"FM-2 vs F4F-4" Topic

My father served in the USN as a carrier pilot in WWII. He flew just about all the different planes – Dauntless, Avenger, Helldiver, Hellcat, and the various marks of Wildcats. He maintains thew General Motors Wildcat, FM-2, was the best and most maneuverable of the Navy's WWII fighters. The F4F-4 added weight in the wings with six vice four .50 calibre machineguns. The FM-2 scaled that back to four, had a more powerful engine, and had an obviously larger vertical stabilizer (I do not know what that did for the plane, though). I have never heard this opinion before or since, but it comes from someone who flew them and had a distinguished career.

So, my father could be:
1. Completely wrong.
2. Right, and the improvements of the F6F over the F4F and re-tooling of Grumman's production line just could not be reversed.
3. Right, in that he found it to be better, in the same way that some people have an affinity for certain cars, tools, game tactics, etc, that no one else can put to the same in the same way.

Does anyone have any insight into the differences between the various Wildcat models?

Thanks!

Gregory

It would appear that he is at least partially correct in his assessment of the FM-2. The FM-2 did have only 4 .50's but it was capable of carrying 2 250lbs of bombs vs. the F4F's ability to carry 2 100lb bombs. The lack of the extra .50's may have been enough to make a difference in the maneuverability. The engine remained the same as in the F4F-3. It was the Pratt & Witney 14-cylinder R-1830-36 Twin Wasp which had 1200hp and gave it a max speed of 318mph at 19,000 feet.

I believe the increased size of the vertical stabilizer made the FM-2 more, well, stable as the name would imply.

The F6F was undoubtedly a superior aircraft in nearly every aspect – given that it was designed from lessons learned about the shortcomings of the F4F. However, that doesn't mean that the FM-2 wasn't more maneuverable. As an example – biplanes are inherently more maneuverable than a monoplane, but they aren't nearly as fast – nor as rugged.

If your father is still around, sit him down NOW with a tape recorder and have him reminisce. Not only will this be important for any decendents but the National Archives is collecting war stories from veterans. If you know a Boy Scout who needs an Eagle project, this qualifies.

Wyatt

The Hellcat was more maneuverable than any make of Wildcat as a matter of fact it was the first naval fighter that could turn inside the zero. Also I don't believe any model Wildcat was armed with more than 4 X .50cal.

jdg

This isn't conclusive, but the on-line flight simulator Aces High models the FM-2 as being more maneuverable than the F4F-4:

link

Jdginaz, I think your info is a bit off.

The F4F-4 Model sported 6 .50 Brownings. The F4F-4 was the largest production run of the Wildcat by Grumman's Iron Works. The Eastern Aircraft Division of General Motors assumed production of the Wildcat line when Grumman switched to production of the F6F Hellcat. The fact that the Wildcat continued in production beyond the introduction of the Hellcat speaks well of the usefulness of the tubby little fighter on Escort carriers.

The F4F-4 Model sported 6 .50 Brownings. The F4F-4 was the largest production run of the Wildcat by Grumman's Iron Works. The Eastern Aircraft Division of General Motors assumed production of the Wildcat line when Grumman switched to production of the F6F Hellcat. The fact that the Wildcat continued in production beyond the introduction of the Hellcat speaks well of the usefulness of the tubby little fighter on Escort carriers.
As to maneuverability? From accounts I've read the Wildcat was a joy to fly and could even fly inverted for sustained periods of time due to it's pressurized oil delivery system. (Don't try that with a Hellcat!) But aerial combat DEMANDS much more from a fighter aircraft. And the Hellcat delivered MUCH more. Power, climb, range, firepower and even more of the legendary Grumman ruggedness.

The F4F-4 Model sported 6 .50 Brownings. The F4F-4 was the largest production run of the Wildcat by Grumman's Iron Works. The Eastern Aircraft Division of General Motors assumed production of the Wildcat line when Grumman switched to full-time production of the F6F Hellcat. The fact that the Wildcat continued in production beyond the introduction of the Hellcat speaks well of the usefulness of the pugnacious little fighter.
As to maneuverability? From accounts I've read the Wildcat was a joy to fly and could even fly inverted for sustained periods of time due to it's pressurized oil delivery system. (Don't try that with a Hellcat!) But aerial combat DEMANDS much more from a fighter aircraft. And the Hellcat delivered MUCH more. Power, climb, range, firepower and even more of the legendary Grumman ruggedness.
I can understand why your father loves the Wildcat. I've read many quotes from pilots who were unhappy to switch mounts (i.e. Spits to Jugs, 109's to 190's, etc.) but I don't recall such comments about a Hellcat upgrade.

