Jet turbine reliability

The M+D turbine manual specifies diesel or JetA1 mixed with 4% 2 stroke oil or Aeroshell 560 turbine oil. The tanks are about 42 litres. It gobbles fuel but a one way direct climb and glide retrieve flight will be cheaper than a return road retrieve (by the time you add fuel and vehicle depreciation etc)- but obviously more than a turbo retrieve.

Just curious are you putting the jet into a JS-1 or some other aircraft?

On Thursday, June 4, 2015 at 5:34:36 PM UTC-4, wrote:
The M+D turbine manual specifies diesel or JetA1 mixed with 4% 2 stroke oil or Aeroshell 560 turbine oil. The tanks are about 42 litres. It gobbles fuel but a one way direct climb and glide retrieve flight will be cheaper than a return road retrieve (by the time you add fuel and vehicle depreciation etc)- but obviously more than a turbo retrieve.

Gobble as well as gulp...with Jet A at +/- $5 a gallon and AeroShell 560 at $15 a quart that works out to north of $100.00 to fill up the JS-1. Still certainly preferred to landing out a gold-platted crystal slipper 90 miles from home.

So lets round off to $1.00 per M&D jet sustainer mile. Retrieve would be $.65 to $.85 a one-way mile so 180 x $.75 = $135. Certainly not a Solo but still cheaper than a retrieve by road or aero.

Plus a decent dinner for the retriever ...



On Monday, June 1, 2015 at 4:31:42 AM UTC-6, Jim Pengelly wrote:
I'm considering ordering a JS1-C TJ with the jet turbine. A potential syndicate partner is concerned about the reliability of jet turbines from a 'will it start' point of view and a repair cost point of view. I imagine electric turbos are going to be more reliable because of the relative simplicity but you can't buy an electric JS1 or 29. Any comments on jet reliability?

"Gobble as well as gulp...with Jet A at +/- $5 a gallon and AeroShell 560 at $15 a quart that works out to north of $100 to fill up the JS-1"

Well......you could certainly calculate a worst case scenario like that. But as 11USG of Diesel / 2-stroke (4%) oil mix is flight manual approved, this may be a more commonly employed option.

(US prices: 10.6USG @ $2.70 + 0.42USG & $20) is $37.

Glider pilots: Tighter than a fish's a....... :P

The HPH Shark takes 28 liters of Jet A1 + 4% Aeroshell 500. That will
give about 55 minutes cruising at 80-90 knots... The technique is not
climb and glide, rather dolphin flying... pulling up in any residual
energy and in notime you have gained quite a lot of height... It works.
Typically The Shark Jet will do 170km on a tank. The FES version will do
about 100km, whilst the Shark MS (Self Launcher) will do over 300km
on a tank...

Craig

At 08:30 05 June 2015, wrote:
"Gobble as well as gulp...with Jet A at +/- $5 a gallon and AeroShell
560
at $15 a quart that works out to north of $100 to fill up the JS-1"

Well......you could certainly calculate a worst case scenario like that.
But as 11USG of Diesel / 2-stroke (4%) oil mix is flight manual
approved,
this may be a more commonly employed option.

(US prices: 10.6USG @ $2.70 + 0.42USG & $20) is $37.

Glider pilots: Tighter than a fish's a....... :P

At 10:10 05 June 2015, Craig Lowrie wrote:
The HPH Shark takes 28 liters of Jet A1 + 4% Aeroshell
500. That will
give about 55 minutes cruising at 80-90 knots... The
technique is not
climb and glide, rather dolphin flying... pulling up in any
residual
energy and in notime you have gained quite a lot of
height... It works.
Typically The Shark Jet will do 170km on a tank. The FES
version will do
about 100km, whilst the Shark MS (Self Launcher) will do
over 300km
on a tank...

Craig

Interesting thread but surely if you are proposing to spend
£100K on a jet self-launch the cost of the fuel is a minor
matter? For some people the range will be the overriding
factor, if you are not in this category starting reliability might
be more important.
Jet and two-stroke technology: probably will start?
FES/Electric technology: almost certainly will start?

Ask this question: when pick up a Hoover do you think: Will
it start? When you pick up a two-stroke strimmer or chain
saw do you think: Will it start?

David W

....And let's not forget to amortize the extra $40-50,000 for acquisition
cost. So, if you land out 40 times during the life of the glider, don't
you also add $1,000+ to the cost of the retrieve?

Neglecting, of course, resale to someone else who doesn't want the
adventure of a field landing.

