Jet turbine reliability

Multiple engines (especially for self-launch) make a lot of sense since price scales neatly with thrust.

2X 230N thrust for a light single-seater, or 2X 800N for an open-class ship would allow a self-launcher with acceptable cruise fuel consumption and self-launch capability.

On Thursday, June 4, 2015 at 12:17:49 PM UTC-7, J. Nieuwenhuize wrote:
Multiple engines (especially for self-launch) make a lot of sense since price scales neatly with thrust.

2X 230N thrust for a light single-seater, or 2X 800N for an open-class ship would allow a self-launcher with acceptable cruise fuel consumption and self-launch capability.

That's close to what I came up with when investigating for a single seater. You would probably want to carry at least 15 gallons of fuel for the single. Interestingly, when you throw in oil and anti-static, the runtime cost are quite high. You end up finding how economical the old fashioned internal combustion self launch really is. It accomplishes quite a lot with 4 or 5 gallons.

That's close to what I came up with when investigating for a single seater. You would probably want to carry at least 15 gallons of fuel for the single. Interestingly, when you throw in oil and anti-static, the runtime cost are quite high. You end up finding how economical the old fashioned internal combustion self launch really is. It accomplishes quite a lot with 4 or 5 gallons.

So in the case of the M&D/JS-1, is it correct to assume the preferred fuel is Jet A? To Jet A, what specific oil and anti-static are added and what is the added ratio?

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.

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.

....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.