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Thread: Kitfox 4 - VW power video's

  1. #1
    Senior Member
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    Jan 2011
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    LAWRENCE, KS
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    Default Kitfox 4 - VW power video's

    Looking for a good low cost engine options for your Kitfox?
    This might be it (VW powered):

    Watch it climb:
    http://www.youtube.com/watch?v=nRWzKMYz9eA


    It sounds sweet -> http://www.youtube.com/watch?v=v5x-ifHEi0g

    Sort of an explination about the VW Kitfox:
    http://www.youtube.com/watch?v=ficAq...eature=related

    It's been pointed out that because the VW engine requires the larger cowling, and has a limited diameter, it can't be all that fast. I agree with this myself, and am trying to verify the typical cruise speed of a Kitfox-4-1200 with the 2180 engine (note; a 2300 cc engine with aluminum cylinders is now available too).

    In the mean time, I believe it to be about 100 mph at 3000 ft msl, based mostly on hearsay, guess work what the guy at the psychic hotline told me (Also Great Plains VW). Is that fast enough ???? Shoot; my Kitfox 2 with a 582 would only cruise at an honest 75 mph, so 100 sounds awful fast to me !!!!!

    Really, my concern is the rate of climb, and obstacles, 50 feet in elevation at the end of a short runway, cruise speed is secondary.

    I am looking at installing a 2300 cc VW engine with low compression (7.5:1) so that I can run car gas. It should produce about 75 HP at 3500 rpm, which I think might drive a somewhat faired Kitfox-4 at 100 mph, but like I said, I am trying to verify this with some other flying planes .

    Agree?

    Roger

  2. #2

    Join Date
    Jun 2011
    Location
    West Columbia, SC
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    Default Re: Kitfox 4 - VW power video's

    Thanks for this. Sent a PM. I suspect at least some of the commentary about engine choice is loyalty to an engine choice already made. But the direct drive VW makes for some interesting issues. The higher RPM means a prop limited to 62" max. Purchase price and OH cost are both lower than the 912. Total installed engine weight will be a little higher for the VW. I think the VW looks and functions more like bigger aircraft engines I have used, than the 912 I flew behind. With the right pitch, it seems like "acceptable" speed and climb rate are achievable on a Kitfox IV. But you can get more HP with less weight using the 912, and you can use an adjustable prop. You can also use an adjustable prop with a VW with gear reduction, but I expect that adds a little more weight. I want to fly under Sport Pilot rules so only a ground adjustable prop would be allowed. I am not sure if I would adjust on the ground much. Seems like the biggest advantage for me would be if I were able to climb with a shallow pitch, and then adjust steeper for more cruise speed, and that is not allowed under SP. The biggest issues for me are that it is a 4-stroke; fuel is easier; air cooled; good speed, range, and endurance with 28 gallons of fuel; direct drive; the wood prop looks cool; OH cost and difficulty low. As for reliability, as the Sham-Wow guy says "The Germans make good stuff." If it is a real aircraft conversion, maintained and used properly, it will be reliable. VW has made a lot of 4-stroke engines; and the mods for aircraft use include improved front bearing, improved oiling, and a crank built for a prop in front - among many other improvements.

    I guess what I am saying is that what may be "unacceptable" to some will be a big improvement and very acceptable to others. Based on my preferences I could say the 2-stroke Rotax engines would be unacceptable, but they seem to have been used by a lot of Kitfox builders over the years. You make your choice and pay your money.
    Last edited by DBVZ; 06-14-2011 at 07:58 PM.
    Dwight B. Van Zanen
    Maple Valley, WA and
    West Columbia, SC
    PP/ASEL/IA
    Avid Mk 4 Aerobat

  3. #3
    Senior Member
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    Jan 2011
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    LAWRENCE, KS
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    Default Re: Kitfox 4 - VW power video's

    Dwight;

    A few remarks:

    A VW conversion, even a new one from the big name makers (Aerovee, Revmaster .. ect), is still less than ½ the price of a rotax 912 install, or in some cases ¼, depending on if you are willing to accept a rebuilt engine. I think the total parts bill for a VW rebuild is still only about $600 bucks, with a TBO of around 1000 hours on the engine (though some say it’s more like 800 hours).

    A 62” diameter prop for a VW is a big prop, most have 54-58 inch props in service. My “Warnikee almost constant speed” had a diameter of only 54” !!! The key is to get the right pitch, then workout the diameter. Most VW prop makers can do this in there sleep anymore.

    Regarding Rotax vs VW engine total installed weight; My Zenith 601 HDS had a VW installed, and the plane weighted in about 30 pounds more than a 912 install. But I talked to another guy that has a VW installed in his RANS-6, and he said it only weights slightly more than the factories demo plane, with a rotax 912, for whatever that’s worth. I mean, there is no doubt the Rotax 912 is a fine engine, the Cadillac of experimental engines, but hey, do you really need a Cadillac? What if you want to fly cheap and are willing to accept something somewhat less? Perhaps the VW on the smaller Kitfox planes is that something less (but not TOO much less).

    As far as adjustable props go, I too had one on my Kitfox 2, and oh sure, I would have lovee one on my VW powered Zenith, but they do add extra weight, and VW props are very well known as far as required pitch for a particular flight envelope, so most people just order one off the shelf and fly just fine. No real need to have one custom sized, unless of course you are trying to maximize engine performance (but does the Kitfox really need extra performance?) Lot’s of choices too, and a used prop can be had for $150 or slightly more, in like new shape.

    You mentioned reliability, certainly the Rotax 912 leads the field in that, but when it comes to VW engine reliability, I just tell people that if you are a real mechanic and know what you are doing, ok then, go out and build a VW engine and go fly it. But for everyone else, buy a prebuilt one from Great plains, Aerovee or revmaster, because those guys are the true experts and know how to do it right. Even if you buy a new-ish used engine, go ahead and send it in for a rebuild by someone like Great Plains, it will only cost you a few bucks more and you will definitely know what you are flying behind, and that’s cheap insurance.

    Hope this helps

    Roger

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