1000-1200 HP: long range fighter vs. interceptor?

The Basket · Dec 27, 2018

Eh? I am not saying the Miles M.20 is any good. Quite the opposite. That's Kevin J pitch not I.

The Beaufighter can be also included as a long ranger fighter. Remember that in the 1930s bombers didn't need escort and it probably was not going to go up against an organised air defence network. Bombers in the Spanish civil war or Japanese bombers in China had no real issues.

British bombers were mainly for the bombing of empire subjects who didn't understand that the bombing was to teach them the import of civilization.

I remember reading that Blenheims were stuffed by Hurricanes and Spitfires in war games in the late 30s but it was too late and boy I bet it sucked. What works in 1934 gets no free rides in 1940.

Kevin J · Dec 28, 2018

The Basket said:
Eh? I am not saying the Miles M.20 is any good. Quite the opposite. That's Kevin J pitch not I.

The Beaufighter can be also included as a long ranger fighter. Remember that in the 1930s bombers didn't need escort and it probably was not going to go up against an organised air defence network. Bombers in the Spanish civil war or Japanese bombers in China had no real issues.

British bombers were mainly for the bombing of empire subjects who didn't understand that the bombing was to teach them the import of civilization.

I remember reading that Blenheims were stuffed by Hurricanes and Spitfires in war games in the late 30s but it was too late and boy I bet it sucked. What works in 1934 gets no free rides in 1940.

I'm saying that if the Miles M20 had first flown 2 years before with a Merlin X, the first production Merlin X was delivered Dec 5th 1938, then we have the basis for a single engine long range fighter to work with which could have escorted RAF bombers up to 200 miles without the use of drop tanks. Nb Germany is just across the border from France which was our ally. Later drop tanks can be added to extend its range. Unfortunately the RAF believed that the bomber would always get through. Flown in 1940 it becomes irrelevant as it has arrived to late. If you want a long range fighter in 1940 then you have the Mustang to work with and develop. The Miles M20 is only ever going to be a long range escort powered by a two speed Merlin probably only useful for the 1939/43 time period. After that, I guess you use them as bomb trucks like the P-40N, maybe even for teaching our natives the benefits of our Western civilisation after the Japanese had gone.

The Basket · Dec 28, 2018

Why would the RAF need a long range fighter in a 1930s scenario?
This is from a country in which the Folland Gnat was designed!!! Range was purely optional.

Kevin J · Dec 28, 2018

The Basket said:
Why would the RAF need a long range fighter in a 1930s scenario?
This is from a country in which the Folland Gnat was designed!!! Range was purely optional.

Agreed, but it would have been a good idea.

Shortround6 · Dec 28, 2018

Kevin J said:
The Miles M20 is only ever going to be a long range escort powered by a two speed Merlin probably only useful for the 1939/43 time period.

The M.20 is a dead duck against the Bf 109F and FW 190 in the Summer/Fall of 1941.

Kevin J · Dec 28, 2018

Shortround6 said:
The M.20 is a dead duck against the Bf 109F and FW 190 in the Summer/Fall of 1941.

Wasn't every other fighter plane in the World a dead duck too at this time against an Bf109F-4 and of course the Fw 190A, except of course the I-16, if you believe what the Russians had to say.

Shortround6 · Dec 28, 2018

Kevin J said:
Wasn't every other fighter plane in the World a dead duck too at this time against an Bf109F-4 and of course the Fw 190A, except of course the I-16, if you believe what the Russians had to say.

There is the enemy having the edge or an edge on you and being totally outclassed. A Spitfire V may not have been a dead duck but it needed a good pilot and good tactics, The British had given up trying with Hurricane II going up against the 109F and FW 190 over NW Europe Trying to use plane that was slower in level flight and slower in climb than a Hurricane II was not going to end up better.

As far as the I -16 even leaving out propaganda, The Russians themselves looked at combat results for a number of months in 1942 regarding the I-16, It had the fewest losses per sortie than any of their fighters at that time, it also shot down the fewest German planes and did the least damage to ground targets.
Keeping from being shot down is not winning the air battle, you have to shoot down enemy planes or at least prevent the enemy planes from performing their mission/s.

P-39 Expert · Dec 30, 2018

Take a P-39D/F, remove the .30 caliber wing guns (and the 100# nose armor plate) and there's your interceptor at 7100#.

Put fuel tanks for 50gal (25gal per wing) where the .30 caliber wings guns were, add a drop tank (75-110gal) and there's your escort fighter at 7400# with 170gal internal and 8000# with external tank. Same plane.

