P-39 Expert
Non-Expert
Just the same old official charts. With the same old P-39 numbers penciled in. Do you have a better method to compare planes?
SHOULD the P39 have been able to handle the Zero? Was it training or performance? (3 Viewers)
- Thread starter pinsog
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P-39 Expert
Non-Expert
So these are the famous non-existant 110 gallon tanks?Uh, 90 gal tank for a Spitfire.
View attachment 488043
models
View attachment 488044
US 110 gal paper tank
View attachment 488045
US 110 gal metal tank
View attachment 488046
I see I was beaten to it.
*SkyChimp*
Airman
- 36
- Jan 7, 2018
Real world comparison: A6M2 with a 5'3" 120lb pilot who has eaten nothing but rice and a little fish for weeks on end, who is slightly feverish and a bit queasy and may have malaria, versus a P-39 with a 5'10" pilot, 155lb who has diarrhea, lost a card game last night and most of his script, and who can't get a letter to his pregnant wife back home. Oh, and who had 62 cents in nickels, dimes and pennies that fell out of his pocket and is now rattling around in the cockpit. Who wins?
Ben Rich, in his fundamental "Skunk Works" reminds that Kelly Johnson promised a prize for an idea that that would save a few pounds of weight of an A-12.
Ben Rich proposed to inflate the tyres with helium (that was experimented, but helium very quickly escaped from tyres) and, before each flight, to submit the Pilot to an enema. Kelly replied to Rich to discuss this matter directly with the Pilots.
Shortround6
Lieutenant General
Those are the non-existent in early 1943 tanks (Before August/Sept) or the non-existent for most of 1943 in the Pacific tanks.
Good luck fitting a Spitfire tank on a P-39.
P-39 Expert
Non-Expert
Regarding first paragraph, could you distribute this so everyone will know how to plan an escort mission? If you stay with the bombers then your forward progress is at bomber speed. Thank you. If you stay with the bombers, your forward progress is at bomber speed while your TAS is higher. Weaving is accounted for.
My sources are the official tests and the pilot's manuals. I'll stick with those.
Regarding fuel burn at various altitudes, you can also go up a little higher in your P-39N and burn less fuel too.
Let's do the same exercise for the Thunderbolt. Straight from the pilot's manual. Clean with 305gal internal(no drop tanks, since none were available until August '43). Let's do it your way. Climb to 25000' took 91gal. Cruise at max continuous at 190gph (that big R-2800 used some gas). 305-91gal=214gal divided by 190gph=1.1hr. Take away the 15 min for combat and the 20min landing reserve and you are left with .5hr. That's half an hour, the bombers are going 230mphTAS so you have an escort range of 115mi, divide that by 2 and your escort radius is almost 58mi. That may not even get you TO the English channel from your base.
Lets do this the way the manual says. 305gal less reserve for takeoff and climb to 5000' of 45gal=260gal divided by that 190gph (max continuous)=1.4hr less reserve for combat 15min and landing reserve 20min = .8hr x 230mph (bomber speed) = 184mi divided by 2 = 92mi radius. You may actually see Belgium from there. Remember this includes reserves for combat and finding your airfield to land.
Now let's add the 110gal drop tank. 305+110=415gal less reserve (for T/O&Climb to 5000') 45gal=370gal divided by 190gph = 1.9hr less 15min reserve for combat and 20 minute landing reserve and you are left with 1.4hr at bomber speed 230mph = 322mi divided by 2 = 161mi radius for escort. It's even worse with your method. And you haven't seen Germany before you need to head home.
The whole reason for the 45gal reserve for T/O and climb to 5000' was so the pilot didn't need to use all your calculations. Much easier and very accurate for the pilot. And, if you use 230mph bomber speed (after all, that is your forward progress while weaving) then weaving is accounted for. No combat climb on the initial climb out, just normal climb at 2600rpm max continuous. And sure, if your mission is interrupted by combat you drop your tanks and fight. Then you need to start your journey home then, just like a Thunderbolt.
The ability of the P-39N to fight at 25000' is suspect? What was the P-39s most likely opponent for European bomber escort? The FW190A. At 25000' the combat speed was about the same and the P-39N outclimbed the FW190A by 700fpm. And outturned it too by the way. I think the P-39N would have been successful against the FW190A.
Can we all just admit that you all had not seen these P-39N numbers before now? New information (since late 2012)? If you did see this information then you didn't analyze it. Kind of explains how the Russians did so well with it.
