Thanks
I've seen the three unit PBT array in action at Waikerie mounted on an
ASW20A. Starting the engines did seem very tricky and initial thrust
was low. Very slow initial roll and a very smooth surface needed for
the first few metres at least. But once it reached warp speed (80kts)
- off like a rocket - pun intended.
I have a video of a take-off if your'e interested.
https://www.qdrive.net/en/download/sharelinkdownloader.php?id=100853&key=FBX3tF62qGdthODxX42x8mXBNFjHsBjgCH6
Click the little upper left hard-drive icon with the blue down arrow
superimposed.
Be quick though - they've warned this site will be taken down on 31/5
for a software upgrade.
On 29/05/2010, at 14:52 , Mike Borgelt wrote:
Here's the link to the engine details.
www.desertaerospace.com/turbines.html
The engine has plenty of history as it was the core of the MiG29 APU.
a DaN is a DecaNewton which is close to 1 kilogram force.
So the engine has 112 Kgf thrust at full power(correct conversion
factor).
The fuel consumption at full power is around 1.1Kg/Kg thrust/hour so
you'll burn about 123 liters per hour at full tilt.
That thrust will be adequate for 850Kg gross Open class gliders and
the glider should meet CS22 takeoff distances at gross and climb at
just under 900fpm. No problem for an 800Kg Arcus.
So you only take about a 2.5 minute engine run (incuding takeoff
roll) to get to 2000 feet for a fuel burn of a little over 5 liters.
Better than aerotow! You can do the retrieve calculations too and
get someting like a bit over half the fuel burn of a car retrieve
and no exposure to the outlanding hazards. More fun also. Way better
fuel efficiency than an aerotow retrieve.
There's no vibration on the jet. I'm sure Bob has engineered that
engine mount so wobble isn't a problem. The Salto with that engine
flew at Avalon in March 2009. Wasn't very noisy either.
To get good retrieve range you want about 16 minutes of engine run
at full power to climb to 14000 feet. It will take longer as you go
higher but the engine burns less fuel too so you win and are going
in the direction you want to at 100knots+. Call it 35l fuel plus say
6 for launch plus another six as reserve. Under 50 l.
On an 18m glider you can run the engine derated which might be a
good idea as would reducing power once you are at 500 feet or so
anyway.
Bob will sell you one of those engines right now. The one he is uses
on the TST14 has a special bifurcated exhaust to direct the exhaust
either side of the fin.
I've got a pair of AMT Titans in the workshop www.AMTjets.com
40 Kg thrust each and each engine with accessories is under 5Kg
mass. For a 500Kg glider you only need run at 33-34 Kg each max.
This is good for EGT and longevity. No ballast only 28Kg each.
For gliders like Libelles at 350Kg gross a pair of AMT Olympus will
do(23.5Kg thrust each). I've designed a spark ignition unit so no
more glowplugs which seem to be the weak point of the small jets.
This got tested on an AMT Olympus last August and worked every time
as soon as the gas solenoid opened.
Check out the PSR link on the AMT website. I've bought the same
propane start gas bottles as they use. The AMT engines aren't as
fuel efficient as the PBS 100 but still quite manageable. Just a
little less fuel required on a 500 KG glider - around 40-45 liters
will do.
Mike
Mike
At 01:41 PM 29/05/2010, you wrote:
That is impressive - particularly the retract arrangement.
I imagine the fuel efficiency would be the only real issue. Perhaps
lateral wobble of the engine pylon under full thrust.
Mike would you happen to have an idea of burn and endurance?
Dion
On 29/05/2010, at 11:55 , Mike Borgelt wrote:
Talk about ancient and dangerous methods of launching all you want.
Here's 21st century soaring, Bob Carlton's latest jet glider.
http://www.desertaerospace.com/bonusjet_2010_05_25.html
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
since 1978
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
email: mborg...@borgeltinstruments.com
website: www.borgeltinstruments.com
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Borgelt Instruments - manufacturers of quality soaring instruments
since 1978
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
email: mborg...@borgeltinstruments.com
website: www.borgeltinstruments.com
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