HumanPoweredDesigner
Well-Known Member
Is my guestimation true: That while a bigger propeller gets much more static thrust than a small one, the big ones thrust drops off much more quickly as airplane speed increases?
I would think if two engines have the same power, but different sized props, maybe the thrust of the small prop would go from 100 pounds to 80 at cruise speed, but the big prop would go from 200 to 90, or something like that.
This is because the speed of the incoming air is smaller compared to how much the prop accelerates the air.
So I'm just wondering how much of an advantage a bigger prop would actually have for a 20 hp engine at 60 mph. Say, 36" vs 48" or 60".
I would think if two engines have the same power, but different sized props, maybe the thrust of the small prop would go from 100 pounds to 80 at cruise speed, but the big prop would go from 200 to 90, or something like that.
This is because the speed of the incoming air is smaller compared to how much the prop accelerates the air.
So I'm just wondering how much of an advantage a bigger prop would actually have for a 20 hp engine at 60 mph. Say, 36" vs 48" or 60".
