Hi Chris
These are close numbers for you
you are making very close to 50 in ounces of torque,
and right at 1\4 HP ,
this assuming level flight and the normal RPM gain from the motor unloading
HP and torque will vary some what (assuming you numbers stay the same) depending on which 11 inch brand of prop you have on, what the pitch really is, what nitro percent, day condition, needle setting , etc.
Regards
Randy
Randy,
Thanks for that. I knew my question was going to head into deep water, just wasn't sure how deep.
What brought this on is the introduction of a P40 class at one of the local competitions I regularly enter. I've been flying a Tom Warden Trophy Trainer for some time now, but with a 45 in the nose. My dilemma was whether the model would fly OK with a 40 as my model production rate has hit fractional models per annum for now and there was no way I would complete a model in time.
Peak output of the 45 is rated at 1.2 hp.
My replacement 40 has a peak output of 1.1 HP, but of course I've no idea where this power occurs in the torque/rpm curve of either motor.
What stumped me at first was that with the same prop, the take off RPM was lower with the smaller motor, but my lap times were the same, and the only difference I could discern in the performance was that the smaller motor was more critical on tank alignment, what was OK for the 45 was clearly not good enough for the 40.
From this comparison I can only assume the smaller motor is leaning out more in the air as tank/prop/lap time are the same and ergo both motors are producing the same amount of power, as the lap time seems to me to be determined by rpm and pitch, given that we're talking about the same propeller/airframe here.
I also have a Nobler with the same power plant and did a 1:1 swap of 45 for 40. Identical behaviour, so my experience with Trophy Trainer was no fluke.
I'm unlikely to ever be world champion, but this little experiment has made me re-evaluate what I thought I knew about CL stunt.
More to the point, it has made me question the choice of power plant for my current build and planned next build, I'm thinking I've been going well overboard and what I was planning to fit 60s to might fly just as well or even better (since they'd be lighter) with, say, my 45s.
Of course, the other side of the coin here is that my recent flying has been in stunt heaven conditions, whereas at least 2 of the competitions I plan to attend will be in much less favourable conditions, if only just because of their locations.
Chris