P-39 Expert
Non-Expert
Britain didn't want the P-39 (P-400) because the reason they ordered them in 1940 was in case of a German invasion of Britain. France folded like a deck chair and the British were able to hold the Luftwaffe to a stalemate (effective victory/no invasion) in the fall of 1940 in the Battle of Britain. Lend lease was enacted in early '41 so now Britain (and Russia) will get all the American planes it needs for free. Now the completed P-400s arrived in mid 1941, there is no longer any threat of invasion by Germany. Britain is now supplying their own fighters (Spit & Typhoon) in sufficient quantity that they don't need the P-400s. But these P-400s were PURCHASED under a hard money contract and Bell expected payment. The British were broke and certainly did not want to pay hard cash for planes they could now get for free.
I'm amused by the British's shock at the P-400 performance. Did they just wake up one morning and realize the P-400 weighed too much? Hardly, they ordered them that way. The purchaser (US Army or British) contractually specified EXACTLY the way the planes were to be equipped down to the last rivet. Bell had no choice but to manufacture the planes as ordered. And I'll wager that there was a British representative (or many) stationed at the Bell plant to make sure their purchase was exactly as ordered. They did the same thing to Lockheed by ordering P-38s without turbochargers and then refused to pay when those planes didn't meet specs. Had Pearl Harbor not happened (US now urgently needed all the planes they could get) then Bell and Lockheed would have sued the pants off the British over those contracts. Plus these were brand new designs and had the normal bugs and glitches any new plane had. This is not what you read in the airplane books, but I have read this exact thing before, I did not make it up. And it makes more sense than the British being surprised by low P-400 and P-38 performance. There was no surprise.
michaelmaltby
Colonel
... but watch the Pathe newsreels showing off the "Caribou" to the world ... it was what it was ... but I agree that PH saved the British from legal epics .
The Eastern Front saved the P-39.
The P-400s that the British contributed to the Soviets were pretty clapped out ... if you believe Soviet sources
But while the British were operating the P-400s I'm sure they 'trained' with them hard.
. The Eastern Front saved the P-39.
The P-400s that the British contributed to the Soviets were pretty clapped out ... if you believe Soviet sources
But while the British were operating the P-400s I'm sure they 'trained' with them hard.
This is complete, utter tosh, you have been told why it is tosh, but continue to post it. You ignore the attack on Pearl Harbour and what it meant. The USA, understandably, took all planes it needed for itself so the British never received the P-39s they ordered, they never received all the Mustang 1s (P-51A) they ordered either. You continually blather about weight, but weight doesn't have a huge effect on top speed or climb, power and drag do. The P51B was approximately 30MPH faster than the Spitfire Mk IX on the same engine, not only at top speed but on almost any cruise setting, and it also weighed about half a ton more. By 1943, a matter of months after your famous test the P-39 was barred by the US from being used as a fighter, it was an advanced trainer, too dangerous to its own side to be used in anger. That is the opinion of the USA military in official tests, nothing to do with anyone else.
Shortround6
Lieutenant General
Oh boy, what a load of male bovine excrement. I hardly know where to start.
Lets try with the P-47 example you gave.
The P-47 doesn't need to cruise at max continuous, so there is mistake #1 No need to "cruise at 360mph when the P-39 only has to cruise at 275mph (with tank), slowing the P-47 down to 225IAS (337mph true) cuts the fuel burn down to 145 gallons an hour. Gee whiz that kicks the range after taking out 15 minutes of combat and 30 min reserve to about 250 miles. EXCEPT 225IAS is still too high. We do have a figure of 200IAS which is 300mph true and a fuel burn of a whopping 95 gallons an hour. That 120 gallons in the P-47 after climb, combat and reserve is now 1.25 hours at 300mph or 375 miles? or escorting the weaving bombers 143 miles, not 58.
Mistake #2 the escorts operated in relays so they did not escort from the shores of Britain to the target or as far as they could go. One group would meet up over the Channel and escort in, another group would meet up part way in after flying in a straight line to the rendezvous point and then start weaving. And so on. ONE Group of fighters did NOT weave both going in and coming out. So radius is actually a bit longer.
I don't have a chart for a P-47 with a single drop tank. But an extra 110 gallons should be good for about 1 extra hour at about 300mph. Except it doesn't work quite that way. Climb from several thousand ft to 25,000ft is done on the tank and the tank is dropped fairly soon in the flight (maybe, depends on supply) leaving the P-47 with nearly full tanks at 25,000ft. and inbound.
And as noted the P-47 DOESN'T NEED to cruise at max continuous in order perform this mission.
As for the Fw 190, you know, I have never read where the Bf 109s sat on the ground and let the FW 190s do all the bomber intercepting, can you point me to a source? In fact I have read where they tried to get the 109s to engage the fighters and have the 190s attack the bombers, this is also 1943 so there were a fair number of 5 gun 109s (a 20mm under each wing) also used for bomber intercept so this idea that the P-39s can pick and choose which German fighter they will interact with is Mistake #3.
