Please correct the P40b!

P36/Hawk 75 had nothing to do with P40 - these 2 were totally different aircraft. Most pilots remember p36/hawk 75 as an extremely maneuverable and easy to handle fighter - exact opposite to P40b. I suggest to read the comparison in Gabresky's book - he flew both of them (then the comparison of p40 to spit9... )

 

Well, typical Axis whine, In real life, the P40B, at lower alt was, by historical accouts, every bit a competive plane as a 109e. And in the hands of experianced pilot, it could prove to be hand full for any 109E pilot.

In fact it could out turn and out run it. see link for some stories and specifcations on the P40b

http://www.danford.net/p040.htm
http://home.att.net/~jbaugher1/p40_6.html

 

slats are slats! engine, aerodynamics, weight, all influence as well

 

Hi Stec,

The tenth prototype of P36 became the first P40. It differed from other P36s ONLY by inline engine, otherwise it was COMPLETELY the same.

R.L. Scott and his fellow pilots never bitched about their P40s, in fact they loved them (take into account that the AVG fought much more manouverable opponents than Bf109s).

Hi Nicae,

you are, of course, right. But we are talking about very similar powerplants (1175 vs 1030 HP) and similar size of frontal areas. The Me109 had higher wingloading, but greater top speed. In aerodynamics everything is a tradeoff between lift and drag. If you have thin wing with smaller area, you have less drag but also less lift. Greater wing area: more lift (good), but more drag also (not so good)...

 

Update about i153/i16...
grr....

Climb indicator in cocpit for i16/i153 was incorrectly marked... again...
Climbs speeds are 'normal'
for example i153 have not 25m/s but a ~14m/s only.
In future i must warn you to check all stats by .showdata.

 

Muttdog, here captions from your link www.danford.net

"It was vilified by many as being too slow, lacking in maneuverability, having too low a climbing rate, and being largely obsolescent by contemporary world standards even before it was placed in production. The inadequacies of the P-40 were even the subject of a Congressional investigation. It gets regularly included on lists of the worst combat aircraft of World War 2."

"The P-40B (Model H81B) differed from the P-40 in having an extra 0.30-inch machine gun in each wing. The engine was still the V-1710-33. In September 1940, 131 P-40Bs were procured by the Army to replace the deferred P-40s. Serials were 41-5205/5304 and 41-13297/13327. The first P-40B flew on March 13, 1941. The P-40B retained the same dimensions of the P-40, but weight was increased to 5590 pounds empty, 7326 pounds gross, and 7600 pounds maximum loaded. Because of the additional weight, the P-40B had an inferior performance to the P-40, maximum speed being 352 mph, service ceiling being 32,400 feet, and initial climb rate being 2860 feet per minute. Normal range was 730 miles, but a maximum range of 1230 miles could be attained at the minimum cruise settings."

"However, Britain quickly concluded that these planes were not suitable for combat, since they lacked armor protection for the pilot, armor-glass windshields, or self-sealing fuel tanks. Nevertheless, since a German invasion was feared to be imminent, they were actually issued to several operational squadrons. "

 

quote from
encyclopedia of world aricraft

thought the next 3 years ((40-43)) curtiss made tremendous efforts to iprove capbilities of the p40 rusulting of a number of variants, Despite all there efforts, which resulted in quite an impvoment, it left performance far far below that of conteporay allied and axis fighters and production ended in december 44

 

http://www.zap16.com/mil fact/curtiss p-40 warhawk.htm

The P-40 series was in no way a very special fighter but was a more than average fighter-bomber, just two other US fighters were build in larger numbers the Republic P-47 Thunderbolt and the North American P-51 Mustang.



The base for the P-40 series was model 751, a model 75/XP-37A airframe was adjusted for the Allison V-1710-11 Line-engine (858 kW) and it became the first American fighter witch flew at a constant height at a speed of more than 483 Kph. (300 miles).



The type was bought by the US Army Air Corps under the name P-40 with a less powerful V-1710-33 engine.

Export versions where the Hawk 81-A1 for France, and the Tomahawk Mk I for the United Kingdom.



Improved models were:

P-40B (Tomahawk Mk IIA): with self closing fuel tanks, armor and better weaponry.

P-40C (Tomahawk Mk IIB): with improved self closing fuel tanks, and two extra machineguns in the wings.

P-40D (Kittyhawk Mk I): powered by the V-1710-39 engine (858 kW) with improved turbo to keep up performance at higher altitudes.

P-40E: With 4 wing machineguns

Kittyhawk Mk IA: Identical to the P-40E only 6x wing machineguns

P-40F / P-40L (Kittyhawk Mk II): New Packard V-1650-1 engine (969) an American build Rolls-Royce Merlin



The greatest power of the P-40 was the performance as fighter-bomber at low altitude and further developments were:

P-40K (Kittyhawk Mk III): P-40E with V-1710-33 engine

P-40M: with the V-1710-71 engine

and the final P-40N (Kittyhawk Mk IV): with V-1710-81/99/115 engine and alterations to decrease weight for improvement of performance.

