# MW-50 Bf 109s Vs Fw 190 A



## Jenisch (Mar 19, 2012)

Hello, 

Theoritically, the 109 seems to have advantage, specially at high altitudes. However, many pilots preffered the Fw 190. Light controls, confortable cockpit, excellent firepower among others things are pointed as reasons. 

During the war, assuming combat at low and medium altitude, the 190 A could compete with the 109? I always read criticism of the Luftwaffe in high altitude for Antons, but never in low and medium. In Osprey's Fw 190 Aces of the Eastern Front, despite Russian claims the 190 was inferior to the 109, there's not a simple complaint about inferior performance from the German pilots.


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## davebender (Mar 19, 2012)

That's true for both the Fw-190A and Me-109. Both aircraft performed well below 20,000 feet where most Russian front combat took place.

Internal fuel capacity was probably the greatest Fw-190 advantage when fighting in Russia. Pilots such as Hartmann loved the Me-109 but they had to fly with one eye on the fuel gauge.


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## Jenisch (Mar 19, 2012)

Not only internal fuel capacity, but external as well. The 190 could carry two drop tanks, instead of one for the 109.


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## davebender (Mar 19, 2012)

External tanks are normally dropped at the start of aerial combat. Internal fuel is all you have to fight the battle and fly home. Hence the reason internal fuel is much more important then external fuel.


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## Denniss (Mar 19, 2012)

The standard Fw 190 could carry one drop tank, just like the standard Bf 109. Only some special variants could carry two or even three drop tanks.
The Fw 190 may have more internal fuel capacity but its engine also burned more fuel.


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## davparlr (Mar 19, 2012)

davebender said:


> External tanks are normally dropped at the start of aerial combat. Internal fuel is all you have to fight the battle and fly home. Hence the reason internal fuel is much more important then external fuel.


 
A very important point many people tend to miss.




Denniss said:


> The Fw 190 may have more internal fuel capacity but its engine also burned more fuel.



My data base shows the Bf-109 with 106 gallons internal and the Fw-190A with a 140 gallons internal. Just comparing hp, this gives the Fw-190 only slightly better operational fuel quantity. The limited internal fuel on the Bf-109 (and spitfire) severely limited operational flexibility, limiting them to front line offense and point defense. In comparison, the P-51 had 180 gallons just in the wing tanks, not including the 85 gallon extended range fuselage tank, which allowed much deeper penetration into enemy airspace and/or more endurance above the battlefield.

My data base also shows the Fw-190A faster than the Bf-109G at all altitudes up to 30k. At low altitudes the Fw-190 outclimbed the Bf-109 but above 10k the Bf-109 climb was much better.


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## davebender (Mar 19, 2012)

> Fw 190 may have more internal fuel capacity but its engine also burned more fuel



*Internal fuel capacity.*
340 liters. Me-109G
535 liters. Fw-190A. 57% more then Me-109.
1,100 liters. Fw-187 (early model). 1,300 liters for proposed later model.

The Fw-190 undoubtedly burned more fuel then a Me-109 but I don't think it burned 57% more.

Even with two engines I suspect the Fw-187 could stay in the air a long time using only internal fuel. Such a missed opportunity.....


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## GregP (Mar 19, 2012)

From my time studying WWII fighters, I am left with the following impressions:

1. The Fw 190 had wonderful ailerons and could do an aileron roll that would rip the wings off an Me 109 or Spitfire at 400 mph. The landing gear made for very good rough-field jandling. It has great aramament and a reliable engine, though it did not run as long on boost as many in here believe. It made for a stable gun platform and the radial offered good protection for the pilot from frontal shots. It had an average to slightly poor rate of turn. That is, the elevators could not make the Fw 190 turn with the other fighters. It was in its element at anywhere from 250 - 420 mph and was a very poor turner above 400 mph, though stillr etaining a good roll rate.

2. The Me 109 (or Bf 109 if you prefer) was an excellent attack aircraft at low to medium speeds. It developd a very good rate of climb at low aispeeds, around 180 - 200 mph, It was a very good fighter at 180 . 280 mph. The armament was not great, but mostly were mounted on the fuselage, where gun synchronization is a factor, and most Luftwaffwe pilots were of the opinion that one gun in the fuselage was worth two in the wings. The 109 had nice controls at 180 - 250 mph but tended to "heavy up" above 280 mph and, at 380 mph, the stick was almost frozen in place with only slight roll and pitch available. If you were fighting an me 109 at 400+ mph, it was traveling in very straight lines. There was not rudder trim, and the Me 109 rolled much better to one side than the other as a result of the pilot having a tired right leg.

Much has been made of the narrow landing gear, but the Me 109 designed to operate from grass fields. If operated there and if the pilot were trained by the L:uftwaffe, the ground handling was not a big issue. On pavement, though, it is treacherous. The Achilles heel for the Me 109 was short range and relatively poor visibility forward and right or left. One can see pretty well straight forward or straight out to either side, but the windscreen design for forward and left or right is awful. I have sat in a Messerschmitt 109 cockpit at least 150 times and I still can't see how they fought with that canopy design.

That being said, the Me 109 was the mount for the three top scoring Luftwaffe Aces, for Marseilles in North Africa, for the top Finnish pilot, and for top pilots from Romania and Croatia. How bad can it have been? In later models, the Me 109 was given a good high-altitude capability and was certainly better than the Fw 190 and high altitudes until the Fw 190D and Ta-152's came along (though the Ta-152 never did see much service). However, it still had the tendency to heavy-up on the controls at high speeds, making it fast but unmaneuverable when actually going fast.

All in all, the two aircraft gave the Germans a great one-two punch in the fighter department, with many pilots voting for both types as the better of the two. From combat record, it is Me 109 hands down ... but that mainly has to do with time of service and employment by group and front.

At various times, both the Me 109 and the Fw 190 wrested the advantage from the Spitfires, but the Spitfires were developed, as were the two German planes, so the advantage tended to rotate back and forth among them.

Bottom line, the "better" of the two would depend on the mission, If you just wanted to knock down bombers, the heavier armament of the Fw 190 was probablouy the better bet. In fighter versus fighter combat, you can get opinions both ways from the best pilots who ever strapped into a fighter.

Naturally, there are those wh think this combination was the best in the world, though they were beatten by the Allies. When I think of top fighters of WWII, I include both the Fw 190 and the Me 109, as wellas the Spitfire, the P-51 Mustang, the Yak-3, the La-5 / 7, the P-47, the F6F, the F4U, and the P-38. Picking the "best" will involve the mmission, the range, and the circumstances ... and you'll not get any two people to agree.

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## Jenisch (Mar 19, 2012)

Thinking well, the correct Anton for compare against the MW-50 109's would be the one with the 2,400hp engine that never went into production, isn't?


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## davebender (Mar 19, 2012)

> Naturally, there are those wh think this combination was the best in the world, though they were beatten by the Allies.


I think poor Luftwaffe logistical planning had a lot to do with it. 

Prior to 1941 there was plenty of fuel. New pilots received thorough training. It was common for pilots in operational units to fly several missions per day. Many historical accounts suggest they flew from dawn to dusk during periods of intense combat. Aircraft landed just long enough for more fuel and ammo. Even a small number of aircraft can produce an impressive number of combat sorties under those conditions.

By 1942 Luftwaffe pilot training was short of fuel. Fewer replacement pilots and they were less well trained.

By 1943 even priority missions such as the Kursk offensive had only two thirds of required fuel and German pilot training was in a nose dive for lack of fuel.

Ironically the Luftwaffe had quite a few aircraft right to the end of the war. But for lack of fuel those aircraft became increasingly less effective. Germany would eventually lose no matter what but I think they would have been a much tougher nut to crack if Goering had built a few more Gelsenberg size hydrogenation plants during the late 1930s.


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## jim (Mar 19, 2012)

The Fw 190A -8/9 (the ones to be compared with Mw 50 Bf109s) had many positive things as Mr GreqP wrote. However by 1944 was not any more great airsuperiority fighter.Too much weight and no additional power. Bf 109G14, G10, K4 totaly outperformed it at all heights. 109s had better power loading, better wing loading, less drug. In my opinion even Dora was inferior performance wise to K-4 and G-10. 
Tank himself admitted that fw always needed more power than messer to be competitive because of his desicion to be very solid, easy to maintain, and strong for bad airfields operation.On theory that sounds good but as germany ,due to the lack of raw materials ,could not field powerful enouph engines Fw soon was in trouble. The terrorist of 1942 was desperately fighting for survival in 44. Numbers are desapointing. Even using 2000ps for boosted bmw 801,powerloading is mediocre.Above 20000ft it fall further. Wing loading is even worse. Whats the benefit of haevy armament if you can not use it? Or high speed agility if you are in trouble reaching high speeds?
In my opinion Fw190 airframe was far to heavy for its size. At 4400kgr normal take off weight A-8 was heavier than fighters with much biger wings. 
Bmw 801 was never totaly reliable,always a bad altitude performer, and druggy.Fw 190A9 on 2100 ps reached only 590kmh/h at 0m , La7 claimed 615kml/h on 1850 ps, 
On the other hand late 109s had better power loading even in comparison to f8f.


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## Denniss (Mar 19, 2012)

davebender said:


> *Internal fuel capacity.*
> 340 liters. Me-109G
> 535 liters. Fw-190A.


Try again with 400 liters for the Bf 109 and 525l for the Fw 190. The Bf 109C/DB had 340l, from the Bf 109E they had a 400l main tank.


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## Jenisch (Mar 19, 2012)

jim said:


> The Fw 190A -8/9 (the ones to be compared with Mw 50 Bf109s) had many positive things as Mr GreqP wrote. However by 1944 was not any more great airsuperiority fighter.Too much weight and no additional power. Bf 109G14, G10, K4 totaly outperformed it at all heights. 109s had better power loading, better wing loading, less drug. In my opinion even Dora was inferior performance wise to K-4 and G-10.
> Tank himself admitted that fw always needed more power than messer to be competitive because of his desicion to be very solid, easy to maintain, and strong for bad airfields operation.On theory that sounds good but as germany ,due to the lack of raw materials ,could not field powerful enouph engines Fw soon was in trouble. The terrorist of 1942 was desperately fighting for survival in 44. Numbers are desapointing. Even using 2000ps for boosted bmw 801,powerloading is mediocre.Above 20000ft it fall further. Wing loading is even worse. Whats the benefit of haevy armament if you can not use it? Or high speed agility if you are in trouble reaching high speeds?
> In my opinion Fw190 airframe was far to heavy for its size. At 4400kgr normal take off weight A-8 was heavier than fighters with much biger wings.
> Bmw 801 was never totaly reliable,always a bad altitude performer, and druggy.Fw 190A9 on 2100 ps reached only 590kmh/h at 0m , La7 claimed 615kml/h on 1850 ps,
> On the other hand late 109s had better power loading even in comparison to f8f.


 
That's why I said the Anton with the 2,400 engine would be the correct to compare. Anyone has estimatives of it's performance?


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## Erich (Mar 19, 2012)

seems pretty obvious which had the superior altitude performance and which had the better gun platform considering why several JG's not just Sturmstaffels had their Fw 190A-8's covered a 1000 ft higher by 109G-6/AS machines...........later G-14 AS.


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## Gaston (Mar 20, 2012)

A small dose of Me-109 vs FW-190A reality to supplement the comparison?

All those misconceptions are in line the current (abyssmal) state of the knowledge, with the notable exception of the more experienced combat pilots of the era whose practical opinion obviously don't count as much as engineering theory in our great "scientific" age...

Fortunately, I have figured out fully the flight physics behind these anomalies, as they apply to prop fighters only: A simple flight test will settle the issue... I'll bet I am going to have to pay for it...

Johnny Johnson obviously didn't think the Spitfire Mk V out-turned the FW-190A...: 

http://i275.photobucket.com/albums/jj284/gaston11_2008/jjohnsononfw1901.jpg

Quote: "I asked the Spitfire for all she had in the turn, but the enemy pilot hung behind me like a leech-*It could only be a question of time*..."

"Vertical Turn" here is vintage slang for "Vertical Bank Turn": If you want to blind yourself otherwise please do so...

And, unfortunately for what one might assume of his closing comments about the Mk IX, sustained turns was one of the few areas the Mk IX offered *no* help in turns over the Mk V...: This is an RAE evaluation of the Mk IX vs the Mk V:

"*At 15,000 feet there was little to choose between the two aircrafts* although the superior speed and climb of the Spitfire IX enabled it to break off its attack by climbing away and then attacking in a dive. This manoeuvre was assisted by the negative 'G' carburettor, as it was possible to change rapidly from climb to dive without the engine cutting. *At 30,000 feet there is still little to choose between the two aircraft in manoeurvrability*, but the superiority in speed and climb of the Spitfire IX becomes outstanding."

Hundreds of combat accounts of the Spitfire Mk IX show an aircraft exclusively used in vertical combat to a remarkable extent (especially compared to the obsessive and successful horizontal turner that was... The P-47D!), and, unlike the P-47D, the Spitfire strenuously avoided any prolonged turn contests (but might have had a very tight initial radius)... 

For good reasons, the P-47D was a feared turn fighter, as the Germans found out in their tests: Quote: "The P-47D (needle prop) out-turns our Bf-109G" Source: "On Special Missions: KG 200"


A few non-theoretical quotes from the now far away real world...:

A quote from Hurricane pilot John Weir (click on John Weir link): Page Not Found (HTTP 404) - Veterans Affairs Canada 

"A Hurricane was built like a truck, it took a hell of a lot to knock it down. It was very manoeuvrable, much more manoeuvrable than a Spit, so you could, we could usually outturn a Messerschmitt. They'd, if they tried to turn with us they'd usually flip, go in, at least dive and they couldn't. A Spit was a higher wing loading..."

"The Hurricane was more manoeuvrable than the Spit and, and the Spit was probably, we (Hurricane pilots) could turn one way tighter than the Germans could on a, on a, on a Messerschmitt, but the Focke Wulf could turn the same as we could and, they kept on catching up, you know."

Quote from an Oseau demise witness (Jagdwaffe, "Defence of the Reich 1944-45" Eric Forsyth, p.202): "Many times I told Oseau the FW-190A was better than the Bf-109G........ Each turn became tighter and his Bf-109 (Me-109G-6AS) lost speed, more so than his (P-51D) adversaries."

Osprey "Duel" #39 "La-5/7 vs FW-190", Eastern Front 1942-45:

P.69 "Enemy (FW-190A/F) pilots never fight on the vertical plane.---The Messerschmitt posessed a greater speed and better maneuverability in a vertical fight"

P.65 Vladimir Orekov: "An experienced Fw-190A pilot practically never fights in the vertical plane"

Weirner Steiz: "The 190 was a much better aircraft than the 109: You could curve it"

Reichlin assessment team report of Dec 10, 1941 (FW-190A-1 vs Me-109F): "In terms of maneuverability, it (FW-190A) completely outclassed the Me-109. The Focke-Wulf could out-turn and out-roll the Messerschmitt at any speed."

Russian 1943 book:

"Germans will position their fighters at different altitudes, especially when expecting to encounter our fighters. FW-190 will fly at 1,500-2,500 meters and Me-109G at 3,500-4,000 meters. They interact in the following manner:

FW-190 will attempt to close with our fighters hoping to get behind them and attack suddenly. If that maneuver is unsuccessful they will even attack head-on relying on their superb firepower. This will also break up our battle formations to allow Me-109Gs to attack our fighters as well. Me-109G will usually perform boom-n-zoom attacks using superior airspeed after their dive.

FW-190 will commit to the fight even if our battle formation is not broken, preferring left turning fights. There has been cases of such turning fights lasting quite a long time, with multiple planes from both sides involved in each engagement."

-Squadron Leader Alan Deere, (Osprey Spit MkV aces 1941-45, Ch. 3, p. 2: "Never had I seen the Hun stay and fight it out as these Focke-Wulf pilots were doing... In Me-109s the Hun tactic had always followed the same pattern- a quick pass and away, sound tactics against Spitfires and their SUPERIOR TURNING CIRCLE. Not so these 190 pilots: They were full of confidence... We lost 8 to their one that day..."

S/L J. B. Prendergast of 414 Squadron recorded in his Combat Report for 2 May 1945 (Mk XIV vs FW-190A): 

I observed two aircraft which presumably had just taken off the Wismar Airfield as they were at 800/1000 feet flying in a northerly direction and gaining height.-------The other E/A had crossed beneath me and was being attacked by my No. 2, F/O Fuller. I saw my No. 2’s burst hitting the water--------The E/A being attacked by my No. 2 did a steep orbit and my No. 2 being UNABLE TO OVERTAKE IT broke away."

Gray Stenborg, 23 September 1944 (Spitfire Mk XII): "On looking behind I saw a FW-190 coming up unto me. I went into a terribly steep turn to the left, but the FW-190 seemed quite able to stay behind me. He was firing at 150 yards-I thought "this was it"-when all of a sudden I saw an explosion near the cockpit of the FW-190, upon which it turned on its back."

Fw 190A-4 at the Soviet AF SRI

"They also noted the obvious Focke-Wulf advantages: excellent all-round view without object distortion, good HORIZONTAL handling in all speed ranges,"

A translated Russian article from "Red Fleet" describing Russian aerial tactics against the German FW-190, from Tactical and Technical Trends, No. 37, November 4, 1943. 


http://www.lonesentry.com/articles/t...bat-fw190.html

Quote: -"The speed of the FW-190 is slightly higher than that of the Messerschmitt; it also has more powerful armament and *is more maneuverable in horizontal flight*."

My favourite quote of all:

-"the FW-190 will *inevitably* offer turning battle at a minimum speed."

Love that "inevitably" 

-"Coming out of a dive, made from 1,500 meters (4,650 ft) and at an angle of 40 to 45 degrees, the FW-190 falls an extra 200 meters (620 ft)."

The above means it is not great for boom and zooming (shudder)...

-"Throughout the whole engagement with a FW-190, it is necessary to maintain the highest speed possible. The Lavochkin-5 will then have, when necessary, a good VERTICAL maneuver, and CONSEQUENTLY, the possibility of getting away from an enemy attack"

-"In fighting the FW-190 our La-5 should force the Germans to fight by using the vertical maneuver."

-"FW-190 pilots do not like to fight in vertical maneuvers."

I could go on, but is it not funny how they ALL say the exact same thing?

Gosh! The conventional wisdom could not actually be wrong now could it? After all, we are all much smarter today than they were back then: Scientific Proof: IQ tests averages have risen 3 points every decade since WWII...

So these first hand conclusions are all, you know... Delusional... And that they all agree exactly is just, you know... Coincidence... Real sad...

Gaston

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## GregP (Mar 20, 2012)

Gaston,

When the Fw 190A was introduced, it gave the British a shock, and the Spitfire Mk V was developed into a later model that gave the Fw 190A a nasty shock just a bit later. They traded back and forth for a few mods. This is all well documented. Your Johnnie Johnson link is from a Photobucket album with "Gaston" in the link URL! Get serious. That isn't a source, it is a Gaston article, written by Gaston.

We had a Spitife Mk V and a SPitfire Mk IX at the Planes of Fame for some time. The Mk IX was better at top speed and at altitude, while the Mk V could climb very slightly better. The turn was almost equal with the Mk V being slightly better by a hair at the same speed. Both could climb almost twice the rate of an Fw 190A model.

Your quote from the Hurricane pilot is an Error 404 for me - page not found. The Soviet translation does offer some praise for the Fw 190 (which it deserved), but also a some criticism, which you conveniently neglect in your post. Your next link after that is an Error 404, file not found.

Gaston, All pilots like the fighter they flew in combat ... because they flew it long enough to get to know it, it's strengths and weaknesses, and survived. So, they flew a Spitfire for years and an Fw 190 for one or two flights and prefer the Spitfire, naturally. Or flew the Fw 190 for years and then flew a captured Spitfire for one or two flights and prefer the Fw 190. Nothing surprising about that, is there?

You seem to want to take a few quotes and make a sweeping judgement. That is not the scientific method and not the way aircraft are evaluated. We can easily find a few quotes the other direction and "prove" the opposite. I know one guy who says the world really is flat. Is his quote any proof of reality?

The Fw 190A-3 had a wing loading at normal takeoff weight of 43.6 pounds per square foot (8580 pounds) and the Spitfire Mk V had a wing loaidng at normal takeoff weight of 28.0 pounds per square foot (6784 popunds normal takeoff). And you think the Fw 190A coudl out-turn the Spitfire? You really should talk with the people who flew them or go get a pilot's license and fly planes with similar wing loading. You are the only person I ever heard say that the Fw 190 could out-turn a Spitfire, and that includes real, live Fw 190 pilots giving talks at the museum alongside real, live Spitire pilots doing the same thing. That's like saying a Beechcraft Bonanza can out-turn a Cessna 172 (just about the same wing loading fraction). Ain't gonna' happen in the real world ... at least often. Sure, some people see their attacker and start a turn too late and get caught before they can change directions. Happened to both sides.

Does this have anything to do with your "thrust column" invention from another forum?


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## wuzak (Mar 20, 2012)

Is it not the case that after tactical trials of a captured Fw190 Spitfire pilots were encouraged to make encounters with Fw190s into turning fights and avoid diving and climbing (ie zoom climbs)?


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## Siegfried (Mar 20, 2012)

There are many 'aspects' to manouverabillity. Turning circle can be measured in radious or in degrees per second. The rapid roll rate and well harmonised controls meant the FW 190 had superior 'instantaneous' manouverabillity. 

It's also incorrect to characterise the BMW 801D2 engine as being poor at altitude, it wasn't. It functioned well to 20,000 to 25,000ft.


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## Jenisch (Mar 20, 2012)

Siegfried said:


> It's also incorrect to characterise the BMW 801D2 engine as being poor at altitude, it wasn't. It functioned well to 20,000 to 25,000ft.


 
Hans Lerch, in his biography Luftwaffe test pilot, claims that Allied types such as the Merlin Mustang and the Tempest were only matched in general by the Bf-109 G-10 and K, and the Dora.


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## Siegfried (Mar 20, 2012)

Jenisch said:


> Hans Lerch, in his biography Luftwaffe test pilot, claims that Allied types such as the Merlin Mustang and the Tempest were only matched in general by the Bf-109 G-10 and K, and the Dora.



At what time? Time and dates are the key. So are versions.

There essentially wasn't a P-51B in service till December 1943. Up untill then the FW 190 was outstanding: it could easily outrun a Spitifre IX at sea level, could match the Griffon Spitifre XII in speed yet outclimb it and out run it at altutude.


FW 190 A-5 Performance
And remember these are early FW 190s compared with advanced or late allied fighters opperating at bleeding edge boost settings.

My impression is that the Luftwaffe lagged around 6-9 months in engine development from early 1943 untill mid to late 1944 when it rapidly caught up. This can perhaps be attributed to fuel issues as much as anything else.


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## Jenisch (Mar 20, 2012)

Siegfried said:


> My impression is that the Luftwaffe lagged around 6-9 months in engine development from early 1943 untill mid to late 1944 when it rapidly caught up. This can perhaps be attributed to fuel issues as much as anything else.


 
Why fuel issues?


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## Juha (Mar 20, 2012)

Siegfried said:


> At what time? Time and dates are the key. So are versions.
> 
> There essentially wasn't a P-51B in service till December 1943. Up untill then the FW 190 was outstanding: it could easily outrun a Spitifre IX at sea level, could match the Griffon Spitifre XII in speed yet outclimb it and out run it at altutude.
> 
> ...



Not surprisingly you forgot to mention that Spit LF IX outclimbed 190A-5 with wide marking from SL upwards and at low down the low level Spit XII also outclimbed contemporary A-5. Also during the later part of 43 Spitfires at last got upper hand in combat against Jagdwaffe.

In engines I agree, DB605A let the early 109Gs down up to and incl G-6, only with G-6/AS, G-10 and G-14 (G-6 with MW50) Germans redress the balance. It wasn't only a fuel question, there were foaming of the oil (the main problem) and spark plug problems too.

Juha


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## Jenisch (Mar 20, 2012)

The P-47 also ouperformed the Fw 190 A at altitude.


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## Siegfried (Mar 20, 2012)

Jenisch said:


> The P-47 also ouperformed the Fw 190 A at altitude.



Only Above 22,000ft and below 10,000 it was much slower.


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## Siegfried (Mar 20, 2012)

Juha said:


> Not surprisingly you forgot to mention that Spit LF IX outclimbed 190A-5 with wide marking from SL upwards and at low down the low level Spit XII also outclimbed contemporary A-5. Also during the later part of 43 Spitfires at last got upper hand in combat against Jagdwaffe.
> 
> In engines I agree, DB605A let the early 109Gs down up to and incl G-6, only with G-6/AS, G-10 and G-14 (G-6 with MW50) Germans redress the balance. It wasn't only a fuel question, there were foaming of the oil (the main problem) and spark plug problems too.
> 
> Juha



Spitifre IX was only faster between 7000ft and 14000ft, it was then slower, but faster again above 22,000ft. Below 7000ft the Spitfire IX at 18psig was much slower. In climb rate the IX, but only on 18psig, was a significantly faster climber. However the FW 190 was about the same as the P-47, P-51A, P-38 iand Typhoon climbe at the same time period. It leaves the typhoon behined at about 16000ft. The Spitifre IX was an exceptionally fast climbing aircraft along with the Me 109.

22,000ft is the point at which the FW 190's performance begins of drop off, but below that it performs well, and at low altitudes it is often superior. The Spitifre XII (griffon) scraficed so much for its marginal advantage at low alttidue it was ineffective at even modest altitides. Later FW 190s had the critical altitude at around 25,000-27,000ft and so did much better than 22,000ft.

The stuggle for performance in the DB601 was mainly related to knock control, high octane fuel reduces stresses on pistons, reduces thermal load on the cylinder, allows greater boost, alleviates spark plug issues. Whatever the limitations of the DB601 these stresses would have been alleviated by higher grade fuel.

