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Turboprop Engines for Ultralight, Light Airplanes and Helicopters.


farri

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The best specific fuel consumption looks to be stuck with the reciprocating engines. Small jets must run at crazy RPMs( Reduction gear issues) and leakage at the fan tips become more critical in the smaller stuff.. White hot running turbine blades are expensive to make. . You can use a turbocharger to make one for yourself, but you don't have to make one to know what you are up against. Nev

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At 27kg/hr fuel consumption for the 100HP version, that translates to 32L/hr. The engines fuel economy isn't exactly going to be one of its best-selling points. It's the engine no-one is looking for.

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Small turbines have always been thirsty. Power to weight ratio is very good though. They spin at very high speed. My Hangar mates Helicycle has an APU from a Chinook and spins at around 65,000 rpm. He uses Jet A1 Kero and burns around 45 litres/hour. The heat from the exhaust is phenomenal and burns the grass whenever he takes off or hovers near the ground if there is no bitumen or concrete around. What percentage of the fuel disappears to heat I don't know.

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In terms of fixed wing application it might be better to look at litres per nautical mile travelled rather than litres per hour. A small turbine running at very high altitude might be able to outrun a naturally aspirated piston aircraft based on the fact that it has spare performance to compress thin air at 100% N1 without overheating or over torquing the gearbox. A Piper Cheyenne for example makes more sense than a Chieftan but only for some missions.

 

Of course you need to climb it up there first and might need supplemental oxygen in the cabin to stay there

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Guest Machtuk

A 100 HP is still a 100 HP despite how it's produced. I love turbines got more hrs behind them than I can recall BUT the cost in all aspects is astronomical compared to our recip donks! Mounted in a light A/C means to get any sort of efficiency out of them you would have to operate yr plane differently, height, fuel planning and structural considerations IE TAS at Alt. are just some of the considerations. Maint and General handling of turbines are far different than their IC cousin donk, it's hard to kill an IC engine instantly but you sure can a turbine!

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A 100 HP is still a 100 HP despite how it's produced. I love turbines got more hrs behind them than I can recall BUT the cost in all aspects is astronomical compared to our recip donks! Mounted in a light A/C means to get any sort of efficiency out of them you would have to operate yr plane differently, height, fuel planning and structural considerations IE TAS at Alt. are just some of the considerations. Maint and General handling of turbines are far different than their IC cousin donk, it's hard to kill an IC engine instantly but you sure can a turbine!

Agreed - two points:

100 hp (equivalent) turbo prop is really in the RAA category of aircraft & in Australia we are limited to 10,000 ft so you are never going to legally get the benefit of higher altitude opps.

Unlike the north America and Europe, we dont have high mountain ranges to get over, so even if the flight levels were available to RAA , the benefit would be doubtful.

 

But after that negativity I will confess to day dreaming about having a turbo prop (one day)

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it is aimed to be used in Europe and other places with leaded avgas for 3 euro per litre and A1 on usual price. In this case its better to eat 30 l/h of kerosene rather than 20 l/h of avgas - $40/h difference!

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Perhaps a niche application for these diesel-guzzlers would be to get a hybrid aircraft up to cruise level where electric power could take over; the batteries would have been saved the huge load of take-off and climbing, ensuring much greater cruise range.

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They have no character and smell bad. If something goes wrong on the start they just drip metal and commit suicide. They also need a pretty trick propeller and a REDUCTION gearbox of great reduction.'. Yes, they are many times more reliable that INFERNAL combustion engines of the reciprocating kind where you just sit and wait for something to happen and some part of the insides ends up on the outside.

For the time being, live with the challenge, and get the best out of whatever is up the front (generally) understand it and fly like it may stop at any time, then you won't be too surprised and of less use. Planes still fly when engines stop, (unlike in most movies)..Nev.

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Perhaps a niche application for these diesel-guzzlers would be to get a hybrid aircraft up to cruise level where electric power could take over; the batteries would have been saved the huge load of take-off and climbing, ensuring much greater cruise range.

 

Your comment sound reasonable to the unlettered (me) and was also used as a suggested application for the waknel. In both cases, potentially very smooth running, high power to weight ratio and both pretty thirsty.

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More efficient to do it the other way around.

 

Use a rotary as motive power with a pancake motor on the flywheel. The battery pack gives boost to climb, thus only a small motor needed for rotary to keep height. Excess goes back into batt for later.

 

So you optimise the power pack for level flight and use a much smaller HP engine and fuel flow. The big power needed for climb is electric and rotary.

 

Such a system could be 5 litres a hour including climb instead of 15 hr.

 

Figures are just made up but this will be the future esp when combined with solar cells on ground and on wings.

 

Battery and controller can be much smaller and lighter. Eg only needs 50 HP for a short 5mins etc and a 10 kg batt at most.

 

The idea been the total weight of package including fuel,batt,systems and small rotary are the same as a original system and fuel full on a much bigger tank.

 

So for a range if 600 kms instead of 60 liters it would use only 25 liters. In theory.

 

The more slippery the better.

 

Hybrid will be a very big deal in 10 years.

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Note ....a proper designed pancake flywheel should weigh about the same as a full flywheel. So no great weight penalty. Nor size issues.

 

The penalty is the weight of controller and small batt pack. If that is same as fuel saved, a instant winner. Even with a small weight penalty of 10-15 kg it still makes a lot of sense.

 

We have discussed this at length on HBA forum. I have looked at this for years and followed the tech as matures.

 

This is already the big thing in UAV circles esp from NASA.

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