P-39 or P-40 for rest of war?

[davebender]

The shorter range of the P-39 would be a serious issue in the Pacific (i.e. where Australia is located). It would not be as much of a problem in the European war.

 

[Colin1]

The shorter range of the P-39 would be a serious issue in the Pacific (i.e. where Australia is located). It would not be as much of a problem in the European war.

Both types would have range issues in the Pacific
one of the constraints imposed by the OP was mainland defence only

In the ETO you'd be trading one set of problems for another, the single-stage Allisons would not be able to compete with the Luftwaffe

 

[Thorlifter]

The P-39 could climb all over the Bf109E
If the Aussies did go ahead and do some work on the engine, who's to say it couldn't have climbed all over the Bf109F?

True Colin, but the scenario is for Australia. Their primary advisary would have been the Zeros, G4M's, and Oscars, not Luftwaffe fighters.

As I noted, I gave a big advantage to the P-39 over the P-40 in regards to rate of climb.

 

[Colin1]

True Colin, but the scenario is for Australia. Their primary adversary would have been the Zeros, G4Ms, and Oscars, not Luftwaffe fighters.

As I noted, I gave a big advantage to the P-39 over the P-40 in regards to rate of climb.

My point
not clearly made, was that the P-39 had it over arguably the best fighter in Europe at the time for manoeuvrability and the best fighter in the Pacific for speed.

 

[vanir]

Australia did evaluate both, the P-39D's were assigned to "intercept" duties near Canberra (82 Sqn) whilst P-40 training squadrons were sent north and west. I believe the main factors in settling on the P-40 was ease of pilot training and conversion to the type and it was assumed this was the most likely model to experience continued development in the 'States. In fact from what I've read if it wasn't for the Russians the P-39 would've passed out of production before the N series.

Also gettings parts for the Merlin was difficult in Australia, it was very far away from Britain and primary strategic materiel for them and in the States Packard production fell short as it was. We used something like a dozen total Merlin engine P-40's through the whole war and always relied on the Allison. Parts were available without having to set up local manufacturing. The main reason we took the Beaufighter was because we started making Hercs, I believing taking on licensed Merlins would've been harder.

I do believe the F-series Allison should've been fitted with a two-speed Merlin XX style supercharger from the start, the reason it wasn't was bureacratic. I mean aside from the whole high altitude, turbosupercharged thing, just making the F-series more like the Merlin XX for supercharger performance, after all the Packard was a Merlin XX.

In any case I'm with the RAAF on this. The P-40 was by far the better choice. My personal preference, as a pilot? The P-39.

 

[michaelmaltby]

We are talking about defending Australian airspace - first and foremost - right??. The BofB with France being more than a few klics over the channel.

But the Japanese are NOT the LW. Their planes aren't up to German standards - overall - and their missions are long range.
To respond to these conditions the RAAF pilots faced with the realities of the sitution and the P-39 would have to adapt.

Both the P-39 and P-40 are less than ideal - so was the Brewster Buffalo - and we know what the Finns did with that.

MM

 

[Shortround6]

Also gettings parts for the Merlin was difficult in Australia, it was very far away from Britain and primary strategic materiel for them and in the States Packard production fell short as it was. We used something like a dozen total Merlin engine P-40's through the whole war and always relied on the Allison. Parts were available without having to set up local manufacturing. The main reason we took the Beaufighter was because we started making Hercs, I believing taking on licensed Merlins would've been harder.

Have you got a reference for the Australian Herc?

I believe Australia did make licensed Merlins, but perhaps not until the very end of the war or just after?

 

[Glider]

My point
not clearly made, was that the P-39 had it over arguably the best fighter in Europe at the time for manoeuvrability and the best fighter in the Pacific for speed.

I am sorry but that doesn't fit in with my understanding. If the P39 was that good the RAF would have been yelling for more instead of getting rid of them as fast as possible.

