Flying Tigers (AVG) and no P-40

[Shortround6]

I have voiced this theory before and have nothing to back it up but here it is again.

In 1939 and part of 1940 the American .50 cal cycled at 600rpm and that is on test stands. In actual aircraft the cycle rate some times fell to 500rpm and that is for UN-synchronized guns. At some point in 1940 the guns were up-graded to the 800-850rpm rate of fire standard.
It might depend on WHEN the British made their request for the 6 guns. Six X 10rps= 60 rps. four X 14rps= 56rps. Given the number of months it took to get a modification for drawing board to service squadron some overlap of when the guns were upgraded might be an explanation.

 

[Lighthunmust]

I am late to this thread, and only skimmed through some of the postings. Many great postings regarding the AVG. If someone already answered with the information below, I apologize for the redundancy.

I pulled out "Flying Tigers" by Daniel Ford and "The Great Book of Fighters" by William Green and Gordon Swanborough. If the P-40 never existed: they would probably use Curtis Hawk 75s with a fixed gear. The Chinese had already assembled a version of this called the 75-M. Chennault had been flying one for a while before the creation of the AVG.

Chennault did not like inline engines, but the speed advantage of the P-40 and availability convinced him to request them. The P-43s arrived in China during April 1942. Chennault thought they were death traps due to lack of pilot armor and self-sealing tanks so the AVG did not use them and they went to the CAF. The AVG disbanded three months latter.

TGBofF has a photo of a fixed gear H-75.

 

[Lighthunmust]

I have voiced this theory before and have nothing to back it up but here it is again.

In 1939 and part of 1940 the American .50 cal cycled at 600rpm and that is on test stands. In actual aircraft the cycle rate some times fell to 500rpm and that is for UN-synchronized guns. At some point in 1940 the guns were up-graded to the 800-850rpm rate of fire standard.
It might depend on WHEN the British made their request for the 6 guns. Six X 10rps= 60 rps. four X 14rps= 56rps. Given the number of months it took to get a modification for drawing board to service squadron some overlap of when the guns were upgraded might be an explanation.

From my posting in the Alternately Armed P-38 thread is another possibility I would like confirmed or dismissed:

"I have found a secondary sources without specific documentation of this information, just a list of sources. I checked Tillman's "Wildcat" and all I found was that at one time there were two separate production lines at Grumman for F4Fs and Martlets. According to Dean in AHT page 494 Gun Platform and Weapon Performance there were many complaints from USN aviators such as "The reduction of rounds per gun cut the firing time by at least five seconds. That doesn't seem like much, but can be a lifetime in combat". Dean writes "The FM-1 and the FM-2 versions by Eastern went back to four guns with more ammunition per gun. THE BRITISH, WHO INSTIGATED THE SIX GUN ARRANGEMENT THE -4 VERSION USED FOR COMMONALITY OF MANUFACTURE, STAYED WITH THIS CONFIGURATION." (capitalization added for emphasis) Dean is a respected source. I think Grumman, who would soon stop making Wildcats to concentrate on Hellcats, decided to make a production decision to reduce the costs of running two production lines and the USN Brass did not care."

 

[renrich]

RCAFson, with all due respect but I don't know where you took physics and math but the difference is not "less than 200 pounds" but rather almost 276 pounds. I had to take physics to get a degree in Geology but I certainly never liked it and only did enough to get by However there is more than simple physics and weight to explain the climb rate of aircraft. For instance, the P39Q-1 at 7570 pounds took 1650 feet of runway to get off the ground. The F6F3 at 7543 pounds only took 690 feet so obviously the two aircraft with similar weight and similar power climb differently.

Having said all that, I agree that weight plays an important role in climb rate and a 276 pound difference is not a major factor although it does have some impact. You say that Eric Brown may be biased for the Wildcat(Martlet) since he shot down two FW200s with it but in his book, he makes no bones about the Wildcat being a more lethal fighter than the Sea Hurricane. The way I read it however is that he is being objective, not biased.

As for the "myth" about F4F performance and your exercise in physics, I say "garbage in, garbage out" because there are huge variations in the weight of various F4Fs, (just like I stated in an earlier post.) Take a look at these figures:
From the Williams site- F4F3 # 1845 weighed 6260 pounds during the performance tests and got 331 mph (this could be where the good numbers, climb and Vmax for the F4F3 came from)
Dean states that the F4F4 picked up about 350 pounds empty weight over the F4F3. That is a significant weight gain and could have a fairly big impact on performance.
The F4F3 fighter gross weight was 7150.7, the F4F4 overload fighter weight was 7972.5 with the six guns. Big difference of more than 800 pounds. I believe that all the F4F4s at Midway carried the six guns.
The F4F4 fighter weight was 7426 pounds but that was only with four guns.
One can readily see that when quoting performance of the F4Fs it is vital to match performance to the weight of the aircraft tested.

