Self Launch vs Engine-less
Eagle Data
self-launching glider?
Of course there is a large price penalty for a new self launch vs the
engine-less version. Besides the money what else should a glider pilot
consider? If money were not the issue, what would you buy and why?
JD
Eagle Data
newsgroup - JD:
>JD: The self-launch feature buys you tows during the week when the club
is not operating. If you live near a commercial operation, you don't need
a self-launcher for that reason. The engine is a retrieve crew. If you
have a dedicated familymember who will retrieve, you don't need the motor.
The engine will get you up from ANY airport where you wish to fly.
Caution! The cockpit of a self-launch sailplane can be a very busy
place!
I suggest an absolute minimum of 500 hours in high performance sailplanes
with 2 or 3 diamonds should be achieved before considering buying a
self-launcher. And 1000 hours would IMHO be better. At least 10
out-landings and/or an outlanding course is an additional requirement, I
think.
More discussion would be welcome. :-) Ventus cM NL Dave
Ian W Strachan
eagl...@aol.com "Eagle Data" writes:
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> From: eagl...@aol.com (Eagle Data)
> Newsgroups: rec.aviation.soaring
> Subject: Re: Self Launch vs Engine-less
> Date: 28 Oct 1995 13:12:57 -0400
> Organization: America Online, Inc. (1-800-827-6364)
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From Ian Strachan, Lasham Gliding centre, UK.
I have been an enthusiast for high performance motor gliders since I first
flew a Schleicher K-14 in 1968, and have flown nearly 20 types of MGs from
the early Scheibe SF 27M which set the basic engineering of the pylon, to
my present Nimbus 3DM self launcher. I therefore have a contribution
to this thread on MGs ......
> The self-launch feature buys you tows during the week when the club
> is not operating.
Absolutely. You buy convenience and sometimes soaring when others can't.
> If you live near a commercial operation, you don't need
> a self-launcher for that reason. The engine is a retrieve crew. If you
> have a dedicated familymember who will retrieve, you don't need the motor.
If you don't mind landing in fields with all the hassle. I did not mind
field landings at one time but after about 100 of them they became a bore.
I am now a very busy guy who likes SOARING, not sitting in a field fending
off a herd of cows and finding out that my retrieve car keys are in my
trouser pocket and not back at the club ....
> The engine will get you up from ANY airport where you wish to fly.
Not true, most High Performance MGs have a limited taxying capability in
a crosswind, and Schempp-Hirth has yet to be convinced that ANY taxying
capability is needed at all, not for want of trying on my part, see my
write-up on the Nimbus 4DM in the Brit magazine `Sailplane and Gliding'.
Generally, it is only the much lower performance `Touring/Training
Motor Gliders' (TMGs) which can operate almost like a light aircraft.
Also, remember the range of self sustaining MGs such as Schempp's `Turbo'
series. Restarting a Turbo is very straightforward and the cockpit
panel is very simple, there is not even a throttle .... The self-sustainer
is an avenue worth serious consideration if you have regular launching
available but like me do not want to waste time sitting in fields.
> The cockpit of a self-launch sailplane can be a very busy place!
Yes, and the usual common-sense rules apply on a humble approach to the beast
that you are flying, constant practise of air re-starts, good knowledge
of field landing techniques, etc.
> I suggest an absolute minimum of 500 hours in high performance sailplanes
> with 2 or 3 diamonds should be achieved before considering buying a
> self-launcher. And 1000 hours would IMHO be better.
This is really over the top, I believe. And 1000 hours is nonsense, what
are you trying to preach? That MGs are too dangerous (or perhaps too
desirable) for normal human beings? The key points are common sense
(airmanship), constant practise in air restarting, and decisions to air
start taken 1. in time and not in panic, and, 2. with a landable field
always selected in case of any problem with the motor. I would say, get your
silver C in a straight glider, take a good field landing course, evaluate
your potential MG thoroughly before you buy it, and operate it cautiously
for the first season (and perhaps all seasons!), because, as the Tiger Club
motto has it "all aircraft bite fools". Don't be a fool .... If in
doubt, buy a self-sustainer such as a Schempp `Turbo'.
> At least 10
> out-landings and/or an outlanding course is an additional requirement, I
> think.
Absolutely, strongly agree. Any MG soaring pilot MUST have sufficent
background of real field landings so that he or she can select a good field
and fly a circuit pattern if an air re-start becomes needed. For an already
experienced glider pilot this is no problem but for a newbie to gliding,
this is the main difficulty in going early to an MG.
The other problem for newbies is their lack of soaring experience and a
tendency to use the motor too much instead of gritting the teeth and
soaring out of trouble.
But like all technical progress there are awkward areas and this should
not put off a guy who is keen on soaring rather than using an MG as
a powered aircraft.
One suggestion would be to enter a couple of glider competitions with
a straight glider or with the MG but under rules where you are not allowed
to use the engine to prevent a field landing. You should have a dedicated
crew and will quickly pick up experience in soaring out of awkward situations
and possibly some real field landings. Then your later MG flying will be so
much better based. Comps are great fun, anyway, and you always learn a lot
from others. Strongly recommended.
