Improve That Design: How Aircraft Could Have Been Made Better

[jmcalli2]

"Big Army", who held the purse strings for USAAF, still tended to think of pursuit aviation as a battlefield tool, not a defensive or strategic asset.

Which, interestingly, was how the USSR used the P-39.
And they had great success with it.

 

[XBe02Drvr]

Which, interestingly, was how the USSR used the P-39.
And they had great success with it.

But as a local air superiority weapon, not a tank buster or a troop attacker.

 

[P-39 Expert]

Once the AAF had decided the P-39 was for ground attack, they put a LOT of armor into it. Some models had almost four times the armor of a Spitfire:

The WWII Fighter Gun Debate: Fighter Armour

The other issue with the AAF during the first two years of the war was their babying of the V-1710. While evaluating the Mustang I the RAF found they could use it at much higher boost levels than the manuals allowed; in fact, the throttles were locked at 44" Hg. The RAF found they could operate the Allisons at up to 72" Hg for 20 minutes without harm to the engine:

E-GEH-16. near the bottom of the page.

Gotta wonder what the P-39 would have done with the extra boost.

Extra boost would only be available up to the critical altitude of around 14000' with ram.

Interesting how the Brits required 120kg of armor on the P-400 (P-39) but only 33kg on their Spitfire.

 

[jmcalli2]

Once Lend-Lease was approved as official policy, planes passed through US ownership enroute to allies. Prior to that, they were direct purchase export products and belonged to their purchasers. This happened in the middle of production of several types: Boston, Harvard, Maryland, Catalina, Hawk 75, Tomahawk, Airacobra, to name a few.

The production numbers in total match the entire production run for each model. It's down at the bottom of the column for each fighter.
For example, the 13,738 P-40s matches total production cited in Angelucci and Matricardi 1978, p. 48

U.S.A.A.F. Fighter Monthly Acceptances (1940-1946)

 

[jmcalli2]

But as a local air superiority weapon, not a tank buster or a troop attacker.

The P-38 was never a tank buster. The 37mm M4 was designed as a bomber killer. While there was an AP shell produced, that shell was never provided to the USSR. They only got the HE shells.
You don't get to be the American made fighter that shoots down the most enemy planes in WWII by firing at tanks.

 

[XBe02Drvr]

The production numbers in total match the entire production run for each model.

Betcha those totals were compiled "for the record" after Lend-Lease became official.

 

[jmcalli2]

Extra boost would only be available up to the critical altitude of around 14000' with ram.

Interesting how the Brits required 120kg of armor on the P-400 (P-39) but only 33kg on their Spitfire.

Reading those reports can give a lot of "peripheral" information that makes you go, "Hmm!"

Like, why did the AAF stop testing maximum speed on the P-43 at 15,000 feet when it was supposed to operate from 20,000-25,000 feet? Hmm.

 

[XBe02Drvr]

The P-38 was never a tank buster. The 37mm M4 was designed as a bomber killer. While there was an AP shell produced, that shell was never provided to the USSR. They only got the HE shells.
You don't get to be the American made fighter that shoots down the most enemy planes in WWII by firing at tanks.

We're on the same page here. My comment was a reflexive response to the common myth that the P39 was intended for attack work. I see now that was not your intended implication.

 

[Milosh]

The production numbers in total match the entire production run for each model. It's down at the bottom of the column for each fighter.
For example, the 13,738 P-40s matches total production cited in Angelucci and Matricardi 1978, p. 48

U.S.A.A.F. Fighter Monthly Acceptances (1940-1946)

Looks like a copy from, army_air_forces_statistical_digest_ww2_1945.pdf (91stbombgroup.com)

 

[XBe02Drvr]

Like, why did the AAF stop testing maximum speed on the P-43 at 15,000 feet when it was supposed to operate from 20,000-25,000 feet? Hmm

Ref post #692. "Who cares about the stratosphere? It's troops on the ground need protection!"

 

[XBe02Drvr]

Extra boost would only be available up to the critical altitude of around 14000' with ram.

And that density altitude would be at a much lower MSL physical altitude in a tropical climate. Taking off at sea level on a summer's day in Key West, we could be starting off with a density altitude of 1,000-1500 feet, and that's only subtropical. A Cessna 150 with two lanky guys aboard and the magneto timing adjusted for 100LL has a climb performance slightly shy of a lead sled and feels like a solar heated phone booth full of octopi.
With the standard cruise prop, that little 200 cu in, 100 HP, 80 octane engine running on 100LL can only muster 87 HP at Vy. Thank God for thermals!

 

[jmcalli2]

We're on the same page here. My comment was a reflexive response to the common myth that the P39 was intended for attack work. I see now that was not your intended implication.

I understood, just reinforcing you.

 

[jmcalli2]

Looks like a copy from, army_air_forces_statistical_digest_ww2_1945.pdf (91stbombgroup.com)

Could be. At the top of the page are links to the data in a spread sheet format which may be useful. I didn't check to see if the links were still active though.

 

[P-39 Expert]

And that density altitude would be at a much lower MSL physical altitude in a tropical climate. Taking off at sea level on a summer's day in Key West, we could be starting off with a density altitude of 1,000-1500 feet, and that's only subtropical. A Cessna 150 with two lanky guys aboard and the magneto timing adjusted for 100LL has a climb performance slightly shy of a lead sled and feels like a solar heated phone booth full of octopi.

Yes and your opponent would be flying in the same atmosphere.

 

[swampyankee]

Extra boost would only be available up to the critical altitude of around 14000' with ram.

Interesting how the Brits required 120kg of armor on the P-400 (P-39) but only 33kg on their Spitfire.

How did one need to arrange the armor to get comparable protection?

 

[XBe02Drvr]

Yes and your opponent would be flying in the same atmosphere.

Yes, but with a significant supercharger advantage and a super lightweight and high lift airframe. Superior power giving superior thrust/weight, and superior L/D at altitude.

 

[jmcalli2]

How did one need to arrange the armor to get comparable protection?

 

[wuzak]

Extra boost would only be available up to the critical altitude of around 14000' with ram.

Not only that, the full extra boost of 72" MAP was only available at sea level, reducing with altitude until the standard boost was reached at critical altitude.

 

[GrauGeist]

How did one need to arrange the armor to get comparable protection?

Easy, really. To improve performance, simply remove the front, rear and pilot plates as well as the safety glass. Push the aircraft into the ocean and get a P-38...

 

[Stig1207]

True on the early warning system of observers, sometimes called coast watchers. They were usually people who lived in the area, farmers, etc. Hazardous as they were hunted by the Japanese.

Australian radar was just too far away to do much good. Radar was installed at Milne Bay in August and at Port Moresby in September, but from April until August/September they were blind for incoming raids. And those raids were coming from Lae less then 200 miles away. Either fly patrols with the two squadrons available or wait on the ground. Tough duty.

I've always maintained that the P-39 would have been much more effective much higher up had it weighed less, and the weight reduction could have been accomplished at forward bases.

Huh? It was the coast watchers that provided early warning of incoming Japanese raids, so the P-39's were up at altitude waiting for the raiders. It was the Japanese that had no early warning system and were blind to incoming raids over New Guinea in 1942.

You don't get to be the American made fighter that shoots down the most enemy planes in WWII by firing at tanks.

It might be the American made fighter that claims the most enemy planes shot down in WWII, but it is certainly not the one that actually shot down the most enemy planes.