There is no doubt that the F4F4 with six guns( because the Brits insisted on the six) was a mistake and it was rectified later when the Wildcat went back to four guns with more ammo per gun.

As to the idea that carrier based planes have a built in advantage over land based explaining why the Wildcat seemed to have been more effective than the P40 or Hurricane against the A6M, consider this. I know of few if any instances where land based fighters had to deal with more adverse circumstance than the F4F4s did at Henderson field in 1942 and early 1943. The pilots and ground crewman were sleeping often in slit trenches in the mud. They were being sniped at by Japanese riflemen. They were under long ranged artillery fire from the island. They were shot at from the ground on takeoffs and landings.They often endured bombardments at night from BBs and CAs. They were being bombed from the air. They suffered from malnutrition and all sorts of tropical diseases and the horrible tropical climate and sometimes they were given an 03 and told to go to the front lines and help out. The airplanes were suffering from all of the above too. Yet, the Wildcats and the pilots did an incredible job. Maybe it was a case of exceptional pilots or an exceptional airplane or a mixture of both but the record is there to be examined.

 

[RCAFson]

Using a bit of hocus pocus and guesstimations, and some hand measuring from internet drawings, I calculated some downward viewing angle of various WWII aircraft. There was some problem establishing the design eye position.

The Hurricane seems to have 7 to 8 degrees of view over the nose, based upon my measurements of drawing and photos.

 

[RCAFson]

The F6F3 at 7543 pounds only took 690 feet so obviously the two aircraft with similar weight and similar power climb differently.


The way I read it however is that he is being objective, not biased.


As for the "myth" about F4F performance


There is no doubt that the F4F4 with six guns( because the Brits insisted on the six) was a mistake and it was rectified later when the Wildcat went back to four

I know of few if any instances where land based fighters had to deal with more adverse circumstance than the F4F4s did at Henderson field in 1942 and early 1943.

The P39 only has 213 sq ft of wing area versus 260 on the F4F while only being slightly lighter.

Brown's views on the Martlet/Sea Hurricane are contradictory. For example on Page 66 of Duels in the Sky he states that the Wildcat was faster and more manoeuvrable than the Sea Hurricane, but then in the mock combat on page 210 he admits that the Sea Hurricane IIC could out-turn, out-roll and out dive the F4F...and while he states that the Wildcat could outclimb it, we know that this simply isn't true, since the Sea Hurricane IIc could climb to 20K ft, using normal power, several minutes faster than any variant of the F4F, using military power, except the FM-2. Flying side by side the Sea Hurricane, the Martlet did not exhibit any sign that it was a more deadly fighter.

The Standard Aircraft Characteristics chart, dated Aug 14 1942 states 7556 lbs for an F4F-3. However, I am heartened to see that you admit that the 3300 fpm climb rate claims have no basis in fact.

Yet, the F4F-4 probably scored the majority of F4F kills. This would imply that tactical advantages of height, surprise and firepower were more important than other factors.

OTOH, the IJN's A6Ms were flying at the extreme end of its range, and according to Lundstrom, many pilots held on to their drop tanks and ditched their radios, while their ability to use their engines at combat power and engage in lengthy pursuits was severely limited and these factors gave the F4F an additional tactical advantage. Flying out of Burma, NEI or Malta was no picnic either.

 

[renrich]

Don't put words in my mouth. I am sorry you won't be heartened because I never said the 3300 fpm climb rate had no basis in fact. I go by what Dean said. I believe his credentials are substantially better than anyone's on this forum. The whole pupose of this thread is to identify an airplane which could have served the AVG if the P40 had not been available. My opinion is that, if it had been available, the Wildcat could have served very well. If you want to really become informed about American fighters in WW2, get a copy of "America's Hundred Thousand" and you will see that your Standard Aircraft Characteristics chart only gives part of the picture.

The point about Brown which you won't admit is that when he had a mock dogfight with one Wildcat the pilot of the Wildcat may have been a rookie with no combat experience. He was comparing the Hurricane IIC with the F4F4 which was the worst performing Wildcat, thanks to the Brits. It is clear that when Brown gives his opinion about the Sea Hurricane I V the FW200 and the Wildcat V FW200, that the Wildcat is the more lethal fighter.

"You can lead a horse to water but you can't make him drink."

 

[RCAFson]

Well, I am disappointed because the evidence is pretty overwhelming that 3300 fpm was out of reach of the F4F-3 even at 6262 lbs, which is far below a typical combat weight.

