Dawncaster,
I have not done all the research yet to prove your graphs, but in
my opinion I think you did an awesome job putting them together
and posting them.
, Jeff
Thank you for appreciate!
Interesting try. To get a realistic estimation you need Brequet's equations.
In this particular case, given Propeller efficiency as a Calculated known as function of RPM and Hp and Prop diameter and effective Power Coefficient; Specific Fuel Consumption rates as function of HP and velocity for different Drag conditions; and accounting for decreased weights as fuel is consumed are knowns for each condition (3x external tanks, then 1x external tank as two are dropped, then clean except racks but full internal fuel load) change L/D as step functions - as 'Knowns', then you could estimate the Range.
You reduced your presentation to extracting Gallons per mile for some of the external conditions, but that doesn't take into account the necessary changes to propeller efficiencies, as RPM/Hp changes as fuel is consumed, to attain optimal SFC for optimal cruise. You didn't account for the Delta Drag except to 'pull' mile per gallon estimates. You didn't account for velocity changes as Hp and, therefore, SFC changed. You didn't account for the Change to CL as weight and Velocity changed to maintain optimal SFC at constant altitude.
The Brequet Equation is proportional to L/D, which changes as the external drag items go way to reduce Parasite Drag and lower Induced Drag. It is also directly proportional to Velocity/SFC which changes along the flight path.
Posted a few years ago but worth repeating.
Americas Hundred Thousand page 600.
P51 D
Fuel 269 US gallons internal + 2 75 gallon drop tanks = Combat Radius 700miles.
Conditions:-
Warm up and take off = 5 minutes normal rated power.
Climb to 25,000ft normal rated power no distance included.
Cruise out at 25,000ft at 210. I.A.S (about 315mph)
Drop tanks.
Cruise back at 25,000ft at 210mph I.A.S
30 minutes reserve at minimum cruise.
Combat 5 minutes Wep and 15 minutes Military power.
Takes no account for decreased fuel consumption during decent.
No allowance is made for formation flight or evasive action other than 20 minutes combat.
F4U-1 Corsair (no wing tanks) I.A.W. Pilots Manual page 50 and 63
Total fuel including 154 gallon drop tank 391 gallons.
Warm up and take off 18 gallons
Climb to 25,000ft 64 gallons ( difference split between Combat climb and Ferry climb)
Combat 5 minutes wep and 15 minutes military power 91 gallons
30 minutes reserve at minimum cruise = 21 gallons
Total = 194 gallons.
391-194 = 197
197 gallons at 315mph at max cruise at 26,000ft (82 gallons per hour) 197/82 = 2.4
2.4 * 315mph = 756
756/2 = 378 miles.
F4U-1 combat radius = 378 miles.
Or in other words 54% of a P51-D.
Mustang IV Full internal fuel + 2 imp 125 gall drop tanks, 2,690 miles at 20,000ft at 253mph
http://www.wwiiaircraftperformance.org/mustang/mustang-IV-ads.jpg
Corsair IV Full internal fuel + 2 137 imp gall drop tanks, 1,562 miles at 20,000ft at 261mph
http://www.wwiiaircraftperformance.org/f4u/corsair-IV-ads.jpg
Neil.
Good informations, Thank you!
It was a fun experience.
The ACP reflects the range at 1500 feet, but I did not think it could be used for combat sortie.
and also, felt something was lacking in writing.
both of you scratched that parts coolly.
it was itchy parts for me.
and I'm glad to know that the Corsair had a longer range with faster crusing speed than I expected.
according to ACP, -1 Corsair's best documented combat radius I knew was 555 miles even with two 150 gallon drop tanks.
in addition, it's altitude was just 15000 ft for vmax crusing out, and only 1500 ft for crusing back with 170 knots slow speed.
even considering condition was one drop tank was self-sealed and carried the entire distance, I always thought that Corsair's crusing performance was lacking to compared with ETO fighters which have high and fast cruise performances.
but 20000~26000 feet altitude? 400~500kph crusing speed? and yet acceptable range?
It was not so bad as I thought.
Goooooood.