 

http://www.accessweb.com/users/mconstab/kitty.htm

The Curtiss-Wright Corporation started designing a single-wing, fighter aircraft with radial engine, retractable landing gear and all-metal construction in 1934. The resulting aircraft they dubbed the Hawk 75 and the American military called it the P-36 Mohawk. By 1937, over 1,300 had been delivered when the Curtiss-Wright Corporation decided to make a major modification by installing an Allison liquid-cooled engine. This alteration was successful and started a long series of models, the first named the P-40 Warhawk by the Americans. The rest of the aircraft was essentially unchanged from the P-36.
By 1940, the RAF was accepting delivery of the new aircraft that they called the Tomahawk I. In comparison with the Messerschmitt Me-109 or the Supermarine Spitfire V it was decidedly inferior except in manouverability at low altitudes and having a tough construction. The Tomahawk was used in Britain as a trainer and an army cooperation aircraft. It was sent to the Orient, India and North Africa to augment the Hawker Hurricanes. This was the common solution to inferior aircraft, even if the Japanese, Germans and Italians were flying better fighters. The RAF, Royal Australian Air Force and the South African Air Force flew them as ground-attack aircraft in support of the 8th Army in North Africa. Unfortunately, for many pilots they were also forced to use this inferior aircraft as an escort fighter for light and medium bombers against Me-109s and Maachi 202s. It showed up badly against both aircraft, with a high loss rate. The P-40D, named the Kittyhawk I by the English and the Warhawk by the Americans, had an improved Allison engine that allowed for a shorter nose and had the fusilage mounted 0.50 caliber machine guns moved to the wings to allow for a hefty six 50 caliber machine guns that would become the standard suite of armament for all American fighters. A Packard Merlin-engined version was produced for export to Russia, but no models were received by the English, Australian or South African squadrons flying the Kittyhawk. Many versions of the aircraft were developed all in an attempt to improve the performance of the inadequate Allison engines (the one pictured above is a P-40M). None of the modifications made up for this engine's lack of power. Overall, the various models of the P-40 made it the second most numerous fighter aircraft produced by the Allies during WWII. They had a production run of some 13,738.

Technical Details
All major variants of the P-40 series were single-seat fighter or fighter-bomber aircraft. They came in a confusing series of engine modifications, and gun arrangements with even minor variations given a letter designation where it likely wasn't warranted.

The P-40C was a major variant called the Tomahawk II by the RAF. It mounted a 1,040 hp Allison V1710-3 v 12 liquid cooled engine. This engine generated a maximum speed of 345 mph (555 km/h), although under desert conditions with a sand filter over the air inlet it was considerably less. It was not usually equipped with oxygen so it's maximum altitude of 30,000 ft could not be reached by most pilots and it was typically flown at under 15,000 ft. It's range with internal fuel was 730 miles (1175 km). The Tomahawk II had two 0.303 machine guns on the cowl and four in the wings. It did not have the ability to carry bombs.

The P-40F, called the Kittyhawk II (also the Goshawk) was a major improvement in handling, although more power was not available. The ones shipped to Russia were equipped with the Packard built 1,300 hp V-1615-1 Rolls-Royce Merlin engine. All others used an Allison engine. This boosted the maximum airspeed to 364 mph (582 km/h). Range was 610 miles (976 km).The Kittyhawks had a major modification in their armaments, with the cowl-mounted machine guns removed and all guns upgraded to six 50 caliber machine guns in the wings. It could also carry a 500 lb bomb or a long-range fuel tank on the center-line, and 250 lbs of bombs under each wing (6 lb and 40 lb anti-personnel bomb clusters were also carried in North Africa).

 

Like it or not, the USAAF had only the P-40 available when it went to war. It rarely outperformed the fighters that it opposed, but it was one of the sturdiest fighters produced during World War II. Remembered as a "best second choice," innumerable pilots owe their lives to its rugged quality.
The American pilots had underestimated the maneuverability of the lightly built Japanese Zero fighters, and failed to utilize their superior speed and diving ability to advantage. It was soon the cardinal rule that a P-40 should always avoid mixing it individually with a Japanese fighter, owing to the Curtiss machine's inferior climb rate and maneuverability, but the P-40 substantiated a reputation for ruggedness that it was already acquiring with the RAF in the Middle East, and its armor protection saved many AVG pilots in subsequent combat.


http://216.219.216.110/curtiss/p40.html


The story of the Curtiss P-40 is a curious one indeed. Before the first one rolled off the assembly line it was considered obsolete by world standards. Yet it was in production until 1944 and saw service through the end of the war. 13,738 were built, more than any other type of U.S fighter except the Mustang and P-47.

