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

[Shortround6]

I don't have the precise HP available to a Wildcat at 20,000 or 25,000 ft but I think it was a bit more.

Answered by Mr. Sinclair. You can estimate that the engine will loose about 3 % power per 1000ft.

The Allison was down to about 800hp at 21,500ft without ram.
The Allison could make about 880hp at 19,000ft without ram.
The Wildcat power figures are without RAM.

Well, it's context for comparison with an "Ozhawk". And it sounds like a two speed supercharged version of a Hawk was actually available. I'd love to see some more specific performance stats on it.

Yes the Hawk 75A-4 (Cyclone R-1820-G205) had a two speed supercharger, accounts differ as to the engine making 1000hp at 14,000ft or 15,000ft. The 14,000ft maybe with no ram on an engine test stand.
15,000ft maybe with the airplane flying at/near climb speed?
Speed is in the mid 320mph range at 15,000ft.
Weight of the aircraft is around 5,750lbs for the performance figures as the normal gross weight only included 105 US gallons of fuel, unprotected tanks, little or no armor (how they were flown in India I have no idea).
Since the engine didn't get any better, any combat improvements (protection, better guns, etc) have to be balanced against the loss in performance.

 

[Wild_Bill_Kelso]

Ok, so if I'm reading that right, early Wildcat (F4F-3 and -4 equivalents) could make 1,000 hp at 18-19,000 ft. That is considerably better than what the V-1710-33 or -39 or -73 was making at that altitude. So hopefully this underscores my earlier point; for 'certain' (i.e. higher altitude) bombing raids, the radial engined Wildcat with a 2 speed engine does have more power and probably climbs and maneuvers better at that altitude.

A lot of the fighting in Theater was at lower altitudes but when it came to airfield defense, this was a useful attribute.

Presumably a Mohawk with a two speed engine would also perform a bit better, though the devil is in the details.

Anyone have stats on a late war Mohawk?

 

[Wild_Bill_Kelso]

Answered by Mr. Sinclair. You can estimate that the engine will loose about 3 % power per 1000ft.

The Allison was down to about 800hp at 21,500ft without ram.
The Allison could make about 880hp at 19,000ft without ram.
The Wildcat power figures are without RAM.

Yes the Hawk 75A-4 (Cyclone R-1820-G205) had a two speed supercharger, accounts differ as to the engine making 1000hp at 14,000ft or 15,000ft. The 14,000ft maybe with no ram on an engine test stand.
15,000ft maybe with the airplane flying at/near climb speed?
Speed is in the mid 320mph range at 15,000ft.
Weight of the aircraft is around 5,750lbs for the performance figures as the normal gross weight only included 105 US gallons of fuel, unprotected tanks, little or no armor (how they were flown in India I have no idea).
Since the engine didn't get any better, any combat improvements (protection, better guns, etc) have to be balanced against the loss in performance.

What about this two stage 1830, did they put it in anything?

 

[Shortround6]

he radial engined Wildcat with a 2 speed engine does have more power and probably climbs and maneuvers better at that altitude.

OK, we are getting confused.
The figures for the F4F-3 and F4F-4 are for two stage engines.
The USN didn't get more than a few token F4F-3A's with two speed engines in 1940/41. Until they got the FM-2s with Wright cyclone engines.
The two stage engines require the intercoolers shown in the photos in the earlier post. The two stage engines are around 80-100lbs heavier than an R-1830 with a two speed supercharger (you have to stick a housing with a 2nd impeller on the back of the engine).

What about this two stage 1830, did they put it in anything?

The Hawk 75A-4 used a R-1820.
We do have to keep this straight. R-1820 and R-1830 are totally different engines only thing they have in common is that they are round.
From Wright
You could get R-1820s with single speed supercharger.
You could get R-1820s with two speed superchargers.
You could get R-1820s with single speed superchargers with a Turbo charger added to it (B-17s).

From P & W
You could get R-1830s with single speed superchargers.
You could get R-1830s with two speed superchargers.
You could get R-1830s with two stage superchargers.
You could get R-1830s with single speed superchargers with Turbos added to it (P-43s and B-24s)

Which type of engine from which company are you interested in?
And when?

