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Thread: McCullich 0-100 on Avid C?

  1. #11
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    Default Re: McCullich 0-100 on Avid C?

    HIGH COUNTRY:

    You mentioned wanting a low cost 4-stroke. If you have the Kitfox model 3 or 4, Great Planes VW makes a firewall forwared kit for the Kitfox (That's what I am installing on my plane) . Below is data from a previous thread:

    This was the original post, and since then one of the members of our forum flew in it a few months back and thought these performance numbers were basically correct with respect to rate of climb and cruise speed (though he didn't weight it). Note: it does have the speed wing mods and vortex generators, it is also a tri-gear with spring gear, so my plane will be setup almost exactly the same as this one as mine has already been converted to Tri-gear (but will run the larger 2300cc engine on car gas)
    Here is the post:
    Ok, I finally was able to get the performance numbers off a flying Kitfox-4-1200 with a 2180 Great Plains VW motor installed, it‘s the one in St. Louis, currently listed on Barnstormers.
    The great thing about this plane is it’s a known quantity. As VW aero engines can be anything from a 1600 cc 45HP engines to a 2300cc 100+ HP monsters (with water cooled heads), this engine has been identified as a 76 HP Great Plains 2180 cc engine turning a Sterba 62x32 prop at 3000 rpm in cruise. This engine requires Avgas at this HP rating and develops peak power at about 3500-3600 rpm, but typically cruises at 3200 rpm, which is close to where the peak torque is created.

    N53RJ KitFox IV Speedster

    Weights:
    Basic Empty Weight = 700lbs
    Max Weight = 1200lbs
    Usefull Load = 500lbs
    Fuel Capacity = 27 Gallons
    Wing span = 28.8 ft.
    Fuel Burn = 4 - 4.5 Gallons an hour
    Cruise speed (economy setting) = 90 to 95 mph at 1500 feet (3000 rpm).
    Cruise speed (high setting ) = 110 mph at 7500 msl.
    Max speed (At full power) = 115 mph at 7500 msl.
    Rate of Climb (two people) = 700 fpm
    Rate of Climb (One ) = 1000 fpm
    Take off roll at Gross Wt = 300 feet
    Landing roll at Gross Wt = 300 feet
    Stall speed (with vortex) = 37 mph
    Approach speed = 60 mph

    Final note, I think the cruise speed could be improved with a prop diameter 2 inches smaller, though the rate of climb maybe negatively affected (or not). I would call the rate of climb good for a small cheap plane, better than the cessna 152 I flew at gross weight !!!!

    Roger




  2. #12
    Super Moderator Av8r3400's Avatar
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    Default Re: McCullich 0-100 on Avid C?

    Oh boy, here we go again with the vw bs.

    Poor performance, heavy, unreliable. The trifecta of everything you don't want in an airplane power source.
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  3. #13

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    Angry Re: McCullich 0-100 on Avid C?

    Oh boy, here we go with the knock anyone that likes anything but Rotax BS! These are experimental airplanes and a person is free to install any engine he or she wants. I get sick and tired of seeing members post negatively towards anyone that isn't on the Rotax bandwagon as if that is the only engine that gives a Kitfox respectability.

  4. #14

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    Default Re: McCullich 0-100 on Avid C?

    well its not the "knock" rotax thing. I am working on a rotax alternative that will make this plane a beast of performer. The issue is there have been many who have tried the VW.. perhaps on a gear box (making it even heavier) it would perform alot better. Swinging a small prop direct drive on these draggy planes just does not give them the performance that a geared engine does. It is that simple. I would LOVE to be able to yard the engine out of my sand rail and slap in in the nose and still have the performance that I have with the 582 (or even a choke, spit cough 912) but it simply is NOT reality. I could care less if you put a 500 HP chevy V8 in the nose, if it would perform the way a rotax makes it perform I would be all for it.

    The next thing to think about.... If the VW worked SO GREAT in these planes, dont you think that we would ALL BE USING IT??? Who in their right mind would shell out 20+ grand for a 912 when they could have the same performance, and reliability with a 5000.00 package???

    That being said, if you can show me that you have a 4 stroke that will rival the performance and reliability of the 912 for half the cost, I will be the first to buy it and slap it on the nose.

    all this of course, is indeed just my opinion, sprinkled with a generous dose of common sense (which is not always common).

  5. #15

    Default Re: McCullich 0-100 on Avid C?

    Ok so after somemore research im starting to think this is a model B with some of the model IV parts. i have nothing against the rotax engines i had the 447 in my sky raider with almost 450 hrs on it when we sold it and it flew great and had never been overhauled, just changed the plugs and gearbox oil. im mostly wanting to go to a 4 stroke for the sake giving me more time between overhauls (less maintance) i have a good lead on a local subaru ea 81 and an ej 2.2 for under 400.00 complete running with less that 100,000 miles on them, what are your thoughts on rebuilding/converting one of these and making it a turbo? good idea, bad idea, why?
    Thanks for all the input

  6. #16
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    Default Re: McCullich 0-100 on Avid C?