> More discussion would be welcome. :-) Ventus cM NL Dave
You got it!
Best wishes and good soaring without using the motor ...
--
Ian Strachan
PS Dave, can you taxy the Ventus CM ?
David H Noyes
Ian W Strachan <i...@ukiws.demon.co.uk> wrote:
>> Subject: Re: Self Launch vs Engine-less
>> Date: 28 Oct 1995 13:12:57 -0400
>> Organization: America Online, Inc. (1-800-827-6364)
>> Lines: 26
>> Sender: ro...@newsbf02.news.aol.com
>> Message-ID: <46toap$1...@newsbf02.news.aol.com>
>> NNTP-Posting-Host: newsbf02.mail.aol.com
>> X-Newsreader: AOL Offline Reader
>>
>
>From Ian Strachan, Lasham Gliding centre, UK.
>
Sorry, I should have said, "Any airport with sufficient runway length for
the density altitude."
>Not true, most High Performance MGs have a limited taxying capability in
>a crosswind, and Schempp-Hirth has yet to be convinced that ANY taxying
>capability is needed at all, not for want of trying on my part, see my
>.... the usual common-sense rules apply on a humble approach to the beast
>that you are flying, constant practise of air re-starts, good knowledge
>of field landing techniques, etc.
>
Hear! Hear!
> And 1000 hours is nonsense, what are you trying to preach?
> The key points are common sense (airmanship), constant practise in air
restarting, and decisions to air start taken
>1. in time and not in panic, and, 2. with a landable field
>always selected in case of any problem with the motor. I would say, get your
>silver C in a straight glider, take a good field landing course,........
Good instruction can substiute for time.....and vice versa if you survive.
>PS Dave, can you taxy the Ventus CM ?
Yes, but strong cross winds ARE a problem. I use a higher than normal
throttle setting, use continuous wheel braking but pulse the wheel brake
rapidly to momentarily lighten the tail for taxiing turns. Also the
inside wing tip can be dragged but often runway lights are in the way.
Full up elevator must be maintained, of course.
Ten meter radius turns are easily accomplished with the braking technique.
dno...@magnus.acs.ohio-state.edu NL (No Lift, NNeeds iron thermaLL)
Jukka Tervamäki
> From Ian Strachan, Lasham Gliding centre, UK.
>
> I have been an enthusiast for high performance motor gliders since I first
> flew a Schleicher K-14 in 1968, and have flown nearly 20 types of MGs from
> the early Scheibe SF 27M which set the basic engineering of the pylon, to
> my present Nimbus 3DM self launcher. I therefore have a contribution
> to this thread on MGs ......
Greetings from Finland!
I posted this story already once a couple of years ago but did not receive
many comments then. Now, I belive it is suitable for this thread once
again since it describes some aspects of motorgliding in practice.
I have flown some 30 hrs RF-4 and RF-5 (on the sixties) and 250 hrs a
Schleicher ASK-14, which I owned 1974-1976.
I then designed and built a retractable engine installation for a PIK-20B
glider with extensive modifications in the airframe. Therefore I gave a
new type marking for this experimental motorglider, the JT-6,
registration marking OH-520X. My motorglider is is actually the
prototype and test bed for the PIK-20E motorglider which is quite well
known in the soaring world since most of them were exported around the
world. A full story of my machine was published in HOMEBUILT AIRCRAFT,
August 1980 as well as a short story in SOARING magazine, Feb. 1979.
Since the first flight in 1976 I have logged 1438 hrs of which 97
percent is soaring and the rest by power for take offs and some
"retrievals".
My best (soaring) duration is 8 hrs and and the best soaring distances are
a couple of 600 km triangles. I have a Finnish speed record over a 300 km
triangle for motorgliders from 1979, long since broken by others.
When operating an experimental motorglider one gets the maintenance
problems of a glider, powerplane and experimental aircraft combined. This
is reflected from the following list various problems but remember, both
the airframe and and engine were experimental developments and the list
covers 19 years of flying. Actually two different engines were tested and
flown in the machine:
- a Canadian Kohler, 33 hp. It was found to be too low powered
- an Austrian Rotax 502, 45 hp. At the time of the installation in
1977 this engine type was brand new and my installation was the very
first for it in any aircraft.
The problems and defects have not much affected my flying. All the early
chronic problems have disappeared due to continuous improvement. The two
engine sizings could have been a problem at low altitude, but
fortunately, in both cases I already had a thermal at 1500 feet and
could crank the engine in and continue by soaring for hours, in this case
as a pure glider since the engine could not have been restarted again.
