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Thread: GA Turboprop

  1. #91

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    Quote Originally Posted by kjensen View Post
    Ok this will be my last question:

    Hypothetically if that TP-100 had lower fuel burn than a piston, let's say close to what a diesel engine burns (I know that it's not possible, but let's just assume that it was), and it was FAA certified. Would you still stick to the piston even if the price premium was "only" 25-50% over the piston??

    For sure, 25-50% premium for turbine power would change the landscape. Not overnight, but it would eventually push piston engine dominance aside in light planes. None of this is going to happen without a technology breakthrough, cause regardless of the name on the dataplate, can't manufacture a turbine engine at a price that will be competitive with current piston engines.
    Last edited by martymayes; 04-18-2012 at 05:58 PM.

  2. #92

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    Quote Originally Posted by steveinindy View Post
    The thing is that it is possible. The issue is that most GA pilots don't do the sort of flying that is suited to turbine engines to have that kind of efficiency. The average cross country flight for a GA pilot is somewhere between 100 and 200 miles. There's literally no benefit to it because even a ten or twenty knot difference in cruising speed over that short of a distance isn't going to make that much of a difference in time. Also take into account that to get to the "sweet spot" altitude for nearly any turbine is going to take you 30-50+ miles. For shorter flights, you'd literally go almost from cruise power to flight idle for the descent because top of climb and top of descent are going to be more or less the same point.

    Most GA flying does not make efficient use of piston engines. The average GA mission isn't about flying from point A to B on the most efficient climb/cruise/descent profile. Many times point B isn't even involved, flying is from point A to A. Sometimes people fly just to have fun with no concerns about efficiency, you know, see something on the ground so you circle around to have another look. Powering GA with turbine engines would be the greatest thing since the Wright Flyer. Unfortunately, it's not happening with current technology.

    I think you're going to be sorely disappointed flying a turbine engine airplane. Fantasy land is going to meet reality head on and they are not going to be anywhere near matching up.

  3. #93

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    Quote Originally Posted by Thomas Stute View Post
    I think we have to wait until Mistral finds a strong investor for seeing their engines certified.
    That would be the elusive billionaire that wants to make a small fortune in aviation......

  4. #94
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    Quote Originally Posted by martymayes View Post
    I think you're going to be sorely disappointed flying a turbine engine airplane. Fantasy land is going to meet reality head on and they are not going to be anywhere near matching up.
    How so? It's going to be expensive, kind of boring but it is a means to get from point a to point b. But then again I feel much the same about all flying: it's stretches of boredom punctuated by a couple of minutes of challenges. Maybe it would be different if I were into aerobatics or something. There's no magic or romance or any of the other emotions a lot of people feel towards aviation. It is a scientific and engineering challenge that allows me to learn and challenge myself. A fringe benefit is that I wind up with an interesting and somewhat useful aircraft. If I do it right, this will be rather dull flying in the minds of a lot EAAers. Routine and kind of dull in aviation is a good thing in most cases. I don't have an particular illusions about it. Care to elaborateas to what you mean?
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  5. #95

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    Quote Originally Posted by martymayes View Post
    For sure, 25-50% premium for turbine power would change the landscape. Not overnight, but it would eventually push piston engine dominance aside in light planes. None of this is going to happen without a technology breakthrough, cause regardless of the name on the dataplate, can't manufacture a turbine engine at a price that will be competitive with current piston engines.
    Thanks a lot for you input!

  6. #96
    Have you seen this development? It has gone quiet for a couple of years but it is not dead. This model is "only" around 100hp but an "affordable" upscale version is not outside the realms of possibility.

    What do people feel would be a price for a 150-180hp turboprop engine that would attract buyers? A new 180hp IO360 is around $32000, what do you think people would pay for a 180hp turboprop to use instead of the IO360 (up to 25% more as previously alluded to or the same price as the equivalent piston)? I'm curious what the general opinion is. The turbine would probably be 30% less efficient, but it could be a sub-120 lbs installation versus 280 lbs for the IO360. 160 lbs is a lot of weight to save on a sub-1000 lbs empty weight aircraft and would have to count for something. Sure, range is compromised due to the higher SFC of the turbine but how much would this come into consideration for someone considering such an engine?

    If a turbine cost the same as the equivalent piston, I would put such an engine in my project in a flash as fuel burn doesn't really worry me. The weight saving would count for a lot for me, but what do others think?

  7. #97

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    Quote Originally Posted by flyvulcan View Post
    This model is "only" around 100hp but an "affordable" upscale version is not outside the realms of possibility.
    I agree, it would be short-sighted for someone not to develop a potential family of engines from a single design. 100-400 hp and most of the GA fleet is covered. For 180 hp, 50% over 32k is $48k. All manufacturers would rush to get a turbine 4 place on the market and salivating buyers would line up to buy them.

  8. #98

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    Quote Originally Posted by flyvulcan View Post
    Have you seen this development? It has gone quiet for a couple of years but it is not dead. This model is "only" around 100hp but an "affordable" upscale version is not outside the realms of possibility.
    do you have any more info on that?? There's no details in the youtube video, very interesting looking design though!

  9. #99
    The turboprop in the video was by N2 Turbines. I had a link to their website and was going to post it but but I just visited the page, only to find that the site lapsed on 04/04/12 so is no longer available. You can find a little information about them on the web, including a second video of their engine. I can recall that either Sport Aviation or Kitplanes magazines ran an article on them a few years back.

  10. #100
    In the 1990's United Airlines was taking deliveries of B-757 's and I had a Pratt & Whitney tech rep riding jumpseat with us on a trip. UAVMX, when he finished taking engine parameter readings I asked him the EXACT question you have raised about a 300-400 hp turbo prop we could afford in GA. His answer was as long as we machine the blades we cannot get the cost down. I asked about making ceramic blades and he said they were working on that, but I have not heard anything about it since then. Adrian Bewley
    Quote Originally Posted by uavmx View Post
    I'm shocked in this day and age we don't have a nice IO550 alternative turboprop. Something in the 300-400HP rating that get's comparable fuel burn (probably higher). I think it would be a great seller, but as stated, cost is the big thing. But think about how much you save in MX, reliability, not replacing cylinders all the time, just overall hassle. The TBO on a turboprop could be much higher too. Just do a 2k hr hot section inspection, then fly it to 4k hours easy.

    There's got to be enough smart people that can get together and build something that fits those parameters.

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