Mistake #4 I have been a member of this site since 2009, some of the other members have been here much longer, do you really think we have all been ignorant of WW2 Aircraft Performance all that time? There have been a number posts in this forum notifying members about many of the updates as they happened. You are not a modern day Moses coming down from the mount with grand revelations that we unwashed, unbelievers have been ignorant of.
While the YP-39 and the P-39C were being test-flown, Bell Aircraft began work on an export version of the Airacobra known as the Bell Model 14. It was to be powered by a 1150 hp Allison V-1710-E4 engine which had twelve exhaust stacks on each side rather than the usual six. France was sufficiently interested that they ordered 200 Model 14s on October 8, 1939.
All of the media hype surrounding the spectacular performance of the XP-39 prototype had caught the attention of the British Direct Purchase Commission which had visited the USA in 1940 in search of combat aircraft. Seduced by promises of 400 mph top speed, a tricycle undercarriage, heavy cannon armament, and high climb rates, the British ordered 675 examples of the Airacobra. Unfortunately, Bell's glossy advertising brochures did not distinguish between the performance of a lightly-loaded, unarmed, highly-polished experimental prototype and a production fighter heavily-loaded with military equipment and armament, and the British were to rue the day that they ever looked at an Airacobra.
In 1940, the British were desperate for combat aircraft and were willing to consider just about anything that had wings, irrespective of how poor its performance might be. Consequently, when Bell submitted specifications to the British Direct Purchase Commission for a fighter with a top speed of 400 mph, a ceiling of 36,000 feet, and a range of 1000 miles, the Commission literally salivated on the spot and ordered 675 Bell Model 14s sight unseen on April 13, 1940.
The RAF model was at first named Caribou, but the American name of Airacobra was adopted in July 1941. The British Airacobra was virtually identical to the American P-39D, but the slower-firing 37-mm cannon was replaced with the faster-firing and more reliable Hispano 20-mm cannon with 60 rounds. Two 0.50-inch machine guns were mounted in the fuselage, and four 0.30-inch machine guns were mounted in the wings. The engine of the Model 14 was the 1150 hp Allison V-1710-E4 (-35). The British serials of the Airacobras were AH570/AH739 (170 planes), AP264/AP384 (121 planes), BW100/BW183 (84 planes), and BX135/BX434 (300 planes).
Bell began test flying the first Model 14 Airacobra I in April 1941. It carried the British serial number AH570. Tested on the second British Airacobra (AH571) was a revised rudder of more angular shape and less area. Although the aircraft was delivered to England in this form, this rudder was not adopted as standard. A very small dorsal fin just ahead of the rudder became a standard feature of the RAF Airacobras and was also a distinguishing feature of the American P-39D and subsequent versions.
President Roosevelt signed the Lend-Lease Act on March 11, 1941, permitting large quantities of war supplies to be transferred to the Allies. Among the early requisitions under Lend-Lease were three P-39Cs intended for "war tests" plus a batch of 150 Airacobra IAs--the A suffix being used to distinguish between Lend-Lease and Direct Purchase machines, which were otherwise identical. In the event, only the three P-39Cs were ever delivered as British machines, and were assigned the serials DS173/DS175 (USAAF werials 40-2981, -2983, -2984). The P-39Cs could be distinguished from the British Airacobras by the four machine guns in the nose and the lack of wing guns.
The first of these P-39Cs actually arrived at RAF Colerne on July 3, 1941, followed by the other two the next day. It made its first test flight in England on July 6. However, during trials at Duxford, the performance proved disappointing. Although the test pilots praised the general ease of handling of the aircraft, the maximum speed was a shocking 33 mph lower than that anticipated. The fighter proved to be definitely inferior to the Hurricane and Spitfire in climb rate and ceiling, and the 750-yard takeoff run of the Airacobra excluded its operation from some smaller fighter airfields. There was universal shock and dismay among the RAF personnel. What had gone wrong? Bell Aircraft executives later sheepishly admitted that their performance figures had been based on the unarmed and unequipped XP-39 prototype, which weighed a ton less than the armed and equipped P-39C.
The first British-purchased Airacobras began arriving at Colerne before the end of July, joining the three P-39Cs already there. Deliveries of the Airacobra to Britain had to be made by sea, since the Airacobra lacked the range to make the Atlantic crossing. By the end of September, eleven machines had been received. No. 601 "County of London" Squadron was selected to be the first Fighter Command squadron to equip with the Airacobra.