On 6/4/2015 7:54 PM, wrote:
On Thursday, June 4, 2015 at 5:34:36 PM UTC-4, wrote:
The M+D turbine manual specifies diesel or JetA1 mixed with 4% 2 stroke oil or Aeroshell 560 turbine oil. The tanks are about 42 litres. It gobbles fuel but a one way direct climb and glide retrieve flight will be cheaper than a return road retrieve (by the time you add fuel and vehicle depreciation etc)- but obviously more than a turbo retrieve.
Gobble as well as gulp...with Jet A at +/- $5 a gallon and AeroShell 560 at $15 a quart that works out to north of $100.00 to fill up the JS-1. Still certainly preferred to landing out a gold-platted crystal slipper 90 miles from home.

So lets round off to $1.00 per M&D jet sustainer mile. Retrieve would be $.65 to $.85 a one-way mile so 180 x $.75 = $135. Certainly not a Solo but still cheaper than a retrieve by road or aero.


--
Dan Marotta

Neglecting the resale value is a big aspect to neglect. I have only once lost a little money after selling part or all of 9 gliders over the years. Moreover I would far rather have a sustainer than a motorless glider to sell. In Europe e.g Discus BTs and Duo Ts are selling for significantly more than the original cost.

I've been working on the jet glider concept for over 10 years. 5 years ago, after a false start with somebody who never delivered what was promised I bought a couple of AMT Titan engines and have almost finished fitting them to my Ventus C 17.6 A fuselage. They are fully retractable. Just some electrical connectors to go and we're ready to do engine runs.
Yes if one engine makes a turbo, two make a self launch and two are better than one even if the installation is a little more difficult. As a slight bonus two Titans of 400N each are in fact cheaper than one Nike of 800N thrust from the same manufacturer.

Fuel consumption: Should get to 2000 feet above ground for around 5 to 6 litres of jet A/jet oil 4.5% mix. Compares favorably with aerotow. Retrieves cheaper than by car, without the outlanding risk and way cheaper than aerotow retrieves. I made a jet performance spreadsheet for takeoff and climb performance. Seems to validate against flying jet gliders. Predicted climb without water ballast nearly 800fpm (SL, standard day at 70% thrust on both engines. Will still climb 280fpm on one and 400fpm on one at 85%. Retrieve range close to 250km. I got 45 litres of fuel and the engines into the A model fuselage without impinging on any space used by pilot or equipment.

Noise: Enough installed thrust and good rate of climb means you're away from the ground quickly. Use airframe shielding and aviation industry noise reduction methods. Existing jet gliders do none of this. I saw and heard Bob Carlton's Super Salto at Avalon in 2009. It wasn't very noisy at all. Neither, I am told, was the Jet Silent he flew a couple of years earlier. I've got a couple of translating ejector nozzles just like the early DC-8 although in this case they are translating in order to minimise engine length for retraction.
Don't forget the noise stops at top of launch, unlike that from a towplane.

Safety: There are two things that can go wrong with the jets. They could catch fire or have a RUD event. I have a fire detection system and Halon fire extinguisher system for the former and 4130 steel around the compressor and turbine sections and the engine compartment is lined with fiberfrax over 8 layers of 170 gram kevlar. The Titan turbine blades are almost the same mass and speed as a .22LR rifle bullet so I took out the .22 and made some samples and tested.
A few years ago a bad batch of compressors made it into model airplane jet world. I gather when they failed some bits dribbled out the front of the engines. I'm not too worried about this.

Operations: Two engines means that launch failures should be rare. You only need to get one out of two running to fly away from a potential outlanding and extending the engines is not a large drag increment. The engines will NEVER be run at 100%. 70% is enough to meet CS22 takeoff at 410Kg and at 500Kg 85%.
Best retrieve range is by running both engines. Should get to 17000 feet above engine start point after a 2000 foot launch.

As for a few other points raised he The engine in the 304 jet appears to be a Titan with external shielding and I'm told the M&D engine internals are bought from AMT and are the Titan. The Titan seems to be rapidly becoming the standard 400N thrust engine.Certainly seems to be from what I saw. No external shielding which may be why the difficult and expensive EASA certification process just like Draline with the AMT Olympus(8 years.Different starter and case and I'm told, combustor section.
Certification will be the death of this sport.It will make anything vastly more expensive, particularly in a low volume business like soaring.

Anyway, I'm looking forward to having this flying over the next few months and the test flying program should be a lot of fun.

I'm also looking forward to hearing about the flights of the GloW. Should be a fun glider and the electric wheel is a fine idea.

I'll also be testing the new total energy system which completely rejects horizontal gusts and two other new ideas which may change the way glider variometer systems are done.

Mike Borgelt
Borgelt Instruments