F4U-4 Climb

[F4UDOA]

Just got done tested the F4U-4 climb to 10K. Seems kinda doglike considering every published report I have seen.

I used auto takeoff. Leveled as soon as runway departure and accelerated to 160MPH(F4U-4 best climb speed) and hit auto climb. After a momentary Zoom it leveled at below 3,500FPM never sustaining any higher than 3,800FPM as AH charts indicate. Then a rapid drop to roughly 3,300FPM full WEP up to 10K.

What gives?

Here is the AH chart



Here is the NAVAIR Doc for the April 1945.



At least it should be able to sustain 3800FPM at sea level where most of the action in AH takes place.

[Regurge]

Try using wind (downdraft) to test climbrate at specific alts. Adjust windspeed untill VSI reads zero, that windspeed is then the effective climb rate.

I tried this with the -4. At about 100' agl, a 43 mph downdraft (.wind 0 0 0 -43) kept it in level flight. That works out to 3784 fpm.


Now the -1 is a different story. It climbs at about 2650fpm at sea level, where the AH charts sday it should do ~2850. I posted this in the bug reports forum some time ago but there was no response.

[Sikboy]

Originally posted by F4UDOA
Just got done tested the F4U-4 climb to 10K. Seems kinda doglike considering every published report I have seen.

I used auto takeoff. Leveled as soon as runway departure and accelerated to 160MPH(F4U-4 best climb speed) and hit auto climb. After a momentary Zoom it leveled at below 3,500FPM never sustaining any higher than 3,800FPM as AH charts indicate. Then a rapid drop to roughly 3,300FPM full WEP up to 10K.

Out of curiosity, did the autoclimb maintain the 160mph which is your "best climb speed"? I've noticed that the auto climb likes to zoom up to bleed speed, then settles in at a slower climb. Have you tried timing this while manually climbing up to 10k, while maintinaing 160mph?

-Sikboy

[F4UDOA]

Regurge,

How in the heck did you calculate that??

Could you show me how you did that so I can duplicate this with other A/C??

[F4UDOA]

Regurge,

How in the heck did you calculate that??

Could you show me how you did that so I can duplicate this with other A/C??

[Regurge]

You mean how to convert mph to fpm?

Take your mph number and multiply by 5280 (number of feet in a mile). That gives you feet per hour. Then divide by 60 and you have feet per minute.

Or you could just do it in one step and multiply mph by 88.

[F4UDOA]

Err,

No.

How did you get from a 100 degree angle and a 40Mph wind to determine how many fpm an a/c is climbing?

Never mind, I just figured it out.