Antares 18S Maiden Flight

At 11:30 06 June 2006, Ruud wrote:
On Mon, 05 Jun 2006 09:12:12 -0600, Shawn
wrote:

Andor Holtsmark wrote:

Why are these two stroke engines so notoriously unreliable?

-I just want to clarify that I did not ask this question.
I asked about how many self sustainers used regularily
hour after hour suffers from engine trouble. I hope
the difference is clear.
I am not trying to imply that this must happen, I am
curious about what the experiences are.

Andor

My DG808B self-launcher uses 4 sealed batteries and
they all can be replaced for less than $80 which I
believe is typical. The batteries are cheap enough
that I replace them every two years regardless of condition.
There is no gas powered glider that I know of with
a $1000 battery but perhaps an electric self-launcher
battery could be that expensive.
Reliability and maintenance on any powered glider is
going to be significantly more of an issue than a pure
glider. It isn't like buying a Chevrolet where the
various systems have been refined over a long period
of time. The fuel/electrical systems used today are
pretty crude compared to modern automotive design but
given enough attention and preventive maintenance they
perform pretty well. Routine operation is a very good
idea regardless if it’s a self-launcher or sustainer.
With the exception of one loss of electrical power
mine has never failed to start or in flight after 325
frame and 25 engine hours. In that same period I have
experienced 4 rope breaks on tow so the self-launcher
reliability looks pretty good to me.


At 17:48 06 June 2006, Charles Yeates wrote:
I was told the engine start battery replacement cost
$1,000

Eric Greenwell wrote:


AT Parowan last June, one supper conversation with
three owners of
powered single seaters detailed two propeller problems
(manufacturer
took a season to sort out) and one battery failure
(expensive) --
unusual, I suppose. But not engine problems, eh?


Were these all two stroke engines? And I'm very curious
how a battery
failure could be expensive, given the low cost of
batteries.

Maybe the high figure is what he told his wife??

Gary Evans wrote:
My DG808B self-launcher uses 4 sealed batteries and
they all can be replaced for less than $80 which I
believe is typical. The batteries are cheap enough
that I replace them every two years regardless of condition.
There is no gas powered glider that I know of with
a $1000 battery but perhaps an electric self-launcher
battery could be that expensive.
Reliability and maintenance on any powered glider is
going to be significantly more of an issue than a pure
glider. It isn't like buying a Chevrolet where the
various systems have been refined over a long period
of time. The fuel/electrical systems used today are
pretty crude compared to modern automotive design but
given enough attention and preventive maintenance they
perform pretty well. Routine operation is a very good
idea regardless if it’s a self-launcher or sustainer.
With the exception of one loss of electrical power
mine has never failed to start or in flight after 325
frame and 25 engine hours. In that same period I have
experienced 4 rope breaks on tow so the self-launcher
reliability looks pretty good to me.

Gary Evans schrieb:

...
With the exception of one loss of electrical power
mine has never failed to start or in flight after 325
frame and 25 engine hours. In that same period I have
experienced 4 rope breaks on tow ...



Good heavens!!!
I strongly suggest you start using different ropes!

Marcel

At 16:18 06 June 2006, Shawn wrote:

Seems like a preflight run-up of the engine would reveal/mitigate
many
starting problems in flight.


My thought exactly.

There have been some comments here that sustainers
generally are not run up prior to flights (presumably
including flights where use of the engine is a distinct
possibility) AND that periods of inactivity significantly
up the odds of the engine failing to start.

If both of these statements are true it seems that
flying a sustainer-equipped sailplane cross-country
without a preflight engine runup is a bit of a roll
of the dice. It also raises in my mind two somewhat
related questions:

1) Is there a good reason why one shouldn't do a runup
prior to every (cross-country) flight?

2) Do many pilots flying sustainer-equipped sailplanes
presume that the engine is unlikely to start and not
care, do they presume that the engine IS likely to
start (correctly or incorrectly), or do they believe
a preflight runup doesn't help the odds anyway.

Thoughts?

9B

Andy Blackburn wrote:
At 16:18 06 June 2006, Shawn wrote:

Seems like a preflight run-up of the engine would reveal/mitigate
many
starting problems in flight.


