Bf109G-6 Question!

[DonL]

Because I defend the webpage of Kurfürst?
What has he done wrong on his webpage, or what is wrong with his sources?
Are his sources wrong? Is there any evidence?
I don't refer to his behavior at different forums!

I have sometimes my problems with the performance charts of wwii aircraft performance.

You can also judge me, because to me, the best guitarist is Slash, the hottest chick is Fergie and the hottest model was Stephanie Seymour.

 

[Milosh]

There is nothing wrong except it is always the best he puts on his site. It is what he doesn't put on his site > nothing negative.

Are you saying that Mike forged the documents?

 

[GrauGeist]

Look, if you guys have problems with the authenticity of aircraft data on either sites, take it up with the owners of those sites and keep it out of the threads...all it does is start arguments and ruins a good discussion.

Seriously

 

[DonL]

And what is with the difference between the clearence of the 1,42 ata boost?

One website claimed Feburary 1944 and the other page give primary sources about September/October 1943.
That's a major difference!
So only why the primary sources comes from Kurfürst, they are wrong and we must believe in an anglo website?

 

[Aozora]

Just got this info on Erla's Heiterblick plant that built 32% of all Bf 109s (note, content is Anglo):

 

[Aozora]

Production flow charts:
Before dispersal:

After dispersal:

USSBS Report via MilSpecManuals

 

[stona]

Deleted

 

[stona]

we must believe in an anglo website?

Dear oh dear!

Why don't you investigate the 'anglo (US)' origins and influence on both Focke-Wulf and Lorenz. Here's a few clues. Sosthenes Behn. International Telephone and Telegraph Corporation. US Patent Office. Ludwig Roselius. HAG Group.

Business is business

Have fun!

Cheers

Steve

 

[Glider]

Re clearance of 1.42 boost. I don't know the exact detail and am not pretending too but there is one aspect which might be taken into consideration. When we are talking about mid late 1944 on the German problems had more to do with fuel and training for pilots not extra aircraft which were being churned out by the factories.
If I was in charge of a unit and the paper pushers gave me an order restricting the boost that should be used, I would be sorely tempted to 'forget' the instruction and carry on, after all spares don't seem to have been the problem. I may well reduce the time between checks to reduce the risk and make everyone aware, but if it gave my pilots who were under all sorts of disadvantages a better chance I would be tempted.

There are all sorts of examples of units in the field making unauthorised modifications and I don't see why this would be any different.

DONL I don't know if you are aware but your set up isn't receiving any PM's you might want to check it out.

 

[FLYBOYJ]

we must believe in an anglo website?

You're a friggin idiot, I'm sick of your bantering and moronic comments. I gave you plenty of chances but you continue to be flat out STUPID. Enjoy cyberspace!!!

 

[Glider]

Looks like his sign on has a bigger problem than I thought

 

[FLYBOYJ]

Now I hope this thread continues with no further issues

 

[dedalos]

Now I hope this thread continues with no further issues

By saying "further issues" you mean any opinions in support of german aircrafts?
Now with the elimination of Don L you have banned almost every single LW friend .
Flyboy J . The American expression of freedom of speech

 

[kettbo]

First of all, My english is not good. plz understand this.


Most of documents and flight sim game discribe Bf109G-6 had bad maneuvering. but I cannot understand.

Bf109G-6's gross weight is only 3350kg. It has no GM-1 Booster, Pressuerized cabin. Everything changed from Bf109G-2 is FuG16 radio set and MG131 Maschinengewehr.
The bulge reduced speed of G-6, but it didn't couse of bad maneuvering.

What factor makes Bf109G-6's bad maneuvering? I cannot find about this.

for some reason, a few of the games are designed with the Bf109G-6 as only built with the underwing gun pods or use the data for a plane with cannon pods, then some of the games use the older performance figures. seems to be my recollection

 

[FLYBOYJ]

By saying "further issues" you mean any opinions in support of german aircrafts?
Now with the elimination of Don L you have banned almost every single LW friend .
Flyboy J . The American expression of freedom of speech

I have no dog in this fight and this is a private forum. Act like an idiot and you're gone. BTW I am a great LW fan, so what's your point?

You dont like this forum, leave, that simple!