 

[Wild_Bill_Kelso]

OK, we are getting confused.
The figures for the F4F-3 and F4F-4 are for two stage engines.
The USN didn't get more than a few token F4F-3A's with two speed engines in 1940/41. Until they got the FM-2s with Wright cyclone engines.
The two stage engines require the intercoolers shown in the photos in the earlier post. The two stage engines are around 80-100lbs heavier than an R-1830 with a two speed supercharger (you have to stick a housing with a 2nd impeller on the back of the engine).

Yeah sorry you are right my bad. Just got back from the beach and a long drive. Yes lots of things keep adding more and more weight.

The Hawk 75A-4 used a R-1820.
We do have to keep this straight. R-1820 and R-1830 are totally different engines only thing they have in common is that they are round.
From Wright
You could get R-1820s with single speed supercharger.
You could get R-1820s with two speed superchargers.
You could get R-1820s with single speed superchargers with a Turbo charger added to it (B-17s).

From P & W
You could get R-1830s with single speed superchargers.
You could get R-1830s with two speed superchargers.
You could get R-1830s with two stage superchargers.
You could get R-1830s with single speed superchargers with Turbos added to it (P-43s and B-24s)

Which type of engine from which company are you interested in?
And when?

Whatever has the best performance and as soon as possible. I say we skip the turbos though!

Could the Aussies make two stage R-1830s?

If not maybe just have them make Wildcats. Un-navalized so perhaps a bit lighter. And water injection as soon as it's available.

 

[Wild_Bill_Kelso]

Or presumably by later 1942 two- stage engines could be shipped in to Australia.

 

[Shortround6]

Whatever has the best performance and as soon as possible. I say we skip the turbos though!

Could the Aussies make two stage R-1830s?

If not maybe just have them make Wildcats. Un-navalized so perhaps a bit lighter. And water injection as soon as it's available.

Pratt never used water injection on a R-1830 engine.

It wasn't going to get you a whole lot.

The Wildcat airframe was more sophisticated (harder to build) air frame than the Boomerang. So was the Hawk 75 for that matter.
Un-navalizing things is a whole lot harder than some people think. Yes you can hack saw off the catapult attachment points or the tail hook and leave out the dingy storage.

Now lets look at why the F4F was hundreds of pounds heavier than a Hawk 75.
The F4F was designed to slam onto a flight deck with a vertical speed much higher than the Hawk, (US P-36s had trouble enough landing as it was without buckling the wings).
You had a fair amount of the rear fuselage beefed up to take the arrestor hook without it ripping loose. you had the area between the engine and the cockpit (and wing spar) beefed up to take the impact loads from the landing gear.
You could make things lighter but without going back and recalculating ALL of the loads for each piece and for each assembly you don't KNOW which parts to make thinner and by how much and which parts to leave alone.

Basically about 1000-1050hp at 13,000ft to 15,000ft is as good as it was going to get, The slightly higher HP number at the slightly lower altitude. That is with a two speed supercharger on either engine. Now you have to figure unless you get really advanced engine installation you are going to have around 15-22% more drag than the Allison engine the P-40s. in 1941/42.
Starting figuring out the weapons load and fuel load accordingly.

Nobody mentions the Swedish J22 in these discussions. Yes it was late but it was about as good as you were going to get a R-1830 fighter to perform without a trick supercharger.

or FFVS J 22 - Wikipedia

They got performance by keeping it small (about bf 109 size) and accepted several comprises

They did use plywood over a metal frame.
.

 

[Wild_Bill_Kelso]

I like the J22! Good one to add to the list, though like you said it came a little late. Very nice looking bird.

 

[Wild_Bill_Kelso]

I wouldn't advocate weakening the airframe on a F4F, but removing specific naval gear like the arrestor hook, maybe some extra navigation gear or radios (not sure precisely what it had) and making the wings non-folding ala F4F-3, that would probably save a few hundred pounds. Not sure about the dinghy that probably depends on if you are flying missions over the water or mainly flying CAP (keep it or remove it is probably something you can decide on a per-mission basis). Certainly there seemed to be enough of a difference in performance (mainly due to weight, right?) between F4F-3 and -4 to make a noticeable change (for the worse) that the USN pilots complained about it.

Water injection i understand comes with the R-1820, but if you had that available in time maybe a low-medium alt FM2 type Hawk would also be good.

 

[Wild_Bill_Kelso]

I had no idea the landing gear on the J-22 was like that, weird!

