A Radial Engined Fighter for the Australians to build (and maybe the Chinese and Indians)

[GTX]

For a better idea of pre WW2 planning find a copy of Blainey's book on Essington Lewis.

If was not for Lewis, Australia would not have had an aircraft industry or been producing the steels required for not just aircraft but all other weapons and munitions.

View attachment 668505

Have got

 

[Shortround6]

What could an OzHawk bring to the table? Well we don't know for sure because (so far as i know) nobody made a P-36 with SS tanks, four heavy guns, more armor and plumbing for an external fuel tank. So it's not clear how much weight will be added by some more armor and SS tanks, and maybe a couple more guns. But we can get closer to a concrete idea of that, not only from similar planes (including the VL-Myrsky which Shortround6 just linked) but also, there is another thread on this site where something similar to this was debated before and some of the posters there crunched the numbers on the Hawk

You can estimate the weight numbers very easily because the early P-40s were pretty much the P-36 with a different engine in front of the fire wall. I don't know why estimating these numbers seems to be such a problem.

Assuming you could make a roughly 6,000 - 6,500 lb OzHawk, you would have the following traits:

*Faster climbing than a Kittyhawk or (probably) a Wildcat

A lot depends on how you figure climb. Initial climb from sea level for the 1st minute?
Climb for the first 5 minutes? (US standard?)
Climb to 20,000ft?
Climb from sea level to 25,000ft?

Better range / endurance than a Spitfire or P-39

Now it's get dicey because the P-36/Hawk 75 was only supposed to go into combat with 105US gallon on board.
It would 160 gallons in the tanks but that was overload/ferry fuel. So strap your belly tank to the P-39 and check your range.
You also might want to check the Fuel burn of a P-36 or radial engine fighter vs the liquid cooled fighters at given speeds.

http://www.wwiiaircraftperformance.org/P-36/P-36A_38-180_PHQ-M-19-1152-A.pdf

altitude 5,000ft
Plane.......................HP......................Speed mph
P-36.......................1045.........................276
P-36.......................950............................268
P-36.......................850............................258
P-36.......................750............................247

P-40B.....................950...........................307

altitude 15,000
P-36.......................825..............................291
P-36.......................750............................285
P-36.......................650............................272
P-36.......................600............................264

P-40B.....................720.........................310
P-40B....................600..........................286
P-40B.....................480.........................258
P-40B.....................400............................232

We can see the P-40B either can go much faster on the same amount of power or can go the same speed on about 80% of the power.
The Spitfire or the P-39 should do even a bit better for range

*Simpler maintenance than a Kittyhawk, Spitfire, or P-39 (probably, due to air cooled engine)

Rather depends on how much maintenance the cooling system needed, Of course the R-1830 needs 4 extra spark plugs. And unless somebody has the instructions/ time sheets fore the periodic maintenance we are just guessing.

*Less vulnerable engine than a Kittyhawk, P-39 or Spitfire

It didn't happen often but there is a picture of an Allison out of a Tomahawk that took fourteen 7.9mm hits and got the pilot home over North Africa. It doesn't say 5 minutes or 20 minutes. Yes the radial engines had a better reputation but a lot depended on where each engine took the hit's.

If you add the two stage R-1830 it (Pinsog said this improves HP from 625 to 1,000 hp at 20,000 ft) then you can add:

*Much better performance at altitude than a Kittyhawk or P-39

And potentially, you have room to improve the aircraft if / when any kind of improved engines become available.

And here we go back to weird idea that you can just stuff whatever version of the R-1830 in a fighter and it doesn't make any difference to the engine installation.

They were all interchangeable right?
The single speed and two speed engines were interchangeable. May be bit bigger air intake and oil cooler intake but only slightly?

Two stage engine needs around 10 cubic feet of space to house the intercoolers and ducts. It needs over twice the airflow to feed the intercoolers that the engine intake needs.
You need extra cooling airflow for the engine, both engine cooling air and air for the oil cooler.
The two stage engine was heavier by about 800-100lbs? the two stage engine is going to need a bigger propeller to get the best performance.

The Turbo engine needs even more air flow for all three needs. It needs more cubic feet of space for the intercoolers and ducting . And perhaps a bigger prop.

It turns out that while many (but not all) V-12 engines could improved with minor tweaks and improved fuel the radials were nowhere near as easy to work with. They usually demanded much more extensive modifications to the basic structure of the engines.
Yes the got about 25% more power out of the R-2800 in the Thunderbolt but that required
A better fuel.
A turbo charger that could raise the manifold pressure without using (much) crankshaft HP to run the superchargers.
A large intercooler to cooling incoming air.
Water injection to further cool the engine.

