, 2007)

drgondog said:


> He didn't, none of them could with Mcrit way too low for all the types in WWII, all fooled by compressibility/calibration issues with airspeed indicators.
> 
> IIRC, The Me 262 in particular would start a pitch down at or near critical mach number and, if not corrected immediately would contine the tuck and fail pretty quickly. The horizontal stabilizer was 'blanked' by the ensuing flow separation as the airflow over the subsonic wing design approached transonic velocities (but not the a/c)
> 
> No propeller driven a/c was truly close to Mach 1 nor was any ship (jet or rocket or prop) a legitimate .9 Mcrit wing/body combo




Not even momentarily during a dive? I know well that no WWII aircraft was capable of supersonic level flight....and even if it did, I know it wasn't staying there for long. But it is not possible at all just to meet terminal Mach??


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## drgondog (Nov 16, 2007)

Velius said:


> Not even momentarily during a dive? I know well that no WWII aircraft was capable of supersonic level flight....and even if it did, I know it wasn't staying there for long. But it is not possible at all just to meet terminal Mach??



No.

None of the WWII designs coupled all the 'lessons learned' into one airframe


swept wings to delay transonic flow 
thin wings for same reason
slab elevators to operate in high compressibility
wing/body design to ensure that elevators were not blanked by wake turbulence

The engines weren't anywhere near powerful enough to brute force the airframe through compressibility and the aircraft were not designed well enough, given that kind of power, to prevent ugly stability and control issues from causing the aircraft to 'depart' and fail structurally in the process.

The F-100A, first supersonic fighter was the last of the US century series fighters designed before Whitcomb collected a lot of prior work into his theory of area rule to address better wing body performance in transonic regions. I'm trying to remember whether the F101 or F102 was designed to embody the area rule

The crafty Crumpp will soon swoop by to give you the 10 reasons I forgot


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## Velius (Nov 16, 2007)

Thanks drgondog!


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## Graeme (Nov 16, 2007)

Interesting site..

Aerospaceweb.org | Ask Us - Me 262 the Sound Barrier


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## Aussie1001 (Nov 17, 2007)

I believe the fastest a prop plane got was 0.83 of the speed of sound, This was in a late model spitfire, apprantly when the plane was pulled out of the dive the engine disconnected itself from the airframe and apprantly the pilot only got out of the dive because he was a big 6 foot 4 inch bloke who had lots of muscle on him otherwise he would have made a coffin of himself 100 foot in the soil... 
I'm not sure if this is true the author of the book was a test pilot during the war and after it.


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## AL Schlageter (Nov 17, 2007)

Not quite correct Aussie.

The Spitfire was a PR XI.

The pilot Martindale landed the Spitfire (EN409) but the reduction gearbox was missing as was the prop. The main engine bearer had buckled.

In PL827 during another test dive the CS unit failed and the SC exploded causing a fire, which went out. He attempted a crash landing but some power lines appeared and while avoiding the lines crashed into a copse of trees. He survived the crash, even retrieving the film despite a damaged spine.


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## delcyros (Nov 17, 2007)

There is scientific evidence, proposed by the technical university of Munich in an study which covers structural integrity of the Me-262 at different dive conditions. It shows that it is theoretically possible to exceed Mach 1.0 under certain conditions in a certain altitude with a certain load (You guess it- everything has to fit to make it through, which in turn makes it unprobable). Something which surprised me.

This study so far was never disprooved. The results of the study were challenged but not on scientific grounds.


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## HoHun (Nov 17, 2007)

Hi Delcyros,

>There is scientific evidence, proposed by the technical university of Munich in an study which covers structural integrity of the Me-262 at different dive conditions. 

Do you perhaps happen to have a link to that study?

Thanks in advance,

Henning (HoHun)


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## Soundbreaker Welch? (Nov 17, 2007)

Aerospaceweb.org | Ask Us - First Supersonic Jet

Here's an article about another pilot George Welch who may have achieved breaking it before Yeager in an XP-86, the prototype of the future F-86 Saber. But if he broke it, it wasn't in level flight like Yeager, it was in a dive. 

But I am biased!


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## Aussie1001 (Nov 18, 2007)

thanks Al wasn't sure, i did however read that the plane that de havilands son died in was supposed to have gone throung the sound barrier. This was in the same book. 

The title is Wings on My Sleeve.


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## AL Schlageter (Nov 18, 2007)

Aussie, that would be the DH108. Sort looked like a Me163.

The Swallow - DH108 crash at Bow Brickhill 1950

_The de Havilland 108 was a swept wing high speed research aircraft built to explore the effects of high speed flight close to the speed of sound. Powered by a de Havilland Goblin jet engine, the aircraft was constructed using a standard de Havilland Vampire fuselage with a newly designed swept back wing at the de Havilland factory at Hatfield. Three aircraft were built for the programme: TG283, TG306 in 1946 and VW120 in 1947.

*TG306* crashed on 27th September 1946 killing the pilot Geoffrey de Havilland during a high speed dive. *TG283* crashed on 1st May 1950 killing the pilot George Genders whilst carrying out stalling trails at Hartley Wintney.

*VW120* crashed on 15 February 1950 at Little Brickhill whilst involved in transonic dive research, killing the pilot Squadron Leader Stuart Muller-Rowland._


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## delcyros (Nov 18, 2007)

HoHun said:


> Hi Delcyros,
> 
> >There is scientific evidence, proposed by the technical university of Munich in an study which covers structural integrity of the Me-262 at different dive conditions.
> 
> ...



Unfortunately not my friend. The study isn´t avaibable online. You might use the KOBV-Fernleihe to see the 1999 paper in question. The below page is from appendix II and shows how narrow to frame for reaching Mach 1.0 is at a pure vertical dive.


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## Soren (Nov 18, 2007)

Going supersonic was definitely possible for the Me-262, however that it did happen and the guy who experienced lived to tell the tale I doubt abit. The Me-262 would be uncontrollable in pitch after 1,100 km/h, so diving to Mach 1 and surviving it would've been a great feat!


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## drgondog (Nov 18, 2007)

delcyros said:


> Unfortunately not my friend. The study isn´t avaibable online. You might use the KOBV-Fernleihe to see the 1999 paper in question. The below page is from appendix II and shows how narrow to frame for reaching Mach 1.0 is at a pure vertical dive.



Does the study suggest how the nose down pitching moment is overcome during transonic shock wave movement? 

I'm on shaky ground here but believe I recalled multiple references to the 262 tucking under in Mcrit dive? IIRC the elevator was blanked in that region of airspeed

Regards,

Bill


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## Soren (Nov 18, 2007)

Above 1,100 km/h the Me-262 would start to pitch down with no means of stopping this, only rudder and aileron control remained.

So kudos to any pilot who survived a Mach 1 ride in the Me-262 !


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## HoHun (Nov 18, 2007)

Hi Delcyros,

>The below page is from appendix II and shows how narrow to frame for reaching Mach 1.0 is at a pure vertical dive.

Thanks a lot! I had seen this single page before, but didn't know it was for a purely vertical dive. So I take it you have read the complete report? I would be interested to know if it only addressed the performance question or if it considered stability and control as well.

Regards,

Henning (HoHun)


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## Hop (Nov 18, 2007)

> Not quite correct Aussie.
> 
> The Spitfire was a PR XI.
> 
> The pilot Martindale landed the Spitfire (EN409) but the reduction gearbox was missing as was the prop. The main engine bearer had buckled.



There's a lot of confusion about the speed the RAE got, and what happened to the Spitfire involved.

The RAE report from January 1944 gave a figure of mach 0.89 obtained in the dive. They thank the pilot, Squadron Leader Tobin, and say the aircraft involved was EN409. They give a chart showing the speeds, g forces etc, which indicates a normal pullout. There is no mention of damage sustained.

Several months later the same Spitfire, EN409, was involved in the incidents you relate whilst flown by Martindale. I haven't seen any reliable record of the speed obtained on those flights.

So EN409 got up to mach 0.89 with no reported damage when flown by Tobin, and suffered problems some months later when flown by Martindale, at an unknown speed.


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## delcyros (Nov 18, 2007)

drgondog said:


> Does the study suggest how the nose down pitching moment is overcome during transonic shock wave movement?
> 
> I'm on shaky ground here but believe I recalled multiple references to the 262 tucking under in Mcrit dive? IIRC the elevator was blanked in that region of airspeed
> 
> ...



The idea behind the study is of more theoretical nature. Following Guido Mutke´s claims in the late 90´s, the TU Munich investigated the possibility. 
The initial dive condition -as far as I understood- was estimated to be very steep, >60 deg. At this condition, the nose down pitch at Mach >.86 would stabilize the -262 at a near or full vertical dive (90 deg) while the negative g-forces generated by the nose down pitch at a lower dive angles would be to excessive and lead to desintegration of the airframe. The steeper the initial dive angle, the higher the probability to stabilize in the vertical after loss of elevator authority due to nose down pitch. Or in other words: If the nose down pitch is small (requiring high dive angles), the airframe may survive. If thenose down pitch is to strong, the negative g-forces would become excessive (finally overmatching 90 deg). Elevator controll is blanked in this speed region but may or may not be restored once the speed of sound is exceeded, according.

Drag is still a considerable problem. Only once full power is applied (at this altitude the generated thrust is more like 500-600 Kp for each turbine @ 100% but weight of the airframe adds another 5-6tons thrust) and vertical dive established the study showed that Mach 1.0 may be approached _temporarely_ at a specific altitude. Once SoS is approached at this altitude, probability is high that a compressor stall cannot be avoided, zeroing out the engines. The technology was not there to prevent this. 
As the plane dives down to lower altitudes (still vertical dive), the drag increases as does the speed of sound due to higher density, resulting in a rapid reduction of the relative mach fraction. It is possible that elevator controll may be restored at in between 3000m and 6000m. 



> Thanks a lot! I had seen this single page before, but didn't know it was for a purely vertical dive. So I take it you have read the complete report? I would be interested to know if it only addressed the performance question or if it considered stability and control as well.



I have read the paper a few years ago. But I admit that I didn´t understood everything due to the very theoretical aspects and methodology. As I underlined above, the study only shows the possibility but concludes that it is well beyond probability that it really happened. Structural Issues (the Verwindungsbruch is mentioned here several times) are taken into consideration. The specific circumstances in the dive entry (low load and max. ceiling at specific speed are good, high load will render recovery in time problmatic), the high initial dive angle and structural issues make it very questionable that a normal -262 will survive the event.

The Me-262 is not a transsonic plane.


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## mad_max (Nov 18, 2007)

One piece of an article I have basically says once past Mach .83 you may live to
tell the tale. In the same article Leutnant Karl "Quax" Schnorrer, Erprobungskommando
262, Kommando Nowotny JG7 says,


> "Beforehand other pilots told me that the 262 is not difficult to fly. But do everything in the climb, not the descent. If you let the aircraft get into a dive and the speed rose over 1,000km/h (620 mph), you might not get it out of the dive."



FWIW


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## Velius (Nov 23, 2007)

I keep reading in certain articles (I am however skeptical due to lack of decent sources; I'm just bringing this out on the floor) that the BA 349 might have inadvertantley broke the sound barrier during it's first manned flight. Some suggest that it MIGHT have been able to exceed Mcrit due to it's near 1:1 thrust to weight ratio. I know this doesn't necessarily mean speed of sound; but what does everyone think?


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## drgondog (Nov 23, 2007)

Velius said:


> I keep reading in certain articles (I am however skeptical due to lack of decent sources; I'm just bringing this out on the floor) that the BA 349 might have inadvertantley broke the sound barrier during it's first manned flight. Some suggest that it MIGHT have been able to exceed Mcrit due to it's near 1:1 thrust to weight ratio. I know this doesn't necessarily mean speed of sound; but what does everyone think?



Critical mach number is that flight profile which results in transonic flow over the airfoil in which a shock wave first forms.. frequent side effects are flow separation and movement of center of lift aft - both bad things if elevators are rendered ineffective.


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## delcyros (Nov 23, 2007)

I too have serious concerns about Bachem claims. While much is possible in conditions of accidents, I cannot imagine how the Bachem airframe, structurally made entirely from wood will survive the stress imposed by flying high Mach fractions. I know that the Bachem dataset was composed from wind tunnel tests made at Braunschweig and Berlin, dating to january, 30th, 1945. None of those tests allows any conclusion from a pure drag point of view, which could support the claim. The manned start of BP-20 M23, dating to 1st of march 1945 lasted only 50 seconds. It is not reasonable how the plane could lift off, accelerate, turn and dive with reaching the speed of sound in such a short timeframe.


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## renrich (Nov 23, 2007)

There was an interesting film called "Breaking the Sound Barrier" that showed a Spitfire diving into compressibility in the first scene and later a British jet by the name of Prometheus ( I can't remember what actual AC it was) broke the sound barrier in a dive. I remember the dialogue of the pilot screaming, "nose heavy, trimming back." It was a British film and quite good.


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## Graeme (Nov 24, 2007)

renrich said:


> a British jet by the name of Prometheus ( I can't remember what actual AC it was)



The Supermarine 535. Forerunner of the Swift.


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## delcyros (Nov 24, 2007)

It´s a BEAUTY!


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## renrich (Nov 24, 2007)

Thank you Graeme, that is it. It was agood looking AC. Was it kin to the Supermarine Attacker?


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## Graeme (Nov 25, 2007)

renrich said:


> Was it kin to the Supermarine Attacker?



Yes. The lineage starts off with a swept wing version of the Attacker, the Supermarine 510, then the 528, the 535 and then the 541 or Swift as it became known.

The Supermarine 510 had a couple of 'firsts' in its career. It was the first British jet-powered aircraft to fly with sweepback on the wings and tailplane. It was also the first swept wing aircraft in the world to land and take-off from an aircraft carrier. . however it required assistance from rockets to take off.

It now resides at the Duxford museum.


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## Elvis (Nov 25, 2007)

drgondog said:


> No.
> 
> None of the WWII designs coupled all the 'lessons learned' into one airframe
> 
> ...


Area rule was what pinched the middle of the F-102 and got it renamed the F-106.
You've got the 102, 104 and 105 in production before that happens.
How can the F-100 be the last of the century fighters built before Area Rule became known?

As for WWII aircraft reaching the speed of sound, its said that many a pilot either died or almost died because they lost control of their airplanes in a steep, fast dive.
I don't think any plane in WWII actually broke the sound barrier, but I believe many came very close. At least up to .9 mach, as there are many stories of pilots reaching 700MPH in a dive (seems mostly from P-38 pilots).

...but you also mentioned how compressability "fooled" the a/s indicators.
Could you please explain that in more detail?
I am curious how that situation could exist and what did NASA (NACA) do to modify the a/s indicator on "Glamourous Glennis" so that it would read corrrectly?






Elvis


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## renrich (Nov 26, 2007)

One of the best diving fighters for the US was the P47 and it's dive limit was .82 mach and at that number it was well into compressibility. As you know, the speed of sound varies only with air temperature so the further you dive which equates to more speed, the faster you have to go to reach a higher mach number. I strongly doubt any ww2 piston fighter ever reached .90 mach.


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## kool kitty89 (Dec 8, 2007)

Do you have to have a slab, all-moving, all-flying, variable incedence, or fully-trimmable tail to maintain elevator control at transsonic speed?

From what I read on the F-86, the E model was the first to use the all-flying tail, so earlier models must have had a normal elevator combined with a fully-trimmable tail. So Welch would have had to use trim to maintain controll in the XP-86.

The F-94C was also able to dive through mach 1.0 as was the CF-100, so they must have trimmable tails too. (One interesting note is that the 1946 Su-9,11 had a variable incedence tailplane among its inovations)

So this would also mean the Me-262 HG-III would need a variable-incedence tail to function as planned.

Personaly I think Welch's acheivement is more impressive than Yeager's as the Saber was able to takeoff and land under its own power and used an air-breathing powerplant. (not to mention it was a combat craft) The XP-86's sonic boom (the second one done less than 1 hour prior to Yeager's) shattered windows miles away, while Yeager's was mugh more subdued, more like thunder. (which, of course, is a sonic boom)
The Miles M.52 would hav been more impresive to see than the X-1, had it been completed. (plus it used Whittles reverse-flow W.2/700 albeit with reheat)

see: The Amazing George Welch: Part two


While possible that the Me 262 broke the sound barrier and survived it, the pilot's story could just as easily be explained as approaching mach .9+ and then regaining control in denser air.

The weirder part is what the US test pilot's handbook supposedly said in these cases. The US pilots clearly didn't exceed the speed of sound, what they seem to have experienced is exceeding .86 mach and regaining control at lower altitude. 

from: The Story of my First Supcrsonic Flight on 9 April 1945 over Innsbruck


> This report describes the experiences of a pilot in breaking through the sound barrier with an aircraft Me 262 which was designed for subsonic flight. The main characteristics of crossing the sound barrier in such an aircraft can be summarised as:
> 
> Firstly extreme buffeting and vibration
> Followed by a short period in which the control surfaces are totally ineffective
> ...



Also, prop driven (at least mixed-powered) a/c have broken the sound barrier. 

From wikipedia.org


> McDonnell proposed a naval version of the XF-88, a two-seat operational trainer, and a reconnaissance variant, but none were built. The first prototype was modified to XF-88B standard, with a nose-mounted turboprop engine added to the two existing turbojets. This was used for flight testing through 1956, and achieved speeds slightly exceeding Mach 1.0,[2], the first propeller-driven aircraft to do so. Both prototypes were scrapped by 1958.


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## drgondog (Dec 8, 2007)

Elvis said:


> Area rule was what pinched the middle of the F-102 and got it renamed the F-106.
> You've got the 102, 104 and 105 in production before that happens.
> How can the F-100 be the last of the century fighters built before Area Rule became known?
> 
> ...



In Incompressible flow there is no assumed change in density as a function of velocity nor are temperature effects below transonic flows important. So velocity readings from stagnation pressure would yield a pretty accurate velocity... whic assumes constant density and no temp change.

But in compressibility regions, reading simple stagnation pressure goes out the window as both density and temperature changes as a function of velocity. 

None of the instruments in WWII made any corrections for compressibility.

I do not know what Glamorous Glennis used instrumentation wise.


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## kool kitty89 (Dec 8, 2007)

Also, even in the later 1940's publication movie, the narrator says "the first time in level flight" and "for the first time, except in dives" obviously implying the actions of the XP-86. Though the Sabre's feats were never officially accepted, they've never been denied officially either. There also were 2 sonic booms to to substanciate Welch's 2 dives.

While Delcyros showed that it is technically possible for the Me-262 to survive Mach-1, its hard to proove that it was done. Plus no sonic booms were noted, though these may have been confused with explosions from the crashing 262 that the Mustang had shot down. And it was war so such sounds would not be as closely scrutinized I guess.


Is it true that conventional Elevators will regain control once the sound barrier is broken? Or is this incorect.

And I still dont know about: Do you have to have a slab, all-moving, all-flying, variable incedence, or fully-trimmable tail to maintain elevator control at transsonic speed?

From what I read on the F-86, the E model was the first to use the all-flying tail, so earlier models must have had a normal elevator combined with a fully-trimmable tail. So Welch would have had to use trim to maintain controll in the XP-86.

The F-94C was also able to dive through mach 1.0 as was the CF-100, so they must have trimmable tails too. (One interesting note is that the 1946 Su-9,11 had a variable incedence tailplane among its inovations)



I wonder if it would have been possible for the P-80 to do so too... (if any it would have been the more-powerful C model with 5,400 lbf with W/M injection)


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## HoHun (Dec 9, 2007)

Hi Kitty,

>So this would also mean the Me-262 HG-III would need a variable-incedence tail to function as planned.

The Me 262 actually had a variable incidence tail that was moved for trim.

Regarding the resulting control forces, here is an interesting comment by Eric Brown (from Flight Journal Special Winter 2000): 

"In the dives from 30,000 ft, the nose started to drop at Mach 0.83 and a 30-pounds pull was required to maintain the 25-degree dive angle. As the Mach number increased a violent buffeting set in, and the aircraft became progressively nose-heavy, so a pull force of about 100 pounds was necessary at Mach 0.86 to keep the dive angle constant."

His dives were carefully prepared in order to measure the maximum possible Mach for the Me 262, including carefully pre-setting the optimum dive trim on the ground.

Regards,

Henning (HoHun)


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## kool kitty89 (Dec 9, 2007)

I was just wondering if conventional control surfaces (elevators) work once the barrier is broken. (as has been suggested several times)

Otherwise all a/c that use conventional elevators and have broken the sound barrier in dives must have had trimmable tails to maintain controll. (ie pre-E model Sabres, F-94C starfire, CF-100, possibly Me 262) But welch makes no mention of trimming durring his flights, so did the XP-86 have an all-flying tail?

Technically the X-1 could have broken the sound barrier much sooner, utilizing dives, but it still wasn't able to take-off on its own, and wasn't air-brething. Plus it seems the AAF took-over the project from Bell, so a millitary officer would be the first to acheive it. The Miles M.52 would have probably beaten both of them though IMHO. (at least in dives)


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## davparlr (Dec 9, 2007)

Elvis said:


> Area rule was what pinched the middle of the F-102 and got it renamed the F-106.
> You've got the 102, 104 and 105 in production before that happens.
> How can the F-100 be the last of the century fighters built before Area Rule became known?
> 
> Elvis



This is incorrect. Even before the YF-102 first flight, it was known that it was likely that it was incapable of going through the sound barrier. Four YF-102A were constructed implementing the "area rule" with longer nose, pinched in waste and added fairings to the tail section. The YF-102A succeeded in breaking the sound barrier. The F-106 was an entirely different bird. All the other aircraft you mentioned came after the "area rule" was implemented on the F-102A and all have "area rule" incorporate in their design.


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## davparlr (Dec 9, 2007)

It is hightly unlikely that any pilot, in this era, could accurately report passing Mach 1 without an aircraft properly instrumented to detect Mach 1 flight.


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## magnocain (Dec 10, 2007)

Perhaps if someone rode in a Grand Slam with a little motor hooked up to it...that would break the sound barrier.


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## davparlr (Dec 10, 2007)

> drgondog=Good catch. You are right about the 102. I was disconnected there because it was first applied to 102 design (after flight test) because of dramatic difference in actual performance with 102 body versus predicted performance. The F106 was the first production ship using whitcomb area rule.
> 
> Whitcomb first tested the 'area rule' in a NACA wind tunnel in 1952. By the time of his eureka the 100 was in production and the 102 had not flown yet but was in advanced design. The first flight of the 102 was in late 1953 and by that time the F-104 design was nearly finished - ditto F-105 so they were too late to fix



Area rule is apparent on the F-105 as seen by the swelling of the fuselage aft of the wing (no, this is not because of the engine size). It is less apparent on the F-104, but sources have indicated it was designed to area rule requirements.


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## drgondog (Dec 10, 2007)

davparlr said:


> Area rule is apparent on the F-105 as seen by the swelling of the fuselage aft of the wing (no, this is not because of the engine size). It is less apparent on the F-104, but sources have indicated it was designed to area rule requirements.



Dave - area rule for certain was applied to F-105, but it was a re-design after initial flight tests and after a review of the modified YF102 test results.

I was wrong about all Century series post F-100. 

I have not seen a positive unequivocal reference to F-104 employing area rule and the first mock up was only months after Whitcomb posted his papers on the area rule wind tunnel results. It would be easy to suspect the 104 did not have benefit of original design input, nor do I see any reference to disappointing flight test results like the F-102 and F-105.

Here is what I believe - prototype YF-102 - no area rule
Four YF-102 allocated to re-design of fuselage for test purposes incorporating area rule. YF-102B was production ready use of area rule but further modified to become YF-106 which used those results in initial design and subsequent production.

F102A - area rule

F-104 prototype finished and F-104 flight test started before modified YF-102's take flight. Don't see any reference to F-104 area rule and I can't see it with Mk I eyeball - doesn't mean it ain't there I just can't say it is.

F-105 Contract let and mock up produced before first flight of YF-104 and second series of YF-102A test flights demonstrating poor results.. so design work well on way before realizing that area rule might be required.

YF-102A in meantime is modified from YF102, has area rule and leads to design of YF-102B which in turn is re-designated F-106 because of Area rule, change in inlet config and longer nose.. but F-102A continues production w/o these mods.

F-105 flies in Oct 1955, terrible results, re-designed using area rule, most tooling scrapped but the first production F105A emeges in 1958 with area rule.

YF-106 first flies in Dec 1956 as first Century series fighter 'designed' from beginning w/area rule even though it is a derivative of F-102B.

This is best I can do - fire away

Regards,

Bill


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## kool kitty89 (Dec 10, 2007)

The F-100 went supersonic in level flight as a non-area-rule craft. And a sonic boom is a pretty good identifier of breaking the barrier. (as seen with Welch's flights)


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## davparlr (Dec 11, 2007)

drgondog said:


> Dave - area rule for certain was applied to F-105, but it was a re-design after initial flight tests and after a review of the modified YF102 test results.
> 
> I was wrong about all Century series post F-100.
> 
> ...




This is all basically confusing when discussing test aircraft and your statements are all true. However, the F-100 or F-101 (I can't find anything about area rule on the F-101) were the last AF fighters without area rule. The F-102A, F-104 (see NASA quote below), F-105, and F-106 were all area rule aircraft as delivered to the AF.

The following quote are from the NASA website "http://history.nasa.gov/SP-4305/ch11.htm"



> Convair faced up to the problem, and so did Chance Vought (which redesigned its F-8U carrier-based interceptor according to the area rule), Grumman, and eventually Lockheed (in April 1956, its area-rule-based F-104 Starfighter was the first jet to exceed Mach 2 in level flight).


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## drgondog (Dec 11, 2007)

davparlr said:


> This is all basically confusing when discussing test aircraft and your statements are all true. However, the F-100 or F-101 (I can't find anything about area rule on the F-101) were the last AF fighters without area rule. The F-102A, F-104 (see NASA quote below), F-105, and F-106 were all area rule aircraft as delivered to the AF.
> 
> The following quote are from the NASA website "http://history.nasa.gov/SP-4305/ch11.htm"



Dave - I don't doubt the quote but it's awfully hard to see any pinch on 104 - especially from below.


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## Crumpp (Dec 11, 2007)

As Bill points out, the measurement of velocity in the transonic realm was problematic in the late 1940's. 

All power producer subsonic designs will have a very similar mach limit. The fact they have a propeller puts them in the same range for mach limits.

I calculated out Mutke's claims and under the conditions he states there is no doubt that he would have exceeded mach 1 IMHO.

However I highly doubt the conditions where as he stated. First his airspeed indicator is going to be very inaccurate in the transonic realm. 

Secondly but most importantly, he would be exceeding the q-limits of the airframe. The q-limits for the Me-262 were in the vicinity of mach .8, well below mach 1.

The airframe simply cannot go that fast without turning itself into confetti. Could Mutke's airframe have been a fluke? Highly unlikely and just about requires a pointy tin foil hat to be worn.

Now this does not mean that everything in the cockpit and the behavior of the aircraft did not lead Mutke, who was not an engineer, to very reasonably conclude he exceeded the speed of sound. 

All the best,

Crumpp


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## kool kitty89 (Dec 11, 2007)

Also, the non-area-ruled Convair XF-92, the first delta wing fighter, (and the first powered delta a/c to fly iirc, first in early 1948 for the experimental proof-of-concept craft) and the forerunner to the F-102 and F-106 was able to easily dive through Mach 1, even (albeit not as well) with it's original lower-powered J33 (5,200 lbf), and could almost sustain Mach 1.0+ after leveling out with the 7,500 lbf and later 8,400 afterburning J33. (providing a .5-.6 thrust/weight)

Also, the Skyray, which flew in 1951, well before the YF-100, was capable of exceeding Mach 1.0 in level flight, albeit not at SL, and didn't do so until after the F-100 had iirc, but the Skyray also held the world speed record over the Super Sabre for a time.

And actualy, Delcyros showed that, in verticle dives there is far les stress on the airframe, particularly the wings (as there is far lower wing loading on the lift surface), and that if a ~60 degree or steeper dive were attempted, it is possible to dive the 262 through Mach 1.0 from high altitude, albeit the window for conditions to allow this is fairly small. The airframe could survive, with some warping and only if trim was used to maintain control.