 

[Shortround6]

Water injection i understand comes with the R-1820, but if you had that available in time maybe a low-medium alt FM2 type Hawk would also be good.

The water injection ONLY came "standard" on the FM-2 rather late in production.
Since the FM-2 itself showed up late your FM-2 type Hawk may not show up until the summer of 1944?

The First FM-2 with the Cyclone engine leaves the Factory in Sept of 1943.
Eastern Aircraft builds 310 FM-2s in 1943.

First FM-2s use the -56 engine with 1300hp for take-off at 2600rpm, a totally new engine compared to the older G205 engines.
Wright may be a little off and claims the first -56 engines were produced in Oct of 1943?

The -56W introduced the water injection but Wright says they started delivering them in April of 1944.

Later FM-2s get -56A or -56WA engines with a revised crankshaft that allows 1350hp for take-off at 2700rpm.
But the engines with the revised crankshafts don't show up until Dec 1944.

 

[Farky]

Interesting. To me that may explain why the Mohawk did pretty well in India.

I'd also say the Oscar, though not a fast plane, was a damn good fighter and for an Allied type to hold it's own with a Ki-43 is a positive sign.

Fact that Mohawks did well in India has nothing to do with two-speed supercharger or any performance in high altitude. All encounters with enemy airplanes there were under 10 000 ft, at least in case of Mohawks.
Oscar was good fighter, but every Allied airplane in CBI was able to hold it's own with Ki-43, nothing special there. It was more about tactic (and circumstances) anyway, as soon as Allied pilots realized they can disengage from Ki-43 at will , "greatness" of Oscar was gone.

Are you sure about that timeline? I thought they got K and maybe some M earlier than that

100% sure. 49th FG got some P-40K-1s as reinforcements in October 1942, never Ms. As I wrote, they were still using P-40Es (in mix with P-40Ks) in July 1943 when they replaced them with P-40Ns.

Right, Kittyhawk was faster, for sure, than a Wildcat. But top speed doesn't tell the whole story. At 20,000 feet, per this test, a Kittyhawk I was making 655 hp and rate of climb is 880 fpm. At 25,000 ft, it was making 555 hp and the ROC is down to 480 fpm. ...

Right, with engine running at 2600 rpm and not at 3000 rpm hovewer.

Based on how pilots described it, it's not really capable of combat at 25,000 ft plus, probably not at 20,000 either, or anything over about 15,000 ft.

Combat reports says otherwise. I can agree with 25 000 ft plus, I disagree with the rest.

But over Darwin, fighting at the absolute limit of their performance ceiling, it was literally one pass, split S and dive away, then zoom and climb back up. Because they were just anemic at that altitude.

They were not doing this as only option, but ok. Wildcats over Solomons were doing same thing, because it is smart thing to do. What else can you do with Zeros around?

And it sounds like a two speed supercharged version of a Hawk was actually available.

Of course it was available. Forget producing them, Australia got chance to get them (or at least try to get them) after fall of France in summer 1940. But as I wrote before, nobody in Australia wanted single seat fighters before Pearl Harbor (at least not officialy). RAAF insisted on two seat fighters, that is why they ordered Beaufighters.

Could the Aussies make two stage R-1830s?

They don't even make two speed R-1830s, I already wrote why somewhere in this thread. But sure, why not, yes, everything is possible.

---------------------------------

This is all over the place. Can you please tell me what is your idea of timeline here? When Australia in this "what if" scenario decides about production of this fighter?

 

[GTX]

Nobody mentions the Swedish J22 in these discussions.

Are we giving up on any semblance of practicality in this discussion. The J-22 flew about 4 - 5mths AFTER the CAC Boomerang so why would they consider it?

 

[Shortround6]

Certainly there seemed to be enough of a difference in performance (mainly due to weight, right?) between F4F-3 and -4 to make a noticeable change (for the worse) that the USN pilots complained about it.

They changed more than adding the wing fold. Like changed from 4 guns to six guns but restricted the ammo load. A lot of things got slightly heavier.

In fact the F4F-4 gained about 350lbs empty (doesn't include guns) over the F4F-3 and they took about 90lbs worth of flotation gear.

The wing may have been worth about 200lbs?

However even an F4F-3 with 110 gals of fuel and 300rpg was going to go about 7150lbs.