P.S. Capt Eric Brown (RN) had very nice comments about BOTH models!

Nobody warned me not to use the tab key! Sorry about the 3 posts instead of one.

The FM-2 was the best production version of the Wildcat. It featured reduced weight with the reduction of armament back to 4 M2 Brownings, but with increased ammo. It's upgraded engine featured more power (thus the need for a bigger stabilizer) and later had a "war emergency" overboost capability. Increased horsepower + reduced weight meant it was more manueverable, and had a better climb rate than previous models. It was more manueverable than a Hellcat, but the Hellcat had so many other advantages that the two are not really comparable.
The Hellcat had twice the power of the FM-2, giving it a max takeoff weight almost double the FM-2. This meant that it could drag a lot more into the sky, be it fuel, bombs or rockets. The Hellcat was over 50MPH faster than the FM-2 and could outclimb it, out run it, and outdive it.
Still the FM-2 filled a niche, providing excellent support for convoys and invasion forces. It's pilots even demonstrated that they could take on the best the Japanese had to offer at Leyte Gulf, when they helped turn back a superior Japanese surface force through their tenacity.

Hi

The term "maneuverability" is a loose term with no real consensus on meaning. I would do a long post on this, but it is beside the point.

I will start with "the hellcat could turn inside the zero".

Actually, NO. "Turn" has two components if you leave out the rate of roll to get into the turn in the first place. First, you have "initial turn" this is the minimum turn radius the aircraft is capable of.

Listen carefully here: no hellcat, no wildcat EVER had a smaller initial turn rate than ANY zero. We are talking about a circa 200m radius with the Zero, 230-40 for various lightweight versions of the wildcat, and 290 or so for ANY version of the Hellcat. However, At high speed, the initial turn radius is regulated not by the plane but by the pilot. Simply at say 300mph, both planes are capable of pulling so tight a turn that the pilot blacks out.

This gets into the concept of "Sustained rate of Turn".

It takes energy to turn. At these higher speeds, the Hellcat has much better "Specific Excess Power" than the Zero, and where both planes are turning in some sort of ideal circle 180 degrees apart, the zero slows faster, and the hellcat walks up and gets the shot.

The wildcat doesn't have this superiority in energy over the Zero.

Thus, its more complex than THAT.

Rocky

Several sources say that at >250 mph, the Zero had heavy ailerons which reduced it's maneuverability. Maybe it's not just pilot factors at high speed turn. The Allies also had suits to reduce G-effects. Aircraft in general with vicious and sudden stall behavior may have better maneuverability "on paper" In the hands of a test pilot where a stall won't make one helpless in the face of the enemy, this might not make a difference. In combat, pilots may be reluctant to push the envelope. Vs AC with theoretically inferior performance but with greater ability to predict stall, the real world turn might actually be better.

Bruce Kohrn

Hi

Heavy Ailerons are correct, as I said in the above post "EXCEPT ROLL". This affects how quickly it rolls into a turn. In fact, the Zeke has about the slowest roll rate of a WW2 single engined fighter in the world. Mostly didn't matter due to the tactics used.

As for stall characteristics, when the german pilot reports outturning the Spit, he is reflecting the different stall characteristics involved. But this doesn't apply in the pacific on the origin of THIS thread as well.

Rocky

Since you mentioned Hellcats, that would seem to open the discussion parameters a bit <g>. I've seen in print "data" showing Bf 109 had a better turn radius than both Hurricane and Spitfire.
BTW, what would a climbing or diving turn due to the competitive turn discussion? And when Zero had its drop tank? How much fuel carried at the time of combat, the relative place on the altitude performance curve and no doubt numerous other variables might "on any given Sunday" be just enough of an edge to effect results.
Double BTW, any data on when / if the counter-G suit used by Navy / Marine / AAF or Commonwealth in the Pacific? Were these exported to the Chinese or Soviets?