The F-84 could have probably dived through mach 1 had it used thin, low drag wings, as the fusalage mach limit was very high, though still trim would be needed to maintain control. The thick wings were a heavily limiting factor on the plane as exceeding Mach .80 at SL would result in violent pitch-up and if this was maintained, the airframe tended to desitegrate. (though on at least one occasion an F-84G did this intentionally to escape 2 Migs on his tail, one actualy crashed, while the F-84 survived with heavy warping to the wings) At higher altitude, exceeding mach .8 resulted in heavy buffetting. 
The very clean airframe, despite the thick wings, can be seen in that The XP-84 was capable of 592 mph at sea level with only 3750 lbf (less thrust than the early P-80A) at a heavy weight of ~16,000 lbs. (thrust/weight of ~.23 and even lower on some later models, at MTO, except for the D and G, and even then <.25 @ MTO, due to weight increasing more than thrust)

The (wet) wings though, allowed for a 1,300 mi range on internal fuel only and a max range of 2000 mi with the F-84G with a top-speed of 622 mph at SL. So a thin wing would have been useful for a shorter ranged craft, but not for escort and should have made an excelent intereceptor. Even such a re-winged version should have ~1300 mi range with droptanks, better than the Sabre, and would still have some escort capabillities. Speed would probably increased to ~620 mph at altitude and 650+ at SL.


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## davparlr (Dec 12, 2007)

drgondog said:


> Dave - I don't doubt the quote but it's awfully hard to see any pinch on 104 - especially from below.



I whole heartedly agree but the cross sectional area of those little razor blade wings would be VERY small so the fuselage corrections would also be very small and probably difficult to detect. Any info on the F-101?

In pilot training, we had a student from Afghanistan who was terrible but since this dad was the chief of the Afghanistan AF, he was basically ordained to complete the course. It took him two years to finish a one year course. After graduation he went on to fly F-104s. He is probably dead.


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## drgondog (Dec 12, 2007)

davparlr said:


> I whole heartedly agree but the cross sectional area of those little razor blade wings would be VERY small so the fuselage corrections would also be very small and probably difficult to detect. Any info on the F-101?
> 
> In pilot training, we had a student from Afghanistan who was terrible but since this dad was the chief of the Afghanistan AF, he was basically ordained to complete the course. It took him two years to finish a one year course. After graduation he went on to fly F-104s. He is probably dead.



Dave - I agree that if the 104 had area rule design it would be tough to spot and no,even on the usual on-line references on the 101, I can't find any discussion on area rule. It's first flight was in same year as F-104


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## kool kitty89 (Apr 18, 2008)

It was mentioned earlier that slab elevators, all-flying tail, all-moving tailplane, stabilators were require to maintain controll in the trans-sonic region and to maintain control past Mach 1.0. Or short of this, requiring a fully trimmable/variable incidance tailplane to recover from a supersonic dive. (which the Me 262 had, and the early F-86)



drgondog said:


> No.
> 
> None of the WWII designs coupled all the 'lessons learned' into one airframe
> 
> ...




I know some of this had already been dealt with and Delcyros listed the study showing it was possible for the 262 in the right conditions. And, though stick forces would have been to heavy to recover with, trimming the tailplane would work.

I finally found an answer to my earlier question about normal elevators' effectiveness in the trans-sonic region and at Mach 1.0+ and their functionallity. The first thing that made me question this is that the XP-86 and early production F-86's used a normal elevator with a fully trimmable tailplane, but from pilot accounts (and Welch's notes) trimming the tailplane to recover from supersonic dives is not mentioned.
When nearing Mach 1 a shockwave will develop on the tailplane which will become increasingly strong as speed increases, making the the stick forces for the elevator very high and eventually useless. Hence why this cannot be used for the 262.
Then I read a little more into the XP-86/F-86 anf found out tha while they still used conventional elivator system but with hydrolicly boosted controls which allowed much more force to be applied than a pilot is capable of with manual controls. Thus, while the elevator controls still become less responsive at trans-sonic speeds they will still function.


And also there have been a number of straight winged fighters capable of controlled supersonic dives. They include the F-94C Starfire, CF-100 Canuck and a couple others. (all being all-weather interceptors iirc)


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## SoD Stitch (Apr 19, 2008)

drgondog said:


> Dave - I agree that if the 104 had area rule design it would be tough to spot and no,even on the usual on-line references on the 101, I can't find any discussion on area rule. It's first flight was in same year as F-104



AFAIK, the first aircraft to have the "area rule" applied to it was the F-102, and only after it failed to achieve supersonic speeds in level flight; after the fuselage was given the "area rule" treatment, it achieved Mach 1+ with no problem, even on the under-powered J-57.


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## samd (Oct 6, 2008)

My G-pa claimed that they had a P-47 in the South Pacific that he swore broke the sound barrier in a dive. It appears there are a number of technical issues that makes this seem impossible. He was awfully sure of this claim and he was very a intelligent engineer and understood what it meant to accomplish this. He clearly spoke of the mechanical limitations of the aircraft and he still smiled and said "we did it long before everyone else!" What could the explanation be? Did the pilot get an inaccurate airspeed reading? Was he just trying to impress the grandkids?


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## Soren (Oct 7, 2008)

Well, if any a/c could have done it in WW2 it would've been the Me-262, and recent aerodynamic studies made in Germany have confirmed that it is perfectly possible that it did as the airframe was capable of it. I personally believe that it could. Another a/c which is also claimed to have broken the sound barrier before Yeager is the F-86 Sabre, and there is no doubt about this one IMO cause I don't see a single reason for why it shouldn't be capable of it. Still there are people who insist Yeager was the first, which I believe is bullcrap really.

As for the P-47, no chance, the propeller wouldn't allow it along with the larger frontal area.


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## FLYBOYJ (Oct 7, 2008)

The F-86 was capable of breaking the sound barrier with ease and did so on many occasions including during its initial flight testing. We had the thread about George Welch who allegedly did it just prior to Yeager’s flight just to piss him off, and that event was witnesses by many people who heard the sonic boom.

Yeager's flight will alwasy be recognized as the first because of the actual telemetry tracking and witnesses on hand - it was an "official" event.


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## Waynos (Oct 7, 2008)

The highest recorded speed achieved by a piston engined aircraft was mach 0.94 in an 84 Sqn Spitfire F.22 over Hong Kong in 1954 just prior to the Spit's final retirement from the RAF.

It was concluded in a series of RAE tests during, and immediately after the war that the Spitfire was the fastest diving aircraft of WW2, including jets, due to its extremely thin wings which were the thinnest on any production fighter and delayed the onset of drag sufficiently for the Spit to pull ahead in a dive against *anything* else.

There are various references to this research in several books, one of the them is the Putnam volume on Supermarine aircraft and another is Jonathan Glancy's biography of the Spitfire. A quote from one of the test pilots which I love was "we flew everything from Spits and P-51's to the newest jets, our own and the Germans, our job was to dive as hard and as fast as we could and then fire the guns to see if the wings came off".

Nice job!

I also have a book (Buttler - German Secret Projects) that attests to RAE findings that the Me 262 and 163 were aerodynamically and structurally incapable of exceeding m 0.86 being confirmed by Willy Messerschmitt himself who said that this was never a consideration in their design and if it had been both aircraft would have looked very different.


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## pbfoot (Oct 7, 2008)

FLYBOYJ said:


> The F-86 was capable of breaking the sound barrier with ease and did so on many occasions including during its initial flight testing. We had the thread about George Welch who allegedly did it just prior to Yeager’s flight just to piss him off, and that event was witnesses by many people who heard the sonic boom.
> 
> Yeager's flight will alwasy be recognized as the first because of the actual telemetry tracking and witnesses on hand - it was an "official" event.


It was standard training for all the Sabre drivers to bust mach and with a little search on google came up with this
F-86 Sabre Mach Busters Club card, issued by North American Aviation


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## Waynos (Oct 7, 2008)

I also found this photo of Sqn Ldr Martindales aircraft following the mach 0.89 dive;


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## HoHun (Oct 7, 2008)

Hi Samd,

>What could the explanation be? Did the pilot get an inaccurate airspeed reading? Was he just trying to impress the grandkids?

There are several factors that tend to exaggerate the speed reading, one of them being the speed indicator's inability to account for compressibility effects. Another aspect is that to get your true airspeed, you'll have to correlate indicated air speed and altitude, and the altimeter had errors of its own, especially at high speeds and during rapid altitude changes. You also need to keep track of the exact temperature - everthing combined, it's quite difficult to reliably track the data if no recording device of some kind is used.

I'm sure your grandfather honestly considered his speed figures accurate, as many other people associated with high speed dives during WW2 believed too that they had achieved speeds that - as we know from hindsight - were unrealistic for the aircraft type in question.

High-speed dive tests were at the leading edge of scientific progress in these days, and I think it's quite credible that people with good education but no access to the latest research results would tend to over-estimate speed readings despite striving for the best possible accuracy. This was not an uncommon experience - you'll find similar stories for several aircraft types, both by Allied and Luftwaffe personnel.

Regards,

Henning (HoHun)


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## kool kitty89 (Oct 7, 2008)

Waynos said:


> The highest recorded speed achieved by a piston engined aircraft was mach 0.94 in an 84 Sqn Spitfire F.22 over Hong Kong in 1954 just prior to the Spit's final retirement from the RAF.
> 
> It was concluded in a series of RAE tests during, and immediately after the war that the Spitfire was the fastest diving aircraft of WW2, including jets, due to its extremely thin wings which were the thinnest on any production fighter and delayed the onset of drag sufficiently for the Spit to pull ahead in a dive against *anything* else.
> 
> ...




I've read this about the Spitfire before, and it bothered me as (using high-speed a/c with similar wing thickness as comparisons) those Mach values should be well over the Spitfire's critical Mach number. (~.80-.82 going by the P-80, Meteor, and P/F-84) So either the data is wrong, or the Spitfire's elevator remains effective above critical Mach.


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## kool kitty89 (Oct 7, 2008)

http://www.ww2aircraft.net/forum/aviation/ww2-fighter-critical-mach-speed-802.html

Actually It seems the Spitfire didn't have any pitch control ability (except maybe trim) at these high Mach numbers, though maybe it didn't suffer the same pitch-down problems as many others at Critical Mach. (like the Me 262, aileron control remained due to the thinner outer wing)


also see: The Incomplete Guide to Airfoil Usage
for airfoil info


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## Soren (Oct 8, 2008)

It has been solidly confirmed by studies done in Germany that the Me-262 was perfectly capable of breaking the soundbarrier. 

The problem which could occur was as KK describes if the pilot failed to stop the negative G the a/c automatically started to generate above .86+ Mach by trimming the tailplane.


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## kool kitty89 (Oct 8, 2008)

Delcyros refrenced the article on the first 2 pages of this thread.

Besides the -G loading issue, there are a couple other factors that have to be right for the Me 262 to survive the event.

The load has to be right (too allow recovery in time), the dive angle has to be steep (both to accelerate fast enough and to minimise pitch-down stability problems), and finally the starting altitude has to be right. (near the ceiling for medium load) 
See the graph on pg.1 as well. (the study was for vertical dives)

If Mach 1 is reached the engines will stall and with the reduction in thrust as well as the rapidly increasing air density as well as the increasing local speed, the a/c will quickly drop to below critical Mach and regain elevator authority for recovery. (though if the tailplane is already retrimmed to counter the pitch-down, when speed drops below ~.86 mach the a/c will already want to pich up with neutral elevator)


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## Soren (Oct 8, 2008)

Regarding the discussion link you provided earlier: It is completely incorrect that the Me-262's airframe couldn't sustain the stress of a Mach 1 dive, as proven in studies done in Germany in 1999. That needs to be made clear.

That it would be a problem to reach Mach 1 is another issue, one which I agree with.


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## Waynos (Oct 8, 2008)

You guys are way ahead of me on the techspec side of things so I'm not going to argue but I just wanted to add that according to Glancy's book the Spitfires wing was not designed to any naca aerofoil section but was thinner than the recommended ratio, which led to doubts about its strength in the early days but was obviously later found to be perfectly ok and this is what gave it its advantage in a dive. I never said that 0,94 was achieved in a dive did I? Hopefully that part was obvious. sorry.

Also the P-84 was not part of the trials so I can't comment on that one but the P-80 was, as were the Vampire, Meteor, GA2 and Attacker (laminar wing) as also was the Spiteful (same wing) and it was a surprise that the Spitfire was still the fastest in the Dive. This was far from bragging for Supermarine, it was actually a bit embarrassing.

I'm not sure how accurate the 1999 tests for the Me 262 were (I don't know anything about them) but the 1945-46 tests were carried out with actual airframes not mathematical extrapolations and the fact that Messerschmitt supported the findings kind of convinces me, no offense as you clearly know your stuff.

Regarding the Messerschmitts 'looking different', who knows? Maybe he was thinking along the lines of the HG.III and P.1110? (just guessing there)


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## kool kitty89 (Oct 8, 2008)

What the Messerschmitt tests showed (similer to the British tests) was that elevator control was lost at Mach ~.86 and a strong pitch down behavior devloped. (trim changes were not mentioned in corelation with this in anything I've read)

The lower the dive angle the greater the chance of -G damage from pitching down. (and controling the pitch down with trim may be more difficult as well)

Vertical dives give the best chances, as the greatest net trust is avialable (the a/c's total weight) and the faster the a/c can accelerate, the shorter time spent in the region between Mach .86 and 1.0. (the longer time spent in the "conmpressibility region" the greater chance of structural damage or failure from buffetting)


The key factor in Mutke's story is that while still accelerating durring strong buffetting, there was a breif period of calm where control was apparently restored. (which is characteristic of exceeding Mach 1, though elevator control may or may not work in this region of flight -I don't know the specifics behind this)


In any case, buffeting damage on Mutke's a/c was quite severe, with considerable warping of the wings and missing rivets. (resulting in a difficult landing and the a/c subsequently being scrapped iirc)



Everything I've seeen on data of the Spitfire's airfoil is that it's a conventional NACA 2200 series airfoil (in fairly common use at the time) with a root thickness of 13%, this would still have made it the thinnest wing on any production a/c (let alone fighter) up until the introduction of the first jets. And it very well could have had the highest critical mach number (and terminal diving speed) of any piston engined fighter.

But I'd think that the .89 dive speed figure would be a terminal dive (well past critical mach) and elevator control would be lost. (though that doesn't mean recovery would be impossible)



Another note, is that the flight manual from US testing of the Me 262 at Wright Field in 1946 mentiones similar behavior in terminal dives as in Mutke's case.


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## davparlr (Oct 8, 2008)

kool kitty89 said:


> If Mach 1 is reached the engines will stall and with the reduction in thrust as well as the rapidly increasing air density as well as the increasing local speed, the a/c will quickly drop to below critical Mach and regain elevator authority for recovery. (though if the tailplane is already retrimmed to counter the pitch-down, when speed drops below ~.86 mach the a/c will already want to pich up with neutral elevator)



Good point. On looking at drawing of the Jumo engine, it appears that the inlet is a convergent inlet. If so, the airflow will go supersonic before the aircaft, especially at the compressor blades, causing shock waves and airflow disruption. In order to determine whether the Me-262 could penetrate the sound barrier, an inlet analysis must be made to determine airflow characteristics.


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## kool kitty89 (Oct 9, 2008)

Delcyros already mention the compressor stall issues on pg.2 of this thread. (this penomenon was unavoidable in this configuration -fitting a lengthened intake with a shock cone may have prevented it though)

But, in a vertical dive and at full power the engines will only be generating ~20% of the total thrust. (the rest coming from the a/c's weight) And the engines wouldn't stall until a shock wave develops at the intakes. (at or very very close to Mach 1)


I also forgot to add that, while Mutke's discription is a fairly good indicator that he may have indeed reached Mach 1, unfortunately the best proof of breaking the soud barrier would probably not have been noted in this case, a sonic boom. If he did indeed exceed Mach 1, the boom could have simply been contributed to a crash or an explosion as it was an unknown phenomenon. (likewise when George Welch first dove through the Barrier, nearby civilians who heard the boom expected it to be a crash. But it's this that gives the best proof for Welch's claim -allong with corisponding flight notes from Welch)


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## Soren (Oct 13, 2008)

Waynos,

Let's get something clear here, the 1945-46 tests didn't establish that airframe couldn't take the stresses of a Mach 1 dive, all they did was conclude that at above Mach 0.86 elevator control was lost. Remember these weren't straight down vertical dives.


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## drgondog (Oct 13, 2008)

Soren said:


> Waynos,
> 
> Let's get something clear here, the 1945-46 tests didn't establish that airframe couldn't take the stresses of a Mach 1 dive, all they did was conclude that at above Mach 0.86 elevator control was lost. Remember these weren't straight down vertical dives.



Right or wrong, all the reports I have seen regarding the 262 in dives - discusses the pitch down characteristics around .82-.86 M, apparently due to the elevator being blanked out due to shock wave as wing went transonic.

If that was the true cause and the pilot could not achieve nose up trim another way, there would be a large potential for continuation in the 'nose down tuck' - which could easily lead to structural failure - in any airplane - at those kinds of speeds. 

That would not be a condemnation of the 262 structural integrity as all WWII types were at the edge (or beyond) structurally at .85 M, as they sure as hell weren't designed for 'negative G' at those aerodynamic load conditions.


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## Waynos (Oct 13, 2008)

quote ; " Waynos,

Let's get something clear here,"

Thats a rather arrogant turn of phrase, if I may say so soren. I don't appreciate being talked down to, thank you.

Especially as you backed it up with nothing more than a statement that contradicts what I have read in more than one source. Who am I to believe, and why?

For example, the exact quote from 'Spitfire' by Glancey on page 160 is;

"Tests demonstrated that the 262 would fly out of control at a speed in excess of mach 0.86 and that its airframe was in danger of breaking up at a marginally higher speed, the Spitfire had bettered this in 1943". 

Regarding the mach 0.94 dive I mentioned earlier I have also found this quote, from the same book, page 115, attributed to Jeff Quill when talking of the event;

"That any operational aircraft off the production line, cannon sprouting from its wings and warts and all could readily be controlled at this speed when jets such as the Meteor, Vampire, P-80 etc cannot is certainly extraordinary"


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## kool kitty89 (Oct 13, 2008)

The comment about the Spitfire being "readialy controlled at this speed" doesn't make sense.

If the spitfire genuinely could dive to such speeds, it they would be terminal dives, not controlled ones. (as would the .89 Mach dive) It would be well above critical mach and the elevator would be ineffective. (rudder and ailerons may still be functional) 

Now, the Spitfire may have gotten luck, and was inherantly stable above critical Mach, but that's a different issue. Also, to avoid structural damage to the airframe at such speeds, buffeting must have been relatively minimal, or the speeds were only maintained for very short periods of time. (the vibrations and flexing from buffeting can cause damage independantly of -G or stress directly related to the high speed flow)


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## Soren (Oct 13, 2008)

I aint talking down to you Waynos, I'm just telling you that the tests didn't conclude anything about the Me-262's airframe not being able to take the stresses of a Mach 1 dive. And the airframe could take it as established in studies done in 1999. The problem was the pitching down above 0.86 Mach, something which could only be corrected by use of horizontal stabilizer trim, which I have heard the British weren't aware of, I think Hohun knows about this.

There are no miracles in physics mate, all things in aero can be measured, just like your sig lets us know.


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## Soren (Oct 13, 2008)

kool kitty89 said:


> The comment about the Spitfire being "readialy controlled at this speed" doesn't make sense.
> 
> If the spitfire genuinely could dive to such speeds, it they would be terminal dives, not controlled ones. (as would the .89 Mach dive) It would be well above critical mach and the elevator would be ineffective. (rudder and ailerons may still be functional)
> 
> Now, the Spitfire may have gotten luck, and was inherantly stable above critical Mach, but that's a different issue. Also, to avoid structural damage to the airframe at such speeds, buffeting must have been relatively minimal, or the speeds were only maintained for very short periods of time. (the vibrations and flexing from buffeting can cause damage independantly of -G or stress directly related to the high speed flow)



Agreed. 

It is a case a false speed readings that's all, a known issue at very high subsonic speeds. The Spitfire couldn't go that fast without falling apart.


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## drgondog (Oct 14, 2008)

Soren said:


> I aint talking down to you Waynos, I'm just telling you that the tests didn't conclude anything about the Me-262's airframe not being able to take the stresses of a Mach 1 dive. And the airframe could take it as established in studies done in 1999. The problem was the pitching down above 0.86 Mach, something which could only be corrected by use of horizontal stabilizer trim, which I have heard the British weren't aware of, I think Hohun knows about this.
> 
> There are no miracles in physics mate, all things in aero can be measured, just like your sig lets us know.



*If true regarding the slab elevator being blanked out in turbulent flow, how did elevator trim work to solve the problem. If there is no laminar flow over the elevator, there is nothing for the trim tab to work on.*

If the issue was not turbulent flow but compressibility initiation over the elevator, the movable and boosted 262 elevator would have worked fine.

If it was the shock wave moving the Cp aft to ~ 50% Chord over the wing, causing a pitch down moment but elevator still in flow (i.e not blanked) then the elevator would still work and no trim required.

Which case for the 262?


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## Waynos (Oct 14, 2008)

I can well believe that the speed reading was not entirely accurate but there is little doubt that at least m0.9 was reached and no doubt at all that it was the fastest diving aircraft of the 2nd world war (er, except the V-2 I suppose). This much was proven with real aircraft on actual flight tests. 

If mathematical theory 'proved' the idea that the 262 could withstand mach 1 in 1999, why did Willy Messerschmitt support the RAE findings? wouldn't he have published the opposite view, at some point if not immediately? but he never did and even the intended 'high speed' HG.III model was not tested beyond mach 0.86 in any wind tunnel.


The controllability aspect is a good one however, I suppose that the fact the Spitfire recovered and landed with no damage is evidence of controllability, perhaps?

In a further quote on the subject, and going back to the wings being thinner than the accepted norm the aerodynamiscist Sir Morien Morgan who specialised in the transonic region during the 1950's wrote with hindsight;

"Considering that he could have had little knowledge of Mach effects, Mitchells decision to use such a thin wing was not only bold, it was inspired. We know know it was a close run thing. Had he made it just a little thinner the wing would have been too weak and aileron reversal would have been encounterd lower down the speed scale and if that had happened the Spitfire would have been just one more aircraft that didn't quite make the grade"

Again, this points to a wing that was not just thin, but unusually so.


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## Soren (Oct 14, 2008)

drgondog said:


> *If true regarding the slab elevator being blanked out in turbulent flow, how did elevator trim work to solve the problem. If there is no laminar flow over the elevator, there is nothing for the trim tab to work on.*
> 
> If the issue was not turbulent flow but compressibility initiation over the elevator, the movable and boosted 262 elevator would have worked fine.
> 
> ...



Bill,

You're missing the fact that the entire horizontal stabilizer was movable on the Me-262 and was used for trim.


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## Soren (Oct 14, 2008)

Waynos said:


> I can well believe that the speed reading was not entirely accurate but there is little doubt that at least m0.9 was reached and no doubt at all that it was the fastest diving aircraft of the 2nd world war (er, except the V-2 I suppose). This much was proven with real aircraft on actual flight tests.



Well I disagree. Also the a/c which did reach Mach .9 doesn't seem like it didn't take any damage, it looked rather terrible afterwards IMO, and thats when it probably didn't even reach Mach .9.



> If mathematical theory 'proved' the idea that the 262 could withstand mach 1 in 1999, why did Willy Messerschmitt support the RAE findings? wouldn't he have published the opposite view, at some point if not immediately? but he never did and even the intended 'high speed' HG.III model was not tested beyond mach 0.86 in any wind tunnel


.

Willy wasn't the man behind the Me-262 Waynos, Dr. Waldemar Voigt designed the a/c and had his own team leading the research surrounding it. 

Furthermore no WW2 a/c designer knew all there was to know about the transonic region much less the supersonic one, so how do you expect them to correctly answer a question regarding it ?


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## Waynos (Oct 14, 2008)

But he didn't say 'I don't know'. He agreed with the RAE. And he DID design a supersonic jet that flew in the HA 300 so he would have been qualified to contradict his earlier position by the mid 1960's at the very latest. But, as far as I know at least, he didn't, for whatever reason.

Speaking purely subjectively I think the p1101 could have gone supersonic in a dive relatively safely but I am happy to accept the RAE/Messerschmitt view that the 262 could not.

Yes, Martindales Spit did take a lot of damage, due to the catastrophic failure of the reduction gear, but it does not follow that this failure would automatically occur in every engine when diving at this speed (even if it is quite likely to happen), so the fact that the 81 Sqn aircraft did not suffer this failure cannot be taken as proof that it was travelling more slowly, a sample of only 2 cannot be indicative.

The IAS of Martindales dive was 0.92, this was subsequently revised downwards to 0.89 and is considered the accurate speed.


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## drgondog (Oct 14, 2008)

Soren said:


> Bill,
> 
> You're missing the fact that the entire horizontal stabilizer was movable on the Me-262 and was used for trim.



I didn't miss the point - I said slab elevator. And then I asked you how 'trim' would solve the problem if the entire elevator was immersed in turbulent flow.


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## Graeme (Oct 14, 2008)

Waynos said:


> Jeff Quill



Hi Wayne.

Quill wrote an extensive article for AI (September '76) on the 40th anniversary of the Spitfire and he discussed the high speed dive tests, as you described. I've tossed in a 'graph' for good measure...


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## ponsford (Oct 14, 2008)

If those dive tests were done in 1942 then I presume the Mustang was either Mk I or II? I wonder if the P-51 B would have done any better considering the redesigned radiator inlet. I've no issue with the Spitfire hitting Mach 0.89. There's this:


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## Juha (Oct 14, 2008)

Hello Ponsford
you beat me by 20 minutes, I just dug out my copy of that report from the hard drive of my second pc (ret.). But the main thing is that the report is posted here.
The key word is TYPICAL, it wasn't just one odd dive but series of dives flown by the pilots of High Speed Flight Section, one of which was certain Lt Cdr Eric Brown.

Juha

Addition, Ponsford, P-51B might well have done better, if not for other reason at least it could have climbed higher, Allison Mustang dives were started at 28000ft because of its ceiling limitations.


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## Waynos (Oct 14, 2008)

As I was hurling quotes in earlier I'd also like to add this one, not really relevant to this argument, but it stood out for me as I was doing some further research into the Spitfires creation. Its from RJ Mitchell and it dates from 1934 during detail design;

"I don't give a toss whether the wings are elliptical or not, as long as they cover the guns!"

This retort was hurled at Beverley Shenstone, late of Heinkel, who first put forward the idea of the elliptical profile. Interesting or what?


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## Soren (Oct 14, 2008)

drgondog said:


> I didn't miss the point - I said slab elevator. And then I asked you how 'trim' would solve the problem if the entire elevator was immersed in turbulent flow.



I don't believe the entire 'horizontal stabilizer' was immersed in turbulent flow Bill, the elevators might have been because of the shockwave produced at the LE of the stabilizer, but not the entire stabilizer. So like Muthke one could trim the a/c out of the dive by utilizing the fully movable horizontal stabilizer, which is what he did.

The British however don't seem to have known about the full use of the fully movable horizontal stabilizer trim and used only the trim tabs, which explains their findings.


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## Soren (Oct 14, 2008)

Waynos said:


> But he didn't say 'I don't know'. He agreed with the RAE. And he DID design a supersonic jet that flew in the HA 300 so he would have been qualified to contradict his earlier position by the mid 1960's at the very latest. But, as far as I know at least, he didn't, for whatever reason.
> 
> Speaking purely subjectively I think the p1101 could have gone supersonic in a dive relatively safely but I am happy to accept the RAE/Messerschmitt view that the 262 could not.



But how does that verify one comment of his on the Me-262 ? Like I said he didn't design the a/c and he wasn't part of the research team, so his total technical knowledge on the Me-262 would've been limited as he didn't work with the a/c every day.


Anyway I don't think we're going to agree on this so lets just agree to disagree.



> The IAS of Martindales dive was 0.92, this was subsequently revised downwards to 0.89 and is considered the accurate speed.



