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Old February 16th 06, 03:01 PM posted to rec.aviation.soaring
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Default Seeking Self-Launching Intelligence

20,000 Euro? Ouch! That should have paid for a new motor.

To add a bit more to this, last year I checked the propeller and engine
balance (vibration spectral analysis) on another motorglider at Minden, with
an Aces 2020 prop balancer.

Keeping in mind that less than .05 ips is considered smooth, while more than
..5 is quite rough, at the frequency of the prop, I measured .24 ips. At the
engine frequency, it was just over .7 ips. Balancing the prop, which we
didn't have time to do, would have resulted in little discernable reduction
in perceived vibration levels.

My ASH26E measures less than .03 ips. It did require prop balance weights to
get it that smooth. As delivered, it was .24 ips. Probably an anomaly, as
two other 26's I've looked at showed less than .05 ips (smooth)
out-of-the-box.

all the best,

bumper
Minden, NV
"Graeme Cant" wrote in message
...
bumper wrote:

Also consider that many of the "small" problems that occur, with the Solo
2-stroke powered ships, are vibration related. These problems don't often
result in AD's, they just get quietly fixed - well, except for cussing
which always helps speed repairs. Such problems include broken wiring
connections, sheared bolts, broken brackets etc.


My experience is that that is very true. The Solo isn't the only problem.
All 2 stroke engines seem to be the same. As you say, not all result in
ADs - but many do. A number of the ADs on the DG400s, 500s, 800s relate
to things like staking ring gears and fuel line fractures - all vibration
driven.

Two strokes are inherently bad for vibration and the only things in their
favour are the smaller number of moving parts (than a 4-stroke) and the
power/weight ratio. The engine's are reliable but the accessories and
mountings are another story.

The Wankel engine, on the other hand, is by nature turbine smooth.


OTOH, the last bill I heard of for a Wankel that needed internal work was
20,000 Euro plus an eight week round trip from Oz.

Graeme Cant


bumper
ASH26E
Minden, NV
"Eric Greenwell" wrote in message
...

Thatcher Smith wrote:


I am considering purchasing a self-launcer, likely in Ventus, ASH26, or
DG808 guise and would like to know:

-do those of you who operate these or similar machines ever lose
soaring days due to malfunctions in the power system?

Yes, though the losses can be reduced by taking a tow. In my 11 years of
owning my ASH 26 E, I've only lost a couple days, but that's partly that
depends on when and what problem occurs. Most of the problems were in the
first 3 years; the last 8 have been uneventful.

The AD history of a particular model will give you an idea of how much it
might have lost over the years; however, many ADs don't immediately stop
a glider from flying, but give it some time to comply. The repairs can
often be scheduled for minimum impact.


-are there large price and/or operating cost differentials between
these three?

No, they are very similar in operating cost and price; however, the Solo
2 stroke engine powered Ventus and DG 808 have had more trouble in the
last few years than the Wankel rotary (by Diamond Aircraft) engine
powered ASH 26 E.


-are there reliaibility differences?

In the last few years, yes, but perhaps the latest fixes for the Solo
engine should close the gap with the Diamond Wankel engine. The future
lies ahead of us, of course, and surprises may be waiting, as owners of
the previous generation of motorgliders will be happy to point out.


-are there build quality/longevity differences?

Glider or engine?


-is it difficult to find informed persons to service the power system?

I can't speak for the Solo crowd, but it is to some extent for the
Diamond engine. Even so, anything that does not involve the internals of
the engine can be handled by a competent mechanic (or appropriately
supervised owner); if the problem is internal, it has to go back to the
factory. On the West Coast, Rex Mayes of Williams Soaring can handle
everything but the internals, and likely High Country Soaring in Minden
may also be able to. I'm sure there are others on the East Coast and
elsewhere.

What makes this acceptable to the ASH owners is an internal problem is
quite rare, and the occasional external problem is generally easy to deal
with.

For more resources, visit www.motorglider.org, the website of the
Auxiliary-powered Sailplane Association (ASA). There are lists of owners
groups you can visit, and if you become an ASA member, you can post
questions on the ASA newsgroup. And be sure to download "A Guide to
Self-launching Sailplane Operation" from the site, which covers the
things the pilot should know for safe and effective operation.

--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"