Please note that the R-2800 used in the Douglas A-26 bomber was good for 2000hp for take-off but only 1600hp at 13,500ft. The high gear on the supercharger was taking several hundred HP to run so you had a choice. Add hundreds of pounds of superchargers and intercoolers and water injection equipment OR redesign the engine to run at higher RPM.
The C series had new everything, 100rpm faster and had much better cooling and managed 1700hp at 16,000ft when they showed up in late 1944. early 1945. Like the Wright engines they used new cooling fins, new cylinder heads, new crankcases and crankshafts etc. Now scale that back to the R-1830.

 

[Wild_Bill_Kelso]

Well I wasn't thinking of anything so exotic as turbo, but I take your point about the two-stage requiring some space.

Presumably if they could fit it into a Wildcat you could find a way with a P-36, but if not, just make Wildcats.

 

[Farky]

Why not use the R-1830 with the two stage supercharger that the Wildcats had?

Use of two stage supercharger Twin Wasp in Ozhawk means you need much more time for modification of airplane. So, if we want Ozhawk in units in April 1943, we need to start even sooner than in January 1941. And we are talking most likely about months, not weeks. It took Grumman long time to figured out cooling (and others things) of this engine in Wildcat. But we have another problem - at this point this engine is new and is needed for production of F4F-3 for US NAVY. I don't think that USA will approve export to Australia any time soon, even Great Britain did not get Wildcats/Martlets with two stage engines until late 1942 because those engine were not cleared for export sooner (if I remember well).

I would say that the answer to your question (which I bolded above) depends on whether the new aircraft is better than the Boomerang or say, a P-39, if it can work out as a front line fighter? I'd also ask if it introduces any capability that existing fighters don't already have.

We are producing fighters for RAAF, so it really doesn't matter if its better or worse than P-39. It must be somewhat better than Kittyhawk or Spitfire in their roles.

First let's consider an Aus_Wildcat/ Aus_Martlet. If they could produce these, they would have an aircraft with a proven track record of being an effective defender against Japanese raids, and a decent escort fighter to escort both light and heavy bombers as well. No, it isn't as fast as a Kittyhawk or a Spitfire, but it has a better altitude performance than the former and a significantly better range / endurance than the latter. It works well in a Tropical environment and without a radiator, is (arguably) a bit less vulnerable to ground fire etc.

What could an OzHawk bring to the table? Well we don't know for sure because (so far as i know) nobody made a P-36 with SS tanks, four heavy guns, more armor and plumbing for an external fuel tank. So it's not clear how much weight will be added by some more armor and SS tanks, and maybe a couple more guns. But we can get closer to a concrete idea of that, not only from similar planes (including the VL-Myrsky which Shortround6 just linked) but also, there is another thread on this site where something similar to this was debated before and some of the posters there crunched the numbers on the Hawk

In April 1943, you don't need high altitude interceptor to defend Darwin (basically only place in danger from high altitude air raids at this point), you have Wing of Spitfires there and they are doing good job, range is not a concern there (not at this point). Over New Guinea fighting takes place usually at lower altitudes and Kittyhawks are doing good job, range is always issue there. Escort of light and medium bombers is no problem, they handle it just fine. Escorting of heavy bombers in high altitude with anything else than P-38 is just wishful thinking. So to bring something better to RAAF squadrons in combat zones you need fighter with better interceptor capabilities than Spitfire or significantly better range than Kittyhawk.

Ozhawk make sense if we can have them in December 1941, Darwin and Port Moresby (Rabaul, maybe?) are places where fighters can by useful in weeks after PH. It can kinda hold the line until Kittyhawks (and USAAF P-40s and P-39s) arrived. There is no way we can produce them in Australia at this time tho, ordering Hawks 75 from USA is a different story.
Ozcat - same thing, we need them in December 1941 to make sense (at least to me). There was embargo on export of R-1830 engine with two stage supercharger so our Australian Wildcat must be same as Martlet/Wildcat Mk.II or Mk.III if we want R-1830 in this airplane. Performance of Martlets Mk.II/III is very close to Boomerang with the same engine (it shows how good job they did in Australia with Boomerang btw). As with Ozhawk, there is no way we can make Ozcats in time, we can order them from USA and maybe get them before PH but we are not talking about that here.

 

[Shortround6]

And again, timing.................and fat fuselages.

