P-40 top fighter?

[P-39 Expert]

Are you sure they didn't blow instead? After all, we are talking turbo/superchargers which are commonly nicknamed "blowers"...

...

Why are you looking at me like that?

OooooKay, I'll just grab my coat and be leaving now...

It depended on which side of the impeller you were looking at. If you were looking at the carburetor side then it sucked. If you were looking at the intake manifold side then it blew.

So it sucked and blew simultaneously.

I'll get my coat too.

 

[jetcal1]

Grumman and Seversky. The former submitted a biplane, which was redesigned as the F4F-2 and the latter a variant or derivative of the P-35

Sorry, I wasn't clear. I was thinking of the dive bomber competition which spawned the SB2C

 

[P-39 Expert]

Problem of P-40 was in front of the firewall, not behind.

An argument can be made that the Problem was behind the firewall. The engine was a given, it produced 1150hp and that was it until it could be further improved.

There is no way in the world that an 8400# airplane can be a successful fighter with an 1150hpTO engine. That's 7.3#/HP. Contemporary Spitfire Vs, 109s and 190s were in the 4.7 to 5.3 range.

Just too heavy to be competitive without a two stage supercharger or a lot more HP and neither were available until much later.

The P-40's predecessor was the P-36 that weighed 5700# loaded. I'm sure it needed leakproof tanks and armor plate/glass, 4x.50cal MGs would weigh more than the one .50cal and one .30cal gun and it would need a Prestone cooling system, but that's still a long way from 8400#. My ex-wife didn't gain that much weight.

 

[tomo pauk]

An argument can be made that the Problem was behind the firewall. The engine was a given, it produced 1150hp and that was it until it could be further improved.
There is no way in the world that an 8400# airplane can be a successful fighter with an 1150hpTO engine. That's 7.3#/HP. Contemporary Spitfire Vs, 109s and 190s were in the 4.7 to 5.3 range.
Just too heavy to be competitive without a two stage supercharger or a lot more HP and neither were available until much later.

Aircraft gaining weight happened everywhere, not just with P-40. The increase of weight due to the incrase of firepower, protection and strengthening of aircrame was a result of realities of air combat. If the engine power was not improving by same of better rate, people ended up with underperforming aircraft. Check out the Zero 52c - addition of protection and firepower turned the passable fighter into a turkey because the engine power remained the same. Fw 190A - from the fighter with 20+ mph advantage in it's 1st year it turned into underperformer vs. Allied best of late 1943 on. The big gain in power under 2 km was of no help above 6 km, and 190 gained almost 2000 lbs between A2 and A8, clean, along with more drag.
P-40 can solve it's problems with either with far better engines, or with deletion of protection, reduction of armament, and reduction of fuell tankage. The later 3 options are out - nobody needs an aircraft that becames a torch with a dead pilot after receiving a dozen of bullets, with sub-par firepower, and without range required. The option 1 - far better engine - can solve problems much better, yet the P-40 never got that.
We can see that by mid 1941- late 42, the best performing fighters were powered by engines capable for 1150 HP above 18000 and better. The V-1710 in P-40 was making 900 HP there (V-1650-1 was better, 1150 HP). From late 1942 to late 1943, the best fighters have had engine powers of between 1250-1400 HP (smaller ones) and 1850-2000 HP (R-2800 powered fighters) above 18500 ft - the P-40 have had 1000?

The P-40's predecessor was the P-36 that weighed 5700# loaded. I'm sure it needed leakproof tanks and armor plate/glass, 4x.50cal MGs would weigh more than the one .50cal and one .30cal gun and it would need a Prestone cooling system, but that's still a long way from 8400#. My ex-wife didn't gain that much weight.

Switch from a relatively simple radial of a modest displacement to a decent liquid cooled V12 will ad 800-1000 lbs easily. It will also improve streamlining if design shop is half decent, and P-40 was and overall improvement over P-36.
6 HMGs are heavy (470-480 lbs as in P-40s), with heavy ammo. Protected fuel tanks - 400 lbs? 93 lbs of armor. How much for beefing up the structure?
IIRC there was a say that any pound worth of improvement required a pound to be added to the existing structure.
At the end of the day, the gross weight of the clean P-40E and similar was 1000-1200 lbs greater than of the P-40 (no letter - roughly it was P-36 with V-1710), and 500-700 lbs greater than of the P-40B. P-40F was even heavier.

 

[swampyankee]

The P-40 actually had pretty decent aerodynamics; the variants in service were competitive against both the FW190 and Bf109 at low to moderate altitudes, despite being heavier than either because of them. I don't think the P-40 was ever a world-beater, but it wasn't junk.

Obviously, the aerodynamics of the P-51 were better than those of the P-40 (they were likely the best of any single-engine propeller fighter to see service.).