This has nothing to do about "The American expression of freedom of speech." It has everything to do with "The stupidity and ignorance of the internet." You're a prime example.

BTW-"aircraft" in the plural still "aircraft."

Now go slam your head against a big rock until you bleed profusely!!!

 

[Koopernic]

It's an internet 'factoid' which grows more insidious by repetition. Like deep rooted weeds, you can cut the tops off but the damned things keep coming back.

Cheers

Steve

Hi Juha and stona,

I would regard a 'factoid' as a piece of correct information that nevertheless is taken or presented out of context, I'm sure I didn't do that. I intended to and believe I presented the information in context.

The aileron reversal speed of the Spitfire was calculated at 540-580mph, at speeds above that point the aircraft could roll in the opposite direction. Did that actually happen in a real dive? It has on some aircraft as I found out in researching this issue. If a pilot did apply that level of deflection on the Spitifre its possible the pilot did not survive that incident, the concern by the engineers for his safety was so high test pilot Jeffery Quill was told not to test this limitation. This is an engineering calculation, a figure of merit confirmed by real world measurements but a very real and practical one. In practice its effect was to undermine the Spitfires Roll rate at high speed rather than cause an actual reversal. There were clearly many effects undermining aircraft roll rate; one is the aileron reversal speed, another is stick forces. In the case of the Spitfire I would argue the low stick forces it was noted for due to its thin wing being less susceptible to shock wave formation was undermined by the wing twist stemming from wings aero-elastic properties. The wing despite being strong twisted in the opposite direction to the aileron. Note also we have two spitfire aileron sizes, the smaller ones on the Mk VIII that were better at high speed and the larger ones on the Mk IX better at lower speeds.


Flying to the Limit: Testing WW II Single-engined Fighters
By Peter Caygill

It was enough of an concern for the aileron reversal speed to be carefully improved such in the F.21 Spitfire it was improved by 47% to 840mph (presumably without compressibility effects.). The Mk XVIII Spitfire had a strengthenedthe old wing design achieved by using a single piece tapering main spar rather than a telescoping spars and stainless steal stringers, so it wasn't merely extra strength to cope with weight growth that was required, that had already been achieved.

540mph and 840mph are very specific facts. Aileron reversal problems continued to plague even modern swept wing aircraft. It does seem that the aeroelastic properties of Spitfires was somewhat lower than its key contempories. Hence if say the Lockheed hydraulic assisted boost used on the P-38J was fitted to the Spitfire prior to the Mk.21 there would be little point.


The end result is that the Me 109 and Spitfire had about the same roll rate at higher speeds. Neither aircraft was good at speed, both were modest compared to their contemporaries.

Me 109 and Spitfire pilots do not complain or boast about being out rolled by each other but Spitfire pilots did complain about that happening when they encountered the Fw 190. I note that the Me 109 had an excellent roll rate at low to medium speed. Aspects of the Spitfires roll rate were initially inferior and were improved when it had its fabric covered ailerons replaced with aluminum sheet and also latter friese ailerons added to reduce loads but this did not address the aileron reversal speed associated with the aeroelastic properties of the wing.
What I do regard as a factoid is the aileron deflection versus stick force measurements for the Me 109 being quoted as proving the Me 109 was ummanouverable. This is because measurement that is part of a larger set of data that helps us understand roll rate limitation on the 109.

The proper way would have been to plot aileron deflection, stick force, roll acceleration and roll rate on a tachograph plot in an appropriately instrumented Me 109 and Spitifre and to compare the two to see why both were different but performed similarly in the roll plane. We don't have such a nice clear report from the various aircraft.

The primary structure of the Spitfire was a main spar at about the quarter chord (25%) point with a D section leading edge sheet forming a rigid member. The 25% is where the lift and forces are concentrated. There was a second, smaller spar of course at the rear that added strenght as well. To me it looks like the aileron had a large leverage around that. The Me 109 had a main spar at about the 50% point with 2 smaller spars to either side, the main spar went through considerable detours to clear the wheel well retraction points. The Fw 190 had two main spars with thick sheet metal between them, likewise the P-51.

I should point out that by placing the main structural element about the quarter chord point the Spitfire had excellent stall properties, Fw 190 wing twist could lead to a sudden wing tip stall as a Focke-Wulf report into the Fw 190A6 notes, though I note I am reading a report by an American Navy Pilots praising the well enunciated stall of the Fw 190D9 under maneuver suggesting that the issue may have been addressed in the A8/A9/D9.