For the P & W R-1830 engines

year................................1940...................................1941...............................1942.......................1943
Two stage.......................98.......................................507.................................2129.......................2926 last built in Aug
two speed.....................1917..................................2862................................1914.......................3752
single speed.................1623.................................3,069.................................6,155.....................4810

Now in 1943 Buick built 24,624 single speed R-1830s and Chevrolet built 23,414 single speed R-1830s.

The P & W test mule (an early P-40) did fit in the two stage engine. They lost two cowl guns, in fact it lost everything in front of the firewall/windscreen.
In may have been the most advanced radial engine plane flying in America at times in 1943. But that is too late for what you want to do.

Some of the labels are wrong, like the top scope looks to be about the size needed for the intercooler/s.
Plane was flying at 7100lbs in late 1942 and at times during 1943 (as late as Oct 22) it had unprotected tanks, no armor, no guns,

P & W estimated that in combat condition with standard equipment and armament it would gross 8300lbs.

 

[Wild_Bill_Kelso]

Use of two stage supercharger Twin Wasp in Ozhawk means you need much more time for modification of airplane. So, if we want Ozhawk in units in April 1943, we need to start even sooner than in January 1941. And we are talking most likely about months, not weeks. It took Grumman long time to figured out cooling (and others things) of this engine in Wildcat. But we have another problem - at this point this engine is new and is needed for production of F4F-3 for US NAVY. I don't think that USA will approve export to Australia any time soon, even Great Britain did not get Wildcats/Martlets with two stage engines until late 1942 because those engine were not cleared for export sooner (if I remember well).

Fair point, but they could start with single stage engines, do what they could with those, and then do more when the two stage engines became available.

We are producing fighters for RAAF, so it really doesn't matter if its better or worse than P-39. It must be somewhat better than Kittyhawk or Spitfire in their roles.

I disagree. The Australians didn't have an infinite number of Kittyhawks or Spitfires and seeing as the US were losing tons of P-39s in action, if the Australians had some more fighters that were even a little bit better than the P-39s, assuming they had pilots to fly them, I believe that could have been significantly helpful. They were all fighting the same enemy side by side (and were eventually under joint command) so IMO it doesn't matter that much who was flying for what nation.

In April 1943, you don't need high altitude interceptor to defend Darwin (basically only place in danger from high altitude air raids at this point),

Are you sure about that? The Japanese didn't send any raids at 20,000 ft or higher against Pt Moresby or Guadalcanal?

you have Wing of Spitfires there and they are doing good job, range is not a concern there (not at this point).

Disagree. The Spitfires did not do so well, and range (or more specifically, endurance) was definitely a major issue.

Over New Guinea fighting takes place usually at lower altitudes and Kittyhawks are doing good job, range is always issue there. Escort of light and medium bombers is no problem, they handle it just fine. Escorting of heavy bombers in high altitude with anything else than P-38 is just wishful thinking.

Again, I'm not so sure about that. I've just been reading the operational history in the New Guinea area and they sent a lot of heavy bomber raids (and recon missions) out at around 20,000 or so, too high for P-40s or P-39s to fight well but not too high for say, Wildcats.

So to bring something better to RAAF squadrons in combat zones you need fighter with better interceptor capabilities than Spitfire or significantly better range than Kittyhawk.

I think in some ways the Wildcats would have been a better interceptor for Darwin than the Spit V was, at least with the tropical gear and at the boost settings they were using, and with all the other trouble they had. I also think given the very short range of the available P-39s something like a Wildcat (or just more Kittyhawks) would have been helpful at Milne Bay and the other South NG bases.

Ozhawk make sense if we can have them in December 1941, Darwin and Port Moresby (Rabaul, maybe?) are places where fighters can by useful in weeks after PH. It can kinda hold the line until Kittyhawks (and USAAF P-40s and P-39s) arrived. There is no way we can produce them in Australia at this time tho, ordering Hawks 75 from USA is a different story.
Ozcat - same thing, we need them in December 1941 to make sense (at least to me). There was embargo on export of R-1830 engine with two stage supercharger so our Australian Wildcat must be same as Martlet/Wildcat Mk.II or Mk.III if we want R-1830 in this airplane. Performance of Martlets Mk.II/III is very close to Boomerang with the same engine (it shows how good job they did in Australia with Boomerang btw). As with Ozhawk, there is no way we can make Ozcats in time, we can order them from USA and maybe get them before PH but we are not talking about that here.

I think these aircraft could have been useful in 1943, and I'm not convinced that a Martlet II or III is equivalent to a Boomerang in terms of performance. Maybe we should take a closer look at that.

