Clay_Allison
Staff Sergeant
- 1,154
- Dec 24, 2008
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
I've considered that and it sounds like a decent idea too.Well, here's an interesting idea:
The P-40's direct predecessor was the P-36. Perhaps a little modifying would bring the P-36 up to the Bf109 Spit's level easier than it would be to trim the P-40 down.
The P-36 was 5,650 pounds loaded. Perhaps replace the P&W R-1830-17 (1,050 horse) with a R-1830-92 (1,200 horse) or R-1830-94 (1,350 horse) and upgrade the armament?
I think most of us have seen pictures of the P-40 alongside the Bf-109 and the Supermarine Spitfire and most of us can agree that they are not that much different in size, unless I'm blind, the P-40 looks pretty small compare to the P-51 etc.
My question is: If they started in April 1939 systematically cutting weight off the P-40, could they have gotten it down to a loaded weight of 6,500 pounds, and could they have done it by January 1942? The P-40 had a lot of steel armor, probably two more guns than it really needed, and a lot of steel structure that could be replaced with Aluminum (maybe?).
It performed adequately against the Japanese, but in North Africa that famous ruggedness was less effective versus German cannon. The toughness aspect of early war US planes is under-appreciated but it seems to me that the key is not getting shot in the first place. Replacing steel structure with aluminum and dropping a lot of the armor (all but the pilot's back plate).Perhaps you do need to see the eye doctor
P-40E wing span and area: 37.33 ft and 235.94 ft²
P-51D wing span and area: 37 ft 0 in and 235 ft²
P-40E length and weight: 31.67 ft and 6,350 lb
P-51D length and weight: 32 ft 3 in and 7,635 lb
Numbers are from Wiki and weights are empty. P-51s engine is several hundred pounds heavier.
A P-40 C (deliveries start April of 1941) weighed 5812lb empty equiped and 7549lbs loaded. Two .50s with 380 rounds per gun and four .30s with 490 rounds per gun. It did carry 160 US gallons of fuel?. .30 cal ammo wieghs about 1/4 of what .50 cal ammo does. .30 cal guns weigh about 1/3 of a .50.
you need to cut about 1000lbs from the P-40C. you could cut some armament (not a lot) , you could cut fuel and range/endurance.
If you cut structure you loose the ruggedness the P-40 was known for. Cutting armour makes the plane vulnerable to Japanese 7.7mm MGs.
I'd only be willing to part with the SS tanks if you could feed exhaust into them to prevent fire. (several planes used this system, it seems to have worked well)we can put out no more that all the .30 and half fuel for ~700 pounds no more
w/o wing weapon we have also manuvreability benefit
original p-40 weight ~6800 pounds i think no armour no ss tanks
2x20mm H.S.404 cannon would be probably an ideal armament. We should have put more emphasis on getting that gun working from the beginning, so adding that to the lightening project is a wise move. (it would also have the effect of better arming our other fighters. imagine a 6x20mm battery on the thunderbolt or 4 on the lightning).M2 Browning machine gun - Wikipedia, the free encyclopedia
.50cal MG weighs 38kg
6 x .50cal MG weigh 228kg
MG 151 cannon - Wikipedia, the free encyclopedia
MG151/20 cannon weighs 42kg
2 x MG151/20 cannon weigh 84kg.
Replacing the 6 x .50cal MGs with a pair of decent 20mm cannon would probably save weight and also increase overall firepower. However the weight savings is small potatoes compared to overall aircraft weight.
It performed adequately against the Japanese, but in North Africa that famous ruggedness was less effective versus German cannon. The toughness aspect of early war US planes is under-appreciated but it seems to me that the key is not getting shot in the first place. Replacing steel structure with aluminum and dropping a lot of the armor (all but the pilot's back plate). .
Actually, it seems like the P-40N is exactly what I'm talking about. If they had started in 1939 with a "hot rod" P-40 in mind rather than having to wait until the summer of 1943 to decide they needed it. The 'N' got down to 7400 pounds in seemingly only a few months and without appearing to interrupt delivery schedules. Shedding another 400 pounds with a year and a half to work on it should have been quite possible.
I agree. However .50cal machineguns also need accessories and ammunition. I suspect that including weight for these items simply tilts the advantage even more in favor of using a pair of 20mm cannon.
They put 8(!) 30 cals and two 50s and 65 pounds of armor on the XP-46, in addition to 65 pounds of armor and self-sealing tanks.Well, if you make the airframe smaller you have an XP-46.
The stripped prototype did 410mph at 15,000ft but the version with guns, armour and self seaing tanks only mangaged 355 at 12,200ft.
How many fewer guns, how much less armour and how much less protected fuel would get you to a a "Half-way point" say 380mph I don't know.
XP-46 also had an intial climb rate of about 2,460fpm.
It did weigh 5625lb empty and grossed 7,322lb.
They put 8(!) 30 cals and two 50s and 65 pounds of armor on the XP-46, in addition to 65 pounds of armor and self-sealing tanks.
I'd be willing to go with 4x.50MG or 2x20mm and exhaust-suppressed fuel tanks rather than self-sealing. The XP-46 was working with an 1150 horse version of the Allison, it could have continued to get better as they kept adding horsepower to the design.
Yes, and that gets the plane down to 7.000 pounds, 1200 pounds lighter than the P-40E. You probably have a 375 MPH top speed with room to add later dash numbers of the Allison engine and "high activity" Hamilton Standard props (like the P-47) as the war progresses.So what are you going to save in total? 350-400lbs?