    Snakeoil salesman & others;

    I think if you look at the performance numbers shown on this flying VW kitfox (as listed below), it's obvious that the VW direct drive engine is not as good as a 912S or even the Rotax 912 80HP. It weighs more and has less power. However, having said that, it does (in my opinion anyway) provide a good combination of climb and cruise performance for the money, which might (or might not) be deemed “good enough” for some kitfox builders on a very “limited” Engine/Prop budget , just like me. ( used VW engines go for as little as 2-3K, and can be rebuilt for about $500)

    For me, the VW direct drive will be good enough, but then again I don't need a super high rate of climb like the 912S can provide. Perhaps others might be in the same boat too. I say, look at the performance numbers and let each person decide for themselves; is the VW installation good enough for me.
    Roger

  7. #17
    Super Moderator Av8r3400's Avatar
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    Default Re: McCullich 0-100 on Avid C?

    With a B model Avid, weight is a major concern on the nose. Keep in mind that Avids were designed around a 50-75# two stroke.

    Subaru conversions are usually north of 250# installed. However, there have been many Subbies installed in Avids over the years. The common feature in them all is they all require copious amounts of lead in the tail to make them balance.

    I have a friend who had a Subbie in a IV Kitfox (much more tolerant of heavier engines than the Avids). His plane had two batteries and lead in the tail to balance it. All of the ballast made it, basically, a single seat airplane.
    Av8r3400
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  8. #18
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    Default Re: McCullich 0-100 on Avid C?

    The Subaru EJ 2.2 is a was a popular engine for the Zenith 601 HDS (gross weight 1200 lbs) that I had and flew for a while (with a VW), and I looked into it as a power option. It produced great power for great cruise speeds (for all those speed demons out there), but it WAS heavy. Installed weights of 270 lbs were typical, but the airframe could take the power and weight with little modification (HD means Heavy Duty in the 601 HDS) and it was sort of cheapish, thus it was a popular engine choice for a long time. Note: Stall and landing speed were high though, the plane flew much better with a 912 (but the 582 was too small).

    I don’t know too much about the smaller EA-81 (which I heard produces 95-100 HP at the drive shaft, but much less at the output of the redrive) It weighs less and has been a popular choice over the years with smaller planes. It might be better suited weight wise for the Kitfox/Avids than the EJ 2.2, but I think most folks believe it’s still too heavy an install to be practical ( more than 200 lbs with redrive and prop, I think).

    FYI, the direct drive VW, as mentioned before, has a typical install weight of about 180 lbs (with wood prop), but you can knock 10 lbs off that with the aluminum cylinder option.

    Hope this helps
    Roger

  9. #19

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    Default Re: McCullich 0-100 on Avid C?

    Suppose we take the weight and performance off the table for a minute and just consider reliability. How does the VW actually stack up compared to Rotax? I'm looking for actual stats, not just the usual anecdotal stuff. I realize the sample size for VW is small, but they are out there and have been for a long time. I suspect reliability is the actual reason we see so few VW powered aircraft.

    I'll admit to knowing nothing about the VW aircraft conversions, but as a teenager growing up in the 70's I had plenty of VW car experience. I've owned two buses, two beetles, a squareback and a notchback. In a few of these cars I put together hot-rodded engines and will say that you can squeeze a lot more than the stock HP out of em, but you start pushing up against the design limits. I think the reverse is true with a 360 cubic inch Lycoming putting out 180 horsepower. Regarding the Rotax, I've never even seen the outside of one, let alone the guts.

  10. #20
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    Default Re: McCullich 0-100 on Avid C?

    Steve;

    When you buy a Rotax, it comes from the Rotax factory. You know what you are getting. VW aero conversions have been around since (what before WW II ?), well for a very long time. Unless you are a VW aero conversion expert, you don’t know what you have or how reliable it will be. For that reason, I recommend only buying VW aero-conversions from one of the top 3 makers: AeroVee , Great Plains VW and Revmaster. With these, you get decades of experience and engines with well known strengths ( and some weakness, that must be addressed). These engines are very reliable when installed and operated correctly, but as reliable as a Rotax 912? Well, probably not (though some might argue otherwise).

    VW conversions are simple 4-stroke engines, built with specially made aircraft components (such as forged cranks) and are very much a known quantity if you buy from one of the 3 main builders. Buy something from “Bill Bobs swap buggy shack”, well, who knows what you will get and how reliable it will be. If you want real reliability numbers, I have not seen any figures specific to the 3 main builders engines, but they are installed in a LOT of small aircraft (4 at my local airport alone), and not all of these planes are fast walkers, some are slow (slower than the kitfox model 2 !!!!).

    Hope this helps
    Roger

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