A new generation of FW 190A with more powerfull engines was comming out at the end of 1944.


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## jim (Mar 20, 2012)

Juha said:


> Not surprisingly you forgot to mention that Spit LF IX outclimbed 190A-5 with wide marking from SL upwards and at low down the low level Spit XII also outclimbed contemporary A-5. Also during the later part of 43 Spitfires at last got upper hand in combat against Jagdwaffe.
> 
> In engines I agree, DB605A let the early 109Gs down up to and incl G-6, only with G-6/AS, G-10 and G-14 (G-6 with MW50) Germans redress the balance. It wasn't only a fuel question, there were foaming of the oil (the main problem) and spark plug problems too.
> 
> Juha


 
Mr Juha
Alleis had the luxury to built specialized sub models to cover weaknesses of their standard fighters.
In later 43 Jagdwaffe was fighting Soviets in the east, and americans in the west . With american heavies taking the full attention of luftwaffe Spitfires had much better opportunities . Read the Jg26 mission profiles in late 43 and compare it with 1942.But i agree from late 43 Fw was less competitive.
Mr Siegfried
Bmw 801 altitude performance was inadequate , thats very clear from every witness and thas way Dora was born
Mr GreqP
Your statement that Spits V and IX had twice the RoC of Fw seems inaccurate according to my bibliografy

Fw 190A8/9 were not totaly obselete in 44/45. They had great rate of rall, good sustained rate of turn at middle speeds which became better with the wide blade propellers of late 44, decent but not great performance below 20000ft. A good pilot could use the strong points of the aircraft to survive. But it was clearly lacking speed in comparison to the competition and AT THE SAME TIME had very high wing loading. Thats not a good reciepe for an air superiority fighter. The simple one stage two speed supercharger was a further a disadvantage. Fw in 44 could not force or escape combat using speed. If had high energy entering a fight could use his ailerons to good effect. But when energy was lost what options a pilot could have against Spit XIV, Tempest, P51 ,? Run ,accelarate, climb,dive, turn? Bf 109K4 G10 (if properly built) could out climb, out accelarate,and run . Late Fws (A6/7/8/9,D9) were FAR too heavy
As for the pilots memories are very valuable but often controversial: Hartmann ,Obleser,Rosmann of Jg52 were avoiding dogfights prefering boom and zoom tactics, while Lipfert,Dutmann and others of the very same Jg52 were hard core dogfighters. Galland was complaining about the turning of 109 yet Marseille was turning with everything. There are alleid references that say Fw s more dangerous opponents over Europe yet Fredric Arnold of 71st FS over northern Africa describes the 109s as morre agressive and dangerous. German pilots were trained from the early stages of their carreers not to orizontally fight Spitfires yet when posted to operational units found with surprise that experienced pilots (eg W-F Galland,Erwin Leykaf) did engange in orizontal turning ,often succesfuly. So what conclusion can be made base only on pilots memories? Of course using numbers can also hide the truth ( as varius anlosaxons site do)


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## Jenisch (Mar 20, 2012)

Siegfried said:


> Only Above 22,000ft and below 10,000 it was much slower.



"Only"? The combat was usually from 25,000 to above!


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## Gaston (Mar 20, 2012)

GregP said:


> Gaston,
> 
> When the Fw 190A was introduced, it gave the British a shock, and the Spitfire Mk V was developed into a later model that gave the Fw 190A a nasty shock just a bit later. They traded back and forth for a few mods. This is all well documented. Your Johnnie Johnson link is from a Photobucket album with "Gaston" in the link URL! Get serious. That isn't a source, it is a Gaston article, written by Gaston.



? This is a post war Johnny Johnson press article I posted many times before... I don't think your accusation of fraud has anything to stand on just because I saved it to my photobucket account...



GregP said:


> We had a Spitife Mk V and a SPitfire Mk IX at the Planes of Fame for some time. The Mk IX was better at top speed and at altitude, while the Mk V could climb very slightly better. The turn was almost equal with the Mk V being slightly better by a hair at the same speed. Both could climb almost twice the rate of an Fw 190A model....



The Mk V being better by a hair is exactly what I would expect given they are said to be close: Despite a much larger power increase than wingloading increase, the Mk IX was said to be roughly equal in turn to a Mk V, however I would tend to givve the edge to the aircraft with the shorter nose...



GregP said:


> Your quote from the Hurricane pilot is an Error 404 for me - page not found.....



They do say they changed the adress in it: That is where it's from anyway, and the text is copy/paste unedited... You will note he says "The Spitfire has a heavier wingloading" which is his observed experience, but very far from the raw numbers... I'll go with this guy's experience of the issue rather than the theory... It helps I have a theory that accounts for the discrepancy...



GregP said:


> Gaston, All pilots like the fighter they flew in combat ... because they flew it long enough to get to know it, it's strengths and weaknesses, and survived......



Then why don't you look at the strength and weaknesses they actually mention?

The startling thing is that, aside from a few closely matched Tsagi numbers (which are ridiculous concerning the P-47 being at 27 seconds when the Germans themselves recognized the P-47D out-turned their Me-109Gs at 21 second) and *ONE* mention of the Me-109 out-turning the FW-190A in a captured La-5 evaluation (and another very high altitude evaluation at 27 000 ft. being irrelevant), there is virtually NOTHING in all of WWII accounts that actually states the Me-109 out-turned the FW-190A... 

Perhaps that bears being at least *noticed*? 



GregP said:


> The Fw 190A-3 had a wing loading at normal takeoff weight of 43.6 pounds per square foot (8580 pounds) and the Spitfire Mk V had a wing loaidng at normal takeoff weight of 28.0 pounds per square foot (6784 popunds normal takeoff). And you think the Fw 190A coudl out-turn the Spitfire? You really should talk with the people who flew them or go get a pilot's license and fly planes with similar wing loading. You are the only person I ever heard say that the Fw 190 could out-turn a Spitfire, and that includes real, live Fw 190 pilots giving talks at the museum alongside real, live Spitire pilots doing the same thing. That's like saying a Beechcraft Bonanza can out-turn a Cessna 172 (just about the same wing loading fraction). Ain't gonna' happen in the real world ... at least often. Sure, some people see their attacker and start a turn too late and get caught before they can change directions. Happened to both sides.
> 
> Does this have anything to do with your "thrust column" invention from another forum?



I no longer use the "column" notion since you quite rightly pointed out it was the void ahead of the blades that mattered...

Since you work at or are associated with "Planes of Fame", let me ask you this: Are any of the aircraft you have in the collection equipped with a *wing strain gauge*?

I am afraid, from what I found out so far, not many warbirds, if any, are equipped with a wing strain gauge, or else it would have been easier to realize there is something wrong with basic flight physics for these powerful nose-driven low-wing types: For instance, in horizontal turns (but *not* dive pull-outs), you would have found 3G horizontal turns at a lower power level cause less wing flexing than at a higher power level for the *same* 3G horizontal turn...

Remember that in WWII they apparently had no G meters, so they could not correlate what the wing strain gauge would tell them to a given level of Gs...

If you know where to find wing strain gauge data correlated with horizontal turns on WWII fighters, I would love to see what that data says when you vary the power levels...

I know damn well that with a hugely greater wingloading there is no way the FW-190A will out-turn a Spitfire Mk V, yet that *is* what is observable in combat, and there is nothing you can do about it: I have yet to see a *single* multiple turn combat showing otherwise...

If it is impossible for the FW-190A to out-turn the Spitfire Mk V with a higher wingloading, then there is something wrong in the way we assume the wingloading is tabulated in our formulas compared to what the real aircraft actually perceives: If you did the wing bending comparison with a wing strain gauge, you would find the FW-190A's wings are under *less* loading than the Spitfire's wings in actual turning flight...

The turn test with the wing strain gauge data at various power levels would be very easy to carry out with just *one* aircraft: In theory, a 3 G turn at full power or at 70% power makes *no* difference to the wingload as long as the turn's G load is the same: If a large difference showed up you would know the flight physics are wrong for these types of aircrafts (and I am pretty sure they are)...

If the flight physics are wrong for that (regarding the power level being irrelevant to wingloading), then you know they are wrong for other things: The FW-190A and Spitfire did not load their wings in the same way, and that relates to the source of the power and the leverages and shapes involved...

The problem with current assumptions is they assume the world works according to what our math tells it to do: It is the world telling the math what it is calculating, not the math telling the world what it is doing...

If you could get an in-flight wing strain gauge turning test done, you would know what I am talking about.

Gaston


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## GregP (Mar 20, 2012)

Hi Siegfried, 

Just getting back to the thread ... a lot of traffic today! Huh?

I think it is correct to say the BMW 801 was not a good performer at altitude becuase the European war was largely fought at 25,000 - 35,000 feet and the Fw 190 radial model performance started to decline at 20,000 feet and was pretty much gone by 25,000.

If you look at the archive of M. Williams, he has several Air Ministry technical reports on many aircraft. Among them is the Fw 190A-3 Technical Report #7908. In the report, the gross weight at takeoff is given as 8580 pounds with 203 square feet of wing area for a wing loading of 42.3 pounds per square foot. Net wing area is 177 square feet. Aspect ratio is 5.87. 

The air craft was flown at the 3-minute engine rating and they got 304 mph at sea level, 325 mph at 11,000 feet, 375 mph at 18,000 feet, and 351 mph at 25,000 feet. Full throttle height in M blower was 4,500 feet and full throttle height in S blower was 18,000 feet. Speeds are TAS.

Max climb rate in M blower was at 4,000 feet at 3050 feet per minute and in S blower at 17,500 feet at 3280 feet per minute in the 3-minute rating. The 30-minute rating climbs were 2760 and 2750 feet per minute respectively. Climb speeds started at about 130 mph and went up from there. At high altitude, max climb speed was above 260 mph, which was closing in on max speed as the aircraft went up (like in all WWII fighters).

Max boost was 4.5 psi at 2,450 rpm. 

Rate of climb starts to drop off rapidly at 17,500 feet. Sea level speed was 304 mph and rises to a max of 325 mph in M blower and tapers off until switching to S blower at about 11,000 feet at 330 mph or so. Speed build up tp 375 mph or so at 17,500 feet or so, where it tapers off rapidly. These speeds are at the 3-minute rating. In the 30-minute rating power, the max speed was down from 375 mph to about 355 mph at 17,500 feet. 

The heavy wing loading was mention, along with smooth, well-harmonized controls. This technical report is located at http://www.wwiiaircraftperformance.org/fw190/fw-190-rep234.pdf . Other reports say the same thing, which is exactly what I said. Performance was good but not spectacular and tended to fall off above 20,000 feet ... which goes a long way to explaing why a B-29 would have an easy time with the radial engine Fw 190A models ... as I said earlier above. All tey had to do was get high and fast and the Fw 190A-3 would ahve a very difficult time catching the B-29 since the speed was only avaialbe at a 3-minute power rating. Otherwise, the top speed was about 10 - 15 mph faster than a Mistubishi Zero, which could not catch a B-29 under most circumstances unless ideally positioned at exactly the right time.

Now this is only one report, but there are many otehrs that say about the same thing, not just this one, including reports from the Lufwtaffe.


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## GregP (Mar 20, 2012)

Hi Gaston,

Being an electrical engineer, I am very fmailiar with stain gages (not gauges). I used them as primary data acquisition for more than 10 years in my engineering career. They are simple and relaible. They are also not cheap to employ and, when used, are funded by a project under development with funding for dynamic load testing.

Our museum is a flying museum dedicated to preservation of WW2 (and other) milirtary warbirds in flying condition. We do not have any need to run strain tests since we certify, maintain, and fly to the published manufacturer's manual levels or less. That is, we fly within the operating envelope at all times and have a great safety record.

Let me put it to you this way. If you can afford the stain gages and assocauited electroncs, round up some, go get a friend with an RV-4/RV-6 to test it out for you. I already know what it will say, having flown g-meters in RC aircraft for several years and exploring level turns at verious degrees of bank. These RC planes had a higher power loading than ANY full-scale aircraft and could accelerate from zero to 150+ mph in less than 4 seconds/ I'm talking about a Quickie 500racer with a Nelson 40 up front. Top speed in the 190 mph range with wicked accelration, definitely higher acceleration than ANY jet aircraft. I got exactly what I ecxpected to get in my own tests, but feel free to eperiment. The g-meters in verious full-scale aerobatic aircraft I have flown say the same thing as I expect, too. You may find a G-meter is WAY less expensive, practially, than strain gages.

Actually, the strain gages are cheap. The associated instumentation amplifiers and other electronics as well as data recording systems are, while not expensive to an aerospace company in a developemnt effort, very expensive to ME, especially since I studied Physics and Aeronautics already, and so have little interest in re-proving what I already know. But, feel free to go for it. I suggest the friend with an RV as a very good starting place. Any competent RV pilot can do a 4.0 - 4.5 g loop or horizontal trun and you can record your data at various power settings. 4 g's is 4 g's. regardless of the power involved, and any vertical (pitch axis) 4-g acceleration (without rolling or yawing) will impart the same stress to the airframe. Any horizontal (yaw) 4 g stress will do the same, but it will be different from pitch stress. 

I don't believe I ever got to a 4 g stress in the roll axis and I don't know anyone esle who did either ... unless it is some unknown F-104 pilot who tried to find the maximum roll rate of the Starfighter. If he did that, he probably ejected from the flat spin and tumble after 6 or more rolls ... it diverges at max deflection and gets very unstable. I believe the emergency checklist for that action terminates in "EJECT!" 

Of course, about 75% of the F-104 emergency checklist terminates in "EJECT!" so that seems to be nothing unusual in the F-104.

Sorry Gaston, I don't believe your claims but, by all means, investigate on your own. If you are well instrumented, verified and have a current calibration, you'll get what everone else gets who has done aerodynamic testing. But, if you DO it, at least you'll have some fun doing it.


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## Milosh (Mar 20, 2012)

What is a stain gage/gauge?


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## Gaston (Mar 21, 2012)

Thanks for the details Greg,

Unfortunately the data I would want could not be from an aircraft of less than 1000 hp and 5000-6000 pounds, and would have to be a low-wing monoplane with a single piston nose-traction engine... I doubt the effect is scaleable to anything else, even to a high wing monoplane of the same weight/power...

My theory is based on the migration of the Center of Lift due to prop assymetry resistance, which substitutes to the elevator's effort so that there seems to be no effort involved for the pilot in defeating the prop's inside turn assymetry resistance. It would not be surprising if such an effect was not scaleable: It could be the prop's resistance to turn assymetry manifests itself in a non-linear way: Ie, none below a certain power level, and suddenly a lot above a certain power level...

What I would like to find is where is the actual data for WWII aircrafts? Wing strain gage data for jets is of course irrelevant.

You would think wing bending data would exist somewhere for WWII types of aircrafts...

I have little doubt that some wing strain data does exist, but is it correlated to horizontal turn Gs and power output in horizontal turns? Since apparently no one knows that this is a problem, I wonder if the data would have been laboriously collected and correlated in this way for a non-existent issue? Especially since, at the time competitive combat turns on prop aircrafts mattered, there was apparently no G meter to correlate the turn data to an amount of wing bending...

So if you have wing bending data for WWII figher aircrafts, I would certainly like to see it, or know where I can find it.

As for the notion that you "know" what is going on here, sorry: Every year I find a dozen or so new accounts to the thousands I have already gathered, and every time a "new" one arrives it points in the opposite direction to the conventional wisdom (how do you like the "new" RCAF account of John Weir?): Anyone who thinks the Me-109G out-turns in sustained low-speed turns the P-47D, or that the Spitfire (any mark) out-turns in sustained low-speed turns the FW-190A is more than out to lunch: If they had genuinely tried to be less informed, they would not have succeeded...

Regardless, if you could find that wing bending data, I would be most grateful...

Gaston


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## GregP (Mar 21, 2012)

First, a strain gage is a two-axis (shaped like a cross or an "X") piece of metal foil attached to a metal beam ... such as a wing spar. Each leg will slightly change resistance as it gets compressed or stretched in tension by bending of the beam (or wing). From this, the slight voltage differences from excitation can be amplified and the stress and starin can be calculated. It is basic materials science and is widely used in figuring stress and strain in aircraft structures.

Gaston, I sympathize with your need for a high horsepower, heavy aircraft to test. The museum will usually do this type of stuff ... but not for free. If you are willing to pay for it, it can probably be arranged. P-51 Mustangs go for about $1600 per hour or so and other planes are proportional to costs. A P-40 is less and a B-25 is probably in the neighborhood of $2,500 per hour or so.

The RV-6 can be flown for ... maybe ... $50 per hour, so I thought the cost differntial was worth the savings.

But, if not, then the only obstacle is money. For enough money, we'll repaint and fly any of our aircraft for films, etc. If you want to blow up a Merlin with full power runs, all you have to do is supply the replacement engine and we'll probabluy do it for the right price and the right to salvage the blown engine parts. The right price includes incentives for the museum and pilot's time and risk and well as any fees incurred for airspace reservation ... assuming the task is reasonable and both the museum and the pilot (and FAA) agree with that assessment.

So if you want to dive a P-47 vertically at full ppower for 20,000 feet from 35,000 feet, we have done that. It wasn't cheap for the party involved, but it was done. The results are known but are the property of the guy who paid for it. You could do the same if you want and you'd own the data along with the museum, if the contract reads that way. As far as I know, we ALWAYS have a right to data we produce or we don't produce it. But that could change with the money ...

Maybe the RV-6 is sounding better?

All I'm saying is that I don't know anybody who will instrument his warbird at his own expense and subject it to stress. They operate at book limits or less, and no owner wants to stress his aircraft beyond what is considered normal ... unless he has financial incentive to do that.

Good luck.

And any 28 lbs/sq ft aircaft will out-turn any 42 lbs/sq ft aircraft ... really. No bull. It's basic aerodynamics and assume broadly similar airfoils and moments, which ALL WWII fighers had. None were fielded with BAD airfoils and the single engine types had broadly similar moments of intertia about all axes (of course the twins were different from the singles). Without high-lift devices to overcome the basic wing loading difference (and the Fw 190 didn't have them) then the ligher wing loading fighter will out-turn the heavier wing loading fighter. That assumes competent design and both the Spitfire and the Fw 190 were very competent designs by two talented designers. Both aircraft were thoroughbreds and were very well designed, so there was none of the "idiot designer" stuff involved.

Sorry, the Fw 190A didn't out-turn a Spitfire V unless the Spit pilot didn't use his aircraft very well. I'm sure that happened, but not very often after the initial encounters. Until the avent of the Fw 190, the Spitfire pilots didn't have to extend their aircraft very hard in horizontal turn against the Me 109 (the 109's basically fought in teh vertical or they had problems with Spits). So, the early encounters with the Fw 190 were likely cases of lackluster response from the Spits due to not ever having to do anything else in the turn fight.

After a few shoot-downs, that changed really quickly and the Fw 190's were recognized and responses were altered accordingly. Look at combat record, say, after 2 months of Fw 190 vs. Spirfire combat and you won't find the Fw 190 out-turning the Spits since the Spit drivers were then aware of the threat and reacted accordingly.

Also, the Spitifre would EASILY outclimb a radial-powered Fw 190. Look at the power loading and the recorded rates of climb.

This isn't all that tough, Gaston, but we disagree here heavily. That isn't all that bad and I know I will not change your opinions. Likewise, mine are pretty solid and are rooted in real-life knowledge of real-life warbirds, including real-life radial-powered Fw 190's ... including Paul Allen's real-life, BMW 801-powered Fw 190. Our museum was involved in the test flying and the subsequent display flying from the first test flight to now. It is very good, but the Spitifres aren't in danger of being out-turned if the Spit driver is compentent and aware, then or now.

I'll look for the wing bending data in my free time as I am now intersted, but AFTER our May airshow in Chino. That is the full-time free-time occupation until after the first week in May. I'm working on one of our displays and helping with an engine change after overhaul.


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## Gaston (Mar 21, 2012)

Well I am very glad to hear you are directly involved with warbirds, and that almost anything can be done for a price!

I won't be able to pay such money for now, but in a few years down the road this is not inconceivable: There would be no excessive G strain involved for the airframe as I need no values higher than 3.5 Gs in a full near 90° bank. I might ask full "normal" power if that is possible: Maximum continuous power. If near WEP is possible for one turn, at a price, then so much the better! 

The main thing would be a variety of lower power levels at the same 3.5 G sustained turn rate... Right down to 50% power or whatever is possible at 3.5 Gs... The preferred aircraft would be the P-51 or later Merlin Spitfires, maybe even both!

Another interesting thing to test would be the use of full coarse prop pitch during slow speed turning on the P-51D: You remember the pilot account that made intricate references to this... At 20 000 ft. there should be enough room for safety...

I am surprised at how involved is the strain gage data gathering, as I would have thought it was a simple straight wire whose "shortening" under bending would be measured...

If it is more precise, then so much the better!

Since the P-51D is around 9000 lbs, and 3.5 Gs would be (in theory) 31 500 lbs on those wings, would it be possible to have a set of spare wings bent to 31 500 lbs to get a reference to the wing bending results in flight? I fear doing that to a flier would be unthinkable.... Are there spare P-51 wings around that could be used as a data reference point?

I am very glad I got you interested in finding wing bending data, as I am personally convinced that this could prove very valuable.

I'll await whatever you can come up with in your research!  

Gaston


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## wuzak (Mar 21, 2012)

I would imagine any WW2 wing bending data would be from static testing only.


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## wuzak (Mar 21, 2012)

GregP said:


> First, a strain gage is a two-axis (shaped like a cross or an "X") piece of metal foil attached to a metal beam ... such as a wing spar. Each leg will slightly change resistance as it gets compressed or stretched in tension by bending of the beam (or wing). From this, the slight voltage differences from excitation can be amplified and the stress and starin can be calculated. It is basic materials science and is widely used in figuring stress and strain in aircraft structures.



The actual strain gauge is a single axis device - but for most purposes using just a single axis isn't very useful. Often they will use two devices mounted at 90° (as you said), or 3 at 0°, 45° and 90°







As you can see from this picture, you need a channel for each strain gauge axis used.

btw, it's gauge pretty much everywhere except the USA.


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## Vincenzo (Mar 21, 2012)

is not full true that 190 can not outurn a Spitfire, the wing load is not all, at some speed 190 can turn best of Spitfire (i read this time ago and now i don't remember if comparison was for a Spit V or a IX maybe a V)


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## GregP (Mar 21, 2012)

Wayne, 

Yes there are single axis strain gages available; we never used them in a single-axis mode. We always used two-axis strain gage mounts, or even 3-directions, since the cost differential was slight (we already had the equipment available) and and the off-axis data was always required. In fact, I forgot that you can actually use a strain gage in a single-axis mode since we never did it except in training (to reduce training costs). When I say the insttrumentation amps are expensive, the term is relative. You can get good instrumentation amps from the vendors for $1500 and the strain gages themselves are cheap, on the order of $50 each. So a full X-Y set of amplifiers and strain gages, cables, oscilloscopes, etc. can be had for uinder $10,000 and sometimes for half that if the data are not complex.

That is a cheap test for, say, Boeing. For me personally, I am simply not interested enough to lay out thousands of dollars of my money to satisfy my curiosity. I already DID that at work many times, but not with aircraft wings. My work was with explosive devices and the stresses involved, particularly abiabatic pressure rise inside a closed bomb to measure the energy produced by 1 gram of propellant, deflagrant, or other explosive media. I leave aircraft tests to the aircraft designers and they pass along the costs to the buyers. Part of the cost of every Cessna or F-22 is testing cost.


Gaston,

Two things. 

First, spare P-51 wings are not available, but can be made. The spar is pretty simple and relatively low-cost compared with a complete wing. Fighter Rebuilders (Steve Hinton's business) can make you a complete P-51 wing spar, and can do it rather quickly. I think any bending data that are lying around for WWII fighters are static data from wartime research. Nobody destryos a P-51 today out of curiosity.

Two, I finally think I understand what you are trying to say when you talk of low-speed turn stress. See if I am right. You are thinking that if the aircraft is at a relatively low speed, say … 180 mph, and in a level, say … 4g turn, then the power in the engine must be increased and this, in turn, applies more stress to the airframe than a level, 4g turn at, say … 300 mph. Is that it? Also, the aileron on the downward-tending wing must be deflected more to keep at the correct bank angle, so the downward-tending wing incurs more stress than the upward-tending wing. Perhaps you are also thinking of maneuvering speed in a light aircraft, which is the maximum speed at which full and abrupt use of the controls is OK and will not overstress the aircraft.

Is that what you are trying to say?

First the structure of a fighter aircraft (or any aircraft, for that matter) is designed to be able to handle the stress of the aircraft sitting still on the runway witt the engine developing full power, or as close to it as possible, and the prop feathered, plus a safety factor of 1.5 or more; usually 2.0 or more. The reason the prop is feathered is that is one failure mode that should not cause airframe damage. After all, constant speed props DO fail.

Light aircraft have a placarded “maneuvering speed” which is not shown on the airspeed indicator, but IS a placard on the panel. In fighter aircraft, the maneuvering speed is commonly called the “corner velocity” or “corner speed,” and it the top left cusp of the V-N diagram. Below the corner speed, the aircraft will stall if the g-available is exceeded. Above the corner speed, the aircraft is limited by structural strength and can be made to fail in the air if overstressed.

Gaston, the wing of a WWII fighter will withstand a certain g-load plus a safety factor. If the aircraft is slow and if the ailerons must be deflected more to compensate, the g-load on that wing simply increases. Below corner speed, if the g-load available is exceeded, the wing stalls and the aircraft spins (or comes VERY close to spinning due to asymmetric loading at the stall). Above corner speed, the pilot CAN fail the wing, but above corner speed the aircraft is not in a “low speed turn” and the situation does not apply.