Now guess what the IAS of Muthke's dive was, and then note that the Me-262's speedometer was the most accurate around with built in compressibility correction.


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## Juha (Oct 14, 2008)

Soren
Quote:"The British however don't seem to have known about the full use of the fully movable horizontal stabilizer trim and used only the trim tabs, which explains their findings."

have you source for that? RAF had a/c in service with movable horizontal stabilizer at that time.

"Now guess what the IAS of Muthke's dive was, and then note that the Me-262's speedometer was the most accurate around with built in compressibility correction."

Now those Spitfires were fully instrumented for those high speed dives, so we know what their instrument readings were, how about Muthke's 262?


Juha


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## Soren (Oct 14, 2008)

Juha said:


> have you source for that? RAF had a/c in service with movable horizontal stabilizer at that time.



So ? 



> Now those Spitfires were fully instrumented for those high speed dives, so we know what their instrument readings were, how about Muthke's 262?



His speedometer hit its max = 1,100 km/h Juha.


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## Waynos (Oct 14, 2008)

Don't forget also the Miles 'Gillette Falcon', the first aircraft in the world to use an all-flying tail specifically intended for control at high speeds. It flew in 1944 and was built specifically in response to the need to be able to control the Miles M.52 at supersonic speeds. It is recognised that without this device Yaegers attack on the sound barrier in the X-1 could not have been successful so yes, the British were quite well up on this asp0ect of controllability at the time.


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## kool kitty89 (Oct 14, 2008)

His air speed indicator was maxed out. (at 1,100 km/h)


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## kool kitty89 (Oct 14, 2008)

Also in Graeme's pose, you'll clearly note the 13% thickness note in the article for the Spitfire's wing.


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## Juha (Oct 14, 2008)

Soren
I asked independent proof, like flight test recorder. Not what someone claimed 20 years after the test.

Juha


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## Waynos (Oct 14, 2008)

Yes, it was 13% at the root tapering to only 9% further out. I think this is what made the difference, from what I have read other fighters wings did not do this, though I stand to be corrected if this is not the case.

As I mentioned earlier, during the 1946 tests Supermarine were quite perturbed to learn that their brand new, laminar flow winged, Spiteful was actually slower in the dive than the Spitfire was, especially as this same wing was being grafted onto their new jet fighter, the type 392, which had started its development as a jet-Spitfire! The production Attacker emerged with a max level speed of 590 mph in 1947, about 50 more than the 262, but it still could not outdive the Spitfire.


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## kool kitty89 (Oct 14, 2008)

Tapering the wing thickness/chord was a rather common feature, the P-36/P40, for example, had a root section of NACA 2215 (15%) and 2209 (9%) at the tip. It seems tohave been rather uncommon for a wing to feature constant thickness. (though iirc the Whirlwind featured a constant NACA 23015 from root to tip, and the P-63 featured a constant 16% laminar flow airfoil)

The Me 262's airfoil was 11% at the root and 9% at the tip. (~8.6% taking sweep into acount)

However it would be the root (as it's the tickest) that would reach critical Mach first. 
If the Spitfire's tailplane was thin enough and the tail didn't become immersed in turbulent flow from the wing above critical Mach, the elevator would still function up to until the tailplane its self reached critical mach.


As to the a/c being able to recover from a terminal dive, as can be seen in Ponsford's chart, the spitfire was only above ~.82 Mach from ~33,000 ft to ~22,000 ft. (for a total of ~22 seconds, and above .84 Mach for ~18 seconds) And the recovery was made well below these altitudes.


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## kool kitty89 (Oct 14, 2008)

Soren said:


> The British however don't seem to have known about the full use of the fully movable horizontal stabilizer trim and used only the trim tabs, which explains their findings.



Soren did the Me 262 feature functioning elevator trim tabs? 

According to US reports, the a/c tested a Wright field apeared to be intended to used adjustable trim tabs for both the elevator and ailerons, but the ailerons were only fitted with ground-adjustable tabs, and the elevator tabs had been riveted in place. (trim being effected by the adjustable tailplane) The rudder being the only surface fitted with an in-flight adustable trim tab. 

The US manual on the Me 262 also warned against using stabilizer trim changes when entering or recovering from dives as it could lead to overcontrol and possible overstressing of the airframe. (the manual did make many refrences to the stabilizer trim, so, at least for tests at Wright field, they were well aware of its use)


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## ponsford (Oct 15, 2008)

Juha said:


> Hello Ponsford
> you beat me by 20 minutes, I just dug out my copy of that report from the hard drive of my second pc (ret.). But the main thing is that the report is posted here.
> The key word is TYPICAL, it wasn't just one odd dive but series of dives flown by the pilots of High Speed Flight Section, one of which was certain Lt Cdr Eric Brown.
> 
> ...



Sorry about that Juha. It wasn’t intentional, honest  Good point about the altitude of the Mustang. That hadn’t occurred to me. I just remembered this report on the P-51 D dive: 

Compressibility Dive Tests Part I on North American P-51D Airplane (Mustang IV), AAF No. 44-14134

“The airplane was flown to a maximum true Mach Number of 0.85 during the twenty-sixth dive on 9 September 1944 and to a maximum calibrated airspeed of 486 MPH during the twenty-eighth dive on 9 September 1944.”

“In extreme war emergency the airplane can be dived to a Mach Number of 0.83 (400 MPH Indicated Airspeed at 25,000 feet) if a very gradual pull-out is made.”


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## drgondog (Oct 15, 2008)

I have seen several references from NAA, USAAF and RAF that detailed terminal dives - all peaking at .85, and very descriptive of the 51D/Mustang IV at 'the edge' - particularly the strengthened ammo cover door bulge..and severe buffeting

It is also clear that the Spitfire dive tests under similar test conditions and calibrations achieved a higher Mach than the 51. 

Instrumentation being what is was in 1944-1946 leads one to obtain a full report to determine the methods of calculation - most of which were instrumentation corrections using analytical methods for compressibility.

I have yet to find a definitive dive report on the 262 (i.e. not anecdotal) which describes the dive, the tuck and the methods used to a.) warn of the phoenomena and b.) the approved Me method of recovery. Perhaps Soren has one.


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## Soren (Oct 15, 2008)

kool kitty89 said:


> Soren did the Me 262 feature functioning elevator trim tabs?



Yes ofcourse, I have no idea why the one at Wright field didn't.


For reports on the Me-262 read here:
Flying the Messerschmitt Me-262


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## drgondog (Oct 15, 2008)

Soren said:


> Yes ofcourse, I have no idea why the one at Wright field didn't.
> 
> 
> For reports on the Me-262 read here:
> Flying the Messerschmitt Me-262



So, now that you acknowledge that a trim tab existed on the 262 slab tail - what is the answer to the high mach tuck issue? and why the trim tabs weren't the solution?


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## Soren (Oct 15, 2008)

Acknowledge ? Bill I've never claimed there weren't any, I just pointed out that the entire horizontal stabilizer was used for trim, esp. in cases where the trim tabs weren't enough. (The Bf-109 had the same feature, which is what allowed it to recover from high speed dives quicker than other fighters)

The only way to get out of the negative G dive the Me-262 would start after 1,100 km/h was to utilize the movable horizontal stabilizer, the elevators and therefore also trim tabs being rendered useless because of turbulent flow.


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## kool kitty89 (Oct 15, 2008)

http://www.zenoswarbirdvideos.com/Images/Me262/262PilotHandbook.pdf

Soren, that site had the very manual I was referring to. (with the comment of no functioning trim tabs) Accordingly, all trim changes for pitch are made by adjusting the horizontal stabilizer. 

Elevator trim tabs would seem redundant given the stabilizer trim, did the Bf 109 feature elevator tabs as well?

I didn't see any mention of elevator tab controls in the cocpit instument pannel diagrams, but I haven't read the other articles there yet.


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## Soren (Oct 15, 2008)

> Soren, that site had the very manual I was referring to. (with the comment of no functioning trim tabs) Accordingly, all trim changes for pitch are made by adjusting the horizontal stabilizer.



But that is the Me-262 at Wright field, not the one in Britain. That the Me-262 at wright field featured rivetted trim tabs is very unusual. 

As for the 109, it has elevator tabs as-well yes.


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## kool kitty89 (Oct 15, 2008)

http://www.zenoswarbirdvideos.com/Images/Me262/ME262WendeL.pdf

I finished reading through the British article and found no menthin to elevator trim tabs, the rudder tab was mentioned several thimes though. Also, the tailplane trim was mentioned in this article as well.


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## Soren (Oct 15, 2008)

Here's a picture of the RAE Me-262, you can slearly see the tabs:


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## kool kitty89 (Oct 16, 2008)

Soren, I know the tabs exist, but that doesn't mean they were used.
Accoring to this extensive article on the Me 262's construction: http://www.enginehistory.org/German/Me-262/Me262_Airframe_2.pdf

It mentions that:


> As is the case with several other German planes, the 262's all metal stabilizer is adjustable, the incidence being changed by a small electric motor operating a screw jack mounted inside the fin fairing on the front face of the frame to which the vertical fin is bolted. This unit is
> 
> --------------------------------------------------------------------------------
> Page 15
> mass-balanced trim tabs set near the inboard end. These tabs were apparently designed as interchangeable servo units, for a small arm at the outboard end extends up from the right one and down from the left, and captured enemy documents show an anchoring arm designed into the stabilizer trailing edge. _However,the operational experience or Allied bombing made completion of this plan impossible, for the tab arms were not connected to the stabilizer and, in fact, *the tabs had been riveted into immobility* by small gusset plates at each end._ Nevertheless, each tab had four hinges, with ball bearing units at each end and pins through yokes forthe two in the middle. As is the case with the rudder trim tab, the trailing edges of the tabs are nicely flush riveted..


 (the article also mentions the aileron tabs being intended to be of the in flight adjustable servo type, but were simple ground adjusted tabs in practice)


In any case, that British pilot's notes on the 1945 tests makes it clear that they were at least aware of the use of the tailplane trim. Indeed, there is no other mention to pitch trim than that pertaining to the variable incedence tailplane. (wether that trim function was used in dives is another issue)


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## kool kitty89 (Oct 16, 2008)

I believe one of the riveted gusset plates is visible in this immage:






Look closely at the inboard trailing edge of the tab on the right.



And on a somewhat different note: 


Waynos said:


> Don't forget also the Miles 'Gillette Falcon', the first aircraft in the world to use an all-flying tail specifically intended for control at high speeds. It flew in 1944 and was built specifically in response to the need to be able to control the Miles M.52 at supersonic speeds. It is recognised that without this device Yaegers attack on the sound barrier in the X-1 could not have been successful so yes, the British were quite well up on this asp0ect of controllability at the time.



It should also be noted that, whaile not developed for high Mach number control, both the Bf 109 and Fw 190 featured variable incidence tailplanes. (for trim purposes; I believe the 109's mechanism was very similar to that of the Me 262)


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## drgondog (Oct 16, 2008)

Soren said:


> Acknowledge ? Bill I've never claimed there weren't any, I just pointed out that the entire horizontal stabilizer was used for trim, esp. in cases where the trim tabs weren't enough. (The Bf-109 had the same feature, which is what allowed it to recover from high speed dives quicker than other fighters)
> 
> *And I pointed out the two possible conditions which would cause a nose down tuck - both involving some degree of issue with the elevator at compressibility range - and you have not pontificated on the 'final word' on that question..*
> 
> The only way to get out of the negative G dive the Me-262 would start after 1,100 km/h was to utilize the movable horizontal stabilizer, the elevators and therefore also trim tabs being rendered useless because of turbulent flow.



Lol - you wish to claim that the 262 reached 1100KM/hr BEFORE compressibility started? You know that is about 593 kts and at SL = .89 Mach and 593 kts~ 95. Mach at 15000 feet, and .98M at 25000ft - at STP?

At what altitude do you propose the 262 ever came close to 1100km/hour? and that Mach number would Be?


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## Soren (Oct 16, 2008)

drgondog said:


> Lol - you wish to claim that the 262 reached 1100KM/hr BEFORE compressibility started? You know that is about 593 kts and at SL = .89 Mach and 593 kts~ 95. Mach at 15000 feet, and .98M at 25000ft - at STP?
> 
> At what altitude do you propose the 262 ever came close to 1100km/hour? and that Mach number would Be?



Bill the airspeed indicator went off the scale at 1,100 km/h at 36,000 ft, at which altitude the speed of sound is 1,062 km/h. Mutke notes that heavy vibrations started around that time and the a/c started to nose down uncontrollably, until suddenly the vibrations stopped. Mutke then started to recover the dive by shutting the engines and trimming the movable horizontal tail plane, and while pulling up the vibrations suddenly started again, but he managed to pull out and reduce the speed to 500 km/h.


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## Soren (Oct 16, 2008)

kool kitty89 said:


> I believe one of the riveted gusset plates is visible in this immage:
> 
> Look closely at the inboard trailing edge of the tab on the right.










Yep I see it KK, small rectangular plate at the far left trailing edge of the tab(red circle above), they were clearly rivetted in place on that a/c, I agree with that. 

But note the servo arms have been removed, unlike on the RAE specimen where they are clearly visible.


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## drgondog (Oct 16, 2008)

Soren said:


> Bill the airspeed indicator went off the scale at 1,100 km/h at 36,000 ft, at which altitude the speed of sound is 1,062 km/h. Mutke notes that heavy vibrations started around that time and the a/c started to nose down uncontrollably, until suddenly the vibrations stopped. Mutke then started to recover the dive by shutting the engines and trimming the movable horizontal tail plane, and while pulling up the vibrations suddenly started again, but he managed to pull out and reduce the speed to 500 km/h.



Soren - in all seriousness no one relies on airspeed indicators for accuracy above .6-.65 M. P-51's were 'recorded' (airspeed indicator) as having reached 660mph in a dive - which is absurd. The highest terminal dive speed for a 51 was in the 505-510mph range at 20,000 feet.

What other reference would support more than say 1000km/hr TAS? That would be ~ . 86 at 15000 and .89 at 25,000 - which looks to be a real problem for that wing/nacelle combo in transonic regime.


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## Soren (Oct 16, 2008)

I'm not saying the speed readings were accurate Bill, they were obviously too high when the vibrations started cause as noted the speed of sound is below 1,100 km/h at 36,000 ft. However all the characteristics he notes pretty much concludes he went supersonic, and like modern aerodynamical studies have shown it indeed is possible. So I have absolutely no reason not to believe he went supersonic, other than your unsupported claim that he didn't based on a simple hunch.


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## drgondog (Oct 16, 2008)

Soren said:


> I'm not saying the speed readings were accurate Bill, they were obviously too high when the vibrations started cause as noted the speed of sound is below 1,100 km/h at 36,000 ft. However all the characteristics he notes pretty much concludes he went supersonic, and like modern aerodynamical studies have shown it indeed is possible. So I have absolutely no reason not to believe he went supersonic, other than your unsupported claim that he didn't based on a simple hunch.



Soren - Then of course you believe Tommy Hayes when he reported that he was doing 660 mph chasing a 109 in a dive because the instruments showed he was close and the Mustang exhibted 'charcteristics' of supersonic transition??

I would not characterize my skepticism on a simple hunch, nor should you exhibit belief based on Mutke's beliefs any more than Hayes.

What is the Cd0 of the 262 versus the F-86? If you say 'studies show' then surely you can dig up the 'studies' that show that the 262 is capable of supersonic speed in a dive.


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## Graeme (Oct 16, 2008)

What's the postwar Czech experience with the "Me-262"? (S-92/CS-92) Do they have any 'supersonic' anecdotes?


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## drgondog (Oct 16, 2008)

From Wikipedia with following references cited.


"Messerschmitt also conducted a series of flight tests with the series production Me 262. In dive tests, it was determined that the Me 262 went out of control in a dive at Mach 0.86, and that higher Mach numbers would lead to a nose-down trim that could not be countered by the pilot. The resulting steepening of the dive would lead to even higher speeds and disintegration of the airframe due to excessive negative g loads.

Despite the necessity to gain experience in high-speed flight for the HG II and III designs, Messerschmitt undertook no attempts to exceed the Mach 0.86 limit for the Me 262.

After the war, the Royal Aircraft Establishment, at that time one of the leading institutions in high-speed research, re-tested the Me 262 to help with British attempts at exceeding Mach 1. The RAE achieved speeds of up to Mach 0.84 and confirmed the results from the Messerschmitt dive tests. Similar tests were run by the Soviets. No attempts were made to exceed the Mach limit established by Messerschmitt.

"After Willy Messerschmitt's death, the former Me 262 pilot Hans Guido Mutke claimed to be the first person to exceed Mach 1, on 9 April 1945 in a Me 262 in a "straight-down" 90° dive. This claim is disputed because it is only based on Mutke's memory of the incident, which recalls effects other Me 262 pilots observed below the speed of sound at high indicated airspeed, but with no altitude reading required to determine the actual speed. Furthermore, the pitot tube used to measure airspeed in aircraft can give falsely elevated readings as the pressure builds up inside the tube at high speeds. Finally, the Me 262 wing had only a slight sweep incorporated for trim (center of gravity) reasons and likely would have suffered structural failure due to divergence at high transonic speeds. One airframe (Me 262 HG1 V9 WNr130 004 VI+AD [22]) was prepared with the low-profile Rennkabine racing canopy and may have achieved an unofficial record speed of 606 mph, altitude unspecified.[23]"

22 Radinger and Schick 1996, p. 75. 
^ Radinger and Schick 1996, pp. 75, 79. Note: Willy Messerschmitt July 1943. 
^ Radinger and Schick 1996, p. 79. 
^ Radinger and Schick 1996 
23^ Flying Review, 1960s, date unkown 




What are your sources Soren?


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## Vincenzo (Oct 16, 2008)

the problem with wikipedia that all can write and can write that some it's take from a source


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## drgondog (Oct 16, 2008)

Vincenzo said:


> the problem with wikipedia that all can write and can write that some it's take from a source



I understand Vicenzo - I have written sections of it myself. The only point I would make is that the references cited are valid. 

The 262 was slightly cleaner than a P-80 which was much draggier than an F-86. The F-86 was able to get through the transonic and into supersonic in a dive with no severe stability issues.

Soren would have you believe a 262 could go somewhere between ".89 and .96 Mach" when nothing other than Mutke's 'say so' based on his airspeed indicator with no substantiation other than his post flight claim.

Soren says the 262 can exceed the speed of sound today. Here is the website of Stormbirds - the guys building the 262 around the GE J85 engine
Me 262 PROJECT TECHNICAL DATA

They are REAL clear about Do Not Stress the airplane to 600mph and have it placard at 540mph - that is right in the strikezone for what they describe as the Technical data from Messerschmidt. So guys that are building them and flying them have no preconceived notions that the 262 is more than a .86M aircraft MAXIMUM.

If he wants folks to believe the 262 is 'capable of supersonic' he needs references from engineers and data to back his claim.


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## kool kitty89 (Oct 16, 2008)

The comment on wing sweep on the wikipedia quote really has nothing to do with it. The advantage of sweep in the transsonic region being that the chord of the wing is phisically increased by sweeping the wing back (or foreward) to the extent that the COS of the sweep angle muliplied by the original thickness/chord will give the "real" thickness/chord. However, a thin, straight wing will work just as well for this purpose. (hence the Bell X-1, Douglass Skystreak, F-94C, CF-100, etc)


Now at supersonic speeds, swept back wings (or a Delta planform) have other advantages, but that's a different issue.

Additionally, the portion of the Me 262's wing that was swept back (for trim purposes) was only that outboard of the engines, the inboard portion being unswept (although the LE of the inboard section was extended to match the sweep angle of the LE of the rest of the wing). So, while the 18.5° wing sweep of the outer wing would result in the airfoil thicness being resuced to ~94.8% of the original thickness, the inboard section will be unaffected. (additionally the root had max thickness at 35% chord while this increased to 40% for the entire outboard section)


Given that the Skystreak, F-94C, and CF-100 all had wings of 10% thickness (the former two being laminar flow types, and the latter being a simple, unmodified NACA 0010) it would seem that the Me 262's wing was fairly close to being satisfactory in transsonic flight. (being 10% thicker at the root)



*Bill*, I agree that the control problems on the Me 262 should start to manifest at a TAS of ~914 km/h (568 mph/494 kt) at ~36,000 ft. I'm not entirely sure Soren was implying that the airspeed indicated on the Me 262 was close to the TAS, I think it may be another case of misenterpretation.

*Soren*, could you clarify what you meant by the 1,100 km/h figure? (did you simply mean that this was the indicated speed when the control problems occured?)


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## kool kitty89 (Oct 16, 2008)

Also, the study Soren is referring to, I believe is the same one Delcyros introduced on the first page of this thread. 

also, Hans Guido Mutke - Wikipedia, the free encyclopedia


> A computer based performance analysis of the Me 262, carried out in 1999 at the Munich Technical University, has shown that the Me 262 could exceed Mach 1.





And, I'm not entirely sure of the accuracy of everything on the Me 262 reproduction website. While I too noticed that rather stark announcement that the 540 mph speed would not be exceeded, even thought the Me 262 should be well capable of 620+ mph below 10,000 ft given its Mach limit, and that the official "never excced speed" was also well above this figure.

It should be noted that in one of their featured videos that it is stated that "its top speed is *560 knots*, just like the originals." 


Also they claim that


> *The few originals (less than 10 worldwide) that still exist are now cloistered in museums, never to fly again. * They are so rare and so valuable that to risk them in their natural element is considered by many to be nothing short of foolhardy. None are even close to being in airworthy condition. To see an Me 262 streaking through the sky again would seem to be a daydream ... until now!



Firstly, there are at least 11 surviving Me 262's (including 2 Czech S.92's) and Me 262 A-1a/U3 W.Nr.500453 (fromerly owned by Planes of Fame, and the same ship Howard Hughes tried to use for racing) is now part of Paul Allen's "Flying Heretage Collection" and is currently being restored to flying condition. (which, incedentally, is also located in Washinton, in Arlington, pretty close to Everett -both being in west Sonhomish county-)


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## kool kitty89 (Oct 16, 2008)

drgondog said:


> *
> If the issue was not turbulent flow but compressibility initiation over the elevator, the movable and boosted 262 elevator would have worked fine.
> *


*

I caught this a while back, but forgot to ask. What do you mean by "boosted 262 elevator." Did it feature boosted controls?*


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## drgondog (Oct 16, 2008)

kool kitty89 said:


> The comment on wing sweep on the wikipedia quote really has nothing to do with it. The advantage of sweep in the transsonic region being that the chord of the wing is phisically increased by sweeping the wing back (or foreward) to the extent that the COS of the sweep angle muliplied by the original thickness/chord will give the "real" thickness/chord. However, a thin, straight wing will work just as well for this purpose. (hence the Bell X-1, Douglass Skystreak, F-94C, CF-100, etc)
> 
> 
> *KK- the purpose of the sweep is to reduce the freestream airflow to a normal (chord wise) and transverse (spanwise) flow. By virtue of the sweep, the chordwise flow vector is reduced to the Cos of the sweep angle At The 1/4 Chord - not the leading edge. You can see that the effect is to significantly delay the transonic occurance over the wing..*
> ...



494kts at STP at 35000 is ~ .86M which is the alleged 'start of disintegration' for a 262 - every reference I have seen for Messerschmidt is Do not Eceed .84 Mach.

FYI for Kts the Speed of sound is 29.04*sqrt(T) where T = Temp in Rankin

At 36K, T=390.5
At 25K =429.6
At 15K =465.2
At SL = 518.7 for Standard Temp and Pressure (59 Degree F, 2116 lb/ft^^2 at SL)


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## Soren (Oct 17, 2008)

Bill,

The reason the reproduction Me-262's aren't pushed past 500 mph should be quite clear to you. It isn't because of doubts regarding wether the a/c will disintigrate or not, it is for other obvious safety reasons only. They don't push Mustangs to 430 mph today either, or F-86's to 600 mph, again for safety reasons.

From the site:

_The fact remains that the airframe was never designed to handle the stress loads encountered at speeds in the 600 mile per hour range. To push the aircraft into this environment simply because additional power "happens to be available" is a highly dangerous and ill-advised move.

In the interest of safety, the Me 262 Project will be placing a placarded airspeed limitation upon the jets in the vicinity of 500 MPH. The official position of the project *is that there is simply no need -- or benefit -- in flying these aircraft any faster*. _

Or would you advice them to put millions of dollars on stake just to try and break the sound barrier ? 

Anyway I believe modern research done by professional aerodynamicists more than any hunch someone might have.


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## kool kitty89 (Oct 17, 2008)

Ok Bill, I was using .86 Mach. (I'd though the .84 was from the British test only)

Going back to the 560 kt comment on the Me 262 Project video, that value would fit very well with .84 Mach at seal level. (almost exactly for 20*C, 527.7 Rankine)


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## drgondog (Oct 17, 2008)

kool kitty89 said:


> Ok Bill, I was using .86 Mach. (I'd though the .84 was from the British test only)
> 
> *Yes and yes from the reports I have read. Msmt test pilot Lindner recount*
> 
> Going back to the 560 kt comment on the Me 262 Project video, that value would fit very well with .84 Mach at seal level. (almost exactly for 20*C, 527.7 Rankine)



Yes it would, but to get to that speed I believe he would be in a shallow dive? The guys on the Stormbird Project are very serious about a max 540mph on the deck placard according to the website

I just finished reading the Lindner debriefing report detailing the handling characteristics of the dive issues starting at .83 and increasing up to .86 at around 6,000 meters. The issue was a.) severe onset buffeting in the nose tuck and b.) major increase in stick forces from 15g to 50kg in that Mach range. The issue in getting out of this situation was on one arm a "110 pound curl to move the stick slightly aft" while freeing up the other hand for the trim wheel.

This suggests to me that the experience was the rearward movement of the aircraft wing center of pressure as the ship experienced Mcrit and the shock was was moving to the 50% chord region. It sounded like the slab tail was still 'effective' in the sense that it wasn't totally immersed in the turbulent flow.

Correspondingly the major stick forces in the cockpit suggest huge bending loads in the aft section at the vertical stabilizer/tail section attach points to 
the fuselage... that should be the area of major potential failure 

BTW - .86Mach at 6,000 meters is ~ 1001km/hr for STP as you probably know. About 529kts and 609mph.

I'm still digging to try to find any example of a complete push over to anything remotely looking like a vertical dive. By all accounts so far the factory Do Not Exceed was 950 with recommendations for nose up trim.

The Stormmbird Rising book by Morgan seems pretty comprehensive


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## delcyros (Oct 17, 2008)

From what I have read, Messerschm. werkspilots carried out several test programs to establish high speed trials with the Me-262. The procedure was a gradual increase in dive angle which lead to a number of fatal accidents and was concluded with the established Mach numbers reported not to exceed.
This procedure was very dangerous for the airframes due to stress loads and no vertical dives were attempted.


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## Soren (Oct 17, 2008)

According to the POH the dive speed limit is 1,050 km/h.


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## pbfoot (Oct 17, 2008)

Soren said:


> According to the POH the dive speed limit is 1,050 km/h.


Whats a POH , Pilots operating handbook?


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## Soren (Oct 17, 2008)

Roger that Pbfoot.


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## Soren (Oct 17, 2008)

Correction, the dive speed limit listed in the POH was 1,000 km/h.


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## kool kitty89 (Oct 17, 2008)

That would be the indicated speed, correct?


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## Soren (Oct 17, 2008)

Doesn't say, but the Me-262 had two air speed indicator needles, one listing IAS the other TAS so I suppose it is TAS.


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## kool kitty89 (Oct 18, 2008)

It wouldn't really give TAS though, it would be an altitude corrected value, but still with some limitations. (was temperature taken into account?) You mentioned earlier that the Me 262's airspeed indicator featured compressibility correction as well, correct?


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## Soren (Oct 18, 2008)

I agree it wouldn't be the true TAS but rather an approximation of it. And yes AFAIK compressibility effects were taken into account as-well.

As for temperature, no idea mate, if so I would assume it needed to be punched in manually via observation.


