ORIGINAL: adam_one
ORIGINAL: dick Hanson
More fodder
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My fiddlin around showed that watts n thrust were directly related.
the prop shape and sizes meant very little- ok, nuthin.
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Watts n thrust are indeed related but prop shape and size mean a lot regarding Power/Thrust ratio.
A smaller prop requires more power to produce the same thrust as a larger one.
For example, a 12x7 prop takes about 85W to produce 27 oz of thrust at 6000 RPM.
To produce the same thrust a 6x5 prop needs about 195W at 18,000 RPM.
OK, proove it-
I knew someone would drag in the theory on small n large in huge varuiations etc..
BUT I will stick to my original comment.
On my test stand which would swing up to 13" props only I could fus with all kinds of blades in roughly similiar diameters and pitch /etc., meant nuthin
In this case I saw a VERY similiar relationship of power input and the output in thrust.
Have you ever tested this?
Do you think I make this stuf up?
I actually TEST for it.
Since I can't read I have to rely on observed data.
Also- the differences in sizes you noted were huge -a completely different EFFICIENCY comparison.