McCullich 0-100 on Avid C?

[High Country]

My wife and I are about to start building an Avid C kit and we are looking to see if there are any changes we should make along the way seeing as this is such an old kit, i currently have a new Rotax 532 complete w gear box and prop but have been looking at other options i have the oppertunity to purchase a 0 time smoh McCullich 0-100 which is lighter and more power 72 hp for $600.00 is this a good option money is to tight to go to nice engines that everyone else is running so i thought this may be a good upgrade that we can afford. Are they reliable, how long on overhauls, are parts available, and reasonably priced?
Thanks
Robert

[akflyer]

While it may say its 72 HP, it is direct drive and swinging a little prop. You will not get the thrust out of it that you need for anything resembling STOL performance. I would be saving up for a good used 582 instead of messing with the Mac..

[rogerh12]

Robert;

I find your McCullich 0-100 engine option very interesting. I am not familiar with this engine, but it looks like it might do well in a smaller kitfox or the like. Although many folks think only a Rotax belongs in a Kitfox or Avid, folks have install other experimental engines and done pretty well, and for a fraction of the price of a new Rotax 912.

I personally would not install another 2-stroke in any plane I fly (but that’s just me), so the big plus for the engine is that it is a direct drive 4-stroke, making simple, rugged and fairly light (no re-drive required). However, the Kitfox type aircraft do better with engines capable of spinning a fairly large diameter prop, and my concern is prop selection for this engine would be limited. I think you are looking for at least a 60” prop, because of the largish frontal area of the kitfox and Avid. Also, parts might be a problem (do you know where you can get parts)?

[desertfox1]

The McCulloch 0-100 engine is a 2-Cycle engine built
for drone use. Designed as a 50 hour engine as it was
meant to be shot down. It has been used in gyrocopters
with some success.

[av8rps]

My wife and I are about to start building an Avid C kit and we are looking to see if there are any changes we should make along the way seeing as this is such an old kit, i currently have a new Rotax 532 complete w gear box and prop but have been looking at other options i have the oppertunity to purchase a 0 time smoh McCullich 0-100 which is lighter and more power 72 hp for $600.00 is this a good option money is to tight to go to nice engines that everyone else is running so i thought this may be a good upgrade that we can afford. Are they reliable, how long on overhauls, are parts available, and reasonably priced?
Thanks
Robert

Don't underestimate that little 532. I put 880 hours on a 532 without ever overhauling it, and it ran great the entire time. Plus, at 880 hours I lent it to a friend that was working on some mods for Rotax 2 strokes and used my engine for dyno testing before and after results, and found that little 532 dyon'd at 74 horsepower. He then dyno'd a 582 shortly after that and found it only did 62 horsepower. So the 532 makes power, runs good, and is a bargain for what it does for power. I wouldn't hesitate to use that engine, they are good engines. Might be worth putting a nippondenso ignition system on it so you don't have to screw around with point adjustments (which you normally do once you have 25+ hours on motor, and then it is good for a long time). Also, fwiw, the Avid flown from France to the North Poloe in 1987 was powered by a 532 Rotax. So even though many will not get too excited about a 532 Rotax, they work well.

Paul S

[akflyer]

You care to point out where you gathered that lil tid bit of info from?? You must have found the only 4 stroke Mac ever made for drones..

[rogerh12]

We have one of these McCullich 0-100 here in our local Aviation Museum (in Topeka Kansas), it's where are EAA group meets on occasion. Here is the link with a picture of the display.

http://www.combatairmuseum.org/exhibits/mcculloch0-100-1.html

I was told before it was a 4-stroke, is that wrong?
(I must admit, I never really looked to close at it, we have a bunch of cooling things at this place, so maybe its' a 2-stroke, it kinda looks like one now that I see it again).

If you want a two-stroke on your plane, go ahead but I have not had good luck with them in general. I have had them quit on me before (not the Rotax, though the guy that I bought my model two had his seize in flight) but boats, motorcycles and other small engines. They general end up making me cuss.

Roger

[High Country]

Thanks for all the great imput, so we've decided to stay away from the mccullich so the question is do i use the 532 or change with something else, keeping in mind that finance is my biggest factor, where is a good place to purchase the nippondenso ignition system for the 532 and is there any other upgrades that will make it more reliable? I had the 447 on my skyraider and was very pleased with its performance for the lighter airplane. I would really like to go to a four stroke such as an 0-200 but the cost is a bit much, im a certified welder so building engine mounts etc is no problem for me if i can find an affordable 4 stroke.

[akflyer]

Lots of people have succesfully used the 532. I think rotax rick may do the conversion for you, or there are several other engine builders who will do it. You have to notch the crank etc when you install it so it takes a little bit of doing. Your engine choice should be based on your mission. Are looking for back country super STOL or more CC cruising around the country side just flying airport to airport?

