WW2 Etc The USAAF

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Hamilcar 4/18/2010 12:17:36 AM

These threads are fun. Here's my changes for the USAF:

Develop a decent cannon. Probably go for a 20mm version of the M2.

It gets thin after this. Where did they really screw up? I am a radial "fanboy" and dislike the liquid cooled engines intensely but if I say ditch the V then there may be no P-38.

I can't ditch the 17 and only build 24's because the 17 was better in the ETO.

I would ditch the P-39.

Any suggestions?

1. They had a decent cannon in the HS-404. Just don't screw it up. Let BENDIX make it, and keep Oldsmobile away from it.

2. Corncob the R-1830 with a three row 21 cylinder version 1800 HP version. Start on that in 1935 Have it ready by 1938 for the XP-49. Use that for some of the weird pusher prop US fighter designs as well as the P-75.

3. Why ditch the P-39?

4. Work on and get the axial flow turbo-jet into production. There was one, (the L-133), there was no reason to have to start in 1943 ro design or duplicate British jet engines. We could have our own 10,000 kilonewton engine ready by then.

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earlm 4/18/2010 12:39:53 AM

I think the P-40 was a superior aircraft although I know you don't agree.

BTW check out AG Williams' site for your question about building a bigger Browning. Evidently some components in the Browning are highly stressed and the Japanese had to lower the power of the cartridge in their version.

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Hamilcar 4/18/2010 2:50:08 AM

I think the P-40 was a superior aircraft although I know you don't agree.

I don't agree with that.

HO-155...

The 30 mm Ho-155 Browning
Copyright © 1999 by T. E. Bradstreet...
All Rights Reserved



Had WW II continued into 1946, the IJA 30 mm Ho-155 Browning machine cannon (often mis-designated Ho-105) would have become first line anti-bomber armament in IJA fighters and interceptors. It was starting to be used in early 1945, if only on a trial basis, and gun production was well under way. The four images attached, though of varying quality, show the evolution of this gun. They are approximately to scale, and are aligned to one another on the belt feedway.

The ancestry of the Ho-155 begins in 1942 with the 25 mm Ho-51 Browning (top image). This gun was intended to replace the 20 mm Ho-5, using the same airframe space for mounting if possible. The Ho-51 fired a 25 x 115 mm cartridge, very seldom seen since little development was done in 25 mm. Like its ancestors and descendants, the Ho-51 used typical Browning disintegrating link belt feed, and was developed by Chuo Kogyo K.K. in cooperation with the Third Army Aerotechnical Laboratory at Tachikawa. This gun, possibly unique, is probably now the NASM or USAF Museum. The caliber was soon expanded to 30 mm, and development of the Ho-155 around the 30 x 115 cartridge began in 1943. While a 25 mm projectile holds about 1.5 times the explosive of a 20 mm projectile of the same length, a 30 mm projectile holds 2.25 times the 20 mm, justifying the change.

Of course, the heavier 30 mm projectile required more power to achieve a similar trajectory, and the Ho-155 prototype (second image from top) reflects this. While it used the Ho-51 receiver and internals, a long and complex forward extension (bracketed in image) was added to support a heavy barrel for the larger-bore more powerful cartridge. The extra power also required a muzzle brake (indicated by arrow). This is somewhat unusual in a recoil operated gun and means the cartridge developed more power than necessary to run the gun. The prototype muzzle brake copied the "ice-cream cone" muzzle brake of the IJA 37 mm Ho-204 (Type 4) Browning. Apparently, the Ho-51 receiver and internals were inadequate to the 30 x 115 cartridge. The heavy barrel, with the receiver extension supporting it, also added a great deal of weight, undesirable in a gun to replace the Ho-5. This specimen should also be in the US.

From this prototype, the Ho-155-I (second from bottom) was developed 1943-44. The gun shown is now at the USAF Museum at Wright-Paterson AFB, Ohio. It is a Ho-155-I otsu (right-hand feed), serial number 108, manufactured by Nagoya Army Arsenal in February 1945. This gun, though adequate to its cartridge, is significantly larger than the Ho-5 and Ho-51. As yet, no photographic evidence of its installation in any aircraft has been seen.

Beginning in 1944, the Ho-155-II (bottom image) was developed by down sizing the Ho-155-I to fit fighter wing bays intended for the Ho-5. The result approximated the compactness of the Ho-51, but, as might be expected at this point in the war, reliability problems resulted. Nevertheless, production commenced. This specimen, also now at the USAF Museum, is marked as a Ho-155-II ko (left-hand feed), serial number 433, made at Nagoya in March 1945 . Another specimen, presently at

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Hamilcar US technology that needs pre-WW II upgrades. 4/18/2010 9:52:02 PM

1. Gun-sights....

I said somewhere that the US had led the world in the first reflex gun-sights in the early 1930s? Later the British and Germans designed gyro-corrected lead gun-sights and the Americans either adapted British, or designed their own.