I should point out that the use or planned use of servo tabs on the Messerschmitt 109 was clearly designed to address the stick force issue. It was common among latter German aircraft and a highly refined version known as the geared spring servo tab was developed by the US NACA and fitted to late war fighters such as the corsair and hellcat. They can be difficult from the point of view of flutter and reducing 'feel' too much such that the airframe could be overstressed.

 

[stona]

Aileron reversal and reduced effectiveness (due to the high input forces required or aeroelastic properties of the wing) are obviously not the same thing. Quill diving the prototype at more than 450 mph did not encounter aileron reversal. The calculated figures were posted above. These are outside the operational limitations of the type. Pushed beyond it's limits there were many other problems for the Spitfire, just as there would be for any other type so abused.
Nobody is disputing the aeroelastic properties of the various versions of the Spitfire wing. The problem is that this has been extrapolated in internet world into a problem of aileron reversal under normal operating conditions.
It is worth remembering that the Spitfire wing (like the Bf 109s) was designed in the mid 1930s for a 350 mph fighter in something like the 1,000 hp range. The fact that both wings eventually coped with parametres well above this speaks volumes for their designs.

Are you sure that the Mk XVIII had the new spar rather than the seven (IIRC) part version. There was strengthening of the wing to cope with the increase in weight but otherwise it was similar to the Mk XIV. The decision to ask Messrs Booth to experiment with the production of a 'single extruded taper tube' as the main component of the main spar was taken in relation to the Mk 21 as far as I can tell. A similar two part version was also mooted for the Seafire, but was never produced except experimentally.

Cheers

Steve

 

[Juha]

Hello Koopernic
As Stona wrote aileron reversal and reduced effectiveness due to the high input forces required or aeroelastic properties of the wing are not the same thing. And in spite of the wing aeroelastic problems British significantly improved Spit's ror by introducing metal covered ailerons in 1941. OK according to my understanding 109F also rolled better than 109E.

And
"The end result is that the Me 109 and Spitfire had about the same roll rate at higher speeds. Neither aircraft was good at speed, both were modest compared to their contemporaries. "

Even if Spit and 109 had much common in fact according to DVL wing twist test on Bf 109F-2, which also gave roll rate for the plane, 109F-2 rolled worse than the standard wing Spitfire V shown in the figure 47 in NACA 868 report at all speeds, paramets used: around 3km height and with 50lb stick force. The difference was marked (over 10deg/sec) at IAS speeds under 260mph, small (under 5deg/sec) from 275 to 300 mph IAS. It maxed at Spit's max roll rate speed 200mph IAS, being 33deg/sec., and was smallest at 109's max roll rate speed 280mph IAS being 3deg/sec. At 390mph IAS normal wing Spit rolled 14deg/sec faster than the F-2 used by DVL. And according to the NACA report clipped wing Spit greatly outrolled the 109F-2 through the whole speed range.

One must remember that 109G had a bit stiffer wing than 109F, its wing skin at roots was a bit thicker.

 

[Koopernic]

Hello Koopernic
As Stona wrote aileron reversal and reduced effectiveness due to the high input forces required or aeroelastic properties of the wing are not the same thing. And in spite of the wing aeroelastic problems British significantly improved Spit's ror by introducing metal covered ailerons in 1941. OK according to my understanding 109F also rolled better than 109E.

And
"The end result is that the Me 109 and Spitfire had about the same roll rate at higher speeds. Neither aircraft was good at speed, both were modest compared to their contemporaries. "

Even if Spit and 109 had much common in fact according to DVL wing twist test on Bf 109F-2, which also gave roll rate for the plane, 109F-2 rolled worse than the standard wing Spitfire V shown in the figure 47 in NACA 868 report at all speeds, paramets used: around 3km height and with 50lb stick force. The difference was marked (over 10deg/sec) at IAS speeds under 260mph, small (under 5deg/sec) from 275 to 300 mph IAS. It maxed at Spit's max roll rate speed 200mph IAS, being 33deg/sec., and was smallest at 109's max roll rate speed 280mph IAS being 3deg/sec. At 390mph IAS normal wing Spit rolled 14deg/sec faster than the F-2 used by DVL. And according to the NACA report clipped wing Spit greatly outrolled the 109F-2 through the whole speed range.