Brown states (in the quote from p210, that I posted earlier) F4F-4 Wildcat Versus Sea Hurricane lIC: "Verdict: This is a combat I have fought a few times in mock trials." He doesn't state which aircraft he flew in, and it is quite probable that he alternated between the two types. OTOH, the Sea Hurricane IIC was heavier than any other Sea Hurricane variant. I take Brown's comments regarding the FW-200 to indicate a rough parity between the Sea Hurricane and the Wildcat. Certainly the Sea Hurricane I had no problems with the FW-200, being the first to bring one down (or later the Ju-290), other than what would be expected in attacking such heavily armed aircraft.

 

[tomo pauk]

Dean states RC of FM-2 as 3200 ft/min @ SL, yet the F4F-3 has 3300 ft/min. Wonder how is that possible, since the FM-2 have had almost 20% more power available, while being only 20lbs heavier (empty weight 5426 vs 5448lbs for FM-2 (NavAir data))?

 

[Shortround6]

I think part of the problem maybe that not only were some of the early F4F-3 figures estimates or optimistic, but they were based off conditions that were never going to happen in a war zone. The F4F-3 in "fighter" configuration was not carrying a full load of ammunition. It was also not using full internal fuel. This can 'shave' 400lbs from the weight of the F4F-3. And if you are comparing the performance of an "Early" F4F-3 to later F4F's you also have no armor or self-sealing tanks which may save another 300 or more pounds. There is almost a 10% difference in the weight of "clean" F4F-3s right there. Weight charts are listed for the "bomber" mission which require the removal of 2 of the .50 cal guns and their ammo. Now was any combat unit in the SP really going to fly with only a single .50 in each wing to carry a pair of 100lb bombs or were they going to stay on the runway a little longer?

 

[tomo pauk]

In other words, the quoted climb performance of the F4F-3 was achievable only by a plane that could hardly been declared as combat worthy?

 

[Shortround6]

In other words, the quoted climb performance of the F4F-3 was achievable only by a plane that could hardly been declared as combat worthy?

Sort of!!!
Timing is everything.
The first 54 F4F-3s for the Navy are ordered Aug 8th 1939. Nobody's planes had armor or self sealing tanks.
French place an order for 100 aircraft in Oct 1939, these will become British Martlets.
July of 1940 sees the 2nd production F4F delivered and mad scrambles in Europe to fit protected tanks and armor not only to new planes but planes already in service. It takes a bit longer for the US to catch up.

Weights for some of these configurations are on the WW II performance website and in Dean's AHT. The reduced fuel for the F4F-3 may be 110 US gallons, which, while less than a full load is about as much as a Spitfire, Hurricane or 109 carried when full. The reduced ammo load still leaves 280-300rpg, again, while not a full load is more than some army planes (P-40s) carried for their guns a couple of years later.

 

[RCAFson]

Sort of!!!
Timing is everything.
The first 54 F4F-3s for the Navy are ordered Aug 8th 1939. Nobody's planes had armor or self sealing tanks.

Even at 6262lbs, which is far below the combat weight of an F4F-3 without armour or SS tanks, the plane cannot achieve 3300 fpm:

http://www.wwiiaircraftperformance.org/f4f/f4f-3-1845-performance.jpg

and you can see where the military power climb rate has been faintly pencilled in. This aircraft had no armour, SS tanks and was equipped with 2 x .3" and 2 x .5" MGs: http://www.wwiiaircraftperformance.org/f4f/f4f-3-1845.pdf and no USN F4F-3 ever went into combat in this configuration. 3300 fpm for the F4F-3 is a myth that seems to have arisen from the fact that it was in the original F4F-3 specs but was never achieved in an actual F4F-3.

 

[davparlr]

Sorry to return to a previous diversion.

Some comments on deflection shooting.

First, it seems as inconceivable to me that deflection shooting would not be taught to fighter pilots as not teaching a quarterback to lead the receiver in football. Of course it is inconceivable that the Navy and AF would not teach dissimilar combat to its fighter pilots prior to the Vietnam War.

Second, it does seem someone in the army is concerned about over the nose deflection shooting. In a military review of the P-51A in Dec, 1942, these comments, in Spitfireperformance, were recorded.

f. The view downward over the nose is not sufficient to allow full deflection shooting in a turn.

(3) Every effort must be made to increase the angle of view over the nose. At present the view over the nose is restricted to 3° 4' below the sight line.

