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

Shortround6 said:

Well Curtiss was flying both the H75Q demonstrator and the CW-21 demonstrator in front of Chinese officials in several different Chinese cities in Feb and March of 1939.
They should have had some idea of what they were buying.

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They should - but the original comment was...

I would think the easiest to produce would be the Curtiss P-36.

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I don't believe that's true

The Chinese wound up buying both although the CW-21 was in much smaller numbers.
The Chinese may have wanted the bigger aircraft (the Hawk 75) because of its heavier weapons load?
The H75Q had been equipped with not only the 23mm cannon but with underwing racks for ten 30lb bombs and a fuselage rack for a 500lb bomb.

Clayton Magnet said:

I would say this is about as far as you could take the P-36 design...

View attachment 666741

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Well, it you squint real hard and allow the tin knockers a little more latitude you can get to here.


See, see, the vertical fin and rudder sort of looks like a P-36......................from this angle.........................if the light isn't real good............................if................if......................

Shortround6 said:

See, see, the vertical fin and rudder sort of looks like a P-36......................from this angle.........................if the light isn't real good............................if................if......................

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Empennage looks more like a Ki-61 than a P-36....
but its dark here

Clayton Magnet said:

Empennage looks more like a Ki-61 than a P-36....
but its dark here

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It is the bubble canopy that throws things off.

See, a new wing, new landing gear, new engine, mostly new fuselage but we can still trace it back to the P-36 start of development

And that bird looks uncannily like a Ki-100. Maybe Curtis and Kawasaki were sharing notes?

FLYBOYJ said:

Well if you're talking about construction from the factory or assembly from a kit, it's apples and oranges and even then the CW-21B looks a lot less complicated than a P-36. If we can relay on the accuracy of the many cutaway drawing of both aircraft, the CW-21 looks like a toy compared to the P-36.

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The CW-21's tail look more fragilely connected than a Curtiss XP-31's.

Admiral Beez said:

The CW-21's tail look more fragilely connected than a Curtiss XP-31's.

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I thought I was the only one who thought that. The empennage just looks to me incapable of staying connected during violent maneuvers.

SaparotRob said:

I thought I was the only one who thought that. The empennage just looks to me incapable of staying connected during violent maneuvers.

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Admiral Beez said:

The CW-21's tail look more fragilely connected than a Curtiss XP-31's.

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Looks can be deceiving! Although I wouldn't consider the CW-21 "structurally robust," it was capable of some aerobatic maneuvers.

I have a very old Air Enthusiast (1981) that has a lengthy article on the CW-21. On paper it looked very capable. The article mentions demonstration flights in China in the presence of Chennault. Curtiss test pilot Bob Fausel flew mock combat against a I-15 biplane and the CW-21 outmaneuvered the I-15. It seems the biggest obstacle the Chinese faced with purchasing the CW-21 was the cost.

Shortround6 said:

I get tired of "what ifs" that act like the P-36 was a separate "design" than the P-40.
From the firewall back they were the same aircraft so it is pretty easy to figure out the "development" path.
Throw in the Export Hawk 75s and you can fill in some of the gaps between the US P-36 and the P-40.

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My point was that the aircraft was to be built in Australia.

Australia was already producing, or on the way to producing, the R-1830.

The logical step in development of the P-36 is the P-40, but without a domestically produced V-12 it would be difficult for Australia to build the P-40. Australia would need to import V-12s from either Allison, Packard or Rolls-Royce.

But when will they be getting these engines? About the same time as those arriving for Mustang production?

wuzak said:

My point was that the aircraft was to be built in Australia.

Australia was already producing, or on the way to producing, the R-1830.

The logical step in development of the P-36 is the P-40, but without a domestically produced V-12 it would be difficult for Australia to build the P-40. Australia would need to import V-12s from either Allison, Packard or Rolls-Royce.

But when will they be getting these engines? About the same time as those arriving for Mustang production?