 

[Wild_Bill_Kelso]

And again, timing.................and fat fuselages.

For the P & W R-1830 engines

year................................1940...................................1941...............................1942.......................1943
Two stage.......................98.......................................507.................................2129.......................2926 last built in Aug
two speed.....................1917..................................2862................................1914.......................3752
single speed.................1623.................................3,069.................................6,155.....................4810

Now in 1943 Buick built 24,624 single speed R-1830s and Chevrolet built 23,414 single speed R-1830s.

The P & W test mule (an early P-40) did fit in the two stage engine. They lost two cowl guns, in fact it lost everything in front of the firewall/windscreen.
In may have been the most advanced radial engine plane flying in America at times in 1943. But that is too late for what you want to do.

View attachment 668781

Some of the labels are wrong, like the top scope looks to be about the size needed for the intercooler/s.
Plane was flying at 7100lbs in late 1942 and at times during 1943 (as late as Oct 22) it had unprotected tanks, no armor, no guns,

Wow, that is super cool, and interesting. It's the Ozhawk, basically, though as you say, lacking armor and guns.Is that a model or the real thing?

I'll grant you it does seem heavier than I was thinking, but even with SS tanks and armor and a couple of guns, I'm not sure you are still not really flirting with Kittyhawk type weight.

P & W estimated that in combat condition with standard equipment and armament it would gross 8300lbs.

A good engineer needs to look closely at the design and figure out how to drop some weight, I think they could do better than that.

 

[Wild_Bill_Kelso]

If it's impossible to get the weight down on the 2-speed Hawk, then the optimal solution may be to just built Wildcats, since Grumman seems to have somehow fit everything in for ~ 1,000 lbs less weight

 

[Shortround6]

A good engineer needs to look closely at the design and figure out how to drop some weight, I think they could do better than that.

If it's impossible to get the weight down on the 2-speed Hawk, then the optimal solution may be to just built Wildcats, since Grumman seems to have somehow fit everything in for ~ 1,000 lbs less weight

Be very careful with the weights of both planes.

A 7150lb F4F-3 had 300rpg (4 guns) and 110 gallons of fuel and 68lbs of oil.
A 7543lb F4F-3 had 430rpg (4 guns) and 147 gallons of fuel and 82.5lbs of oil.
A 7972lb F4F-4 had 240rpg (6 guns) and 144 gallons of fuel and 82.5lbs of oil.

The 7150lbs Hawk 18 Special and no guns/ammo but did include a 200lb pilot and a an undisclosed amount of fuel. 120 gals?
At 8300lbs the plane may have included armor, several hundred pounds of protected fuel tanks. A P-40 with six guns was carrying 470-480lbs of guns and 423lbsof ammo.
Full fuel (internal) may have added 170-220lbs of fuel.

You could have cut weight by using just 4 guns and limited ammo (and tossed out one fuel tank) in the Hawk special. Just like some of the P-40L's and N's.

Also be careful what you may wish for, you just might get it.
Later P-40s carried a very impressive bomb load.
Later Wildcats (FM-2s) could carry a pair of 325lb depth charges or 250lb bombs.

 

[Farky]

@ Wild_Bill_Kelso - we can talk for a long time about Spitfires over Darwin, discuss if issue was range, tactic or commander. We can also discuss operation I-Go and other stuff, altitude of air raids and what was happenning there. I can even show you combat reports of Kittyhawks successfuly intercepting raids in 20 000 ft + over New Guinea during 1942-43 (just so you can promptly reject them). Let's not do that, we both know we will never agree and all of this is really not important because at the end of the day you do not have airplane you think you have. There is no way you can produce Wildcat or Hawk in Australia with two stage supercharger engine in spring 1943 unless you "bend" history even more. Which you can do of course, this is "What-if" after all.

I think these aircraft could have been useful in 1943, and I'm not convinced that a Martlet II or III is equivalent to a Boomerang in terms of performance. Maybe we should take a closer look at that.

I agree, these aircrafts could have been useful in 1943 - in exactly same roles (and units) as Boomerang.

Martlet/Wildcat II with six guns was almost identical with Boomerang in performance. Same airplane with four guns (most likely without armor and/or SS fuel tanks but I am not sure about that) was faster and climbed better than Boomerang. Martlet/Wildcat III with four guns was faster by few mph and climbed better. Maybe you have different numbers, I don't know.

 

[Wild_Bill_Kelso]

Be very careful with the weights of both planes.

A 7150lb F4F-3 had 300rpg (4 guns) and 110 gallons of fuel and 68lbs of oil.