Third, I am not sure how much advantage view over the nose is for a successful fighter. The highly successful Bf-109 had almost zero over the nose vision. A two degrees difference, slightly less than the difference between the P-51B and the F4F, and at a thousand feet, the linear distance viewed is 37 ft., or about one aircraft length, at five hundred feet., half an aircraft length. That doesn't seem to me to be significant, helpful, yes. Some performance is typically lost, neither the F4F nor the F6F were considered greyhounds, but I don't think the over the nose viewing was completely to fault. Both the F4U and P-51 increased downward viewing by increasing pilot position, apparently without significant impact to airspeed.

Forth, Lundstrom, in an otherwise well referenced and written book, was strangely delinquent in references to non-Naval deflection shooting. My gut reaction was that he used only Naval sources for references regarding Naval uniqueness in deflection training, otherwise he would have referenced them. Without that, his comments regarding this are weak. It doesn't help that the book was published by the Naval Institute Press. I am not saying he is wrong, or trying to be deceitful, or even trying to slant the information, only that, in order to really be convincing considering all his sources and the publisher, he really needed to reference other sources such as AAF, RAF, etc., training syllabuses. As it is, to me, it is just a statement of a Naval position.

 

[Shortround6]

Well, there is being taught something in class and practicing it once or twice a year (or once or twice before going into combat) and being taught something and practicing it a lot. Give me an hours class room instruction on the golf swing and 15 minutes on a practice and I guarantee you the ONLY safe place on the course will be the green

Thach had been a Naval aviator since 1929 and for a number of years was an instructor and known gunnery expert. How much flying and gunner practice did some of these pre-war Navy pilots get?
Pre-war for US is pre-Pearl Harbor which might have loosened the purse strings for training of existing pilots a bit before the big influx came.

 

[renrich]

Dav, your post is well considered, IMO and perhaps right on the mark. I do think there needs to be the distinction made that there is a difference between deflection shooting and FULL deflection shooting. (my caps) The USN, according to Lundstrom put a lot of emphasis on learning full deflection shooting. Those type of gunnery runs( high side, low side and flatside along with the overhead) are mentioned frequently in combat in his books but I don't, in my reading, hear them being mentioned in other books about other airforces. If you look at the post by Leonard of the AAF discussion of air fighting, there is no mention of full deflection shooting. Also there, AFAIK, have been no posts on this forum that demonstrate how other air forces trained their pilots in full deflection gunnery runs. Our friend Bill(Dragondg) (sp?) who probably is the best informed member of this forum on USAAF WW2 has not commented much about AAF gunnery training in deflection shooting.

To me, there is no doubt that trying to execute a full deflection gunnery run was very difficult and the other air forces may have thought it not worth the trouble to teach. On the other hand some deflection shooting theory had to be taught because every attack could not be either directly from the six o clock position or head on with zero deflection but there is a big difference in the lead required for a ten or twenty degree angle off and a ninety degree angle off. It may be that Lundstrom never thought that his assertions about naval aviator gunnery would be subjected to as much scrutiny as they have been here in this forum

My last comment on the F4F3 performance is as follows, although I know that Dean does not have much credibility with some members: Page 597, "America's Hundred Thousand" "The FM2, had both more power and greater weight than earlier machines, but succeeded in getting climb time capability almost back to best F4F3 performance. Climb to 20000 feet in that aircraft took about eight minutes."

One notices that Dean said "best F4F3." All F4F3s were not created equal. One can quibble about whether the best climbing F4F3 was combat ready with the load carried but there is no doubt in my mind that some F4F3s had very good climb characteristics.

 

[tomo pauk]

Excerpt from the pdf posted @ Fulmar vs. Wildcat thread:

 

[Lighthunmust]

The comments about USN training for deflection shooting bring to mind another topic discussed on this forum. What is firepower? Short amounts of devastating power or long amounts of sufficient power? Could it be that this USN deflection training resulted in the need for firing bursts longer than 2-3 seconds to allow for aiming errors to be corrected by length of projectile stream? Same concept as the way shotgun pellets fly through the air not in a wide short fan but in a widening stream for most efficient target destruction. Could the use of this deflection training in combat explain some of the complaints USN Aviators had with the shorter firing times of the F4F-4 in comparison to the F4F-3?

As I posted earlier, Chennault preferred radial engines to inlines. He was very familiar with the fixed gear Hawk 75 from flying one in China. If both the P-36 and the F4F-3 were available, he would have had a hard choice to make. Go with what he knows or go with an unknown that promises better performance. Chennault would be aware of the Zero's debut in China in 1940, but have little definitive knowledge of it capabilities. Considering his lengthy supply chain, poor quality landing fields, and some Chinese mechanics familiar with Curtis products and none with Grumman; I'm guessing he would go with the P-36. Most of his adversaries would be Nates and Oscars, so the P-36 would be competitive. With good tactics and flying skills the P-36 could shoot down Zeros, as it did with USAAF pilots in the first days of December 1941.