B-25 take-off distance

[Trilisser]

Folks, the B-25J pilot manual posted on this site states that at a TO weight of 32,000 lbs the ground roll in zero wind conditions is 3300 ft.

Yet, the USN Standard Aircraft Characteristics data sheet states that a PBJ-1H with a gross weight of 35,105 lbs requires only 1495 ft to take-off in zero wind conditions.

Given the B-25's reputation for short TO the first data appears dubious as it is about as long a distance as that of a heavily loaded Lancaster!

 

[Lighthunmust]

At what airfield temperatures and altitudes were the distances determined? Those are two of several factors affecting takeoff distance. We have takeoff crashes in Arizona quite frequently due to pilot failure to pay attention to density altitude.

 

[Greyman]

I've got an A&AEE trial for just such a thing:

Mitchell I (FK162) - 2 x Cyclone GR.2600-9
29,000 lb - 22½° flap setting - 2600 rpm - 44 in HG

Wind: 5 ft per sec - Temp: +9°C - Ground Barometric Pressure: 29.83 in HG
Take-off Run: 430 yards (105 ASI)
Distance to Clear 50 ft obstacle: 815 yards (115 ASI)

Corrected to zero wind and standard atmosphere
Take-off Run: 495 yards (105 ASI)
Distance to Clear 50 ft obstacle: 920 yards (115 ASI)

 

[Trilisser]

Thanks Greyman! There is significant differences between those A&AEE values and the Pilot's Manual (B-25D but the manual for the -J seems to give the same data). At 28,000 lbs the manual gives (sod-turf runway, corrected to standard atmosphere) a 960 yds ground roll and 1265 yds to clear 50 ft.