No. 601 Squadron pilots found numerous flaws and weaknesses during their initial work-up with the the Airacobra. Some of them were a question of improving operational efficiency and pilot comfort, but others were considered essential to make the aircraft operational. Numerous modifications were made in the field in an attempt to make the aircraft suitable for combat. A master valve was introduced to allow oxygen to be turned on from the cockpit. The gunsight was modified to improve forward visibility. Changes to the ammunition tanks for the wing guns were made. Modifications were made to the cockpit harness release in order to simplify the operation. The IFF (Identification, Friend or Foe) set was removed from behind the pilot, where it obstructed aft view. A throttle control quadrant friction damper was introduced.
The Air Fighting Development Unit received a British Airacobra I on July 30. They subjected it to tests and completed their report on September 22. They found the aircraft to be pleasant to fly and easy to takeoff and land. Controls were well balanced and although heavier than those of the Spitfire at normal speeds, did not increase appreciably in weight at high speeds as they did in the Spitfire. It was difficult to hold the aircraft in a dive at high speeds unless the aircraft was trimmed nose-heavy. During a turn, the Airacobra would give ample warning of a high-speed stall by severe vibration of the whole airframe. Handling in formation and formation attacks was good, although deceleration was poor because of the plane's aerodynamic cleanliness. Take-offs and landings in close formation were not considered safe, since there was considerable difficulty in bringing the aircraft back to its original path after a swing.
The Airacobra I was powered by an Allison V-1710-E4 twelve-cylinder V in-line engine rated at 1150 hp for takeoff. Weights were 5462 pounds empty and 7845 pounds normal gross. Maximum speeds were 326 mph at 6000 feet, 343 mph at 10,000 feet, 355 mph at 13, 000 feet, 341 mph at 20,000 feet. Initial climb rate was 2040 feet per minute. With an internal fuel capacity of 100 Imp gal the Airacobra had an endurance of 1 hour 20 minutes at maximum continuous cruising speed at 6000 feet, 1 hour 5 minutes at 12,000 feet, and 1 hour 35 minutes at 20,000 feet. The true airspeeds at these altitudes were 287 mph, 327 mph, and 308 mph, respectively. Under most economical cruise conditions, the endurance increased to 3 hours 20 minutes, the relevant speeds being 183 mph at 6000 feet, 217 mph at 12,000 feet, and 215 mph at 20,000 feet. Under maximum continuous climb conditions, it took 15 minutes to reach 20,000 feet. The operational ceiling was considered to be about 24,000 feet, although there was a marked decrease in performance above 20,000 feet. At the Airacobra's rated altitude of 13,000 feet, it was 18 mph faster than the Spitfire VB. However, the speed fell off rapidly above that height, and the two planes were almost exactly matched at 15,000 feet. At 20,000 feet, the Spitfire VB was 35 mph faster and at 24,000 feet it was 55 mph faster. The ground run of the Airacobra during takeoff was 2250 feet, as compared with 1470 feet for the Hurricane II and 1590 feet for the Spitfire V.
The AFDU also did some comparative dog-fighting tests with the Airacobra against a Spitfire VB and a captured Messerschmitt BF 109E. The Airacobra and the Bf 109E carried out mock dog-fighting at 6000 feet and 15,000 feet. The Bf 109E had a height advantage of 1000 feet in each case. The Bf 109, using the normal German fighter tactics of diving and zooming, could usually only get in a fleeting shot. The Bf 109 could not compete with the Airacobra in a turn, and if the Bf 109 were behind the Airacobra at the start, the latter could usually shake him off and get in a burst before two complete turns were completed. If the Bf 109 were to dive on the Airacobra from above and continue the dive down to ground level after a short burst of fire, it was found that the Airacobra could follow and catch up to the Bf 109 after a dive of over 4000 feet. When fighting the Bf 109E below 20,000 feet, the Airacobra was superior on the same level and in a dive.
A similar trial was carried out against a Spitfire V. Although the Airacobra was faster than the Spitfire up to 15,000 feet, it was outclimbed and out-turned by the Spitfire. Unless it had a height advantage, the Airacobra could not compete with the Spitfire. If on the same level or below, at heights up to about 15,000 feet, the Airacobra would have to rely on its superior level and diving speeds and its ability to take negative "G" without the engine cutting out. Above 15,000 feet, the Airacobra lost its advantage in level speed.
The Airacobra was considered to be very suitable for low altitude operations because of the excellent view and controllability, and it was fully maneuverable at speeds above 160 mph. It was not difficult to fly at night, but the exhaust flames could be seen by another aircraft flying three miles to the rear. The flash from the nose guns was blinding, and could cause the pilot to lose not only his target but also his night vision. Firing of the nose guns caused the buildup of carbon monoxide contamination in the cockpit, and this could reach a lethal level very quickly. The guns were fairly inaccessible, and maintenance was troublesome.