There was a tactical comparison held between the Me109, P39 and Spit V in July 1941 and the report was presented in September 1941.
Briefly below 20,000ft the P39 was superior in the level against the Bf 109E(speed and manoevrability) but above that the P39 lost its advantage of speed. The Bf109E could always climb faster than the P39.
Note - It should be remembered that in mid late 1941 the P39 would be facing the 109F which was a significant improvement on the 109E

Against the Spit VB,
Speed - at 13,000 ft the P39 was 18mph faster, at 15,000ft they were matched, at 20,000 ft the Spit was 35mph faster, at 24,000 ft the Spit was 55mph faster.
Climb - The Spitfire always outclimbed the P39
Turn - The Spitfire outurned the the P39 but it was close.
Take Off - The P39 had a ground run of 2,250ft the Spitfire 1,590ft.

Also the aircraft wasn't ready for combat. If the USAAF considered them to be ready it says a lot for the lack of testing that had been done.
The list of problems included
a) The oxygen couldn't be turned on from the cockpit!!
b) The Gun Sight had to be changed so the pilot could see clearly out of the front of the aircraft
c) Ammunition Tanks for the 0.30 guns had to be changed as they distorted
d) The IFF had to be moved as it blocked the view to the rear.
e) Incorrect wiring had to be replaced
f) When the nose guns fired the carbon Monoxide levels in the cockpit could reach lethal levels.
g) Maintenance of guns was very difficult, all guns were inaccessible in particular
..i Time taken to remove the recoil mechanism of the 0.50
..ii problem with loading and unloading the 0.30
..iii allignment of the ammunition tanks
h) on firing tests the 0.30 jammed 36 pct of the time, the 0.50 22 pct of the time the 20mm worked perfectly.
I) Compass problems
j) Guns couldn't be fired at night as it destroyed the pilots night vision
k) Reserve fuel feed failure

So in summary the P39 was far from being the best fighter in Europe. The Spit V was better apart from speed at low altitude and the 109F was at least as good as the Spit V. Even the 109E could take care of itself above 20,000ft and
By the time the P39 was available in numbers the Germans have the Fw190 and 109G entering service and the RAF the Spit IX, any of which was way ahead of the P39.

 

[vanir]

Have you got a reference for the Australian Herc?

After checking my memory with local records I stand corrected, the Beaufighter was license produced locally but the engines imported, I was certain I'd read somewhere the reason we produced the Beaufighter was because we were making Bristol engines (at Fisherman's Bend iirc) for other aircraft and it was readily adapted to license produce Hercs.
Not so after checking our local aviation museum sites, who clearly state they were all imported.

We did use Bulldogs in the RAAF/maybe we did make some other Bristol engine so perhaps that source was stating an assumption as fact. I should've checked.

 

[Shortround6]

We did use Bulldogs in the RAAF/maybe we did make some other Bristol engine so perhaps that source was stating an assumption as fact. I should've checked.

I have read that even Bristol was using main bearings imported from Sweden for the Hercules (both by plane and by converted MGBs) as they couldn't get bearings of the quality they wanted from British sources. Not to cast aspersions on the Australians but it seemed doubtful that they could have solved the bearing supply problem (or the sleeve valve problem) on their own.

As far as the sleeve valves go there is a story about how six Sidestrand centerless grinders were diverted from delivery to a P&W plant in Kansas, put aboard the Queen Mary and rushed to England for Napair's use in making sleeves for the Sabre engine during the early crisis in it's manufacture. P&W was not happy

There is more to making engines than having a set of plans.

 

[vanir]

Certainly so, from local metallurgy to everything else. Too true.

 

[Colin1]

I am sorry but that doesn't fit in with my understanding...

Glider
there's nothing wrong with your understanding, you are quite right on all points
I didn't, however, claim that the P-39 was the best fighter in Europe, I stated that it was as manoeuverable as the best fighter in Europe. Note that I have not magicked the P-39 into two-stage supercharger land either, this is at the best altitude for the P-39, not the Bf109E.

