AviationBanter - View Single Post

**Charles Vincent**

wrote:
In rec.aviation.piloting Tim Ward wrote:

wrote in message
...

The advantage from the electric engine at cruise is that it uses zero
energy.

Snippage
--
Jim Pennino

Remove .spam.sux to reply.

You want to support this, somehow?

Tim Ward

At cruise the electric motor is turned off.

The only energy used is some slight bearing friction.

The electric motor is only turned on when more power than the gas
engine can provide is needed.

To carry more weight at the same speed and altitude takes more power, so
you have to account for the energy expended kiting you deadweight
electric takeoff system around the sky as well. Sizing an engine for
cruise has been done, if only backwards. Think JATO. Most JATO's are
actually RATO (rocket assisted takeoff). I expect RATO would beat an
electric system based on energy density and the fact that when it is
done you have reduced your weight by the fuel. I also suspect for a
given amount of thrust the rocket will be lighter than an electric motor
and associated clutches and gearing. In my opinion, at this point in
time it is just as practical for a homebuilt as well as in not.

Charles