All that happens at lower speeds is that the stall margin is degraded a bit and the pilot must not stall it, particularly at low altitudes. Many Me 109’s and Fw 190’s stalled at low altitude when trying to turn with or escape from a Yak-3 or La-5 / 7. You can find tales of this in Russian writings by pilots of WWII. Lest you think that is anti-German, many Allied pilots also spun in at low altitude trying to evade the Messerschmitt or Fw 190. The real issue is the speed at which the evading fighter is flying relative to the V-N diagram when the pilot attempts an abrupt maneuver.

In simple terms. If the aircraft gets slower, there is less margin before stall occurs. As the aircraft goes up in height, the stall speed increases. At absolute ceiling, the stall speed is just above the maximum speed at which the aircraft can fly in straight and level flight. Any higher (or any load) and the aircraft stalls and descends. It has little to do with stress and everything to do with aerodynamics.

Recall tales of the "coffin corner" in a Lear 23? At 49,000 feet in a Lear 23, Mach buffet was 2-3 knots above cruise and stall was about 2-3 knots below cruise. Get sloppy and you get into either a stall or Mach tuck. It happened, sometimes fatally. By the tme the lear 25 was flying, the margins were 15 - 18 knots and there was no more issue.

A 747 at Mach 0.86 at 35,00 feet has a very comfortable margin from cruise to either Mach buffet or stall.


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## Shortround6 (Mar 21, 2012)

A big problem with trying to use anecdotally evidence as a "data base" is that some very big variables are not included.

By the time a fighter has been pulling a number of "G"s for more than a few seconds the pilot is greying out or blacking out. Turning at 4-6 "G"s is NOT a smooth steady turn. It is a succession of minor control inputs that tighten and loosen the turn that result in a 4-6"G" average. The more experienced the pilot the better he got at skating on the edge of blacking out, and relaxing pressure on the stick for a few seconds at a time to keep from blacking out. 
Another thing is that NO fighter could sustain a high "G" turn for very long without loosing speed. As the speed falls off the same "G" turn tightens in radius. 
Some planes had more control authority than others or, in other words, responded differently to the controls. Early Spitfires had overly sensitive elevators. It didn't take much to over control the plane and provoke a high speed stall. 
Now you have a low time pilot, trying to turn tight, with 4-5 Gs trying to pull his arms down into his lap and afraid of over controlling and Stalling, and he is graying out, getting tunnel vision and loosing situational awareness. A more experienced enemy ace out turns him with a theoretically inferior turning plane. Not exactly a big surprise or a reason to throw out decades of aerodynamic knowledge.


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## Juha (Mar 21, 2012)

jim said:


> Mr Juha
> Alleis had the luxury to built specialized sub models to cover weaknesses of their standard fighters.
> In later 43 Jagdwaffe was fighting Soviets in the east, and americans in the west . With american heavies taking the full attention of luftwaffe Spitfires had much better opportunities . Read the Jg26 mission profiles in late 43 and compare it with 1942.But i agree from late 43 Fw was less competitive...



Hello Jim
Now Spit LF IX wasn't pure low level fighter like LF V amd MK XII were, in fact it was faster than 190A-5 over 22000ft and PVO (Soviet Air Defence AF) used it as high altitude interceptor. British simply lowered the FTH for Merlin 66 to get its performance more suited for the combat enviroment of ETO. In fact LF IX became the standard Spitfire in ETO. We probably agreed that an extra difficulty for LW was that while in the East combats were fought mostly in low or medium altitudes in the West much of the combat were fought clearly higher up. Yes in 43 LW SE fighter performance was in stagnation but IMHO both 190 and 109 were still dangerous opponents. The technical superiority moved to and fro between Allied and Germans during the WWII.

Juha


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## davebender (Mar 21, 2012)

I think historical records will show that most WWII era aerial combat took place well below 25,000 feet.


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## Shortround6 (Mar 21, 2012)

You are right but for the Luftwaffe to ignore the 25,000 ft and up area of the sky would mean giving up any hope of controlling air combat in the West now matter how well they do in the East. 
Even the West much of the "combat" was below 25,000ft but the guys who could fly well at above 25,000ft often controlled the "Bounce" and thus the engagement as a whole. 

Designing equipment for "average" conditions can leave you very vulnerable to less than average conditions even without going to extreme conditions.


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## davebender (Mar 21, 2012)

The Luftwaffe page , Daimler-Benz DB 605
Isn't that what the DB605AS engine was for? 1,200 hp @ 8,000 meters. The DB605D was even better with 1,300 hp @ 8,000 meters. That provides a decent power to weight ratio for the lightweight Me-109G.


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## Shortround6 (Mar 21, 2012)

Yep, but it doesn't do much for the Fw 190 does it? which was a large part of this discussion. 

It also means it took the Germans until 1944 to equal what the Merlin 61 was offering in 1942.
1390hp at 7150 meters ,without ram. 
Max cruise of 990hp at 7700 meters compared to the DB 605 ASM 1040ps at 7100 meters.


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## davebender (Mar 21, 2012)

What difference does that make? Except for recon and pathfinders the RAF didn't normally fly above 20,000 feet. 1943 model P-47s weren't terribly impressive. 

The P-51B showed up about a month before the DB605AS engine. Perhaps that not a coincidence. The U.S. finally had a high performance bomber escort which Germany needed to counter with a high altitude version of the Me-109G.


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## Tante Ju (Mar 21, 2012)

Shortround6 said:


> It also means it took the Germans until 1944 to equal what the Merlin 61 was offering in 1942.



GM-1 - Wikipedia, the free encyclopedia


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## Shortround6 (Mar 21, 2012)

davebender said:


> What difference does that make? Except for recon and pathfinders the RAF didn't normally fly above 20,000 feet.



Try telling that to the Luftwaffe during the battle of Britain. Both sides were flying fighters at 25-28,000ft if not higher at times in order to get the bounce. The Luftwaffe knew that combat altitudes against the British were not going to go down. 
The American turbo-chargers were not a secret to anybody who had a subscription to any worth while aviation magazine of the 1930s. 
While fitting the Merlin XX to the Hurricane only boosted the speed at 25,000ft from 290mph to 313 it did change the rate of climb from 1260fpm to 1840fpm at 25,000ft and at 30,000ft the change was from 660fpm to 1120fpm. 
Figures for the 109E are a speed of 328mph and climbs of 1340fpm at 25K and 740fpm at 30K. Granted the 109F more than addressed the problem but the idea that British fighters would make no further progress in altitude performance seems pretty silly. Not having an engine in hand to counter a British change in tactics (wither they choose to fly at 25,000ft+ or not the aircraft could do it) seems a bit short sighted. It taking months if not a year or two to develop a major variant of an existing engine. It is certainly not done in weeks. 



davebender said:


> 1943 model P-47s weren't terribly impressive.



You might want to tell that one to the dozens of Luftwaffe pilots shot down those not terribly impressive P-47s. Even cutting the claims numbers to 1/3 leaves the P-47s shooting down Luftwaffe fighters at about 2:1 to 3:1.
And that is with the Americans gaining experience while the Luftwaffe has yet to reach the steep downward spiral of 1944/45.


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## GregP (Mar 21, 2012)

Lightweight Me 109G? Please!

The Me 109C weighed in about 5,065 popunds.

The Me 109D weighed in at about 5,345 pounds.

The Me 109E weighed in at about 5,519 pounds. See a trend here?

The Me 109F, widely regarded as the best of the breed by the Aces, weighed in at 6,054 pounds.

The Me 109G weighed in at about 6,942 pounds (normal, not max). Max was 7,053 pounds!

The Me 109K weighed in at about 6,832 pounds normal and 7,493 pounds max.

The Me 109G could outweigh the F model by a whopping 1,000 pounds, all without an increase in wing area. In truth, it was the heavyweight of Me 109's and had the heaviest wing loading.

Also, I said the performance of the radial-powered Fw 190's fell off about 20,000 feet and it does. I did not mention the Fw 190D or the Me 109 in performance fall-off above 20,000 feet, though the performance DOES fall off eventually, as it does for all WWII fighters. While the Me 109 COULD get high and fgast, it was unmaneuverable in the extreme when going fast ... but it could get there and fly intercepts on bombers effectively. I don't think any Me 109 pilot was eager to fight a Spitfire or Mustang at 28,000 feet. They were MUCH more likely to try to get the Allied fighters to descend and fight in the teens or LOW tewnties, where they were more maneuverable, than fight in the high twenties or higher. As I recall .. possibly wrongly, the Me 109G was at critical altitude for high blower at about 19,600 feet. Above that, the performance was still good, but falling off. That was with the DB 605 and was, I believe, the G-2. So the Me 109G pilot wanted to fight at about 19,600 feet (6,000 meters) if possible, where he had the best performance from his powerplpant.


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## Jenisch (Mar 22, 2012)

GregP said:


> While the Me 109 COULD get high and fgast, it was unmaneuverable in the extreme when going fast ...



I already read an interview with a Fw 190 pilot, were he told just this. He said to like more the 190 because it was "easy to maneuver". While the 109, you would need "muscles from a gigant" if wanted constant maneuvers.

The late 109s had servo tabs in the ailerons which at least diminished this disadvantage. However posterior Doras introduced hidraulically boosted ailerons.


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## GregP (Mar 22, 2012)

I have heard that before Jenisch, from actual Me 109 pilots, but thanks for the corroboration. They were astounded to sit in a P-51 and be able to see out as well as you can. After sitting in the P-51, they both said the Me 109 cockpit needed massive redesign for forward visibility.

The heavy controls (at speed) were the result of mechanical advantage, or lack thereof, and were correctable, as was the lack of rudder trim and aileron trim. Unbelievable, but true.

The Me 109, to me, was many good things combined with some bad things ... and ALL the bad things were fixable, but were never fixed!


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## Milosh (Mar 22, 2012)

Jenisch said:


> I already read an interview with a Fw 190 pilot, were he told just this. He said to like more the 190 because it was "easy to maneuver". While the 109, you would need "muscles from a gigant" if wanted constant maneuvers.
> 
> The late 109s had servo tabs in the ailerons which at least diminished this disadvantage. However posterior Doras introduced hidraulically boosted ailerons.



The rudder got a Flettner tab but the number of 109s with the tabs on the ailerons is questionable.


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## Tante Ju (Mar 22, 2012)

GregP said:


> The Me 109G could outweigh the F model by a whopping 1,000 pounds, all without an increase in wing area. In truth, it was the heavyweight of Me 109's and had the heaviest wing loading.



I think the K was the heaviest, which natural with all the bigger engines, cannons, MW boost, electric equipment etc. added. It weighted 3362 kg. Early G-1 weighted 3037 kg, F-4 2890 kg, F-1 2728 kg, E-3 2540 kg, the 109B around 2000 kg. All data from kurfurst site orginal papers. so there was not that much increase between late F and early G really. The G just gained the same weight as the others before. By far greatest increase was going from Jumo 109 to DB 109 because of the largest engine.

Besides increasing weight during a long used fighter is true for all WWII fighters. Allison Mustangs were much lighter than Merlin Mustangs, Griffon Spitfires were much heavier than Merlin Spitfires, late Yak 9 was much heavier than early Yak 9 etc. of course "all without increase in wing area", since it would be a major redesign. But that is important if there would be no increase in output of engine, since greater output engine can cancel more drag, allowing wing to use high angle of air flow and provide more lift.


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## GregP (Mar 22, 2012)

Hi Tanta Ju,

My post was in response to the "lightweight Me 109G" comments earlier.The fact that the Me 109 gained weight is not as important as how much it gained. Once the wing loading got past a certain point, perhaps some increase in size would have been better. In any case, the Me 109 was and is a great plane, ir ever there was one.


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## davebender (Mar 22, 2012)

> The fact that the Me 109 gained weight is not as important as how much it gained.


I disagree. 

What counts is power to weight ratio @ the most common combat altitude. Even that "overloaded" Me-109G6 had a good power to weight ratio compared to contemporary fighter aircraft.


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## Shortround6 (Mar 22, 2012)

Power to weight and wing loading are both important. Increasing the power to weight ratio increases certain aspects of performance but increasing wing loading can decrease others. It is not only turn radius, which can and was compensated for to some extent by tactics but field length, both take-off and landing and handling at low speeds. 
Increasing the power to weight ratio while the plane becomes harder for low time pilots to handle increases the accident rate. 
Getting back to turning, it is not just turn radius but the the higher speed at which a high speed stall occurs at high G's.
Higher weight also affects altitude performance. The higher weight requires a higher minimum speed just to stay in the air, which requires some of the extra power.


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## Gaston (Mar 22, 2012)

To comment first on what another poster added: The correlation between wing bending loads and slow speed turning at various power levels was likely never done on WWII fighter aircrafts. As he points out: *all WWII fighters wing bending data is likely static in nature*... 




GregP said:


> Two, I finally think I understand what you are trying to say when you talk of low-speed turn stress. See if I am right. You are thinking that if the aircraft is at a relatively low speed, say … 180 mph, and in a level, say … 4g turn, then the power in the engine must be increased and this, in turn, applies more stress to the airframe than a level, 4g turn at, say … 300 mph. Is that it? .



Yes that is exactly it: I'll go back to the power level issue just below... 

To bridge the gigantic gap in wingloading between the Spitfire and the FW-190A, and to still give a significant sustained low-speed turn advantage to the FW-190A, I figure the Spitfire's wing at a 3G turn at full power is *really* being bent as if it was almost at a "theoretical" 6G in actual in-flight wing bending force, while the FW-190A's wing at the same 3 G would be bent as if it was at say 4G: The gap between the 4G bending stress on the FW-190A wing (at 3G of "true" turn felt on the pilot) and the 6G bending stress on the Spitfire wing (also at 3G of "true" turn felt on the pilot) would overcome the Spitfire's theoretical wingloading advantage: In fact the Spitfire's wing *real in-flight wingloading seems higher than a FW-190A*, as RCAF pilot John Weir observed when he said "The Spitfire has a higher wingloading": It was observable experience to him, not theoretical numbers: I think those Spitfire wings are much more heavily stressed in low-G sustained turns than current flight physics theory considers, because there must be a loophole or error in basic flight physics that may not be scaleable to lesser power (or high-wing) prop aircrafts...

At 6Gs the Spitfire's wing would, according to this, be bent like if it was at 9G, but the airframe is rated around 12-14Gs so there is room in there for the effect... 

The root of the phenomenon (that I presume to exist) is something I call now the "CL collapse", but is in fact a CL displacement down and forward of CG as the elevator tries to raise the nose. 

This displacement is caused by the prop's resistance to be forced below its potential forward speed in an assymetrical way (which prop "resistance" insures continuing directional stability, even with the CL suddenly displaced forward of CG). 

A valuable counter-argument to that is that common drag, like a simple external mirror, also puts the whole prop surface below its potential forward speed, but linearly, and thus to my mind in a benign way: My argument is that the real prop resistance starts only with the assymetrical necessity of a turn. In other words the prop doesn't react strongly to being slowed down as long as it is done evenly on its whole surface, but leverage-wise there is hell to pay if you want to slow it down unevenly, as in a turn, because the length of the aircraft's nose suddenly intrudes, with leverage, as soon as any tilt to the trajectory is introduced... 

If tail and nose are close in lenght, as in a P-51, then the CL collapses *more* down and moves *less* forward. On a longer tail and shorter nose type, like a FW-190A, the CL collapse is *less* down but moves *more* forward: That is the engine of the system. It is largely an issue of how taxing for the CL is the leverage of the tail vs the nose: A long tail with a short nose is less taxing to the CL: The CL will go less down but strangely enough it will consequently want to move more forward, giving the CL more leverage to lift the nose as the turn increases the CL's lift.

CL collapse is a very small, perhaps micro-second event. The "pivot axis" of the CL collapse I situate in the prop face: It "sets" everything that follows: The more the CL collapses, the lower the prop's "pivot point" for that collapse, the lower the prop's "pivot point", the larger the prop surface brought below its forward speed potential: The larger the prop surface brought below its forward speed potential, the greater the disparity in incoming air speed between the outside turn of that area and the inside turn of that area. The larger that disparity in incoming airspeed, the greater the amount of thrust slanting for 1° of "normal" pilot-induced AoA increase.

In effect, for a micro-second the prop is "pulled" back assymetrically from the top as the CL collapses a very minor amount, then the prop rises as it rotates up, as the now forward CL *relieves the pilot of the effort of lifting it in an upward movement*, as the turn actually begins to tighten... There is a "scissor" action, with the CL being now forward of the CG, that is favourable to lifting the nose as the turn tightens (unlike if the CL had not moved forward of the CG). 

This is why huge prop forces at the nose *cannot be felt by the pilot in the elevators*: The collapsed CL moved *forward* and its action took over like a pulley, still responding to the pilot's touch but nullifying 90-99% of the effort to lift the nose, and thus lightening the load just like a pulley does.

Say the pivot point of the CL "collapse" is set in the lowest 10% of the prop, then 90% of the prop moves back compared to the trajectory: This may be equivalent to +0.9° of thrust slanting for each 1° of "pilot induced" AoA increase: 1.9° worth of *lift* for 1° AoA, 13.3° for 7° AoA, but probably after that no more than 20.6° for 14° AoA.

There must be an extra cost in drag in all that extra "added" thrust slanting angle, but if the rule is the same for all, how do you know there is an "anomaly"? 

So the "kind" of CL collapse ("deep" and "short" vs "shallow" and "long") sets the "boost" to the AoA by lowering the initial pivot point in the prop's face (which pivot point may exist for barely a micro-second to "set-up" what follows), and it also sets the amount of extra void above the wing needed to actually bend the wings beyond what the "visible" AoA could in theory accomplish.

Now I have to say I don't know how that extra void above the wing balances itself with the thrust slanting, as the AoA is gradually increased or decreased by the pilot, and even how it remains in place: How can that extra void (initiated by the CL collapse) not be washed away by the airflow? 

The only explanation I can come up with is that as the aircraft turns, the difference in the speed of the air above and below the wing is exacerbated, and some of that faster air below the wing "leaks" around the trailing edge as the CL collapses, this faster airflow moving then forward(!) and under the boundary layer on top of the wing, keeping the boundary layer higher and thus the void above the wing proportional to the "boosted" value of the AoA + thrust slanting. 

The proportional aspects would be as such: A tighter turn would make a greater air speed disparity on the top and bottom of the wing, "leaking" comparatively faster air from below the trailing edge, and lifting the boundary layer higher, creating a larger void. A slower turn would "leak" comparatively slower air and cause less lift of the boundary layer, for a lesser void.

That is a stretch, even for me, but if it has remained ignored for so long it cannot be that simple to figure out...

This is the only way I could figure how the engine's power could in fact increase or decrease the bending of the wing independantly of the turn's G force.

How many WWII types report faster *sustained* turn rates with seriously lowered power? The P-51D is most prominent, as is the FW-190A, with just one Me-109G pilot (Karhila) also mentionning the best sustained turn speed for the Me-109G-6 as being 160 mph with a strong emphasis on reducing the throttle to achieve this best sustained turn performance. 

Absolutely no mention of reduced throttle sustained turning for the P-47D and Spitfire, and relatively little for the Me-109: Why? I think the convenience of the flap "set up" plays a big role in how pilots will risk experimenting with lower throttle settings: The flap set-up for the P-47D must not have encouraged exploring lower speed turning performance at reduced power, and neither did the size and weight... The Me-109G could not really use its laborious flaps in combat, and the Spitfire had only full up or full down flap positions, a huge limitation in my view...



GregP said:


> Above corner speed, the pilot CAN fail the wing, but above corner speed the aircraft is not in a “low speed turn” and the situation does not apply..



The SETP "Society of Experimental Test Pilots" tested the corner speed of 4 WWII US types in 1989, at maximum continuous power ("normal power") and found the P-51D's "Corner Speed" in *horizontal turns* to be a surprisingly high 320 MPH, close to the maximum level speed at this power level at 10 000 ft for ALL four types: P-47, P-51D, F4U, F6F: This was due in my opinion to the loading of the prop in horizontal turns...

At War Emergency Power, the "Corner Speed" (minimum speed allowing 6Gs) in level turns would probably have been even higher: 350 mph?

Did you ever achieve 6 G in horizontal turns at full power below 300 mph? At normal power? Remember you cannot unload the prop by spiralling down: It has to be a true *level* turn.



Gaston


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## wuzak (Mar 22, 2012)

Gaston said:


> To bridge the gigantic gap in wingloading between the Spitfire and the FW-190A, and to still give a significant sustained low-speed turn advantage to the FW-190A, I figure the Spitfire's wing at a 3G turn at full power is *really* being bent as if it was almost at a "theoretical" 6G in actual in-flight wing bending force, while the FW-190A's wing at the same 3 G would be bent as if it was at say 4G: The gap between the 4G bending stress on the FW-190A wing (at 3G of "true" turn felt on the pilot) and the 6G bending stress on the Spitfire wing (also at 3G of "true" turn felt on the pilot) would overcome the Spitfire's theoretical wingloading advantage:



Do what?

Since wing loading is defined as mass divided by wing area, does the Spitfire gain mass in flight, or does its wing area reduce?




Gaston said:


> In fact the Spitfire's wing *real in-flight wingloading seems higher than a FW-190A*, as RCAF pilot John Weir observed when he said "The Spitfire has a higher wingloading": It was observable experience to him, not theoretical numbers: I think those Spitfire wings are much more heavily stressed in low-G sustained turns than current flight physics theory considers, because there must be a loophole or error in basic flight physics that may not be scaleable to lesser power (or high-wing) prop aircrafts...



Well, not sure what aircraft Mr Weir was comapring the Spitfire to - maybe he was saying its wingloading was greater than that of the Wright Flyer!


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## GregP (Mar 22, 2012)

I'll say one thing for you Gaston, you don't go in for short posts, do you? I'll have t read that one awhile ... 

By the way, at 8,000 pounds or less, the corner speed of a P-51D is very close to 265 mph and 8g. At 320 mph you can easily break a P-51D. If you exceed these limits, you may get away with it, but you have structurally compromised the aircraft. The desgn safety factor is 1.5, but the flight limits are the flight limits. Exceed them and you are a test pilot.

The Society of Experimental Test pilots does not have the authority to change the manufacturer's pilot manual. If they want to allow a higher speed, they have to do the engineering, the testing and verification, get approval and release the FAA-approved new flight limits. That has not happened and will not. The liability is WAY too high for anyone to be that stupid.

The guys running at Reno have increased the max speed with design work and streamlining (and that is allowed in the Experimental and Experimental Exhibition categories), but the structural limits are the same ... 8g at 8,000 pounds or less. Most of the P-51's running at Reno, including the National Champion, run at Reno at about 8,200 pounds, and their structrual limit is 7.8 g at 8,200 pounds. Even Strega, the current US National Champion has a pure stock P-51D structure underneath the streamlining and new cowling and small Formula 1 canopy. The engine may be putting out more than 3,000 HP, but the structure is stock P-51.

Jimmy Leeward's The Galloping Ghost taht crashed at Reno last year violated that and had a modified elevator trim system. He paid the ultimate price for that.

To get the g limit at other than 8,000 pounds, you divide 64,000 by the weight in pounds ... and that is straight from the pilot's manual.

You might not want to argue too hard about this one. Our museum operates two P-51D's, and I have been working the past month with the current Reno National Champion, Steven Hinton Jr, pilot of Strega, while we overhauled the left hand Allison from the Museum's P-38. We have discussed P-51's at length and Strega in particular. I think he knows the P-51's limits VERY well, and his structural numbers come right from the North American P-51 manual that was the wartime bible for the aircraft and still is. The numbers for Strega in particular come from the Tiger Destefani manual and are not public, but it is quite a bit faster than a stock P-51D. While the speed is faster, the structural limits remain the same and are calculated the same.


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## Shortround6 (Mar 22, 2012)

I am not sure why we have to throw out all the data that was collected with static testing. 

I mean those engineers/designers knew how much wing bend/deflection they were getting at certain given loading's. Any major discrepancies (like being off by 50%) would probably have been noticed. 

As far as "Did you ever achieve 6 G in horizontal turns at full power below 300 mph? At normal power? Remember you cannot unload the prop by spiralling down: It has to be a true level turn."

I don't think ANY WW II fighter was going to pull 6 "G"s in a horizontal turn for very long ( a couple of seconds?) without spiraling down. 

If you haven't seen them try these charts for starters. 

http://www.spitfireperformance.com/spit109turn.gif

Please note the Spitfire has to be doing 250mph in a 6 G turn or it stalls. also please note how far the Spitfire is from being able to maintain a 6 G turn. It has descend at rate equal to 27.5-28 degree descent in level flight in order to maintain the 6 G turn. 
Later Spitfires with more powerful engines will do better but then later Spitfires also weigh more and will have a a higher stalling speed limit which will affect the tightest turn radius. 
Please also note that turn radius varies with speed and G's pulled.

Which Spitfire is out turning which?

A. taking 19 seconds at a 1600ft radius at 375mph.
B. taking just under 16 seconds at a 1200ft radius at 325mph. 
C. taking 13 seconds at 800ft radius at 265 mph. 

All are pulling 6 Gs and all are loosing thousands of ft/min altitude. 

The Spitfires "best" turn performance seems to be a 23-23.5 second turn at 225mph at 1200ft radius at 3gs. it may actually hold height at that turn "rate" and speed.

Obviously starting position between two aircraft could be critical to a turning fight. a little altitude advantage helps, the pursuing airplane starting on the outside of the target plane has to pull more Gs ( or turn tighter, momentarily trading speed for turn radius)to get the target in the sights while starting from inside the turn (target turns across the pursuer) makes things easier for the pursuer. initial bank can affect results. 

Blacking out in a sustained 6 G turn can really affect the results


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## GregP (Mar 22, 2012)

Hi Shortround,

I agree and do not think ANY WWII fighter can complete a 6g level 360° turn. I seriously doubt a 4g level 360° turn since the power surplus is just not there to sustain it. Any 8+g encounters were momentary.