An F4F-4 with 6 guns and with full internal fuel (144 gallons) was just under 8,000lbs which is were the complaints came from.

 

[Wild_Bill_Kelso]

Fact that Mohawks did well in India has nothing to do with two-speed supercharger or any performance in high altitude. All encounters with enemy airplanes there were under 10 000 ft, at least in case of Mohawks.
Oscar was good fighter, but every Allied airplane in CBI was able to hold it's own with Ki-43, nothing special there. It was more about tactic (and circumstances) anyway, as soon as Allied pilots realized they can disengage from Ki-43 at will , "greatness" of Oscar was gone.

I think that is overstating the case quite a bit, both A6M and Ki-43 were still shooting down Corsairs, P-38s, Kittyhawks, Airacobras, etc. even Hellcats in 1943 and 44. It was nice that it was possible to dive away and extend, (or in the case of a P-38, go into a shallow high speed climb to disengage) and with some types it was certainly easier than others. But there was nothing automatic about it, and in fact the Ki-43 was not as "easy" to dive away from as a Zero since it didn't have the same stiffening of controls in a dive that the Zero did.

Also I'd say that generally speaking, Hurricanes and Airacobras didn't do as well against Ki-43s as some of the other types. That might be a subject for another thread though (and I'm not certain about the Airacobras either).

100% sure. 49th FG got some P-40K-1s as reinforcements in October 1942, never Ms. As I wrote, they were still using P-40Es (in mix with P-40Ks) in July 1942 when they replaced them with P-40Ns.

They didn't get P-40K until Oct 1942 but were using them (with Es) in July 1942?

Right, with engine running at 2600 rpm and not at 3000 rpm hovewer.

Do you have any info on performance at higher RPM at that altitude?

Combat reports says otherwise. I can agree with 25 000 ft plus, I disagree with the rest.

Well what the 'pooped out' altitude actually was, may be up for debate, but I can provide pilot anecdotes and interviews, particularly from the Middle East, noting that the early Kittyhawks weren't much good above 12-15,000 feet (there is some variation of these estimates or comments). The -81 and later engined P-40s with the higher supercharger gear ratio did a bit better, but I think still far from ideal as far as higher altitude.

They were not doing this as only option, but ok. Wildcats over Solomons were doing same thing, because it is smart thing to do. What else can you do with Zeros around?

Several pilots active in SW Pacific noted that they actually could out-turn Zeros at high speed, using what sounds like a low-yo-yo. Generally from all the anecdotes and interviews I've read, it does not sound like they dove away so readily. Navy Wildcats in particular were often trying to use tactics like Thach weave. But I don't think you have enough power to do that at 25,000 feet in a P-40E or K.

There is a level of nuance here, but truly avoiding ALL turning etc. and diving away after a single pass is not what most experienced Allied pilots actually ended up doing, with any aircraft, which is why I say the 49th FG experiences over Darwin were somewhat unique.

When attacking airfields the Japanese bombers tended to usually (not always) fly higher both to make it harder on defending fighters and to avoid some of the flak.

Of course it was available. Forget producing them, Australia got chance to get them (or at least try to get them) after fall of France in summer 1940. But as I wrote before, nobody in Australia wanted single seat fighters before Pearl Harbor (at least not officialy). RAAF insisted on two seat fighters, that is why they ordered Beaufighters.

Well Beaufighters certainly weren't a bad choice.

They don't even make two speed R-1830s, I already wrote why somewhere in this thread. But sure, why not, yes, everything is possible.

---------------------------------

This is all over the place. Can you please tell me what is your idea of timeline here? When Australia in this "what if" scenario decides about production of this fighter?

Obviously it's a 'What if" scenario which some people can find inherently frustrating. It is certainly not something which actually happened. Presumably somebody at RAAF would have had to have a lightbulb go off in their head (which didn't actually happen) probably at a very early date in order to make this come together.

And it didn't actually happen so it can seem like an exercise in futility. Hence the separate area for 'What If' threads.

But in threads like this you often learn a lot of details and nuances about military aircraft from the specific time and place under consideration which is one of the reasons I like them. I have certainly learned a lot in this thread, especially as I didn't know that much in detail about the various Wildcat marks and their engines, the various Hawk marks, the exact differences between the Wright R-1820 and P&W R-1830 and so on (which I still get a bit confused on, I hope you will forgive me).