OH-520X PROBLEM STATISTICS
CHRONIC PROBLEMS
Cracks in engine cooling baffles, 1976.......1985
Cracks in muffler brackets, 1976......1987
Propeller hub main bearing nut getting loose, 1976.......1985
Tail wheel steering spring corrosion, 1976......1984
RANDOM DEFECTS
Fuel filter blockage, 1979
Flap mechanism bracket breakage, 1980
Engine sizing due to lean mixture (own mistake), 1982 and 1983
A hole burned into the piston, 1984
Cylinder head gasket failure 1985
Fuel return tube breakage, 1986
Fuselage epoxy bonding failed (30 cm length), 1984
Main wheel bolts broke (all three of them?),1989
Canopy hinges broke (due to limiting wire breakage), 1990
Radio malfunction, 1991
Engine extension limiting wire breakage, 1992
MAINTENANCE WARE, LIFE TIME OF SOME ITEMS
Battery, 16Ah motorcycle type, one year, seldom two.
Spark plugs, 3 years
Tail wheel, 4 years
Main wheel tire, 5 years
Some small engine control bushings (10 cent items), 2 years
OWN MISTAKES
Belly landing, one only so far
Tipping over (soft ground, too much throttle, a scratched belly), four times
It would be nice to see similar statistics from other SLS owners. Serial
production PIK-20E and other SLS types should not have the chronic
problems but random defects do appear in every machine, especially if
they are equipped with a 2-cycle engine.
The pilot mistake which seems to be the most serious one is a restart
attempt at low altitude. We have had some wreckages and total losses in
Finland due to this error. My personal minimum restart altitude is 500
meters or ever more if the weather turns hopeless and terrain below is
unlandable.
Now, I guess, some of you want to ask me the final and essential question:
Why to take all those troubles with an SLS when most of it could be
avoided by owning a pure sailplane? My very personal reasons are as
follows:
1. I love soaring but wanted to be totally independent. My wife does not
drive and hates to spend her time on airfields. I have no other crew
either.
2. I wanted to do soaring from the busy Helsinki Malmi general
aviation airport and therefore designed the machine to be fully taxiable.
I actually flew from Malmi airport the 1978 soaring season and could
continue even now but the increased traffic on the nearby Helsinki
International Airport and, above all, the new bureaucratic limitations
and the enormously enlarged Helsinki TMA prevents this.
3. I have no glider licence at all, only a motorglider licence.
Consequently the OH-520X has no tow hook. It has no water ballast tanks,
gyro instruments or oxygen system either. South Finland has no mountains
for wave soaring opportunities. (Most serial production PIK-20E machines
are fully equipped with all of the above gadgets).
4. I hate the possibility of an off field landing. Fortunately, so far
the Rotax has saved me from one. If I ever have to make one it sure is
"interesting" since I have no experience.
5. I love designing and homebuilding. This is my 6th design. Four of the
previous ones were autogyros. In addition I have been a project manager
for one fixed wing project, the PIK-19 Muhinu towplane.
6. All the experience I have gained with my JT-6 has fueled my imagination
and resulted in a dozen or so "motorglider concepts" on my Macintosh
hard disk (thats all). I definitely would install a 4-cycle engine given
a chance to do it once again. However, modifying an existing glider
requires a lot of lead ballast on the nose to counterweight the engine on
the back, not so good compromise structurally.
Happy motorgliding to all of you!
Fabie...@free.fdn.org
> You missed one
> 3) The engine takes a finite time (and therefore height loss) to start.
> If its a retractable engine you will have to add the height required to
> extend the engine. Some engines rely on you diving to produce
> sufficient air flow over the propeller to bump start it. These factors
> all add up to having to have a much higher field selection altitude if
> you have an engine than if you don't (and you still need a field
selected,
> what if the engine doesn't start?). The drag caused by an extended
> engine that failed to start also needs to be considered for the circuit.
> --
> Geoff Brown
> G.B.D...@bnr.co.uk tel +44 1279 402716 fax +44 1279 402485
> BNR Europe Ltd., London Road, Harlow, Essex,U.K.
3) is not true for the STEMME S10 (retractable propeller) virtually no
height loss.
Fabien
--
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Fabie...@free.fdn.org (NextMail/MIME accepted)
Fabien Roy Consultant
NEXTSTEP/OPENSTEP/EOF Consultant, SYBASE DBA
10 rue de la DEFENSE 93100 MONTREUIL, France
Tel: 33 1 45 28 32 23 Fax: 33 1 48 55 09 90
David H Noyes
Geoff Brown <G.B.D...@bnr.co.uk> wrote:
>
>3) The engine takes a finite time (and therefore height loss) to start.
The Ventus cM takes 9 sec to extend another 6 to start if everything goes
right. This adds up to about a 200 to 300 foot loss, if everything goes
right!
I wish the manufacturers would use Herb Abram's design for
retractable engine mounting. The engine in his Solitaire took less than 2
seconds to deploy and another 2 or 3 to start.
> These factors all add up to having to have a much higher field selection
>altitude if you have an engine than if you don't (and you still need a
>field selected, what if the engine doesn't start?).
This is all very correct. You cannot "go anywhwere" in a motorglider!
Eagle Data
information of your experiences. I'm in the process of purchasing a
self-launcher and the information you and others have provided is very
helpful.
John Duprey
Std. Jantar
IL, USA