Re: Re: My new pennyplane

From: John Barker <john.barker783_at_ntlworld.com>
Date: Thu, 24 May 2012 17:23:08 +0100

Richard

I am not an Indoor expert but I have flown an LPP under a ceiling similar to yours so the following may be of some use.

We fly our LPP competitions with 0.75g of rubber and a 0.75g spacer. I have notes of using motors of 0.054 and 0.056 g/inch which will be a strip width of just over 0.08" as compared to your 3/32 (0.094"). Best flights were wound to about 1 inch.oz of torque (about 850 turns) and backed off to a launch torque of 0.7 inch.oz. The only 'turns left' figure I recorded was 45. Best flights were about 4.5 minutes.

Your aeroplane looks very good and well made but I recommend that you have a check on the propeller dimensions. My propeller is 12" diameter with a blade angle of 40 degrees at the three quarter radius. This gives a nominal P/D ratio of 1.98.

Your model is certainly flying very smoothly but to my, not very expert, eye too smoothly for a low ceiling. My model flies the early circuits much nearer the stall, nose well up, flying very slowly and thus stalling the propeller and reducing rpm and not climbing very much. As the torque reduces the nose drops and the climb rate increases.

Don't take my figures as 'best practice' but they are at least something to compare to your own.

John
Received on Thu May 24 2012 - 09:58:19 CEST