They CAN sustain 4 - 6 g if descending. Gravity works all the time, regardless of nationality.

We KNOW a P-51D can achieve 11-12 g at 495 mph without structural failure, but the survival rate is 50%.


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## GregP (Mar 23, 2012)

Gaston, first paragraph or so: how do you figure the Spirfire wing is bent at 6g in a 3g turn? How do you figure the Fw 190 wing is bent at 4 g in a 3 g turn?

The aircraft is pulling 3 g and the downward-tending wing may have less stall margin, but is still pulling 3g. The entire airframe is pulling the same g force, including the pilot. If he starts to feel a nibble on the stick (impending stall warning from air separating from the airfoil), he knows not to pull any harder or he will stall. Perhaps in certain circumstances, the stall might be preferable to the alternative course of action, but not close to the ground! That is certain death and most pilots would not pull to a stall deliberately at low altitude.

The wing isn't being "bent" by full power application; the structure can handle the engine torque and the wing doesn't experience any bending force from engine torque at all. The engine mount, longerons, firewall, bulkheads, and fuselage structure does, but it is designed to do that.

Gaston, aerodynamics is well known and the books explain it. You cannot reinvent a science that works according to the already-established rules. CL doesn't "collapse." 

Propellers don't have resistance to being forced below their potential speed. ALL propellers fly at speeds below their potential because there must be some angle of attack for lift to be developed from most propeller airfoils. I don't know of any symmetrtic propellers. Do you?

Coefficient of Lift is a number, not a force. It cannot be ahead of or behind the CG. There is a CG and center of pressure or center of lift, if you prefer the term. In a stable aircraft (and all WWII fighrter were stable) the center of lift is behind the center of gravity and the horizontal tail must "lift" downward to keep the aircraft in stable flight. If you lose the horizontal tail in a conventional wing-first and tail-behind aircaft, it will nose down very quickly. If you lose speed the tail loses lift faster than the wing ansd the nose drops. If you gain speed the tail gains lift faster than the wing and you nose up. Both tendencies return the aircraft to trimmed speed ... and it is called a "stable" aircrtaft. Lack of these characteristics makes for an unstable aircraft. Some unstable aircrtaft can fly for a short time, but not many, and the pilot must apply reverse stick force to make things work out ... so it sometimes happens that an aircraft that is unstable (loaded too far aft CG) can make it around the pattern and land. Most crash in a heap.

I'm afraid you need to read an aerodynamics text before you continue with theories that, while being inventive, are incorrect. But you have heard this before in another forum and obviously haven't yet bought an aerodynamics text. You also said in the other forum you'd post the math behind your theories within a month and that was more than 2 years ago with no math post to date. I am not trying to put you down, but aerodynamics is pretty well known, especially in here, and you are trying to say it is wrong while a century of real, live aircraft say that you may be mistaken since they mostly perform as designed.

Seriously, go take a course in aerodynamics. You'll like it.


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## Siegfried (Mar 23, 2012)

GregP said:


> Lightweight Me 109G? Please!
> 
> The Me 109F, widely regarded as the best of the breed by the Aces, weighed in at 6,054 pounds.
> 
> ...



I think you will find that the weight given for the Me 109G is with the twin Gondala weapons mounted. These added considerable weight. Unfortunatly this retrofit variants keeps cropping up as representative of its speed, climb etc.


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## Siegfried (Mar 23, 2012)

wuzak said:


> The actual strain gauge is a single axis device - but for most purposes using just a single axis isn't very useful. Often they will use two devices mounted at 90° (as you said), or 3 at 0°, 45° and 90°
> 
> 
> 
> ...



This particular kind of strain gauge in which the resistor is an etched device on a plastic film that is glued to the surface whose strain is to be measured was not available during WW2. Strain guages did however exist: they used taught wires, somewhat like a piano string, to act as the resistor.


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## GregP (Mar 23, 2012)

That may or may not be the case Siegfried, and I won't argue the point, but in many interviews with German pilots after the war, the weight gain in the Me 109G was remarked upon negatively. The people who did not like the G included Erich Harttmann. He stated that the F was the best Me 109 and the G was not nearly so good. It has been said the G model was heavy enough that it required almost full power in the landing configuration around the pattern. I have seen that said in books by William Green and in interviews of former Luftwaffe pilots.

All my references on German aircraft relect the weight gain, too.

Power to weight ratio affects climbing ability, wing loading reflects maneuverability, and span loadiong relects maneuverability at high altitude.

As far as I can tell by reading and talking with people who flew and fly them, the Me 109G was a strong climber that was much less maneuverable than the Spitifre counterparts. The thing is, the Spitifre was one of the best climbing aircrtaft of WWII in several marks. It lacked a bit in roll, but the LF Spits had clipped wings to assist in roll that made them less desirable at altitude. So the Me 109 fought well in the vertical arean. So did the Spitfire, but the Spitifre also was a strong turner.

Alas, everything is a compromise. Help in one area causes degradation in another area.

I will not select a "better" aircraft, I will jst say that the Me 109G was past the prime of the Me 109 series, at least in my book.

Last, in my time as an engineering manager, we used strain gages that were already laid out in two and three axes. The only time we used single axis units was when size dictated it. In those cases, we simply used multiple strain gages aligned to whatever axis was required. We used piezoelectric presure transducers for pressure in a closed explosive device and strain gages for stress and strain measurements on the structure.

Semiconductor strain gages weresd not available in WWII, but a kind of Wheatstome bridge arrangement with wire resistors was. What they mostly did was to static load the wings to the design load factor and then to the design safety factor. If the wing survived and returned to shape, it was assumed to be strong enough ... and it was.


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## Tante Ju (Mar 23, 2012)

I doubt Hartmann fly the 109F. It was not in service perhaps when Hartmann joined his unit.. Data show JG 52 completed switch to G-2 model by August 1942, a month or two after this plane appear, and no longer had any 109F. Hartman joined JG 52 in October, but intially flew transfer of Stukas.

IMHO G-2 was better than F in every respect. Probably best fighter 1942.


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## tomo pauk (Mar 23, 2012)

> Probably best fighter 1942.



As much as I like the Fs and early Gs, why would that be so? We can continue the discussion in the '1942: the best fighter thread', so this thread does not go off-topic


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## GregP (Mar 23, 2012)

Tante Ju, My remarks about Hartmann come from interviews WITH Hartmann. I make no claim he flew anything, but HE does. You may believe it or not, and you might be right wither way you choose.

I am not a fan of the Me 109G, but liked the E and F models. I am not a fan of the K models either, but late models of almost all piston fighters had poorer flying characteristics than earlier models, so the Me 109 is not singled out in this regard by any means. The Girffon-powered Spitfires don;t fly nearly as nicely as their lighter, Merlin-powered coutnerparts, either.

The exception is the late model P-47M, which was meavier and yet performed better in all aspects than earlier P-47's. Go figure, huh.


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## Gaston (Mar 24, 2012)

Shortround6 said:


> I am not sure why we have to throw out all the data that was collected with static testing.
> 
> I mean those engineers/designers knew how much wing bend/deflection they were getting at certain given loading's. Any major discrepancies (like being off by 50%) would probably have been noticed.
> 
> ...




All that data is entirely calculated and was not derived from actual flight tests. Think about it: If these calculations had proved of any practical combat value at all, would they not have been repeated for the Mk V, MXII, Mk IX, Mk XIV?

Besides, there is a chart for the Me-109E as well: If the British had access to more than one Me-109E they would have run out of spare parts to fly them long before they were halfway through flying half those innumerable data points... You have to read between the lines on things from that era...

Trust me, we don't have later war examples of those charts (I always see the same two: Spit I and Me-109E) because all that data proved completely useless, just as was useless the Mk I in 1944... That data would have been priceless to have and certainly would have been collected on similar charts for other types if it was of any value... The numbers data proved hard to gather consistently for some reason, and what we have later from the RAE are general recommendations... The same approximate mess is true for all other WWII fighters, as the testing procedures and instruments were simply not up to the task of informing us about these things if only on the most general terms, and sometimes not even that...

Want some further indication of that? The G data on those charts... There were apparently no G meters in 1940...

Gaston


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## GregP (Mar 24, 2012)

Gaston, I don't trust you at all .. but please continue.

You are in need of an aerodynamics course. The aircraft designed to conventional principles fly well. Amateur-designed aircaft sometimes don't. Think of the Christmas Bullet. 

You might want to have a good-flying aircraft (if you fly, that is) designed to formulas and principles that work. Then again, you ay be onto something. If so, build it, fly it, and post the results. We already know how Spitrfires, Fw 190's, etc. fly ... quite well. And when they pull 3g, they don't pull 6 g or 4g ... just the 3.


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## Gaston (Mar 24, 2012)

GregP said:


> I'll say one thing for you Gaston, you don't go in for short posts, do you? I'll have t read that one awhile ...
> 
> By the way, at 8,000 pounds or less, the corner speed of a P-51D is very close to 265 mph and 8g. At 320 mph you can easily break a P-51D. If you exceed these limits, you may get away with it, but you have structurally compromised the aircraft. The desgn safety factor is 1.5, but the flight limits are the flight limits. Exceed them and you are a test pilot..



12G matches the 1.5 safety factor you mention, as it does for most WWII types. 

I don't agree these aircrafts are easy to break in horizontal turns: They are easy to break in dive pull-outs, but hardly ever broke in horizontal turns in combat without some prior hits. At 320 mph you cannot break the P-51D in a *true horizontal* turn because, as the SETP tirelessly tells you through me, the P-51D can hardly even REACH 6G *horizontally* at that speed without stalling... Note they were allowed to stall the aircrafts for the test, but not to go for 7G... 

It is the *minimum* speed at which it can even barely *make* 6 G in a horizontal turns under normal maximum continuous power. At this power level or higher, when have you ever heard of a P-51D reaching 8 G at 265 mph in a *horizontal* turn? According to the SETP, "The P-51D at these speeds will still stall at the slightest provocation, dropping one wing violently"



GregP said:


> The Society of Experimental Test pilots does not have the authority to change the manufacturer's pilot manual. If they want to allow a higher speed, they have to do the engineering, the testing and verification, get approval and release the FAA-approved new flight limits. That has not happened and will not. The liability is WAY too high for anyone to be that stupid...



They tested to 6G only so as to not strain the P-51 and the 3 others: They could not even *reach* that 6G value *horizontally* below 320 mph without stalling it is what they are saying... I am sure they could reach it in pulling out of a dive at 250 mph, but that is NOT what they tested...



GregP said:


> To get the g limit at other than 8,000 pounds, you divide 64,000 by the weight in pounds ... and that is straight from the pilot's manual.
> 
> ...



But the manual doesn't care if you can't even *reach* those values in horizontal turns because you are stalling now does it?

Gaston


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## Gaston (Mar 24, 2012)

GregP said:


> Gaston, I don't trust you at all .. but please continue.
> 
> You are in need of an aerodynamics course. The aircraft designed to conventional principles fly well. Amateur-designed aircaft sometimes don't. Think of the Christmas Bullet.
> 
> You might want to have a good-flying aircraft (if you fly, that is) designed to formulas and principles that work. Then again, you ay be onto something. If so, build it, fly it, and post the results. We already know how Spitrfires, Fw 190's, etc. fly ... quite well. And when they pull 3g, they don't pull 6 g or 4g ... just the 3.



But how do you know that since we don't have the wing bending data while in flight?

How would you know if a wing determined to have 3G of lift in the wind tunnel at a certain point is not in fact reacting differently in the actual flight where the aircraft is not just a shape sitting in the wind?

The only way to really know is to know how badly it bends on the real thing.

You forget that aircrafts are not mathematical models: They are concrete objects made of matter, and matter tells the math what it is doing. 

Gaston


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## Gaston (Mar 24, 2012)

GregP said:


> Gaston, first paragraph or so: how do you figure the Spirfire wing is bent at 6g in a 3g turn? How do you figure the Fw 190 wing is bent at 4 g in a 3 g turn?
> 
> The aircraft is pulling 3 g and the downward-tending wing may have less stall margin, but is still pulling 3g. The entire airframe is pulling the same g force, including the pilot. If he starts to feel a nibble on the stick (impending stall warning from air separating from the airfoil), he knows not to pull any harder or he will stall. Perhaps in certain circumstances, the stall might be preferable to the alternative course of action, but not close to the ground! That is certain death and most pilots would not pull to a stall deliberately at low altitude.
> 
> ...



-How exactly do you know what the CL is doing? Any pictures of it staying put? 

-How do you know the wings are not working harder than the rest of the airframe? 

-How do you know there is not a greater void than expected over the wings on these types?

-Torque or P factor has nothing to do with anything here... 



GregP said:


> Propellers don't have resistance to being forced below their potential speed. ALL propellers fly at speeds below their potential because there must be some angle of attack for lift to be developed from most propeller airfoils. I don't know of any symmetrtic propellers. Do you?.



-Are you saying the prop disc surface is not symmetrical?

-How do you know pulling part of the prop disc back slower is not a lot harder than pulling it whole like an exterior mirror's drag does?




GregP said:


> Coefficient of Lift is a number, not a force. It cannot be ahead of or behind the CG. There is a CG and center of pressure or center of lift, if you prefer the term. In a stable aircraft (and all WWII fighrter were stable) the center of lift is behind the center of gravity and the horizontal tail must "lift" downward to keep the aircraft in stable flight. If you lose the horizontal tail in a conventional wing-first and tail-behind aircaft, it will nose down very quickly. If you lose speed the tail loses lift faster than the wing ansd the nose drops. If you gain speed the tail gains lift faster than the wing and you nose up. Both tendencies return the aircraft to trimmed speed ... and it is called a "stable" aircrtaft."



-I use CL for Center of Lift.

-I already explained why the CL can move in front of the CG without the aircraft becoming unstable: The resistance of the prop to assymetrical incoming air speed is what caused the CL to move in the first place: That resistance substitutes for the forward position of CG... 




GregP said:


> I'm afraid you need to read an aerodynamics text before you continue with theories that, while being inventive, are incorrect. But you have heard this before in another forum and obviously haven't yet bought an aerodynamics text. You also said in the other forum you'd post the math behind your theories within a month and that was more than 2 years ago with no math post to date. I am not trying to put you down, but aerodynamics is pretty well known, especially in here, and you are trying to say it is wrong while a century of real, live aircraft say that you may be mistaken since they mostly perform as designed.
> 
> Seriously, go take a course in aerodynamics. You'll like it.



-In historical terms a century is little, and instrumentation for testing the aircrafts in question was primitive when it mattered: That the mode of propulsion for combat suddenly changed explains why the error was never corrected, because the new mode flattered the old theoretical errors: You'll never need any of this to fly or even design a Cessna, and you can very well design a perfectly successful aircraft while still having your basic flight physics wrong...

Sorry, but if the flight physics say the P-47D is out-turned by a Me-109G in low-speed sustained turns, then the flight physics are dead wrong, because out of thousands of to-the-death combats I cannot find any indication of this happening or being even close to happening.

Same with the Spitfire vs FW-190A: Past an initial sharper Spitfire turn at the first merge (always from a dive, or high speed, or high altitude), sometimes gaining on up to close to one circle, the Spitfire is then hopeless if it lets speed get too slow: The opposite of what flight physics say...

On these types the basic flight physics is wrong, that's all there is to it: You can deduce most of the math from the bigger post I made on this thread, but in the end only in-flight wing bending measurements will prove me right or wrong...

Gaston


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## Juha (Mar 24, 2012)

Hello Gaston
test flown figures
Soviet tests were flown at 1000m. When time of turn is given xx – yy sec, they are different times for turning in left or right. 

Yak-9 (1943)
- 17 or 17 - 18 sec

Spitfire F Mk IX
- 17,5 sec

Spitfire LF Mk IX (Merlin 66)
- 18,5sec

Spitfire Mk VB 
- 18,8 sec 

La-5FN (1943)
- 18 – 19

Me 109F-4
- 19,6 ( sometimes 19,8 ) -20.5 NII (Soviet max speed for the ac on slow side, so probably the plane had some problems)

P-39Q-15, without gunpods.
- 20-21sec 

Me 109G-2
- >20-21,5 middle 21 NII (Finnish tests, also at 1000m, 1,3 ata, sustained 22 sec, speed 360 km/h 3G)

FW 190A-4
- 23-24s LII-NKAP
- 22-23s NII-VVS

Me 109G-2/R6
-22,6 sec

MiG-3 (1942)
- 23

P-47D-10-RE, engine R-2800-63
- 26 sec 30 sec depending on source.

Turn radius

Spitfire IXLF - 235m
Yak 1 - 275m
Yak 9? - 290m
La-5 : 310m
La-5FN : 295m
Me109G-2 : 290m
FW190A : 340m
P-39 : 253-280m


Juha


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## Shortround6 (Mar 24, 2012)

Gaston said:


> All that data is entirely calculated and was not derived from actual flight tests. Think about it: If these calculations had proved of any practical combat value at all, would they not have been repeated for the Mk V, MXII, Mk IX, Mk XIV?............
> 
> Want some further indication of that? The G data on those charts... There were apparently no G meters in 1940...
> 
> Gaston



So what if they are calculated. 

Your contention is that that the engineers and test pilots were off the mark by considerable amounts. 

I think that if the actual flight test results were as far off as you seem to think, somebody would have noticed. 

"G" meters in the instrument panel may not have existed in 1940. Recording "G" meters with a pencil drawing a graph on a drum of paper certainly did.

The NACA did a number of instrumented "G" tests of various aircraft by the late 30s including a few pylon racers. In fact back in 1922 the NACA had figured out how to Synchronize the following instruments. 

1) Single component gyro (N.A.C.A. Report #155).
2) Single component accelerometer (N.A.C.A. Reports #99 130).
3) Three component accelerometer (N.A.C.A. Technical Note 112).
(4) Air speed meter (N.A.C.A. Technical Note #64).
(5) Control force recorder (N.A.C.A. Report #112).
(6) Control position recorder (N.A.C.A. Technical Note #97).
(7) Multiple manometer (N.A.C.A. Report #148 ).

Since accelerometers are "G" meters it would seem that they did exist in 1940 and just perhaps those engineers/designers were not so ignorant of what was really happening as you think. 

SO in 1922 the NACA had the capability of recording the data from the above instruments and synchronizing the data to the split second. Something no test pilot could hope to do. 

Test report No.163 describes fitting an S.E.-5A with the the Three component accelerometer and gives graphs for the results in 6 different maneuvers. that is to say Instantaneous G load readings in 3 dimensions with the aircraft speed also recorded.

I would think that 18-27 years later they might have some idea if actual flight results differed from calculated values by a large amount and that since these reports were publish and freely available other countries had access to them and also had their own aeronautics research establishments performing similar work and publishing the results, at least until the very late 30s.


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## Shortround6 (Mar 24, 2012)

Gaston,

In some cases the wings were put in wind tunnels and the airflow studied at different angles of attack. At times there were strain gauges used to measure the lift or with several strain gauges you can measure the shift in the center of lift at different angles of attack and airspeeds. Many aircraft were flown with those little tufts of wool all over them to study airflow with cameras recording the movement. 

Of course your theory seems to be that a wing that will withstand being loaded with 10s of thousands of pounds of sand bags while static and a fuselage/wing joint that will withstand the torque of the engine just fine on the ground will, when flying behave like a slightly under cooked lasagna noodle. And nobody noticed this during the entire time high powered propeller aircraft were being built and flown.


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## GregP (Mar 24, 2012)

Gaston, Re post 70:

No, the manual doesn't care if you cannot reach the g-limit, The graph is the g-limit designed into the aircraft.

The air is not smooth most of the time. There are updrafts and downdrafts. The V-N diagram is the design limit for the weakest part of the aircraft structure, If you are flying in moderate turbulence, as you are many times over European mountains, and if you pull a 4g turn, horizontal ot not, it is entirely possible to see a momentary 5 - 6g depending on the turbulence level, perhaps more. That is usually called "gust loading."

Wartime P-51's most operated at anywhere frpm 9200 to 10500 pounds and were stressed per the formula I quoted at about 5.9 - 6.3g. Today, most Mustangs fly at 7,900 - 8,200 pounds and are stressed at close to 8g. 320 mph is a good speed in a P-51D but is not significant on the V-N diagram or anywhere else in the flight envelope. And Gaston, the limit at 8,000 pounds is 8g, not 8g plus a safety factor. The safety factor is there to get the pilot home after he screws up and over-g's the airframe. In some cases, WWII P-51D's came home with a few more degrees of dihedral than when they left due to over-g. The planes got home but werre scrapped for spare parts of a non-structural nature.

The saftey factor means the the planes can be overstressed and MAY still get you home. It is NOT intended as a safe operating limit.

I don't suppose this is all a big joke, is it?


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## Shortround6 (Mar 24, 2012)

The NACA instrumented a few pylon racers in the late 30s and found (using recording accelerometers =G meter) that a pylon racer executing a 10 sec 2 "G" turn could have momentary "G" loadings as high as 6 "G"s and, at times, in the negative "G" range. If you ease off the elevators to open the turn the "G" loading can go negative for a fraction of a second. The readings were taken during practice sessions and the planes were flying by themselves with no other planes around. Ground observers said the turns looked normal and smooth. 

A constant "G" turn is often a decreasing radius turn because as the speed bleeds off the "G" forces would lessen if it was a constant radius turn.


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## davparlr (Mar 24, 2012)

I don't even want to exercise the brain molecules!!!!


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## GregP (Mar 25, 2012)

Gaston, Re: Post 72:

You asked how I know some of these things. I took courses in aerodymanics including a wind tunnel! How do you think I knew it? Airplanes react to gust loads, but they perform as designed for the most part. The stresses are as calculated and demonstrated in testing.

For several years you have been advised to take a course in aerodynamics and get an aerodynamics text ... and you still haven't done it. I'm beginning to think maybe you DID try but were thrown out of class for interrupting the Professor in his or her lectures.

From this point forward, I will try not to react to the bait you post; please don't try to tell me it was really the Germans who bombed Pearl Harbor instead of the Japanese due to a "space-time continum collapse" due to the propeller resisting going slower than it t should be going ... if you do, I'll have another beer and laugh about it.


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## Gaston (Mar 25, 2012)

Juha said:


> Hello Gaston
> test flown figures
> Soviet tests were flown at 1000m. When time of turn is given xx – yy sec, they are different times for turning in left or right.
> 
> ...



Hello Juha,

Yes I know... And these tests led me astray for years as well, but consider their intrinsic value by the following results the German got actually flight-testing their own Me-109G against an underpowered P-47D Razorback with needle-tip prop: "The P-47D out-turns our Me-109G" (Source: "On Special Missions: KG 200"

So according to Soviet tests, German conclusions are that 26-30 sec < 20-22 Soviet/Finnish times?...

See the problem?

Now in order to evaluate who's right it helps to have a "background" of several thousands combat accounts to see where the reality leans to...

Out of 600 P-47D combat accounts at the Mike Williams "WWII Aircraft Performance" site, about 200 show multiple turns turning contests between P-47Ds and Me-109Gs...: P-47 Encounter Reports

Out of those roughly 200, ONE shows some parity with a Me-109G, in a fast steeply descending spiral to the RIGHT, over about 40+ 360s, then later against the same Me-109G, the P-47D slowly gains over the same amount of time in another downward spiral, winning the turning contest, but this time to the LEFT.

This is one of the few turning contests dated to late 1943, the vast majority being 1944. I think the better performance of the Me-109G could be due to it being a sleeker bumpless and retractable-tailwheel G-2 in 1943...

All the 199 or so other turning contests show a *crushing* P-47D superiority in all circumstances, especially down to 140 MPH, and even sometimes in climbing spirals (against gondola-equipped 109Gs I suppose)...

Usual turn gain success: Reversed tail position, or equal merge opposite-circle side start, in typically 3 X 360s°, about seven out of ten times...

The remaining 3 out of ten times, the P-47D gains into a firing position is LESS than 3 X 360s°... This in *all* types of flying situations, but better at low altitudes and slow speed for the P-47D, down to 140 mph!...

Number of Me-109Gs exhibiting even fleeting turn superiority: 0... Turn equality? 0.5 times in a high speed right-hand diving spiral.

The FW-190A usually out-turns the P-47D in sustained turns, sometimes very badly so in later 1944, less so in early 1944.

700 P-51D accounts: Two accounts of unsolvable parity with the Me-109G: 2 X 15 minutes or about 45 + consecutive 360s° to one side, on the deck. One other account of 90 + X 360°s: 30 minutes of continuous turning to one side, no victor... The P-51 usually wins turns vs Me-109G, but slowly: 5-10 turns is common.


So you can go with a bunch of numbers... Or the combat reality. 

Don't overestimate the smoke screen of pilot skill that is constantly thrown at you for the express purpose of clouding everything, so as to make even the most crystal clear empirical data useless... Unless you want to believe in the pilot's levitation powers...

My guess is that 22 seconds is not far off for the Me-109G-2 as per Finnish numbers, G-6 (and the P-51D) is more like 23-24 or even 26 with gondolas.

Tsagi tests have the Spit Mk V at 18.8 sec, and the Mk IX at 17.5, but note how Greg P has just told us the Mk V is slightly FASTER than the Mk IX in "Planes of Fame" comparisons... I think the real Mk V numbers are about 19-20 seconds and the Mk IX 21-22 seconds. The FW-190A was around 18-19 seconds, which makes it even with many Soviet fighters, just as combat accounts show. The P-47D was around 19-21 seconds, more towards 19 perhaps on the early Razorbacks and maybe slower than 21-22 on later Bubbletops: Similarly, some FW-190As were armored "Rammjagers" which would be slower as well.

Depending on the availability of intermediary flap settings (none on the Spitfire), reducing the throttle to below 200 MPH could shave as much as 2-4 seconds off all those figures, especially for the P-51D, Me-109G and the FW-190A : G-6: 19-20 secs, P-51D: 21 secs, FW-190A: 16-17 secs.

