best self-launcher propulsion system?

Hello Key,

While you are stirring the pot, I may as well join in.

The best self launching glider or the best self launcher propulsions
system? They're not necessarily the same thing. Some gliders are
fairly well sorted as self launchers and may not be the best glider
but may be the best self launching glider. Some propulsion systems may
be brilliant as an idea but not completely suited to the application…
at least not with the current state of the art.

And what sort of flying do you want to do? Self launch and the
occasional single or double motor run retrieve or is the main purpose
of the glider things like long distance safaris where longer range is
required and where jet fuel or battery charging facilities may not be
available at the remote airfield?

Does the region you fly in have big sink? My SLG does 800 fpm or
better climbing under motor and I have seen zero on the dial for a
minute or two when doing an in-air restart. Bear that in mind when
considering the possible height gain on an electric powered glider.
You may lose 50% of your motor run before you actually gain any
height.

How long will you keep the glider and how much money do you expect to
lose when reselling the glider? 2 stroke self launchers have held
their price remarkably well but I doubt that you'd get the same thing
with electric powered gliders, close to a battery replacement time.
Gliders like the PIK 20E and the DG-400 are 25 and more years old and
still going strong. I sold my DG-400 unseen within 3 days of
advertising it and had enquiries from Patagonia to Austria. The buyer
said, 3 months later, that the glider was "everything he dreamed it
would be".

I've seen one jet self-launcher take off and it was frankly
terrifying… both in terms of the noise and the lack of height gained.
And the massive fuel use.

Water cooled two strokes have been around for 80 years or more and the
technology is very well understood. Yes, vibration is a bit of a
problem but it's hardly a disaster. Jet and electric power plants have
not been around very long and the technology is changing every year…
or faster. Yes, the batteries may last 1000 cycles (I have NEVER known
any battery actually do that or even vaguely meet the manufacturer's
promised lifetime) but are the manufacturers of the glider going to re-
certify items like new battery technology, new speed controllers and
new electric motors every few years to replace the obsolete versions?
They don't have a great history in doing that with other items!

Regrettably, in my opinion right now, if you are not a millionaire and
you want to fly some distance away from your home strip, the best
choice is petrol or petrol.

The ASH owners are fairly vocal on this list but you don't hear much
from DG owners, so here's a bit. I have owned 2 DG gliders and believe
that they are the best sorted SLG out there. I think DG take self
launching gliders very seriously and it shows in almost everything
from the brilliant DEI-NT to the steering tailwheel, large wingtip
wheels, taxiing wingtip dolly etc. etc. as well as progressive safety
features like the Piggott hook and NOAH.

Certainly, in terms of serious problems, the DGs in our region do
very well compared with others which have a reputation for self
combusting is significant numbers!

I agree with GC in that you cannot have too much power and under
powered SLGs are terrifying, both inside and outside the cockpit. The
climb rate on take off in my glider is very impressive… I have never
watched but whenever I land, people come over and talk about it. Only
last week, two other pilots, one of whom has an Arcus on order, stated
that in his opinion, "DG make the best SLGs… period". The other wanted
to buy a share in the glider. The DG 808 is the glider of choice in
places like the Alps where climb rate and reliable engine starting
really counts.

Look at the sales figures for SLGs over the last 25 years. One
manufacturer has sold over 50% more single-seaters than the others… it
might be close to double the amount of the nearest competitor.

Like Bumper, I appreciate things mechanical… it's my job… and I have
to say that I don't see any of the current IC SLGs being perfect and
in many ways you pays your money and you takes your choice of the type
of problems you want to run into… vibration, fire, breaking belts due
to backfiring, breaking belts due to bending incorrectly when stowing
the engine… there's quite a laundry list. However, the benefits appear
to largely outweigh the drawbacks. And I bought two DGs.

You can find a fairly full run down of the options he

http://www.keepitsoaring.com/LKSC/Do...ember_2010.pdf

D