I don't know! I didn't intentionally "dislike" your post. I will "undislike" it.
Cheers
Steve
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Doh
What have I did wrong, Steve?
In order not to clog another thread, here are engine powers at 20000 ft (~ 6km) for some widely-used engines in 1939-41 time frame; no ram effect:
Merlin III: 890
Merlin X: ~925
Merlin XII: ~945
Merlin XX: 1060 (similar for Mk.45)
DB 601A: 800 (similar for Italian and japanese copies; over-revving to 2600 and later to 2800 improved this figure for 601A)
DB 601N: 1020
DB 601E: 1030 (improved to 1130 from late 1941 on)
BMW 801C: 1200
V-1710-33: 860 (similar with -39)
1941:
V-1710 turbo: 1150
R-1830 and R-1820 turbo: 1200
...
Merlin XX output was 1175hp at 20500ft (Hurricane IIA)
In order not to clog another thread, here are engine powers at 20000 ft (~ 6km) for some widely-used engines in 1939-41 time frame; no ram effect:
Merlin III: 890
Merlin X: ~925
Merlin XII: ~945
Merlin XX: 1060 (similar for Mk.45)
and all
R-1830 and R-1820 turbo: 1200
Was looking at the P-40F manual and saw a few numbers that bear on this. for instance take-off of our hypothetical fighter.
A clean P40-F at 7500lbs
...
At 9300lbs but clean it needs 13.3 minutes and 44 gallons of gas to get to 20,000ft.
Adding hundreds of pounds to 1000-1200hp fighters could affect take-off (can't use existing fields) and initial climb out to the extent you aren't going to get the range increase you might think?
What I was trying to get at is disproportionate increase in take-off distances and times to altitude (and fuel used to get there) that is caused by a 24% increase in weight (7500lbs to 9300) or even a 9.5% increase in weight (8500-9300lbs) and that is with the most powerful engine in the group and using 100/130 fuel.
clean the increase in weight of 9.5% meant 12.8% more fuel used and 25% more time for the P-40F
With the drop tank (one) the same weight now means 30% more fuel and 65% more time.
for the engines involved it also helps to the take-off power and the climb power.
.........................................take-off...................climb......................power at 20K
Merlin III..........................880..................990/12,000ft.............................. 890
Merlin X: .......................1065................1035/2250ft..................................925
Merlin XII:.......................1175.............NP +9 2850rpm............................945
Merlin XX: ......................1280.............1125/9,500 MS............................1060 (similar for Mk.45)
DB 601A: ......................1100...............910-990.(30 min) ........................800
clones............................1175.................??????.............................................850?
DB 601N:........................1175..............1020-1050................................... 1020
DB 601E:.........................1375..............1000-`1040.................................. 1030/1130
V-1710-33:....................1040..................930................................................. 860 (similar with -39)
V-1710-39.....................1150..................1000................................................860?
1941:
V-1710 turbo: ..............1150.................1000..............................................1150
R-1830 and
R-1820 turbo: .............1200..................1000..............................................1200
Open to correction. Climb ratings are either 30 minute or continuous and are sea level through medium (in this case 10-15,000ft??) altitude.
Merlin III, X DB 601s (except N) are with 87 octane. American engines are with 100/100. later British engines are with 100/115-120 or 100/130 fuel.
heavily loaded fighters are going to need big airfields and burn some of their extra fuel just getting to the desired altitudes.
Performance at altitude may be much poorer (or a greater difference) than comparing times to altitude might suggest.
-Wonder if someone can come up with a viable escort fighter on 1000-1200 HP (at 20000-15000 ft of altitude; historical engines only)
-Obviously, the time of interest would be the 1st years of the war (only for hypothetical fighters).
Depending what the vague "1st years" means, my choice would be:
Early P-51, but with the DB601 and 3xMG151/20
Weight, or wing loading, was a killer when it is about take off, the increase of take-off power was able to cancel that just by that or this percentage. We have Spitfire V with 1185 HP for take off, yet it can took off from aircraft carries when it was overloaded with fuel for ferrying.
On 100 oct fuel, Merlin X was good for ~1280 HP for take off (no jiggery-pokkery, manufacturers values).
Yes it could, but that brings us back to when you start the design, The British had annouced at the Paris Air show in Nov 1938 that they expected to get 1300hp from the Merlin VIII for take off on 100 octane, and 1145hp at 16,750ft in high gear on the Merlin X.
Italian copy of DB 601A was supposedly good for 1050 PS at 4.5 km, vs. DB 601A (the one with better S/C) was good for 1020 PS at 4.5 km. At 20000 ft, the respective powers are perhaps 820 HP vs. 800?
Fighter with plenty of fuel can switch to drop tanks at 10000 ft, thus not draining it's internal tanks too much.
They could switch at 5000ft or less, whatever it took to turn around and land back at the airfield should the engine quit when switching over.
Point was that while yes, you are extending the range, you are also burning up 5-10% of your expanded fuel capacity (however stored) just getting to operational altitude.
The Mustang had the power (and aerodynamics) to blast it's way to 25,000ft carrying a pair of 75 gallon drop tanks (330 gallons total) in 16 minutes and use 60 gallons from startup using military power.
Climb at 20,000ft or so is really affected by either power or weight.
Power for climb is the power left after you take out the power needed for straight and level flight at the altitude in question.
Just to illustrate the point lets say Plane X needs 200hp to move along 20-30mph faster than stalling (actually needs less power that right at stall speed) and at this height it has one of the 800hp engines, it has 600hp to devote to climb (low speed but high angle?) while if Plane X had a 1000hp engine it would have 800hp available for climb. a 33% increase in avialbel power vs the 25% increase the raw number gives us.
It is this "net" number that we need to use (or approximate) when figuring performance of our "loaded" escort fighters. Speed is not affected much by extra internal fuel but climb and turning ability is, not turning radius on it's own but the ability to turn and maintain altitude or turn and climb at the same time.
Yes it could, but that brings us back to when you start the design, The British had annouced at the Paris Air show in Nov 1938 that they expected to get 1300hp from the Merlin VIII for take off on 100 octane, and 1145hp at 16,750ft in high gear on the Merlin X.
Italian copy of DB 601A was supposedly good for 1050 PS at 4.5 km, vs. DB 601A (the one with better S/C) was good for 1020 PS at 4.5 km. At 20000 ft, the respective powers are perhaps 820 HP vs. 800?
First 24 months, perhaps - until Sept 1st 1941.
That rules out P-51 as base due to being too late...
Much as I like the Whirlwind and think it got a bad deal, but it was never going to be a long range fighter. It was two small an airframe for two engines and enough fuel to fly long ranges.If you want a long range fighter then the Whirlwind would have been okay if the engines had a better high altitude performance or it could take Merlins without too many mods, so that leaves you the Gloster F9/37 which was powered by either Taurus or Peregrines. The advantage of the Gloster over the Whirlwind is that it has lots of wing area to support Merlins and extra fuel. The Germans have the Fw 187, the Americans the Lightning.
Again, you must be more specific. First flight of the prototype, first production , introduction to service, first combat, what ?
Service date, in case one wants to mix & match historical A/C and parts (engines, armament, hi-lift devices etc) together.