I think this is good!

A 7543lb F4F-3 had 430rpg (4 guns) and 147 gallons of fuel and 82.5lbs of oil.

This is still good!

A 7972lb F4F-4 had 240rpg (6 guns) and 144 gallons of fuel and 82.5lbs of oil.

This is a little too heavy!

The 7150lbs Hawk 18 Special and no guns/ammo but did include a 200lb pilot and a an undisclosed amount of fuel. 120 gals?
At 8300lbs the plane may have included armor, several hundred pounds of protected fuel tanks. A P-40 with six guns was carrying 470-480lbs of guns and 423lbsof ammo.
Full fuel (internal) may have added 170-220lbs of fuel.

I think six guns and the extra strong wings of a P-40, 160 gallons of fuel and so on, is too much for what you have convinced me is a fairly low-powered engine that cannot be made more powerful quickly. But we know that the four gun F4F-3 performed quite well.

You could have cut weight by using just 4 guns and limited ammo (and tossed out one fuel tank) in the Hawk special. Just like some of the P-40L's and N's.

Also be careful what you may wish for, you just might get it.
Later P-40s carried a very impressive bomb load.
Later Wildcats (FM-2s) could carry a pair of 325lb depth charges or 250lb bombs.

I love the P-40 but I think the Wildcat could do a few things better - like fight up a bit higher.

I should clarify that though, because I obviously don't mean legit 'high altitude' - No Wildcat is going to fight well at 35,000 ft. You want a P-47 for that.

Maybe we can call 0-8000 ft low altitude, 8-15000 medium altitude, 15-25 high, and 25-35 very high. I see the Wildcat and possibly an Ozhawk working out better in that third altitude band, and maybe has a little bit more pep in the lower part of the fourth.

 

[Wild_Bill_Kelso]

@ Wild_Bill_Kelso - we can talk for a long time about Spitfires over Darwin, discuss if issue was range, tactic or commander.

Oh, I've read a lot about it and we might not be as far apart as you seem to assume. There were many factors. I understand why Caldwell made the tactical decisions he did, but it wasn't right for the Theater. There was the boost setting being used, the specific engine used, there were major issues with Australian manufactured ammunition, issues with guns freezing (heaters not set up right) engine problems, hydraulic problems, and other issues. But for sure, endurance of the Spit Mk V was one of the problems. And from that time the Spitfire did not (IMO) have a major role in the fighting in the SW Pacific, unless there are some combat encounters I missed (which I won't deny is possible!)

We can also discuss operation I-Go and other stuff, altitude of air raids and what was happenning there. I can even show you combat reports of Kittyhawks successfuly intercepting raids in 20 000 ft + over New Guinea during 1942-43 (just so you can promptly reject them).

Again, don't be so sure. I know that P-40s intercepted raids at that altitude and higher. I know for example that the 49th FG did fairly well with P-40s defending Darwin against raids in the 22-28,000 ft range, and managed to shoot down nineteen Japanese aircraft including twelve bombers, mostly G4M, for the loss of nineteen fighters. Partly the losses were due to most of the pilots being very green. Partly the relative success was due to their excellent leadership. But they did prove that even the early P-40E could do the job, with the right tactics.

The USAAF 49th Fighter Group over Darwin: a forgotten campaign | The Strategist

This year has seen many 75th anniversaries of battles and campaigns from the darkest hours of 1942, with the Battle of the Coral Sea (4 to 8 May) prominent. But in all these commemorative activities ...

www.aspistrategist.org.au

I just think something like a Wildcat would have worked out a little bit better for that specific mission. I think even early Kittyhawks were very good fighters, properly utilized. But any fighting above 15,000 or so was not ideal for that aircraft, IMO.

For example, B-24s crews in the SW Pacific complained that Kittyhawks were all but useless as escorts because they couldn't perform at higher altitudes where the Liberators liked to fly. When the Liberators climbed the Kittyhawks were left behind. And these were the later mark Kittyhawks with the higher gear ratio in the supercharger.

Let's not do that, we both know we will never agree and all of this is really not important because at the end of the day you do not have airplane you think you have. There is no way you can produce Wildcat or Hawk in Australia with two stage supercharger engine in spring 1943 unless you "bend" history even more. Which you can do of course, this is "What-if" after all.

What do you think was the earliest they could do it? I don't want to bend things too far.

I agree, these aircrafts could have been useful in 1943 - in exactly same roles (and units) as Boomerang.