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Basically Australia, had they taken the P-36 route, would have been stuck making some sort of P-36 clone.
If they started earlier than the Boomerang they might have gotten them into service about the same time.
The airframe was more complex than the Boomerang airframe. How much stuff/parts were borrowed from the Wirraway I don't know or if it was just basic construction. But the people in Australia thought the Boomerang was going to be their best bet to get something into production.
Now maybe if they had started 6 months to year earlier they might have been able to get the P-36 into production.
Problem is that some people don't want to settle for a P-36. Or a P-36 with different guns or with a different bombload or a bit better protection.
They want to use the R-1830 engine, which was a logical choice, but then use a non standard installation that the P-36 only used in prototype form. And they want to use a number of other "improvements" to get a significantly better P-36. Which is going to add development time. Which Australia doesn't have.
My point is that even with the P-36 airframe and using the standard R-1830 engines we know what most of the changes are going to be. We know what Changing the guns to Tomahawk standard is going to cost or changing to four .50 cal guns or several other combinations. We know what improved fuel tank protection is going to cost. We know what protection on the P-40 level is going to cost and so on down the line. Cost meaning weight so we can estimate the weight of changes pretty darn well.
If somebody wants to propose turbo charged P-36s with six .50s flying over Darwin we can actually estimate the weight pretty well. It is going to be very close to the weight of the P-40 with some allowance for the different engines. It is the thinking that if they start with a P-36 they will get a lighter, more maneuverable airplane or have some other advantage that bothers me.
Radial engine installations did get better over time. But they didn't get better in the time Australia needs.
P&W did make a much better installation than the one used in the F4F but they didn't get it done until the end of 1942 or early 1943 and fully sorted out. Which is a bit late for Australia, it was even late for the US. An R-1830 powered P-40 that could do 370mph at over 20,000ft might have been very interesting but it wasn't going to show up until late 1943. At which point what are you going to do with it?

For Australia any " improvement" to the P-36 like changes to landing gear or changing to a bubble canopy or trying to engineer a better engine installation is going to delay the project.

I also wonder about the worth of some of the improvements. The P-40 landing gear was not ideal but was it really that bad? It certainly looks clunky but a Tomahawk with a 1040hp engine was only a few mph off the speed of a Spitfire MK II. at 15,000ft. The Spit went faster higher up but the Merlin gave more power higher up. I am just trying to figure out the drag. Playing with the landing gear on a P-36/P-40 when the P-40 wing/landing/fuselage is already as good or slightly better than a Spitfire seems to be pretty far down on the list.
Much like everybody "knew" that if they put full wheel covers on the Spitfire it would go faster but there was always something else that needed doing first.

wuzak said:

My point was that the aircraft was to be built in Australia.

Australia was already producing, or on the way to producing, the R-1830.

The logical step in development of the P-36 is the P-40, but without a domestically produced V-12 it would be difficult for Australia to build the P-40. Australia would need to import V-12s from either Allison, Packard or Rolls-Royce.

But when will they be getting these engines? About the same time as those arriving for Mustang production?

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Australia would need to import engines for fighters anyway, it was indeed already producing the R-1830 but version with single speed single stage supercharger. Even R-1830 engines for Boomerang were imported variant (with two speed supercharger), originally ordered for Beauforts. Australia has rejected the transition of production to R-1830 with two speed (and/or two stage) supercharger, they never "upgraded" to better version.
What is it mean? P-36 with R-1830 Made in Australia will be barely on the same level as Boomerang, maybe even worse. P-36 with imported engines is slightly different story, but you need imported engines in any case.

So, if engine for figher must be imported, why not just go with Allison powered P-40? Altough Twin Wasp was probably easier to obtain than V-1710, but who knows.

Shortround6 said:

Basically Australia, had they taken the P-36 route, would have been stuck making some sort of P-36 clone.
If they started earlier than the Boomerang they might have gotten them into service about the same time.
The airframe was more complex than the Boomerang airframe. How much stuff/parts were borrowed from the Wirraway I don't know or if it was just basic construction. But the people in Australia thought the Boomerang was going to be their best bet to get something into production.

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It's also a fact that Australia's aerospace industry was still in its infancy having only really been established in the 5yrs or so leading up to the war. And I'm not talking about just aircraft design/construction but all the supporting elements including skilled tradesmen, toolmakers, metal producers, sub-component producers etc etc. The reason why the North American NA-16/CAC Wirraway was selected as a starting point was because it was probably the most that Australia could aim for from an essentially standing start and yet still have something practical/useful. Expediency also then led to one using it as the basis for any domestic fighter production (i.e. the CAC Boomerang). To try to introduce something totally different in the timeframe would have either necessitated overseas purchase (i.e. P-40), or totally disruption to the Wirraway line which would have then resulted in even less being available.

