best self-launcher propulsion system?

On Jan 10, 4:48*pm, key wrote:
I am curious what group members with experience with self-launchers
regard as the best propulsion system (currently) in terms of in-flight
restart reliability, maintenance, safety, and other operational
factors (e.g., vibration). *Of course the electric Antares might win
on all counts except for range, but it is out of my price league.

thanks,

Key

Another vote for DG800B
restart reliability - it has always started for me. Very predictable
starting behavior.

maintenance - usually something to address each annual. SLG are
complicated things and you have to know the machine and what to look
for. In the case of the DG it is a good one for those who have dealt
with engines before. just my 2 cents.

safety - safe.. sure. Meaning, take good care of it and it will take
care of you. Dont take care of it and dont follow good MG
practices(see books on subject like Eric's/Pete Williams) and you are
likely to get in trouble.

operational factors - great self launch climb performance even loaded
with water at high altitude. Watch out on high crosswind takeoffs but
I think that is true of other similarly configured SLGs.

On Thursday, January 12, 2012 5:24:20 PM UTC-5, db_sonic wrote:
... Watch out on high crosswind takeoffs but
I think that is true of other similarly configured SLGs.

Nope, Antares has no springs in tailwheel linkage and
heavy tail weight - this keeps tail firmly on ground
with very positive steering. Gliders with light tail
weight can be VERY challenging in cross-wind, and you
will need to advance throttle very slowly lest you
lift the tail and immediately turn into wind (and
thereby careen off the runway). Those gliders do keep
the repair shops busy tho...

IIRC 26 has heavy tail but does have springs; not
sure about xwind performance ?

Hope that helps,
Best Regards, Dave "YO electric"

On 1/12/2012 3:28 PM, Dave Nadler wrote:
On Thursday, January 12, 2012 5:24:20 PM UTC-5, db_sonic wrote:
... Watch out on high crosswind takeoffs but
I think that is true of other similarly configured SLGs.

Nope, Antares has no springs in tailwheel linkage and
heavy tail weight - this keeps tail firmly on ground
with very positive steering. Gliders with light tail
weight can be VERY challenging in cross-wind, and you
will need to advance throttle very slowly lest you
lift the tail and immediately turn into wind (and
thereby careen off the runway). Those gliders do keep
the repair shops busy tho...

IIRC 26 has heavy tail but does have springs; not
sure about xwind performance ?

The 26 does have a heavy tail, which provides very good directional
control with a cross-wind, even with plenty of throttle. The later
versions have a propeller with more static thrust, so a bit more care is
required than with the earlier ones like mine. The gain is a shorter
takeoff run and a better climb rate.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

After three years ofoperatinmg a PIK 20E, I have some
varied experience to relate.

Pro:
the wing develops the tunnel tested Cl; with gap covers
and winglets, the stall is under 40 kts, thermaling in smooth air
at 45kts, and sink less than 1.3 kts at 50kts. ( vs ASW 24)
Takeoff less than 200yds and climb about 5kts at 10/1 .
Respect the book crosswind limit.
Noise and vibration are fairly bad but the engine can be 80%
retracted right after shutdown allowing immediate climb.
The flywheel detent and claw with doors open, allow prop
alignment without a mirror or brake. ( this is a retrofit item)
Handling is very good with the usual caveats about rough thermals
, bugs and RAIN. If you really provoke a spin, it goes vertical
before recovery at 80-90 kts.
Air starts have been reliable except for an early case where the
door control jammed due to a rod misaligment. Forced outlanding
in the worst field of my 50yr career was too exciting.

Con.
the 16 deg flap hardly decreases the stall speed and degrades
the aileron response to poor.
The engine has provided a lot of entertainment and
occupational therapy.
Several incidents of power loss or failure.
Causes: 2 yr old fuel hose wentsoggy and internally restricted.
Old (original ?) ignition wire corroded at the coil.
Oil on the plug insulator caused short.
Blocked breather on fuel cap ( insect mud inside, invisible)
Stuck choke, choked it at full throttle!
Mikuni pump diaphragm aging ; low fuel pressure.

Ground starting a bit uncertain; if you flood it, the plugs have to
be removed.
Tailwheel steering inadequate; taxiing wing down impossible.
Corrected by installing extra coupling spring, rudder to castor.

Failures and defects.
Tank filler neck seperated from tank
Prop shaft locking nut , very important AD.
Cable retracting spring broke (corrosion )
Fuel leak at carb inlet; intractable. carb removal needed.

If you rely on an AME to fix things, you will need a deep pocket!

John F
PS:
I am now happy with my PIK 20E!

On Jan 12, 2:07*pm, key wrote:
Guys

..........Unfortunately i am too tall (6'4") for
the Silent electric (assuming the cockpit is the same size as the
Silent petrol).

Key

Hi Key,
did you sit in a silent cockpit?
6'4" or 193 centimeter........... too tall...........
MAYBE YES, MAYBE NOT:
depends on the size of torso vs legs,
I've seen a pilot 187 cm tall trying the cockpit of pure silent and
fitting well with rudder
pedals in the before the last notch adjustable position.
Happy Landings..........

On Jan 12, 3:28*pm, Dave Nadler wrote:
On Thursday, January 12, 2012 5:24:20 PM UTC-5, db_sonic wrote:
... Watch out on high crosswind takeoffs but
I think that is true of other similarly configured SLGs.

Nope, Antares has no springs in tailwheel linkage and
heavy tail weight - this keeps tail firmly on ground
with very positive steering. Gliders with light tail
weight can be VERY challenging in cross-wind, and you
will need to advance throttle very slowly lest you
lift the tail and immediately turn into wind (and
thereby careen off the runway). Those gliders do keep
the repair shops busy tho...

IIRC 26 has heavy tail but does have springs; not
sure about xwind performance ?

Hope that helps,
Bmest Regards, Dave "YO electric"

mm, sort of. Tail is light, yes(which is good for moving the ship
manually) but springs are not really the issue.
The power is so much it lifts the tail if you jam the throttle and
then the subsequent wind vaning but only if the crosswind is around
10kts or more.
Seems to be more of any issue at higher altitudes and much less near
sea level.
But I dont think I need to advance the throttle any slower than I
would in a 172.
Anyways, the reason I said other gliders is because it was F8 that
taught me how to improve my technique(for which I am grateful) based
on his experiences.