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## drgondog (Oct 18, 2008)

Soren said:


> Bill,
> 
> The reason the reproduction Me-262's aren't pushed past 500 mph should be quite clear to you. It isn't because of doubts regarding wether the a/c will disintigrate or not, it is for other obvious safety reasons only. They don't push Mustangs to 430 mph today either, or F-86's to 600 mph, again for safety reasons.
> 
> ...



And the 'aerodynamic report has a Structural analysis and Stability and Control analysis section? I know I would go immediately to look for three sections. 1.) drag rise profile and engine inlet characteristics in the Transition Mach range, 2.) the control forces required to maintain pitch controls, 3.) the structural loads in the tail section.

Also - The 262 was also supposed to 'hunt' in yaw at speeds above 400kts, increasing as speeds went higher. If that characteristic worsened (why would it cease?) then rudder loads in that same transition area would force more torsion on the fuse/tail connect area of the 262.

Now Soren, how fast do you think a cloud of debris can fly? and what substantiation from 'professional design team' comprised of aeros, structures and Stab/Control guys lead You to think it is 'doable'? You are an expert capable of making those judgments absent the data?

I have been out of the design biz for a long time - so perhaps you can enlighten me in the latest technology for aero analysis that predicts asymmetric loads in transonic flow conditions?? So that we can look at yaw and dutch roll initiation, get the combined rudder/elevator trim requirements and look at the incremental loads from those two?

Does your 'professional study' detail these conditions? Can you interpret the 'study'? Have you read the study?

A pure Aero Analysis might show that with enough power you could shove that beast past mach 1 - but a pure aero analysis would not include a structural analysis unless it was further modelled with the aero loads into something more sophisticated than NASTRAN or Stardyne. You have THAT report handy? 

Produce it please?

Show us the report Soren.


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## drgondog (Oct 18, 2008)

Soren said:


> I agree it wouldn't be the true TAS but rather an approximation of it. And yes AFAIK compressibility effects were taken into account as-well.
> 
> *And if it is an 'approximation' - how reliable is it?*
> 
> As for temperature, no idea mate, if so I would assume it needed to be punched in manually via observation.



A thermocouple inserted in the fuselage aft of the cockpit would serve. It would be easy to determine what the speed of sound would be at the altitude the 262 was flying - it would not be affected by compressibility effects.

Getting TAS is quite another issue altogether anywhere near .8-.9 M in those days... and therefore any reference to actual Mach based on 262 instruments would be 'suspect'


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## davparlr (Oct 18, 2008)

Soren said:


> Doesn't say, but the Me-262 had two air speed indicator needles, one listing IAS the other TAS so I suppose it is TAS.



Aircraft performance limitations are typically given in IAS/CAS, which closely reflect the aerodynamic forces on the aircraft. For pilots, TAS is mostly used for navigation purposes. TAS is also used in comparing absolute performance comparison between aircraft, as with this site.


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## drgondog (Oct 18, 2008)

davparlr said:


> Aircraft performance limitations are typically given in IAS/CAS, which closely reflect the aerodynamic forces on the aircraft. For pilots, TAS is mostly used for navigation purposes. TAS is also used in comparing absolute performance comparison between aircraft, as with this site.



Absolutely - the IAS also has to be coupled with knowledge of altitude in the case of these birds - and was similarly screwed up by compressibility effects anywhere near .8 M.


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## Soren (Oct 18, 2008)

Bill,

The study no doubt took in to account the structural integrity of the a/c, infact that is mentioned, otherwise it wouldn't be a serious study. However it was a serious in depth study Bill, not some amateur's go at trying to resolve some issue by assuming this and that.

And just because I don't have the report doesn't mean it isn't valid Bill, don't try to muddy the waters by suggesting such nonesense. I don't have to prove why the Me-262 could go supersonic in a dive, professional *aerodynamicists* have proven that it could by taking all aspects into account, otherwise it wouldn't be a serious study. So I am truly sorry Bill but I believe the professionals who took the time to study the issue in its entirety more than some hunch by a retired aero engineer.

So stop the twisting and turning and accept what the professionals have said on the subject, or are you suggesting you know better than them ? I aint.



> Also - The 262 was also supposed to 'hunt' in yaw at speeds above 400kts, increasing as speeds went higher. If that characteristic worsened (why would it cease?) then rudder loads in that same transition area would force more torsion on the fuse/tail connect area of the 262.



Only a few exhibited this behavior Bill, not all, which can be attributed to the varying degree of quality the a/c were being built to depending on which factory they came from.


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## Juha (Oct 18, 2008)

Soren
Delcyros, who has read the study wrote: “As I underlined above, the study only shows the possibility but concludes that it is well beyond probability that it really happened. Structural Issues (the Verwindungsbruch is mentioned here several times) are taken into consideration. The specific circumstances in the dive entry (low load and max. ceiling at specific speed are good, high load will render recovery in time problmatic), the high initial dive angle and structural issues make it very questionable that a normal -262 will survive the event.”

Compare it to your own comments for ex. Your #61
“It has been solidly confirmed by studies done in Germany that the Me-262 was perfectly capable of breaking the soundbarrier.”

And Mutke, who was a very ”green” Me 262 pilot at the time, still in his training phase, made his claim public only in 90s

Juha


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## Soren (Oct 18, 2008)

A normal Me-262 in 1945 wasn't of very good quality Juha, so obviously there would be structural issues. But a Me-262 built to the standards of those made in mid 44 would be perfectly capable of breaking the soundbarrier without breaking apart. However, and yes I read the report as-well, distortion of the wings and popped rivets are to be expected.

But as the report states even a "normal" Me-262 could break the sound barrier, but damage to the airframe was to be expected. Still it holds true that the a/c was perfectly capable of breaking the sound barrier, but it was no walk in the park and it was dangerous.

Btw, Mutke isn't the only Me-262 pilot to have claimed breaking the soundbarrier.


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## Soren (Oct 18, 2008)

Anyway the British claimed they reached 0.9 Mach with the Spitfire which is a propeller driven a/c with zero thrust at such speeds, while the Germans claim to have gone Mach 1 in a dive with a Jet fighter which not only was much cleaner but also had available a lot of thrust at such speeds.


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## drgondog (Oct 19, 2008)

Soren said:


> Bill,
> 
> The study no doubt took in to account the structural integrity of the a/c, infact that is mentioned, otherwise it wouldn't be a serious study. However it was a serious in depth study Bill, not some amateur's go at trying to resolve some issue by assuming this and that.
> 
> ...



Soren, are you the same guy that shouted everyone down on the superior quality of German manufacturing a year or so ago? 

For the sake of arguement, what are your facts on the quality of the 262 being built in 1945? Do you have manufacturing quality reports from Erding, etc? Where is your evidence of superior quality between factories? What were the standards for airframe acceptance? What components do you believe constituted sub quality with respect to Messerschmidt published standards? 

Where was the 'point of failure' for the 262 when it did fail in a dive? Can you link that to quality or Structural failure based on stresses beyond limit load design?

You are exceptionally slippery when you get cornered.

1.) you point to 'professionals' and the report as acceptable to you, but you fail to submit the report and/or specific quotes from that report which a.) state the 262 unequivocally can attain Mach 1 with no question regarding stability or structural issues, and b.) support the conclusions with the analytics.

2.) you launched into a BS claim regarding 'commonly used aero term of 'Lift Loading' in context of performance criteria - and claimed that Lift Loading is WL/Clmax and is a comparison of turn performance.

3.) You cite Mutke's report of exceeding Mach 1 based on his interpretation - but not substantiated nor evidence in fact from a third party - but you reject other claims by Brit tests regarding a Spit diving speed held under test conditions, or Encounter reports claiming '660 mph' dive in a Mustang. In other words you are selective in parsing statements until you find one you like - that then becomes your 'fact' foundation.

You can call me an amateur aero or structures guy if you wish. I have been out of the business for 30 years. But the ad hominem attack does nothing to bolster your own credentials or even provide a basis to attack mine. 

You are a funny guy Soren..


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## DerAdlerIstGelandet (Oct 19, 2008)

Interesting discussion so far. 

But I have to agree with Bill here and say:

Soren if you are going to claim something and site "professional sources" then you need to provide the sources. 

Now having said that:

What me and the other moderators said in the Panzer thread, applies to this thread as well. As soon as this thread gets out of hand, the thread will be closed and the effected parties will take an extended vacation.

We do not need any childish bullshit here.


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## FLYBOYJ (Oct 19, 2008)

Soren said:


> A normal Me-262 in 1945 wasn't of very good quality Juha, so obviously there would be structural issues.


Mirrioring what already been said.

For a statement like you you're going to have to show where the quality of latter model 262s were deficient enough to cause structural issues. I would agree that there was degradation across the board on all aircraft being built by Germany towards the end of the war, but having built several hundred aircraft and drones myself, its actually pretty hard to screw up the assembly of a structure when it is built in a jig, and I do now that all 262s were jig built. Unless there were deficiencies in sub assemblies, heat treating and processing of structural parts or some other core systemic deficiency, a few poorly driven rivets aren't going to make a difference in the long run unless they happen to be holding major components together, and again it would be highly suspect to try to attempt to put a finger on where and when something like that was to happen in the aircraft's production.


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## Soren (Oct 20, 2008)

Ok for the sake of preserving the interesting nature of this discussion I’m gonna ignore Bill’s insults and attempt at starting a mud throwing contest.

The sources for my claims are Mutke’s own description of what happened coupled with the findings of the study done in Germany in 1999. 

Ok you want me to provide the 1999 Study, well atm. I can’t because I don’t have it, I’ve made that clear multiple times by now. I first read it a couple of years back and saved it somewhere. 

But I am not the only one to draw attention to that study, Delcyros was the first IIRC and he also didn’t provide it for anyone to see, yet no one complained. However Bill insists I provide it for some reason, but only because he has run dry of arguments himself IMO. (Which is also the reason he finds it necessary to throw insults at me, which I am not going to pursue)

Moving on…

For the sake of simplicity let me summarize the arguments brought forth:

I say the Me-262 quite clearly broke the sound barrier because as Mutke explains the heavy vibrations and uncontrollable pitch down his a/c exhibited while in the transonic region suddenly seized and a smooth ride followed while still in the dive, after which he shut his engines and started to trim the tail plane to recover from the dive (The all moving tailplane is what allowed him to recover from the dive as shockwaves rendered the elevators ineffective), shortly after the vibrations started again. This to me is a clear sign that he went supersonic. And studies done in Germany in 1999 prove that it was possible for the Me-262 to go supersonic, but it was risky and damage to the a/c was almost assured, and depending on the quality of the workmanship of the airframe it could come apart in the attempt as-well. 

Further proof that the Me-262 either went supersonic or came extremely close to it is the British claims that the Spitfire, a propeller driven a/c, reached Mach 0.9 in dives. The claim is substantiated by the fact that the speeds were recorded to be viewed afterwards. The Spitfire featured no wing sweep and being a propeller driven a/c it had absolutely no thrust at such high speeds, so to explain why the a/c was capable of such a speed it is claimed that it is the unusually thin airfoil which gave the a/c its high Mach number. 

Keeping the above in mind it should be mentioned that the Me-262 not only featured a thinner wing than the Spitfire but also wing sweep, and even more crucial is the fact that the Me-262 is a Jet and thus has available a lot of thrust at high speeds. Furthermore the Me-262 is a much cleaner a/c than the Spitfire.

In level flight the average Me-262 achieved a top speed of Mach 0.77 to 0.79 at a height of 6km (The British established the top level speed to be 900 km/h in several recorded flights).

So there is absolutely no doubt in my mind that the Me-262, along with the Me-163 F-86 Sabre, broke the sound barrier before Chuck Yeager in his X-1 craft.


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## Soren (Oct 20, 2008)

> but you reject other claims by Brit tests regarding a Spit diving speed held under test conditions, or Encounter reports claiming '660 mph' dive in a Mustang.



Bill that is a lie, I never mentioned the Mustang, all I said was I doubt that the Spitfire ever reached Mach .9 in a dive, I think Mach .82 seems a lot more reasonable.

Fabricating stuff definitely doesn't bolster your own credentials Bill.


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## Soren (Oct 20, 2008)

FLYBOYJ said:


> Mirrioring what already been said.
> 
> For a statement like you you're going to have to show where the quality of latter model 262s were deficient enough to cause structural issues. I would agree that there was degradation across the board on all aircraft being built by Germany towards the end of the war, but having built several hundred aircraft and drones myself, its actually pretty hard to screw up the assembly of a structure when it is built in a jig, and I do now that all 262s were jig built. Unless there were deficiencies in sub assemblies, heat treating and processing of structural parts or some other core systemic deficiency, a few poorly driven rivets aren't going to make a difference in the long run unless they happen to be holding major components together, and again it would be highly suspect to try to attempt to put a finger on where and when something like that was to happen in the aircraft's production.



FLYBOYJ, 

The German industry was under a lot of stress as the war went on, having to finish a/c at increasing paste while proper materials and resources were in short supply and the factories were being bombed. All this resulted in that the Me-262's contructed in 1945 were subject to shabby workmanshipby comparison to those built in mid to late 1944. By 1945 all German a/c were being hurridly put together in order just to get 'something' in the air to counter the Allies, the Germans were desperate. The quality of the workmanship of the 109's built in 1945 was but a shadow of what it was a mere half a year earlier.


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## FLYBOYJ (Oct 20, 2008)

Soren said:


> FLYBOYJ,
> 
> The German industry was under a lot stress as the war went on, having to finish a/c at increasing paste while proper materials and resources were in short supply and the factories were being bombed. All this resulted in that the Me-262's contructed in 1945 were subject to shabby workmanshipby comparison to those built in mid to late 1944. By 1945 all German a/c were being hurridly put together in order just to get 'something' in the air to counter the Allies, the Germans were desperate.


Show me specifically where and how these aircraft were deficient or suspect to have structural integrity problems? What you said could be applied to just about any German aircraft of the period but to say their structural in integrity was suspect is far reaching unless you have facts. Poor workmanship in assembly would be noted (rivet flushness, gap and mismatch, rework of discrepancies, etc.) but that doesn't necessarily mean the aircraft will have structural problems.

Personally I believe the Me 262 "could have" gone super sonic *IF* the engines didn't flame out in the trans sonic range, *IF* the aircraft did hold together and *IF* the pilot did the right thing to recover so he didn't wind up as a statistic. There’s a lot more ifs tied to this so to me it’s possible but not probable and in the end I really doubt it happened and even if it did I also doubt the guy flying it would live through it. (And I don't believe Mutke actually went supersonic, close but not truly mach 1)

Bottom line, you could make a brick go supersonic if you put enough thrust behind it.


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## drgondog (Oct 20, 2008)

no further comment


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## kool kitty89 (Oct 20, 2008)

Moving on to a slightly different topic: Does anyone have info on the Me 262 HG-I's (the one actually flight tested) critical Mach number and control characteristics when this speed was reached?


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## red admiral (Oct 20, 2008)

The 004 has neither a convergent-divergent nozzle nor reheat and so the thrust massively drops off by Mach 1. Far more important is the fact that you're in a dive and gravity is pulling you earthwards - which is why a Spitfire can accelerate up to M0.94. 

The Me 262 had negligible wing sweep. The effect can be calculated by taking the Cosine of the sweep angle. This reduces the effective thickness by an entire 5% to give an effective thickness of 10.5%. This is a far cry from the 5% and 6% t/c for other high transonic aircraft (and most are much cleaner designs)



> Bottom line, you could make a brick go supersonic if you put enough thrust behind it.



Its called the Space Shuttle.


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## Juha (Oct 20, 2008)

Soren
I wonder how you can first try to proof a claim with a fact

Quote: “Further proof that the Me-262 either went supersonic or came extremely close to it is the British claims that the Spitfire, a propeller driven a/c, reached Mach 0.9 in dives. The claim is substantiated by the fact that the speeds were recorded to be viewed afterwards. The Spitfire featured no wing sweep and being a propeller driven a/c it had absolutely no thrust at such high speeds, so to explain why the a/c was capable of such a speed it is claimed that it is the unusually thin airfoil which gave the a/c its high Mach number.”

And then in the next message dispute the very same fact

Quote: “all I said was I doubt that the Spitfire ever reached Mach .9 in a dive, I think Mach .82 seems a lot more reasonable.”

After all drag raise is very steep after say Mach 0.75 (depending on a/c). So if Spitfire’s max was Mach 0.82 how that support Mutke’s claim? The question is only rhetorical one. 

And as Bell X-1 showed, wing sweep wasn’t mandatory to high transonic/supersonic speeds.

Juha


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## drgondog (Oct 20, 2008)

Juha said:


> Soren
> I wonder how you can first try to proof a claim with a fact
> 
> Quote: “Further proof that the Me-262 either went supersonic or came extremely close to it is the British claims that the Spitfire, a propeller driven a/c, reached Mach 0.9 in dives. The claim is substantiated by the fact that the speeds were recorded to be viewed afterwards. The Spitfire featured no wing sweep and being a propeller driven a/c it had absolutely no thrust at such high speeds, so to explain why the a/c was capable of such a speed it is claimed that it is the unusually thin airfoil which gave the a/c its high Mach number.”
> ...



Pretty good summary Juha. The other wildcard is that apparently the Spit did not suffer a 'pitch down' moment coefficient as it went transonic over the wing - unlike the 262. 

Nothing like becoming a cloud of aluminum fragments to slow one's progress toward Mach 1.


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## Soren (Oct 20, 2008)

FLYBOYJ said:


> Show me specifically where and how these aircraft were deficient or suspect to have structural integrity problems? What you said could be applied to just about any German aircraft of the period but to say their structural in integrity was suspect is far reaching unless you have facts. Poor workmanship in assembly would be noted (rivet flushness, gap and mismatch, rework of discrepancies, etc.) but that doesn't necessarily mean the aircraft will have structural problems.



Well as you know at close to Mach 1 even small defeciencies can be fatal. Lets say a panel comes off at Mach 0.85 because of a small gap made in assembly, well that could cause the whole a/c to come apart.

The pace at which a/c were being contructed in 1945 as well as, and no less, the circumstances under which they were made, enevitably caused a lot of quality issues. But to make matters even worse the LW, in order to get enough a/c in the air, had to significantly lower their quality acceptance demands. Hans Fey also notes the lower quality acceptance demands and differing workmanship between a/c in the report on the site I referenced earlier.

Infact by 1945 Hungarian built 109's were considered to be of much better quality than German built ones. 



> Bottom line, you could make a brick go supersonic if you put enough thrust behind it.



Yes, but will it stay together ?


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## Soren (Oct 20, 2008)

Juha said:


> Soren
> I wonder how you can first try to proof a claim with a fact
> 
> Quote: “Further proof that the Me-262 either went supersonic or came extremely close to it is the British claims that the Spitfire, a propeller driven a/c, reached Mach 0.9 in dives. The claim is substantiated by the fact that the speeds were recorded to be viewed afterwards. The Spitfire featured no wing sweep and being a propeller driven a/c it had absolutely no thrust at such high speeds, so to explain why the a/c was capable of such a speed it is claimed that it is the unusually thin airfoil which gave the a/c its high Mach number.”
> ...



I was presenting arguments from all parties Juha. 

I was making the point that how can people who support that the Spitfire reached Mach 0.9 in a dive not support that a much cleaner a/c, with a thinner wing, with sweep (Every little helps), a Jet infact, reached Mach 1 in a dive?



> After all drag raise is very steep after say Mach 0.75 (depending on a/c). So if Spitfire’s max was Mach 0.82 how that support Mutke’s claim? The question is only rhetorical one.



Well it supports it a lot in my mind as the Me-262 was over 200 km/h faster in level flight. 



> And as Bell X-1 showed, wing sweep wasn’t mandatory to high transonic/supersonic speeds.
> Juha



True, but every bit helps Juha. 

PS: The X-1 barely had any wings, more like fins


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## FLYBOYJ (Oct 20, 2008)

Soren said:


> Well as you know at close to Mach 1 even small defeciencies can be fatal. Lets say a panel comes off at Mach 0.85 because of a small gap made in assembly, well that could cause the whole a/c to come apart.
> 
> The pace at which a/c were being contructed in 1945 as well as, and no less, the circumstances under which they were made, caused some a lot of quality issues. But to make matters even worse the LW, in order to get enough a/c in the air, had to significantly lower their quality acceptance demands. Hans Fey also notes the lower quality acceptance demands and differing workmanship between a/c in the report on the site I referenced earlier.
> 
> Infact by 1945 Hungarian built 109's were considered to be of much better quality than German built ones.



Do you have any evidence of any 262s coming apart during normal combat, affected by the lower quality standards? The bottom line is you're only speculating on something that may or may not existed. I've assembled and worked on MiG-15s from USSR, Poland and China and I could see the difference in the quality of the aircraft, but I could also say despite the lower quality of one to another there's going to be little or no difference the way each one will fly.



Soren said:


> Yes, but will it stay together ?


I'd give it about the same odds as a 262 or any other aircraft where the designer says not to exceed critical mach number - BTW, the MiG-15 was in the same boat - Could it exceed mach 1? Possibly, but the odds are the pilot won't live to tell about it


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## Soren (Oct 20, 2008)

FLYBOYJ said:


> Do you have any evidence of any 262s coming apart during normal combat, affected by the lower quality standards?



Infact yes I have, Prof. Doetch's envestigations done in 1944 which concluded that many of the Me-262's lost in combat due to unexpectingly falling apart in dives were because of poor quality workmanship on some ships.



> The bottom line is you're only speculating on something that may or may not existed.



No as envestigations done in 1944 prove that there were infact quality issues which caused fatal crashes than I aint really speculating just citing.



> I've assembled and worked on MiG-15s from USSR, Poland and China and I could see the difference in the quality of the aircraft, but I could also say despite the lower quality of one to another there's going to be little or no difference the way each one will fly.



MIG production facilities weren't being bombed, manned by slave labor or lacked any resources or materials. 




> I'd give it about the same odds as a 262 or any other aircraft where the designer says not to exceed critical mach number



First of all Willy wasn't the designer, and secondly all that was concluded was that at Mach .86 the Me-262 would enter an untrollable pitch down dive, the increasing negative G-forces eventually breaking the a/c apart.



> - BTW, the MiG-15 was in the same boat - Could it exceed mach 1? Possibly, but the odds are the pilot won't live to tell about it



Yet the F-86 Sabre did it, regularly..


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## Soren (Oct 20, 2008)

drgondog said:


> Pretty good summary Juha. The other wildcard is that apparently the Spit did not suffer a 'pitch down' moment coefficient as it went transonic over the wing - unlike the 262.



That is probably because the Spitfire never went fast enough for it to happen. There's a reason the all moving tail-plane was such an important feature. 

_"The aircraft's design introduced many innovations which are still used on today's supersonic aircraft. The single most important development was the all-moving tailplane, giving extra control to counteract the Mach tuck which allowed control to be maintained to and beyond supersonic speeds. This was wind-tunnel tested at Mach 0.86 in 1944 in the UK.[6] In the immediate postwar era new data from captured German records suggested that major savings in drag could be had through a variety of means such as swept wings, and Director of Scientific Research, Sir Ben Lockspeiser, decided to cancel the project in light of this new information. Later experimentation with the Miles M.52 design proved that the aircraft would indeed have broken the sound barrier, with an unpiloted 3/10 scale replica of the M.52 achieving Mach 1.5 in October 1948."_


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## Waynos (Oct 20, 2008)

The fact that the Spitfire was not a jet doesn't really prove anything wrt the 262. It is after all a matter of record that the Spitfire dived faster than the Meteor, Vampire and P-80, all jets. It only proves that the Spitfire could dive at an exceptional speed for its class of aircraft.

_secondly all that was concluded was that at Mach .86 the Me-262 would enter an untrollable pitch down dive, the increasing negative G-forces eventually breaking the a/c apart.

_

isn't that the point?


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## FLYBOYJ (Oct 20, 2008)

Soren said:


> Infact yes I have, Prof. Doetch's envestigations done in 1944 which concluded that many of the Me-262's lost in combat due to unexpectingly falling apart in dives were because of poor quality workmanship on some ships.


So what makes you believe that those built in 1944 with "some" flaws had the same chances of coming apart as those built later? Do have serial numbers and dates they were produced? Lot numbers, etc?




Soren said:


> No as envestigations done in 1944 prove that there were infact quality issues which caused fatal crashes than I aint really speculating just citing.


Oh so if it happened in 44' then some of those incidents "could of" been at the front of the production run, when the quality was higher?



Soren said:


> MIG production facilities weren't being bombed, manned by slave labor or lacked any resources or materials.


Slave labor yes as well as unqualified labor as well.



Soren said:


> Do I have to repeat that Willy wasn't the designer ?


No he wasn't but he was the head of the design team and the buck stopped with him. In the book "Arrow to the future" by Walter Boyne there is a very detailed organization chart of how he and his design team interacted and the bottom line here is a limitation was placed on the airframe - Willy would of had the final say taking into consideration input from his aerodynamicists as well as design and stress engineers. On page 108 of the book it list "Prof. Messerschmitt as chief engineer with Fronklich, Rethel, reporting directly to him and Voigt underneath Williy



Soren said:


> Yet the F-86 Sabre did it, regularly..



And it did - and those who designed it knew it could do so with ease including the chief test pilot who proceeded to do so days before Yeager did, but the only proof of that is the dozens of people who heard the "boom." Without witnesses and telemetry equipment it is speculation, just like Mutke's flight.


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## Waynos (Oct 20, 2008)

Slight digression here but wasn't the first British pilot to exceed Mach 1 Roland Beaumont in a USAF F-86? Albeit unofficially. I'm sure I read that somewhere.


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## Waynos (Oct 20, 2008)

The MiG 15 had its tail mounted near the top of a very large fin, surely a major flutter problem when nearing mach unity? When they built a supersonic fighter MiG moved the tail to ther rear fuselage, like it was on the F-86


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## drgondog (Oct 20, 2008)

Soren said:


> Well as you know at close to Mach 1 even small defeciencies can be fatal. Lets say a panel comes off at Mach 0.85 because of a small gap made in assembly, well that could cause the whole a/c to come apart.
> 
> *If you think a 1/4" gap between butt joint panels would make a difference at Mach 1, much less Mach 2 - you have never seena Mig 21 up close.  'gap's might make a difference in drag if those panels were immersed in a boundary layer but you wouldn't notice it in turbulent region.
> 
> ...



That HAS been the question Soren with zero substantiation that yes, the me 262 as designed and built, will in fact take the aerodynamic loads associated with .89- 1.0 Mach.. 

and that the pitch down issue at .83 to .86 was somehow solved, that the associated bending and torsion forces that would be experienced attempting to control high speed yaw (on Rudder) and pitch (slab tail with very high associated stick forces) were 'not a problem' and shown to be so with rigorous stability and control analysis coupled with professional aero analysis and advanced structural solutions taking all that into account..

Why isn't the logic and fact base so compelling that anyone (not even Everyone) agrees with you.. Messerschmidt didn't, the RAF and USAAF Test pilots didn't, I have seen zero LW Test pilots giving testimony in 1944-1945 when they were actually flown, the Russians quit flying it past .86 after barely surviving the experience, the Czechs (to my knowledge) never pushed it past .84. THERE is a HUGE drag rise between .82 and .9 - much less 1.0 assuming stability and control issues were ever solved.

The modern day builders (Stormbird) placard the airframe at 540kts at SL (~.82M) despite a far superior engine, improved internal structure and internal/extenal quality. Why?

You think you have made your speculative case?


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## drgondog (Oct 20, 2008)

Waynos said:


> The MiG 15 had its tail mounted near the top of a very large fin, surely a major flutter problem when nearing mach unity? When they built a supersonic fighter MiG moved the tail to ther rear fuselage, like it was on the F-86



I understood the primary problem for the Mig 15/17 was also Pitch down in the transonic as the shock flow moved the CP to 50% chord region without enough deflection in the elevator to fully compensate.. but it has been a long time since I even thought about that so I could be wrong.

Flutter is almost always an issue when a control surface is immersed in a turbulent wake - or the natural frequency of the control assembly is close to the input forces/frequency of the airflow and vortices being shed upstream.


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## FLYBOYJ (Oct 20, 2008)

Waynos said:


> Slight digression here but wasn't the first British pilot to exceed Mach 1 Roland Beaumont in a USAF F-86? Albeit unofficially. I'm sure I read that somewhere.