Ultimate turning speed for the Me-109G-6 was an extremely low 160 mph (250 km/h) according to Finnish ace Karhila:

virtualpilots.fi: 109myths

Which is why I give the 109G a "downthrottled" edge over the Merlin P-51, which it did not display at full power...

By the way you can do the math for my theory easily: Spitfires and P-51s may have a 30:1 prop-to-tail ratio: Assume a 900 lbs prop disc slice involved, so +27 000 lbs over the wingload at 3.5 Gs.

It could be as low as just a 20:1 ratio, but then it would be with a 1300 lbs slice of the prop disc, so still a similar +26 000 lbs as well...

FW-190A is probably as little as an 8:1 prop-to-tail ratio, with maybe a 600 lbs slice of the prop disc... So add + 4800 lbs to the wingload at 3.5 Gs... 

Now is the math clear?

The ratio of course uses the lever of the "crushed" forward position of the CL compared to the CG, say four inches, over a ten foot nose, hence 30:1...

BTW, I just learned the early "super-long" nosed early P-40 prototypes tended to pull their wings off, so much so a supply of wings had to be "borrowed" from a delivery to replace all those wings buckled by flight testing on those hugely long-nosed aircrafts.... Hmmmm, that couldn't be related to my theory now could it? 

Gaston


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## wuzak (Mar 25, 2012)

Greg, just looking at Juha's numbers for turns - both radius and time - I was wondering how important the turns are in air racing?

For example, how much time is spent in tsraight lines, and how much in the turns?

Could a plane that turns well but doesn't have a high top speed be competitive with a plane that turns poorly but has a high top speed?


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## wuzak (Mar 25, 2012)

Gaston said:


> Hello Juha,
> 
> Yes I know... And these tests led me astray for years as well, but consider their intrinsic value by the following results the German got actually flight-testing their own Me-109G against an underpowered P-47D Razorback with needle-tip prop: "The P-47D out-turns out Me-109G" (Source: "On Special Missions: KG 200"
> 
> ...



Aren't you just making up numbers?


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## Gaston (Mar 25, 2012)

Gosh, the likely closer-to-life figures are hard to hear about, are they not? 

The language is pretty clear for "my" turn figures unless your reading skills are seriously lacking... What else when Tsagi tells you 26-27 sec, is "less" than 20-22 sec.?

Oh yes, I know, the German testers are not as reliable as the Soviet testers... The Germans didn't know the P-47D as well as the Soviets did, and that's why it flew too well... 

Still waiting for *one* historical example of multiple consecutive level 360° turns gains, without a prior dive or high starting speed/altitude, by a Spitfire over the FW-190A... Please just *ONE*... *PLEASE!*   

Still waiting for *ONE* example of a Me-109G out-turning the P-47D in *any* circumstance...  

Your idea of these aircrafts is what they would call vapourware guys...

Gaston


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## wuzak (Mar 25, 2012)

Gaston said:


> Gosh, the likely closer-to-life figures are hard to hear about, are they not?



How are they likely?





Gaston said:


> The language is pretty clear for "my" turn figures unless your reading skills are seriously lacking... What else when Tsagi tells you 26-27 sec, is "less" than 20-22 sec.?



Do they? Or do they say that the Jug does take longer to turn than a Bf109?





Gaston said:


> Oh yes, I know, the German testers are not as reliable as the Soviet testers... The Germans didn't know the P-47D as well as the Soviets did, and that's why it flew too well...



What do British and American testers say?





Gaston said:


> Still waiting for *one* historical example of multiple consecutive level 360° turns gains, without a prior dive or high starting speed/altitude, by a Spitfire over the FW-190A... Please just *ONE*... *PLEASE!*



Did any pilot actually fly cosecutive 360° turns in combat?

Maybe there aren't reports of Spitfire pilots out turning their Fw190 counterparts because the latter were expressly instructed to avoid turning fights with Spitfires?

I know, from Eric Brown's book on Luftwaffe planes, that after the tests of the captured Fw190 by the A&AEE (or was it the RAE?) Spitfire V pilots were instructed to not follow Fw190s into dives and zoom climbs, but to try to force a turning fight.



To my mind combat reports by pilots cannot be considered a good primary source for aircraft performance. For one thing there is likely to be some exaggeration and some misremembering, and there is no guarantee that either aircraft involved was flown anywhere near its potential. You could have experten up against novices, one of the aircrfat may have already been damaged by previous encounters and so on.

The reason that the Tsagi and A&AEE/RAE and their German and American counterparts did tests was to evolve tactics to gain any advantages their aircraft had over the enemy.

btw I have never seen anyone descibe the P-47 as agile. Fast, powerful, tough, but never agile.


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## Juha (Mar 25, 2012)

Hello Gaston
a couple comments
combat reports are reports by the winners, loosers usually didn't write reports, especially those shot down over enemy territories. And because there are so few LW combat reports around we have little info from LW winners. I have read several memoirs of LW aces, but most of them are written by JG 52 aces, so not much use here and IIRC Knoke's memoirs isn't very reliable.

One must remember that the Soviet tests were flown at 1000m (3048ft) and most of Jug combats were fought at much higher level. Jug was designed for high altitude fighter but on the other hand 109G would also suffered less from its heavy control forces higher up.

What is interesting is that Soviet tests were in line Finnish tests and combat experiences. The only exception from that rule is LaGG-3 Series 28 which Finns thought was clearly poorer turner than the Soviet tests showed. Here the combats were as typical to Eastern Front mostly fought at fairly low level, so nearer to the circumstances in which the Soviet tests were flown.

In his 56th Fighter Group book pp. 21 and 23 Freeman writes on early 47Cs "As combats had taken place near same level as the bombers, many of the group's pilots had been forced into slow turning and climbing actions. It was clear that the P-47 was no match for the Bf 109 or Fw 190 in such circumstances..."

Juha


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## Shortround6 (Mar 25, 2012)

wuzak said:


> Greg, just looking at Juha's numbers for turns - both radius and time - I was wondering how important the turns are in air racing?
> 
> For example, how much time is spent in tsraight lines, and how much in the turns?
> 
> Could a plane that turns well but doesn't have a high top speed be competitive with a plane that turns poorly but has a high top speed?



The guy who ran the P-39 with the very short wings in the post war races later admitted that what ever he gained on the straight aways he lost in the turns. Top speed up but lap speed down or unchanged. 

I think the planes were only doing 2-3 Gs average in the turns back then. Prewar there was quite a argument over taking the pylons in a short, hard turn at higher "G"s to maximize the straight aways or using longer, larger radius turn at lower "G"s which slowed the plane less and let it accelerate back up to speed quicker. Of course pre-war many planes were still using fixed pitch props


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## Shortround6 (Mar 25, 2012)

Gaston said:


> BTW, I just learned the early "super-long" nosed early P-40 prototypes tended to pull their wings off, so much so a supply of wings had to be "borrowed" from a delivery to replace all those wings buckled by flight testing on those hugely long-nosed aircrafts.... Hmmmm, that couldn't be related to my theory now could it?
> 
> Gaston



Sure it could  or it could have to do with the fact that the P-36 wing was known to buckle anyway and had to be reinforced. XP-40 was the 10th production P-36 airframe. Stick heavier engine in airplane known to have a wing strength problem and pull the same "G"s and see what happens.


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## drgondog (Mar 25, 2012)

Gaston ...Yawn.


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## cimmex (Mar 25, 2012)

@drgondog
Why so arrogant? 
cimmex


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## GregP (Mar 25, 2012)

Hi Wuzak,

I have spent the last 3 weeks working with Steven Hinton Jr out at the shop. We are overhauling the left Allison from the Museum's P-38, 23 Skidoo. It is basically done. In that time, we talked about many things including Reno and Strega.

According to Steve, Some of the Reno turns are at 2 - 3 g and other turns are 5g - 6+g depending on your arrival line at the pylon. In the Valley of Speed, you are at 1.0 - 1.0g on the straightaway, but turn 8 is one of the hi-g turns. He tries to keep the g-forces as low as possible so as not to scrub off speed unnecessarily ... keeping it as smooth as possible. If he stays tight, the g-forces go up but the speed carried onto any subsequent straightaway or near-straightaway is lower, and that results in worse lap times. From this talk, I surmize that you need a fast plane that can also handle the turns ... but faster is probably more important than good turning. So, if you had a Burt Rutan, high aspect ratio racer (turns well) that was, say, 20 mph slower than Strega, I think Strega would win due to higher average speed around the course as a whole. The history of the race is filled with results from people who tried a new strategy ... but the facts are hard to dig out since the teams don't talk about it much, escpecially if they don't win or do better than the previous year.

Of course, all the Reno strategies may change now since they are relaying out the Reno course after Jimmy Leeward's accident last year. The new course has less of a turn at pylon 8, so as to have more of a straightaway near the pits and the the stands. None of the race pilots has ever flown this new course, so I suppose we'll get to see what it all means in about 5 months. The fastest 3 planes out there will be Strega, Rare Bear, and Voodoo, assuming they all show up ... unless someone else shows up with a dark hourse entry.

Rare Bear has the most horsepower on the ramp, the speeds for Bear, Strega, and Voodoo appear to be about the same, but Strega and Voodoo turn a bit better in theory. They also all race with wildly different strategies.

Rare Bear always starts the race slowly and builds up to fast laps as the race goes on. The R-3350 can DO that. On lap 1 or 2, the Rare Bear pilot won't be anywhere near race power. He is just making sure everything is in the green and is probably not at anything more than takeoff power. They take off at about stock power levels. By lap 4, he is probably at 80 - 90% race power.

The Merlins in both Strega and Voodoo are highly tuned and can produce very good power, but not for 8 laps; they get heat soaked and must be throttled back to live 8 laps. So Strega and Voodoo tend to throttle up and do the first 2 - 3 laps as fast and as smoothly as they can and then back off and depend on staying out in front while the people who can go fast all 8 laps try to catch up. Sometimes they DO catch up and sometimes they don't catch up. Rare Bear has Gold wins and so does Strega. Voodoo, with about the same potential as Strega, donesn't have a Gold Final win. It would have been a great race last year, but The Galloping Ghost had the accident on lap 3 on the first day of qualifying.

Since it was the first day of qualifying, Rare Bear wasn't really racing. They were just wringing out the Bear and going just fast enough to make the next round. If there is ONE truth at Reno it is this: You will never know who is the fastest until the Sunday Gold race becasue that is when they really go racing. The rest of the week, they go just fast enough to make it to the next race. Also, a Gold win gives the team bragging rights for only a year. Then they have to prove it all over again.

This year, Strega has some new drag reduction (I know what they did but it is not public information). That does not mean that the other planes also don't have some new drag reduction. Again, we'll see in September, won't we?

In the first unlimited heat race, the Sea Fury Race 232, the former September Pops, ate a piston and didn't fly again ... and still hasn't. It is sitting in a hangar at the Planes of Fame waiting for the R-3350 to be "freshened up." You can read that as overhauled since the piston that got eaten made a lot of metal in the engine.

I'm sure Flyboy J has some insights into the jet class, too. Maybe he'll post his thoughts in here? There are other posters out there who are Reno fans and have opinions, too. Maybe this needs a new thread?

Cheers, Wayne!


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## GregP (Mar 25, 2012)

Cimmex,

Our cohort, Gaston, likes trying to re-invent the science of aerodynamics in his spare time. He refuses to take a course in it, buy a book on it, or accept the explainations of people who have taken aerodynamics and have designed airplanes. His idea of proof of performance is a combat report written in the heat of emotion. War stories are fun to read but rarely tell the entire story. A guy who shoots down an ace that never saw him attacking isn't necessarily a better pilot; he surprised someone and probably got lucky. The ace that was just shot down never gets to file the combat report unless he lives and is repatriated with his unit. Even then he may not write it correctly, but may instead cite mechanical failure to avoid embarrassment. Running out of fuel is a better explanation for a combat loss than failure to spot your enemies.

Instead, Gaston comes up with some really inventive theories that, though inventive, are not related to the real world. After you have spent time tried to explain it to him a number of times, you tend to get frustrated and stop wasting your time with explanations that he discards in one-sentence dismissal while advancing another theory.

Guys like Drgondog have flown the warbirds, taken aerodynamics, and have gone on to design things that fly. After a certain number of failed attempts to disuade Gaston from unsound theories, the yawn may SEEM arrogant, but it is much more likely to be a case of, "we've been there before Gaston, and I won't go there again."


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## cimmex (Mar 25, 2012)

Thank you for the explanation. To be honest, I've never read Gaston’s posts completely because of the length.
regards
cimmex


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## davebender (Mar 25, 2012)

> Me 109, to me, was many good things combined with some bad things ... and ALL the bad things were fixable, but were never fixed!


The same can be said for a lot of wartime equipment. Without immediate wartime needs a lot of production decisions would have been different.

Not an aircraft but still one of my favorite production might have beens....
*Heuschrecke 10 10.5cm SP howitzer.*
Achtung Panzer! - Prototypes !






The Panzer IV was originally intended as an infantry support vehicle and this is what I think the Heer had in mind. 65 degree elevation allowed this vehicle to perform normal light howitzer fire support missions. 30mm frontal armor protection also allowed it to perform assault artillery missions. 200 were ordered during December 1941 and then cancelled. Until the Panther tank entered mass production Germany needed every available Panzer IV chassis to be completed as a tank.

If it had entered service it probably would have been the best 10.5cm SP howitzer in the world prior to the 1950s.


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## GregP (Mar 25, 2012)

Gaston, so help me you've done it yet again! Could you post a better explanation of a prop-to-tail ratio? And the math? Got me curious, you did.

I understand you are using the weight of the aircraft times the g-load for the "tail" part of it (which I think of as the lift produced by the wing ... how is that related to the tail?), but what in the world is a 900-pound prop disc? Are you weighing the propeller and comparing that to the g-force supported by the wing? Are you adding up the weight of air in the propeller-to-air interface arc? Are you assuming it to be gyroscopic precession force?

If you divide the weight of the propeller by the lift produced, what does that number indicate? Especially since the weight of the prop is included in the weight of the aircraft.

I am not trying to bait you. Just trying to understand prop-to-tail ratio. Never heard of that one before. I must have missed any earlier post on this one. The only tail ratio I am familiar with is when you are chasing women in bars as a yongster, and the research and test data on that one are probably beyond the scope of this forum. At least, that's what the rules in here say. The 3-views are interesting, though, particularly the armament.

Any 10,000 pound aircraft can generate 30,000 pounds of lift at 3g, but the ability to turn is much more related to the moment of intertia about the lateral axis ... the plane pitches around the wing's center of lift aligned wingtip to winftip. If the moment of intertia is relatively smaller, the plane pitches quicker thn another plane with a higher moment of inertia about the lateral axis. Of course, it is also related to the choice of airfoils for both the wing and horizontal tail, but I was assuming competent designers. By the above I mean a plane like a Polikarpov I-16, with the engine's center of mass very close to the center of lift, can pitch more quickly than a plane like the P-40, with the engine's center of mass farther from the center of lift. 

Of course, that assumes the designer intended to take advantage of the low polar moment of inertia in pitch and provided elevators relatively larger than the other designer did. If the elevators of the other plane are relatively larger and if the tail airfoil is chosen correctly, even a plane with a higher moment of inertia can out-pitch one with a lower number. All aircraft designes are compromises and some designers emphasize one particular characteristic above all others.

A great example is the Mitsubish A6M Zero. At its best corner speed, there was no other WWII fighter capable of pitching with it. I am speaking of modern monoplanes, and specifically not including obsolete biplanes.


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## tomo pauk (Mar 25, 2012)

davebender said:


> The same can be said for a lot of wartime equipment. Without immediate wartime needs a lot of production decisions would have been different.
> 
> Not an aircraft but still one of my favorite production might have beens....
> *Heuschrecke 10 10.5cm SP howitzer.*
> ...



The platform for the vehicle from the picture is from Pz-III.


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## davebender (Mar 25, 2012)

I think the variant pictured uses the Geschuetzwagen III/IV chassis. The same chassis used by the Hummel SP 15cm howitzer (a wartime interim solution) and the Nashorn SP 8.8cm/71 AT gun (another wartime interim solution).

The Heuschrecke variant ordered into mass production during December 1941 was made by Krupp and built on a Panzer IV chassis. I suspect the ausf B version would have used the Geschuetzwagen III/IV chassis which was designed for this type use. But we will never know for sure as wartime production requirements derailed the entire Heuschrecke program. Instead Germany squeezed the 10.5cm light howitzer onto a dirt cheap Panzer II chassis as a a wartime interim solution.

Speaking of wartime solutions.....
Would the DB605A engine enter mass production during 1942, before technical glitches were fixed? During peacetime I think RLM would refuse to purchase the DB605A engine until it could reliably produce the advertised 1,475 hp.


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## jim (Mar 25, 2012)

Juha said:


> Hello Gaston
> a couple comments
> combat reports are reports by the winners, loosers usually didn't write reports, especially those shot down over enemy territories. And because there are so few LW combat reports around we have little info from LW winners. I have read several memoirs of LW aces, but most of them are written by JG 52 aces, so not much use here and IIRC Knoke's memoirs isn't very reliable.
> 
> ...


 
Mr Juha
There are memoiries from many German pilots. I am surpised you dont know them. Knocke? Ah yes, he is unreliable. Willie Rescke ? Of course unreliable and leir . Norbet Hanning? Herman Buchner? Hans Ekkehard Bob? Alfred Grislawski ?( dont tell me he was a jg 52 pilot!) ,quotes from dozens other, Rall,Krupinski,Bar,Buhligen,Schroer and dozens others( its pointles to report them all)?Just read Jg 26 war diary.it is full of them Unreliable too? ( Overclaimers without a doubt) Why you"forgot" them? BecauseThey do not fit your claims?
What is reliable? The stories of the winners about "tail fork devils" and "whispering deaths"? 
Lipferts (JG52) book says that he could outmanouver the P51 (without Mw50) all times he encountered it. Its report according to you is "of no use"?
Also according to you Finish air force knew the 109 better than the germans? Its tests were correct and the german unreliable? Was reliable the soviet tests that show their aircrafts massively superior but at the same time refuse to publish their airforce losses losses?

Also about the P47 outurning the 109. for the lates P47D s i calculated { wiki data) 284 kgr/m2 wing loading and 3,131 kgr/h power loading
An unboosted 109G6 had 196kgr/m2 wing loading and 2,13 kgr/hp power loading. Do these numbers justify the claim of P47 superior in turning given an equal energy status starting the fight? Wide blade propellers was helpful but enough? Later 109s had wide blade propellers too and more power. Fw 190 also had much better numbers than p47s
Mr Greg P
I respect,admire and i am jealous of your work with warbirds. However .You claim that according to your experience Spits V and IX had twice the climb rate of 190. Eric Brown in "Wing of the Lw" page 85 writes"In climbing ,little diference was found between the Fw190 and Spit IX up to 23000ft" Let me tell you i believe him. 
You have very high confidence that the german damaged and rebuilt german aircrafts you have in America , and operated within modern regulations by American pilots are perfectly tuned and indicative of combat performance of actual Lw aircraft. Maybe,just maybe, Lw knew something about THEIR AIRCRAFTS better than your -without a doubt- excellent team.


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## tomo pauk (Mar 25, 2012)

davebender said:


> I think the variant pictured uses the Geschuetzwagen III/IV chassis. The same chassis used by the Hummel SP 15cm howitzer (a wartime interim solution) and the Nashorn SP 8.8cm/71 AT gun (another wartime interim solution).
> 
> The Heuschrecke variant ordered into mass production during December 1941 was made by Krupp and built on a Panzer IV chassis. I suspect the ausf B version would have used the Geschuetzwagen III/IV chassis which was designed for this type use. But we will never know for sure as wartime production requirements derailed the entire Heuschrecke program. Instead Germany squeezed the 10.5cm light howitzer onto a dirt cheap Panzer II chassis as a a wartime interim solution.
> ...



The Geshutzwagen III/IV used 8 road wheels per side, unlike the Heuschrecke (6 per side); I'll try to find out the definitive answer about the exact chassis type for the later 

added: the Rheinmetal version of the H. used full length (8 road wheels per side) chassis, while the Krupp version used shortened Pz-IV chassis (6 road wheels per side). I was mistaken to say it was based on the Pz-III


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## Juha (Mar 25, 2012)

jim said:


> Mr Juha
> There are memoiries from many German pilots. I am surpised you dont know them. Knocke? Ah yes, he is unreliable. Willie Rescke ? Of course unreliable and leir . Norbet Hanning? Herman Buchner? Hans Ekkehard Bob? Alfred Grislawski ?( dont tell me he was a jg 52 pilot!) ,quotes from dozens other, Rall,Krupinski,Bar,Buhligen,Schroer and dozens others( its pointles to report them all)?Just read Jg 26 war diary.it is full of them Unreliable too? ( Overclaimers without a doubt) Why you"forgot" them? BecauseThey do not fit your claims?
> What is reliable? The stories of the winners about "tail fork devils" and "whispering deaths"?
> Lipferts (JG52) book says that he could outmanouver the P51 (without Mw50) all times he encountered it. Its report according to you is "of no use"?
> ...



Frankly Jim
what are you whining?
I haven't read Reschke's, Bob's or Hanning's books and I'm middle of Buchner's memoirs and Bergström's Grislawski Graf book, so still in Eastern Front period in both, so not much help to 109 190 vs Spit and P-47 problem. Same goes to Lipfert's memoirs, which IMHO is amongst the 4 best WWII fighter polot memoirs I have read. P-47s cut Rall's career in ETO very short, I'm not aware Bär's, Krupinski's or Buhligen's memoirs, sorry. Have read something on Schroer but cannot recall his opinions on Spit and P-47. Kaiser said that Spit V wasn't very dangerous to 109 pilots in NA but Spit IX was. I have 3 of Caldwell's JG 26 books.

Juha


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## Denniss (Mar 25, 2012)

tomo pauk said:


> The Geshutzwagen III/IV used 8 road wheels per side, unlike the Heuschrecke (6 per side); I'll try to find out the definitive answer about the exact chassis type for the later
> 
> added: the Rheinmetal version of the H. used full length (8 road wheels per side) chassis, while the Krupp version used shortened Pz-IV chassis (6 road wheels per side). I was mistaken to say it was based on the Pz-III


This is a very early version of 1942 obviously using a heavily modified tank chassis with different roadwheels and changes to the suspension. This is not the vehicle commonly referred to as Heuschrecke. That's a Heuschrecke: File:Aberdeen Tank-Museum-Heuschrecke-10.jpg - Wikimedia Commons


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## davebender (Mar 25, 2012)

As far as I'm aware the December 1941 version is the only version of the Heuschrecke ordered into mass production. If not for the war Germany would have procured at least 200. 

Procurement of any other Heuschrecke model is only speculation. Personally I have my doubts about the turret unloading crane making it past prototype. I think Heer artillery personnel would prefer additional armor protection over the weight of the crane.


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## wuzak (Mar 25, 2012)

jim said:


> Mr Juha
> There are memoiries from many German pilots. I am surpised you dont know them. Knocke? Ah yes, he is unreliable. Willie Rescke ? Of course unreliable and leir . Norbet Hanning? Herman Buchner? Hans Ekkehard Bob? Alfred Grislawski ?( dont tell me he was a jg 52 pilot!) ,quotes from dozens other, Rall,Krupinski,Bar,Buhligen,Schroer and dozens others( its pointles to report them all)?Just read Jg 26 war diary.it is full of them Unreliable too? ( Overclaimers without a doubt) Why you"forgot" them? BecauseThey do not fit your claims?
> What is reliable? The stories of the winners about "tail fork devils" and "whispering deaths"?
> Lipferts (JG52) book says that he could outmanouver the P51 (without Mw50) all times he encountered it. Its report according to you is "of no use"?
> Also according to you Finish air force knew the 109 better than the germans? Its tests were correct and the german unreliable? Was reliable the soviet tests that show their aircrafts massively superior but at the same time refuse to publish their airforce losses losses?



I think you've jumped on the wrong person here.

It is Gaston who is basing his thesis on combat reports - mainly from ww2performance.com, which I would guess are predominately allied reports.




jim said:


> Also about the P47 outurning the 109. for the lates P47D s i calculated { wiki data) 284 kgr/m2 wing loading and 3,131 kgr/h power loading
> An unboosted 109G6 had 196kgr/m2 wing loading and 2,13 kgr/hp power loading. Do these numbers justify the claim of P47 superior in turning given an equal energy status starting the fight? Wide blade propellers was helpful but enough? Later 109s had wide blade propellers too and more power. Fw 190 also had much better numbers than p47s



Again it is Gaston making the claim. 

Somehow he thinks that the P-47 can out turn P-51s and Bf109s, and he also believes that the Fw190 outturns the Spitfire.

I think Gaston even claims that German tests show that the P-47 out turns the Bf109. The rest of us are sceptical.

I think if you look at previous posts Juha's numbers do not agree with this at all.


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## GregP (Mar 25, 2012)

Hi Jim,

The reported rates of climb for the Fw 190 radial models is about 60% of the reported rates of climb for the Spitifre IX and XIV. In zoom climbs, I'd suspect the Fw 190 of holding its own or being slightly better. The same can be said for the P-47 ... it's zoom climb was as good as anything in teh war. Once past the built-up kinetic energy, though, sustained rate of climb takes over and the P-47 was what it was. It could outclimb any Fw 190 at high altitude, but not on the way up there.

I have nothing against German aircraft or pilots; they were amomng the best in the world. Pilots like Hartmann, Rall, and Barkhorn certainly prove that.

All sides overclaimed, and that was probably mostly not out of any intention to do so. More likely the errant claimer lost sight of his quarry when it was goling down, apparently out of control and / or smoking and going down. The pilot of the damaged plane may well have been "playing dead" to separate and escape. Still, I am not a fan of revisionism. The victory awards should be as awarded during the conflict; not as revised by armchair quarterbacks laster sifting through records. To me, Erich Hartmann was the master with 352 victories. Doesn't mean he would not have done as well or better in another mount. All it means is he had the good fortune, good strategy and good planning / tactics to be in position to take advantage of his sklills repeatedly and not get caught unaware too many times. he was lucky to live through the times he DID get caught unaware.