One must remember that 109G had a bit stiffer wing than 109F, its wing skin at roots was a bit thicker.

The NACA 868 report gives no information on Me 109 roll rate at all. There is no comparison. It is, thanks to Cranfield University, mirrored here:
http://naca.central.cranfield.ac.uk/reports/1947/naca-report-868.pdf See page 166 figure 47.


For the German DVL report we have:

200 kph = 45 deg/sec (0.8rad)
300 kph = 68 deg/sec (1.2rad)
400 kph = 83 deg/sec (1.45rad)
480 kph = 20kg/44lbs limit
500 kph = 88 deg/sec (1.55rad)
600 kph = 91 deg/sec (1.6rad) - peak value
700 kph = 56 deg/sec (0.98rad)
800 kph = 23 deg/sec (0.4rad)


Te stories about the roll rate of the aircraft being set in cement somewhat hyperbolic. The above data is in TAS and as the document show the tests are made in H=3km (H = Höhe = altitude) about 10000ft.

In in 3km alt :

600km/h TAS = around 510km/h IAS = 91°
700km/h TAS = around 595km/h IAS = 56°
800km/h TAS = around 680km/h IAS = 23°


Me 109F2 at 595kmh (370mph) IAS, 3000m (10000ft) the Me 109F2 is rolling at 56 degrees sec (30kg or 66lbs stick force)
Sptifire V at 595kmh (370mph) IAS, 3000m (10000ft) the Spitifre V is rolling at 56 degrees sec (50lbs stick force)

There really is no significant difference.

For comparison the P-51B and Fw 190A are both rolling at 95 degree/sec at 50lbs according to US tests (which have to be taken with a little suspicion as they are from captured aircraft that may have been out of condition given reports or aileron flutter).

I suppose we could scale up the Spitfire roll rate 32% to 73 degrees sec but I strongly suspect that due to elasticity the actual roll rate would not scale up proportionately.

If we compare at 600kmh/312mph the Me 109 actually rolls faster 91 degrees/sec as opposed to 70 degrees/sec for Spitfire (Albeit 66lbs stick force) whereas the Fw 190 is managing 125 degrees/sec which clearly is significant. (remember this is roll rate not acceleration into the roll ie bank rate, which is another factor). The slower you go the better the Me 109 becomes compared to the Spitfire.

The overly maligned P-40 is also considerably out rolling the Spitfire.

I would argue that applying more stick force might make the Spitfire's relative performance even worse because of the aeroelastic issue.


It's clear to me that Supermarine Engineers and Test pilots understood the issue as did the RAF but were reluctant to disrupt production.

Subjectively we can say that the Spitfire suffered from both high aileron stick forces and a relatively low control reversal parameter, the high stick forces were reduced by adding in metal covered friese ailerons (friese were also on the Fw 190 and Me 109F/G/K though fabric) but the elasticity remained and was not attended to in the manufacturing program till the Mk.21 which saw service in the final months of the war. The Spitfire's actual aileron forces were actually probably not that high, perhaps less than most for the same degree of deflection, but given the thin wing but the aircraft never took advantage of that.

For the Me 109 we can say much the same, it possibly had more stick force but the same or slightly better control reversal.

Such things can come out of simple things as aileron size, bigger ailerons are better at low speed but a disadvantage at high speed. I note that the Mk VIII had smaller ailerons and so it would give a different roll characteristic and I believe that wing was used on the Mk XIV.

 

[Juha]

Hello Koopernic
but the 600km/h 91deg/sec was calculated, in fact the pilot couldn't use more than 20kp force to the stick because of the narrowness of the 109 cockpit. The best ror was achieved at 500km/h when the full 360deg roll took 4.5sec. At 600km/h the full 360deg roll took 7 sec.


Spit maxed at 200mph IAS 105deg/sec (normal wing) and 150deg/sec (clipped wing) at 10.000ft according to NACA so to me your claim " The slower you go the better the Me 109 becomes compared to the Spitfire." doesn't hold water.

And P-40, especially the Tomahawks with lighter wing armament were famous for their high max ror, especially at medium speeds.