I believe you are correct



Waynos said:


> The MiG 15 had its tail mounted near the top of a very large fin, surely a major flutter problem when nearing mach unity? When they built a supersonic fighter MiG moved the tail to ther rear fuselage, like it was on the F-86


That was done, but I think the non-area rule fuselage and the wing fences also played havoc at transonic speeds as well.


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## Waynos (Oct 20, 2008)

Yes, quite so. I know that the MiG 19 prototype had a high tail like its predecessors and that it was very quickly changed, I'll nip off to see if I can find out why.


Apparently the reason was spin recovery, rather than flutter.


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## Soren (Oct 20, 2008)

> You said earlier that 'only a few' 262s exhibited a tendency to hunt' - *which is at variance with all the 262s tested by USAAF after the war.* You stated those were 'quality issues'?? also. With respect to what?



Do you have a source for that claim Bill, and how many is *all* ??

I have a source for the fact that only a few Me262's exhibited the tendency to hunt: Me-262 test pilot Hans Fey, Allied Report, the site I referenced, written in big bold black letters.


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## Soren (Oct 20, 2008)

> If you think a 1/4" gap between butt joint panels would make a difference at Mach 1, much less Mach 2 - you have never seena Mig 21 up close. 'gap's might make a difference in drag if those panels were immersed in a boundary layer but you wouldn't notice it in turbulent region.



Lets say the left gun cover comes off at Mach 0.86, that'd be pretty serious Bill. If wind is allowed inside a gap it will eventually, with increases in speed, increase the gap and lift the entire panel off.


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## FLYBOYJ (Oct 20, 2008)

Soren said:


> Lets say the left gun cover comes off at Mach 0.86, that'd be pretty serious Bill. If wind is allowed inside a gap it will eventually, with increases in speed, increase the gap and lift the entire panel off.


Ive seen access covers come off F-4s that went way more than mach 1 - most of the time nothing happened.

Gaps in structure could be detrimental depending where they are located. Again all this is highly subjective.


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## pbfoot (Oct 20, 2008)

FLYBOYJ said:


> Ive seen access covers come off F-4s that went way more than mach 1 - most of the time nothing happened.
> 
> Gaps in structure could be detrimental depending where they are located. Again all this is highly subjective.


ditto but on 104's


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## drgondog (Oct 20, 2008)

Soren said:


> Lets say the left gun cover comes off at Mach 0.86, that'd be pretty serious Bill. If wind is allowed inside a gap it will eventually, with increases in speed, increase the gap and lift the entire panel off.



And 1.) you know this how?, and 2.) so what?

It would be more serious if the nose tuck kept putting extraordinary forces on the tail

I'm not saying it doesn't happen or it doesn't have consequences - but I believe this round robin has been all about Mach 1 in an Me 262. Example please of real world 'actual's rather than Soren 'hypotheticals'?


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## DerAdlerIstGelandet (Oct 21, 2008)

Soren said:


> Well as you know at close to Mach 1 even small defeciencies can be fatal. Lets say a panel comes off at Mach 0.85 because of a small gap made in assembly, well that could cause the whole a/c to come apart.



That depends on the panel Soren. If a structural panel comes off, possibly it will make the aircraft come apart (possibly, not certainly).

Just any old panel though, probably not.



Soren said:


> Lets say the left gun cover comes off at Mach 0.86, that'd be pretty serious Bill. If wind is allowed inside a gap it will eventually, with increases in speed, increase the gap and lift the entire panel off.



Again Soren, not nessessarily. Just because a panel comes off in flight is not neccessarily going to cause anything.

Do you know the difference between "any old" panel and a structural panel?


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## claidemore (Oct 21, 2008)

One of the problems with Mutkes story, is confusion about when he reduced engine power and flamed out. The way it is written in some sources, one could mistakenly assume he reduced engine power after the plane stopped buffeting and had smoothed out. Question is, why would you do that? If the plane has stopped buffeting, and is flying smoothly, why do anything? 

Others sources make it clear that he reduced power when the plane initially started buffetting. 

Not all sources mention the few seconds when the 262 supposedly stopped shaking then resumed, and even if that happened, it is not conclusive proof of supersonic flight. It is only proof that the plane stopped shaking, for all we know it could have reduced speed enough to stop shaking (after engine flameout), then increased speed because of the nose down pitch, until Mutke finally managed to trim it out. In fact that is the far more likely chain of events, one that all the other evidence would support. 

Another question is; if Mutke knew the speedometer was stuck at 1100 kmh, and reported it, was there nobody amongst all those jet jocks at his airfield that knew what the speed of sound was? Why didn't somebody say "Holy freeolies Batman, you must have broke the sound barrier!" Another discrepancy is that some sources say he figured out what he might have done after Yeagers flight, (1947) and other sources say he didn't figure it out till 1989. 

Since this happened in April 1945, when was this particular 262 built? If we follow the theory that late war 262's were of inferior build quality, how could this one survive going supersonic? 

Also, if Mutkes engines flamed out, there was no more thrust, mooting the point about zero thrust from the prop driven Spitfire. We should note that the Spit XI was a very clean plane, polished finish, gaps sealed and smoothed out, no guns, no ammo bay bulges, no armored windscreen etc.

We should also remember that the 262 did not have a true 'swept' wing, (18.5 degrees) and that fact is pointed out in almost every reference on the plane. A proposed sweep of 45 degrees (HG III)had a projected speed of Mach .96. Mutkes plane is reported as having structural damage to the wing, so not only was there danger of tail damage, but wing failure as well.

As for the study done in 1999, every plane is designed by experts in aerodynamics, and nearly every plane exhibits behaviors that the designers didn't anticipate and have to make corrections for. Unless someone actually puts a 262 through a test program and proves with instruments that it can go supersonic,the 1999 study is at best theoretical.


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## KrazyKraut (Oct 21, 2008)

German fighter aircraft near the end of WW2 were "in general" of lower quality. That doesn't mean that every single example was. So this is no proof or indication whatsoever. If you want to disprove or prove anything, resorting to even more highly speculative argumentation like you did in that entire post doesn't help anything.

The 1999 study may be theoretical but at least it's based on facts and figures not suggestion.


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## kool kitty89 (Oct 21, 2008)

red admiral said:


> The 004 has neither a convergent-divergent nozzle nor reheat and so the thrust massively drops off by Mach 1. Far more important is the fact that you're in a dive and gravity is pulling you earthwards - which is why a Spitfire can accelerate up to M0.94.
> 
> The Me 262 had negligible wing sweep. The effect can be calculated by taking the Cosine of the sweep angle. This reduces the effective thickness by an entire 5% to give an effective thickness of 10.5%. This is a far cry from the 5% and 6% t/c for other high transonic aircraft (and most are much cleaner designs)



Actuall, at the wing center section (inboard of the nacelles) the Me 262 has 0 sweep, just a LE extention to match the swept outboard sections. (so these sections would be the full 11% chord) Additionally, the root had the max thickness at 35% chord rather than 40% on the outboard sections. (the outboard section tapered from 11% at 40% chord to 9% at 40% chord, not taking sweep into account)




Soren said:


> PS: The X-1 barely had any wings, more like fins



Actually, for its size, the X-1's wing was rather substancial, and fairly thick all things considered. At 10% thickness, the XS-1 (X-1-1) had a thicker wing than the F-86 (9% at root) without even taking sweep into account. The later X-1-2 and X-1A/B/D had 8% thick wings. Now, the F-104 had fins! 

On straight winged transsonic aircraft, 10% thickness/chord ratio seems to be the max for the wing. The Skystreak, F-94C, and CF-100 all having 10% TR airfoils (the CF-100's not even being a laminar flow section, but a conventional NACA 0010) and all three were capable of diving through Mach 1.


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## kool kitty89 (Oct 21, 2008)

Given the airfoils used on the MiG-15 and 17, they should have significantly high critical Mach numbers to safely get to Mach 1. However, it would seem the limitig factor is the tail configuration, the horizontal stabilizer/elevator losing control ability near Mcrit. It would seem that neither featured a trimmable stabilizer or boosted elevator controls, let alone "all flying" tail. 
I don't think the fences were really an issue though, being features of several supersonic aircraft many Soviet, and the F-102.



The F-86's boosted elevator seems to have been fully functional up through Mach 1, with no mention of trim being used to recover from supersonic dives in several accounts I've heard and read. (including Welch's, and prior to the F86E the Sabre didn't feature an all flying tail, but a boosted elevator with a fully trimmable tailplane)


The MiG's lack of boosted alevator controls also hampered maneuverability at high speed.


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## Soren (Oct 21, 2008)

There's is no confusion regarding when Mutke shut his engines Claidemore, he shut them down after entering smooth flight as he regained control, it all went really quick. You should read Mutke's first hand account, there he explains in detail what happened.

He had entered a dive at full speed from an altitude of roughly 12,000m when suddenly his a/c began to shake violently, his airspeed indicator stuck against 1,100 km/h. He tried to recover by pulling back on the stick but the a/c just kept increasing the dive angle, he had no elevator control. Then suddenly all the vibrations stopped and a smooth 10 second ride followed, immidiately he shut the engines and started trimming the tailplane, and as the a/c started to recover the vibrations started again unil finally he leveled out at 8,300m.


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## kool kitty89 (Oct 21, 2008)

Soren, do you have a link to Mutke's story?

The previously mentioned page on luftarchiv.de no longer seems to exist: http://mach1.luftarchiv.de/mach1.htm


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## Soren (Oct 21, 2008)

That's the one I was going to link KK. Didn't it work just a couple of days ago ?


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## Soren (Oct 21, 2008)

drgondog said:


> And 1.) you know this how?, and 2.) so what?



Bill if a panel like the gun cover were to be ripped off a Me-262 at Mach .85 then it can only be serious. Hae you seen how big that panel is and where it is located ?? 



> It would be more serious if the nose tuck kept putting extraordinary forces on the tail



Again only a few exhibited this behavior.



> I'm not saying it doesn't happen or it doesn't have consequences - but I believe this round robin has been all about Mach 1 in an Me 262. Example please of real world 'actual's rather than Soren 'hypotheticals'?



The flight wasn't recorded Bill, so it's a matter of opinion wether one believes the Me-262 went supersonic or not, different arguments popping up in support of both scenarios.


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## Juha (Oct 21, 2008)

Soren
Quote: ” I was presenting arguments from all parties Juha.”

Now I understand that presenting arguments from all parties means presenting arguments for and against something, not that one tries to proof one’s own POV by presenting arguments that one him/herself doesn’t believe. 

Quote: “Well it supports it a lot in my mind as the Me-262 was over 200 km/h faster in level flight.”

Now IMHO it’s rather well known fact that at least in 40s the level speed wasn’t a very reliable indicator for the max Mach number possible for certain a/c. Think for ex P-47 and Spitfire XI. And putting a jet engine on a/c not necessary helped either see for ex Saab J 21A vs 21R. Putting a jet engine into J21 increased level speed but not the max Mach number. And see Waynos message #157 for further info.

Quote:” The X-1 barely had any wings, more like fins”

Now IMHO X-1 clearly had wings.

Juha

On Mutke’s story, to me as an historian the greatest problem is, why to wait 50 years before tell it. He would not be the first one whose stories got better with time. In the end it’s a question of what we believe. To me his story is possible but not probable, too many things had to go just right by chance, but of course there is the possibility that he was very lucky.

Juha


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## KrazyKraut (Oct 21, 2008)

I have no doubt that his account is true. When it was made public is of little relevance to me. The man led a life outside of this stuff and just because WE argue about whether or not lift loading is a relevant or valid measure does not mean every other person in the world cares.

I have talked to veterans of the Panzer force and they didn't even know half the subtypes or specifications. They simply didn't care. Rall himself made several mistakes in interviews about the Bf 109. Does that make him less credible?

The question to me is not whether his account is true. The question is if the evidence is enough to conclusively say that the man broke the sound barrier. Which it is imo not. The symptoms he described also occur when an aircraft nears the sound barrier or can be attributed to the actions he took. So I agree with you that while it is possible he broke the sound barrier, there is no conclusive evidence that he wasn't just close to it.


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## claidemore (Oct 21, 2008)

Krazykraut: Your conclusions are pretty much the same as those reached by me with my 'speculative arguments'. 
"Eliminate the unlikely and unprobable and what remains is the truth." As you pointed out, there isn't much evidence, so we have to use a little logic and deductive reasoning.


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## drgondog (Oct 21, 2008)

Soren said:


> Bill if a panel like the gun cover were to be ripped off a Me-262 at Mach .85 then it can only be serious. Hae you seen how big that panel is and where it is located ??
> 
> *Soren - that whole 'what if' had zero to do with Mutke's account, had zero to do with lending credibility to German QA issues relative to the Me 262.
> 
> ...




I think you have stated before that it is UNQUESTIONABLE that the Me 262 could achieve Mach 1. You cited the report by PROFESSIONAL AERODYNAMICISTS and Mutke to support that thesis. Are you backing away from the assertion?

I have asked for specific references in that Report by someone who has read it and understands the issues encountered at .82-.86 M, with regard to possible yaw issues, pitching moment issues in transonic cp change, structural analysis with the aero loads imposed on the airframe. You aren't that person.


Further, to be credible the Report must TAKE INTO CONSIDERATION the Yaw and Pitch issues, the details to support structural integrity with those assumed loads - and a sound thesis for discussiong post .86M speeds (and loads) all the way through Mach 1 to show that those (and other heretofore unknown) issues did not resurface.

But I get You... and Mutke. I really am interested in facts, but still I get You and your opinions - not supported by facts but supposition, speculation, reference to a report by Professionals - but no 'meat'... All the issues and more I haven't even thought of would have to be addressed, modelled and presented to be a Professional Study.

I KNOW the flight (Mutke) wasn't recorded. Lindner's were. I KNOW what the state of the art was in Instrumentation as well as predictive flight mechanics for transonic conditions in 1945. ZILCH. 

I KNOW what the art (Flight Mechanics, Aerodynamics, Aeroelasticity and airframe structures analytics) was capable of in the 1950's and 60's because that was the foundation for Aero education when I got my degrees. It STILL SUCKED relative to predictive flight mechanics. It is much better today depending on the tools available and the references.

On the 'references' and the Report - I would be very curious to know exactly which additional (other than aerodynamic and stability/control models) advanced analytical tools were used to perform the aeroelastic and structures analysis. To get a MODEL, you would have to have access to a.) the old drawings - complete package with all detail parts, assemblies and installations, specs on bolts, rivets, etc, skin thickness, rivet spacing, castings/forgings and heat treat specs, and b.) most desirable but not mandatory if the complete drawing dwg pkg is available, would be the structural analysis as a place to start. 

For example, If I had the structures analysis I would look at the entire tail section and fuse attach points to see what was near 'ultimate' stress at 1.5 Design Limit at which airspeed. I would be curious to the linking aero analysis which drove the pressure distribution predictions leading to those loads.

If any of that exists in the Professional report - would you know it and more importantly be able to follow the analysis? If so, please present it, or provide a reference to read or order it - or simply acknowledge that you are dealing from speculation and a belief system that I don't subscribe to and we can agree to disagree?


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## DerAdlerIstGelandet (Oct 21, 2008)

Soren said:


> Bill if a panel like the gun cover were to be ripped off a Me-262 at Mach .85 then it can only be serious. Hae you seen how big that panel is and where it is located ??



Again Soren:

No not necessarily. Only if it were a structural panel, and then it still might not happen.

Any normal panel (no matter what size it is) is not necessarily and probably not going to do anything.

Do you know the difference between a *structural* panel and a normal old access panel or cover panel?


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## drgondog (Oct 21, 2008)

KrazyKraut said:


> I have no doubt that his account is true.
> 
> *I have doubts about his interpretations. Instruments weren't reliable regarding True airspeed in the transonic to supersonic regime. The whole transonic shockwave and relocation of center of pressure aftward was little known and less understood. Schlierran photography was in its infancy.*
> 
> The question is if the evidence is enough to conclusively say that the man broke the sound barrier. Which it is imo not. The symptoms he described also occur when an aircraft nears the sound barrier or can be attributed to the actions he took. So I agree with you that while it is possible he broke the sound barrier, there is no conclusive evidence that he wasn't just close to it.



Actually the symptoms he described were completely consistent with the onset of compressibility over the Me 262 wing, as well as huge stick forces as the true airspeed progressed along the .82+ range, as well as the final desparate step of taking one hand off the stick to retard the throttle.

The first question that always to come to mind is about the TAS. If Lindner said the highest he ever took it was to 1004 Kph (calibrated) what was the IAS? I can't find a reference.

The second question that comes to mind is his recollection of sequences. The sequence of nose down, accelerate, experience increasing buffeting and increased stick forces during pitch down, retarding throttle, reducing speed and gaining manageable stick forces are all part of the Me 262 dive recounts.

His apparent recollection of 'reducing throttle' then vibration abatement for a time as he is pulling out, then increasing vibration certainly dovetails to a normal recovery from .85+ M but in no way substantiates Mach 1. 

Examining the possibilities 

So, at 1100 TAS @ 40K = 593 kts = 1.03M Not possible as this was max ceiling of the Me 262.

@ 30 K = 1100 TAS = 593 kts = 1.006 M
@ 20 K = 1100 TAS = 593 kts = .96 M
@ 13 K = 1100 TAS = 593 kts = .93 M

Lindner never exceeds 1004 m/[email protected] 13000 feet = 541 kts = .858 M which was calibrated apparently by 70 separate pressure sensors and then further measured against known distances on the deck..

Willy M. sets placard at .84 for not to exceed but even that is an unclear reference to IAS.

Back to your point (and Claidmore's, and Mine). 

There are no facts to support actual speed > .86 Mach. There is a wide body of evidence to support dire consequences above .86 Mach as well as several crashes during dive tests. 

Even the much discussed Me 262 Study/Professional Report" is not in evidence with respect to boundary conditions established for an analytical approach to speculate on the feasibility, nor the supporting caveats relative to structures or flight mechanics..

We can say the same thing for Welsh, even though there are witnesses to a 'boom' that the witnesses believed to be a supersonic shock wave.

Yeager's event was monitored and recorded and validated and repeated.

Is there any more in the way of evidence or facts that hasn't been exhausted?


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## kool kitty89 (Oct 21, 2008)

Soren said:


> Quote:
> 
> 
> > It would be more serious if the nose tuck kept putting extraordinary forces on the tail
> ...



I think he misspoke here Bill, since Soren seems to be responding to the snaking issue again, while you were commenting on the pitch-down behavior at Mcrit. (something Soren hasn't disputed)



> The flight wasn't recorded Bill, so it's a matter of opinion whether one believes the Me-262 went supersonic or not, different arguments popping up in support of both scenarios



And I don't think Soren is contradicting himself here. He's saying we can't know for sure if Mutke's Me 262 reached Mach 1 and it really depends on what you want to believe.

However, I don't think he's questioning the Me 262's ability to reach Mach 1 under the right circumstances.


I personally think Mutke may have possibly done it, but it's unlikely. (there's no way to be sure) But I do think the Me 262 was capable of reaching Mach 1 in the right circumstances. (though probably not without serious warping to the airframe)

It should be noted that Mutke's aircraft was scrapped due to the damage resulting from this event.



Also, I think the Me 262's CAS reading would still be exaggerated. (with TAS probably being ~910-920 km/h when the CAS indicator maxed out)

The IAS reading would be interesting as it would still be giving a reading when the CAS needle was maxed out.


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## Erich (Oct 21, 2008)

Mütkes interview after the accidental dive is on the net on several spots, noteworthy is Bert Hartmanns luftwaffearchiv. I wrote Guido years ago and out of this event feel he truly did so in the dive, not on the level. you can say what you want but the flight was all recorded for the groundtechs and evaluators galore his 262 was nearly torn apart under his own admission to me


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## kool kitty89 (Oct 21, 2008)

I agree Erich, I believe his story, but I'm not sure (one way or the other) if he actually broke the sound barrier, probably alt least made it to Mach ~.99 (where his engines would have stalled) which obviously overstressed the a/c from the excessive buffeting and aerodynamic loads.

The page on luftarchive.de unfortunately no longer seems to exist as I mentioned on the last page. Any other links to his story?


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## kool kitty89 (Oct 21, 2008)

Another interesting note on IAS speeds in similar conditions is that according to: The Amazing George Welch: Part two

The IAS during Welch's dive was in the high 400 mph to low 500 mph range, peaking at ~520 mph when he pulled out at 25,000 ft. (giving an "uncorrected TAS" of 720 mph -1,160 km/h- which would be ~1.04 Mach) How would the accuracy of the XP-86's instrumentation of 1947 compare to the Me 262's?


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## drgondog (Oct 21, 2008)

kool kitty89 said:


> I think he misspoke here Bill, since Soren seems to be responding to the snaking issue again, while you were commenting on the pitch-down behavior at Mcrit. (something Soren hasn't disputed)
> 
> *I was commenting on both. Disputing the 'snaking/hunt' comments by the USAAF test flights on two airplanes is difficult either way. On one hand you need a specific comment from the LW test pilots saying the 262 was completely steady or assume it occurred but wasn't particularly noticeable. I noted in the the USAAF reports that directional stability was a frequent line item to check off. An example is all versions of the Mustang*
> 
> ...



I honestly don't know what the 'peg' is for the 262 airspeed indicator. Lindner said the Mach meter didn't work and that true airspeed had to be calibrated after the tests from the pressure recordings filmed during test flights.


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## drgondog (Oct 21, 2008)

Erich said:


> Mütkes interview after the accidental dive is on the net on several spots, noteworthy is Bert Hartmanns luftwaffearchiv. I wrote Guido years ago and out of this event feel he truly did so in the dive, not on the level. you can say what you want but the flight was all recorded for the groundtechs and evaluators galore his 262 was nearly torn apart under his own admission to me



Erich - I don't presume he was lying about his impressions. 

If the flight was recorded where are either the data or the tech reports after analyzing the data? If Willy M, or Lindner were aware of near to actual Mach 1 why didn't they report it it? Why would Messerschmidt keep this confidential - his greatest achievement?

You couldn't convince Deacon Priest that he wasn't doing 620mph indicated airspeed chasing a 109 in his Mustang until after he got his aero degree several years after the war. My old man would cackle like a hen when Deac had a few scotches and recalled the Nov 2 mission.

The archives are full of 600+ mph recounts with trimming required to pull out in time.

No way any of those Mustangs were doing .85 mach with a combat config - the instruments said it and the damage implied it - but it didn't happen. I buy that the late model Spit exceeded .85 because of the wing - but I don't know if I believe .9 either... 

and then for the 262, with those stupid nacelles buried under the wing with all the implied inlet potential issues, a relatively fat wing, potential wing-body-nacelle interference in the transonic range and a pitch down phenomena that should have no relief until actual supersonic flight is achieved - leaves a lot of unknowns between .86 M and 1.0.

Unless and until the actual data surfaces with cross correlation to corroborate the claim - I just don't buy it.


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## FLYBOYJ (Oct 21, 2008)

kool kitty89 said:


> I agree Erich, I believe his story, but I'm not sure (one way or the other) if he actually broke the sound barrier, probably alt least made it to Mach ~.99 (where his engines would have stalled) which obviously overstressed the a/c from the excessive buffeting and aerodynamic loads.


My belief as well.....


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## Soren (Oct 22, 2008)

DerAdlerIstGelandet said:


> Again Soren:
> 
> No not necessarily. Only if it were a structural panel, and then it still might not happen.



Only ? Adler the gun cover panel on the Me-262 was large and if torn away would create a very large gap in the nose and as-well as a large blunt area directly facing the airstream.









> Any normal panel (no matter what size it is) is not necessarily and probably not going to do anything.



Perhaps not, but it depends alot on its position compared to the incoming airstream.



> Do you know the difference between a *structural* panel and a normal old access panel or cover panel?



Absolutely, but like I said much depends on its position in regards to how dangerous it is to loose it midflight.


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## Soren (Oct 22, 2008)

drgondog said:


> Erich - I don't presume he was lying about his impressions.
> 
> If the flight was recorded where are either the data or the tech reports after analyzing the data? If Willy M, or Lindner were aware of near to actual Mach 1 why didn't they report it it? Why would Messerschmidt keep this confidential - his greatest achievement?
> 
> ...



One big difference: The P-51 only has trim tabs, and if indeed the a/c reached the transonic region then they wouldn't work and the a/c would just continue to dive without the pilot being able to do anything about it, unlike the all moving tail plane on the Me-262 which would work! Mutke was able to recover from his dive only because of the all moving tail plane.



> No way any of those Mustangs were doing .85 mach with a combat config - the instruments said it and the damage implied it - but it didn't happen. I buy that the late model Spit exceeded .85 because of the wing - but I don't know if I believe .9 either...
> 
> and then for the 262, with those stupid nacelles buried under the wing with all the implied inlet potential issues, a relatively fat wing, potential wing-body-nacelle interference in the transonic range and a pitch down phenomena that should have no relief until actual supersonic flight is achieved - leaves a lot of unknowns between .86 M and 1.0.



That is simply nonsense Bill, the Me-262's wing was *thinner* than the Spitfires (and swept), so how can you call that a fat wing when you attribute the Spitfire's dive speed to exactly its "thin" wings ?! You're contradicting yourself Bill.

As for the pitch down, again the all moving tail plane could effectively counter that (Which is a proven fact), hence it's use on both the M.52 and X-1. 

Furthermore in a steep dive the pitch down wouldn't have time to develop enough negative G's before the a/c went supersonic, hence why the 1999 study makes it clear that the Me-262 would only be able to break the sound barrier in a steep dive. In a shallow dive, like that simulated by MTT, the a/c will remain too long inside the transonic region and there will be enough time for the Mach tuck to develop enough negatie G's to break the a/c apart.



> Unless and until the actual data surfaces with cross correlation to corroborate the claim -



Like the 1999 study..


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## Soren (Oct 22, 2008)

Kool Kitty89 said:


> I think he misspoke here Bill, since Soren seems to be responding to the snaking issue again, while you were commenting on the pitch-down behavior at Mcrit. (something Soren hasn't disputed)



Yes I read through his post abit too quickly, I was referring to the snaking issue caused by the rudder on a few a/c, not the Mach tuck.


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## kool kitty89 (Oct 22, 2008)

Soren do (or did) you have access to the 1999 University of Munich study on the Me 262 and if so, how much have you read. Do you know how others here could get access to it?


Bill, I agree that actuall access to the report would be necessary to be sure of what their conclusions were specifically. From what Delcyros has posted on it I tend to believe that it shows the distinct possibility of the Me 262 exceeding Mach 1 under the right conditions, but the only actual peice of the report i've seen is the speed vs altitude graph for the dives on pg.1.


For refrence, here's all the statements Delcyros posted on it:



delcyros said:


> There is scientific evidence, proposed by the technical university of Munich in an study which covers structural integrity of the Me-262 at different dive conditions. It shows that it is theoretically possible to exceed Mach 1.0 under certain conditions in a certain altitude with a certain load (You guess it- everything has to fit to make it through, which in turn makes it unprobable). Something which surprised me.
> 
> This study so far was never disprooved. The results of the study were challenged but not on scientific grounds.





delcyros said:


> Unfortunately not my friend. The study isn´t avaibable online. You might use the KOBV-Fernleihe to see the 1999 paper in question. The below page is from appendix II and shows how narrow to frame for reaching Mach 1.0 is at a pure vertical dive.





delcyros said:


> The idea behind the study is of more theoretical nature. Following Guido Mutke´s claims in the late 90´s, the TU Munich investigated the possibility.
> The initial dive condition -as far as I understood- was estimated to be very steep, >60 deg. At this condition, the nose down pitch at Mach >.86 would stabilize the -262 at a near or full vertical dive (90 deg) while the negative g-forces generated by the nose down pitch at a lower dive angles would be to excessive and lead to desintegration of the airframe. The steeper the initial dive angle, the higher the probability to stabilize in the vertical after loss of elevator authority due to nose down pitch. Or in other words: If the nose down pitch is small (requiring high dive angles), the airframe may survive. If thenose down pitch is to strong, the negative g-forces would become excessive (finally overmatching 90 deg). Elevator controll is blanked in this speed region but may or may not be restored once the speed of sound is exceeded, according.
> 
> Drag is still a considerable problem. Only once full power is applied (at this altitude the generated thrust is more like 500-600 Kp for each turbine @ 100% but weight of the airframe adds another 5-6tons thrust) and vertical dive established the study showed that Mach 1.0 may be approached _temporarely_ at a specific altitude. Once SoS is approached at this altitude, probability is high that a compressor stall cannot be avoided, zeroing out the engines. The technology was not there to prevent this.
> ...