I have seen rates of climb for the Me 109 F, G, and K up in the 4,000 - 4.500 feet per minute range and have no doubt they could climb strongly. I have NOT seen anything like such high claimed climb rates for the Fw 190. Mostly the radial engine version is quoted as in the 2,500 - 3,400 feet per minute range, and most Spitfiress after the Mk I were better than that rate by a nice margin. I even have a book on the Fw 190 written by a German that doesn't make claims of ultra-high rartes of climb for the Fw 190, especially the radial-powered versions.

I would not be surprised to hear the Fw 190 could fight quite effectively at 25,000 - 30,000 feet; I expect it could ... but the P-47D-25-RE and later were at home at 43,000 feet where the radial-powered Fw 190's could not even hope to get to, much less conduct a fight. Now I don't claim the P-47 was a better fighter than the Fw 190. Indeed, the Fw 190 ranks among the top 5 in almost anybody's book. What I claim is that the German planes, while good, were not greatly superior nor greatly inferior to Allied planes of the same general timeframe. That is, the German fighters, British fighters, and American fighters in the ETO were well matched, with possiby the experience going to the German experts, especially at first, but who were in serious decline after mid-1943 or so. Mostly, both sides had good aircraft with good characteristics in at least some area of the flight envelope ... or they would not have been selectedf for production!

By mid-1943, the bombing was taking effect and there were fewer and fewer well-trained German pilots coming down the pike who were having a very hard time surviving their first ten mission to become seasoned verterans and experts in their own right. The Germans were having a hard time fielding enough gasoline, and propellers were becomming as valuable as airframes by late-1944. The Germans lost to superior numbers with virtual parity in equipment, except for the jets, which were too few, too late. The Ta-152, as I have said many times before, was ... in my opinion ... a non-relevant aircraft with too few delivered to do any good and an average or worse kill-to-loss ratio, which may well have been caused by the overwhelming numbers of Allied fighters flying over Germany at the time. Whatever the reason, the Ta-152's did not affect the war to any degree at all.

The size of Germany is about 1 or two of our 50 states, depending upon the sates, and they came very close to winning WWII. You don't do that with inferior equipment, inferior manpower, or inferior anything. Their Achilles heel was Adolph Hitler and his group of advisors, not the German people, who, by the way, didn't want war as much as escape from the poverty caused by the Treaty of Versailles.

Getting long-winded so I'll stop.


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## Gaston (Mar 26, 2012)

Juha said:


> In his 56th Fighter Group book pp. 21 and 23 Freeman writes on early 47Cs "As combats had taken place near same level as the bombers, many of the group's pilots had been forced into slow turning and climbing actions. It was clear that the P-47 was no match for the Bf 109 or Fw 190 in such circumstances..."
> 
> Juha



That's a very interesting quote Juha, I had never seen it, and thanks for bringing it: I already knew the P-47D could likely not cope with the Me-109G in high altitude spiral climbs, especially to the right, which is why when one P-47D did it in one combat account (at 140 mph, on the deck, after 3 consecutive climbing 360s!!!) I speculated in my post that the Me-109G in question must have had gondolas...

I can quote another pilot with a similar conclusion about spiral climbs: Johannes Steinhoff, who said (from memory): "The best way to escape was a climbing spiral (to the right?), as the neither the P-51 or the P-47D could cope with that maneuver. The P-38 however could follow us and was an especially dangerous adversary".

This P-38 "dangerousness" is not supported by the combat/loss/kill numbers in Europe, where the P-38 was seen as a "relief" by German pilots, I think for good reasons at high altitudes...

I did find a surprising amount of P-47Ds out-spiral climbing the Me-109G however, but usually this was most common precisely around May 1944, just when the new "Bombers Only" Luftwaffe directive had its greatest influence on German operations (This directive is an absolutely huge historical factor that remained, in a more diluted form, for the rest of the war). This directive, in practical terms, yielded a disproportionately large number of gondola-equipped and non-maneuvering Me-109Gs for the month of May 1944, leading to a huge numbers of US "Ace in a day" during that particular month, a very visible "Ace in a day"-making effect to observe in the linked combat accounts when you look at the date: May 1944 is indeed a very special month in the story of the Air War over Europe...

I think the mid-1943 time period of Juha's quote is crucial as well: The early P-47Cs may still have been facing the sleeker G-2/G4s without gondolas, and they themselves were not yet the fully evolved P-47D with familliar pilots.

Note however that being "forced" to slow "turning and climbing actions" suggests to me spiral climbs, which still leaves room for the Me-109Gs not coping in pure horizontal turns. The FW-190A might still be able to contest horizontal turns with the P-47C at this height, but was not climbing competitively compared to a Me-109G... 

Later in 1944, the Me-109Gs would try turning horiontally with the P-47D at 22 000 ft., and, in the words of one account: "After two turns they quickly lost interest and rolled down and out."

It is well established in my mind that a "clean" gondola-less Me-109G in a right hand climbing spiral is something the P-47D cannot easily follow: It could be the "unseen" tactic of successful German pilots, not recorded in US victory combat accounts by virtue of its success... It is equally clear to me climbing spirals are not a common tactic without a very favourable situation set-up, as barely hanging on in horizontal turns is about all most turn fighting seems to manage... 



Juha said:


> What is interesting is that Soviet tests were in line Finnish tests and combat experiences. The only exception from that rule is LaGG-3 Series 28 which Finns thought was clearly poorer turner than the Soviet tests showed. Here the combats were as typical to Eastern Front mostly fought at fairly low level, so nearer to the circumstances in which the Soviet tests were flown.



I think some of these aircrafts were actually tested, then some where calculated from that, the nonsensical ones like the Lagg-3 being the calculated ones (or from grossly stripped and cleaned airframes): Take for instance the Spitfire Mk V being significantly out-turned by the Mk IX, 18.8 to 17.5, which Grep P said was the reverse of what "Planes of Fame" observed... (Brit tests showed a very close parity at all altitudes in sustained turns: I lean a little towards "Planes of Fame" on that!).

American tests also had the Zero out-turn the P-47D in less than one turn, the P-51D in 1.5 turns, and the P-38 in 2 turns: Makes sense doesn't it? The P-47D also outclimbed all of them in the test, and had the slowest accelerating dive... This was P-47D Bubbletop however, an issue I address below...

Another US test has the P-51B getting behind the P-47D Razorback in around 3 turns: Absolutely laughable when you compare the sum of their respective combat accounts, but in agreement with Soviet Tsagi tests and the above Zero comparison... It's either or: Either you choose the tests, or you choose the combat accounts. 

Sorry, but I have examined this for 15 years, and after much sweat and tears I have finally come down on the side of the shooting... And never looked back... I am sorry for all the WWII testing veterans, but the procedures they used just sucked: They produced the expected results, and the combat shows just the opposite (as do the German tests conclusions for both the FW-190A and the P-47D: I guess they were just better testers...)

(Completely off-subject: Combat accounts, interestingly, also reveals a *huge* gun jamming problem on the P-51 when maneuvering hard, for all P-51s, including the D: Despite improvements, gun jam statistics confirm this on a month by month chart, showing [despite 100+% improvement accross all the types when maintenance improved and altitudes got lower in June to late 1944] that the P-51 jamming rate always stayed at 2-3 X that of the P-47D, including for the P-51D, but on the B gun jamming is just of epidemic proportions: You almost never fired your full ammo load on any gun on any Bs(!) is the strong impression you get reading the accounts, and that remains just as true as ever in 1945(!)... P-47 jams seem absolutely non-existent in comparison... And still one in six to one in eigth P-51D mission ended with just one gun left firing or nothing at all... Sorry for the disgression, but maybe this will illustrate to you why I rely so heavily on real-life combat reports, and tend to give flight "tests" a very distant second seat...) 

Next post


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## Gaston (Mar 26, 2012)

Continued...

As for the later P-47D Bubbletop issue, you have to keep in mind that, in my proploading theory, more power and bigger paddle-blade props are *not* a good thing for *sustained* level turning (increased prop loading means increased wingloading, remember?), so the later, more powerful P-47D Bubbletops may have had just as good an initial turn radius as a Needle prop Razorback, but a serious deficit in sustaining a high turn rate compared to that same Razorback... It would seem from the combat reports I posted that the Bubbletop was a big step back in true sustained dogfighting maneuverability... It could no longer compete with the FW-190A but still did well enough vs the Me-109G, but no longer with such a crushing superiority as it had pre-paddle blade Razorback, say early half of 1944. 

I know many Jug pilots claim the Paddle-blade was a huge boost in maneuverability, but they make the same claim for the extra power of the later models, and all of that is just not consistent with the aggregate of P-47 combat reports: A marked decline in competitive turning vs the FW-190A from June-July 1944... But then again, maybe the FW-190A just got better with its own paddle-blade wood prop used in a heavily downthrottled fashion? This was exactly how one FW-190A-8 pilot described using it, citing the "bite" of the big prop at reduced power as a big factor to win reduced-throttle turning fights down on the deck...

As I noted, the Russian 27 seconds turn time for a P-47 Razorback, and 21-22 seconds(?) for the P-51B, is in good agreement with the US tests of the two types: It does sound convincing, but when you have read your umpteeth thousanth P-47D combat report, all of them saying the same (completely opposite) thing, these slow-turning P-47Ds just seem like a particularly imaginative fairy tale from Alice in Wonderland...

Furthermore, I have seen guncam footage of a prolonged dogfight between the FW-190A-8 and a P-47D Razorback, over several 360s, and the obsessive reliance of the P-47 on its turning performance, despite being hit, is well supported by the incredible turning rate it displays against its background compared to any other gun cam footage I have seen: A Me-109G would have been left in the dust, and the footage lasts so long only because it is an FW-190A doing the filming...



Juha said:


> One must remember that the Soviet tests were flown at 1000m (3048ft) and most of Jug combats were fought at much higher level. Jug was designed for high altitude fighter but on the other hand 109G would also have suffered less from its heavy control forces higher up..



Which is exactly why the Me-109 was kept in production: The FW-190A was not as good past 22 000 ft., and the Me-109G out-turned it up there for reasons that likely had little to do with power output, but rather with wingloading becoming more important than "prop-loading" in the thinner air...

I think the resistance of the prop to assymetrical angles simply went down faster with thinner air, becoming an increasingly less important factor to loading up the wing...

Contrary to legend, Jug maneuverability did not improve all that much relatively to other types with altitude, at least not to any hugely significant degree: It did just as well down low, despite what some Jug pilot claim: The overall combat record again speaks louder than individual pilot impressions... 

In a Me-109G-6 I would rather face a P-47 above 15 000 ft but below 25 000 ft., climbing above it to then dive to attack, choosing a "clean" gondola-less Me-109G to do so... 

In a Me-109G-6 against a P-51D Mustang scenario, I would rather face the P-51D below 15 000 ft. with a full three cannons, and would try to avoid fighting with it above 20 000ft, but still try to get the diving surprise from up there at first... I would keep in mind that a P-51D with "purple passion" 150 octane fuel (from July-August 1944 mainly) can out-climb my G-6 even if I was flying a "clean" gondola-less Me-109G-6, and that the MW-50 of the G-14 is of no reliable help in prolonged climbs or dives (oil starves in climbs or blows up the engine in dives): I would leave MW-50 out for weight/maintenance reasons, which most of them did anyway... I would use reduced-throttle horizontal turns on a three-cannon G-6, if the P-51D didn't know well enough to cut the throttle (in which case I would cut the throttle further, just as Karhila advises), and would go head-to-head with it at reduced power (again with three cannons as a preferred set-up) if it didn't turn with me but climbed above to dive on me.

And I would be dearly wishing for a FW-190A...



Juha said:


> combat reports are reports by the winners, loosers usually didn't write reports, especially those shot down over enemy territories. And because there are so few LW combat reports around we have little info from LW winners. I have read several memoirs of LW aces, but most of them are written by JG 52 aces, so not much use here and IIRC Knoke's memoirs isn't very reliable..



I did keep that in mind and this is a very valid point: After all, the enemy pilots are shown doing something wrong somewhere! However, you can still gather a "picture" from the repeated facts of hundreds upon hundreds of accounts... And some individual accounts are much more significant and detailed out of the hundreds, which is exactly where my "prop loading the wing" theory comes from: From a pilot's combat description in minute detail...

Many unexpected things show in these accounts: I mentionned the P-51 gun jams, but even more interesting is that, in late 1944, German pilots usually take much more effort to shoot down than their early 1944 "more experienced" colleagues, despite *far* worse odds: This seems related to the increasing Western prevalence of the FW-190A (70% of Western Front front-line strength, by late 1944), but also to pilots better informed on how to fight against the US: Less use of speed, of vertical maneuvers, and more use of horizontal turning.

Quote: "Every Ace sent to me from the Eastern Front was shot down on the Western Front" 

These Eastern Front pilots were used to fast dives and zooming in their Me-109Gs, against slower and especially lower Russian fighters. In the West the Germans very rarely had the altitude advantage, and had to resort to unfamilliar tactics for which the Me-109G was less well-suited. I remember one account in particular: "I told [this Eastern Front ace] to always turn against Allied fighters, and to never use the vertical. He did not listen to me, and in combat he went in a full MW-50 climb, with smoke pouring from the exhausts of his Me-109G-14AS, and was immediately shot down."

Another similar (if non-Eastern Front related) example: "Many times I had told Oseau the FW-190A was better than the Bf-109, but being an old Me-109 hand, he preferred it".

This reminds me of an amusing American quote, not really related but just for fun: "We designed the P-47D for high-altitude fighting and the P-51 for low-altitude bombing: Given where they ended up, it's a wonder we won the war!"

Gaston


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## wuzak (Mar 26, 2012)

Gaston said:


> This reminds me of an amusing American quote, not really related but just for fun: "We designed the P-47D for high-altitude fighting and the P-51 for low-altitude bombing: Given where they ended up, it's a wonder we won the war!"



It may be an amusing quote, but it is completely incorrect.


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## Gaston (Mar 26, 2012)

wuzak said:


> I think you've jumped on the wrong person here.
> 
> It is Gaston who is basing his thesis on combat reports - mainly from ww2performance.com, which I would guess are predominately allied reports.
> 
> ...



Why don't you go look up the German claim of the P-47D (needle-tip prop) out-turning the Me-109G?: It's in the recent book "KG 200: On Special Missions"

The Rechlin testing center, on Dec 10 1941, also issued a report stating the FW-190A out-turned and out-rolled the Me-109F at all speeds.

But what do they know compared to your great science? 

Maybe your great science can explain this?:

http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg

It does seem to show the P-51 turning like crap for a long while at low speed before the throttle is cut, and *stays* cut, saving the day...


Gaston


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## Denniss (Mar 26, 2012)

davebender said:


> As far as I'm aware the December 1941 version is the only version of the Heuschrecke ordered into mass production. If not for the war Germany would have procured at least 200.
> 
> Procurement of any other Heuschrecke model is only speculation. Personally I have my doubts about the turret unloading crane making it past prototype. I think Heer artillery personnel would prefer additional armor protection over the weight of the crane.


Heuschrecke was the vehice with detachable gun turret, not depicted in this image. Superstructure clearly shows this vehicle is based on a modified tank chassis, not on the special-made Geschützwagen. See the image linked above for a real Heuschrecke. The Sd.Kfz.165/1 was never named Heuschrecke.


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## wuzak (Mar 26, 2012)

Gaston said:


> Maybe your great science can explain this?:
> 
> http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg
> 
> ...



Maybe dropping the flaps had something to do with it. It is also unclear what measures the German pilot took.

Surely if cutting power enabled the P-51 pilot to turn tighter than the Bf109 pilot that would also hold true for the Bf109 pilot?


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## GregP (Mar 26, 2012)

If the P-51 was going faster than corner speed (about 265 mph) then cutting teh throttle would help the turn until he got to corner speed. After that he is just losing ground. Also, if he was going faster than corner speed, the correct response is either to cimb until corner speed is reached or dive away and extent for either escape or reengagement.

Gaston, how does increasing the propeller blade area hurt turning ability? 

That doesn't make sense. All it did was to increase thrust, particularly at lower speeds.

Last the Me 109 had automatic slats. If the Me 109 were traveling fast eniough so the slats didn;t open, it was less maneuverable. Once the slats open, it is moer maneuverable, though the slats DO open asymmetrically if not in coordinated flight and momentarily spoil an aim.

According to everything I have read, the bubble-top P-47D was a step forward, not backward. You might notice we are still, to this day, flying mostly bubble canopies. Think of the F-22, F-35, F-18, Eurofighter, Su-27/35/37, J-10 ... I can't think of many modern fighters without a bubble canopy.


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## Tante Ju (Mar 26, 2012)

GregP said:


> Last the Me 109 had automatic slats. If the Me 109 were traveling fast eniough so the slats didn;t open, it was less maneuverable. Once the slats open, it is moer maneuverable, though the slats DO open asymmetrically if not in coordinated flight and momentarily spoil an aim.



I think you got it wrong. Slats do not depend on speed for open, but the degree of incidence of wing! Meaning they pull out if the wing is very close to stalled, or if aircraft is turned as hard as it can be, ie. pulling very high G-s. Granted they were not likely not open at high speed, but this is because at high speed you have plenty of speed for manouver without need to reach maximum degree of incidence - you still pull many many g. So its not really that slats add "manouver" ability, but ability to pull more when speed is so low that high angle of wing is needed or otherwise you stall out, ie. at low speeds.

At high speeds its very easy to pull 5-6 g without being near the stall.


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## Juha (Mar 26, 2012)

Hello Gaston
I have very little time so only a few comments.



Gaston said:


> ... Note however that being "forced" to slow "turning and climbing actions" suggests to me spiral climbs, which still leaves room for the Me-109Gs not coping in pure horizontal turns. The FW-190A might still be able to contest horizontal turns with the P-47C at this height, but was not climbing competitively compared to a Me-109G...



Not necessarily IMHO probably means slow speed turning, slow speed climbing and slow speed spiral climbs, all three and 109 was good in all those.

Because you are intering in 1944 air fighting if you don’t already own a copy of Ospreys VIII Fighter Command at War “Long Reach” I highly recommended it. It is in fact a reprint of a study made by the VIII FC which was originally printed in May 44 in which 24 US aces tell their views on tactics against Jagdwaffe at the time when P-47 was still the main fighter type of the VIII FC.

Which was better questions tended to produce mixed answers. Some quotas from the Long Reach:
Lt Col John C Meyer CO 352 FG "...We have found that the turnig characteristics of the P-47 as against the Me 109 and Fw 190 are very nearly equal..."

Capt Virgil K Meroney 487th FS/352 FG
"...There is a lot of argument on wheather the P-47 can out-turn the Fw 190 and the Me 109. I feel that it all depends on the situation of the moment..."
1Lt Jesse W Gonnam 352nd FS/353rd FG
"...I believe the P-47 can both out-turn and out-climb either the Me 109 or the Fw 190" He specifies this later to high speed and at high altitude situation.



Gaston said:


> ... Take for instance the Spitfire Mk V being significantly out-turned by the Mk IX, 18.8 to 17.5, which Grep P said was the reverse of what "Planes of Fame" observed... (Brit tests showed a very close parity at all altitudes in sustained turns: I lean a little towards "Planes of Fame" on that!)...



You must remember that LF IX (Merlin 66) was a bit different animal than later F.IX (Merlin 63) which on the other hand had better power loading than early F. IX (Merlin 61) under FTH.



Gaston said:


> Another US test has the P-51B getting behind the P-47D Razorback in around 3 turns: Absolutely laughable when you compare the sum of their respective combat accounts, but in agreement with Soviet Tsagi tests and the above Zero comparison... It's either or: Either you choose the tests, or you choose the combat accounts.



Tsagi tested Mustang Mk I (AG348 ) and speed at 4600m (587km/h), the designation used in some Soviet docus, NA-73, and V1710-F3R engine. So not P-51A but XP-51 in USAAF parlance)
- 23 sec, weight 3884kg 

Juha


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## Jabberwocky (Mar 26, 2012)

Soviet Spitfire tests give wing area, and its clear that the Mk V tested was a clipped wing version, while the Mk IX tested was a full wing version.

This helps explain the difference in turn times.


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## Jenisch (Mar 26, 2012)

I know Gaston from the IL2 simulator Ubisoft forum, and he is well know as a troll by aircraft performance discussions there. I don't recommend lose time with him.


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## Gaston (Mar 26, 2012)

wuzak said:


> Maybe dropping the flaps had something to do with it. It is also unclear what measures the German pilot took.
> 
> Surely if cutting power enabled the P-51 pilot to turn tighter than the Bf109 pilot that would also hold true for the Bf109 pilot?



Absolutely it would, but not if the Me-109G pilot did not believe that it did... I think the Me-109G probably had a slight edge over the P-51D in downthrottling the engine in sustained horizontal turns, *if *the pilot was willing to go far enough down that counter-intuitive path... I think even the three-cannon Me-109G could compete if downthrottled... Karhila recommended a reduced throttle to 250 km/h (160 mph) for the best turn rate: Not necessarily a widespread opinion...

Note how the P-51 pilot throws conventional theories to the wind, and uses coarse prop pitch at low speeds in a sustained turn...

Gaston


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## Gaston (Mar 26, 2012)

Jabberwocky said:


> Soviet Spitfire tests give wing area, and its clear that the Mk V tested was a clipped wing version, while the Mk IX tested was a full wing version.
> 
> This helps explain the difference in turn times.



How is it clear? Do you have the dates for these "flights"?

Gaston


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## Gaston (Mar 26, 2012)

GregP said:


> If the P-51 was going faster than corner speed (about 265 mph) then cutting the throttle would help the turn until he got to corner speed. After that he is just losing ground. Also, if he was going faster than corner speed, the correct response is either to cimb until corner speed is reached or dive away and extent for either escape or reengagement..



OK, guys, let's keep the 265 mph "corner speed" in mind (which is really 320 mph as measured in 1989 by the SETP, but no matter): 

http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg

The fight starts with the P-51 closing on a landing Me-109G at the huge altitude of 150 ft,, the shooting starting at 300 yards, which shooting is carried on to 50 yards, indicating a moderate closing pace over the Me-109G's landing speed: 300 mph? Doubt it: Let's say 250 mph... OK, let's say 300 mph just to be 35 mph above the "corner speed" (at this unproven horizontal corner speed value, at full continuous power, which turned out to be 55 mph below the actual reality when tested in 1989 with modern instruments by the SETP, remember?)... I say "horizontal", because a dive pull-out unloads the prop's load during the dive, which could "artificially" lower the true 320 mph horizontal corner speed as measured by the SETP...

He then pulls up to avoid AAA. Let's say 290 mph at the very most now... 25 mph above the mythical Corner Speed...

Then a turn fight starts at 500 ft.... He is being out-turned by a Me-109G-6 (given the May 1944 timeframe). He then cuts the throttle and this *and immediately stops the Me-109G-6's gains*.

This happens *over several 360s*, because "every time I got close to the airdrome they opened fire with light AA guns".

He *gradually* works the Me-109G away from his airfield, suggesting again that this occurs *over several 360s*. Speed could not be above 220-230 mph now, at best... 35-45 mph below corner speed...

He then went to do some further downthrottling, going from stopping him "to cut inside me" to "commenced to turn inside him as I decreased throttle settings", all this after numerous 360s, at 500 ft. altitude at the most...

The striking thing is there is no delay mentionned: If he was at a much higher speed that prevented him to turn tightly, how come there is no delay between the lowering of the throttle and the reduction in speed gradually improving his turn?: It would take a delay for the speed to go down, if he was in fact going too fast: No such thing here, where the turn superiority is instantly gained the moment the throttle is lowered: This is mentionned twice in clear language:

-"He stopped cutting me off *as* I cut throttle"
-"I commenced to turn inside him *as* I decreased throttle settings"

If this was lowering speed to a very hypotethical "Corner Speed", it would have been:

-"He stopped cutting me off *after* I cut throttle"
-"I commenced to turn inside him *after* I decreased throttle settings"

Confirming that the effect is both immediate and permanent, and not transient, is that there is *no* mention of throttling back up, but *two* mentions of throttling down: Throttling down produces instantly a superior turn rate permanently compared to a fixed reference point, the chasing Me-109G-6.

And if you don't want to believe it, show me where he mentions that he throttled back up to save his life, for which he cared as much as you do, in addition to providing a combat report of some use to his fellow pilots...

This jives rather well with Karhila's opinion of an optimal, very downthrottled, 160 mph sustained turn speed for the Me-109G-6 does it not? As well as his comment: "When the enemy decreased power, I used to throttle back even more." No mention of throttling back up here either, what a curious coincidence...

virtualpilots.fi: 109myths




GregP said:


> Gaston, how does increasing the propeller blade area hurt turning ability?
> 
> That doesn't make sense. All it did was to increase thrust, particularly at lower speeds...



You mean *Karhila* doesn't make sense?: " I found that when fighter pilots got in a battle, they usually applied full power and then began to turn. *In the same situation* I used to decrease power, and with lower speed was able to turn equally well." virtualpilots.fi: 109myths

I've explained many times over why thrust is leveraging wingload when it comes from so far down the nose. That is why needle-tip prop P-47Ds (which are always Razorbacks for needle tip props), out-turn the Me-109G in sustained turn, as the Germans themselves found out in their own tests. 

It is the same with downthrottling: Less trust gains you more reduction in radius than loss in speed, up to a point, and that, unlike what you say, does make perfect sense...



GregP said:


> Last the Me 109 had automatic slats. If the Me 109 were traveling fast eniough so the slats didn;t open, it was less maneuverable. Once the slats open, it is moer maneuverable, though the slats DO open asymmetrically if not in coordinated flight and momentarily spoil an aim..



