RE: CMP BF109F BUILDING THREAD
The HP number you guy’s are bouncing around are break horse power numbers. I’ve never seen it done but as I understand it they rev the Pix out of the engine while free wheeling. Then apply a break until the engine dies that gives them to measure the energy in the motor. Problem is that a 2cycle will rev a lot higher than a four stroke unloaded and that is why the numbers are so squed.
If you want accurate number here is the formula for Hp:
((RPM x RPM x RPM) x (D x D x D x D) x P)/140000000000000000
(Rpm cubed)
D=diameter
(D to the fourth power)
P= pitch
Next time out get a RPM reading and find out what your favorite engine is really putting out in Hp. Some examples of my engines:
Super Tigre GS-45 12.8k 10x8 1.2hp
Rossi40 14.5 10x6 1.3hp
Super Tigre S-90 9.6k 15x6 1.48hp
OS 1.2 4C 8.75k 15x8 1.94hp
This does not account for torque, 4c have a big advantage there that 2c will never ketch them on. The best way to remember the difference between torque and Hp is. Hp keeps your car going 75mph on the highway. Torque is what got it there.
Joe