By the end of September, No. 601 Squadron had received permission to take its Airacobras into action. On October 9, two Airacobras took off from RAF Manston and flew across the Channel on a "rhubarb"--a code name for a small-scale raid by fighters against targets of opportunity. On this raid, they shot up an enemy trawler near Gravelines. The next day two Airacobras visited the same area, but found no targets. On October 11, two aircraft flew to Gravelines and Calais and hit some enemy barges and then three Airacobras flew to Ostend, but no targets were found.
After these four missions, the RAF Airacobras were taken off operations because of difficulties encountered with the compass. The compass was too close to the guns in the nose, and when the guns were fired, the compass got thrown out of alignment. Deviations of anything from 7 degrees to 165 degrees were recorded. Without a reliable compass, pilots tend to get themselves lost. In December of 1941, the Airacobra was officially withdrawn from operational service with the RAF.
In spite of the problems with the compass and the need for flame dampers for the exhaust and flash suppressors for the nose guns, the RAF concluded that the Airacobra would make an excellent day fighter at altitudes below 20,000 feet and was well suited for the ground-attack role. However, before these plans could be implemented, a decision was made to divert the bulk of the British Airacobra contract to Russia.
By the time this decision was made, production of British-contract Airacobras had reached four a day at Bell's Buffalo plant. The initial contract for 170 planes (RAF serials AH570 thru AH739) had been completed before the end of September, and all but six of these planes had actually been shipped to Britain. However, many of them remained in their crates and were shipped directly to the Soviet Union without being opened. Somewhere between 80 and 100 Airacobras were assembled and flown in Britain by the end of 1941. They were gathered at maintenance units for final modification before being re-crated and shipped to the Soviet Union during 1942. In all, the Soviet Union received 212 of the British Airacobras (some of them shipped direct from the USA), but 49 more were lost at sea en route.
No 601 Squadron relinquished its 13 Airacobras in March of 1942 in favor of Spitfires. One Airacobra was fitted with an arrester hook and was used for deck landing trials at the RAE at Farnborough.
After Pearl Harbor, the USA found itself in desperate need of aircraft to stem the Japanese onslaught in the Pacific. Consequently, nearly 200 of the British direct-purchase Airacobras still in the USA were promptly requisitioned by the USAAC. Although they were similar to the USAAC's P-39Ds, they were not identical and were known by the USAAC under the non-standard designation of P-400. The P-400 designation had, in fact, been associated with the British Airacobras for contractual purposes as early as August 1941. The USAAC P-400s retained their original British serial numbers and their three-color camouflage paint. Most of these planes were used for training stateside, but some of them were rushed to the Southwest Pacific in an attempt to stem the onrushing Japanese advance.
All of the media hype surrounding the spectacular performance of the XP-39 prototype had caught the attention of the British Direct Purchase Commission which had visited the USA in 1940 in search of combat aircraft. Seduced by promises of 400 mph top speed, a tricycle undercarriage, heavy cannon armament, and high climb rates, the British ordered 675 examples of the Airacobra. Unfortunately, Bell's glossy advertising brochures did not distinguish between the performance of a lightly-loaded, unarmed, highly-polished experimental prototype and a production fighter heavily-loaded with military equipment and armament, and the British were to rue the day that they ever looked at an Airacobra.
In 1940, the British were desperate for combat aircraft and were willing to consider just about anything that had wings, irrespective of how poor its performance might be. Consequently, when Bell submitted specifications to the British Direct Purchase Commission for a fighter with a top speed of 400 mph, a ceiling of 36,000 feet, and a range of 1000 miles, the Commission literally salivated on the spot and ordered 675 Bell Model 14s sight unseen on April 13, 1940.
The RAF model was at first named Caribou, but the American name of Airacobra was adopted in July 1941. The British Airacobra was virtually identical to the American P-39D, but the slower-firing 37-mm cannon was replaced with the faster-firing and more reliable Hispano 20-mm cannon with 60 rounds. Two 0.50-inch machine guns were mounted in the fuselage, and four 0.30-inch machine guns were mounted in the wings. The engine of the Model 14 was the 1150 hp Allison V-1710-E4 (-35). The British serials of the Airacobras were AH570/AH739 (170 planes), AP264/AP384 (121 planes), BW100/BW183 (84 planes), and BX135/BX434 (300 planes).
Bell began test flying the first Model 14 Airacobra I in April 1941. It carried the British serial number AH570. Tested on the second British Airacobra (AH571) was a revised rudder of more angular shape and less area. Although the aircraft was delivered to England in this form, this rudder was not adopted as standard. A very small dorsal fin just ahead of the rudder became a standard feature of the RAF Airacobras and was also a distinguishing feature of the American P-39D and subsequent versions.