That doesn't explain why the P-51's turning performance suddenly improves relative to that, at clearly very low speeds, when the throttle is cut.



GregP said:


> According to everything I have read, the bubble-top P-47D was a step forward, not backward. You might notice we are still, to this day, flying mostly bubble canopies. Think of the F-22, F-35, F-18, Eurofighter, Su-27/35/37, J-10 ... I can't think of many modern fighters without a bubble canopy.



As I said, it has to do more with a lesser maximum power and skinnier needle-tip props than the canopy...

Gaston


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## FLYBOYJ (Mar 26, 2012)

So Gaston - have you ever flown a REAL aircraft????? A REAL high performance aircraft?


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## GregP (Mar 26, 2012)

rtGaston,

I read your link. Speed isn't mentioned at all. How do you get your conclusions from a report of such a general nature? No speed is mentioned, a P-47 turning inside an Me-109 pilot in one report is not in any way proof of performance. It means one guy of unknown experience flying at unknown speed turned inside one Me-109 being flown by a pilot of unknown experience and unknown airspeed ... and the Me 109 guy lost. That's about all it shows.

Also, 265 mph is NOT 320 mph. The correct airspeed is around 265 - 270 mph, ask any Mustang pilot. They know the V-N diagram. The one I have is not detailed enough to decipher 2 - 3 mph, but 265 is right there about the right place. My own P-51 pilot's manual is currently in my household goods that I haven't unpacked yet.

You never answered my request for you to further explain your "prop-to-tail ratio" either. At least explain the "prop" part and tell me how dividing the "prop" by the lift force (the "tail") creates a number that means anything.


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## FLYBOYJ (Mar 27, 2012)

Gaston said:


> OK, guys, let's keep the 265 mph "corner speed" in mind (which is really 320 mph as measured in 1989 by the SETP, but no matter):
> 
> http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg
> 
> ...


All based on flying a PC sim?!?!


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## Gaston (Mar 28, 2012)

GregP said:


> You never answered my request for you to further explain your "prop-to-tail ratio" either. At least explain the "prop" part and tell me how dividing the "prop" by the lift force (the "tail") creates a number that means anything.





Ok, one last time: At WEP I assume 1800 hp is 1800 lbs of force in the prop disc: 80% of that pivoting back compared to the trajectory is 1440 pounds (working assumption), and *I would use as a rule of thumb that this 80% prop face value means that, for every 1° of angle of attack increase, there is also 0.8° of extra lift through thrust slanting* (0.7° if it was 70% of the disc face tilting back, but here 0.8° because it is 80%).

Tilt of the prop disc face is only an initial set up event: It lasts a proverbial micro-second: All further rotation is centered near CG-CL area...

This 1440 lbs prop value is gradually built up by 205 pounds for each AoA degree to 7°, maximum sustained angle of attack, totalling 1440 pounds at 7° as the assumed prop's fully topped-out resistance to assymetrical air inflow (due to turn assymetry). 

*The pilot stick is not beating the 1440 pounds at the nose by itself*: *The pilot cannot "feel" those loads, only the aircraft does, ever since the CL moved in front of the CG during its micro-second collapse*... The CL is shifted in front of the CG now, and the increasing turn gives the CL 7° AoA of lift + 5.6° of thrust slanting: Total : 12.6° of equivalent AoA lift.

Say a 10 000 lbs aircraft at 7° AoA means 3Gs: That's 30 000 lbs of lift: + 80% of that means + 24 000 lbs of lift. Total: 54 000 lbs of lift.

A void is created above the wing when the CL shifted down and forward: This is the work of the mysterious "*CL Collapse*", so the top/bottom wing pressure imbalance IS there as the angle of thrust rotates down on top of the increasing AoA to the tune of plus 80% over the AoA value (up to presumed 7° "real" AoA max.)... That upper wing void seemingly remains during the turn, and increases in proportion to the AoA + thrust slanting total... (Weird!)

This above-wing extra void might be "maintained" by the bottom boundary layer leaking over the wing, going forward from the trailing edge (this is of course unknown at this point)... This is a direct result of the prop's initial resistance to the elevator: *Resistance at both ends means slight CL "collapse": *Barely a micro-second, and of course simultaneous with the initial prop "set-up" tilt...

If the CL is collapsing down and forward, it cannot be anywhere near the point of rotation during this micro-second collapse phase.... This is not hard to visualize! The aircraft is being loaded at both ends for a micro-second, which squeezes the CL forward as it goes down from the extra load...

After that:

Going straight *down*: CG with 30 000 lbs at 3 G. Going straight up *in front of that now*: Total CL at 54 000 lbs.

30 000 lbs *down* and 54 000 lbs *up* are inter-acting with each other as a "scissor action", relieving the elevator's effort to lift the nose, which is why the pilot cannot feel the prop's resistance to assymetry during the turn...

1440 lbs at the prop is not going straight downward for its part, but it does not want to go back and up either, since it pushes forward and slightly down....: To keep in balance the combined scissor action, the leverage advantage of the prop must be close to 30 000 lbs + 54 000 lbs divided by 1440 lbs: 58 to one for each up/down force's lever, 29 to one for both levers combined: For a ten foot nose that means here the CL is around 4.13793 inches in front of the CG when it has shifted forward under the initial micro-second elevator effort...

Why close to 29 to one? Because the nose does go up in the end, and the elevators also do help lift the nose a little after all...

And 54 000 lbs of load on the wing *is* like 5.4 Gs of wing bending at 3 Gs of turning....

And that is how engine power can affect the wingload.

And no, I can't make it any more simpler than that... If you don't want to understand it, don't.

Gaston


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## Tante Ju (Mar 28, 2012)

Can somebody explain this to me?


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## wuzak (Mar 28, 2012)

Gatson is the only on that can do that. But he has an inability to explain his theories.

He needs to draw up some simple diagrams to help explain what the hell he is on about.

btw Gaston, 1800hp does not necessarily equal 1800lbs thrust. (And don't forget the exhaust thrust, which could be 150-300lbs worth on Spitfires, IIRC).


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## Shortround6 (Mar 28, 2012)

AH HA! it is all clear to me now!!!

The Hellcat turned well, not because of it's big wing, but because it's engine and prop were mounted at a down angle which means that it started with a negative "prop-to-tail ratio" and so stayed less than most other fighters at any angle of attack.

I am still having trouble with the "micro-second collapse" affecting a 360 degree turn that takes 18-24 seconds though


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## FLYBOYJ (Mar 28, 2012)

So Gaston, you experienced this first hand when?!?


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## DerAdlerIstGelandet (Mar 28, 2012)

FLYBOYJ said:


> All based on flying a PC sim?!?!



Come on Joe, you know a PC sim is just like flying the real thing.


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## drgondog (Mar 28, 2012)

wuzak said:


> Gatson is the only on that can do that. But he has an inability to explain his theories.
> 
> He needs to draw up some simple diagrams to help explain what the hell he is on about.
> 
> btw Gaston, 1800hp does not necessarily equal 1800lbs thrust. (And don't forget the exhaust thrust, which could be 150-300lbs worth on Spitfires, IIRC).



Wuzak - as usual you are impeccably tolerant and kind..... 1800hp will NEVER equate to anything near a 1hp:1pd thrust - inclusive of exhaust thrust - for any propeller driven aircraft designed and produced, theoretical or actual...


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## tyrodtom (Mar 28, 2012)

This is like a Andy Kaufman joke, ( remember him on Taxi ?) i'll bet even Gaston is laughing.
The joke is on us, for taking the time to read his nonsense.


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## FLYBOYJ (Mar 28, 2012)

Gaston said:


> I assume 1800 hp is 1800 lbs of force in the prop disc:


 Assume wrong. What kinds of force? Torsional? Tension? Is the load constant through the length of the blade? Is it at the hub as well? You know, I'm all one for free speech and I value the opinions of everyone who participates on this forum, but from what I have read so far you're totally talking out of your @ss. I'm not one to verify what you say mathematically (perhaps Bill might do that if he has nothing else to do in the world), but so far you written long threads and made little sense.


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## drgondog (Mar 28, 2012)

tyrodtom said:


> This is like a Andy Kaufman joke, ( remember him on Taxi ?) i'll bet even Gaston is laughing.
> The joke is on us, for taking the time to read his nonsense.



TOM - I personally agree. There are only two options. One, despite many reasoned requests for 'the math behind his assumptions' or even a translation of various forces into a free body diagram, he continues to mangle physics as articulated in the the english language like someone with Tourette's Syndrome. Two, he truly believes what he is saying.

I would prefer to think that he is not truly demented and therefore falls into the category of having enormous fun with the poor guys he sucks into a dialogue with him more than once.


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## drgondog (Mar 28, 2012)

Tante Ju said:


> Can somebody explain this to me?



Tante Ju - if you spend one more minute reading and digesting his prose, I believe you have wasted at least 60 seconds of the rest of your life.

Warm Regards,

Bill


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## FLYBOYJ (Mar 28, 2012)

drgondog said:


> *"despite many reasoned requests for 'the math behind his assumptions' or even a translation of various forces into a free body diagram, he continues to mangle physics as articulated in the the english language like someone with Tourette's Syndrome"*


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## tomo pauk (Mar 28, 2012)

The latest ten posts here are pure gold


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## Jenisch (Mar 28, 2012)




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## GregP (Mar 28, 2012)

Gaston:
1.	Thrust in pounds does not equal Horsepower.
Dynamic Thrust (lbs) = Power (HP) / (Velocity (knots) * (6076/(3600 * 550)))
By way of example, a Grumman Hellcat at combat was about 12,325 pounds at combat weight. It had 2000 HP, but let’s say he was using 1800 HP to stay with your example. The equation above is NOT for static thrust, it is for dynamic thrust. At 174 knots (about 200 mph) the thrust is 3,371 pounds for a thrust to weight ratio of .2735, which is typical for a WWII fighter. You aren’t even close. There are other ways to calculate this force within a few percent, but they won't equal the horsepower being used.

2.	I do not know what “80% of it pivoting back compared to the trajectory” even means. It doesn’t make sense to me, but I am not dismissing it. Perhaps the words are just not quite right for me to see it. But, the thrust is the thrust. It does not act along the line of wing incidence. Most engine mounts were canted downward several degrees and had several degrees of side thrust compared to the fuselage datum line The wing usually had several degrees of positive incidence.

3.	The angle of thrust to the angle of attack is NOT the same as the angle of wing incidence due to down and side cant, but is reasonably close. The actual angle of thrust in a propeller fighter is almost always less than the angle of attack due to down thrust built into the engine mount. The component of thrust along the angle of travel is the thrust times the cosine of the angle of attack, and the component that adds to lift is the thrust times the sine of the angle of attack. It is not constant but varies with the angle of attack.

4.	The Center of lift does not move unless the airflow goes transonic or supersonic.

5.	The pilot cannot feel the thrust in the stick at all. He feels the elevator and aileron out of trim forces only. That’s why he needs trim tabs. He feels the rudder out of trim force in the rudder pedals if he keeps the ball centered. If he doesn’t, he just slips or skids through the air without feeling it … unless the slip or skid is enough to induce a spin.

6.	A 10,000 pound airplane at 3g needs 30,000 pounds of lift to fly at 3 g, not 54,000. Any added lift from the propeller thrust just decreases the amount of lift the wing needs to produce. 3g – 3g. In Algebra, the “=“ sign means EQUALS. 30,000 pounds does not equal 54,000 pounds … it equals 30,000 pounds. The real only “extra lift” needed is to counteract the tail downforce. So the 30,000 pounds turns into a bit more in a conventional wing-first aircraft and bit less in a canard aircraft (because the forward tail lifts upward instead of downward) but not an extra 24,000 pounds.

7.	There is no void created above the wing; the center of lift doesn’t shift since the local airflow is not either transonic or supersonic.

8.	Your theories are so far off from the aerodynamic formulas that produced the actual aircraft as to be out of the ballpark ... they're craptacular, to quote Bart Simpson. Gaston, the WWII fighters FLEW AS DESIGNED, meaning the designers knew what they were doing and their formulas were correct. As I said before, you need to take a course in aerodynamics, not try to reinvent the science. 


I have exceeded my prop-to-tail ratio for this evening and need another beer. Gaston, you need one, too ... and buy that aerodynamics text before you read another combat report that has someone turning in 360° circles for 50 turns. More than 2 - 3 was a death sentence from the targets friends and wingmen (not necessarily the same people). Single engagement, NOBODY went for 10 horizontal turns except maybe in a Lufbrey with a few friends around also in the Lufbrey. Oh wait, that was WWI.

Because of the ratio, I still need some tail ... it's late ...


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## Elmas (Mar 29, 2012)

I smell a Nobel Prize for Physics for the brand new theories explained in these threads........


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## drgondog (Mar 29, 2012)

Elmas said:


> I smell a Nobel Prize for Physics for the brand new theories explained in these threads........



Elmas - the odors you sense are found in many pastures and known far and wide as bovine fecal matter - highly concentrated and in this case, and delivered by the ton (or Tonne). I believe the Brits shipped this material by sail and noted on the manifest as Shipped High In Transit..


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## Milosh (Mar 29, 2012)

GregP said:


> NOBODY went for 10 horizontal turns except maybe in a Lufbrey with a few friends around also in the Lufbrey. Oh wait, that was WWI.



Bf110s flew Lufbery's in WW2.


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## tyrodtom (Mar 29, 2012)

drgondog said:


> Elmas - the odors you sense are found in many pastures and known far and wide as bovine fecal matter - highly concentrated and in this case, and delivered by the ton (or Tonne). I believe the Brits shipped this material by sail and noted on the manifest as Shipped High In Transit..


 Just think of the play on words his name may be.
Gaston = ton (of) gas


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## drgondog (Mar 29, 2012)

Milosh said:


> Bf110s flew Lufbery's in WW2.



So did 109's and 190's and 410's and 51's and P-47's when they got cornered.


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## FLYBOYJ (Mar 29, 2012)

Gaston said:


> -"He stopped cutting me off *after* I cut throttle"
> -"I commenced to turn inside him *after* I decreased throttle settings"



I bet dollars to donuts IN A REAL AIRPLANE I'd be up your ass before you banked more than 10 degrees.

Gaston, you're an ARMCHAIR in more ways than one


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## Jenisch (Mar 29, 2012)

Gaston, I have a basic flight theory book for my private pilot course with just 81 pages of content. Since Portuguese is overall longer to write than English, you should find one with even less pages. I strongly recommend you to buy one.


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## FLYBOYJ (Mar 29, 2012)




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## GregP (Mar 29, 2012)

I realize some people used the Lufbery in WWII, but it wasn't anywhere near as prevalent as in WWI.

And I seriously doubt anyone would engage in consecutive 360° horizontal circles for 10 or more turns. If they did, they would never live to be a veteran.


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## Elmas (Mar 29, 2012)

FLYBOYJ said:


> I bet dollars to donuts IN A REAL AIRPLANE I'd be up your ass before you banked more than 10 degrees.
> 
> Gaston, you're an ARMCHAIR in more ways than one




A Friend of mine, Ten. Alberto Scano, of wich in this post

http://www.ww2aircraft.net/forum/aircraft-pictures/scuola-caccia-elmas-32016.html

told me an amusing little story about his training.
One Colleague of his was having an instructional session in a Link-Trainer.
The Chief Instructor, from outside, set the instruments in a position that simulated a flat spin and started shouting trough the intercom:

“You are in a flat spin!You are in a flat spin*!*You are in a flat spin*!*
Jump! Jump*!* Jump*!*”

The student pilot inside opened the canopy in a hurry and.....parachuted himself out of the linkTrainer....

The poor fella had to pay drinks for a whole month at the Officer’s Mess......

So I think other people here are parachuting themselves out of their armchairs.........


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## FLYBOYJ (Mar 29, 2012)

Elmas said:


> A Friend of mine, Ten. Alberto Scano, of wich in this post
> 
> http://www.ww2aircraft.net/forum/aircraft-pictures/scuola-caccia-elmas-32016.html
> 
> ...



LOLOLOLOL!!!!!


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## davparlr (Mar 29, 2012)

GregP said:


> I realize some people used the Lufbery in WWII, but it wasn't anywhere near as prevalent as in WWI.
> 
> And I seriously doubt anyone would engage in consecutive 360° horizontal circles for 10 or more turns. If they did, they would never live to be a veteran.



It was also used in Vietnam by Migs, as bait for non gun armed F-4s, according to wiki. "Dogfights" also mentioned its usage in Vietnam in one episode.


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## GregP (Mar 29, 2012)

The non-gun F-4's had sidewinders. If they worked, they were immune to the Lufbery circle, not have pilots and being very quick. Alas, the "working" missiles in VietNam were in the minority.


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## FLYBOYJ (Mar 29, 2012)

GregP said:


> The non-gun F-4's had sidewinders. If they worked, they were immune to the Lufbery circle, not have pilots and being very quick. Alas, the "working" missiles in VietNam were in the minority.


Actually it was the Sparrows that had an issue. The sidewinder had limitations on where and when it would work.

_"About 7500 AIM-7D and 25000 AIM-7E missiles were built, and the Sparrow was used heavily in Vietnam by the USAF and the U.S. Navy. The first combat kill was scored on 7 June 1965, when USN F-4B Phantoms shot down 2 MiG-17s. However, the initial combat results were very disappointing. The potentially long range of the AIM-7 could not be used, because unreliable IFF capabilities of the time effectively required visual identification of all targets. Coupled with the high minimum range of the missile of 1500 m (5000 ft) and poor performance against manoeuvering and/or low-flying targets, this led to a kill probability of less than 10%." _

Raytheon AIM/RIM-7 Sparrow


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## GregP (Mar 30, 2012)

FlyboyJ, You are, of course, correct. The main issue was that the F-4 had to keep illuminatuing the target after firing so the Semi-active Sparrow would guide. If the F-4 turned away, the missile would be useless. They NEEDED the sidewainder, but had more Sparrows.

Mental fart on my part ...


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## Gaston (Mar 30, 2012)

GregP said:


> Gaston:
> 1.	Thrust in pounds does not equal Horsepower.
> Dynamic Thrust (lbs) = Power (HP) / (Velocity (knots) * (6076/(3600 * 550)))
> By way of example, a Grumman Hellcat at combat was about 12,325 pounds at combat weight. It had 2000 HP, but let’s say he was using 1800 HP to stay with your example. The equation above is NOT for static thrust, it is for dynamic thrust. At 174 knots (about 200 mph) the thrust is 3,371 pounds for a thrust to weight ratio of .2735, which is typical for a WWII fighter. You aren’t even close. There are other ways to calculate this force within a few percent, but they won't equal the horsepower being used....



Good to know. So for similar leverage loads, a much smaller percentage of the thrust can be used... 3371 lbs is way more like it...



GregP said:


> 2.	I do not know what “80% of it pivoting back compared to the trajectory” even means. It doesn’t make sense to me, but I am not dismissing it. Perhaps the words are just not quite right for me to see it. But, the thrust is the thrust. It does not act along the line of wing incidence. Most engine mounts were canted downward several degrees and had several degrees of side thrust compared to the fuselage datum line The wing usually had several degrees of positive incidence.....



Imagine the vertical height of the prop, then put the micro-second initial pivot point at the bottom 20% height... If you increase AoA, the top of the prop by definition moves back compared to the trajectory, but here it does so for a micro second by dipping the CL and pivoting *within* the prop's face...

After that, pivoting is much more like you think, but the thrust slanting is set up in amplitude for each ° of AoA...



GregP said:


> 3.	The angle of thrust to the angle of attack is NOT the same as the angle of wing incidence due to down and side cant, but is reasonably close. The actual angle of thrust in a propeller fighter is almost always less than the angle of attack due to down thrust built into the engine mount. The component of thrust along the angle of travel is the thrust times the cosine of the angle of attack, and the component that adds to lift is the thrust times the sine of the angle of attack. It is not constant but varies with the angle of attack..



I see no conflict here.



GregP said:


> 4.	The Center of lift does not move unless the airflow goes transonic or supersonic.



In which case I presume it moves back to create Mach tuck? 

If it moved forward only under elevator action at lower speeds, how would you know about it? The elevator's downward tail action would in effect conceal the forward movement with something wanted, and the true extent of the CL's forward movement would be further hidden by the resistance of the prop...

Tilting the whole thing *at* the prop, even for a microsecond, is what makes the CL squeeze forward: It's easy to visualize...

You may think the prop will resist little, just like it resist little a mirror's drag slowing down its whole surface, but that is like lifting a long one-sided barbell straight up: Easy.

Try to induce a tilt while lifting that long barbell *with the heavy end off-center*, and the *longer* the handle the *worse* the effort...

That is exactly what the prop does when AoA increases... And you can test it yourself on the barbells, although the effect on the prop is actually much worse, because on top of the "off-centeredness" of lifting the nose off-center, slower air from turning starts to hit one side of the prop's front, slanting its thrust against your effort to hold it slanted...



GregP said:


> 5.	The pilot cannot feel the thrust in the stick at all. He feels the elevator and aileron out of trim forces only. That’s why he needs trim tabs. He feels the rudder out of trim force in the rudder pedals if he keeps the ball centered. If he doesn’t, he just slips or skids through the air without feeling it … Unless the slip or skid is enough to induce a spin.



I never said that he did. The now forward position of the CL insures he never feels any effort as soon as the action is initiated... But that doesn't mean things are the same as before action is initiated...



GregP said:


> 6.	A 10,000 pound airplane at 3g needs 30,000 pounds of lift to fly at 3 g, not 54,000. Any added lift from the propeller thrust just decreases the amount of lift the wing needs to produce. 3g – 3g. In Algebra, the “=“ sign means EQUALS. 30,000 pounds does not equal 54,000 pounds … it equals 30,000 pounds. The real only “extra lift” needed is to counteract the tail downforce. So the 30,000 pounds turns into a bit more in a conventional wing-first aircraft and bit less in a canard aircraft (because the forward tail lifts upward instead of downward) but not an extra 24,000 pounds.



You would know that *if* you knew how much the wings actually bend in flight, but you don't. Hence my inquiry about methods to find that out with strain gages, full scale in case the effect is not scaleable, and matched to static values with wings bent on the ground to evaluate the extent of the actual bending in flight... All of which we now seem to agree was never done on WWII fighters (except for the static on-the-ground part).



GregP said:


> 7.	There is no void created above the wing; the center of lift doesn’t shift since the local airflow is not either transonic or supersonic.



I agree this would seem unlikely to persist for more than a micro-second, but then nobody realizes these nose-pulled types might begin to pivot at the nose (not the same as pivoting within the wing's chord), and the effect might be observable only in turning flight with assymetrical incoming air...



GregP said:


> 8.	Your theories are so far off from the aerodynamic formulas that produced the actual aircraft as to be out of the ballpark ... they're craptacular, to quote Bart Simpson. Gaston, the WWII fighters FLEW AS DESIGNED, meaning the designers knew what they were doing and their formulas were correct. As I said before, you need to take a course in aerodynamics, not try to reinvent the science.



Sorry I could not plant the seed of doubt in your mind... 

Flight physics say the Me-109G out-turns, in multiple consecutive sustained slow speed level turns, an early slightly underpowered needle-tip prop P-47D Razorback.

The reason they say that is because they are ****.

Cheers,

Gaston


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## mhuxt (Mar 30, 2012)

Now, that's some hubris right there.


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## Elmas (Mar 30, 2012)

Years ago a very important Maths magazine received from an Italian University some papers with extremely difficult formulas, something written in this way







The magazine published all the papers ....that of course were completely false.
( those above are true: they are the solutions of differential equations, very important in aerodynamics).

.... the signature of the Author was " ***** *******" someting like, in English.......... "En*ous Bu***t"......


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## wuzak (Mar 30, 2012)

If it isn't scaleable then it probably isn't true.

For scale testing you need to do some of this:
Dimensional analysis

Aerodynamicists have been using this for many years since it isn't always practical to test full size aircraft. Using Dimensional analysis the aerodynamicist can figure out what scale model to use and what wind speeds to test.

I think you would also need to do the same for structural strength, since you seem to be worried about deflections.

Wind tunnel testing should also be more repeatable than flight testing - scale or full size.

So Gaston, how good are you at maths?


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## Jenisch (Mar 30, 2012)

I don't know what genius like Gaston are always doing discussing in the internet when they can revolutionize their fields.


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## FLYBOYJ (Mar 30, 2012)

Gaston said:


> Imagine the vertical height of the prop, then put the micro-second initial pivot point at the bottom 20% height... If you increase AoA, the top of the prop by definition moves back compared to the trajectory, but here it does so for a micro second by dipping the CL and pivoting *within* the prop's face...


 And did you ever consider that the prop bends too?



Gaston said:


> You would know that *if* you knew how much the wings actually bend in flight, but you don't. Hence my inquiry about methods to find that out with strain gages, full scale in case the effect is not scaleable, and matched to static values with wings bent on the ground to evaluate the extent of the actual bending in flight... All of which we now seem to agree was never done on WWII fighters (except for the static on-the-ground part).


While strain gauges did a lot to enhance gaining in flight stress information one could calculate very accurately the amont of bend a wing would experience in flight based on static testing. Strain gauges provided a reality check of what was calculated. Strain gauges in the bigger picture is a tool used for fatigue calculations rather than load testing. Read about Anne Burns and her work on the de Havilland Comet.

I still see a lot of hot air rising...


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## Shortround6 (Mar 30, 2012)

I believe there was also a lot photography work done, both movies and stills, of wings both on aircraft in flight and in wind tunnels. Wind tunnels used both the wool tuft and smoke to study air patterns while in flight tests used the wool tuft. 
Some aircraft were tested with different airfoil sections on parts of the wing. I would think that somebody might have noticed if the lift,drag and airflow in all these experiments didn't go along with the calculated values. Or if it didn't that th e calculations were sometimes modified.


