Harley engine on a sport plane

[hotrodrainey]

I want to put a 95 cubic inch Twin cam Harley engine on a sport plane such as the Sky Raider or Kit
Fox etc. Would like to buy a used plane minus engine. Any advise or suggestions welcome

[FlyingRon]

You'll need to find something that can take an engine. The problem is the thing puts out what 70HP at 140 pounds of dry weight. That's about twice as heavy as most of the engines typically put in a homebuilt.

[Aaron Novak]

You'll need to find something that can take an engine. The problem is the thing puts out what 70HP at 140 pounds of dry weight. That's about twice as heavy as most of the engines typically put in a homebuilt.

Oooooh the Hardly Ableson II .........I like it :)

In all seriousness......I have to ask why one would pick one of the worst engine designs out there for an aircraft engine???? Power is going to be close to 70 ( probably closer to 60 ) if you expect any kind of durability, they vibe levels are going to be horrific ( yes even the balanced one ) etc etc. The crank design has some severe torsional issues if you add a whole lot of mass to it ( i.e. direct drive ). Like I said.....im curious as to why???

[WLIU]

Didn't Steve Whitman try that idea? I seem to recall a magazine article where the Harley powered engine was dubbed the "Barely Ableson".

Perhaps one of the current generation Prop Speed Reduction units could isolate the engine from the prop. And there are racing Harley parts that might take care of the engine's mechanical issues.

Best of luck,

Wes
N78PS

[FlyingRon]

But I bet it would sound really cool!

[Aaron Novak]

Wes,
It was the Hardly Ableson. The flaws as I see them in the harley engine are not specific to the actual components, but to the overall design. Heat rejection from the heads will be marginal, the roller bearing built up crankshaft I see having issues.

[Bill Greenwood]

"YOU MEET THE NICEST PEOPLE ON A HONDA" was the slogan for years.
But if you are bored with the nicest people, maybe a Harley will help you meet some of the others.
Course if you really want to race or ride cross country touring,there are better bikes than the old 2 cylinder shaker.
A cycle magazine did a recent test ride on an old vintage H D 750 road racer probably circa 1969 . It had good power but was so rough that the rider described the feel as like "two giant hammers beating on the same anvil".
By the way if you like motorcycle racing , look up the history of Cal Rayborn. He was a young guy from San Diego who was a factory rider for Harley and won Daytona in 1968 and 1969, at a time when the Japanese bikes were starting to take over, he could compete due to sheer riding skill. He even went to England with a private race bike and won 3 of 6 races against elite riders there.

[58boner]

New guy posts and gets beat up by the elitist bully pulpit. Nice job guys.

[martymayes]

I want to put a 95 cubic inch Twin cam Harley engine on a sport plane such as the Sky Raider or Kit
Fox etc. Would like to buy a used plane minus engine. Any advise or suggestions welcome

There was a company called "Hog Air" that developed a V-Twin (Harley based) engine for sport airplanes. They installed one on a Zenith 600 series. You can see it on this you tube video:

http://www.youtube.com/watch?v=LSTRlAx_YSc

The company is now operating under the name of "Sky Ray" http://www.skyray.us/index.htm . Click on the video section if you want to see it in action. The rumor I heard was H.D. had legal send all kind of threat letters for any use or reference to harley, hog, etc.

I think it's pretty cool and it sounds great!

[Aaron Novak]

New guy posts and gets beat up by the elitist bully pulpit. Nice job guys.

No Bullying here. I just happen to work with a bunch of guys that used to be at Harley engineering before they closed down most of their engineering facility. We talk daily about the issues and design shortfalls of things when taken outside the scope of their original design. I myself used to work on these engines.....and so armed with my personal experiences, and the knowledge of my co-workers that were in Harleys engine design group....I feel justified in asking why the heck you would want to do this?

[FlyingRon]

No bullying....Thought about why I hadn't heard of it being done (other than my personal ideas of V-twin reliability). I was liberal in my estimation of HP (high) and dry weight (low) and figured out a big part of the reason. It's more than twice as heavy as a ROTAX 582 before you even put the redrive on it.
My comment was you have to find an airframe that can take that much weight and fly with that little HP.

[Andrew King]

Look no further than Oshkosh Pioneer Field:
http://www.airport-data.com/images/aircraft/large/000/713/713222.jpg

[Mike Switzer]

And it has a drip pan under the engine. :D

A while back I read about someone making a radial out of Harley parts. Personally, If I was going to use a bike engine I'd use a BMW, they are a whole lot smoother.

[Aaron Novak]

And it has a drip pan under the engine. :D

A while back I read about someone making a radial out of Harley parts. Personally, If I was going to use a bike engine I'd use a BMW, they are a whole lot smoother.

You would think one could find a LOT better design cylinder to make a radial out of. At least BMW would have aviation heritage, the closest a harley ever came to being a decent flyer was being rolled out of the back of a military transport in WWII.

[gbrasch]

May I suggest the 106 CI Victory engine? I am an old Harley rider who switched to Victory like many Victory riders. Do some research, the Victory engine is superior in many ways and I believe would be a safer engine for you. Just my 2 cents... Hope this helps.

[Bob Dingley]

This gentleman from Germany seems to be having some success with a BMW 1200. I believe that he is now in the US. This is his web site:

http://www.spang-air.de/e/html/bmw_-_engine.html

[martymayes]

At least one BD5 has flown with a BMW engine....check the SA archives.

[crusty old aviator]

So that's what happened to AirHog! Harley went corporate on them, like McDonalds does to any entity that calls itself McWhatever. It's not cheap, but the BMW would be a better choice, IMHO.

