On Nov 2, 2:36*pm, Martin Gregorie
wrote:
On Sun, 01 Nov 2009 19:14:52 -0800, Darryl Ramm wrote:
The electrics have the benefit of not having to worry about mixture
settings at altitude, somethign many self launchers or sustainers
cannot deal with except by adjustment on the ground. I hope the people
making this produce some performance data for high density altitudes
(~10,000'). Around mountains 'out-west' most sustainers are next to
useless.

Judging from the performance of free flight models at Denver vs the same
models at Sacramento, the FES should be better than an IC sustainer. Its
noticable that power models lose performance big-time at Denver while
rubber powered models are much less affected. Now doubt this is due to
the way an IC engine loses power with altitude while electric or rubber
motors are unaffected.

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

Really good point - I believe it's true that most of the power loss
with altitude is from loss of power produced by the engine, not prop
efficiency. Electric motors don't have this power loss because they
don't depend on combustion.

9B