 

[Wild_Bill_Kelso]

They changed more than adding the wing fold. Like changed from 4 guns to six guns but restricted the ammo load. A lot of things got slightly heavier.

In fact the F4F-4 gained about 350lbs empty (doesn't include guns) over the F4F-3 and they took about 90lbs worth of flotation gear.

The wing may have been worth about 200lbs?

However even an F4F-3 with 110 gals of fuel and 300rpg was going to go about 7150lbs.

An F4F-4 with 6 guns and with full internal fuel (144 gallons) was just under 8,000lbs which is were the complaints came from.

Right.... and I think for SW Pacific a four gun Wildcat is just fine...

 

[GTX]

Obviously it's a 'What if" scenario which some people can find inherently frustrating. It is certainly not something which actually happened. Presumably somebody at RAAF would have had to have a lightbulb go off in their head (which didn't actually happen) probably at a very early date in order to make this come together.

Don't get me wrong, I like what if scenarios (after all I run a forum largely, though not exclusively, dedicated to them). That said, I prefer to see some practicality if proposing things. I would also challenge the comment "have a lightbulb go off in their head (which didn't actually happen)". Quite the opposite in fact. The RAAF and the Australian Govt/industry, actually made very sound decisions in the lead up to the war. Moreover, in terms of aircraft development/production etc they actually achieved near miracles given they were essentially starting from next to nothing in the mid 1930s.

 

[Wild_Bill_Kelso]

Don't get me wrong, I like what if scenarios (after all I run a forum largely, though not exclusively, dedicated to them). That said, I prefer to see some practicality if proposing things. I would also challenge the comment "have a lightbulb go off in their head (which didn't actually happen)". Quite the opposite in fact. The RAAF and the Australian Govt/industry, actually made very sound decisions in the lead up to the war. Moreover, in terms of aircraft development/production etc they actually achieved near miracles given they were essentially starting from next to nothing in the mid 1930s.

I didn't mean that comment (no lightbulb went off) as a general criticism of Australian pre-war planning, just the specific issue of preferring two-seat fighters exclusively as opposed to single seat, which others in the thread have mentioned and I'm taking their word for it.

As for the date(s) of ostensible "Ozhawk" production, first let me say, that I didn't know enough about this going into it to specify a timeline right off the bat, so I'm really kind of fishing for a time frame based on what was possible.

But that said I think I gave a rough outline for that upthread a few posts. I would see it not so much as an either / or (i.e. produce a world class fighter right out the gate) but more of a gradual thing, starting with a basic Hawk, then adding a better engine, maybe another pair of guns, some armor, then SS fuel tanks and maybe a still better engine. This would be with either Australian produced engines or imported ones, as available.

The first perhaps close to the timeline of the Boomerang (maybe that is too ambitious, but as close to it as possible) and then later 'marks' of the Ozhawk as capabilities improved or parts were imported. Anything they made would need to be available in 1942-early 1944 to be of much use. If that kind of timeline is impossible then it is no dice.

Boomerang was first flight in mid-1942 and into combat in 1943, right? I think you could get a Hawk into action about that fast, but maybe not.

 

[Wild_Bill_Kelso]

Fact that Mohawks did well in India has nothing to do with two-speed supercharger or any performance in high altitude. All encounters with enemy airplanes there were under 10 000 ft, at least in case of Mohawks.

What is your source for the operational history of the Mohawk in Burma?

 

[Wild_Bill_Kelso]

The water injection ONLY came "standard" on the FM-2 rather late in production.
Since the FM-2 itself showed up late your FM-2 type Hawk may not show up until the summer of 1944?

The First FM-2 with the Cyclone engine leaves the Factory in Sept of 1943.
Eastern Aircraft builds 310 FM-2s in 1943.

First FM-2s use the -56 engine with 1300hp for take-off at 2600rpm, a totally new engine compared to the older G205 engines.
Wright may be a little off and claims the first -56 engines were produced in Oct of 1943?

The -56W introduced the water injection but Wright says they started delivering them in April of 1944.

Later FM-2s get -56A or -56WA engines with a revised crankshaft that allows 1350hp for take-off at 2700rpm.
But the engines with the revised crankshafts don't show up until Dec 1944.

Well that does sound like water-injection is out of reach timewise, though it might keep an existing Oz-hawk somewhat "in the game" in 1944.