In the case of the engines flaming out, the weight alone may have been enough to push it through. At 5-6,000 kg and the engines producing ~1,200 kp (kgf) total the engines would only be providing ~16-18% of the thrust, prior to the flamout.


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## kool kitty89 (Oct 22, 2008)

Soren said:


> One big difference: The P-51 only has trim tabs, and if indeed the a/c reached the transonic region then they wouldn't work and the a/c would just continue to dive without the pilot being able to do anything about it, unlike the all moving tail plane on the Me-262 which would work! Mutke was able to recover from his dive only because of the all moving tail plane.
> 
> *It would depend on how elevator control was lost at/near Mcrit. If it was excessive stick forces the trim tab would help. If the tail was emersed in turbulence from the wing, even an all-moving tailplane wouldn't help. -and the stick would not be frozen- If the wing-body design was such that the stabilizer was not blanked, the stabilzer's mach limit would be the limiting factor, but even then I think trim may still work depending on the characteristics of the shock/turbulence developed at the stabilizer.*
> 
> ...



In addition to the longer time spent in the damaging transsonic and -G inducing region in a shallow dive, accorfing to delcyros, the report stated that the pitch-down stabilized at a vertical dive atitude. So there would be no -G issues with a true vertical dive.

An interesting note to allied tests is that all seem to state that "no vertical dives were attempted." and that no attempt at exceeding the mach limit was made. (though given some of the statements in the Wright field Me 262 handbook, it would seem that vertical dives had been experienced in flights, though not specifically tested, particularly comments on recovering from dives exceeding Mcrit, though such conditions were not to be attempted)


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## kool kitty89 (Oct 22, 2008)

Bill (or anyone else knoledeable on this), for a swept wing aircraft (ie the F-86) the airfoil sections listed would not be taking sweep into account correct? 

Would there be any excepions to this? (and I know delta wings wouldn't apply, as there is no sweep affecting the airfoil, its simply a planform with a highly swept LE, likewise with most of the wings on modern fighters)


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## Soren (Oct 22, 2008)

KK,

The Me-262's horizontal stabilizer isn't emersed in turbulent flow, that's the reason it is placed so high, to keep that from happening. The thing that is causing the elevator trim tabs not to work is the shockwave forming near the rear of the horizontal stabilizer, causing turbulent flow over the control surfaces, the elevator trim tabs, rendering them ineffective. That is why the all moving tail plane works and the elevator trim tabs don't. 

The Me-262's stick never froze or became stiff, the control forces remained light throughout the speed range.



> Actually the all flying tail will only help if the wing-body design ensures that the entire tailplane isn't blanked by wing turbulence. And I believe the M.52 was to use a true all-flying tail, rather than a trimmable tailplane with elevator.



True, again the reason for mounting the tail plane high. The reason for the all moving tail plane being used as the main control surface for pitch was to improve maneuverability in transonic supersonic flight.


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## drgondog (Oct 22, 2008)

kool kitty89 said:


> Bill (or anyone else knoledeable on this), for a swept wing aircraft (ie the F-86) the airfoil sections listed would not be taking sweep into account correct?
> 
> Would there be any excepions to this? (and I know delta wings wouldn't apply, as there is no sweep affecting the airfoil, its simply a planform with a highly swept LE, likewise with most of the wings on modern fighters)



KK - the effect of sweep angle at the .25 Chord point is simply and effectively redeuce the freestream flow vector to a.) a chordwise component of the airflow over the chord, and b.) a spanwise component.

This has the effect of reducing the actual velocity chordwise - thereby enabling higher velocities before experiencing transonic flow over the airfoil. The 'bad' effect is the spanwise flow component. Same effect for Delta wing.

You aren't "wrong" by describing the effect of sweepback as reducing the t/c ratio, except that mathmatically speaking you need to reduce the freestream velocity to Vcos(sweepback angle at 1/4 chord) to get the right flow distribution over the 'real airfoil'

The latter is why vortex generators and wing fences are useful on highly swept wings, to help 'realign the spanwise flow' component.

The two primary advantages of a Delta wing over straight wing and swept wing for supersonic aircraft are 1.) a smaller shift in aerodynamic center from pre-transonic to supersonic. (i.e ~.35 to .50 versus .25 -.50) which is very significant for stability and control purposes. 

For all intents with respect to S&C, the Me 262 behaved like a straight wing in that respect. IMO this is the primary issue for the Nose down pitch problem
described for all the dive tests.


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## drgondog (Oct 22, 2008)

Soren said:


> One big difference: The P-51 only has trim tabs, and if indeed the a/c reached the transonic region then they wouldn't work and the a/c would just continue to dive without the pilot being able to do anything about it, unlike the all moving tail plane on the Me-262 which would work! Mutke was able to recover from his dive only because of the all moving tail plane.
> 
> *The 51 reached transonic in a dive, the elevator (and tabs) were not eliminated from acting and the 51 was able to pull out without the nose tuck issue. The max recorded and verified dive for a Mustang was .84/.85M for both the Mustang IV at RAE and the P-51D at Wright Pat.. with a fatter wing than both the Spit and the 262.
> 
> ...



Everybody talks about the Report but nobody is providing quotes from the combined aero and structures analysis to cite the supporting details - explaining how the 262 survived the experience from .86 through 1.0. 

Nobody seems to provide the trim requirements necessary to retard a serious negative G condition from the continued nose down tuck from 20 degrees to vertical in that speed range. Nobody speaks to the elevator loads above design limit load and points to an airframe that can survive the forces on either the tail or the wings.

Why not?


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## drgondog (Oct 22, 2008)

Soren said:


> KK,
> 
> The Me-262's horizontal stabilizer isn't emersed in turbulent flow, that's the reason it is placed so high, to keep that from happening. The thing that is causing the elevator trim tabs not to work is the shockwave forming near the rear of the horizontal stabilizer, causing turbulent flow over the control surfaces, the elevator trim tabs, rendering them ineffective. That is why the all moving tail plane works and the elevator trim tabs don't.
> 
> ...



True, but 'high' is relative.. out of the wake turbulence of the wing body is appropriate in more cases than a T tail


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## Erich (Oct 22, 2008)

well gents it is awful tough to prove anything I suppose, Messer was not interested in Guido's max out the jet flight he was involved head over heels with last ditch LW test trials of unknown swept back winged A/C for 1946 and beyond. Some day possibly we will get a full on report, we can gather all the factoids with graphs and what we know about the sped of sound but we also know for full on reasons that many LW docs during 1945 are lost to the wind, maybe just that special day will come when something buried is back from the lost and found and will tell you some of the LW JG materials were buried as such at their A/F's
~ in the report and it it is singed in my brain is that the rivets were popping the wings were buckling under the speed of the descent


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## DerAdlerIstGelandet (Oct 22, 2008)

Soren said:


> Only ? Adler the gun cover panel on the Me-262 was large and if torn away would create a very large gap in the nose and as-well as a large blunt area directly facing the airstream.
> 
> 
> 
> ...



Soren, more than likely it would not tear the aircraft apart. The pilot would have to lower the airspeed but he could fly the plane home and land. But what do I know? I am only trained and qualified to work on structures...

*All you are doing speculating and making up your own facts and truth. 

That is okay though, the forum is used to it after all these years.*


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## drgondog (Oct 22, 2008)

Soren said:


> Lets say the left gun cover comes off at Mach 0.86, that'd be pretty serious Bill. If wind is allowed inside a gap it will eventually, with increases in speed, increase the gap and lift the entire panel off.



Soren - ???? this 'red herring' was trotted out by you as a continuation of the poor quality issue you posed regarding 262. Everybody agrees that a panel coming off at .86 is potentially serious. Now what?

BTW - with reference to yaw issues. I found references by LW test pilot Fey, RAF pilot Morrison, and USAAF Test report that the CONSISTENT yaw issue occurred at aft Cg - dominantly with a full aft fuel tank.. in other words Every 262 with that condition at speeds staring at 350mph + and particularly noticable at 400. All on the Xeno website you posted earlier.


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## Soren (Oct 22, 2008)

> Wrong on "the shockwave at the trailing edge of the horizontal stabilizer"
> 
> A shockwave at the trailing edge only occurs when the ac is 100% supersonic in which case there would also be a shockwave at the leading edge.



You're right, I meant to say the leading edge as I've done in all the posts up to that one, I spun things around, that's what happens when you forget your morning coffee I guess..


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## Soren (Oct 22, 2008)

DerAdlerIstGelandet said:


> Soren, more than likely it would not tear the aircraft apart. The pilot would have to lower the airspeed but he could fly the plane home and land. But what do I know? I am only trained and qualified to work on structures...
> 
> *All you are doing speculating and making up your own facts and truth.
> 
> That is okay though, the forum is used to it after all these years.*



Great, a mod openly patronizing a member


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## Soren (Oct 22, 2008)

drgondog said:


> BTW - with reference to yaw issues. I found references by LW test pilot Fey, RAF pilot Morrison, and USAAF Test report that the CONSISTENT yaw issue occurred at aft Cg - dominantly with a full aft fuel tank.. in other words Every 262 with that condition at speeds staring at 350mph + and particularly noticable at 400. All on the Xeno website you posted earlier.



I'd like to see these references plz. According to Fey only 1/3 of the a/c he flight tested for service approval exhibited any yaw issues, so what you're saying doesn't make any sense.


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## kool kitty89 (Oct 22, 2008)

Soren I never claimed that the the wing-body design of the Me 262 was bad, I just stated that a proper configuration would be needed to keep the stibilizer from being blanked.

And I was talking about stick forces at/above the Me 262's Mcrit. If control was lost because the stick went stiff (for pitch, not roll), that was a GOOD sign in terms of the design, as it would mean that the elevator would still work if sufficient force was applied. (either with trim tab adjustment or if boosted controls had been added, as with the transsonic a/c I mentioned -particularly the F-86, and in the case of the P-38 which could recover from terminal dives using the trim tab)



Bill, would the shock wave at the stabilizer its self (when the critical mach number of the tailplane had been exceeded) result in stiffening controls, or "loose" ones. (the latter implying the elevator was "blanked")


Also, you didn't answer my questions about swept wings, I was asking what the data for the (root and tip) airfoil sections refers to. Are the figures for the wing measured in "straight" configuration, or are they taking the sweep into account. (the comment about Delta wings was that this would not be an issue in their case)

I had thought it was the former case (of the unswept section) but The Incomplete Guide to Airfoil Usage gives the airfoil for the Sabre as 9.5% root, and 8.5% at the tip. But this page North American XP-86 Sabre says that an 11% root and 10% tip were used. (which would apear that latter may be taking sweep into account)


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## Soren (Oct 22, 2008)

> Lindner and others are very explicit regarding the enormous stick forces required (50kg at .86) as the 262 progressed from .82 Mach. He specifically notes his struggle with both hands on stick trying to prevent the nose down tuck until he was able to free one hand to retard the throttles - and survive.



That I haven't heard before Bill, and it puzzles me abit as Fey makes it clear that the control forces are light at all speeds. Also I've never heard of heavy stick forces in the Me-262 before, could you show me the report by Lindner ?


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## kool kitty89 (Oct 22, 2008)

Then how was elevator control lost at .84+ mach Soren?

Good control forces up to the problematic speed range would be conceivable, but at critical mach I don't think you'd expect to have light controls. (inless the tail was emersed in turbulence like the P-47 aparently was at critical mach with the elevator being somewhat slack, but useless)


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## Soren (Oct 22, 2008)

> You are a self proclaimed expert at ballistics are you not?



Test me Bill, I think I know pretty much all their is to know about the subject.



> The physics works perfectly for bullets travelling faster than sound.



Pretty true, although there are variances.


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## delcyros (Oct 22, 2008)

A lot of discussion here.

I would like to quote two sentences from the spiegel magazine, which interviewed Ing. Jan Horn and Ludwig Bölkow from Messerschmidt, both claimed:

_ Ludwig Bölkow:"Wir flogen örtlichen Überschall", 
Jan Horn: " Nach meiner Kenntnis sind etwa vier bis sechs Schallmauerd
urchbrüche" gelungen. _

Note that no further, reinforcing data is presented. Both claims were raised in relation with Mutkes claim. It is likely that most of J. Horn claims refer to fatal dives which eventaully succeeded in breaking the speed of sound but failed coming back, e.g. returning to safe flight condition.

It should be quite interesting that Mano Ziegler also raised a claim for Heini Dittmar to have broken the sound barrier while making a full power dive in a Me-163B. Ziegler claims that on July 6, 1944, Heini Dittmar flying a pre-production comet Me 163BV18 VA + SP was measured travelling at a speed of 1,130 km/h measured with ground instruments, bangs heard clearly on the ground (Würzburg track).

I don´t have the technical background knowledge necessary to get involved in the discussion and so far I can only give a personal opinion to the topic:
With the present set of aviable records and despite Prof. Otto Wagners 1999 paper which approved a possibility (which by then was something new), Mutke´s claim cannot pass critical examination in a way to positively verify the event from a historical perspective, let alone a technical investigation.


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## Soren (Oct 22, 2008)

kool kitty89 said:


> Then how was elevator control lost at .84+ mach Soren?



Mach 0.86, because of turbulent airflow over the control surfaces of the tailplane cause by the shockwave forming at the LE, like I said very early on in this discussion to Bill: 

_"I don't believe the entire 'horizontal stabilizer' was immersed in turbulent flow Bill, the elevators might have been because of the shockwave produced at the LE of the stabilizer, but not the entire stabilizer. So like Muthke one could trim the a/c out of the dive by utilizing the fully movable horizontal stabilizer, which is what he did."_


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## HoHun (Oct 22, 2008)

Hi Delcyros,

>I would like to quote two sentences from the spiegel magazine, which interviewed Ing. Jan Horn and Ludwig Bölkow from Messerschmidt, both claimed:

Do you happen to know the exact issue the article was in? I think it was not a real interview feature, but just some quotes in the text of a journalist's article. (At least, if it's the same article I've read a couple of years back.)

Thanks in advance!

Henning (HoHun)


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## drgondog (Oct 22, 2008)

Soren said:


> Test me Bill, I think I know pretty much all their is to know about the subject.
> 
> *Then why did you miss that little point about supersonic shock waves?*
> 
> Pretty true, although there are variances.



*Your example might be? It is exactly true - not pretty true.*


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## Soren (Oct 22, 2008)

> Then why did you miss that little point about supersonic shock waves?



I didn't, read my post. Infact read my last post.



drgondog said:


> *Your example might be? It is exactly true - not pretty true.*



Normal spitzer at 2,200 fps, large shockwave at the tip AND near the back.

Same with a/c, shockwaves form both at the LE AND the TE in supersonic flight.

However a variance occurs when changes in shape occur along the object, you didn't note that.


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## drgondog (Oct 22, 2008)

Soren said:


> Mach 0.86, because of turbulent airflow over the control surfaces of the tailplane cause by the shockwave forming at the LE, like I said very early on in this discussion to Bill:
> 
> _"I don't believe the entire 'horizontal stabilizer' was immersed in turbulent flow Bill, the elevators might have been because of the shockwave produced at the LE of the stabilizer, but not the entire stabilizer. So like Muthke one could trim the a/c out of the dive by utilizing the fully movable horizontal stabilizer, which is what he did."_



LOL - go back to my earlier reply to your 'trailing edge shock wave boo boo' reply where you can't doctor your quote - you said TRAILING EDGE Soren.

Theoretically, if the sweep angle was less and the airfoil thickness greater on the horizontal stabilizer - supersonic flow and SUBSEQUENT shock wave at the leading edge could occur. What was the 262 tail geometry and airfoil?

But a.) the tail has to go supersonic at or below .86 for the shockwave to exist at .86, and b.) because the slab tail was there it would be very effective even at supersonic speeds.

So, to emphasize some points. 
1. I don't believe the nose over an the attendant control stiffness was cause by the the elevator being blanked nor do I believe the elevator went supersonic well below Mach 1.
2. I do believe the pitch down was caused by the transonic shock wave forming in the .82-.86 range, thereby moving the ac back from .25 to ~.5 chord point. I don't know if the ac center had moved all the way to .5 chord at .86.
3. As a result of the aft movement of ac, the CMac changed from close to neutral to a decided and progressive nose down pitch about the lateral axis of the airplane, requiring increasing 'Up' elevator to compensate for nose down pitch forces.
4. I believe further that the increasing stick force required to offset the increasing CMac due to increased airspeed was a direct result of the required elevator forces on the airframe to try to move the nose back up. This is my biggest area of doubt regarding 262 capability to reach Mach 1 with all the parts wired together.
5. The question remaining about all this is twofold. 

One - did Mutke not have enough strength to continue retarding the nose down pitch forces and the 262 continued to a stable point (i.e. vertical) despite all he could do? Or did Mutke intentionally go vertical and immediately pull the throttles when he had a free hand, then as the 262 slowed down to below .82, was he then able to avoid another 'pitch down moment' in the transition....

and BTW as the 262 transitioned from >.86 M to the pre shock wave migration velocity then his huge aft stick force to hold attitude suddenly goes away and the 262 would quickly require a push forward to prevent a too rapid pull up.

If he actually did achieve Mach 1 he is the luckiest SOB that ever flew an airplane to survive.

I go with the former scenario..and the latter 'luck' condition - and still do not believe it happened.


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## Soren (Oct 22, 2008)

> LOL - go back to my earlier reply to your 'trailing edge shock wave boo boo' reply where you can't doctor your quote - you said TRAILING EDGE Soren.



Doctor ???! I took it straight from the post man! 10-14-2008, 11:32 PM, Post #84.

I accidently confused it around in the post where I said it was at the trailing edge in the transonic region when I should've written leading edge, I already mentioned that one page back in reply to your response to it, go back and read it yourself.


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## drgondog (Oct 22, 2008)

Soren said:


> I didn't, read my post. Infact read my last post.
> 
> *The last post cleverly corrected the original post 198 - see below*
> 
> ...



This is your direct quote from post 198 to KK

*KK,

The Me-262's horizontal stabilizer isn't emersed in turbulent flow, that's the reason it is placed so high, to keep that from happening. The thing that is causing the elevator trim tabs not to work is the shockwave forming near the rear of the horizontal stabilizer, causing turbulent flow over the control surfaces, the elevator trim tabs, rendering them ineffective. That is why the all moving tail plane works and the elevator trim tabs don't. 

The Me-262's stick never froze or became stiff, the control forces remained light throughout the speed range.

*


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## Soren (Oct 22, 2008)

Bill, 

Before you turn nasty childish once more read post #205.

You that's the problem with you Bill, you make one mistake, be it a typo or accidental swap around, you emmidiately jump in calling one a liar. You don't understand simple mistakes. And furthermore, and this is what usually makes debating with you a very unfriendly and childish affair, you have a nasty and a bit disturbing habbit of bringing in previous and completely unrelated debates to strenghten your own argument by trying to either ridicule your opposition or induce doubt as to his credibility.

You just don't know what an honest mistake is.


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## Soren (Oct 22, 2008)

Btw, I am still waiting for the references you claim to possess Bill.


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## Waynos (Oct 22, 2008)

Sorry I think I'm getting confused. Fair enough, anyone can make a mistake and say or type the wrong word, but, as quoted above, didn't you then go on to describe exactly which bit of the tail you meant (control surface and trim tabs, which are at the rear)? How can you do that by mistake?


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## Soren (Oct 22, 2008)

Waynos,

There's nothing untrue about the shockwave rendering the rear control surfaces ineffective (The very reason for the all moving tail plane), it's the placement of the shockwave which is at the LE in the transonic region (Like I've said earlier), and NOT the trailing edge as I mistakenly wrote.

But if I wasn't aware of this (As Bill oddly seems to suggest) then why did I make it clear earlier, seriously ?  

I made a swap around, a mistake, that's it.


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## kool kitty89 (Oct 22, 2008)

Sore, what I was asking was what the charaterisics of the stick forces were at critical mach. As I understand it, elevator control loss comes in 2 possible forms 1: excessve control forces, 2: being blanked by turbulence with controls still movable.

Which is the case for the Me 262? (if it's the former, boosted controls would allow the elevator to work as it did in the F-86 -granted the F-86's tailplane had a higher Mach number as well) 

And you never answered my question from post #195.



That's very interesting on the Me 163 Delcyros. I would think that the thick root section (14% -not sure about sweep-) would be too thick, not to mention the wooden wing construction. (not to mention the trim problems of tailless aircraft in the transsonic regionand possible issues with the LE slots at such speeds) Besides the much breater thrust available at these speeds, I think the Me 163 would be less likely sucessfully perfrom this feat than the Me 262.



Bill, Data for the Me 262's tailplane airfoil would be interesting, but I immagine that's going to be difficult to find. (also not there was no sweepback to the tailplane, it just had LE taper, there was a ~20 degree swept-back version used on the HG I/II though)

*And again:* Bill, could you clarify my question on swept wing airfoils. see post #208


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## drgondog (Oct 22, 2008)

Soren said:


> Btw, I am still waiting for the references you claim to possess Bill.



Re: snaking and dutch roll? Go back to your post which has the link to the Me 262 POH. There is the POH Handbook compiled by USAAF from the flight tests and German intelligence debriefings post war with persons such as Lindner and Fey - LW and Morrison - RAF

1. Then wander into Stormbird Rising 

Appendix C, page 197-198, and go to section 3. Flight Characteristics, par e. "The handling characteristics were poor at all speed above 350 mph. The airpland would not make a very good gun platform because of a tendency to hunt directionally in snaking at speeds above 400mph"

The above is from the series of tests performed on USAAF inventory numbers T-2-711 (wn111711) and T-2-4012 (no given wn) in February 1947 and reported in F-TR-1133-ND

2. Appendix B, RAF Interrogation Report of Gerd Lindner, and later verified by Karl Baur before the 1947 Flight Tests at Wright Pat.

page 194 
Aircraft Performance and Flying Qualities "12. Maximum altitude from ZLindner was 12,400 metres. Maximum speed ever attained with the Me 262 was 1004 Kmh at 4300 metres, the angle of flight being between 20 and 25 degrees"

Behavior in a High Mach number dive "35. Lindner stated that the Machmeter was not successful; He said the experiments with high speed were made with 70 altimeters mounted in the fuselage and photographed automatically every 1/2 second. These altimeters were connected to chordwise holes in each mainplane. The true airspeed indicator would be checked by flying between two tall chimneys. The interpolation, after a test flight, of all the altimeter readings, and those of the TAS indicator, enabled an accurate determination to be made of the mach number attained in the flight."

"38. Lindner stated that he climbed to 8000 metres and dived at an angle of 20-25 degrees where mach number 0.86 was reached. He reached 1000 kmh TAS (as read on the TAS indicator), giving he said a corrected mach number of 0.86. At Mach 0.83 the nose started to drop, and he had to pull the stick with a force of 15kg with both hands. As the Mach number increased, a violent buffeting set in, appearing to come from the canopy behind his head and producing a very high frequency banging noise. The aircraft became more nose heavy, and at mach 0.86 he was pulling with a force of 40-50 kg.

"40. On the strength of these tests the service pilots were instructed to not exceed a 'true airspeed indicator" reading of 950 pmh and were advised to set the trimmer so that a slight push was required to initate the dive. They were also told to not use the trimmer for recovery. Several fatal accidents have occurred in the Luftwaffe which Lindner attributed to pilots exceeding this speed limit, and being unable to pull out using both hands - the forces being so great that they could not get one hand from the stick to the trimmer."

"46. Elevators. The first few Me 262s were fitted with fabric covered elevators. At speeds between 850-920 TAS (indicator) at about 1000/2000 meters, ballooning of the fabric occurred. This could result in the aircraft showing a tendency to nose further in the dive. Sometimes the fabric would burst; this had occurred five tmes and in each case the aircraft had landed safely; recovery from the dive being effected by means of the adjustable tailplane. The fabric was replaced by metal."

The last point by Lindner should put a few of the proposed transonic questions to rest.

1.The ballooning effect should cause probable flow separation over the elevators, reducing the overall effectiveness of the elevator - but demonstrating the slab tail was still effective at very hign speeds near transonic.

2. The nose down effect was a direct consequence, pre-shockwave, was a consequence of losing some horizontal stabilizer effectiveness - not the next issue of transonic flow causing a huge increase of CMac.

Any other references other than the link you provided plus the above.

Now - where are YOUR references?


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## Soren (Oct 22, 2008)

It's nr.2 KK, the elevator trim tabs are still movable but emersed in turbulence thus ineffective. But like I've been saying from the beginning not the whole horizontal stabilizer is emersed in turbulent airflow, only the rearest part where the control surfaces are located, and again because of the shockwave forming at the LE of the stabilizer fin. So trimming the taiplane will work. Thus the only way to change pitch attitude in transonic flight is to trim the tail plane, like Mutke did. 

If it were option nr.1 you'd read it in the a/c manual as the control forces will increase gradually along the speed range, but no such thing is mentioned. What is said is that the controls remain light throughout the speed range, even at very high speed. As a matter of fact I've never heard or read about high stick forces in the Me-262, from all that I have read about the a/c the controls were light and well harmonized at all speeds.


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## drgondog (Oct 22, 2008)

kool kitty89 said:


> Sore, what I was asking was what the charaterisics of the stick forces were at critical mach. As I understand it, elevator control loss comes in 2 possible forms 1: excessve control forces, 2: being blanked by turbulence with controls still movable.
> 
> *You are correct*
> 
> ...



KK- the freestream only 'sees' the LE angle, but the normal and tangential velocities are reduced to the 1/4 chord. The 163 had a clear sweepback increase over the 262 and even with a higher (but not much higher) increase to t/c should delay transonic region to a higher freestream Mach number.


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## Soren (Oct 22, 2008)

Bill,

Here are MY sources:

Go here: http://www.zenoswarbirdvideos.com/Images/Me262/ME262PILOTDEBRIEF.pdf

Read under flying characteristics, from Me-262 test pilot Hans Fey:

_*"There is no flutter while diving. Fay conjectures the reason for this to be the high position of the horizontal stabilizer in relation to airflow around the wings.

Around one third of the airplanes tested by Fay had a slight tendency to skid during their first flights. This was easily eliminated by adjusting the trim tab on the rudder"*_

Now read this, the Allied POH for the Me-262 prepared by Allied test pilots:
http://www.zenoswarbirdvideos.com/Images/Me262/262PilotHandbook.pdf

Again under flying characteristics, surprise surprise, similar conclusions, great flying characteristics, no flutter in dives, utilizing the tail plane trim is too effective. Btw note the German air speed indicator lists TAS.

No where, I repeat no where do I see anything about poor handling! Infact I find quite the contrary, the handling of the a/c is praised by all who flew it!


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## kool kitty89 (Oct 22, 2008)

Bill, 14% compared to 11% thickness is a pretty big difference, not to mention the airfoil characreristics were different. (with max chamber of 18% chord located at 25% chord) I don't know what the thickness is with sweep taken into account though. 

I don't think I fully understan the properties of swept wing though. I know of the increase in chord, the (detrimental) spanwise flow, and the advantages in the supersonic. (keeping the wings behind the shock wave) And than in the transsonic region the sweep reduces wave drag by "sweeping" the shockwaves developing on the wing. Does the spanwise flow its self increase critical mach number? (I'm going to look for some articles on it)

Would the rather high degree of LE taper on the P-80 and Vampire contribute to higher critical Mach numbers?




Soren, the Wright Field manual makes similar comment about good stability and lack of elevator flutter at high speeds. (noted to be likely a result of the tail position)

Again referring to the Mcrit characteristics of the rudder, I may be mistaken, but I think the shockwave developed at the tailplane (when it's Mcrit is exceeded) could result in either of the 2 possible loss of control problems I mentioned. (loose stick-blanked elevator, or immovable due to exteme control forces) The "blanking" problem can also result from wing turbulence as previouslt mentioned, but that's not the issue here.