Bruce Kohrn

I tend to believe people who were actually there as opposed to wargamers, books, and well read experts. I am also inclined to believe that there were more than a few mods (local or otherwise) that didn't hit the books.

Haveing argued with more than one "wargamer" about a plane near and dear to my heart – the B-52 – a plane I flew – I can appreciate the inaccuracy of some of the opinions – many of which came from some book or the other – that wargamers come up with.

In short, if your Dad actually flew the thing – believe him. He isn't lying and he isn't wrong. Many small things make a plane what it is. The larger stabilizer may have added a bit of snap he liked, maybe the larger ehgine came from a Hellcat. Who knows. What matters is that a guy who actually flew all of those planes, was actually there, maybe got shot at in it, has an opinion vastly better a dusty book written as 50% propoganda and 50% opinions of non flyers.

In short, I believe folks who were actually there 100% of the time over anyone who wasn't.

"Half of writing history is hideing the truth."

Hi

BK… That refrence to the 109 is in the back of a book on the Battle of Britain. And in the old profile series. And is sort of correct.

Remember the earlier post about the Hellcat? Sort of the same thing. There are several considerations. That refrence you saw about the 109 outturning the brits is ONE of them. At high speed, the 109 has two distinct advantages. The lesser one is that it has superior "specific excess power" than the spit, and way more than the hurry most of the time. This means that if both pilots are pulling maximum G, the 109 transits a greater number of degrees of arc. Or in english, the 109 keeps more speed. The second advantage is the high speed stall characteristcs of the three aircraft, which is what the article WAS NOT talking about. The spit has a particularly sudden "high speed stall" that is difficult to feel coming. When this happens, it snaps inverted and spins, needing about 5000 feet for the recovery! Now, if you have a low level dog fight, the spit pilot, aware of his problem might not pull as hard as he might out of fear. If you look at the losses in the BOB, the loss rate at low altitute is higher than at high.

Mike, the problem with "believeing the pilot who was there" is that you can believe, but it may not be helpful. I can produce endless anadotes conclusively proving that about ANY plane outturned ANY OTHER plane. It is simple, we are reading, hearing the tales of the guys that lived! Not the guys who died getting outturned. A second problem is that they are using vague terms that you may assume means something that it doesn't. A "forinstance" is that to a British pilot "maneuverability" is turn radius at low speed. For a german, it is usally defined as "roll rate and energy". Partly because of the different tactics.

Rocky

And how much time did you spend flying these aircraft to come up with all of that?

Yup, I will continue to believe folks that 1) were there and 2) actually did it. This is true of WWII, AWI and any other period I care about.

You don't fly aircraft that close to the envelope. Too dangerous. Too theoretical. A decent aircraft in the hands of a superior pilot will win far more often than the reverse. ultimately, it is the quality of the pilot that is by far most important.

As a pilot, not in a fighter (my wish but possibly, thank goodness, not realized) I can state there are so many variables that affect flight characteristics that I'm going to side with Rocky on this. It's fine to generlize about aircraft to a point because superior designs coupled with well trained pilots will carry the day. But, if you have triumphed in the skies, whatever the unknowable circumstances, I salute you you for your bravery for joining the battle.

Hi

Mik….I get your combative point, but you disagree with yourself! The superior pilot usualy wins, IF the planes are competitive. If not, say Zekes against Curtiss Hawk III in indochia, no. But you have to know enough about how they work to give your pilot that competitive ride.

As for how I "came up with all of that". Actually in the 80s, it was my job to do analysis of upcoming projects to tell the USAF if the Russians were going to get that competitive aircraft.

Rocky

The 2 foot addition to the FM-2 variant added rudder to the control surfaces, which improved it's turning abilities.

Foot pedals: works rudder for left right turns,
stick: forward / back: works elevators, up / down causes climb or dive
stick left/ right: works alerons for banks.

The larger any surface is in relation to the aircraft size, the more manoverable the aircraft. The Wildcat had a slightly higher glide ratio over most contemporary fighters with the "parachuting" effect of it's mid mount wings, allowing part of the fuselage sides at the wing root to add to the overall area.

With a total difference of 53 MPH at altitude, a celing difference of somthing like 2,000 feet I do not think there was really any practical difference, but I'm no pilot, and not being the man on the spot, I'd guess it was a matter of preference.