The Curtiss P-40 was a poor performer and is often named as one of the worst fighters of WWII. It was however, available in the early days of the war when not much else was. It was also sturdy and could withstand a considerable amount of punishment. It was so adaptatable that one American Volunteer Group pilot remarked "if you added a periscope you could use it as a submarine."
The P-40, like the P-39, was a result of the wrong-headed military doctrine of "ascendancy of bombardment over pursuit" which was dominant in 1937 in the Army when the P-40 first appeared. This doctrine assumed that the prospect of high-altitude enemy air attack on the US was extremely remote. It was also believed that bomber technology was advancing so fast that fighter planes would soon be useless against them. For example, the B-17 could fly about 50 mph faster than the standard Army fighter at the time, the P-36. Coastal defense and ground attack in the defense of US territory were seen as the main tasks for any future fighter aircraft. Low-altitude performance and rugged construction received priority over high-altitude capabilities. As a result, until July 1943 fully half of all USAAF fighters were either P-39s or P-40s. However, by July 1945 only one P-40 group remained operational.

Early combat operations pointed to the need for more armor and self-sealing fuel tanks, which were included in the P-40B (called the Tomahawk Mk IIA in the UK). These improvements came at price: a significant loss of performance due to the extra weight. Further armor additions and fuel tank improvements added even more weight in the P-40C (Tomahawk Mk IIB). Curtiss addressed the airplane's mounting performance problems with the introduction of the P-40D (Kittyhawk Mk I), which was powered by a more powerful version of the Allison V-1710 engine, and had two additional wing-mounted guns. The engine change resulted in a slightly different external appearance, which was the reason the RAF renamed it from the Tomahawk to the Kittyhawk. Later, two more guns were added in the P-40E (Kittyhawk Mk IA), and this version was used with great success by General Claire Chenault's American Volunteer Group (The Flying Tigers) in China.

http://www.kotfsc.com/aircraft/warhawk.htm

that all I could find

 

Hi Devill,

>So Hohun, imagine that you suddenly get more lift on one wing and no lift on the other; then you go spinin'. That was what happened when slats were assymetricly deployed. Assymetric deployment of slats on Me109s was NOT intended, in fact it was dangerous.

Nonsense.

A spin happens if only one wing stalls because the airflow over the wings is asymmetric. Each slat individually deploys when the wing it's on is about to stall - even under asymmetric flight conditions. The asymmetric slat extension actually prevents a spin where an aircraft without slats would go down spinning.

When the Me 109 was developed, there was some doubt about the spinning characteristics with flaps deployed, and a mechanism for locking them down was incorporated. Then spinning trials with a recovery chute equipped Me 109 were conducted with slats free, and it was found to be much superior to slats locked and in fact almost spin-proof and very easy to recover. After that, the lock-down mechanism was abandoned.

Automatic slats became a feature of many later combat aircraft, like the Lavochkin series of fighters, the Me 262, the F-86, the A-4 and the F-4, just to name a few.

>Hohun, if Spit didn't have slats, how was he a better turner than bf109 then??? Let me tell you: for thesame reason it was slower... The answer is: the wing.

Don't believe the P-40 is an American Spitfire - it weighs 30% more at the same power, and that's is a large difference.

Regards,

Henning (HoHun)

 

Hohun,

What you just reffered to as "nonsense", came out from Mike Spick's book, and was confirmed as true by my college professor (teaches aerodynamic constructions at my university). So i guess you know more about planes than both of them together. WTG!


"Don't believe the P-40 is an American Spitfire - it weighs 30% more at the same power, and that's is a large difference."

Fine, but I was talking about Spit...
Anyways, thrust-to-weight ratio blessed bf109 with much better acceleration and climb, but simply its wing wasn't optimized for tighter turns. Less relative thickness (of the wing) means flatter airfoil curve, meaning less lift, at the cost of greater speed(less drag).

 

I have read that 109e's asymmetrical deployment of slats used to mess up aim in low speed turns and this was cured by redesigned slats in 109f.

 

AFAIK German pilots in fight sometimes pulled hard for a moment to pop-open both slats at a time. Extra lift during manoeuvering was always in handy and asymetrical opening of those messed up aim (as illo wrote) and in some situations it could cause at least slightly annoying roll if not something worse...

Btw, slats on Bf109 always were fully deployed or fully retracted. They popped in or popped out depending on pressure on leading edge of wing and never were half-open.