Maximum Gross Weight for F4U-1 is theoretically 14,000 pounds, Empty Wt = 8980+ with WI; Basic Weight ~ 9670; Total Disposable Load ~ 4100 pounds. According to Dean's America's 100K, the highest table gross weight for F4U-1 was 13,900 with full internal 361 gallons of fuel, ammo and 175 gallon external tank. For F4U-4 the highest listed per Table gross weight at take-off was 14,700 pounds with 1000 pounds ordnance and 1x150 gallon C/L tank and full ammo
however, about take-off weight,
I have different information for it.
that F4U-1 seems the early type without pylons, so theoretically 14000 lbs was maximum take-off weight.
according world war II aircraft action reports,
even the -1 Corsairs operating on the carrier often used over 14000 lbs take-off weight.
500 lbs bomb.
1090 lbs for 150 gal drop tank.
1150 lbs for 8 x HVAR with racks.
this loadout is often used for Corsairs with carrier operation in 1945.
with 12175 lbs for F4U-1D's gross weight with two pylons.
total take-off weight is 14915 lbs.
if case of .50 cal ammunitions were not full, report stated 16500 rds .50 cal ammunitions used for 11 Corsairs, it means at least average 1500 rds .50cal ammunitions carried.
F4U-1D's full ammunition is 2400 rds, so subtract 270 lbs(weight of 900 rds of .50cal ammo).
14645 lbs, it's minimum take-off weight for this loadout.
and landbased corsairs, showed around 15000 lbs take-off weight.
2000 lbs for 2 x 1000 lbs bomb.
1220 lbs for 175 gal centerline drop tank.
this loadout is often used for land based Corsairs in 1945.
with 12175 lbs for F4U-1D's gross weight with two pylons.
total take-off weight is 15395 lbs.
if case of .50cal ammunitions was not full, assuming carried half of ammo(report stated no .50cal ammunitions used in sortie).
then subtract 360 lbs(weight of 1200 rds of .50cal ammo).
total take-off weight is now 15035 lbs.
and seems unpractical case, combat sortie without .50cal ammunitions.
but why not?
subtract 360 lbs again.
14675 lbs with no ammo, it's minimum take-off weight for this loadout.
now case of F4U-4, manual recommanded max 15800 lbs for take-off from runaway or catapulting.
there are a some pictures that might fit here, I have.
4 x 250 lbs bombs, 2 x 100 lbs bombs, 1000 lbs bomb, 1090 lbs drop tank, total 3290 lbs extra weight.
if their ammunitions and internal fuel tank were full, those F4U-4B's gross weight was approx 15700 lbs.
well, that pictures require the aircraft action reports for Korean War to prove above factors, so maybe not, but according to world war II action reports, most case, internal fuel tank was full filled before drop tank fitted for CV operation.
In addition, SAC stated F4U-4's maximum take-off weight was 16160 lbs.
Perhaps it's seems more close the theoretical maximum.
Improved performance of the F4U-4 provided better practical bomb load capacity over the F4U-1s.
but I think 1944 was the year of the Corsair with bombs.
At the time, there were many attempts to increase the F4U's bomb load capacity, and it's sometimes exceeded the existing limits, such as Lindberg's 4000 lbs bombs carrying which including a huge 2000 lbs bomb.
(Maj Haynes's Corsair of VMF-155, Kwajalein Atoll, 1944-08-27)
As a result of many attempts, after more precise limitations were found, such unpractical loadouts were rarely attempted in 1945.
especially for 2000 lbs bomb, it's only 22 times dropped in 1945 by VF type airplanes.
after long times, according to maunal, 2000 lbs bomb formally returned to the Corsair with F4U-5's centerline hardpoint. (F4U-4 had no centerline hardpoint for drop tank or bomb)
well, the limit load factor for all Corsairs even including AU-1 was 7.5G at 12000 lbs.
strength of the airframes were seems enough for all models.
and, not just by take-off power, maximum take-off weight was seems also affected by available take-off distance and hard points.
unpractical, but if the running distance or some conditions for take-off is given abnormally great, take-off weight could be higher than recommended maximum.
with the attempts in 1944, this is the source of early Corsair's bomb load capacity 'myth', I think.