Kevin J · Dec 30, 2018

Shortround6 said:
There is the enemy having the edge or an edge on you and being totally outclassed. A Spitfire V may not have been a dead duck but it needed a good pilot and good tactics, The British had given up trying with Hurricane II going up against the 109F and FW 190 over NW Europe Trying to use plane that was slower in level flight and slower in climb than a Hurricane II was not going to end up better.

As far as the I -16 even leaving out propaganda, The Russians themselves looked at combat results for a number of months in 1942 regarding the I-16, It had the fewest losses per sortie than any of their fighters at that time, it also shot down the fewest German planes and did the least damage to ground targets.
Keeping from being shot down is not winning the air battle, you have to shoot down enemy planes or at least prevent the enemy planes from performing their mission/s.

I think using the Blenheim as a bomber over Western Europe was suicide, maybe Spitfire Vb's escorting Hurricane IIb fighter bombers was the only way, but outside Europe in the MTO or South-East Asia there's still some scope for a while for the Miles M20 to escort the Blenheim. In the Pacific it was Beauforts and Kittyhawks, which worked as far as I know. The Miles M20 with drop tanks needed to be in service in 1939, by 1940 its too late.

Kevin J · Dec 30, 2018

P-39 Expert said:
Take a P-39D/F, remove the .30 caliber wing guns (and the 100# nose armor plate) and there's your interceptor at 7100#.

Put fuel tanks for 50gal (25gal per wing) where the .30 caliber wings guns were, add a drop tank (75-110gal) and there's your escort fighter at 7400# with 170gal internal and 8000# with external tank. Same plane.

I agree that using the Cobra as an escort between 7000 and 8000 feet would be ideal, maybe even as an interceptor up to 12000 to 15000 feet.

Shortround6 · Dec 30, 2018

P-39 Expert said:
Take a P-39D/F, remove the .30 caliber wing guns (and the 100# nose armor plate) and there's your interceptor at 7100#.

Put fuel tanks for 50gal (25gal per wing) where the .30 caliber wings guns were, add a drop tank (75-110gal) and there's your escort fighter at 7400# with 170gal internal and 8000# with external tank. Same plane.

Hmmmm, P-39 with empty ammo boxes is so spin prone that instructions as stenciled on the ammo boxes says that ballast is to be carried if live ammo is not in the boxes for routine flights.

Yet the answer to improving the performance is to remove a hundred pounds from a point in the aircraft about 4 feet in front of the ammo boxes?
54% further away from the CG than the ammo boxes?

On the P-39Q the armor was 71 lbs The Q (and models right before it) used a larger, heavier prop than the Ds.
Possible the "armor" was a somewhat easy way to adjust the CG for different equipment?
If you need 70-100lbs of ballast as far forward in the nose as you can get it it is pretty clever to at least use it for something.

Lets see,

P-39D-2 goes 7697lbs with full .30 cal ammo and only 104 gallons of fuel in the tanks, and that is with a 140lb pilot and 20lb parachute.

Yanking 95lbs worth of guns, 260lbs worth of ammo and 100 lbs of armor magically gets you down to 7100lbs? another 142 lbs of "stuff" just magically disappeared from the plane?

splitting the difference between the 160 pilot allowance and the 200lb pilot allowance adds back in 20lbs, adding back in 16 gallons of fuel adds another 96lb s back in.

I really do love the part about cutting a hole in the wing to put the fuel in and running a few gas lines to connect the new 25 gallon tank in each wing to the rest of the fuel system at zero weight. Fuel tanks, even ones that are not self sealing do weight something. Thin/flat self sealing tanks weigh a lot for the amount of fuel held inside.

empty 75 gallon sheet metal drop tank weighed 46lbs.

Please note than many P-39s were operated with 300rpg for the .30 cal wing guns and saved about 180lbs that way while keeping the wing guns. so leaving the guns (95lbs) and 300rpg (78lbs) only costs 173lbs.

Reluctant Poster · Dec 30, 2018

Shortround6 said:
Hmmmm, P-39 with empty ammo boxes is so spin prone that instructions as stenciled on the ammo boxes says that ballast is to be carried if live ammo is not in the boxes for routine flights.

Yet the answer to improving the performance is to remove a hundred pounds from a point in the aircraft about 4 feet in front of the ammo boxes?
54% further away from the CG than the ammo boxes?

On the P-39Q the armor was 71 lbs The Q (and models right before it) used a larger, heavier prop than the Ds.
Possible the "armor" was a somewhat easy way to adjust the CG for different equipment?
If you need 70-100lbs of ballast as far forward in the nose as you can get it it is pretty clever to at least use it for something.