Wild_Bill_Kelso said:

You already said things like "a hurricane is faster than a Kittyhawk" etc. which are patently false. Really easy to verify.

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I think the problem here is that you refuse to see anything that contradicts your point of view, Bill. In fact, this twisting of my statement is an example of that. I was specifically referring to the P-40E versus the Hurricane IIc, which, if you'd read it properly, you'd know. So, let's look at what's on offer, shall we?

Peter Bowers in Curtiss Aircraft 1907-1947 (Putnam, 1987) offers a maximum speed for the P-40E (based on Curtiss supplied figures) at 334 mph at 15,000 ft.

Frank Mason in Hawker Aircraft since 1920 (Putnam, 1991) offers a maximum speed for the Hurricane IIc as 336 mph without a corresponding altitude, but Owen Thetford in Royal Air Force Aircraft since 1918 (Putnam, 1987) offers the Hurricane IIc's maximum speed as 339 mph @22,000 ft, which is a significantly higher altitude at which it achieves its maximum as well, and given that the Hurricane IIc was lighter than the P-40E, you can guarantee it's gonna get to altitude faster (you can find this data by looking instead of presuming). Thetford doesn't offer speed for the Kittyhawk I or Ia, which was equivalent to the P-40E.

Now, let's look at easier accessible source material, like Wikipedia, which tells us that the P-40E's maximum speed is 334 mph at 15,000 ft (the same as above since the source is the same) and for the Hurricane IIc is 340 mph @ 21,000 ft, from Jane's Fighting Aircraft of World War Two.



So, get your facts right.

Carry on now...

P-40E numbers are all over the place. You can find about 30mph difference in top speed depending on which books/articles you read.

Anywhere from 366mph to the low 330s.

You can find several tests that confirm the mid 330mph speeds.
However you can also find a few tests that indicate or hint at higher speeds.
You can also find one test that says 361.5mph at 15,000ft.

For some reason many of the US tests are not done at an altitude that makes sense for max speed.
Engine in the P-40E was supposed to hit FTH at 11,700ft with no RAM, Yet tests at 12,000ft or 13,000ft or 14,000ft. In fact for some reason in the US tests were done a bit above 15,000ft?
over 3,000ft seems a bit high to get best results from RAM?
The P-40 seemed to gain weight. Book figures say clean weight (with less that full fuel tanks) was supposed to be about 8,000lbs. Some early tests are about that (not going to argue about 40-50lbs one way or the other) but some tests say the plane was around 8400lbs clean.

We have a P-40D doing 354mph at 15,175ft?
We have a P-40E doing 342mph at 11,400ft making 1150hp.
Same plane is doing 340mph at 15,300ft making 990hp.

Was there something wrong with the P-40 air intake?
Was Allison lying about the power produced at 11,700ft?
We have power tables printed during the war for the -39 engine that show 1150hp at 15,000ft but post war books don't show that level of power at that altitude until you get to the -81 engines in the P-40M with the 9.60 supercharger gears.

Up at 20,000ft there is no contest, the Hurricane is going to win.

Shortround6 said:

P-40E numbers are all over the place. You can find about 30mph difference in top speed depending on which books/articles you read.

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Yup, it is strange and I have seen a few variations in Hurricane performance, too. During official performance trials of the Hurricane IIc by the A&AEE the maximum speed achieved by one particular example was only 306 mph, while a Hurricane IIB had recorded 330 mph. A Hurri I reached 324 mph, which is higher than the nominally accepted maximum speed for the Hurricane I. Kittyhawk Is demonstrated variations too, with one achieving 332 without drop tank and 322 with, but an entirely different Kittyhawk I reached 354 mph.

To keep this on track, I still think that either the P-40 or the Hurricane IIc could have fulfilled Australia's fighter needs. It's all very well and good proposing different designs for Australia to build, but as I mentioned earlier it depends on when the need arises. If it's after Pearl Harbor, Australia doesn't need to wait long as the first P-40s were handed to the RAAF in March 1942. Not worth putting an entirely new design into production of a type that Australian industry has no experience building. It's lumbered with a lesser performing type that serves little purpose in the long run.