 

Slats out won´t give you immediatly more lift. They ALLOW you to pull higher AoA, thus more lift, but don´t give you immediatly more lift.
Actually slats are used to keep up lift in the aileron section, so you can keep control while the inner section of the wing begins to stall. You could also use a lot of washout, but this would mean instead of increasing lift decreasing total lift.
This is the reason why slats aren´t build over the whole wing. This would allow you much more lift, but the inner wing would stall now maybe later than the outer section, resulting in a very harsh stall characteristics. For a gentle stall characteristics you always need that the inner or middle section stall before the aileron sections stalls. Swept back wings perform somewhat different btw.

Actually it also happened that 109 turned into spits. The reason: The wing of the 109 was superior. Slats allowed them to fly at very high AoA, higher AR and so on. Spits actually have a wing with a significant lower thickness than many other WW2 fighter aircraft. What thickness was used for the P40 btw?
Spits turned also into 109, of course, but don´t forget that spits had way better power to weight ratio than P40. You also need power to pull you around in turns.


niklas

 

if you asc for my opinion the moust significant factor for horisontal turns is a wingloading.
Slats are very helpful in inreasing critical angle of attack, but they cant help then wingloads are differ too much.

 

What's AR?




And Hohun, no I don't have any real life stats about the turn performance of the P-40B. But let's look at the P-40B's and the 109E's data.

Code:

                                       [b]P-40B                         Bf-109E[/b]
engine power      :        1150 HP                            1100 HP
wing area            :        21.92 m^2                        16.17 m^2 
empty mass         :        2636 kg                            1900 kg
max takeoff mass:        3655 kg                            2665 kg
wing loading        :        166.7 kg/m^2                  164.8 kg/m^2
power loading     :        3.18 kg/HP                        2.42 kg/HP

The 109 does have a significant power loading advantage over the P-40 (and it shows in the game), but in terms of wing loading the difference is very marginal at best. They are close enough together so that it comes down to aerodynamics (drag under medium AOA's and so on). AFAIK the P-40 was the most maneuverable of the US fighters or at least one of the most maneuverable US fighters.


P.S. I used each plane's max takeoff weight to get its power and wing loading since I don't have their normal operating weights.

 

This is not true. First, where does wingloading come from? Minimum turn RADIUS is a function of lift to weight. lift is a function of wingarea, liftcoefficient, speed, density.
How fast you fly this radius is a function of drag and power

So if you reduce turning capabillities down to wingloading only, you neglect maximum liftcoefficient (slats...), and you assume same aircraft speed (hardly true, drag and power were too different)

Comparing wingload is rough estimation, assuming everything else being equal - but this wasn´t the case. Lift is a linear function of wingarea AND liftcoefficient.

I just checked the airfoils:
aircraft --------------------- wingroot--------tip
Curtiss P-40 Warhawk NACA 2215 NACA 2209
Messerschmitt Bf 109E NACA 2314.8 NACA 2310.5

15% thickness compared to 14.8% thickness is no big difference imo.
What always makes me wonder is the low stallspeed of the P40 in WB. I just checked it with 100%, the P40 stalls at 80-85mph, the 109E at 140-145km/h , 85-88mph.
Though Red Ants table show clearly that the Emil had the lower wingloading, though the Emil could definitly reach higher lift coefficients, the Emils stalls at higher speeds??? Obviously IEN couldn´t resist to give the P40 a little present.
But ok, without a slight advantage in turning the P40 the early war would be quite uninteresting

AR is aspect ratio.

The P40 was considered to be very manoeverable. This is only partly true. At the outbreak of the war it had a good rollrate compared to other designs. But it wasn´t great by late-war standards, mediocre at best. The 190 rolled twice at fast. Compared to other american designs it was of course manoeverable, those large P47, F6F, P38 fighter naturally can´t be the most manoeverable designs. P51 was designed for high speed and had limited aileron travel way afaik, only 10° up and down. This means though a quite compact design it didn´t roll fast at slow or medium speeds, but stickforces were low at high speeds, where the P51 rolled quite quickly compared to other designs.

Many think the P40 was tough - i don´t think so. Maybe it could withstand MG fire, but over Africa it was shot out of the sky quite easily by german cannons.
The highest success of the P40 was afaik fighting in China against enemy biplanes... (Tiger squad?)

niklas

 

Maybe we should distinguish between the various kinds of turn performance. I mean things like

A) Sustained low G turns at high speeds. The kind that you fly not to really outturn the other guy but to lure him into pulling a few G's too many and bleeding his E away before you go into a real tight turn to get on his six, or just to see whether he's willing to enter a knife fight with you.

B) The really tight kind of turns at low speeds with both opponents pulling as many G's as possible without entering a stall.


Which one do you think the P-40 in the game is too good at?

 

both, form the little i understood

A, 109e has greater thrust/weight
B, p40b has too low stall speed

wild guess.

anyway - what were your sources, boys? you guys came up with decimal numbers