Hlbly, I'll throw you a bone. Your numbers or our numbers are inconsequential in relationship to the logic you've laid out. Not picking on you but your claim about the Buffalo being "wrong" in AH is like the 10,000th claim that "something is amiss in the land of Denmark". It follows a familiar pattern: IF it doesn't fly in a way I expect or can explain it THEN the FM must be wrong.
Here's the problem. Just because you can't explain it doesn't mean that it's wrong. Like the past 10,000 other claims has it occured to you that maybe what's wrong is not the FM but your understanding of the physics? That's why to prove something is wrong it's not enough to make observations. You need to EXPLAIN the logic behind the conclusions you made about your observations.
In your last post you finally revealed some of your logic. The FW190A-8 has greater horsepower (thus greater thrust) and a lower drag compared to the B-239 therefore the FW190A-8 should out accelerate the B-239. Sounds logical. However there a couple of problems with this that I've been throwing hints at to get you to think about them. Let's explain.
Let's use a simplistic example assuming fixed thrust & drag to demonstrate. We have two airplanes:
Plane A: weight=8,900 lbs, thrust=2,500 lbs, drag=525 lbs
Plane B: weight=4,400 lbs, thrust=1,800 lbs, drag=725 lbs
Which airplane accelerates faster than the other? Basis your logic Plane A would because it has greater thrust and lower drag. This would be wrong however because Plane B actually accelerates faster.
Plane A: a=7.1 ft/s^2
Plane B: a=7.9 ft/s^2
Why? Acceleration in the direction of flight in level flight simplifies to:
a = (thrust-drag) / mass
So the first problem in your logic is that you've only factored in thrust and drag in your assessment but not mass. Ignore variables at your peril because they will bite you in the butt. So acceleration is a function of thrust, drag, and mass and as you can see in our example mass can make a difference. How much of a difference does the mass make? That leads to the 2nd problem with your original logic.
To know how much of a difference mass makes on acceleration you also have know the VALUES of thrust and drag as well. Both thrust and drag are non-linear for our piston-prop airplanes and vary with velocity. In other words they change in way that makes generalized statements like "thrust is greater, drag is less" between planes meaningless unless you specify where in the flight envelope you're talking about. So the 2nd problem is that you have to factor in the non-linear changes of thrust, drag, and thus also the non-linear changes in acceleration before you can even know if one plane out accelerates another over a portion of the flight envelope.
"Young cat! If you keep your eyes open enough, oh the stuff you will learn! The most wonderful stuff....The more that you read, the more things you will know. The more that you learn, the more places you'll go." (I Can Read With My Eyes Shut - Dr. Seuss)
Tango
412th FS Braunco Mustangs