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## drgondog (Oct 22, 2008)

Soren said:


> It's nr.2 KK, the elevator trim tabs are still movable but emersed in turbulence thus ineffective. But like I've been saying from the beginning not the whole horizontal stabilizer is emersed in turbulent airflow, only the rearest part where the control surfaces are located, and again because of the shockwave forming at the LE of the stabilizer fin. So trimming the taiplane will work. Thus the only way to change pitch attitude in transonic flight is to trim the tail plane, like Mutke did.
> 
> *BS Alert. The elevator and trim tabs are not only movable but not immersed in turbulence - unless you have aspecific reference to the contrary. where is it? If the shock wave is at the LE, there is a shockwave at the TE. The flow in between is reasonably laminar and supersonic - the stupid tail in this condition has gone SUPERSONIC Soren. What else don't you understand about supersonic flow over an airfoil???? Freestream in front of tail is ALWAYS SUBsonic, Shockwave starts at leading edge. At Trailing edge the flow transforms from supersonic back to SUBsonic. Freestream airflow aft of the airfoil is also ALWAYS SUBsonic!!
> 
> ...



BS ALERT. You still beathe your own air and dismiss the top two test pilots at Messerscmidt - Lindner and Baur who directly contradict what you are saying. I just laboriously recapitulated the interview and the source. What sources do YOU have discussing 'light stick forces between .80 and .86 Mach?


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## drgondog (Oct 22, 2008)

Soren said:


> Bill,
> 
> Here are MY sources:
> 
> ...



You have a disturbing tendency to leap at sunshine and avoid the dark. 

If Lindners debriefing, verified by Baur is BS - PROVE IT! They forgot more than you will ever know and their testimony and verification directly contradict what you say..


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## kool kitty89 (Oct 22, 2008)

Ok, I think I understand the swept wing issue. (increased chord asside) Due to the sweep, the speed of the airflow over the wing is lower than it would be with a similar straight wing. It doesn't have anything to do with spanwise flow OVER the wing (and this doesn't even really occur at high speed and low AoA) but the airflow being spit with some flowing outward along the wing LE and the rest flowing over the wing. Thus the Mach number of the air flow experienced by the wing will be lower than that of the freestreem.

So a straight wing of 9% chord will have a lower critical mach number than a 35 degree swept wing of 11% chord of similar airfoil type. (despite the true chord length of both wings being the same)

Also, the Komet apears to have a LE sweep of ~26 degrees. (the P-80 has one of ~12-15 degrees, though at the root it apears to be greater than 20 degrees. The vampire looks like ~15-18 degrees) 
Additionally the Me 262's wing its self, while having a LE sweep of 18.5 degrees, only seems to have been swept back (outboard of the nacelles) ~11 degrees, to the change in actual thickness would be only ~2%. And this section is of 11% (at 40% chord) tapering to 9%.

Also the LE sweep of the tailplane is ~25 degrees and the fin's is ~45 degrees.



However, I still don't know if the airfoil data for swept wing a/c is from a "head on" (unswept) perspective or if it's a measure of the true swept wing. (if it's the former, the 11% chord refrence to the F-86 would be in error)


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## claidemore (Oct 23, 2008)

Fay never flew any of his test planes higher that 13000 feet, and did not push them to the limit of dive speed, only enough to pass acceptance tests. When he speaks of no flutter while diving, he is *not *talking about Mach .84 or .86, but of speeds in the 600mph or less range. His job was to make sure the plane could make minimum speeds for acceptance, not to test their max performance. 

And that report is a second hand summarization, written by an interrogator/interviewer, not by Fay himself. 

In no way can it be compared to an actual test report.


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## Soren (Oct 23, 2008)

drgondog said:


> You have a disturbing tendency to leap at sunshine and avoid the dark.
> 
> If Lindners debriefing, verified by Baur is BS - PROVE IT! They forgot more than you will ever know and their testimony and verification directly contradict what you say..



Give me a link to Lindners debriefing and Baur's verification Bill cause I can't find it.

No to reverse what you just said, are you saying that what LW test pilots Fritz Wendel Hans Fey as-well as the Allied test pilots are saying is BS ??


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## Waynos (Oct 23, 2008)

I have to concur with Claidmore, nothing in that interview with Fey ever mentions transonic speeds, only general acceptance trials. Indeed the words 'transonic' and mach do not even appear in the document (a quick ctrl F will demonstrate that). It even states that as long qas the plane could attain 510mph it was was passed as OK and that on several occasions Fey found himself parting company with parts of the plane, which all seems to support the opposite view.


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## Soren (Oct 23, 2008)

Waynos reread the report plz, you can read that every a/c had to pass 1,000 to 1,050 km/h dive speed tests, which is well within the transonic region at 6-8km.


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## drgondog (Oct 23, 2008)

Soren said:


> Give me a link to Lindners debriefing and Baur's verification Bill cause I can't find it.
> 
> No to reverse what you just said, are you saying that what LW test pilots Fritz Wendel Hans Fey as-well as the Allied test pilots are saying is BS ??
> 
> *No I am not and have not - see specifically my comments extracted from Wendel below.*



The "link" I provided for the above quotes are extracted verbatim from the book Stormbirds Rising by Hugh Morgan and published by Osprey in 1994. I believe I noted that before launching into the entire series of quotes.

The section in the POH handbook from the link YOU provided is found on page 7 Section 2 - Pilot Operating Instructions, para c. "Center of Gravity" and para d. Take Off Weights and Balances.

You apparently missed this section. In case you don't know what to look for I recommend you pay particular attention to the instructions to not put fuel in the rear tank and also the explanation of the behavior when the afte cg exceeds 30% MAC. You will find reference to both the yaw and stall issues when that restriction is ignored.

http://www.zenoswarbirdvideos.com/Im...otHandbook.pdf

If you will search diligently you will also see that I never claimed that the 262 had flutter problems. In fact the only reference I ever saw relating to harmonic issues at all was Lindners reporting of "severe buffeting and high frequency banging noise". I assumed from this description that he was experiencing the first real separation (and severe turbulence aft of cockpit) of flow from both the wings and fuselage - not flutter.

Flutter would have been transmitted to his stick and the description should be different.

Now - since we are quoting from Wendel, take a look at the report by Kapitan Fritz Wendel in your link

Flying the Messerschmitt Me-262

Go to page 4, sections 7 and 8 and take a glance at the warning for aft cg as well as rigging for further reference to yaw issues. I recognize that similar issues and warnings surrounded a Mustang when the aft fuse tank was loaded... but these instructions apply to EVERY Me 262 - not just a few with "QC/QA" issues and poor quality... as similar instructions applied to 51 drivers for normal operations in which the tank had to be filled

Are we about 'done' with snaking? 

We still have a question about the issue at high speed as it was seemingly encountered in the two tested after the war and brought to the US. Based on all the data, I suspect further that the problem experienced by the US test flights might have been related to the rigging issue discussed by Wendel.


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## drgondog (Oct 23, 2008)

kool kitty89 said:


> Ok, I think I understand the swept wing issue. (increased chord asside) Due to the sweep, the speed of the airflow over the wing is lower than it would be with a similar straight wing. It doesn't have anything to do with spanwise flow OVER the wing (and this doesn't even really occur at high speed and low AoA) but the airflow being spit with some flowing outward along the wing LE and the rest flowing over the wing. Thus the Mach number of the air flow experienced by the wing will be lower than that of the freestreem.
> 
> *That is the theory as well as the way it is applied. The airflow 'sees' the correct airfoil in the chordwise component - but that component is Vfreestream*COS(angle of 1/4 chord sweep) and lower than V freestream*
> 
> ...



It gets a little tricky here. First, the sweepback angle relative to airplane axes is in fact referenced to the LE. A 35degree sweep wing is 35 degrees from the perpendicular to the CL and 125 degrees from CL

For an untapered wing of very high AR (approximating 2-D) the airflow component is in fact Vfs*COS(Sweep LE) and the airfoil profile perpendicular to the LE is in fact the areodynamic profile for that flow.

Real world for a tapered wing is that for a close approximation of design to reality you assume the normal flow is perpendicular to the 1/2 chord.

Now it gets trickier going from aero design to the shop floor. Frequently the structural ribs hanging off the spar will be perpendicular to the main spar but they may also be designed parallel to fuselage. 

Obviously the rib for a 'parallel' design will be the 'true 'aerodynamic profile reconstructed at an angle from the spar. So the lines group gets involved to ensure the manufactured rib running parallel to the airframe which creates the airfoil surface of the skin, when cut perpendicular to the spar, results in an airfoil section which is what the areos specified.


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## claidemore (Oct 23, 2008)

Soren said:


> Waynos reread the report plz, you can read that every a/c had to pass 1,000 to 1,050 km/h dive speed tests, which is well within the transonic region at 6-8km.



You need to re-read the report Soren. Every a/c had to pass a *950kmh 30 degree dive test*. 

Fay said that speeds in the 1000 to 1050 range were 'spoken of' as the absolute maximum. He also said that if the dive speed only reached 900 kmh, the plane was passed anyways.


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## DerAdlerIstGelandet (Oct 23, 2008)

Soren said:


> Great, a mod openly patronizing a member



No, only pointing out the truth. The forum (not just mods) has known this for quite some time.


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## Juha (Oct 23, 2008)

Soren

Quote ” As a matter of fact I've never heard or read about high stick forces in the Me-262, from all that I have read about the a/c the controls were light and well harmonized at all speeds.”

Please look Hohun’s message #36 in this very thread, or better still the Flight Journal Winter 2000 which HoHun gives as the source. Same can be found from Brown’s Wings of the LW p. 66. Brown's own dives on the 262 up to a max Mach 0.84 fully confirmed all Lindner's observations.

From the latter “On the strength of these tests [flown by Lindner, Juha] , the LW pilots had been instructed not to exceed airspeed of 960 km/h below 8 000m, more than 900 km/h being considered inadvisable above that altitude…the trimmer should not be used as an aid for recover”

Juha


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## kool kitty89 (Oct 23, 2008)

Thanks *Juha*, *HoHun*'s post makes the characteristics very clear.


HoHun said:


> Regarding the resulting control forces, here is an interesting comment by Eric Brown (from Flight Journal Special Winter 2000):
> 
> "In the dives from 30,000 ft, the nose started to drop at Mach 0.83 and a 30-pounds pull was required to maintain the 25-degree dive angle. As the Mach number increased a violent buffeting set in, and the aircraft became progressively nose-heavy, so a pull force of about 100 pounds was necessary at Mach 0.86 to keep the dive angle constant."
> 
> ...



It seems that the controls aren't getting "stiff" as much as the aircraft was getting nose heavy (due to a movement in center of lift at critical mach). It would also seem that at these speeds the tailplane's critical Mach number hasn't yet been exceeded. So it may have been possible that trimming the tailplane to counter this (restoring proper trim) would have left elevator authority intact as well. (at least until the tailplane reached critical Mach)

That would make sense too, as the ailerons and rudder were still effective at these speeds. 



*Bill*, when the tailplane's critical Mach number is exceeded, will the resulting shock wave (and turbulence) definitely result in loss of elevator control? (regardless of stick forces -or control boost- applied) 
Or are there other factors in the tailplane's characteristics that could effect this?

My understanding is that when Mcrit is exceeded a shockwave develops (first on the upper surface, later on the lower) and the control would be lost once the shock was significant enough to make the airflow separate before reaching the control surface(s).

Also, will the elevator become functional again once the entire tailplane has gone supersonic? (assuming sufficient control forces -ie boosted elevator controls)


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## Juha (Oct 24, 2008)

KK
As Soren rather childishly asked Bill to provide a link to the book Bill used as his source I gave the HoHun’s message as an independent proof to Bill’s message, because HoHun’s message is a short version of Bill’s rather extensive message #225. And so it has to be, because Brown’s comment is a quote from Lindner’s report. I only added that Brown’s own dives on the 262 up to a max Mach 0.84 fully confirmed all Lindner's observations. And same time added another source, Brown's book, from where to check Lindner's observations.

Juha


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## Soren (Oct 24, 2008)

Juha, how is asking for sources childish when I am asked for the same as-well ? Bill asked for sources, I provided the Me-262 POH.


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## pbfoot (Oct 24, 2008)

Is there really such a thing as a POH for LW Aircraft, not according to my sources who say the data on the aircraft was "beaten into them in class" and says all the operating notes or POH was post war creations I have no reason to doubt my sources.


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## Soren (Oct 24, 2008)

I think I'm just gonna repeat what I'm trying to point out here:

_I say the Me-262 quite clearly broke the sound barrier because as Mutke explains the heavy vibrations and uncontrollable pitch down his a/c exhibited while in the transonic region suddenly seized and a smooth ride followed while still in the dive, after which he shut his engines and started to trim the tail plane to recover from the dive (The all moving tailplane is what allowed him to recover from the dive as shockwaves rendered the elevators ineffective), shortly after the vibrations started again. This to me is a clear sign that he went supersonic. And studies done in Germany in 1999 prove that it was possible for the Me-262 to go supersonic, but it was risky and damage to the a/c was almost assured, and depending on the quality of the workmanship of the airframe it could come apart in the attempt as-well. 

Further proof that the Me-262 either went supersonic or came extremely close to it is the British claims that the Spitfire, a propeller driven a/c, reached Mach 0.9 in dives. The claim is substantiated by the fact that the speeds were recorded to be viewed afterwards. The Spitfire featured no wing sweep and being a propeller driven a/c it had absolutely no thrust at such high speeds, so to explain why the a/c was capable of such a speed it is claimed that it is the unusually thin airfoil which gave the a/c its high Mach number. 

Keeping the above in mind it should be mentioned that the Me-262 not only featured a thinner wing than the Spitfire but also wing sweep, and even more crucial is the fact that the Me-262 is a Jet and thus has available a lot of thrust at high speeds. Furthermore the Me-262 is a much cleaner a/c than the Spitfire.

In level flight the average Me-262 achieved a top speed of Mach 0.77 to 0.79 at a height of 6km (The British established the top level speed to be 900 km/h in several recorded flights).

So there is absolutely no doubt in my mind that the Me-262, along with the Me-163 F-86 Sabre, broke the sound barrier before Chuck Yeager in his X-1 craft._

In short, IF the Spitfire could reach Mach .9 in a dive, a speed at which the prop acts as nothing but a speed brake, then you can pretty sure that the Me-262 could go even faster in a dive as not only is it a jet but it's cleaner, got a thinner wing and features some wing sweep.

So the only WW2 a/c which could've gone supersonic or come closest to it is the Me-262, Me-163 or Go-229 prototype.


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## Soren (Oct 24, 2008)

pbfoot said:


> Is there really such a thing as a POH for LW Aircraft, not according to my sources who say the data on the aircraft was "beaten into them in class" and says all the operating notes or POH was post war creations I have no reason to doubt my sources.



What are your sources exactly ? The reason I'm asking is that I have both the LW Ta-152H Me-262 POH, the Ta-152's was printed in January 1945.


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## Juha (Oct 24, 2008)

Soren
in his message #225 Bill gave his source, Stormbird Rising, with page number ,but in Your message #234 you still asked 
Quote:“Give me a link to Lindners debriefing and Baur's verification Bill cause I can't find it.”

That’s the reason to my comment.

On early jets vs late propeller planes
And how You explain that in RAE’s tests its High Speed Flight Section found out that Spitfire PR XI could dive faster than for ex Meteor or Vampire? The critical point isn’t trust, look the table on Mach .89 dive of PR XI, the dive angle was at its max a bit over 45 deg. The limiting factor was the ability of pilot to pull the stick, at 0.89 the pull needed on PR XI was the same 110lb than Lidner tells was needed on 262 at 0.86. Brown tells that for him the max on PR XI was .86 because of his small statue, he didn’t have as much muscle power as Tobin? or Martindale and maybe he left a bit more margin than those other two when he began his pull out.

Juha


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## Soren (Oct 24, 2008)

Juha,

A Meteor Vampire isn't a Me-262, both featur thicker wings, lower thrust, minimal to no sweep.


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## Juha (Oct 24, 2008)

Soren
otherwise true but Meteor III had two Rolls-Royce Derwent I with 900 kgp trust each, so so much to your “even more crucial is the fact that the Me-262 is a Jet and thus has available a lot of thrust at high speeds.”

Juha


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## drgondog (Oct 24, 2008)

kool kitty89 said:


> Thanks *Juha*, *HoHun*'s post makes the characteristics very clear.
> 
> *Bill*, when the tailplane's critical Mach number is exceeded, will the resulting shock wave (and turbulence) definitely result in loss of elevator control? (regardless of stick forces -or control boost- applied)
> Or are there other factors in the tailplane's characteristics that could effect this?
> ...



Yes.

I feel (no proof) that the issue at .82-.86 M was that the tailplane did not have enough boost to deflect down with normal pilot strength to overcome the loads imposed by the Down pitching moment in the transonic initiation - and further suspect that existing mechanical advantage of the tailplane was designed with the structural integrity in mind. 

Hence the 'Do not Use Trim' directive - except in absolute emergencies.

The additional trim at those speeds would probably be the factor that caused several 262s to crash in dives although I have not seen any reports of a tail separating to validate that speculation - so, it is pure speculation on my part


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## drgondog (Oct 24, 2008)

Soren said:


> I think I'm just gonna repeat what I'm trying to point out here:
> 
> _I say the Me-262 quite clearly broke the sound barrier because as Mutke explains the heavy vibrations and uncontrollable pitch down his a/c exhibited while in the transonic region suddenly seized and a smooth ride followed while still in the dive, after which he shut his engines and started to trim the tail plane to recover from the dive (The all moving tailplane is what allowed him to recover from the dive as shockwaves rendered the elevators ineffective), shortly after the vibrations started again. This to me is a clear sign that he went supersonic. And studies done in Germany in 1999 prove that it was possible for the Me-262 to go supersonic, but it was risky and damage to the a/c was almost assured, and depending on the quality of the workmanship of the airframe it could come apart in the attempt as-well.
> 
> ...



The point is - there is a remote possibility that Mutke did exceed the speed of sound in an airplane that Willy M directed to be flown below .86 M. 

There is a remote possibility that the study you referenced did prove that the stability and control design features of the Me 262 were sufficient to proceed into a vertical dive and at that point remove the pitch down moment before it became a cloud of aluminum particles. 

There is a remote possibility that the study proved that the tail structure was in fact adequate to enable the forces required to pull the a/c out of a dive from 1.0 Mach or survive the continued pitch down forces after .86 M. 

There is a higher possibility that the study proved that the Me 262 could reach a terminal velocity > 1.M after the engine flamed out or prove that the inlet geometry was adequate to prevent shock stall of the Jumo engine.

That would be an analytical approach to support a 'possibility'

Nothing factual supports the reality.


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## Soren (Oct 24, 2008)

> Babble.. speculation, supposition, no facts



Babble my ass Bill, Mutke's account is as it is, it isn't babble, so if you don't believe the details of it then why not just be open and call the man a liar ?? And the study done in Germany DID conclude that the Me-262 was capable of breaking the sound barrier in a steep dive, so again not babble, just facts, just how you like it right ?


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## Soren (Oct 24, 2008)

> Soren, the uninformed and irrational frequently exist in a state of absolute confidence in their personal point of view. Your rationale and fact base are adequate to support your belief system but fail to meet the test of fact based science. However, your zeal and enthusiasm in the pursuit of the ludicrous is to be commended. You are a triumph of the uncluttered mind.



Why is it you have to be an ass toward others Bill? Have I called you names or anything else in this entire debate ?? NO! So why is it you insist on being childish and calling others names ? You love to do this things when you get overconfident in yourself. Stick to the subject, refrain from childish name calling, base your own conclusions on facts instead of requiring them from others. 

Babble, ha!


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## drgondog (Oct 24, 2008)

Soren said:


> Babble my ass Bill, Mutke's account is as it is, it isn't babble, so if you don't believe it then why not just be open and call the man a liar ?? And the study done in Germany DID conclude that the Me-262 was capable of breaking the sound barrier in a steep dive, so again not babble, just facts, just how you like it right ?



I didn't say Mutke's account was 'babble' - I said Your entire dissertation was babble. I have never said that I disbelieve Mutke's impressions - I just don't believe he exceeded Mach 1.

Produce the report - your say so and your interpretation of engineering concepts are demonstably below par and frequently absent facts. 

Remember 'Suction=Drag' was your interpretation of Lednicers report? Do you recall saying the '262 control forces are light at all speeds"? Do you recall saying that the shock wave on the elevator started at the trailing edge? 

Do you recall your interpretation of the USAAF recount of 'snaking and hunt in the horizontal' as trash and associated that to 'only one or two' based on quality issues? 

As to not insulting me - how many times have you said I was a 'liar' or (gasp) 'an amateur' with respect to performance and aerodynamics - or completely 'clueless'?? or any of many others on this forum who challenge your strange belief systems.

Go back just through this Thread and see what you find?


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## Soren (Oct 24, 2008)

LoL Bill, stop relying on past events, I haven't called you anything for a LOOONG time, and the times I did call you something it wasn't until after YOU had started by calling me god knows what. Go back and read yourself if you dont believe me. You love provoking people by calling them names.



> Do you recall saying that the shock wave on the elevator started at the trailing edge?



Sure, by mistake, hence why I said the exact opposite at the beginning of this thread. Is that STILL too much to comprehend for you Bill ?


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## Soren (Oct 24, 2008)

> Do you recall your interpretation of the USAAF recount of 'snaking and hunt in the horizontal' as trash and associated that to 'only one or two' based on quality issues?



Nope that's a lie Bill, I relied on Hans Fey who says:


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## pbfoot (Oct 24, 2008)

Soren said:


> What are your sources exactly ? The reason I'm asking is that I have both the LW Ta-152H Me-262 POH, the Ta-152's was printed in January 1945.


The pilots


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## drgondog (Oct 24, 2008)

Soren said:


> LoL Bill, stop relying on past events, I haven't called you anything for a LOOONG time, and the times I did call you something it wasn't until after YOU had started by calling me god knows what. Go back and read yourself if you dont believe me. You love provoking people by calling them names.
> 
> 
> 
> Sure, by mistake, hence why I said the exact opposite at the beginning of this thread. Is that STILL too much to comprehend for you Bill ?



Insults From This week - Oct 18
*"Bill,

The study no doubt took in to account the structural integrity of the a/c, infact that is mentioned, otherwise it wouldn't be a serious study. However it was a serious in depth study Bill, not some amateur's go at trying to resolve some issue by assuming this and that.

And just because I don't have the report doesn't mean it isn't valid Bill, don't try to muddy the waters by suggesting such nonesense. I don't have to prove why the Me-262 could go supersonic in a dive, professional aerodynamicists have proven that it could by taking all aspects into account, otherwise it wouldn't be a serious study. So I am truly sorry Bill but I believe the professionals who took the time to study the issue in its entirety more than some hunch by a retired aero engineer.

So stop the twisting and turning and accept what the professionals have said on the subject, or are you suggesting you know better than them ? I aint*.

*"Bill that is a lie, I never mentioned the Mustang, all I said was I doubt that the Spitfire ever reached Mach .9 in a dive, I think Mach .82 seems a lot more reasonable.

Fabricating stuff definitely doesn't bolster your own credentials Bill."*

For your comments on the USAAF Report that the 262 had a Tendency to Hunt

From Post 136 this week

*"Only a few exhibited this behavior Bill, not all, which can be attributed to the varying degree of quality the a/c were being built to depending on which factory they came from*

From Today on the snaking issue - and you still haven't acknowledged either the POH you sourced or Kapitan Kurt Wendel's contradiction to your POV on this

*"I have a source for the fact that only a few Me262's exhibited the tendency to hunt: Me-262 test pilot Hans Fey, Allied Report, the site I referenced, written in big bold black letters."*


From this week on Professional Aero's and the standards they should meet in their opinions to conform to your reality


*"First of all Willy wasn't the designer, and secondly all that was concluded was that at Mach .86 the Me-262 would enter an untrollable pitch down dive, the increasing negative G-forces eventually breaking the a/c apart."*

More on your judgement of Willy M. knowledge of his prize creation

*"But how does that verify one comment of his on the Me-262 ? Like I said he didn't design the a/c and he wasn't part of the research team, so his total technical knowledge on the Me-262 would've been limited as he didn't work with the a/c every day."*

So much for Willy Messerschmidt being an unreliable opinion. I hope the Professionals that performed the Professional Study exceeded Willy's talents in order to make your short list.


From some of your earlier posts in which you exhibited your own professional credentials

*"It has been solidly confirmed by studies done in Germany that the Me-262 was perfectly capable of breaking the soundbarrier. 

"The Me-262 would be uncontrollable in pitch after 1,100 km/h, so diving to Mach 1 and surviving it would've been a great feat!"

"The problem which could occur was as KK describes if the pilot failed to stop the negative G the a/c automatically started to generate above .86+ Mach by trimming the tailplane.

"Regarding the discussion link you provided earlier: It is completely incorrect that the Me-262's airframe couldn't sustain the stress of a Mach 1 dive, as proven in studies done in Germany in 1999. That needs to be made clear."*

and more

*"The only way to get out of the negative G dive the Me-262 would start after 1,100 km/h was to utilize the movable horizontal stabilizer, the elevators and therefore also trim tabs being rendered useless because of turbulent flow.
"
A normal Me-262 in 1945 wasn't of very good quality Juha, so obviously there would be structural issues. But a Me-262 built to the standards of those made in mid 44 would be perfectly capable of breaking the soundbarrier without breaking apart. However, and yes I read the report as-well, distortion of the wings and popped rivets are to be expected.
"


"I aint talking down to you Waynos, I'm just telling you that the tests didn't conclude anything about the Me-262's airframe not being able to take the stresses of a Mach 1 dive. And the airframe could take it as established in studies done in 1999. The problem was the pitching down above 0.86 Mach, something which could only be corrected by use of horizontal stabIt is a case a false speed readings that's all, a known issue at very high subsonic speeds. The Spitfire couldn't go that fast without falling apart.ilizer trim, which I have heard the British weren't aware of, I think Hohun knows about this.

There are no miracles in physics mate, all things in aero can be measured, just like your sig lets us know."*


You may have a memory retention problem on the topics and your different positions depending on who 'caught you'. 

Regarding insults, you may simply have a different standard for insults for different people.


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## kool kitty89 (Oct 24, 2008)

Guys, I found something interesting in the previous article I mentioned (with the riveted elevator tabs) Gas Turbines Also, on the tabs, it turns out this article is based on US captured examples of Me 262's.

But in any case, (on pg 21 of the article) there's some very interesting info on the controls which largely explains the discrepancies in reports of the high speed characteristics. It seems early models had controls that became very stiff at ~500 mph, an extended stick was proposed to correct this. However, this doesn't apear to have ever been carried out; instead an additional large mass balance was fitted which seems to have solved the problem. 

Also, I'll double check, but neither "stiff controls" or directional snaking were experienced in the Wright field test, in fact iirc it was praised for its stability at high speed. (in shallow dives) Snaking wasn't mentioned either iirc.



And Bill, in a straight down 90 degree dive, there will be no pitch down behaivor, so that wouldn't be an issue. 


Soren, on the comparison to the Spitfire, in the dive trials, the Spit was fitted with al fully feathering prop to avoid overspeeding, minimise propeller related compressibility issues, and minimize drag experienced at high speed. 
The Me 262 would indeed still have thrust available at speeds where the Spitfire will have none (though both will be relying mostly on their weight). However, when the air ingested by the engines reaches supersonic speed, they will stall and flame out. (as Mutke experienced iirc) At this point the a/c is relying entirely on its weight alone for thrust. (although the engines had only been providing ~15-18% total thrust in a vertical dive)

Also, I retract my statement about the Spitfire being necessarily terminal at .89 Mach. It would be above its wing's Mcrit (for all sections much greater than ~10%) but given the thin tailplane the elevator may very well be fenctional. Additionally, while "tuck" is usually experience when an a/c's wing's critical mach number is exceeded, this isn't always the case (ie F-84 does the exact opposite) and the extremety of this characteristic veries as well. Assuming there is a tuck, it may be weak enough to counter with the stick or (if controls are too heavy) trim.