President Roosevelt signed the Lend-Lease Act on March 11, 1941, permitting large quantities of war supplies to be transferred to the Allies. Among the early requisitions under Lend-Lease were three P-39Cs intended for "war tests" plus a batch of 150 Airacobra IAs--the A suffix being used to distinguish between Lend-Lease and Direct Purchase machines, which were otherwise identical. In the event, only the three P-39Cs were ever delivered as British machines, and were assigned the serials DS173/DS175 (USAAF werials 40-2981, -2983, -2984). The P-39Cs could be distinguished from the British Airacobras by the four machine guns in the nose and the lack of wing guns.
The first of these P-39Cs actually arrived at RAF Colerne on July 3, 1941, followed by the other two the next day. It made its first test flight in England on July 6. However, during trials at Duxford, the performance proved disappointing. Although the test pilots praised the general ease of handling of the aircraft, the maximum speed was a shocking 33 mph lower than that anticipated. The fighter proved to be definitely inferior to the Hurricane and Spitfire in climb rate and ceiling, and the 750-yard takeoff run of the Airacobra excluded its operation from some smaller fighter airfields. There was universal shock and dismay among the RAF personnel. What had gone wrong? Bell Aircraft executives later sheepishly admitted that their performance figures had been based on the unarmed and unequipped XP-39 prototype, which weighed a ton less than the armed and equipped P-39C.
The first British-purchased Airacobras began arriving at Colerne before the end of July, joining the three P-39Cs already there. Deliveries of the Airacobra to Britain had to be made by sea, since the Airacobra lacked the range to make the Atlantic crossing. By the end of September, eleven machines had been received. No. 601 "County of London" Squadron was selected to be the first Fighter Command squadron to equip with the Airacobra.
No. 601 Squadron pilots found numerous flaws and weaknesses during their initial work-up with the the Airacobra. Some of them were a question of improving operational efficiency and pilot comfort, but others were considered essential to make the aircraft operational. Numerous modifications were made in the field in an attempt to make the aircraft suitable for combat. A master valve was introduced to allow oxygen to be turned on from the cockpit. The gunsight was modified to improve forward visibility. Changes to the ammunition tanks for the wing guns were made. Modifications were made to the cockpit harness release in order to simplify the operation. The IFF (Identification, Friend or Foe) set was removed from behind the pilot, where it obstructed aft view. A throttle control quadrant friction damper was introduced.
The Air Fighting Development Unit received a British Airacobra I on July 30. They subjected it to tests and completed their report on September 22. They found the aircraft to be pleasant to fly and easy to takeoff and land. Controls were well balanced and although heavier than those of the Spitfire at normal speeds, did not increase appreciably in weight at high speeds as they did in the Spitfire. It was difficult to hold the aircraft in a dive at high speeds unless the aircraft was trimmed nose-heavy. During a turn, the Airacobra would give ample warning of a high-speed stall by severe vibration of the whole airframe. Handling in formation and formation attacks was good, although deceleration was poor because of the plane's aerodynamic cleanliness. Take-offs and landings in close formation were not considered safe, since there was considerable difficulty in bringing the aircraft back to its original path after a swing.
The Airacobra I was powered by an Allison V-1710-E4 twelve-cylinder V in-line engine rated at 1150 hp for takeoff. Weights were 5462 pounds empty and 7845 pounds normal gross. Maximum speeds were 326 mph at 6000 feet, 343 mph at 10,000 feet, 355 mph at 13, 000 feet, 341 mph at 20,000 feet. Initial climb rate was 2040 feet per minute. With an internal fuel capacity of 100 Imp gal the Airacobra had an endurance of 1 hour 20 minutes at maximum continuous cruising speed at 6000 feet, 1 hour 5 minutes at 12,000 feet, and 1 hour 35 minutes at 20,000 feet. The true airspeeds at these altitudes were 287 mph, 327 mph, and 308 mph, respectively. Under most economical cruise conditions, the endurance increased to 3 hours 20 minutes, the relevant speeds being 183 mph at 6000 feet, 217 mph at 12,000 feet, and 215 mph at 20,000 feet. Under maximum continuous climb conditions, it took 15 minutes to reach 20,000 feet. The operational ceiling was considered to be about 24,000 feet, although there was a marked decrease in performance above 20,000 feet. At the Airacobra's rated altitude of 13,000 feet, it was 18 mph faster than the Spitfire VB. However, the speed fell off rapidly above that height, and the two planes were almost exactly matched at 15,000 feet. At 20,000 feet, the Spitfire VB was 35 mph faster and at 24,000 feet it was 55 mph faster. The ground run of the Airacobra during takeoff was 2250 feet, as compared with 1470 feet for the Hurricane II and 1590 feet for the Spitfire V.
