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Thread: the future of STOL

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    Member RocketRick's Avatar
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    Default the future of STOL

    Gruman-Northrup proved the power to weight ratio with the F-5.

    Some heads up person with vision will do the same for STOL.

    They'll put a turbo engine behind a a stol wing and revolutionize bush flying..

    You heard it here first ha!.

    The General Electric J85 is a small single-shaft turbojet engine. Military versions produce up to 2,950 lbf (13.1 kN) of thrust dry, afterburning variants can reach up to 5,000 lbf (22 kN). The engine, depending upon additional equipment and specific model, weighs from 300 to 500 pounds (140 to 230 kg). It is one of GE's most successful and longest in service military jet engines, the civilian versions having logged over 16.5 million hours of operation. The United States Air Force plans to continue using the J85 in aircraft through 2040. Civilian models, known as the CJ610, are similar but supplied without an afterburner, while the CF700 adds an uncommon rear-mounted fan for improved fuel economy.

    RR

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    Can you imagine the number of forest fires a bush plane with afterburners would start!
    Normal people believe that if something ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.

    Scott Adams

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    Quote Originally Posted by Toddler View Post
    Can you imagine the number of forest fires a bush plane with afterburners would start!



    Ya don't use that less the FAA is after ya! Ha!

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    I know this is a little bit of tongue and cheek. There is acquisition costs and operating costs and when you get into jets of any kind, it takes a lot of money to buy operate and to maintain. What is needed is small engines that are light for there size that can put out the horse power we need in the types of airplanes we currently fly, Ie a PA-32-300, now if they could come up with and engine that weights the same and puts out the same hp as the IO-540 Lycoming. But run on Jet-A with the same fuel consumption numbers or a little less, then you would really have something. With the EPA screwing with avgas and there is nothing to take its place at this time that will work as well as the current 100 LL we in GA has some serious problems on the horizon. Never mind the 30 to 60 year old and older airplanes we fly.

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    BH - You have a lot better handle on this then I do. I thght it wld be a good topic but maybe your right.

    Cant ya scale down the engine or is it...."if it could be done it would have been done...?

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    Rocket Rick, you first have to understand how a jet engine works, they do have small jet engines, they put them on the Light Jet airplanes, every single one of them are in the million dollars ! range, and well you need a bit of runway for take off and landings. Then there is the issue of FOD. That is foreign object damage. There is also it takes time for a jet engine to spool up and put out the thrust, Not Ideal in short gravel strips or off airport all together landing areas bush pilots go to. The Ideal is a Helicopter, because you can fly on the Veritcal, but helicopters unless you have some serious work for it or there is no other way is way to expensive to fly for the part 91 operations most who just own an airplane for personal use. I think the engines of the future for GA is going to come down to two types, Diesel and turbine. if they can get the weight and reliability issues solved its going to be the way to go I think. Roll Royce has got a turbine engine for airplanes that currently use the I0-540's type, its the R-300. Its a great engine. But there is one little problem, its about 500,000 to hang it on a Cherokee Six! So there is the problem, its going to be money as it always is with aviation. A new Cessna 206 a popular bush airplane, you would have to write a check north of 550K. Its not going to perform any better than say a 1978 version, except you get the G-1000 in a new one. but the 1978 version might only set you back 150K for a bush operator, you could not afford to by new. Nor could they afford to buy a small jet as you propose. When the Fed so stuff they tend to spend money nobody else can do, since the feds tend to just print money. Private sector business can't operate that way. As it is for the most part you want to loose money, invest it in aviation. Profit margins are very tight in this business ask anybody that is making a living doing it. The market in bush alaska would not be able to afford the prices you would have to get for that kind of aircraft, its one thing to put a snow machine in Anchorage on a 727 and ship it to oh say Nome, You can carry a lot on a 727 so the cost per pound is some what reasonable. now put that same snow machine on your light jet powered bush plane, that can just carry that and maybe enough fuel to fly from say Nome to St Mary! now you have a freight charge that would be almost as much as what you paid for the snow machine, and with the way jets suck down fuel, you have the other problem, fuel distribution. Not every village has aviation fuel, and then if you have to start doing that, well there is transport costs for that fuel in the roadless areas. Of course they looked at it, but like a lot of things, the reason why we fly the airplanes and to some extent the helicopters we fly is because a. they work, b. affordable c. you can price your transport services at a rate your customer base can afford to pay. And there is the other thing, you go to jets and it don't make any difference to what the gross weight of the aircraft is, you have to get a type rating for that aircraft. So the general 12,500 lbs or more is a type rating is out the window. Flight Safety or Simcom are not cheap, and the insurance companies price accordingly. I am convinced that GA is going to have to get away from avgas 100LL because of EPA and some loud mouths that are pushing for the ban on it. Jet A is a safer fuel and in most parts of the world its the only aviation fuel you can easily find. Besides there is just one refinery that makes it, and when you get down to it is a low volume thing. GA dose not use a whole lot of fuel when you get down to it. When I started flying you could get 5 grades of Avgas, then it became three than one. I am not that old at 57. In the current economic conditions, being able to cut costs is king. for what we do, jets is not the way to go.

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    BH - so much for that idea ha!. Enjoyed reading your thoughts.

    I bought a 133 gal Mogas tank and fuel pump/nozzle. Each time I fill it up, well last year, I saved $200 over the cost of 100LL. That makes sense to me.

    I guess the price of fuel is what is driving Pen Air out of the Bush FBO work.

