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Have gotFor 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.
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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.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
Assuming you could make a roughly 6,000 - 6,500 lb OzHawk, you would have the following traits:
A lot depends on how you figure climb. Initial climb from sea level for the 1st minute?*Faster climbing than a Kittyhawk or (probably) a Wildcat
Now it's get dicey because the P-36/Hawk 75 was only supposed to go into combat with 105US gallon on board.Better range / endurance than a Spitfire or P-39
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.*Simpler maintenance than a Kittyhawk, Spitfire, or P-39 (probably, due to air cooled engine)
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.*Less vulnerable engine than a Kittyhawk, P-39 or Spitfire
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.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.
Why not use the R-1830 with the two stage supercharger that the Wildcats had?
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.
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
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.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).
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.
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.
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.
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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,
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.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.
Be very careful with the weights of both planes.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
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.
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.
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.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.
@ 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).
What do you think was the earliest they could do it? I don't want to bend things too far.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 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.
What do you think was the earliest they could do it? I don't want to bend things too far.
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.
There is an explanation of the various FAA Martlets and their distinguishing features here.
The Mark I and III (both the 10 relabelled Mk.II and 30 ex-Greek Mk.III) had fixed wings.
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.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.
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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.
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?
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.
Wikipedia is usually wrong mate.
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: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.
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...
Thank you. I've found many of your various posts around this forum also quite interesting as well.Your points are interesting reading though, Bill.