The Wildcats were 33 % smaller than the Hellcats, alloeing more storage on the CVE's where they were deployed. I just womnder what that would have done to the Independance class light carriers compliment..

link

link

A couple of links I found..

It is always very interesting to hear the opinions of those who flew the a/c in combat but such memories are often distorted so can be way off.

They were often in a high adrenalin state and it is now 70+ years since the events concerned.

Each pilot only has a limited and small amount of experience to draw on and context is everything. We often lack the context entirely.

… such memories are often distorted so can be way off.

I am reminded of the controversy surrounding the book "The Forgotten Soldier" by Guy Sajer, which arose in the early days of internet chat groups (usenet's soc.hist.war.ww2 and sci.military).

The book is a rather vivid autobiographical account of the experiences of a young man from Alsace (the region of France that has been traded back-and-forth with Germany several times), who wound up in the Grossdeutchland Division in the German Army on the Eastern Front.

Several internet "pundits" asserted that the book was a sham, that there was no such person and the stories recounted were all fabrications. As evidence they pointed out several demonstrably incorrect statements in the book about historically verifiable issues and events.

Then someone asked Mr. Sajer his opinion. He was easy to find, as he still lived in France, was in the phone book, and had for years had a publicly visible career as a graphic designer and cartoonist before writing his book. His reply was worth noting on issues like the discussions above.

He stated quite simply that the points that the pundits pointed out were in fact errors on his part. That he was quite sure his story was rife with errors. That he didn't much care if he remembered correctly which sleeve had the GD emblem on the 1943 tunic, and that if he had said the Tiger tanks rolled down the street when from the historical documents we know there were no Tigers in his area of operation, well as a landser he didn't even know a Tiger from a Panther from a Pz IV, and didn't much care. What he had written were his impressions of the events, filtered through 40 years of telling and retelling the stories to himself in his own mind over and over again.

As any prosecutor or investigator will tell you, never rely on a single eye-witness account to understand a complex, much less a complex AND stressful, event. Multiple witnesses will often give entirely different versions of the same event. But from their perspectives a reasonably accurate impression of the whole can be pieced together.

We process and re-process our memories dozens, hundreds, thousands of times as we store them away for later recall. If we don't, we won't be able to find those memories in the future.

It doesn't mean we should not examine and honor the recollections of "those who were there". It only means we should understand both the emotional strengths and the natural human limitations of individual recollections as we build our understanding of events.

-Mark
(aka: Mk 1)

Good post, Mark.

My father said the FM-2 was tested against captured Zero and turned inside it. I'm thinking he ought to know as he flew all marks of the Wildcat and the Hellcat. He was posted to both Pensacola and the Great Lakes training bases. When the war ended he was in training for night fighter duty. He holds the record for most traps in one day on the paddle wheel steamer training carrier Wolverine, nineteen.

IMHO the Chance Vought F4U Corsair was the best fighter in the PTO.

From memory, in Alfred Price's book "Fighter aircraft"
the FM-2 was a good match for the Zero in the turn, the Zero being slightly better, gaining one turn in eight.
The FM-2 was superior in the roll, the Zero suffering because of higher stick forces. The overall impression was
of equality except at low speeds.

(ie: all aircraft turn at the same radius/rate at a given speed and bank angle)

Well, not quite …

The other variable, beyond speed and bank angle, is wing loading. This is a combination of the amount of lift generated by the airfoil of the wing at the given speed, and how much of that lift is devoted just to fighting gravity (ie: how much lift-generating wing area there is, and how much weight it has to carry).

Once you begin to bank, the lift generated by the wing starts to help you turn. The more lift your wing generates, the more it will help you turn. If you have a surplus of lift, it will help you turn a lot.

As you bank more, you will start to lose altitude but start to turn tighter (you are using less of the lift to keep you up, and more to turn). If you don't want to lose altitude you apply counter-rudder (you steer against the turn with your rudder, which has the effect of keeping your nose up and devoting more of your engine power to fighting gravity), and you lose speed. If the wing's lift is fully utilized just keeping the plane from falling out of the sky, it won't help you turn much -- because if you bank much more you will fall out of the sky.

It is true that all aircraft will have all of these physical forces involved in their turns. It is also true that, prior to G-suites and/or early pressure-assisting suite the G-factors that the pilot could endure were a limiting factor across all aircraft. But it is not true that all aircraft will all turn at the same rate, if they are at the same speed and the same angle of bank.