The converted Model A engine in the front of the Pietenpol Air Camper put out 40 HP and weighed around 250 pounds, so don't let weight stop you, provided you're okay with doing the engineering calculations to confirm the existing structure can handle that much weight up front. You may have to move the wing forward or ballast the tail.

[Aaron Novak]

So that's what happened to AirHog! Harley went corporate on them, like McDonalds does to any entity that calls itself McWhatever. It's not cheap, but the BMW would be a better choice, IMHO.

The converted Model A engine in the front of the Pietenpol Air Camper put out 40 HP and weighed around 250 pounds, so don't let weight stop you, provided you're okay with doing the engineering calculations to confirm the existing structure can handle that much weight up front. You may have to move the wing forward or ballast the tail.

Id trust a correctly overhauled "A" engine over a Harley twin-cam any day...........

[Victor Bravo]

The way I see it, the vibration is the primary issue, regardless of whether the engine itself is good or bad. I have zero experience with Harley engines, so I have to stay out of that part of the discussion.

A welded 4130 steel tube fuselage and properly dampened engine mount could probably handle the vibrations of a BALANCED and properly mounted Harley. A minimal, light gauge, pull-riveted, sheet metal fuselage like a Zenith probably would not be able to deal with that kind of vibration for very long. Rivet holes would start to loosen, new cracks would develop in the corners, any minor cracks would immediately get worse, the aluminum would start to harden and get brittle, etc.

The "Mini-Me" version of the Harley V-twin, the Briggs & Stratton 22HP Vanguard, is now successfully flying on a few small single seat designs. I believe the vibration on those is manageable, have not heard of any fuselage structure problems yet. But these have a lot less rotating and vibrating mass.

[rwanttaja]

The way I see it...
If this is who I think it is: Great to see you're still around, Bill.....

Ron Wanttaja

[hogheadv2]

Modern Harley engines are outstanding for reliability, most unmolested motors I have seen are over 100,000 miles before the top end / piston and rings are done. [These are not throttle rod bar jockey's] Harleys ARE Built With a chain drive speed reducer! Belt drives are a rage of after market and Race machines as far back as the 60's. With any aircraft repurpose engine a tear down and inspection is mandatory. Set up timely inspections for certain wear parts, ( maybe use gear drive cams to eliminate the timing chain) Cruise at 3200-3400 rpm all day long - every day.... at 100+ lb ft of tq at your crank, x 1.4 bdsr = 140 lbft , 75 hp at about 2800 prop rpm. Good baffling around the cooling fins, wrap the pipes in glass tape, (may want to relocate the carb to prevent icing [ airbox near the exhaust tube] http://www.aeroconversions.com/products/aerocarb/index.html This aerovee unit may be a replacement for your carb, unless your going HD fuel inj. If you look close a HD engine appears to be but just 2 cylinders of a Radial aircraft engine ;)

[Victor Bravo]

If this is who I think it is: Great to see you're still around, Bill.....

Ron Wanttaja

Wow... if you're remembering me all the way from those ancient days on RAH, thanks for the shout-out. Glad to see we're both still around :)

[Aaron Novak]

Modern Harley engines are outstanding for reliability, most unmolested motors I have seen are over 100,000 miles before the top end / piston and rings are done. [These are not throttle rod bar jockey's] Harleys ARE Built With a chain drive speed reducer! Belt drives are a rage of after market and Race machines as far back as the 60's. With any aircraft repurpose engine a tear down and inspection is mandatory. Set up timely inspections for certain wear parts, ( maybe use gear drive cams to eliminate the timing chain) Cruise at 3200-3400 rpm all day long - every day.... at 100+ lb ft of tq at your crank, x 1.4 bdsr = 140 lbft , 75 hp at about 2800 prop rpm. Good baffling around the cooling fins, wrap the pipes in glass tape, (may want to relocate the carb to prevent icing [ airbox near the exhaust tube] http://www.aeroconversions.com/products/aerocarb/index.html This aerovee unit may be a replacement for your carb, unless your going HD fuel inj. If you look close a HD engine appears to be but just 2 cylinders of a Radial aircraft engine ;)

If you look even closer, it is nothing like an aircraft radial at all. Keep in mind a motorcycle duty cycle and aircraft duty cycle are completely different. A typical full dress harley will use about 18 horse to cruise at 65mph. The knife and fork roller bearing connecting rod system in a weak link, and tapered pin crank does some downright scary things.

[hogheadv2]

Why I continue to try to educate people.... The Twin cam uses a pressed round pin, That can easily be welded to the flywheels after they are set and balanced. Out of the Thousands of bikes and bikers I have associated with, I have never observed a properly set of flywheels move once set up. [improperly and too many 12 packs worked on them, a couple] ....... A Harley with rider has far worse aerodynamics than a brick! Go look it up. Touring bike 2 up with a trailer runs the hi-way hours on end, thousands of miles, year after year.... Far more load at cruise than a LSA.

[Aaron Novak]

Why I continue to try to educate people.... The Twin cam uses a pressed round pin, That can easily be welded to the flywheels after they are set and balanced. Out of the Thousands of bikes and bikers I have associated with, I have never observed a properly set of flywheels move once set up. [improperly and too many 12 packs worked on them, a couple] ....... A Harley with rider has far worse aerodynamics than a brick! Go look it up. Touring bike 2 up with a trailer runs the hi-way hours on end, thousands of miles, year after year.... Far more load at cruise than a LSA.

You are right, I was thinking of the pre TC cranks before the cost reduction of the pressed pin type. I always felt welding the cranks was a poor idea due to the carbon content of the parts and the relaxation of the press caused by heating. I just couldnt do it, I work with too many guys that worked in harleys engineering dept durring the TC "development" to ever feel comfortable flying behind one.