Bill Daniels wrote:


I don't disagree about motorgliders but there will always be a lot of pure
gliders around that need launching. Diesels will produce the same power on
roughly 1/3 less fuel and that fuel could be un-taxed agri-diesel in the
case of a warm weather glider tug. That would be a large but not
overwhelming savings. If diesels get as popular as most aviation experts
suggest, the availability of avgas and spark ignition engine parts and
repair may eventually be a greater concern.

A typical 180 HP Lycoming O-360 will burn $60,000 worth of avgas to get it
to a 2000 Hr TBO. A 260 HP Lyc O-540 will burn close to $100,000 worth of
avgas in 2000 hours. Engine overhauls are also a big cost but less per hour
than fuel. Any way you look at it, a tow plane is a black hole sucking in
money.

If you really want to save fuel, think winch launch. That takes about 1/2
liter of diesel to launch a typical glider. That could easily be vegetable
oil. If you are lucky enough to be able to use an electric winch, a launch
will use about 1KW Hr. of energy at about $.05. Add to the fuel savings the
fact that you don't have to deal with the FAA trying to get a Tost hook
installed on a Pawnee.

Oh now, you had to rub that in didn't you.
;-)

Shawn