The AFDU also did some comparative dog-fighting tests with the Airacobra against a Spitfire VB and a captured Messerschmitt BF 109E. The Airacobra and the Bf 109E carried out mock dog-fighting at 6000 feet and 15,000 feet. The Bf 109E had a height advantage of 1000 feet in each case. The Bf 109, using the normal German fighter tactics of diving and zooming, could usually only get in a fleeting shot. The Bf 109 could not compete with the Airacobra in a turn, and if the Bf 109 were behind the Airacobra at the start, the latter could usually shake him off and get in a burst before two complete turns were completed. If the Bf 109 were to dive on the Airacobra from above and continue the dive down to ground level after a short burst of fire, it was found that the Airacobra could follow and catch up to the Bf 109 after a dive of over 4000 feet. When fighting the Bf 109E below 20,000 feet, the Airacobra was superior on the same level and in a dive.
A similar trial was carried out against a Spitfire V. Although the Airacobra was faster than the Spitfire up to 15,000 feet, it was outclimbed and out-turned by the Spitfire. Unless it had a height advantage, the Airacobra could not compete with the Spitfire. If on the same level or below, at heights up to about 15,000 feet, the Airacobra would have to rely on its superior level and diving speeds and its ability to take negative "G" without the engine cutting out. Above 15,000 feet, the Airacobra lost its advantage in level speed.
The Airacobra was considered to be very suitable for low altitude operations because of the excellent view and controllability, and it was fully maneuverable at speeds above 160 mph. It was not difficult to fly at night, but the exhaust flames could be seen by another aircraft flying three miles to the rear. The flash from the nose guns was blinding, and could cause the pilot to lose not only his target but also his night vision. Firing of the nose guns caused the buildup of carbon monoxide contamination in the cockpit, and this could reach a lethal level very quickly. The guns were fairly inaccessible, and maintenance was troublesome.
By the end of September, No. 601 Squadron had received permission to take its Airacobras into action. On October 9, two Airacobras took off from RAF Manston and flew across the Channel on a "rhubarb"--a code name for a small-scale raid by fighters against targets of opportunity. On this raid, they shot up an enemy trawler near Gravelines. The next day two Airacobras visited the same area, but found no targets. On October 11, two aircraft flew to Gravelines and Calais and hit some enemy barges and then three Airacobras flew to Ostend, but no targets were found.
After these four missions, the RAF Airacobras were taken off operations because of difficulties encountered with the compass. The compass was too close to the guns in the nose, and when the guns were fired, the compass got thrown out of alignment. Deviations of anything from 7 degrees to 165 degrees were recorded. Without a reliable compass, pilots tend to get themselves lost. In December of 1941, the Airacobra was officially withdrawn from operational service with the RAF.
In spite of the problems with the compass and the need for flame dampers for the exhaust and flash suppressors for the nose guns, the RAF concluded that the Airacobra would make an excellent day fighter at altitudes below 20,000 feet and was well suited for the ground-attack role. However, before these plans could be implemented, a decision was made to divert the bulk of the British Airacobra contract to Russia.
By the time this decision was made, production of British-contract Airacobras had reached four a day at Bell's Buffalo plant. The initial contract for 170 planes (RAF serials AH570 thru AH739) had been completed before the end of September, and all but six of these planes had actually been shipped to Britain. However, many of them remained in their crates and were shipped directly to the Soviet Union without being opened. Somewhere between 80 and 100 Airacobras were assembled and flown in Britain by the end of 1941. They were gathered at maintenance units for final modification before being re-crated and shipped to the Soviet Union during 1942. In all, the Soviet Union received 212 of the British Airacobras (some of them shipped direct from the USA), but 49 more were lost at sea en route.
No 601 Squadron relinquished its 13 Airacobras in March of 1942 in favor of Spitfires. One Airacobra was fitted with an arrester hook and was used for deck landing trials at the RAE at Farnborough.
After Pearl Harbor, the USA found itself in desperate need of aircraft to stem the Japanese onslaught in the Pacific. Consequently, nearly 200 of the British direct-purchase Airacobras still in the USA were promptly requisitioned by the USAAC. Although they were similar to the USAAC's P-39Ds, they were not identical and were known by the USAAC under the non-standard designation of P-400. The P-400 designation had, in fact, been associated with the British Airacobras for contractual purposes as early as August 1941. The USAAC P-400s retained their original British serial numbers and their three-color camouflage paint. Most of these planes were used for training stateside, but some of them were rushed to the Southwest Pacific in an attempt to stem the onrushing Japanese advance.
179 of the Airacobras sent to Britain were re-acquired by the USAAF and were sent to North Africa to join the Twelfth Air Force.
