Jet Cat P200 read ad ......

Seems to me that a flameout at one tip might be a concern...

How about right at the end of the tailboom? It would require specific
engineering: the glider would have to be designed for it, both to fit
the engine there and from a c.g. point of view - although now that I
think of it, my glider already has tail weights to bring the c.g. aft!
The hot exhaust would be no issue. You'd have to duct inlet air from
the top of the tailboom to avoid ingesting foreign objects. Existing
gliders might be a little tough to retro-fit, but I'd imagine some
clever shops could do it (converting all the certificated gliders to
Experimental in the process, presumably...) As Chris says, you'd put
the fuel in the wings, displacing some (probably not all) of the
water, or put it between the wings in the fuselage. You'd have the
engine so far from the pilot and fuel, the exhaust aft of the
structure, and no complicated swinging arms, bomb bay doors, etc.

The noise in the cockpit would be pretty nasty, though...



Chris Ashburn wrote in message ...
It might get a pit toasty for the wing runner in self-launch mode, but
how about one at each wing tip?

It seems most gliders these days already have some sort of interchangable
tip, so make a new set with a jet built in.

Fuel storage would be the main issue. If you give up the water
ballast option though, there's plenty of room in the wing.

Chris

Slingsby wrote:

I would think that mounting a couple of small jets at or just behind
the wing/fuselage junction could also serve to remove some of the low
speed turbulence in that area. Also, if the engine had a tight
cowling around it then perhaps some water could be sprayed or drizzled
onto the outside of the engine and the resulting steam would mix with
the exhaust to provide some additional thrust. SWB Turbines in
Neenah, WI (SWBTurbines.com)has a Mamba turbojet which puts out 11
Lbs. of thrust. It is only 3.5 inches in diameter and would fit
nicely at the wing junction interface. SWB also has 45, 60 and a
100Lb thrust engine.

asemetrical thrust is one thing near the inboard section of the
wing... but at the outboard end of a high aspect ratio wing! All I can
say is holly crap hold on for one hell of a ride when one engine shuts
down early.

Is my brain fading or did that huge german transport sailplane in WW2
have a jato fail and the with the yaw created by the one rocket cause
it to take out the glider as well as 2 Junkers tow planes at the same
time?

Its a better world with centerline thrust! Mount two engines above the
fusalage and angle them so the thrust is directed to the side of the
tail feathers. The vector would be small and concentrated at the
center of mass if one engine failed just add rudder.

Rocket Science (for people that am smart like I is)



Chris Ashburn wrote in message ...
It might get a pit toasty for the wing runner in self-launch mode, but
how about one at each wing tip?

It seems most gliders these days already have some sort of interchangable
tip, so make a new set with a jet built in.

Fuel storage would be the main issue. If you give up the water
ballast option though, there's plenty of room in the wing.

Chris

Slingsby wrote:

I would think that mounting a couple of small jets at or just behind
the wing/fuselage junction could also serve to remove some of the low
speed turbulence in that area. Also, if the engine had a tight
cowling around it then perhaps some water could be sprayed or drizzled
onto the outside of the engine and the resulting steam would mix with
the exhaust to provide some additional thrust. SWB Turbines in
Neenah, WI (SWBTurbines.com)has a Mamba turbojet which puts out 11
Lbs. of thrust. It is only 3.5 inches in diameter and would fit
nicely at the wing junction interface. SWB also has 45, 60 and a
100Lb thrust engine.

Sailplanes = The Quiet Challenge

Jet Engines = Converters (they convert fuel to noise,
especially the ones in T-37 tweety birds)

Why would I want to fly something noisy? Many of us
in America already 'suffer' from towplane noise, so
why add the ear-splitting noise of a turbine?

I would rather see the further development of electric
self-launchers and greater use, in America, of ground
launches.

Leave the turbines to the Caproni (sp?) afficianados
and U-2/TR-1 pilots.

Ray Lovinggood
Carrboro, North Carolina, USA
LS-1d, 'W8'

In article ,
says...
Sailplanes = The Quiet Challenge

Jet Engines = Converters (they convert fuel to noise,
especially the ones in T-37 tweety birds)

Why would I want to fly something noisy? Many of us
in America already 'suffer' from towplane noise, so

Compared to similar electric powered gliders, a turbine powered one is
likely to be...

Lots cheaper

Lots lighter

Lots quicker and more convenient to refuel

Lots more climb height (kerosene has lots more energy per pound)

A guy has to love cheaper, lighter, quicker, easier, and more! I
confess I have no idea how noisy these units are, but perhaps the
manufacturers can learn to mitigate the noise, as they have the two-
stroke noise.
--
!Replace DECIMAL.POINT in my e-mail address with just a . to reply
directly

Eric Greenwell
Richland, WA (USA)

Combining some of the thoughts here with the earlier message string about
electric self launching gliders, I wonder if it wouldn't be possible to use
a ducted fan in the rear fuselage of a glider, exhausting thru the tail of
the boom, and driven by an electric motor? Some openikngs on the side and
top of the fuselage would provide inlet air. Some form of retracable tail
cone would cover the end of the boom once the engine was shut down. The
tail boom on most modern gliders would appear to be excellent ducts. Heat
wouldn't be an issue. If the batteries were quick change and quick charge,
they would only need to provide for one launch.

John Scott

"John Scott" wrote in message
...
Combining some of the thoughts here with the earlier message string about
electric self launching gliders, I wonder if it wouldn't be possible to
use
a ducted fan in the rear fuselage of a glider, exhausting thru the tail
of
the boom, and driven by an electric motor? Some openikngs on the side and
top of the fuselage would provide inlet air. Some form of retracable tail
cone would cover the end of the boom once the engine was shut down. The
tail boom on most modern gliders would appear to be excellent ducts. Heat
wouldn't be an issue. If the batteries were quick change and quick
charge,
they would only need to provide for one launch.

This is an idea that has also been running through my mind, but a
ducted fan does not have to be driven only by an electric motor. Piston or
even turboshaft power would do just fine. I believe that there are now some
ducted fans in the model world that are almost big enough to do the job.
You would not necessarily need the retractable tail cone, swing out
pressure-operated ducts on each side would also be a possibility. You could
use NACA ducts for the inlet, perhaps also equipped with simple closures.

Vaughn



John Scott

This is an idea that has also been running through my mind, but a
ducted fan does not have to be driven only by an electric motor. Piston or
even turboshaft power would do just fine. I believe that there are now some
ducted fans in the model world that are almost big enough to do the job.
You would not necessarily need the retractable tail cone, swing out
pressure-operated ducts on each side would also be a possibility. You could
use NACA ducts for the inlet, perhaps also equipped with simple closures.

I found a picture of the Funk Sirius 1 ducted fan motorglider (circa 1970) on
this page:

http://www.fk-lightplanes.com/FK-His...k-history.html

He also built a turbojet powered glider in 1960...

Marc

"Marc Ramsey" wrote...
I found a picture of the Funk Sirius 1 ducted fan motorglider (circa 1970) on
this page:

http://www.fk-lightplanes.com/FK-His...k-history.html

He also built a turbojet powered glider in 1960...

A bit more info on the Sirius I (and II which was based on the Calif), along
with pictures of another Calif-based ducted fan design:

http://www.gomolzig.de/englisch/antrieb/antrieb1.htm