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Thread: Turbines

  1. #1

    Default Turbines

    What do you all think about turbines in the bush. I know that you can buy some Maule with turbines. They say they can start w/ out preheating even in virtually any climate. Turbines can run on Diesel, Jet-A, and Kerosene. I got this info from Innodyn. I know Maule uses another brand but oh well. The bad thing is they burn 25GPH!!! It would be nice because they are fast and can climb faster. I think a 235hp or 260hp piston would almost be better. Not considering the cost of engine here but 25gph is a lot of fuel vs 10-15gph. What do you all think about turbines.

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    Default Grizzly 1

    Quote Originally Posted by Sharp Shooter View Post
    What do you all think about turbines in the bush. I know that you can buy some Maule with turbines. They say they can start w/ out preheating even in virtually any climate. Turbines can run on Diesel, Jet-A, and Kerosene. I got this info from Innodyn. I know Maule uses another brand but oh well. The bad thing is they burn 25GPH!!! It would be nice because they are fast and can climb faster. I think a 235hp or 260hp piston would almost be better. Not considering the cost of engine here but 25gph is a lot of fuel vs 10-15gph. What do you all think about turbines.


    You have a really fat checkbook?

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    Talking

    Last time I flew a Twin Otter, it burned almost 600 #'s of jet fuel per hour. That's about 82 gallons. The C-208 I flew burned a little less than half of that. They can carry just about anything you care to haul...you just have to rob banks to operate them.

  4. #4

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    Turbines are awesome, but not without their tradeoffs. Loads of power, but burn lots of fuel. So, you have to pack more fuel, or allow for shorter legs, and pay for the fuel.

    Turbines seem alot less likely to fail in flight due to a mechanical problem. However, the phase checks on them are very involved and not that many mechanics can do them. If something is found and you need a new hot section you will think the cost of a brand new io550 is a steal. Also, while operating turbines is fairly simple, bad things sometimes happen on starts. Especially if you do not have a well charged battery, like what might happen if it sits for a while in really cold temps.

    For me, I think that the costs of the turbine and the maintenance on them rarely justify their price. But, if you have the money and the ability, they are pretty cool.

    Doug

  5. #5

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    They would be awesome to own but not that practical for the bush I guess.

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    Turbines are very practical in the bush. Twin Otters, Pilatus Porters, turbine Beavers, Caravans, Skyvans, Volpars, 1040's...they have all flown millions of miles in bush Alaska since the 60's. Some better than others but the point remains that their practically is moot without an operation that can sustain it.

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    Member ak_powder_monkey's Avatar
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    Default

    what does a piston beaver burn ~25 gph right? What about a turbine beaver?
    I choose to fly fish, not because its easy, but because its hard.

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    about 45 gallons an hour if I remember right. That's with over a 200 HP increase over a radial.

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    Thumbs up Other way around

    Quote Originally Posted by Sharp Shooter View Post
    They would be awesome to own but not that practical for the bush I guess.
    In my opinion it would be, They are awesome for the bush but not practical to own, that is unless you've got deep pockets
    my .02
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    Not much really practical to own anymore. My dad bought a 58 supercub with floats, wheels, and skiis in 64...for $7400.00 They bought bulk fuel for .34 per gallon. They would never know how good they had it. Oh well, it's only money! That said, make mine a Goose.

  11. #11

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    Turbines are without a doubt the most reliable and economical to operate, BUT, you have to have the volume of work to keep them producing revenue to justify them. Tubines do burn more gal/hr, but they are capable of doing so much more work (revenue) per hr. In an ag application turbine operating cost per hour over a 2500 hr period is actually less than an 300 hp cont or lyc, but you need to be very efficient bussiness wise and be able to max revenue.
    Typically, an airplane becomes faster, bigger load cap, and less drag (more efficient) than it's piston brother. You will probably take off with more weight in a shorter distance and climb quicker at a high fuel burn, but then be able to power back and or climb to higher altitude where the turbine really excells over a piston.

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    Turbine conversions are fairly popular in my area for Beavers and single Otters on floats. These 135 operators are using them for long over-water flights to the Brown Bear viewing areas.
    Plus we have the Twin Otter that comes down from Los Anchorage and the Cessna 208 Caravan.
    Plus the various helicopter outfits here use turbines.

    Some of the short haul 135 guys had considered using turbines, BUT on short hauls they are not practical. I was told that this was a problem of cycles (how often the engine was turned off and on) and not a problem of actual hours on the engine.

    Back during my short time with an MH-60 Pavehawk unit, it was nice to feel the power of two turbines above you that developed 1,970 shaft horse power, EACH.
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
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  13. #13

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    Like any mechanical device, heat is a killer. The most heat damage to a turbine is during a start where you go from ambient temp to in excess of 1000 degrees F in a few seconds. After that, temp change from idle to takeoff power is only a few hundred degrees.
    Basically a cycle consists of a start, takeoff, flight for about an hour and landing. With different formulas to come up with an average cycle count for specific operating conditions.
    In my ag conditions, for example, P&W recomends 1 cycle per hr (I would ave 1 start and 12 takeoffs in 6 hrs of flight) Also in ag the formula took in consideration the fact that you are constantly forcing that expensive gyro up, right, left, down, right, up (all in a 15 seconds) every 30 seconds. The start is the biggest factor, takeoff 2nd. Straight and level cruise being the least important factor.

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    yup. Go over 950 in my PW-121 and I'm looking for another job. Heat, FOD, oil loss...things going around in circles really fast are kinda unforgiving when things decide to go south in a hurry. To be fair though, I've more than 12000 hours in front of Pratt turbines of one kind or another and only had two failures. Engine air failure, frozen P3 line caused my engine to fall to idle. And tossed a stator on another..a bit more exciting. Im sold on the PT6.

  15. #15

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    What do you consider an average short haul?

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    The short hauls around my area are to the villlages across the bay, 15 minutes to Seldovia, another 8 minutes to Port Graham and then 3 to 5 minutes to Nanwalek, followed by 20-25 minutes back over to Homer.
    Shuting down the engine at each village to shuffle people and cargo.
    If you do that 5 to 9 times a day, you are talking about 20 to 40 starts per day. That would probably be kinda rough on a turbine.
    Plus that is on sand and gravel runways. Except on this side of the bay.
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
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    I don't know if this plane is being talked about in another thread or not, but the new turbine-powerd Quest Kodiak looks to be quite an airplane:

    http://www.questaircraft.com/index.p...ame=kodiak.php

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    Default

    hmmm looks like someone ripped off the Caravan. Intruiging though..

  19. #19

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    one thing to remember about Turbines is you can run Diesel or Kerosene in some of them. Diesel is now cheaper than Unleaded from what I have seen so that would not be too bad price wise. You may burn more fuel but you will there faster. If a piston you burn less fuel but you will be in air longer.

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