Lets see,

P-39D-2 goes 7697lbs with full .30 cal ammo and only 104 gallons of fuel in the tanks, and that is with a 140lb pilot and 20lb parachute.

Yanking 95lbs worth of guns, 260lbs worth of ammo and 100 lbs of armor magically gets you down to 7100lbs? another 142 lbs of "stuff" just magically disappeared from the plane?

splitting the difference between the 160 pilot allowance and the 200lb pilot allowance adds back in 20lbs, adding back in 16 gallons of fuel adds another 96lb s back in.

I really do love the part about cutting a hole in the wing to put the fuel in and running a few gas lines to connect the new 25 gallon tank in each wing to the rest of the fuel system at zero weight. Fuel tanks, even ones that are not self sealing do weight something. Thin/flat self sealing tanks weigh a lot for the amount of fuel held inside.

empty 75 gallon sheet metal drop tank weighed 46lbs.

Please note than many P-39s were operated with 300rpg for the .30 cal wing guns and saved about 180lbs that way while keeping the wing guns. so leaving the guns (95lbs) and 300rpg (78lbs) only costs 173lbs.

According to the paper attached no one who weighed more than 160 lbs would be accepted for training as a fighter pilot. Also they had to be between 64" and 69" in height. Other pilots could be up to 76" and 200 lbs.

Shortround6 · Dec 30, 2018

Reluctant Poster said:
According to the paper attached no one who weighed more than 160 lbs would be accepted for training as a fighter pilot. Also they had to be between 64" and 69" in height. Other pilots could be up to 76" and 200 lbs.

That maybe so, but the weight allowance of the P-39 (at least in the early models) of 160lbs included a 20 pound parachute. While P-39 pilots in the South Pacific may have flown in shorts, a short sleeved shirt and low cut shoes that wasn't going to work in other climates. Throw in the Mae West life preserver and your 160lb pilot (in his skivvies ) dressed, ready to go in a cold area could come close to 200 lbs with the parachute. The 20lbs for the parachute was included in the later 200lb pilot allowance so even in a hot area you weren't officially going to get a 200lb pilot

P-39 Expert · Dec 31, 2018

Shortround6 said:
Hmmmm, P-39 with empty ammo boxes is so spin prone that instructions as stenciled on the ammo boxes says that ballast is to be carried if live ammo is not in the boxes for routine flights.

Yet the answer to improving the performance is to remove a hundred pounds from a point in the aircraft about 4 feet in front of the ammo boxes?
54% further away from the CG than the ammo boxes?

On the P-39Q the armor was 71 lbs The Q (and models right before it) used a larger, heavier prop than the Ds.
Possible the "armor" was a somewhat easy way to adjust the CG for different equipment?
If you need 70-100lbs of ballast as far forward in the nose as you can get it it is pretty clever to at least use it for something. Just move the radios from the tail cone to right behind the pilot, solves the CG problem when removing the nose armor.

Lets see,

P-39D-2 goes 7697lbs with full .30 cal ammo and only 104 gallons of fuel in the tanks, and that is with a 140lb pilot and 20lb parachute.

Yanking 95lbs worth of guns, 260lbs worth of ammo and 100 lbs of armor magically gets you down to 7100lbs? another 142 lbs of "stuff" just magically disappeared from the plane?

splitting the difference between the 160 pilot allowance and the 200lb pilot allowance adds back in 20lbs, adding back in 16 gallons of fuel adds another 96lb s back in.

I really do love the part about cutting a hole in the wing to put the fuel in and running a few gas lines to connect the new 25 gallon tank in each wing to the rest of the fuel system at zero weight. Fuel tanks, even ones that are not self sealing do weight something. Thin/flat self sealing tanks weigh a lot for the amount of fuel held inside. The weight of the actual tanks would be offset by the removal of the gun mounts, chargers, heaters and ammunition boxes. No need to "cut a hole" for the new tanks, the space was already there.

empty 75 gallon sheet metal drop tank weighed 46lbs.

Please note than many P-39s were operated with 300rpg for the .30 cal wing guns and saved about 180lbs that way while keeping the wing guns. so leaving the guns (95lbs) and 300rpg (78lbs) only costs 173lbs.

See above for the CG solution and weight of fuel tanks.

The P-39D/F (not the D-1 or D-2) weighed 5462/5409 empty. Add 1700# load (pilot 200#, oil 70#, remaining armor plate and glass 130#, fuel 720# for 120gal, guns/ammo 580# for a 37mm cannon, 2x.50cal MGs and gun sight) gets you to 7162#/7109# for the D/F. Climb and operating heights are greatly improved at this weight.