Martlet/Wildcat II with six guns was almost identical with Boomerang in performance. Same airplane with four guns (most likely without armor and/or SS fuel tanks but I am not sure about that) was faster and climbed better than Boomerang. Martlet/Wildcat III with four guns was faster by few mph and climbed better. Maybe you have different numbers, I don't know.

Well here is something we can sink our teeth into. I believe the F4F-3 Wildcat (not sure if there was an exact UK equivalent) was substantially better at air to air combat than a Boomerang, overall. However F4F-3 is, as i understand it, equipped with a two stage R-1830. And with a single stage engine, Wildcat is probably closer to a Boomerang (still a bit better in the fighter role, I think, but closer).

So maybe the scenario is they start out about the same as Boomerangs, but as soon as the two stage engine version is available, it's clearly better and certainly can be used at the tip of the spear to confront IJN and IJA raids, to escort Allied bombers on their own raids and recon missions, etc. Wildcats definitely did as well as Army types in the Solomons.

 

[Farky]

What do you think was the earliest they could do it? I don't want to bend things too far.

Honestly I have no idea. It depends on lot of things - when you have engine available, how much airplanes from initial batch (order) you still need to build at this point etc. I have no clue when was export embargo on Twin Wasp with 2 speed 2 stage supercharger lifted. Great Britain did get first two Wildcats with this engine at the very end of 1942 so embargo must be over for some weeks or rather months at this point.
Ozhawk with this engine is a dead end in my opinion, even if you start development of this version pretty early (let's say summer 42). It can took you more then a year to make it work and the outcome is very uncertain. Ozcat is a different story, you do not need to develop anything, Grumman did it for you.

My guess is that you can probably have Wildcats with 2 stage R-1830 build in Australia with operational units somewhere around beginning of 1944 or near the end of 1943, if you are producing Wildcats before. But than again, ordering them from USA is faster and cheaper, there is no need to produce fighters if you can just buy them (or even better get them via Lend Lease).

Well here is something we can sink our teeth into. I believe the F4F-3 Wildcat (not sure if there was an exact UK equivalent) was substantially better at air to air combat than a Boomerang, overall. However F4F-3 is, as i understand it, equipped with a two stage R-1830. And with a single stage engine, Wildcat is probably closer to a Boomerang (still a bit better in the fighter role, I think, but closer).

F4F-3 was much better fighter than Boomerang, no doubt. UK equivalent is Wildcat V, kinda, these were in fact FM-1s (airplanes pretty close to F4F-3).

Wildcat with a single stage Twin Wasp engine with 6 guns is not better or worse than Boomerang. These were Martlets/Wildcats II in UK.

Martlet II, 6 guns, R-1830-90 (S3C4G, exactly same engine is in Boomerang) -
Weight 7745 lbs
Maximum speed - 292 mph@6000 ft, 300 mph@14 000 ft
Rate of climb S.L. (normal) - 2030 fpm

http://www.wwiiaircraftperformance.org/f4f/wildcat-II-ads.jpg

Boomerang, R-1830-90 -
Weight 7730 lbs
Maximum speed - 295 mph@5000 ft, 300 mph@15 000 ft
Rate of climb S.L. (normal) - 2050 fpm
Source - NAA, various documents

Wildcat with a single stage Twin Wasp engine with 4 guns is better than Boomerang, slightly faster, better climb. These were Martlets/Wildcats III in UK.
Martlet III, 4 guns, R-1830-90 -
Weight 7200 lbs
Maximum speed - 297 mph@6000 ft, 307 mph@14 000 ft
Rate of climb S.L. (normal) - 2400 fpm

http://www.wwiiaircraftperformance.org/f4f/wildcat-III-ads.jpg

There was a batch of 10 airplanes ordered as Martlet II with 4 guns, they were later marked as Martlet III. They were apparently little bit faster for some reason.
Martlet II/III, 4 guns, R-1830-90 -
Weight 7255 lbs
Maximum speed - 317 mph@14 000 ft
Rate of climb S.L. (normal) - n/a

http://www.wwiiaircraftperformance.org/f4f/martlet-II-ads.jpg

There were also Martlets I and IV (with single stage two speed Wright Cyclone engines), Martlet I was better than Boomerang, Martlet IV was worse.

http://www.wwiiaircraftperformance.org/f4f/martlet-I-ads.jpg

http://www.wwiiaircraftperformance.org/f4f/wildcat-IV-ads.jpg

I wrote this before - kudos to Fred David and CAC. They were able to develop and produce fighter plane which was just as good as Wildcat with same engine in incredibly short time.