Before PH the answer is easy, why not build the Hurricane under licence? Structurally it relates to the Wirraway a little, welded steel tube, but of course the Merlin production is the issue. Australia will just have to build its own...

Shortround6 said:

P-40E numbers are all over the place. You can find about 30mph difference in top speed depending on which books/articles you read.

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Maybe in books and articles, but primary sources are IMO pretty consistent. Before you start typing, please give me chance to explain what I mean.

If we are refering to reports and memos from wwiiaircraftperformance, we need to be very careful because not all tests are about measuring maximum speed. So yes, some report can for example show maximum speed during test 336.5 mph @ 14 900 ft (report FS-M-19-1580-A) however engine was running at 2940 RPM instead of maximum 3000 RPM.
Than we have for example Boscombe Down report, 10th part - maximum speed is 332 mph @ 14,400 ft, but there is a very important detail - manifold pressure is 41.5 inHg, not 42 inHg. When they did use really full power (42 inHg/ 3000 RPM), all of the sudden maximum speed is 344 mph @ 13 800 ft (same report, part 19).
Little details are crucial when we are talking about performance tests, it is very complicated, much more complicated than people think. And I do not mean you here, just in general.

Just my 2 cents.

nuuumannn said:

To keep this on track, I still think that either the P-40 or the Hurricane IIc could have fulfilled Australia's fighter needs. It's all very well and good proposing different designs for Australia to build, but as I mentioned earlier it depends on when the need arises. If it's after Pearl Harbor, Australia doesn't need to wait long as the first P-40s were handed to the RAAF in March 1942. Not worth putting an entirely new design into production of a type that Australian industry has no experience building. It's lumbered with a lesser performing type that serves little purpose in the long run.

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If we will really follow "What if Australia decide produce different fighter instead of Boomerang" than yes, it is after Pearl Harbor.

Historical timeline goes like this - date is January 1942 and Japanese are in war with Australia. RAAF do not have any fighters at all for defence, CAC is offering to build Boomerang. And I must agree with you, production of entirely new design instead of Boomerang is just not worth it. You need too much time for that.

nuuumannn said:

Before PH the answer is easy, why not build the Hurricane under licence? Structurally it relates to the Wirraway a little, welded steel tube, but of course the Merlin production is the issue. Australia will just have to build its own...

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Than this should be "What if RAAF before PH changes policy about fighters they need and demand single seater instead of two seater?". In that case Boomerang is most likely not even a thing.

Historical timeline - in 1939, Australia decide that RAAF is too weak and it should expand. Part of the expansion are two figher squadrons (at that time Australia have none) and RAAF insists that these fighters MUST be long range two seaters, ideally with two engines. Also, fighter squadrons have lowest priority in this expansion. In following weeks and months is RAAF looking for airplanes and although some single seat fighters are (kinda) offered to her, they are interested only in two seaters. They are seriously considering Seversky/Republic 2PA, however finally in May 1941 they order 54 Beaufighters from UK.

So in our "What-if" timeline at some point let's say around end of 1939 someone important in Australia is saying "Guys, we need single seat fighter planes, forget two seaters". Australia is therefore ordering fighters from overseas, something like P-36 from French order after summer 1940 or whatever. My point is - why bother with production of fighter in Australia if I can just import them at this point? Bear in mind that CAC is producing Wirraways at that time and they still need to build a lot of them (for Empire Air Training Scheme etc.). In this scenario Australia have some decent fighters (or frankly any fighters) at the start of the war with Japan, production of Boomerang can still be offered by CAC after PH but it is for sure considered even less important project than in real historical timeline. Also, in this "What-if" timeline RAAF do not get Beaufighters. Is it worth it? I don't know.

nuuumannn said:

Yup, it is strange and I have seen a few variations in Hurricane performance, too. During official performance trials of the Hurricane IIc by the A&AEE the maximum speed achieved by one particular example was only 306 mph, while a Hurricane IIB had recorded 330 mph. A Hurri I reached 324 mph, which is higher than the nominally accepted maximum speed for the Hurricane I. Kittyhawk Is demonstrated variations too, with one achieving 332 without drop tank and 322 with, but an entirely different Kittyhawk I reached 354 mph.