Shouldn't be too hard to design fuel tanks to replace the wing guns/ammunition for the long range model.

Shortround6 · Dec 31, 2018

P-39 Expert said:
See above for the CG solution and weight of fuel tanks.

Shouldn't be too hard to design fuel tanks to replace the wing guns/ammunition for the long range model.

it is not hard to design fuel tanks to fit in the gun/ammo spaces in the wing. it is very hard designing/building such tanks to be weightless.

The Fuel system in the early Airacobras went about 290lbs for the 120 gallon tanks with self-sealing. The system would include tanks, lines, drains, fills, valves and such.

In the Airacobra there were 6 interconnected heavy rubber fuel cells in each wing. On the 87 gallon models they left out two bags in each wing. They just didn't not fill the two out outer tanks/bags. They were trying to reduce the weight of plane by not only reducing the weight of the fuel but by reducing the empty weight of the plane.

Empty weight of the tanks out in the wings in the machine gun bays could be 100lbs or more, or the weight of the .30 cal you want to take out.

Please note that on the P-40L they took out a 37 gallon (?) tank and saved about 100lbs. Flat thin tanks weigh more per gallon of contents.

Since it appears the whole idea of the extra wing tanks is to give the P-39 extra endurance/range after the drop tank is gone and to have that extra endurance the tanks have to have fuel in them (150lbs in each tank if full) and the fuel weighs more than the ammo you took out (way more if the planes were flying with 300rpg) I have trouble figuring out why we should use the lighter figure of no guns when estimating this "escort fighters" performance.

AS for the gear box armor, why did it stay when they took out all kinds of other stuff?

About the only time they took it out was an experimant with a really stipped P-39 at the Bell factory where they saved just under 1300lbs. Great performance but they took out not only the gear box armor but the oil tank armor, the radios, the oxygen equipment most of the flight instruments (the left the airspeed indicator, the altimeter and some engine gauges) half the fuel cells, all ballast, etc.

P-39 Expert · Dec 31, 2018

Shortround6 said:
it is not hard to design fuel tanks to fit in the gun/ammo spaces in the wing. it is very hard designing/building such tanks to be weightless.

The Fuel system in the early Airacobras went about 290lbs for the 120 gallon tanks with self-sealing. The system would include tanks, lines, drains, fills, valves and such.

In the Airacobra there were 6 interconnected heavy rubber fuel cells in each wing. On the 87 gallon models they left out two bags in each wing. They just didn't not fill the two out outer tanks/bags. They were trying to reduce the weight of plane by not only reducing the weight of the fuel but by reducing the empty weight of the plane.

Empty weight of the tanks out in the wings in the machine gun bays could be 100lbs or more, or the weight of the .30 cal you want to take out. All 12 of the original self sealing fuel tanks only weighed 240#. Two more will weigh 100#? Like I said before, the weight of the actual new tanks will be offset by the removal of the gun mounts, chargers, heaters and ammunition boxes, largely a wash.

Please note that on the P-40L they took out a 37 gallon (?) tank and saved about 100lbs. Flat thin tanks weigh more per gallon of contents.

Since it appears the whole idea of the extra wing tanks is to give the P-39 extra endurance/range after the drop tank is gone and to have that extra endurance the tanks have to have fuel in them (150lbs in each tank if full) and the fuel weighs more than the ammo you took out (way more if the planes were flying with 300rpg) I have trouble figuring out why we should use the lighter figure of no guns when estimating this "escort fighters" performance. The interceptor version weighed 7100#, the escort version with the extra 50gal fuel weighed 7400#.

AS for the gear box armor, why did it stay when they took out all kinds of other stuff? Who knows? I believe it was for ballast, since it was located in the nose and was too far from the pilot to do much good, especially when the pilot was already protected from the front by different armor plate and armor glass. The designers had to allow for variables like larger (heavier) propellers (probably a 4 blade prop in final versions) and the possibility of a mechanical second stage aft of the engine. Again, just remove this nose armor and move the radios up from the tail cone to behind the pilot to restore balance.

About the only time they took it out was an experimant with a really stipped P-39 at the Bell factory where they saved just under 1300lbs. Great performance but they took out not only the gear box armor but the oil tank armor, the radios, the oxygen equipment most of the flight instruments (the left the airspeed indicator, the altimeter and some engine gauges) half the fuel cells, all ballast, etc.

See above.

1000-1200 HP: long range fighter vs. interceptor?

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