Disposition of RAF Airacobras
AH573 crashed Feb 11, 1942 from Boscombe Down. Engine failure just after takeoff. Pilot killed.
AH576 in belly landing Aug 29, 1941
AH581 crashed after engine failure Nov 21, 1941.
AH582 crashed during aerobatics Oct 19, 1941. Pilot killed.
AH596 in forced landing at Colchester Sep 29, 1941.
AH602 crashed during aerobatics Jan 12, 1942.
AH603 crashed on takeoff Dec 12, 1941
AH733 delivered to RAF, but transferred to USSR
Disposition of RAF Airacobras
AH573 crashed Feb 11, 1942 from Boscombe Down. Engine failure just after takeoff. Pilot killed.
AH576 in belly landing Aug 29, 1941
AH581 crashed after engine failure Nov 21, 1941.
AH582 crashed during aerobatics Oct 19, 1941. Pilot killed.
AH596 in forced landing at Colchester Sep 29, 1941.
AH602 crashed during aerobatics Jan 12, 1942.
AH603 crashed on takeoff Dec 12, 1941
AH733 delivered to RAF, but transferred to USSR
P-39 Expert
Non-Expert
Russians had a joke "Pilots over 40 not permitted to fly Aircobra (sic). Balls get caught in propshaft!
In practice the driveshaft arrangement worked extremely well without vibration even during a wheels up (crash) landing.
P-39 Expert
Non-Expert
I have heard all the hearsay about the British and the P-400. I did not ignore Pearl Harbor, mentioned it was the reason there were no lawsuits. Weight has more to do with climb rate than any other factor if HP is the same. P51 in all its forms was much more aerodynamic that any mark of the Spitfire. And finally the P-39 was no more dangerous to operate than any other American WWII fighter. Chuck Yeager's favorite plane (prior to Merlin P-51), and he also flatly stated that he did not know any pilots who did not like the P-39. This at a training base where almost all fighter pilots trained on a P-39. And I can tell you either did not know this information existed or did not review it in any detail. Sorry to try and introduce you to anything new since you already know it all. Just keep denying every single fact that I give you.
You have posted yourself that P-400s had British oxygen systems, that wasn't because the British rejected them it was because the USA took them for their own use, it was now at war. Similarly, as previously posted 179 P-39s were re acquired in UK and sent to Africa. At the same time US pilots in UK were flying Spitfire mkVs on reverse lend lease.
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fubar57
General
This book has many pilots who did not like the P-39
Propaganda by the British secret service, F.Dorr was the nom de plume of J. Bond.
P-39 Expert
Non-Expert
Okay, mistake #1. P-47 didn't need to cruise at max continuous power. Okay, then the P-39N didn't need to cruise at max continuous power either. And yes the did need to cruise at max continuous over Europe because the Luftwaffe was the toughest enemy we faced and they controlled the air over Europe. So you went as fast as you could, period. Just to give you an idea of how tough it was, the 8th Air Force had more casualties in WWII than the MARINE CORPS. So yes, you cruised over Europe at max continuous power, if you wanted to come home.
Mistake #2, yes escorts were in relays mainly because there were different types of planes (P-38, P-47 and P-51) that all had different ranges. P-39 would have been extremely useful in the early or intermediate ranges, like the P-47 or earlier P-38.
Mistake #3, the FW 190 was the predominate fighter in the west supplemented by Me109s. Me109s were the predominate fighter in the east supplemented by the FW190. The P-39N performance compared favorably with the Messer also, would you like a graph comparing the two?
Mistake #4, you obviously have not seen this information before or you would not be vehemently denying absolutely every fact that I give you. Straight from the official tests or the pilots manual. You keep coming back with "no altitude performance, no range, tumbled, bad stall, British hated it (that one's true but not for the reasons you claim) and on and on. I'm certainly not Moses but you obviously didn't know this newer information. Try and put all that old P-39 hearsay out of your mind and objectively look at some new information.
I'm enjoying our conversations, maybe someday you will too.
buffnut453
Captain
Ignoring for a moment the fact that Yeager has a less-than-stellar reputation in many parts, this is just one data point...the opinion of a single pilot. Per Fubar57's Post #957, there were plenty of pilots whose opinions differed vastly from Mr Yeager's. One data point does not disprove hundreds of other contrary data points!
It's not that we didn't know. I'm afraid some of us just don't care because the vast majority of evidence (ie facts) point in a different direction from the selective measures you are providing.
Yes, there are small individual use cases where a P-39 might be comparable or even better than carefully selected contemporary machines. However, taken as a whole, the P-39 just didn't have the performance when it was needed...ergo it was essentially discarded.
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