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    While I love the idea of out of the box speaking, and I DO believe that the FAA needs to get their heads out of the '30s when it comes to engine certification (or out of it all together for at least non commercial intrastate a/c), a jet as a bush plane would be a tough sell for me. Jets burn an extraordinary amount of fuel per hour. The way to make up for it is speed... you don't need as many hours to get there. However, in a STOL high drag, high lift wing, you would not be able to get the speed to make a jet worth it. Also, a jet makes burns a ton more gas at low level, so that throws another kink into it. What I'd like to see is an autogyro hybrid with turboshaft power, and a translational rotary/fixed wing that can make the best of both worlds. Of course, if that were feasible, the Osprey wouldn't exist. On that note, with today's certification standards, non of these would be affordable to a regular joe at any rate....


    Now, Rocket Assisted TakeOff, now that's another story. Hmmm

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    Akheloce - There are many swept wing planes that have extendable flaps AND slats to get lower speeds at landing.

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    Quote Originally Posted by RocketRick View Post
    Akheloce - There are many swept wing planes that have extendable flaps AND slats to get lower speeds at landing.
    True, I fly (crewmember, not pilot) one... the C-17.

    The reason I have a bit of interest in this thread is due to my experience with the C-17.

    While I love my airframe, it's NOT an Alaskan bush plane, even if it were smaller. The way it is currently utilized is very inefficient as well (long haul). In ground school, I learned what a "drag producing device" is- flaps, slats, spoilers, etc. The C-17 IS a drag producing device. In order to have all those things that make it STOL, it has a very thick, complex wing, that no matter how much it is cleaned up, is still a very high drag wing. The sweep is not enough to make it efficient at high speeds- making it more so would reduce it's center of pressure tolerances so much that it's slow speed capability would be dramatically reduced. An example of this is the crash of 2010. The wing sweep was a huge influence in why it could not make the turn the pilot was attempting- related to the center of pressure tolerances.



    At cruise, a C-17 is burning nearly twice as much gas as a similar gross wt. aircraft, while cruising at only mach .74. In order to get the benefits of a high thrust jet engine, it would either have to be a slick low drag wing to go LONG distance and have a long runway, or have a high drag wing, hauling heavy weight a short distance-- however to do that, the gross weight would have to increase an inordinate amount to carry the extra gas needed due to the nature of jets, reducing the useful load, and costing a buttload to the operator.

    A turbo prop, on the other hand is a decent compromise since although a turbine, the propeller can use the power of a jet, with the efficiency of a propeller.

    I guess what I'm getting at, is that a billionaire who wants a toy, could probably make a short hauler bush plane for a jet, but it would be little more than a toy, and no one could afford to operate it in a cost effective manner.

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    What about turbo fans or a combo helicopter plane?

    I guess the harrier engines are too heavy but that plane does vertical and carries heavy ordinance. Maybe scale down those rotatable thrust jets?

    RR

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    Turbo fans: same thing as a jet... although less inefficient (just not enough to get us over the power for fuel hump)

    Combo helicopter: You bet! that's why I love the idea of a modern autogyro (I'm not smart enough to improve on current designs)

    Harrier types: I see those as great in theory, and I'd love to be the A&P to send my kids and grandkids to the Ivy League due to the complexity.

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    Akheloce - Watched the video. Interesting for sure. Good explanation of why.

    I'd never done the moose stall but went up with an ex AF pilot and now a comm pilot. The 180 with the Sportsman STOL mod cant hardly be stalled. At least with level or close to level wings.

    We went up and he got me into a tight LEFT turn at low speed and had me kick the left rudder. Guess what occurred? Man that left wing went down qwik. I was amazed it happened so fast. No burbling or shuddering just a abrupt loss of lifT on that left wing. It was actually scary.

    That was the 1st time we had flown together and he was making sure I knew how to avoid it. A REAL GOOD LESSON!.

    rr

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    Quote Originally Posted by RocketRick View Post
    Akheloce - Watched the video. Interesting for sure. Good explanation of why.

    I'd never done the moose stall but went up with an ex AF pilot and now a comm pilot. The 180 with the Sportsman STOL mod cant hardly be stalled. At least with level or close to level wings.

    We went up and he got me into a tight LEFT turn at low speed and had me kick the left rudder. Guess what occurred? Man that left wing went down qwik. I was amazed it happened so fast. No burbling or shuddering just a abrupt loss of lifT on that left wing. It was actually scary.

    That was the 1st time we had flown together and he was making sure I knew how to avoid it. A REAL GOOD LESSON!.

    rr

    Thanks, out unit commander made us watch it after the crash... I wish we would have seen it before the crash... perhaps the outcome would have been different.

    I'll tell you what, this thread has me thinking more and more about the autogyro thing. I was just doing some more research about autogyros, and what the newer ones are capable of, and I'm impressed!
    http://en.wikipedia.org/wiki/Groen_Hawk_4

    This one has a 1,000 lb useful load, and cruises at 130, with a 600 mile range... hmm.

    The Alaska DFG only restricts "helicopters".. so this would theoretically be legal. They'd probably change the law shortly after these were used in AK though.

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    Member RocketRick's Avatar
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    Akheloce,

    Thats a new one for me.

    I cld see that having potential. Leave the property, be at the Su or little Su or or other west side creeks in a few min and back with the fish ha!.

    I want one.

    Rick

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    The Gyro Copter in James Bond You Only Live Twice, got me razzed on gyros... back when it first came out in 1967....
    Little Nellie oh yeahhhh
    http://www.youtube.com/watch?v=cvbbQaIoaSM
    http://www.youtube.com/watch?v=o4B4sLO8XFQ
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    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
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    Ya know I used to have many many many dreams of me flying. Sometimes just over the terrain at other times getting away from something on the ground. Just floated up and took off Ha!.

    Funny tho,...now that I'm doing it, I don't have the dreams no mo!

    RR

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