To keep this on track, I still think that either the P-40 or the Hurricane IIc could have fulfilled Australia's fighter needs. It's all very well and good proposing different designs for Australia to build, but as I mentioned earlier it depends on when the need arises. If it's after Pearl Harbor, Australia doesn't need to wait long as the first P-40s were handed to the RAAF in March 1942. Not worth putting an entirely new design into production of a type that Australian industry has no experience building. It's lumbered with a lesser performing type that serves little purpose in the long run.

Before PH the answer is easy, why not build the Hurricane under licence? Structurally it relates to the Wirraway a little, welded steel tube, but of course the Merlin production is the issue. Australia will just have to build its own...

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A lot depends on when certain decision were made.
And like a number of other aircraft, changes were made during the process.
The Beaufighter for example was supposed to be a minimum change to a lot of things from Beaufort. A lot was kept but not as much as they originally thought?
At certain points in time, which may have changed a just a few months later?, the R-1830 looked like the best bet for getting a 1100-1200hp engine into production in Australia the quickest. Once you start working on that what project happens 3-4 months later when somebody askes about building Merlins? Is somebody going to give you enough "stuff" to get Merlin production going sooner that the R-1830 production or will it just delay things by 3-4 months or do you have to rip out some of what you already have done and start over?

Australia was tiring to build all kinds of stuff and the aircraft programs did not exist in a vacuum. Australia had a rifle factory but no source for light (or heavy) machine guns.
They came up with the Charlton LMG

Not a great solution but beats the heck out of nothing.
They started work on the Sentinel tank in 1940

There may have been other programs that were all competing for factory space and machine tools and workers.
Australia, for a period of time, was trying to figure out what they could make on their own with either no imports or a minimum of imports.
Once the US had increased production and shown it could keep supplies moving and Japan was not moving as fast to expand as feared the need to keep everything Australian made decreased. The US and the Commonwealth (and Australia herself) were able to supply more machine tools and equipment to expand factories at time went on. But what Australia could do in 1944 is not what Austral could do in 1941/42.

Another reference I highly recommend if you are seriously interested in the development/capability of Australia's Defence capability in the lead up to WWII:

Shortround6 said:

A lot depends on when certain decision were made.
And like a number of other aircraft, changes were made during the process.
The Beaufighter for example was supposed to be a minimum change to a lot of things from Beaufort. A lot was kept but not as much as they originally thought?

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I don't really see exactly what this has to do with Australia choosing the Hurrricane or the P-40. Let's put it this way, if the point you are making is specifically about the Hurricane and its fabric covered wings and the fitting of a wooded propeller, then those changes can easily be remedied as they traditionally were over time. They didn't require redesign of the whole airframe - there was virtually nothing in common between the Beaufighter and the Beaufort. As for the Hurricane's wings, it was only the outer wing panels outboard of the undercarriage that had fabric covering, the wing centre-section was all metal from the outset and underwent no change to incorporate the metal outer wings. Since the basic structure beneath the early wings was all metal, the decision to change it to a metal skin was not a major change, the only structural change being in the gun bay access door layout. As for the props, as mentioned in another thread, squadron Hurricanes began receiving C/S props in late 1939, which also didn't require too much effort to have been done.

As mentioned, timing is the key. It depends entirely when this was done. Being a Commonwealth country, Australia, as well as New Zealand and Canada had pressure on them to "Buy British" and by and large it played out that way before the war. Obviously during the war that changed, but not without a few words from Britain accusing the Commonwealth of abandoning it.

The reality was that when Lawrie Wackett returned from his tour and decided that the Commonwealth Aircraft Corporation was going to build an American designed trainer, which became the Wirraway, there was not universal approval within the more Britophile facets of the government. For Australia to put a non-British fighter into production before the war is stretching things a little. The Wirraway had to happen before the industry had the confidence to take on something more advanced, but if it were a fighter that the CAC was going to build, the Hurricane stands a better chance than most other types.

That's before the war, of course...

The P-40 was Australia's most numerous fighter of WW2.