 

[Shortround6]

The Curtiss Hawk 75/P-36 started porking up fairly early in it's career. One of the initial drawings gives a total weight of 4775lbs (includes 164.5lbs of armament and 24.5lbs of pyrotechnics/landing flares? )
This is the initial version with the Wright 14 cylinder R-1670 Twin Whirlwind engine, this engine performed so well (sarcasm) the the Curtiss aircraft division of Curtiss-Wright resorted to installing a P & W R-1535 14 cylinder engine. Weights with the Wright R-1670 engine are given as 3,760lbs empty, useful load of 1,083 lbs (make note of this) and gross weight of 4,843lbs. Max speed 281mph at 10,000ft and a range of 547 miles (speed and altitude not given). This was in the late spring of 1935.
By April/May of 1936 the Hawk 75 was on it's 3rd engine (the P&W R-1535 failed to give the desired performance.) A Wright R-1820-39 9 Cylinder Cyclone, but this engine too gave trouble and both the Hawk 75 and the Seversky aircraft missed the performance guarantees (the Army wanted 300mph for one thing) . Weights with the Cyclone engine were 4,049lbs empty, 1025lbs useful load and 5,074lb loaded, Max speed was 185mph at 10,000ft. This airframe would later become the XP-37.

The army does order 3 Y1P-36s as they are not too happy with the P-35. The Army specifies the use of the P & W R-1830 that was used in the Seversky prototype in the April 1936 fighter trials as the Army thought it was the best performing engine.
The empty weight went to 4,389lbs, useful load to 1071lbs, normal gross weight to 5460lbs and max gross weight to 5960lbs. normal fuel was 100 gallons and max fuel was 150 gallons.
Max speed was 294.5mph at 10,000ft using 900hp and cruise was 256mph using 600hp. range using 150 gallons of fuel was 752 miles.
there were a host of proposals and unbuilt variants to go with the confusing list of planes actually built. however the weight s given for the fixed landing gear Hawk 75H (with a Wright Cyclone 9) are instructive.
wing .........................780lbs
tail..............................107lbs
landing gear......... 342lbs
Fuselage..................467lb

airframe total ........1696lb

Powerplant .............1893lbs
Fixed equip..............386lb

empty weight .........3,975

useful load................1330lb
comprising
pilot..............................200lbs
120 gal fuel................720lb
oil.....................................68lbs
armament...................174lb
radio..............................100lbs
oxygen system.............15lbs
signal pistol/flares.........8lbs
landing flares.................50lbs

the design provided for additional fuel, oil, wing guns and bombs with a max gross weight of 6,418lbs. however at a 53-5lb gross weight the plane had an ultimate load factor of 12.1 and max dive speed of 385mph (BTW the Y1P-36s were 'red lined" at 390mph IAS)
Curtiss finally gets the production order for 210 P-36s and the early planes suffer from the wing areas around the landing gear are buckling and fuselage skins were wrinkling, the early P & W engines needed a bit of sorting out too. The problems are resolved. The P-36As weighed 4,567lb with a useful load of 1083lbs (remember the HAwk 75 prototype?) and a normal gross weight of 5,650lbs (max 6010lbs). max speed is 300mph at 10,000ft with the -13 engine and 92 octane fuel and 313mph at 8,500ft with the-17 engine and 100 octane fuel. Arment is one .50 cal with 200rpg and one .30 cal with 500 rounds.
The XP-36D had two .50s in the cowl and two .30s in each wing but weighed about 400lbs more than a standard P-36A.
The XP-36E had either three or four .30 cal guns in each wing and a non-operational .50 in the cowl but with the -13 engine speed dropped to 289mph.
Most of the export Hawks were not a lot heavier as you could trade three RCMG for the .50 in the cowl and it's 200 rounds were worth about 1000 round of the smaller ammo,
The XP-37 had an empty weight of 5272lbs, a designed useful load of 1,078lbs and design gross weight of 6350lbs (with 104 gallons of fuel).

All data from "Curtiss Fighter Aircraft" by Francis Dean and Dan Hagedorn. other sources may vary.

 

[Shortround6]

I think what sealed the fate of the P-40 was the D & E series aircraft. While very few Ds were built it had a "pie in the sky" armement set up that had no business on an 1200hp fighter.

"Normal" armament and load was four .50 cal guns with 250rpg which weighed 556lbs, However the "killer" was the alternative armament loads. provision had been made for 615rpg for a total of 2460 rounds or a total guns+ammo weight of 996lbs. throw in the provision for mounting a 20mm cannon under each wing (inplace of one of the machine guns or in addition to the two in each wing?) and the weight escalation in the rest of the plane was inevitable.
remember the 780lb wing on the fixed landing gear Hawk? it became a 1000lb wing on the early P-40s and went to about 1125-1132lbs on the P-40E and up.

Held up well to hanging large bombs (or multiple bombs) but at what cost?

The "structural" airframe weight of the Hawk had gone from 1696lbs on the fixed gear Hawk to 2499lbs (about 800lbs or 47%) with the "E", granted it got retracting gear but not all the weight was the retract mechanism. You do need bigger wheels and tires to hold up an over 8,000lb plane than you do a 5,500lb plane.

 

[Tkdog]

I think the cost was paid by the bomb load. There was a real need for fighter bombers and it was considered worth it to emphasize the bomb even if it meant the fight was reduced. A cover force of another type could provide top cover and the P-40s were dangerous once the bombs had been dropped. Not top shelf dangerous, but there was a significant self escort capability.