The critical Mach of the Spitfire's root section is probably ~.8 and increases as it tapers outward. (at 10% it should be arround .9 Mach) Due to the thicker section, the P-51D probably initially exceeds Mcrit of the wing somewhere arround .7-.75 mach. (iirc the earlier P-51's wing was somewhat thinner in section, as was the P-51H's)


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## Soren (Oct 24, 2008)

Bill,

I haven't called you names or called you stupid ever in this thread, unlike you. As for the "Bolster your own credentials" comment, don't forget who started that little scene, you as always.

Quit the insults Bill, stop saying I said something I didn't and stick with the facts.


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## Soren (Oct 24, 2008)

kool kitty89 said:


> Guys, I found something interesting in the previous article I mentioned (with the riveted elevator tabs) Gas Turbines Also, on the tabs, it turns out this article is based on US captured examples of Me 262's.
> 
> But in any case, (on pg 21 of the article) there's some very interesting info on the controls which largely explains the discrepancies in reports of the high speed characteristics. It seems early models had controls that became very stiff at ~500 mph, an extended stick was proposed to correct this. However, this doesn't apear to have ever been carried out; instead an additional large mass balance was fitted which seems to have solved the problem.
> 
> ...




My observations exactly as-well KK.



> Soren, on the comparison to the Spitfire, in the dive trials, the Spit was fitted with al fully feathering prop to avoid overspeeding, minimise propeller related compressibility issues, and minimize drag experienced at high speed.



Roger that KK but the prop would still act as nothing more than a brake at those speeds, esp. spinning around.



> The Me 262 would indeed still have thrust available at speeds where the Spitfire will have none (though both will be relying mostly on their weight). However, when the air ingested by the engines reaches supersonic speed, they will stall and flame out. (as Mutke experienced iirc) At this point the a/c is relying entirely on its weight alone for thrust. (although the engines had only been providing ~15-18% total thrust in a vertical dive)
> 
> Also, I retract my statement about the Spitfire being necessarily terminal at .89 Mach. It would be above its wing's Mcrit (for all sections much greater than ~10%) but given the thin tailplane the elevator may very well be fenctional. Additionally, while "tuck" is usually experience when an a/c's wing's critical mach number is exceeded, this isn't always the case (ie F-84 does the exact opposite) and the extremety of this characteristic veries as well. Assuming there is a tuck, it may be weak enough to counter with the stick or (if controls are too heavy) trim.
> 
> The critical Mach of the Spitfire's root section is probably ~.8 and increases as it tapers outward. (at 10% it should be arround .9 Mach) Due to the thicker section, the P-51D probably initially exceeds Mcrit of the wing somewhere arround .7-.75 mach. (iirc the earlier P-51's wing was somewhat thinner in section, as was the P-51H's)



Agreed.


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## kool kitty89 (Oct 24, 2008)

In Mutke's case, when did the engines flame out? (if it was after the plane "smoothed out" that wouldn't make sense inless the plane had not yet reached Mach 1)

Would the buffeting stop once airflow over entire wing had gone supersonic? (but before the entire aircraft had reached Mach 1)

Has anyoine found another site with Mutke's full story?


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## Juha (Oct 24, 2008)

KK
Quote: ” But in any case, (on pg 21 of the article) there's some very interesting info on the controls which largely explains the discrepancies in reports of the high speed characteristics. It seems early models had controls that became very stiff at ~500 mph, an extended stick was proposed to correct this. However, this doesn't apear to have ever been carried out; instead an additional large mass balance was fitted which seems to have solved the problem."

I doubt that that explain anything, of course it depend on altitude but 500mph (TAS) is too low to be relevant in this discussion. The problem we are talking about began in case of 262 at speeds over Mach .82. At normal speeds for ex Brown noted that flying was pleasant, control harmony good, with stick force per g of 6 lb at mid CG, but still Mach .84 was his max in dive.

Same to Spit, it was famous with its light elevators. Some Germans even thought that its elevators were too light, with some reason. Still 50kg pull needed at Mach .89 to keep the dive angle constant.

This thread is too long, probably most relevant is already said.

Juha


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## kool kitty89 (Oct 24, 2008)

I agree on all those accounts, but I was referring to the flight controls prior to entering the compressability region. (where the controls could get heavy stiff resulting from high -subsonic- flow over the control surfaces) Then there was the whole "snaking" issue. Both of which were in the context (as I understood it) of speeds of ~.80-.82 Mach, below the problem speed for the Me 262. (which was a bit off topic)


In any case, the behavior was "nose heavieness" (due to aft movement of the center of lift) at critical Mach, not loss of elevator control. The "heaviness" being too great to counter with the elevator (but the elevator still functioned). Changine the tailplane incedince should have restored proper trim, but as mentioned using the tailplane trim in dives was heavily warned against. (due to possibility of overcontrol)

The tail surfaces (and outer wings) all should be significantly thinner than the inner wing (they all apear to be around 8-9% t/c, though I'm only sure about the wing). So the elevator would still be functional well above the initial critical mach speed. (the ailerons and rudder as well; in the case of the ailerons should still work above .9 mach)


Another point that should be noted is that nowhere in the test flights (allied or Messerschmitt) were vertical dive tests attempted.


I'm still trying to get the complete story on Mutke's account though as I haven't gotten to read it in a while. (and the link is dead) According to wikipedia, he reduced power and experienced the flame-out while in the "calm," but the engines should have flamed out on there own as soon as the intake flow went supersonic. (unless the engine's intake and guide vanes somehow lowered the flow to subsonic prior to reaching the compressor) 

And reducing power too quickly could have been the cause of the flame-out.


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## claidemore (Oct 25, 2008)

Some quotes I found online, in Mutkes own words:


> "The airspeed indicator was stuck in the red danger zone, which is over 1100 km/hr.
> 
> I noticed that rivets began popping out of the tops of the wings.
> 
> ...



Mutkes reasoning of how he survived:


> "It's like when you pass a finger slowly through a candle flame and your
> finger gets burned. When you move it quickly, then nothing happens," said
> Mutke. "I went so fast through the buffeting area that it was only heavily
> damaged, both engines lost function and the rivets flew out of the wings."





> For the last several years, Otto Wagner, a professor at Munich's Technical
> University, has done computer simulations to try to verify Mutke's claim.
> He has been able to simulate the Me262 at Mach 1.02 -- just above the
> speed of sound -- but he says the basic data on the plane's aerodynamics
> ...



BTW, the Miles M.52 was a straight wing design (started in 1942) which did mach1.5 in October 1948 (unmanned).
In a completely unrelated topic, Hans Mutke also invented the female urinal.

kk- the wiki article says "but he had reduced power", but it is not specific about when. The assumption that he did so while in the 'calm' is because of the order the details are related in that article.


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## DerAdlerIstGelandet (Oct 25, 2008)

Well this thread has gotten out of hand.

I posted my warnings a while back as to what will happen. I do not have time at the moment, as me and my wife have to go to a Birthday party. When I get back effected parties will be notified. You know what I am talking about.


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## Juha (Oct 25, 2008)

OK KK
why they did not try 90 deg dives. IMHO because they had lost pilots in lower angle dives and knew that pilots were lost during near 90 deg dives in other planes. I think test centres try to keep their test pilots alive.

On snaking Brown in his Wings of the LW “The German development program had gone no further than the thickening of the trailing edge of the fin-and-rudder assembly and the provision of strips of sheet metal which were bent outwards along this edge. The overall effect was better than that obtained with Meteor I but inferior to that of the little Heinkel He 162.”

Juha


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## drgondog (Oct 25, 2008)

kool kitty89 said:


> Guys, I found something interesting in the previous article I mentioned (with the riveted elevator tabs) Gas Turbines Also, on the tabs, it turns out this article is based on US captured examples of Me 262's.
> 
> But in any case, (on pg 21 of the article) there's some very interesting info on the controls which largely explains the discrepancies in reports of the high speed characteristics. It seems early models had controls that became very stiff at ~500 mph, an extended stick was proposed to correct this. However, this doesn't apear to have ever been carried out; instead an additional large mass balance was fitted which seems to have solved the problem.
> 
> ...



*That would be speculation unless you have the data. My speculation is that Mcrit on the 51BCD wing was closer to .8+. IIRC the MK IV dive trials observed the shock wave charatceristics 'visibly' by the manifestaion of the ammo door deflection at .84 to .85 so the shockwave would have started earlier.

The P-51H wing was the NAA/NACA 66-(1.8) 15.5 and the BCD was a NAA/NACA 45-100 

The BCD was a .165 t/c at CL with a straight taper to .115 at tip
The H was a .155 t/c at CL with a straight taper to .120 at tip*

the BCD has 1 degree of negative incidence at tip (twist) and the H had 1.8

The differences are slight but lean to H for delay of Mcrit and both relatively fat wings compared to a 262 - at least outboard of nacelles

Further I would think Mcrit for the Spit wing would be at a lower speed than the 262 ~ .82+ Mach. Mcrit is when the local transonic flow first occurs - not the velocity for which the CMac has moved all the way aft


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## kool kitty89 (Oct 26, 2008)

Something to also consider (though probably minor), I believe the Me 262's fusalage was designed to have a semi-airfoil shape, and contribute a small portion of lift. So when the fuselage exceeds its critical mach number, this should result in trim changes as well.


And it turns out that the only mention of control properties at high speed (20-30 degree dives) in the Wrigh Field Me 262 handbook was that there was no elevator flutter, no mention of directional stability characteristics was made.


And, excuse my ignoracnce, but what does CMac refer to?


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## drgondog (Oct 26, 2008)

kool kitty89 said:


> Something to also consider (though probably minor), I believe the Me 262's fusalage was designed to have a semi-airfoil shape, and contribute a small portion of lift. So when the fuselage exceeds its critical mach number, this should result in trim changes as well.
> 
> 
> And it turns out that the only mention of control properties at high speed (20-30 degree dives) in the Wrigh Field Me 262 handbook was that there was no elevator flutter, no mention of directional stability characteristics was made.
> ...



Moment Coefficient about the aerodynamic center - usually 'located' around 1/4 c at the Mean Aerodynamic Chord. Thin symmetrical wings tend to mitigate the CMac changes at Mcrit


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## kool kitty89 (Oct 27, 2008)

Thanks. 

What I meant by my statement about the handbook was that it provided no pertinent information regarding the snaking issue. (I had remembered differently, but then I read through it again)

And that's 350 kts TAS?


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## davparlr (Oct 27, 2008)

kool kitty89 said:


> Thanks.
> 
> What I meant by my statement about the handbook was that it provided no pertinent information regarding the snaking issue. (I had remembered differently, but then I read through it again)
> 
> And that's 350 kts TAS?



I don't think TAS is ever referenced in performance limits for the pilot. TAS is primarily used in navigation. Indicated/Calibrated reflects the actual dynamic airflow over the aircraft (what the wings see). At high altitudes and airspeed, Mach becomes a crtitical factor also.

I would guess that, up until the 60's, very few aircraft had TAS indicators, although the Me-262 apparently had one.


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## drgondog (Oct 27, 2008)

kool kitty89 said:


> Thanks.
> 
> What I meant by my statement about the handbook was that it provided no pertinent information regarding the snaking issue. (I had remembered differently, but then I read through it again)
> 
> And that's 350 kts TAS?



Dave - you are right of course, and particularly to 99% of WWII fighters. From what I have read and heard the Germans built an airspeed indicator, some what successful, that indicated TAS.

My inference from the POH developed at Wright Psat was that the pilot was referring to TAS whether or not a post flight calculated number or IAS/TAS per the 262 airspeed indicator - in other words I have no real clue


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## kool kitty89 (Oct 28, 2008)

And the Me 262 had 2 needles on the indicator, a white one for normal IAS, and a yellow one for CAS so it's unclear which reading is sited sometimes. (I'm not sure how sophisticated the system was determining CAS though)


Slightly different, but the post war Meteor F.4 encorporated a Mach meter, which was important due to the ease at which it exceeded critical mach, with violent results in some circumstances. And though still somewhat primitive it gave pilots a good idea of when they were approaching the limiting .8 Mach. (which was increased slightly, along with much improved characteristics at critical mach, with the adoption of the new tail on the F 8 )


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## Soren (Oct 29, 2008)

The manual says the second needle lists TAS.


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## Soren (Oct 29, 2008)

> Read the excerpts from the Report. There are no discussions of flutter. There is a distinct comment about unsatisfactory flight characteristics above 350 kts.



Only if the CG was too far back. Otherwise the flight characteristics of the a/c were good at all speeds, which Hans Fey, Fritz Wendel and the Allied manuals also mention.


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## kool kitty89 (Oct 29, 2008)

Soren, you do not include critical Mach and above in "all speeds," right? 

You may disagree on the snaking issue, but I'm sure you'll agree that once you get into that realm, control is not "good." (certainly not in pitch)


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## drgondog (Oct 29, 2008)

Soren said:


> Only if the CG was too far back. Otherwise the flight characteristics of the a/c were good at all speeds, which Hans Fey, Fritz Wendel and the Allied manuals also mention.



Earlier - you did not admit to any cause except 'poor quality'. You still have difficulty in acknowledging that 'control was NOT good' in the transonic.

Maybe you will come around to that position based on the flight test and intelligence debriefings of the Messerschmidt test pilots?


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## Soren (Oct 29, 2008)

kool kitty89 said:


> Soren, you do not include critical Mach and above in "all speeds," right?



No, up to the top speed of the a/c = 870 to 900 km/h, where the handling of the a/c was excellent.



> You may disagree on the snaking issue, but I'm sure you'll agree that once you get into that realm, control is not "good." (certainly not in pitch)



Agreed.


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## davparlr (Nov 2, 2008)

Soren said:


> The manual says the second needle lists TAS.



This would make sense. Calibrated AS is Idicated AS corrected for installation error. With good CAS, IAS would not be needed.


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## Graeme (Nov 3, 2008)

Waynos said:


> The highest recorded speed achieved by a piston engined aircraft was mach 0.94 in an 84 Sqn Spitfire F.22 over Hong Kong in 1954 just prior to the Spit's final retirement from the RAF.



Evening Wayne.

Stumbled across an article describing an unintentional "rapid" descent (48,000ft in less than 60sec) by one Flt Lt Powles in 1952 piloting a PR MK XIX. *Mach 0.96*, although I don't know how they determined this if the dive was by "accident".

Either way, nice painting by Keith Woodcock of the event...


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## bada (Nov 5, 2008)

so, let me, a big noob, ask something here:
how can a prop plane reach such speeds, even in dive? 
From what i've read and only from that, at a certain point of the dive, the airflow hitting the propeller is higher than the speed of the propeller itself, at that point, the propeller becomes an air brake,not letting the airflow passing through.(or something like that)
So, what logic (and math) is behind the magic 0.94M dive of the spit with its 3meters wide airbrake? For me, such speeds with a propeller made in the 40's are simply male cow excrements.


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## delcyros (Nov 5, 2008)

Altough the M= 0.96 incident appears to be suspect from the first view, one has to carefully read the report first. I have not but I remain open for surprises.

Things which make it suspect in my subjective perspective:
A) -The Spitfire PR mk XIX was a service plane and not specially treated or enjoiing fine calibrated instrumentation.
B) -The Spitfire PR mk XIX has a lower crit Mach than the MK IX
C) -The high speed Spit mk IX used for dive tests earlier was equipped with a special low drag, fully feathering rotol airscrew to avoid overspeeding the engine, the PR mk XIX was equipped with stdt. prop.
D) -the PR mk XIX didn´t had one prop airbrake discs but two of them
E) -as far as I remember, the pressure increase alone broke the gear prop in M= 0.89 high speed dive tests on the Spit IX -while no such damage was reported in the PR mk XIX
F) -the cockpit carries it´s own shockwave and starts buffeting before the wing, contrary to description and art drawing.

....all on the level of speculation, I admit.

When it comes to breaking the sound barrier, I don´t think that any ww2 plane could really do this on a _normal_ condition.
It is one thing to go past the barrier -a fuselage seperated from the wings may achieve this- but it´s another thing to come back into normal speed regimes survive.
If I had the eggs to try and choose a plane to carry me there back, I would choose the Me-163. Fortunately I am just a nerd and not in any opportunity...


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## drgondog (Nov 5, 2008)

bada said:


> so, let me, a big noob, ask something here:
> how can a prop plane reach such speeds, even in dive?
> From what i've read and only from that, at a certain point of the dive, the airflow hitting the propeller is higher than the speed of the propeller itself, at that point, the propeller becomes an air brake,not letting the airflow passing through.(or something like that)
> So, what logic (and math) is behind the magic 0.94M dive of the spit with its 3meters wide airbrake? For me, such speeds with a propeller made in the 40's are simply male cow excrements.



It's complicated. First thing is the Propeller creates Thrust by virtue of changing the momentum of the freestream air as it passes through the blade plane. As you note the Propeller as a system also creates drag which increases dramatically at high speeds.

The question (and I don't have an answer) is a.) how much if any thrust in excess of drag remains in the .8-9 Mach range, and b.) how much drag is created by the total wing/body combination in the specific dive profile in question, c.) does the residual thrust of the propeller system plus the weight of the airframe slightly overcome the drag so that the airplane continues to accelerate, even if very slightly?

When all these forces are in balance the system will be in equilibrium (a very fast but constant velocity 'equilibrium').. so long as the aerodynamic (the 'q' ) loads do not cause a structural failure. 

So the questions regarding both the Spitfire Me 262 results are, in my opinion, 1.) what was measured accurately, and 2.) where are the limts to areodynamic loads to the airframe structure?

If the latter, then a large mass of parts will separate and become a cloud of debris.


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## drgondog (Nov 5, 2008)

delcyros said:


> Altough the M= 0.96 incident appears to be suspect from the first view, one has to carefully read the report first. I have not but I remain open for surprises.
> 
> Things which make it suspect in my subjective perspective:
> A) -The Spitfire PR mk XIX was a service plane and not specially treated or enjoiing fine calibrated instrumentation.
> ...




Delcyros - I tend to agree but confess that I have no clue what a.) the transonic characteristics were for the Me 163, no do I really have any insight to the specific wing design. I suspect that the 163 could not go supersonic because of the wing, despite the beneficial sweep angle

One of the ways flying wing designer's 'cheated' was to design a lot of camber into the wing to alter the CMac characteristics to compensate for a lack of a horizontal stabilizer. Unlike a 262 wing with a CMac causing a nose down on stall, the opposite is true for the type cambered wing normally associated with flying wings, and no elevator to compensate.

Also, IIRC the 163 had a pretty thick wing??

Recall that Glenn Edwards' fatal crash of the YB-49 when it was believed to completely roll about the wing axis, onto its back and go into a spin - after it stalled out. That Cardenas survived the first experience was a miracle.

Even today we are fooling around with subsonic a/c despite 70 years of development. The B-2 flight control systems allegedly PREVENT any possible stall attitude that can be initiated by the pilot.

Everything I just said is 'old memory' so take with a grain of salt.


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## ponsford (Nov 5, 2008)

I was browsing _Spitfire the History _ and came across this information of a Spitfire 21 (LA188) which was equipped with a Mach meter and dived to Mach .89.


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## Graeme (Nov 5, 2008)

Anyone know if "Mach Buster" ever came close to its namesake?...





Photos: Rose Mach Buster Aircraft Pictures | Airliners.net


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## Juha (Nov 5, 2008)

Hello
I have read on Powles dive from two articles a while ago and I also have my doubts but at least atmosphere conditions are known because Powles took up measurements during his climb, that was one of the purposes of the flight, IIRC the main purpose.
To Delcyros comments a couple corrections:
RAE test plane(s) in high speed dives was/were PR XIs and later Mk 21 not Mk IXs
Quote:"E) -as far as I remember, the pressure increase alone broke the gear prop in M= 0.89 high speed dive tests on the Spit IX -while no such damage was reported in the PR mk XIX"

RAE made numerous dive tests up to speed .89 and usually without damage to the plane (PR XI) but there were two exceptions, Martindale's .91 dive on 27 April 44 when reduction gear and propeller broke away and later, again when Martindale was the pilot when he suffered a complete supercharger failure and engine fire.

And I don’t understand the following:
Quote:"D) -the PR mk XIX didn´t had one prop airbrake discs but two of them"

PR XIX didn't have contra-propelling propeller but normal 5-blade propeller

Juha


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## delcyros (Nov 5, 2008)

my mistake Juha, thanks for correcting me.

Additional damage received on the PR mk IX was a good deal of engine cowling carried away by buffeting forces. I am very surprised that no such damage occurred on the 1952 M=.96 dive albeit the PR mk XIX would be subject to more severe buffeting effects into the compressibility range.


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## Juha (Nov 5, 2008)

To me max speed achieved by Spitfire is Mach .89 (or .91, see my next message) because it was highest speed measured scientifically when the a/c stayed together incl. the propeller. And one must remember that the Spit was PR XI, so it was without protruding gun barrels, ejection chutes, overwing blisters and bullet-proof windscreen and with fully feathering propeller. Probably max possible to standard fighter version was appr. Mach .85. And that is only a guess, I'm not aerodynamist but a historian.

Juha


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## Juha (Nov 5, 2008)

Hello Delcyros
It easy to become confused on these dive tests, I just checked Dennis' Royal Aircraft Establishment at war at according to it max recorded speed for PR XI was Mach .91, again flown by Martindale. It seems that that dive was made earlier than the famous 27 April dive.

Juha


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## drgondog (Nov 5, 2008)

Juha - just a note. First I subscribe to your basic premise regarding achievements made with verifications and adequate instrumentation are the only ones worth debating.

As a former aerodynamicist/Structural analyst/airframe designer (long retired and 'old') PREDICTIONS regarding propeller driven a/c near Mach 1 would be as much art as science for many of the reasons well discussed in this thread.


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## kool kitty89 (Nov 5, 2008)

drgondog said:


> Also, IIRC the 163 had a pretty thick wing??



At least at the root, according to: The Incomplete Guide to Airfoil Usage it had: 
Me 1.8 25 14-1.1-30 (root) NACA 00008-1.885-20 (tip)

So the root was certainly thicker than the Me 262's (and possibly similar to the Spitfire's with sweep taken into account) and uses an airfoil with a lot of chamber. The tip is thinner than the Me 262's however (and of a similar symmetrical type as the Me 262), so without knowing how the wing tapers (and where the airfoil changes -I'd guess it's where the slots start) it's difficult to make comparisons.


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## claidemore (Nov 6, 2008)

Spit XIX's were initially fitted with 5 blade Rotol props, but later versions had the contra-rotating prop, not sure if factory fitted or retro fitted. Two pics below, showing either prop.


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## kool kitty89 (Nov 16, 2008)

The greater weight of the griffon powered versions should also counter the added drag from the increase in prop blades.


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## Juha (Nov 16, 2008)

Hello
Powles Spit had normal 5 blade prop, at least according to photos I have seen.

Juha


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## delcyros (Nov 18, 2008)

The Me-163 has quite thick wingroots and wooden wings (structurally questionable in the transsonic regime) but this is why I would choose her in a dive:

A) The Me-163 has a smaller frontal area than everything else in question
B) The engine delivers ca. 2 tons of thrust regardless of altitude (unlike jet engines). It´s powerplant in fact accelerates any serial Me-163B past it´s critical Mach speed at all but low altitudes* in level flight, let alone in a dive from very high altitude as one might need to engage in order to hit Mach 1 in that A/C. The rocket engine also don´t shuts down following a Mach stall.
C) There is no washout at the wingtips and no stabilizer to carry it´s own (additional) shockwave
D) the (comparably) thick wings do allow more strength structurally (well it´s wood, so it needs it, don´t know what Mach 1 would mean thermally but if You have the right wood and the right glue agent with the right treatment perhaps?) and are framed with tight subdivision. 
E) Following earlier tests, the vertical rudder was structurally enforced to deal with increased forces of transsonic regimes and the elevons were reshaped for the same reason 

*) High speed level flights carried out at 4000m had to be abandoned after reaching M=0.85


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## Soren (Nov 19, 2008)

I still say the Me-262 came the closest, although there is a possibility the Me-163 could go faster and infact went supersonic. But structurally the Me-262 is the soundest of any of the a/c who came close, the problem is the pitching down above Mach 0.86 and the possible stall of the engines.


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## Juha (Nov 19, 2008)

Soren
in Me 262 the pitching down began earlier, Mach 0.84 was the max E Brown thought he could handle, in fact he dived faster in Spit PR XI (Mach 0.86)

Of course while testing the behavior of Me 262 in dive Brown only needed to get enough in troble to confirm German findings but when he made his dives in Spit XI he was a member of a team studing a/c behaviour at high Mach numbers (at the time) but also then other members of the team achieved higher speeds.

Juha


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## drgondog (Nov 19, 2008)

Soren said:


> I still say the Me-262 came the closest, although there is a possibility the Me-163 could go faster and infact went supersonic. But structurally the Me-262 is the soundest of any of the a/c who came close, the problem is the pitching down above Mach 0.86 and the possible stall of the engines.



While I don't disagree any point, what makes you say the 262 is structurally 'sounder' than say the 163? 

The shorter wingspan and deeper chord of the 163 certainly gave it a possibility of a much stronger wing, and the lack of horizontal stabililzer removes loads from the tail. 

Getting rid of landing gear and associated cut outs of skin and structure adds even more probability of being stiffer and stonger. 

Lack of sustained input at high frequency from a jet engine takes out every harmonic input except flutter and I don't recall that was a problem..

So why would the 262 be deemed 'sounder structurally'??


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## kool kitty89 (Nov 19, 2008)

Well, the Me 163's wing is made of wood, but this alone is difficult to speculate with.


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## Soren (Nov 20, 2008)

drgondog said:


> While I don't disagree any point, what makes you say the 262 is structurally 'sounder' than say the 163?
> 
> The shorter wingspan and deeper chord of the 163 certainly gave it a possibility of a much stronger wing, and the lack of horizontal stabililzer removes loads from the tail.
> 
> ...




All valid points Bill and I agree, the only reason for my comment is the knowledge that the Me-163 was constructed partly of wood and that the Me-262 was all metal and features one of the strongest wing structures of all a/c of WW2. The Me-262's wings were purposely built extremely strong because of the fact that they needed to support the engines and the fact that the a/c was going to be flying much faster than any previous a/c, so the G-loads in maneuvers were logically going to be much higher. So although thin the Me-262's wings were among the strongest put on any a/c during the war.


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## drgondog (Nov 20, 2008)

Soren said:


> All valid points Bill and I agree, the only reason for my comment is the knowledge that the Me-163 was constructed partly of wood and that the Me-262 was all metal and features one of the strongest wing structures of all a/c of WW2. The Me-262's wings were purposely built extremely strong because of the fact that they needed to support the engines and the fact that the a/c was going to be flying much faster than any previous a/c, so the G-loads in maneuvers were logically going to be much higher. So although thin the Me-262's wings were among the strongest put on any a/c during the war.



Good reasons to speculate - both ships designed for very high 'q' so hard to say one way or the other.


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## Waynos (Nov 25, 2008)

Is there any meat to the rumours of the Lippisch P.13B being tested supersonically? I have seen this a couple of times but have to say I'm very sceptical.


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## delcyros (Nov 26, 2008)

Well, the Lippisch P 13b was extensively tested subsonically as well as in supersonic condition in the Darmstadt supersconic wind tunnel. As a model, of course...


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## johnbr (Nov 27, 2008)

Dr Lippisch said that the P.13 was destroyed in a air raid before it was finished.


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## Soren (Nov 27, 2008)

The Allies captured one intact so I doubt that.


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## kool kitty89 (Nov 28, 2008)

Soren, it was the DM-1 glider that the US captured (and resulted in Convair's delta projects starting with the XP-92). This glider was very similar to the P.13a design.

The P.13b was a different aircraft. Lippisch Li P.13b Luft '46 entry

Further adding to confusion, the Lippisch P.13 was a completely unrelated project of a push-pull high speed piston engined bomber. (2x DB 605's)


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## Soren (Nov 28, 2008)

You're right, it was a glider version they captured, I was actually thinking of the P.13a. But Delcyros's statement still stands, as like he said it was small scale windtunnel models which were extensievly tested at sub supersonic speeds.


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