http://www.popsci.com/popsci/aviatio...563899,00.html

Interesting reading in the 01/2004 Popular Science and the approach to fuel
consumption.

Frank Whiteley

"John Mason" wrote in message
...
The advantage of the lightweight jet engine is totally eclipsed by the
fuel
consumption problem.

A self launcher engine and prop and fuel tanks weighs 55-60kg with full
fuel
tanks. They are already heavy enough and it would be better to go lighter
not heavier.

A pair of jet engines will weigh only 7kg but the fuel with tanks will be
about 95kg and so at 103kg is nearly double the weight surcharge,
furthermore as I implied before there is a big problem in finding enough
room to store 120lts. There may also be a weight and balance issue but if
the fuel were stored in the wing tanks instead of water ballast that would
be less of a problem but you would have little room left or weight reserve
for water then. You could treat the fuel as ballast and dump the fuel if
you chose to, it is pretty cheap stuff, cheaper than many brands of
mineral
water.

If there existed a model fanjet engine and if it were to use say less than
half the fuel, a jet engine would begin to look like a good option.

"Peter Seddon" wrote in message
...
To give the same duration the jet will need a very large and
heavy-when-full 120lt tank.

Yes but what about the weight saving over the mechanics of the petrol
engine/prop etc.?

Peter S
DLA