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Thread: Kitfox engines

  1. #1

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    Default Kitfox engines??

    Hi Everybody,
    Still building that KF3 with the 582 greyhead in the box and I still cant get comfortable with that 2 cycle. Has anyone ever put a small gas turbine or the like in a KF. I like the power to weight ratio but my mind gets the jitters when the word 2 cycle sputters by . I can do dead stick landings all day but would rather be a choice as my heart is not as strong as it use to be. How about electric? Didn't want to spent the bucks for the 4 cycle but wouldn't mind something different.
    Last edited by bbryan; 06-30-2010 at 06:19 AM.

  2. #2
    Senior Member jtpitkin06's Avatar
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    Default Re: Kitfox engines

    In the early years the Kitfox was only available with a 2 stroke and it built a great reputation. The 582’s run fine. They are reliable and light weight. They are a great match for the early light weight airplanes like the Model 3.

    It’s time to get over the 2 cycle phobia. There are a thousand aircraft flying with two strokes and you don’t hear about them dead stick landing in schoolyards on the nightly news.

    Many naysayers point to the short TBO for the two strokes but fail to mention how cheap and easy it is to overhaul. Even if you fly a couple of hundred hours a year, it’s only about ones day’s maintenance to overhaul. A top end takes about three hours and it won’t dent your wallet like doing a top on a 912.

    When you break it down in cost per hour, you’ll find the two stroke is an economical powerplant. I’d put the engine on the airframe and go have some fun flying.



    John Pitkin
    Greenville, Texas

  3. #3

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    Default Re: Kitfox engines

    Thanks for the encouragement on the 2 strokes. I tend to think if the fuel delivery system is top notch they are all right. Seems like folks are always having fuel issues or at least thats the way it goes on my weed eaters and chainsaws. Of course those carbs are junk. Anybody using any kind of electric boost pump as a back-up.

  4. #4
    Senior Member HighWing's Avatar
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    Default Re: Kitfox engines

    I totally agree with John. Keep in mind, I have never owned a two stroke powered airplane, but I have flown alongside some in some pretty rugged terrain without so much as a burp from them. A couple of things I do recall, though. At most fuel stops and other stops as well, the cowl came off as the oil needed checking and possibly topped up. Another is that the 582 powered airplanes had a bigger challenge climbing to get over the mountains. That's about it. Their cruise was adequate to keep a flight of six or eight together.

    I am curious how trying something no one has ever done before seems less risky than following in the footsteps of hundreds of successful installations with absolutely tons of information and help resources out there. There are definitely other engine options, though - most heavier than the 582, but that is a topic for another day

    Lowell.

  5. #5

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    Default Re: Kitfox engines

    I never said I was normal. I do agree with you Hiwing, I should stay with whats true and tried, but I have a bad habit of always thinking outside the box. Not always a good thing for me as my garage of misfit toys reminds me of. I am improving however, I have move out of the solar powered round house and trying to look normal. Thanks for the feedback.

  6. #6
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    Default Re: Kitfox engines

    I bought a KF-IV with an HKS-700e four stroke engine.
    Partially because of "twostrokophobia", partially because of the lower fuel consumption and therefore extended range.
    The ideal would have been a Rotax 912, but that was outside my price range.

    These pages were one of factors that helped me decide:

    http://www.uflyit.com/hks_rotax_cost.htm
    http://www.greenskyadventures.com/En...ostCompare.htm

    Please take note of the following:
    (a) The HKS TBO has been extended from 800 to 1000 hours since these web pages were made.
    (b) Both the persons that made the price comparisons above and myself can be suspected of some partiality - I own one of these engines, they sell them.

    Roberto Waltman

  7. #7

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    Default Re: Kitfox engines

    I'm don't agree about the cost and reliability of the 582.

    I flew mine for 200 hours and had it dialed in well. It had a HACMan on it and I could keep the EGT's just where I wanted them. It could pull the KFIII past Vne (100mph) in level flight and a couple of times when I was in a hurry to get back before dark it pulled me along at 95mph. It would climb with me and my instructor (GROSS weight) at over 600fpm. Fast cruise at 85mph burned close to 6 gallons per hour. Pull it back to 60mph and it was about 3. At 12.5K feet (with just me in it) it was still climbing over 300fpm. It did perform very well.

    However, the cost to run it is high. First off, if you have an older grey head, pull off the carbs and look into the bottom end of the engine. Rotate the motor and look at the connecting rods. If they are machined and shiney you have the newer crankshaft assembly. If they are rough cast on the outside they are the smaller journals (besides being at least 15 years old) and its up to you if you want to run with that assembly. I elected to change mine out.

    Next is although they are not hard to work on, every darn gasket and o-ring costs a fortune. I know where you can get a lot of this aftermarket and save some money but still.

    I was forever having to burp that oil line as it tended to collect a big bubble in it. No leak, but the line didn't go up-hill the whole way to the oil tank. I changed out the injector pump(many people toss them so they are cheap) without fixing the problem. I changed out the small injector lines but that wasn't it either. More of an annoyance but it was a preflight item.

    I had trouble running 100LL. Others have done it w/o problems but I know I'm not alone. I got back from a long cross country with the engine not making full power. Turns out it was fouled with lead. The piston tops, cylinder heads, plugs, exhaust system, etc. all looked like they had been powder coated white. The rings were stuck and cylinder walls scratched. When I called South Mississippi and started to describe the problem, the guy said, "Let me guess; the inside of you motor looks like its painted white." Yep. So the next size up on pistons, honed cylinders and the engine ran fine again. No, I wasn't using a lead scavenger because normally I run car gas at home.

    If you are willing to work on the motor and keep right on top of it then it should be reliable enough.

    If you put enough hours on the motor you will have paid for a 912. I'm installing an HKS which is even cheaper to run. It won't have to same performance as the 582 but close enough for the flying I like to do.

    FWIW,

    Mark

  8. #8
    Super Moderator Av8r3400's Avatar
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    Default Re: Kitfox engines

    If you keep your eyes & ears open and talk to people you will find many used 912 engines for a lot less than new prices. They are out there but you need to dig. I just heard about a low time 80 hp takeout that was sold not far from me for $5k.

    To all the guys running 582s and 503s more power to you. But, I will not fly behind (or in front of) a 2-stroke.
    Av8r3400
    Kitfox Model IV
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  9. #9

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    Default Re: Kitfox engines

    The gasket sets on ebay are marked up 100%.

    Try
    http://www.mfgsupply.com/m/c/711194.html

    I used these. Also a link there to just a top end set if thats all you need. I didn't use the crankshaft end seals as the Rotax ones are higher quality. The rest are fine. There are a couple of waterpump spacers you'll still need from Rotax but this $50 kit will save at least $100.

    BTW C5, your trip report was awesome. I did some flying around the north Georgia and North Carolina mountains but nothing in comparison to your trip. That was with the 582 and it always scared me silly looking around for a place to land and finding nothing. Beautiful but frightening.

  10. #10

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    Default Re: Kitfox engines

    Hi Fellow KF's,
    I looked into the intake port and it appears the connecting rods are a different color and they look cast, not machined shiny. What a shame, as this engine has "Never" been removed from the box. Wounder what the complete engine package is worth new in the box. Maybe I could sell and get an HKS or something. I may have to use this engine for a while because of finances. I wanted to stay with the lightweight of the 582 because the KF is suppose to end up on floats. I have a mental issue with the 2 strokes that may spoil my flying as I will always be looking for an emergency landing spot and scanning the instrument panel looking for problems rather than enjoying the flight experience.

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