Originally Posted by
combatpigg
What I'm really curious about are the ratios that the top flyers use
What triggered this curiosity was recently looking through APCs prop catalog.
Whenever they list a prop with a decimal point in the diameter number you can bet it's a competition / specialty prop.
When I saw they sell a 11.5 x 4 ....my guess was that it was for CL stunt. [well maybe RC 3D too)
By just plugging in a random rpm number to go along with that prop [let's say 14000 rpm]...the result is 10 pounds of thrust...!
The resulting speed would be 55 mph...which gives this hypothetical plane a 5 second per lap pace...so I don't think this WAG is too far off.
I think all the "Top flyers" are going electric now. The low pitch props are the normal to slow them down when heading down hill and keep the engine in it's power band.