Context for values in SAC charts?

[Spindash64]

I've been trying to dig into the "Standard Aircraft Characteristics" charts for data, but it occurs to me that there is no mention of whether Vstall on the sheet is in a clean configuration, with flaps down, gear up, with flaps AND gear down, or some other configuration. I'm aware landing gear shouldn't have an enormous impact on stall speed, but you understand my point. It's a somewhat important bit of context. They list different values for different weights, but no mention of different flap settings


In addition, looking at the sheet for the F4F-4 (right here), adding empty weight, fuel weight (assuming around 6lbs per gallon gasoline and 7.5lbs per gallon of oil), the result is over a thousand pounds lighter than the listed "loaded weight". At most, I can't see the pilot + his gear weighing more than 200lbs, so I'm not sure where the missing 800lbs or so went. Some of that is likely ammunition, but I'm not sure if that would account for the remaining weight: assuming the 62lbs per AN/M2 weight that Wikipedia suggests, and the fact that the FM-1 is supposedly 75lbs heavier, that would mean that 280 rounds of ammunition is roughly 75+62+62 = 200lbs, which is around 2/3 a pound per .50 cal round. I'm not sure if that's correct or not

 

[FLYBOYJ]

I've been trying to dig into the "Standard Aircraft Characteristics" charts for data, but it occurs to me that there is no mention of whether Vstall on the sheet is in a clean configuration, with flaps down, gear up, with flaps AND gear down, or some other configuration. I'm aware landing gear shouldn't have an enormous impact on stall speed, but you understand my point. It's a somewhat important bit of context. They list different values for different weights, but no mention of different flap settings


In addition, looking at the sheet for the F4F-4 (right here), adding empty weight, fuel weight (assuming around 6lbs per gallon gasoline and 7.5lbs per gallon of oil), the result is over a thousand pounds lighter than the listed "loaded weight". At most, I can't see the pilot + his gear weighing more than 200lbs, so I'm not sure where the missing 800lbs or so went. Some of that is likely ammunition, but I'm not sure if that would account for the remaining weight: assuming the 62lbs per AN/M2 weight that Wikipedia suggests, and the fact that the FM-1 is supposedly 75lbs heavier, that would mean that 280 rounds of ammunition is roughly 75+62+62 = 200lbs, which is around 2/3 a pound per .50 cal round. I'm not sure if that's correct or not

Why not explore the official flight manual?

F4F Manual Book

Many thanks smeagol_to_others, I uploaded here for those that wish to download from here. Thanks again!!!!

ww2aircraft.net

 

[Spindash64]

Not seeing if those are the calibrated numbers or indicated. Also, those are for the FM-2, which is lighter. I DO need data for the FM-2 as well, but there's also no mention of what weight these numbers were obtained at

 

[FLYBOYJ]

Not seeing if those are the calibrated numbers or indicated. Also, those are for the FM-2, which is lighter. I DO need data for the FM-2 as well, but there's also no mention of what weight these numbers were obtained at

I believe most of the time those numbers are based on indicated airspeed (unless indicated) and you're going to find many WW2 flight manuals lacking in that data, why this is not indicated in this flight manual is anyone's guess, my feelings is the differences might be within a few knots of the numbers shown in that chart and is an average of weights. If you read further in the manual, it indicates an 85 knot approach speed. Now I have a P-38 flight manual and stall speeds are indicted under 3 aircraft weights and the difference between the lowest figure and highest figure is about 9 mph. In a training manual for the P-47N, again nothing is mentioned about stall speeds based on weight but does indicate speeds the aircraft should be flown when entering the pattern to land.

 

[eagledad]

Gentlemen

Pilot handbook for F4F-4 can be found at

F4F Manual Book

Hello! I'm searching for Grumman F4F Wildcat Manual Book. I'll be very thankful for any help. Chris

ww2aircraft.net

The hanbook gives stall speeds both clean and dirty.

Eagledad

 

[PStickney]

Why not explore the official flight manual?

View attachment 680813

View attachment 680814

F4F Manual Book

Many thanks smeagol_to_others, I uploaded here for those that wish to download from here. Thanks again!!!!

ww2aircraft.net

Be a bit leery about those numbers - while they're accurately derived from flight test data - individual airplanes can vary quite a bit - surface condition - dents, scuffs, dead bugs, state of rigging, will vary your lift and drag coefficients by 5% or more. While the numbers can be backed up, they should always be viewed as guidelines (Anybody reporting .1 of a knot is being overly precise) The same goes for engine and propeller performance.

 

[FLYBOYJ]

Be a bit leery about those numbers - while they're accurately derived from flight test data - individual airplanes can vary quite a bit - surface condition - dents, scuffs, dead bugs, state of rigging, will vary your lift and drag coefficients by 5% or more. While the numbers can be backed up, they should always be viewed as guidelines (Anybody reporting .1 of a knot is being overly precise) The same goes for engine and propeller performance.

True, but they are the "official" document that pilots are to follow and I can almost bet dollars to donuts that this was considered when the aircraft were accepted after production test flights and when they were operational within a squadron. 42 years in commercial and military aviation, I've dealt with many issues when a pilot was not seeing -1 numbers.