So maybe the scenario is they start out about the same as Boomerangs, but as soon as the two stage engine version is available, it's clearly better and certainly can be used at the tip of the spear to confront IJN and IJA raids, to escort Allied bombers on their own raids and recon missions, etc. Wildcats definitely did as well as Army types in the Solomons.

From late summer 1943 onwards IJN/IJA raids are less and less concern, you are on ofensive and what you really need is range. At this stage of war you can have as much P-40s as you want and they are good enough. Sure,they cannot escort heavy bombers in very high altitude but that is job for USAAF Lightnings, not for P-40s. And altough Wildcat is good at high altitude, it isn't that good it can escort B-17s or B-24s there (not to mention the range). My point is still the same - Wildcat (or Ozhawk) do not bring anything special (unique) to RAAF in 1943 so why bother with production?

Boomerang was not as much about performance anyway, but that is rather long (and well known) story.

 

[EwenS]

There is an explanation of the various FAA Martlets and their distinguishing features here.

The Grumman Wildcat in FAA Service by Bruce Archer

The Mark I and III (both the 10 relabelled Mk.II and 30 ex-Greek Mk.III) had fixed wings.

 

[Farky]

There is an explanation of the various FAA Martlets and their distinguishing features here.

The Grumman Wildcat in FAA Service by Bruce Archer

Great article, however informations about first batch of Martlet II (10 airplanes with fixed wings, AM954 - AM963) are not quite correct in my opinion. They were not powered by two stage Twin Wasps (R-1830-76) but with single stage version (R-1830-90). Picture of AM958 is showing lack of typical small bulge covering intercoolers close to wing leading edge. Also Pilot Notes for Martlet II is talking about specific differences between AM954 - AM963 and the rest of Martlets II, nothing about having different engine is mentioned there.

The Mark I and III (both the 10 relabelled Mk.II and 30 ex-Greek Mk.III) had fixed wings.

You are right.
I really wonder what airplane is this - http://www.wwiiaircraftperformance.org/f4f/martlet-II-ads.jpg . Martlet II with four guns and folding wings should not exist and yet here we are.

 

[EwenS]

Great article, however informations about first batch of Martlet II (10 airplanes with fixed wings, AM954 - AM963) are not quite correct in my opinion. They were not powered by two stage Twin Wasps (R-1830-76) but with single stage version (R-1830-90). Picture of AM958 is showing lack of typical small bulge covering intercoolers close to wing leading edge. Also Pilot Notes for Martlet II is talking about specific differences between AM954 - AM963 and the rest of Martlets II, nothing about having different engine is mentioned there.

View attachment 669385



You are right.
I really wonder what airplane is this - http://www.wwiiaircraftperformance.org/f4f/martlet-II-ads.jpg . Martlet II with four guns and folding wings should not exist and yet here we are.

ISTR in one discussion about the Martlets that sailed to the Indian Ocean on Illustrious in early 1942, there was one that was converted on the ship from fixed to folding wings after being involved in a deck landing accident. Probably a Mk.I. Something else that wasn't supposed to have happened. I'll try to remember where I saw it and post the details.

 

[Geoffrey Sinclair]

British Martlet according to the USN
Martlet I, ex French order F-292, Wright GR-1820-G205A-2
Martlet II/F4F-3/G-36B, order A-1548, P&W R-1830-S3C4G
F4F-3A (Greek Order), from USN order 75736, P&W R-1830-90, became Martlet III (April 1941)
Martlet IV/F4F-4B, order LL-83734, Wright R-1820-G205A furnished by Britain.

RAF Contract cards agree with the engine types for Martlet I and II.

USN orders,
68219, 8 August 1939, F4F-3, P&W R1830-76, plus 1 X4F-4 with the same engine, 2 XF4F-5 with Wright R-1820-40 and 1 F4F-6 with P&W R-1830-90
75736, 5 August 1940, F4F-3 with P&W R-1830-76/86, F4F-3A with P&W R-1830-90, F4F-4 with P&W R-1830-86, F4F-7 with P&W R-1830-86
99340, 16 May 1942, F4F-4 with P&W R-1830-86, XF4F-8 with Wright R-1820-56

Order 68219 F4F-3 production ended in February 1941, order 75736 F4F-3A production March to May 1941, F4F-3 production from May 1941. Martlet II Order, 10 in March 1941 (became mark III), then June on. So were the first 10 of the Martlet II order F4F-3A or a hybrid with fixed wings and the P&W R-1830-76, -86 or S3C4G?

