Airtech,
Have you firsthand experienced a Evolution 45 turn a 24x10 prop at 6200? And with what a stock muffler? Tuned Pipe?
Horizon's specs show the engine to really be a 43cc engine.
They also state the benchmark prop as a 23x8 Mejzlik at 6100...
Zinger's are notoriously "light pullers' as are TopFlight's
As someone else mentioned somewhere... they make real good paint stirrers.
Even then I'll be the first to state I don't believe the 45 can spin a 24x10 prop at 6200... and it if CAN because it's a wimpy prop, then a 50 CC engine can spin the SAME EXACT PROP faster... considerably.
To compare apples to apples plug in a 23x8 Menz at 7100 that's my verifiable rpms's on a DA-50... or
Sure I could spin a 24x10 Zinger... and considerably faster than the 45 will (whatever that real number is)... but why? it's not an ideal prop for 3D OR IMAC on a 50cc or less engine.
The 45 weighs within tenths of an oz of a DA50... and unless they have some "magic" that no other engine has cannot put out the same power.
When they also cost the same and the 50 has over 16% more cc's of power at the same weight... well...
It's been covered about the ThrustHP figures... and while certainly a nice benchmark for comparing engines spinning the same prop, actual thrust tends to be perhaps 30% less than "calc'd"
ORIGINAL: AirTech
One of the most widely used software to calculate thrust and horsepower output is ThrustHP. This freeware is available at [link=http://freespace.virgin.net/barry.hobson/software/goodies.html]Model Goodies[/link]. In the case of an engine (i.e. MVVS 45GX) turning a 24-10 at 6200 RPM a Zinger wood prop should produce 5.648 HP and 36.08 Lb. of static thrust. The same engine with a MenzS will produce the same power, and 37.19 Lb. of static thrust. In comparison the new ZDZ40 RV-L will need to turn a (much smaller) 20-10 MenzS at 7400 RPM to produce 4.631 HP and 25.54 Lb of thrust. On the other hand a BME 50cc Single spinning a 21-8 MenzS will need to turn at least 8100 RPM !!! to produce 5.906 HP and 37.19 Lb of static thrust.