[avidflyer]

Airscrew Performance in Arizona can do the electronic ignition change for you, he has been doing them for many, many years. Some benifits of sticking with the points ignition is it is real easy to hand prop for starting with the points setup. You have to spin it much faster with the CDI to make spark. Also, on single ignition, some feel that points are more dependable than CDI, if they are going bad, the engine might still run, just not as good as it should, but when CDI goes, it's gone. I had a 532 with points in my last B model Avid and it was just fine and made lots of power. Take care, Jim Chuk

[rogerh12]

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

[Av8r3400]

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.

[Woodennickle]

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.

[akflyer]

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).

[High Country]

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

[rogerh12]

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

[Av8r3400]

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.

[rogerh12]

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

[szicree]

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.

[rogerh12]

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

[av8rps]

Thanks for all the great imput, so we've decided to stay away from the mccullich so the question is do i use the 532 or change with something else, keeping in mind that finance is my biggest factor, where is a good place to purchase the nippondenso ignition system for the 532 and is there any other upgrades that will make it more reliable? I had the 447 on my skyraider and was very pleased with its performance for the lighter airplane. I would really like to go to a four stroke such as an 0-200 but the cost is a bit much, im a certified welder so building engine mounts etc is no problem for me if i can find an affordable 4 stroke.

I've been messing around with Avids and Kitfoxes now since 1987, and still own the first Avid ever built, powered by a 43 hp Cuyuna 2 stroke that was normally used in Scorpion snowmobiles. And even though only 43 hp, it flew very well, and enjoyed a solo rate of climb of nearly 1500 fpm. Of course it only weighed 360 lbs, so it just goes to prove how critical overall weight, and even more so engine weight, is on this aircraft design.

And for any of you that didn't know this, when Dean Wilson designed our airframe, he discovered that if he could eliminate 1 pound of weight from the engine, he could remove 2 lbs of weight from the airframe, and the aircraft would remain just as strong as a standard, more conventional aircraft. So engine weight matters a lot more in this design than with a more conventional aircraft.

So reverse that design feature by installing heavy engines, and you have totally defeated what the designer sought to create with his revolutionary concept. So remember, it isn't just performance that will suffer with a heavy engine, airframe strength will also be compromised.

That 532 can be used just fine as it came from the factory. Mine was bone stock and worked great for years. My other A-model Avid with the 532 weighs only 396 lbs and has a climb rate of over 2200 fpm, seriously! It is one hauling machine. So I don't think you could find a more effective (and fun) low cost option than the 532 for an Avid. But do everything you can to keep it light - that will make it a real hotrod. Modifications? You can easily live with the standard ignition points if you decide making it electronic is too much work. My 532 never had electronic ignition, nor did the one that went to the north pole. But I would recommend at least resealing an engine that has laid around for a bunch of years inactive. And at the same time, I would also recommend doing the upgrade (s) to the rotary valve seal and the water pump (I don't remember all the details so ask a Rotax engine guy).

Anyhow, the 532 is overall a great engine that worked very well on early Avids and Kitfoxes, and a lot were used. But it is still a two stroke and doesn't have the track record for reliability the 4 stroke Rotaxes enjoy.

However, like I always tell my friends that make jokes about friends flying 2 strokes "We should all fly everything like it has a two stroke up front, as any engine can quit". I've had 5 engine failures in aircraft in the past 30 years...2 were 2 strokes, and the other 3 were aircraft engines. So even 4 stroke reliability can be questioned...

[av8rps]

One last note, the only engine I have ever seen to work really well in the early Avid and Kitfox other than the 2 strokes or the 912 was....(drum roll.....) the small Continentals. I was always suspect that they could work well when you consider their weights, but a C-75 up to an C-90 or even an 0-200 will work, IF you do everything you can to minimize engine weight (like no electrics).

Done right you can put together an airplane that will weigh similar to the VW, but with significantly better performance. So, if you are insistent on using a 4 stroke, but want performance and reliability like the 912, but don't want to spend so much, find an old Continental, strip off any extra weight, bolt it in, and go flying.

[rogerh12]

The A-65's I hear are quite a bit lighter than the C-75, due to the lack of an electrical system. My buddy has one on his plane and of course he has to hand prop it (which does not bother him). Also, the parts are pretty cheap (by aircraft standards) and I think he said that his runs on car gas and it still produces 65 HP.

Anyone know the installed weight of a A-65?

Roger

[Woodennickle]

The 65 and 75 weigh the same the 75 prop may weigh a couple of pounds more. The engines are the same except for different pistons, different carb setting, and prop pitch so the 75 can turn higher rpm's. That is how it makes 75 instead of 65 is by higher rpm's.:rolleyes: