Av8r3400

I have an opportunity every year of being involve at the AirVenture UL area.  I’ve seen many of these alternative engines in person.  I see which ones fly and which ones do not.  The last Hog-Air powered plane I saw there was a Pietenpal.  These fly reasonably well with a 40 hp model T or a 75 hp Corvair engine.  With the HD engine it was barely operable on the field.  The next year the plane came back with a Corvair. 

It was first flown a couple of times a year ago then abandoned.  I’d bet because it is seriously underpowered.  It was flown, found to be a complete dog, now being dumped for a fraction of what a good flying plane would get.

I dont buy the comment that after building this plane he all of a sudden decided he needed a twin. 

Ive seen this now a couple of times. Where is this coming from because it is not true.  Rotax still makes the 582 and fully supports it.  They stopped 503 production several years ago, parts can be a challenge, but can be found. 

I've seen several Kitfox 1 airframes successfully fitted with the 912UL engine.

Wingtanks.com is Airdale Sportplane and Supply.  Good luck.

They are roto-molded polyethylene.

We will only sell these engines to qualified Race Teams with solid budgets large enough to support extensive development necessary for top level racing

This quote from the website tells you everything you need to know on this engine.  It is a race engine.  It is designed for maximum performance output, not longevity.  Definitely not something that I would fly behind even if the company would sell you one.

The V-Rod engine like most other ATV and Motorcycle engines are integrated with a transmission.  This eliminates them for aviation conversion.

I see why it's only flown a couple of times.  That motor will not make enough power to go anywhere with that plane.

I showed a bottom out last night of -30F.  Wind chill was close to -60F.

Wouldn't be my first choice to trust anybody's life with, a 80 year old two-stroke, with no parts availability, designed to fly a gunnery target - ONCE.

I'd be willing to bet you have an alignment issue.  The larger, softer, smooth tires are allowing more slippage which masks the problem.

The photo with the 21x800/6 tires on the plane even looks like it has quite a bit of tow out.  With the geometry of that gear, as it moves through it's travel it will make it worse.

I used one of these on my first plane and again on the Mangy when I re-did the firewall forward.

The coolant (DexCool) should be changed every 200 hours or so.  Over time the coolant gets more acidic as it reacts with the aluminum.  This slows to near zero the degradation of the block.

Wow.

I see the oil cooler on the belly and the coolant radiator on the front of the engine. 

The oil cooler can probably be completely taped over in the winter, or make a sheet metal cover that can be attached with a shutter on it.

Where is the coolant radiator getting it's airflow from?  The large cheek openings?  What about the baffling on the radiator? Is there a duct attached to it?

She's still a beauty, Randy!

Sounds like you have all the answers.  Build one and prove me wrong.

Having ridden Harleys for years, they don't make peak power in an RPM range that will swing a prop and the crank bearings won't support or bear the twisting of a prop either.  A reduction will be needed.  It will be heavy and will require much custom work to make it function.  At the end of the day you may get it to work but it won't perform as well as a 582 or even a 503.

We have seed the VW topic so many times...  The only few that work, even slightly well, are in speedy, small craft turning very small diameter (60" or less) propellers at higher RPM (3500-4000).   In the near 40 years of Avids and Kitfoxes, it has been proven time and again VWs DON'T work in these planes.  They perform terribly, have overheating issues and are far from reliable.

If you want a reliable engine without a reduction, get a C65 Continental.  The weight will be similar to a redrive VW and only a few pounds more than a redrive HD.

With all of the Apex and RX1 engines going into airplanes, there will eventually be someone come up with an adapter for the 2-cylinder versions in the Phazer and other smaller snowmobiles.  These motors would be another candidate to use. IMO better than a butchered VW engine.

The 600cc Rotax ACE motor has been around for several years now, too.  70-ish HP with fuel injection and all of the modern amenities.

I converted my IV-1050 from ATV wheels & bungee gear to Grove wheels, brakes and gear with real airplane tires (21x800-6) and the total weight gain was 12#. 

A very easy thing to accept for all the gains.

These are good points, Chris and I don't doubt your experience.  Damping and mass of the wheel itself are certainly factors to consider.

However, every single time I have encountered tail wheel shimmy on my plane and others, it was directly caused by (and solved by) adjusting the caster angle of the pivot axis.  My plane was shimmying badly during my trip out west.  The steel spring had sagged and was making for a negative caster angle.  On that trip I purchased a used Grove aluminum spring.  After installing the spring, all shimmy went away and as you can see, it has a positive caster angle.  During the spring installation I disassembled the entire assembly to check for wear and anything else I could find.  All was good and the swivel action is very free and loose.  The chains also have some slack in them.  No shimmy at all.

This photo has been around for a long time, but shows well the "Pivot Axis" everyone is talking about.

I have a 78x48" Prince on my model IV.  I think Mike Kraus has a Prince on his Rotec.  I don't know what size it is...

My exhaust is a Kitfox factory system.  It doesn't use ball and socket joints, that is the major flaw in it's design in my opinion.