My thought exactly.

There have been some comments here that sustainers
generally are not run up prior to flights (presumably
including flights where use of the engine is a distinct
possibility) AND that periods of inactivity significantly
up the odds of the engine failing to start.

If both of these statements are true it seems that
flying a sustainer-equipped sailplane cross-country
without a preflight engine runup is a bit of a roll
of the dice. It also raises in my mind two somewhat
related questions:

1) Is there a good reason why one shouldn't do a runup
prior to every (cross-country) flight?

2) Do many pilots flying sustainer-equipped sailplanes
presume that the engine is unlikely to start and not
care, do they presume that the engine IS likely to
start (correctly or incorrectly), or do they believe
a preflight runup doesn't help the odds anyway.

Besides the issue of the engine readiness, there is the issue of pilot
readiness: if the pilot hasn't started the engine in the air recently,
isn't he more likely to bungle the start when he getting low and under
pressure? Even better than a preflight, on-the-ground start, would be to
do it after releasing from the launch. You could even take lower
aerotow, and save a bunch on the tow fee.

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

Eric Greenwell - Washington State, USA

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

Andy Blackburn schrieb:

1) Is there a good reason why one shouldn't do a runup
prior to every (cross-country) flight?

Yes. It has no starter. (And, btw: Even if it had one, the simple fact
that it starts *now* doesn't mean that it will start *then*.)

2) Do many pilots flying sustainer-equipped sailplanes
presume that the engine is unlikely to start and not
care,

Yes and no. Yes, flying a sustainer we *always* presume that the engine
is unlikely to start. And no, we actually care. Thats why we never rely
on a ststainer but only start the engine over a landable field.

Stefan

Stefan wrote:
Andy Blackburn schrieb:

1) Is there a good reason why one shouldn't do a runup
prior to every (cross-country) flight?


Yes. It has no starter. (And, btw: Even if it had one, the simple fact
that it starts *now* doesn't mean that it will start *then*.)

I know some or all start in the air by windmilling. Is there a pull
string starter or the ability to hand-prop on the ground?

Your statement about "the simple fact that it starts *now* doesn't mean
that it will start *then*" is unassailable, however the odds may
improve. If it *doesn't* start now would be a good reason to not expect
it to start in the air ;-)

Shawn

At 16:18 06 June 2006, Shawn wrote:

Seems like a preflight run-up of the engine would reveal/mitigate
many
starting problems in flight.


My thought exactly.

There have been some comments here that sustainers
generally are not run up prior to flights (presumably
including flights where use of the engine is a distinct
possibility) AND that periods of inactivity significantly
up the odds of the engine failing to start.

If both of these statements are true it seems that
flying a sustainer-equipped sailplane cross-country
without a preflight engine runup is a bit of a roll
of the dice. It also raises in my mind two somewhat
related questions:

1) Is there a good reason why one shouldn't do a runup
prior to every (cross-country) flight?

2) Do many pilots flying sustainer-equipped sailplanes
presume that the engine is unlikely to start and not
care, do they presume that the engine IS likely to
start (correctly or incorrectly), or do they believe
a preflight runup doesn't help the odds anyway.

Thoughts?

9B

I don't believe that there is anything wrong or suspect
with two stroke engines. You do have to be careful
with them, here are the things that I've learned from
motorbikes and glider turbos

Use the best sparkplugs you can get to avoid two stroke
whiskering, try platinum or exotic equivalent

Take care of your plugs

Do a DI of your engine before flight, are all the bits
there, eg, the HT leads are ON

Take scrupulous care with your fuel/2 stroke mixing

Prime your engine before takeoff

Start your engine before starting task, 2nd starts
are always much quicker for some reason

Remember the sequence fuel on, erect, ignition, TE
change over, push prime, pull decomp speed up and release.

Sounds dificult but it isn't with practice - this on
a Ventus c so its a bit old tech compared to ASW 28
and ASG 29s or DG1000s.

After a couple of months layoff the engine is much
slower to start and needs determined effort to get
it going. I presume that it needs to blow oil out of
the crankcase and cylinders.

John