It is also true that there is no "turn inside" stat. At least, no meaningful "turn inside" stat.

As an example: A B-17 bomber can turn inside an Me-109G fighter.

It is true. The physics all work. The enormous wing area and lift generated by a B-17 works well enough to keep the plane comfortably in the air, with a surplus of lift, at 180mph in the thin air at 25,000 feet. An Me-109 has such a small wing area, which generates much less lift, and must travel at more than 300mph to stay in the air at that same altitude.

A slower plane will have a GREAT advantage in turn rate over a faster plane. The B-17 can turn in a much smaller radius at 180mph than the Me-109 can at 300mph.

So if the B-17 pilot wishes, he can bank his plane over and turn inside an Me-109. If the Me-109 pilot tries to follow the maneuver he will enter a stall, and his plane will fall out of the sky (well, it will fall for a few K feet, which he has easily available, and then recover).

BTW all of this will happen well within the boundaries of sustainable G-forces. Neither pilot will black-out, as they are not pulling high Gs to effect these maneuvers.

But if you walk around telling pilots or historians that a B-17 could turn inside an Me-109 they will call you a fool. Because even if the physics support it, no one cares. It was not a useful way to fly the plane. The time it took you to get the plane into a bank and start using all that wing for a turn made you a sitting duck for a cannon-armed Messerschmidt. And even if he didn't rake you stem-to-stern while you were entering your turn, giving up speed and altitude that you could not easily get back while losing the mutual support of the other planes in the formation (as they continued on the original course) was a recipe for suicide.

Moving back towards the topic …

Yes an FM-2 might have been able to "turn inside" a Zero, if the pilot was willing to give away more speed and altitude than the Zero pilot. But the Zero's wing generated more lift at lower wing loading, so if the Zero's pilot was willing to give away as much speed and altitude he could turn inside the FM-2 (to the limits of both pilots remaining conscious). From that point on, the FM-2 could recover his speed faster (due to his greater engine power), particularly if we was willing to trade away even more altitude by putting his nose down (due to his greater weight). But the Zero pilot could recover his altitude faster (due to his lighter weight and higher lift).

I don't doubt for a moment that the FM-2 could turn inside a Zero if both pilots sustained a speed of >250mph. Almost ANY US fighter could "turn inside a Zero" if you chose a high enough sustained speed for the turn. IF the Zero pilot was not willing to trade away his speed, you could turn inside of him in a P-51, a P-47, a P-40 or a P-38. But the Zero pilot was almost always willing to trade away his speed to the limits of sustainable G-force (the edge of consciousness), and if you tried to fight him on those terms (who will give away the most speed to turn the tightest) you were sure to lose, because his wing contributed more lift to the turning process at any given speed and bank angle, and that advantage grew as the speed fell off, and his speed fell off faster than yours.

-Mark
(aka: Mk 1)

"Well, not quite …"

Yes, totally quite.

"…his wing contributed more lift to the turning process at any given speed and bank angle."

…is false.

OK. Yes, you are correct. My mistake. If we do hold the same bank and speed as constant between two planes, they will turn at the same rate/radius.

The wing which generates more lift allows that plane to bank more sharply at any given speed, without losing altitude. This allows it to make a tighter turn, but not at the same bank as another plane. At the same bank and speed it will turn at the same rate.

I wonder how pilots in combat think on matters like this. If my plane generates more lift than my opponent's, and I put my plane over into a bank (to make a turn), do I pull fewer Gs than I might when I see my nose starting to rise (my plane is generating too much lift to retain constant altitude), or do I bank harder until my nose is not rising?

When I have flown aerobatics (not many times, I assure you!) I don't think I have ever managed to keep a constant altitude in a fast turn. But then neither was that my top concern. When I have flown just for sight-seeing or travel (again, not many times … but more often than aerobatics) I have indeed tried to do "proper" turns keeping speed and altitude constant. It ain't easy, and requires a lot of attention! (At least for a newbie.) I could easily see the finesse abandoned in aerial combat maneuvering.

-Mark
(aka: Mk 1)

(place holder)

The F4F in WW II, by Barrett Tillman calls the FM-2 the wilder Wildcat. There is something to this. In GQ3 for example the FM-2 is given a slightly higher dogfight capability.