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## FLYBOYJ (Mar 30, 2012)

Shortround6 said:


> I believe there was also a lot photography work done, both movies and stills, of wings both on aircraft in flight and in wind tunnels. Wind tunnels used both the wool tuft and smoke to study air patterns while in flight tests used the wool tuft.
> Some aircraft were tested with different airfoil sections on parts of the wing. I would think that somebody might have noticed if the lift,drag and airflow in all these experiments didn't go along with the calculated values. Or if it didn't that th e calculations were sometimes modified.



Spot on


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## davparlr (Mar 30, 2012)

An entertaining site if one doesn't try to make out the logic. Gaston's post logic, or lack of, kind of remind me of a little puzzle my Dad us to say, "if it took a hen and a half a day and a half to lay an egg and a half , how long would it take a grasshopper with boots on to kick the seeds out of a dill pickle?". I never came up with an answer.

In reality, aerodynamics is a complex issue with multiple factors inter-playing. Many analysis techniques simplifies the interaction with approximate algorithms and/or assumptions, e.g, airflow will be subsonic, or, air is an incompressible medium like water. Over time, these calculations have been proven very accurate by wind tunnels, flight test, and in actual performance. In addition, now days, powerful computers can iron out even the slight variances to the point that performance rarely vary from the calculated data as verified in rigorous flight test. It is typical now that aircraft now behave as the simulators predict. To think this isn't so is as irrational as trying to predict how long it is going to take that grasshopper to kick those seeds.


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## wuzak (Mar 30, 2012)

FLYBOYJ said:


> And did you ever consider that the prop bends too?



And prop shafts, engines, engine mounts, fusealges, etc.


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## GregP (Mar 30, 2012)

One point, Gaston. You seem to think the top of the prop arc moves backwards when the aircraft pitches up.

In reality, the aircraft is moving through the air very fast and all that happens is the top of the prop arc moves infintessimally slower forward than the bottom of the prop arc does. The only time the top of the prop arc will move backward is when the aircraft is a model in a wind tunnel which is stationary and the the model pitches up. That action is not scalable since the real aircraft is moving forward WAY too fast for the top of the prop arc to actually move backward. Rate of pitch is nowhere NEAR fast enough, even in a Pitt's Special or an Edge 540.

Please don't reply with some other part of your theory; your theory is wrong. When you are the only one who thinks something is possible, then there are only two possibilities. Either everyone else is wrong and you are the genius ... or the everyone else is right and you are mistaken. In this cases, since the airplanes fly as designed by people using conventional aerodynamic principles, you are most probably the one who is wrong in all reasonableness. Think about it. If the planes fly as designed, where are the aerodynamic formulas used to design them wrong when they depart from your theories? Hey, the WWII fighters fly very well ... when the fan in front is turning. When the fan stops, they descend remarkably well and remarkably quickly.

Keep in mind ... One out of every four people is crazy. Think of your three best friends ... if they're OK ... it's you.

And it doesn't matter if the wing bends within the design envelope ... it is designed to do that. All that matters is if the wing is overstressed to the point of plastic deformation or failure. If that happens, the formulas are not important ... the aircraft is damaged or has failed and it's nylon letdown time or time for a CAREFUL landing at low speed.


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## Jenisch (Mar 31, 2012)

Hey Gaston, if you come to Brazil someday, contact me, I can take you to my flight school to you discuss with the intructors your theories. Then we can take you to a flight in order to you prove then. LOL!


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## Gaston (Apr 1, 2012)

Shortround6 said:


> I believe there was also a lot photography work done, both movies and stills, of wings both on aircraft in flight and in wind tunnels. Wind tunnels used both the wool tuft and smoke to study air patterns while in flight tests used the wool tuft.
> Some aircraft were tested with different airfoil sections on parts of the wing. I would think that somebody might have noticed if the lift,drag and airflow in all these experiments didn't go along with the calculated values. Or if it didn't that th e calculations were sometimes modified.



I did consider the implications for the extra wing bending causing extra drag: That puzzled me.

But there are two ways this could have escaped detection: First, if the effect in a turn has the same extent accross the board on all similar types, where is your reference point to know that extra drag is extra drag?

Yes they can calculate thrust to drag *in a straight line*, but my theory isn't about straight lines...

Second, propeller aircrafts have better low speed acceleration than comparable power contemporary jets: That is why steam catapults are essential to jets on aircraft carriers. This means that at low speeds, propeller aircrafts have more useable excess power to counter the drag, and in my theory reducing the power also reduces the wing bending, so it reduces the drag. But if you increase the power, then the prop's acceleration has a lot reserve to take on the drag compared to a jet.

You can see the effect on a jet of similar power and near-identical wingloading to a late Griffon Spitfire: The Vampire.

Quote: "The maximum speed obtainable with a Goblin II engine giving 3,000 lb. sea-level static thrust is 528 m.p.h. at 20,000 ft."

So that is less thrust than a 1800 hp prop fighter, and the 1946 Griffon Mk XIV Spits had much more than that, maybe they could even do +25 lbs by then...

In theory, in low speed sustained turns, the Vampire *has even less power available because of lower incoming air intake speed*, yet wingloading is nearly the same as a Mk XIV Spitfire: This means a Mk XIV Spitfire should out-turn it at low speeds, since it can apply full power in sustained turns, something which is robbed from the jet's intake by the turn-reduced speed...

What do you know: The Vampire out-turned the Mk XIV Griffon Spitfire in sustained turns in 1946, despite inferior acceleration:

Quote: "Just been reading Alfred Price's book Spitfire in combat and I have to say it is a lovely little potted reference work.

In it he detailed a performance evaluation between a Spitfire Mk XIV and a de Haviland Vampire Mk1. The Spit was superior only in initial acceleration, climb rate and apparently roll. Unsuprisingly the Vampire was superior in everything else but what did suprise me was that the Vampire could turn inside a Spitfire!"

Spitfire MkXIV vs Vampire 1 1946 - Key Publishing Ltd Aviation Forums


I am pretty sure the same thing would have turned up had any pusher-prop figther been extensively tested against a similar power-wingloading nose-pulled fighter: The fact that no such high-power pusher fighter ever saw extensive service is a clue as to why the disparity in nose-driven wingloading in sustained turns was never discovered...

As to the wing-flexing camera work during testing, look at it this way: US test conclusions is that the P-51B will get behind the P-47D needle-tip prop Razorback in 3-3.5turns... Russian tests conclude the same needle-tip P-47D Razorback is at 27 seconds, while they say the Bf-109G is at 22 seconds...

German tests conclude an underpowered needle-tip prop P-47D out-turns the Bf-109G: All combat accounts agree with them on multiple low-speed 360°s, *and no one here has presented here ONE counter-example of the contrary*. (I do know the later P-47D Bubbletop is not as good, and also that right or diving turns are comparatively not as good as well.)

For the early Razorback, either the Germans testers are dolts, or the US/Soviets testers are dolts: Make your choice!

Combat accounts indicates Allied testing procedures, in those days, were rather poor or even extremely poor at finding the unexpected, *despite better testing circumstances*... The US Navy tests of the FW-190As are particularly stupid in their conclusions, and indicate to me these people usually found exactly what they expected to find, which is not conducive to finding out something weird and unexpected... This is could extend to the camera work you mention, which was probably focussed on some specialized narrow purpose, a specific wing airfoil etc, not putting into question the sum of available knowledge...

Gaston


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## GregP (Apr 1, 2012)

Gaston,

One more time, wing bending doesn't matter unless you overstress the wing. if you don't overstress it, the bending is as designed and is taken into account in the performance predictions. You are living in a dream world of sharp-turning, needle-prop P-47's and slow-turning Me 109's, coupled with delusions of mathematical copmpetence. GO GET AN AERODYNAMICS TEXT. The dolt is not the Germans or the Soviets; it is ... well, you can fill in the blank.

You link above is not a link to a report; it is a link to a quote by Phil Foster ... who is Phil Foster? Nobody I recognize as a expert in anything.


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## Jenisch (Apr 1, 2012)

GregP said:


> Gaston,
> 
> You are living in a dream world of sharp-turning, needle-prop P-47's and slow-turning Me 109's, coupled with delusions of mathematical copmpetence. GO GET AN AERODYNAMICS TEXT. The dolt is not the Germans or the Soviets; it is ... well, you can fill in the blank.



Dear Greg, you are probably not aware, but Mr. Churchill made a radio pronuncement today, where he vitally stated the following: 

*We shall ignore trolls in France, we shall ignore trolls on the seas and oceans, we shall ignore trolls with growing confidence and growing strength in the air, we shall ignore trolls in our forums, whatever the cost may be.*


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## Jabberwocky (Apr 1, 2012)

Found an extract from the test - taken from a jet out turning a spitfire?



> "Turning Circles: The Vampire I is superior to the Spitfire XIV at all heights. The two aircraft were flown in line astern formation. The Spitfire was positioned on the Vampire's tail. Both aircraft tightened up to the minimum turning circle with maximum power. It became apparent that the Vampire was able to keep inside the Spitfire's turning circles. After four or five turns the Vampire was able to position itself on the Spitfire's tail so that the deflection shot was possible. The wing loading of the Vampire is 33.1lbs per sq. ft. compared with Spitfire XIV's 35.1 lbs per sq. ft.
> ...The Vampire will outmanoeuvre the Spitfire type of aircraft at all heights, except for initial acceleration at low speeds and in rolling.
> ... The Spifire XIV used in the comparison trial was a fully operational aircraft fitted with a Griffon 65, giving 2,015 h.p. at 7,500 ft. Vampire I had an operational take-off weight of 8,800 pounds, powered by a de Havilland Goblin 2 turbojet, developing 3,000 pounds static thrust."



Not really that surprising. Lower wing loading and more thrust, just like the flight text books would have it.


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## GregP (Apr 1, 2012)

Thanks Jenisch, I have tried reasonableness to no avail and give up on Gaston. He has a very good imagination and could probably write very good fiction without the science part. 

Like I said earlier, his theories are interesting even if wrong, but enough is enough, and I have had enough of them.


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## Gaston (Apr 1, 2012)

GregP said:


> One point, Gaston. You seem to think the top of the prop arc moves backwards when the aircraft pitches up.
> 
> In reality, the aircraft is moving through the air very fast and all that happens is the top of the prop arc moves infintessimally slower forward than the bottom of the prop arc does. The only time the top of the prop arc will move backward is when the aircraft is a model in a wind tunnel which is stationary and the the model pitches up. That action is not scalable since the real aircraft is moving forward WAY too fast for the top of the prop arc to actually move backward. Rate of pitch is nowhere NEAR fast enough, even in a Pitt's Special or an Edge 540..



The outer turn prop disc "half" (I put hyphens as it is just an illustrative term) is not accelerating during the initiation of the turn, so it is the inside turn prop disc half that is *decelerating*. It is thus pulled "back" compared to the trajectory, and where it would be along its path if the trajectory was straightened out, as it is difficult to compare a curved path to a straight line...

But the AoA has increased, which also means the prop is more off-center, if the curve was again averaged out to a straight line: Again, try lifting the one-side barbell straight up, or with that AoA slant: Big difference in effort to lift and maintain the equivalent to AoA "slant"... The longer the barbell handle the bigger the effort...

But on top of that, you must add that slower air is hitting one half of the prop vs the faster air on the other half, which means that, as you lift the barbell with a sideways AoA from the vertical, someone is slightly pushing sideways to *reduce* the AoA slant you try to maintain while lifting... And yet your hold is firm enough to nullify *completely* that sideway effort: That is a large achievement, with a correspondingly large counter-acting force implied.




GregP said:


> Please don't reply with some other part of your theory; your theory is wrong. When you are the only one who thinks something is possible, then there are only two possibilities. Either everyone else is wrong and you are the genius ... or the everyone else is right and you are mistaken. In this cases, since the airplanes fly as designed by people using conventional aerodynamic principles, you are most probably the one who is wrong in all reasonableness. Think about it. If the planes fly as designed, where are the aerodynamic formulas used to design them wrong when they depart from your theories?



This is a classic authority argument.

Second, if WWII fighter airframes are typically designed for a safety factor of two (12-14 Gs before deformation, vs 6-7 Gs of safe use), there is plenty of room for my theory to be correct if the safety factor was unknowingly narrower than assumed.

Third, I am not the one ignoring significant test evidence (but truly overwhelming amounts of pilot accounts) that clearly shows the flight physics is completely wrong for these particular types of nose-pulled aircrafts...

For instance, no one has explained to me how an experienced 28 kill Me-109G ace could claim (not an exact quote, but accurate in substance): *"Optimum sustained turning speed for the Me-109G-6 is around 250 km/h with the throttle reduced."* In other words, barely 50-55 mph above stall...

Fourth, all the valid arguments that could have, at a stroke, destroyed my theory, turn out to be precisely what is missing from the evidence record:

1- Wing bending data while in turning flight, compared at various throttle settings, is not available for these type of old fighters (so far).

2- Pusher-prop aircrafts with similar characteristics were never available for extended combats or comparisons.

And then of course, probably the closest thing to a pusher prop WWII fighter that WAS used for a comparison, the Vampire Mk I, turns out unexpectedly to out-turn a Spitfire in sustained turns despite having less power, inferior acceleration and an inferior climb rate... 

Maybe the wing bending data will prove me wrong in the end, but I have to say, from my point of view, I can't be impressed with points of view that won't even address the fact that the contradictions, from believable sources, are TOTAL.

IE: Tsagi: P-47D (Razorback needle prop): 27 seconds, Me-109G: 21-22 seconds *VS* "The P-47D (Razorback needle prop) out-turns our Bf-109G" (KG 200)

Or: US Navy test (paraphrasing): "This is mainly an interceptor best used in vertical combat" *VS* "Red Fleet" 1943 article on a concensus of observed combat behaviour: "The FW-190A will inevitably offer turning combat at a minimum speed"

Like I said, either one or the other is a complete dolt: The fact that these contradictions were not even really noticed, and never before even discussed in those particular counter-intuitive terms, says more about the usual consensus than about me...

Gaston

P.S: And for that minor 33 vs 35 wingloading value difference, do you know how large a turn difference is the Vampire reversing a tail position in FOUR 360° turns?: It means a gain of + 90° for every 360°.... That is pretty large for an aircraft with much less power... G.


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## Shortround6 (Apr 1, 2012)

Gaston, 

the very idea that the Vampire had less power than the Spitfire just shows how far from reality you really are. 

try figuring out how thrust and power work in a straight line and in a straight climb before trying to figure out turns.


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## tyrodtom (Apr 1, 2012)

You keep saying the Vampire had less power, absolutely incorrect. A pound of thrust is equal to more than 1 horsepower at 400 knots or what ever speed this contest took place. The Vampire Mk I had 3300 lb of thrust, the Griffon powered Spitfire 1800 hp? The Vampire had more than twice as much power.

There's a formulae for converting pounds of thrust to horsepower, look it up Gas Ton.


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## FLYBOYJ (Apr 1, 2012)




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## DerAdlerIstGelandet (Apr 2, 2012)

I think we need one of those "...for Dummies" books.


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## Siegfried (Apr 2, 2012)

There are some formulae here that will help. For a Jet engine the equivalent power can be calculated as:
*P = F x v* (power = Force x velocity). The usnits are SI metric
*P* = Power in watts
*F* = Force in Newtons (approximetly 98 grams of thrust)
*v* = velocity in meters/sec

Loss in propellor efficiency needs to be considered.

The equivalent thrust of a prop aircraft can be calculated by rearranging

*F = P/v.*

The basic understanding that comes from this is that jet thrust remains constant irrespective of speed while the equivalent thrust a propellor aircraft can provide falls of inversely proportional to speed. 

Another result is that because drag increases with the square of velocity then cube root law applies to speed increase with prop aircraft.

To double speed in a prop aircraft would require a 8 fold increase in power.
To double speed in a jet aircraft would required a 4 fold increase in thrust.

Note that piston engined aircraft can have a lot of jet thrust, about 300lbs for a two stage Merlin 66. A Jumo 213E maybe 448lbs (about 200kg).

Technically thrust in engines is now declared in kP (kilopond) as KG is a unit of weight caused by gravity not a unit of force. On the earths surface 1KG produces 1KP of force.


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## FLYBOYJ (Apr 2, 2012)

Gaston said:


> The outer turn prop disc "half" (I put hyphens as it is just an illustrative term) is not accelerating during the initiation of the turn, so it is the inside turn prop disc half that is *decelerating*. It is thus pulled "back" compared to the trajectory, and where it would be along its path if the trajectory was straightened out, as it is difficult to compare a curved path to a straight line...


 And have you considered the prop is bending AND producing lift (thrust) while this is going on in your mind???


Gaston said:


> But the AoA has increased, which also means the prop is more off-center, if the curve was again averaged out to a straight line: Again, try lifting the one-side barbell straight up, or with that AoA slant: Big difference in effort to lift and maintain the equivalent to AoA "slant"... The longer the barbell handle the bigger the effort...
> 
> But on top of that, you must add that slower air is hitting one half of the prop vs the faster air on the other half, which means that, as you lift the barbell with a sideways AoA from the vertical, someone is slightly pushing sideways to *reduce* the AoA slant you try to maintain while lifting... And yet your hold is firm enough to nullify *completely* that sideway effort: That is a large achievement, with a correspondingly large counter-acting force implied.


And you base this comment of yours on ????





Gaston said:


> This is a classic authority argument.
> 
> Second, if WWII fighter airframes are typically designed for a safety factor of two (12-14 Gs before deformation, vs 6-7 Gs of safe use), there is plenty of room for my theory to be correct if the safety factor was unknowingly narrower than assumed.
> 
> ...



Is it because you fail to relize that stall speed INCREASES with bank angle???? At what bank angle??????



Gaston said:


> Fourth, all the valid arguments that could have, at a stroke, destroyed my theory, turn out to be precisely what is missing from the evidence record:
> 
> 1- Wing bending data while in turning flight, compared at various throttle settings, is not available for these type of old fighters (so far).
> 
> ...



My god, there is so much jibberish there I don't know where to start!


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## Jenisch (Apr 2, 2012)

Shortround6 said:


> Gaston,
> 
> the very idea that the Vampire had less power than the Spitfire just shows how far from reality you really are.


 



]


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## drgondog (Apr 2, 2012)

quit feeding the troll - it's bad for (your) digestion.

You really have to give him a hand. How many guys have drawn so many knowledgable members of this forum down ratholes with his talented but unmitigated bovine fecal matter? 

Each of us has been introduced to more mangled terminology than even the late great jimmy Durante, Casey Stengle or Yogi Berra were able to collect over 50 years.


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## GregP (Apr 2, 2012)

Spot on Drgondog, and at just the right prop-to-tail ratio! Can't help it, that one just cracks me up!


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## FLYBOYJ (Apr 2, 2012)

Prop to Tail Ratio - the ratio between the diameter of a propeller when compared to the size of the tail. This measurement includes the tail wheel as it sits in on a dirt strip that has just had a smooth layer of cow manure spread over the measuring area.


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## GregP (Apr 2, 2012)

You can only spread the manure if the rear end moves backwards momentarily and the if the center of crap drops for a microsecond to become craptacular.


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## wuzak (Apr 2, 2012)

Surely the CoC (centre of crap) has to collapse for a micorsecond, with the loading on the wings by multipled by a factor of 3 due to the prop to tail ratio, the wing deflections cauing microgaps in the panels so that as the turn tightens the crap gets squeezed out?


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## GregP (Apr 2, 2012)

Laxitivly explained at last, Eureka! There might be some BENDING involved somewhere ... but I digress.


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## Gaston (Apr 5, 2012)

Jabberwocky said:


> Found an extract from the test - taken from a jet out turning a spitfire?
> 
> 
> 
> Not really that surprising. Lower wing loading and more thrust, just like the flight text books would have it.



But didn't GregP just say 1800 hp on a prop is like a maximum of 3307 pounds of static thrust at the peak relevant speed? 2000 hp on a Spitfire would be over 3600 lbs of static thrust while sustaining turns, vs 3000 lbs on the Vampire... 

This is obviously confirmed, you would think, by the heavier weight of the Spitfire climbing faster, from likely a much lower peak sustained climbing speed, than the Vampire...

If a heavier much more draggy aircraft, with a higher wingloading, climbs faster than a lighter sleeker aircraft, and this means the heavier aircraft has *less* thrust *at the relevant peak climb speeds* (which are also likely pretty close to peak turn speeds at full power), you'll have to run that one by me in detail... 

And if the difference in wingloading between the Vampire and Spitfire (33 lbs vs 35 lbs, of which what is made of it is just laughable) amounts to around 6%, how does that confirm a proven gaining of 25% per turn to reverse a tailing Spitfire position in four turns? This means the Spit XIV, probably going at 20 seconds for each 360° turn, is hugely slower-turning than the Vampire, which for its part was inevitably completing them in around 15 seconds to gain one full 360° turn in only *four* full 360° turns...

And all of you failed to mention that the most significant discrepancy between the two was likely the drag, not the thrust, especially the engine cooling drag, which is why a pusher prop fighter would have been a much more relevant comparison... Let me chalk you up with a big fat fail on that while I am at it...

Gaston


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## Gaston (Apr 5, 2012)

tyrodtom said:


> You keep saying the Vampire had less power, absolutely incorrect. A pound of thrust is equal to more than 1 horsepower at 400 knots or what ever speed this contest took place. The Vampire Mk I had 3300 lb of thrust, the Griffon powered Spitfire 1800 hp? The Vampire had more than twice as much power.
> 
> There's a formulae for converting pounds of thrust to horsepower, look it up Gas Ton.



And where did you get the grotesque idea the Spitfire could sustain its tightest possible turns at 400 knots?:

Quote: ""Turning Circles: The Vampire I is superior to the Spitfire XIV at all heights. The two aircraft were flown in line astern formation. The Spitfire was positioned on the Vampire's tail. Both aircraft tightened up to *the minimum turning circle* with maximum power. It became apparent that the Vampire was able to keep inside the Spitfire's turning circles. After four or five turns the Vampire was able to position itself on the Spitfire's tail so that the deflection shot was possible."

*Besides, from lower speeds, with more weight, a higher wingloading and much more drag, the Spitfire is acknowledged to climb faster: Surely your great science can tell me how that means less total thrust?*

Besides, if you HAD looked it up, you would know there is no straightforward answer: Here is an interesting post that shows the effect of speed, the 270 mph of the Lancaster being the more relevant speed to the Spitfire/Vampire turn contest at minimum radius:

Propeller Thrust Figures [Archive] - PPRuNe Forums

Quote: "Okay so you're talking about thrust-to-weight, thrust-to-drag, and lift-to-drag figuresNo, thrust versus horse power.

For example, the Mosquito I is quoted as having a maximum speed in the order of 370MPH, and the Lancaster I about 270MPH, both using the same engine giving 1,280 horse power. Given the paucity of exact figures these are ball park and will do for illustration.

Using the formula thrust=horse power*375/velocity

Mosquito thrust=1280*375/370 = 1,297 pounds/engine

Lancaster thrust=1280*375/270 = 1,778 pounds/engine"

Since it is not 1280 hp on the Spitfire Mk XIV going in circles at 270 mph or less, but more like 2000 hp or more post-war, if not more, the figure is around 3000 lbs, close to what GregP mentionned...

And again a big fat fail on the issue of drag, obviously more relevant....

Gaston


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## GregP (Apr 5, 2012)

Gaston, at this time nobody cares what you post, nor will they argue with you anymore until you BUY AN AERODYNAMICS TEXT and READ IT.

When you do, please come back and talk with us.

Hope I didn't overstep my bounds there ... FlyboyJ. If I did, mea culpa and I'll refrian from posting to our buddy Gaston entirely going forward.

FlyboyJ, the Chino airshow is May 5-6. Will you make it? If so, can we get together on Friday, May 4?


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## Jabberwocky (Apr 5, 2012)

A Griffon 65 had a hair under/over 2000 hp, depending on conditions. Going by the figures you provided (thrust=horse power*375/velocity), then the Spitfire XIV has 2000*375/448 = 1,674 pounds/engine.... can you tell me, is this figure less or more than 3,000 lbs static thrust?

Of course, for a supercharged internal combustion aero engine, power depends on greatly on altitude. At 0 feet the Griffon made 1850 hp and at 18,000 ft it made 1650 hp. Those are pretty big variations in thrust.

All other sorts of things come into account when considering rate of climb. Like, specific excess thrust, L/D and prop reduction ratios. Look at this: http://www.spitfireperformance.com/spit14climb-level.jpg. Different reduction ratios produced a minimal difference in speed, but a 10-12% difference in rate of climb. 

The Lancaster/Mosquito I example you bring up also completely ignores the fact that the Lancaster I reached its top speed at about 17,000 ft in early versions (Merlin 22 at +9 lbs) and about 11,500 feet with the later versions (Merlin 224 at +16 lbs). At similar boost levels, the Mosquito Mk IV reached its top speed at about 22,500 ft (Merlin 21 at +9 lbs) and about 16,500-17,000 ft when the Merlin 21 was cleared for +14 and +16 lbs boost.

Do you think that makes a difference?


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## FLYBOYJ (Apr 5, 2012)

GregP said:


> Hope I didn't overstep my bounds there ... FlyboyJ. If I did, mea culpa and I'll refrian from posting to our buddy Gaston entirely going forward.
> 
> FlyboyJ, the Chino airshow is May 5-6. Will you make it? If so, can we get together on Friday, May 4?


No worries Greg! No, not planning on making Chino although I will be in California. If the opportunity presents itself? Let's keep in touch!


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## FLYBOYJ (Apr 5, 2012)

Gaston said:


> engine cooling drag


And this is defined and measured how?


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## kettbo (Aug 21, 2014)

I am away from some of my books
What was the weight penalty for a MW-50 set-up?
Weight of a mid 1943 Bf-109G6 compared to an August 1944 Bf-109G14 should work


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