Well, that should have led to a primitive HUD; like the the turbo-charger should have led to the jet engine ( as it did finally).

2. Propellers 1....

Propellers 2....

Do the wind-tunnel work to optimize the props to the planes. Climb to altitude was an American aircraft problem. Its easier to fix this in the propeller, than it is in the engine.

3. Supercharged....

If you are going to design an engine, then start thinking of the whole engine as a pod that goes into the aircraft. Too many American aircraft look like plumber's nightmares with air duct piping that would make Rube Goldberg go out and shoot himself. Each aircraft designer designed his own air flow solution. FIX THIS! The pod should mount to the aircraft with the propeller assembly, the supercharger, turbo-charger, the engine, the radiator, the inter-cooler, and stack exhaust all together as a common power unit.

4. Glide bombs. ...

The basis of daylight strategic bombing had to be precision strike. That meant command guided weapons: since there was no way to correct for wind drift up, down, left, or right once the bomb left the aircraft. Solve the problem in the bomb. This was so obvious, I don?t understand to this day why no-one really tried before WW II to design such a munition. There were possibilities, (see link.), but they were not followed up. Of special interest in this regard was the BAT.

More later.

...

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sentinel28a 4/20/2010 1:58:05 PM

There was actually nothing wrong with the basic design of the P-39. Wright-Pat effed up the design by trying to turn it into an attack aircraft and adding stuff that really didn't need to be there. It ruined a very solid design by Bell for a nifty little fighter.

No argument that Oldsmobile didn't do too well with the 37mm cannon. PT boats had some luck with it, but they could clear a jam instantly when (not if) one occured. Then again, the USAAF distrusted cannon from the beginning and didn't use them during the war, preferring the .50 since you could load more ammo, fire faster, and have greater range. However, the killing power of cannon was needed (which was why the USN started edging towards them by 1945), and guys who converted from late-model Spitfires to P-47s and P-51s lamented that they really missed having those 20mm.

One suggestion I would have would be, if possible, to put the B-29 in service even sooner. The Germans had nothing that could touch it, which was why they crash-programmed the Me-163.

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Hamilcar 4/20/2010 6:07:55 PM

There was this wrong with the P-39.

1. No endurance in the air.

2. Inadequate throw weight per second in the planned armament.

3. Engine cooling problem unresolved.

4. No room to fix any of this in the airframe with 1937 US tech.

5. The problems could be fixed only with the following achievements

a. drop tanks plumbed for the winds.

b. a 20 mm cannon in the nose with 20 seconds of ammo and four 12.7 mm machine guns with 20 seconds of ammo in the wings.

c. 1100 kw hyper-engine aspirated for 7000 meters.

d. A slide bubble canopy as opposed to that botched car hard top job.

Blame Oldsmobile for that too. They screwed up the American Hispano.

One suggestion I would have would be, if possible, to put the B-29 in service even sooner. The Germans had nothing that could touch it, which was why they crash-programmed the Me-163.

No.

XB-28.

Need a fast raider.

Fix the B-32 Dominator with a Pratt R-2800 engine early, and send THAT to Germany.

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sentinel28a 4/22/2010 4:31:14 PM

The B-32 wasn't as clean as the B-29. Except for its tendency to lose engines, the B-29 was a solid design and was ahead of the B-32 in development. The only reason the B-32 went into (limited) service was because Arnold wasn't willing to bet the whole farm on the B-29.

The canopy on the P-39 was due to the engine placement. Not sure about the cooling problem. Bell designed it to be a point-defense interceptor, like the Spitfire.

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Hamilcar 4/22/2010 10:32:27 PM

1. The B-32 was a more stable bomber.

2. The B-32 was FASTER at efficient cruise.

3. The B-32 used fewer materials and fewer men and cost much less to make.

Hap Arnold could afford two bombers. Cancel the Liberator and rush this into production. The reason he didn't push the Dominator was that it was shorter-ranged than the Superfort and would have trouble making the run from Tinian to Tokyo. it was that simple.

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VelocityVector 4/22/2010 10:57:09 PM

My historical knowledge is limited. I am curious whether the Allied countries engaged in any research during WWII with focus on contra-rotating props or >6 blade props. Contributions appreciated even if just hyperlinks.

v^2

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gf0012-aust 4/22/2010 11:08:34 PM

link

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