 

[davebender]

Yipes! We had problems with P-40s operating in the Philippines and the P-38 problems are well known. Makes me wonder about the quality of U.S. Army Air Corps leadership during WWII.

 

[Markus]

On the PI it was logistics. Primitive bases, loooong supply line, brand new fighters(P-40B/E), green pilots, few spare parts.

 

[Glider]

Glider
there's nothing wrong with your understanding, you are quite right on all points
I didn't, however, claim that the P-39 was the best fighter in Europe, I stated that it was as manoeuverable as the best fighter in Europe. Note that I have not magicked the P-39 into two-stage supercharger land either, this is at the best altitude for the P-39, not the Bf109E.

I understand but we wil have to agree to disagree on choices. You take the P39 and I will take the 109F.

 

[davebender]

That's directly connected to leadership as the majority of American military shipping was in the Pacific during the fall of 1941. Somebody established the wrong transportation priorities.

HyperWar: Strategic Planning for Coalition Warfare, 1941-42 [Appendix G]
Nov 30, 1941
529,164 DWT in the Pacific vs 249,350 DWT in the Atlantic.

 

[Markus]

That's directly connected to leadership as the majority of American military shipping was in the Pacific during the fall of 1941. Somebody established the wrong transportation priorities.

HyperWar: Strategic Planning for Coalition Warfare, 1941-42 [Appendix G]
Nov 30, 1941
529,164 DWT in the Pacific vs 249,350 DWT in the Atlantic.

That reflects the view of the Japanese not attacking before mid-42. Besides, it was not so much how much but what was shipped that was wrong. "Swedish" P-35A instead of the proven P-36, B-17 instead of AA-guns and radar sets...

Back to the topic:

I took a look at "America´s 100,000" and both the P-39D and the P-40E seem useless as interceptors. The Japanese routinely operated at 25,000ft. It takes a P-39D 15 minutes to reach that altitude and ideally a fighter should start the attack from a few thousand feet above the target. Climb times for Warhawks are even worse, even for the F-version. So both planes would be used as medium altitude fighters and fighter bombers. The P-40 is the less complicated and more readily available of the two.

 

[michaelmaltby]

"... The Japanese routinely operated at 25,000ft"

True - but attacks often were mixed - bombers and dive bombers - the fighters stayed with the DB's (strafing and civilian terrorism) which brings them down to the prime altitude of the P-39's - 10,000 - 11,000 feet - vertical plane)

I posted earlier that the RAAF would have to devise "tactics" to suit the P-39's strengths: it is fast at low altitude, climbs well, has limited range but carries a 500 lb external payload.

"Tactics" : (fictional, of course )

1. -- Be air born quickly from widely dispersed strips. Reach 10,000 and assume climb-launch-attack attitude

2. -- Launch unguided, fragmentation rockets with timed fuses (for 25,000') at the bomber formations from about 10,000 feet. (The rockets are from an Austrian-developed "dispenser system" holding 8 missiles mounted on the center-line hard-point of the P-39.). The dispenser is very basic and disposable

3 Stay below 11,000' to take on the dive bombers, fighters and "wounded" bombers as they descend. (remember the Japanese bombers don't have SS gas tanks or armor) with the 37mm and the 2 50's in the nose.

Australia had the resources and industry to develop such a rocket dispenser system if they had been forced to fight with the P-39, IMHO.

MM

 

[Glider]

I notice that a number of posts have said that the P39 was good in the climb. If the P39D took 15 mins to get to 25,000 ft and its my belief that the A6M2 made 20,000 in around 8 mins, then to put it briefly it sucked.

Is my understanding correct ie that the P39 was very poor in the climb or have I got it very wrong?

 

[davebender]

Both Hawaii and the Philippines had operational radar on December 7, 1941. In both cases they detected the Japanese air raids at a considerable distance.

Everyone knows about the Pearl Harbor radar SNAFU. Here is a good description of the Philippine radar and their equally screwed up communications system.
From Shanghai to Corregidor: Marines in the Defense of the Philippines (Defenses of Manila Bay)