99036, 18 April 1942, FM-1 with P&W R-1830-86
99340, 16 May 1942, FM-2 with Wright R-1820-56/72W in 1943, -72W only in 1944
227, 31 December 1943, FM-2 with Wright R-1820-72W

The contract for 3 XF2M-1 dated 31 October 1944, for 3 aircraft, cancelled.

 

[Farky]

Order 68219 F4F-3 production ended in February 1941, order 75736 F4F-3A production March to May 1941, F4F-3 production from May 1941. Martlet II Order, 10 in March 1941 (became mark III), then June on. So were the first 10 of the Martlet II order F4F-3A or a hybrid with fixed wings and the P&W R-1830-76, -86 or S3C4G?

Hybrid in my opinion. Fixed wings with four guns in batch AM954 - AM963 are mentioned in Pilot's Notes for Martlet II (AP2031B), at the same time there is not a word about P&W R-1830-76 or -86, only about R-1830 S3C4-G.

 

[nuuumannn]

But the reason I draw the conclusions I have (just like many other people), is because of the operational histories and pilot testimonies. RAF, RAAF, USAAF etc. concluded that the Hurricane was much slower, and in fact too slow for use as a fighter in the Middle East, which was why it was replaced in multiple squadrons by the P-40 in 1941 and 1942.

Cool story. Not true. Hurricanes were NOT replaced by P-40s in the Middle East, supplemented, but not entirely replaced by. The RAF kept several Hurricane Squadrons alongside its Kittyhawk units, Hurri IIcs were extensively used as tank busters and ground attack fighters in the Desert Air Force. The Hurricane was never replaced by P-40s in the CBI either.

Wikipedia is usually wrong mate.

But not always as the info pulled can be verified, as I did. As usual, you're not reading the source material.

As for the claim that the Hurri IIc was faster than the P-40E, yup, there were individual cases where it was, so it does count for something and as always, charts and figures don't always tell the whole story. I posted an example of a Hurri IIc that had a demonstrably slower max speed under trial than a Hurricane I (306 mph), yet its maximum speeds were rated as being higher than that...

Your points are interesting reading though, Bill.

 

[Wild_Bill_Kelso]

Cool story. Not true. Hurricanes were NOT replaced by P-40s in the Middle East, supplemented, but not entirely replaced by. The RAF kept several Hurricane Squadrons alongside its Kittyhawk units, Hurri IIcs were extensively used as tank busters and ground attack fighters in the Desert Air Force. The Hurricane was never replaced by P-40s in the CBI either.

You are arguing with something I didn't say. I never claimed it was replaced across the board, in all units and for every purpose. Look at the passage from my post that you yourself quoted, I will bold part of it to assist in parsing it:

it was replaced in multiple squadrons by the P-40 in 1941 and 1942.

For example,
112 RAF switched from Hurricane to Tomahawk starting in July 1941
260 RAF switched from Hurricane to Tomahawk in Feb 1942, and Kittyhawk starting that same month
3 RAAF switched from Hurricane to Tomahawk in 1941

I would actually go a bit further to say that by late 1941 the P-40 had begun to replace the Hurricane as the main British air superiority fighter in the Western Desert, and within a couple of months of 1942 that process was basically complete. The P-40 in turn began to take a back seat to Spitfire Mk V by the middle of 1942 but as the Spitfire units came in rather slowly, that process took a bit longer and many P-40 units were still fighting as front line escort fighters and etc. well into 1943 and even 1944 (by the Americans).

I agree the Hurricane was not replaced by the P-40 in the CBI, I don't think the P-40 was used by the British in the CBI. For the Americans it was by far the most important fighter in that Theater and I know that the US units which made the most use of it, had outstanding combat records (notably the 23rd Fighter Group).

But not always as the info pulled can be verified, as I did. As usual, you're not reading the source material.

You can accuse me of many things, but not reading the source material isn't one of them.

As for the claim that the Hurri IIc was faster than the P-40E, yup, there were individual cases where it was, so it does count for something and as always, charts and figures don't always tell the whole story. I posted an example of a Hurri IIc that had a demonstrably slower max speed under trial than a Hurricane I (306 mph), yet its maximum speeds were rated as being higher than that...

Well apparently with the Desert gear it was barely able to make 300 mph, as I showed in the links I posted way upthread. Again I've yet to read a single pilot claiming that the Hurricane was faster than the Kittyhawk or Tomahawk and can cite several who indicate the opposite. If you really want to contest this we should start another thread for it.

Your points are interesting reading though, Bill.

Thank you. I've found many of your various posts around this forum also quite interesting as well.