Anybody thought of using a B&S Vanguard (or similar lawn mower v-twin) in place of a (1/2) VW?

Could be an interesting option, but would likely require some structural mods to be on the safe side.

There's a pretty lengthy discussion on them on homebuiltairplanes.com. There are several threads on these engines. Here's one:

https://www.homebuiltairplanes.....is-q-a-thread.32382/

I've definitely been thinking about it.   I've also been looking at a lot of motorcycle engines and other things.  Surely there must be a 4 stroke, fuel injected modern engine somewhere that doesn't weigh a ton and makes 40ish horsepower..  Somewhere!

Yes, here....   http://www.culverprops.com/big-twin.php

"Also, we no longer make the Big Twin engine or any VW based engines.  We will continue to offer customer support for anyone who has a Back Yard Flyer or any of our engines, we are just not going to be in the manufacturing process anymore."

Aeromarine offers a v-twin that they claim puts out 60HP

https://www.aeromarine-lsa.com/vtwin/

I'm just curious about this... Just seems like a Max and a Vanguard would be a natural match, but I cannot find evidence of one having been built.

The magic bit on a Vangaurd/Genarac/Honda/Robin/etc... V-twin Lawn Mower engine is the PSRU. It's basically a wide belt, idler, and pulleys with a sprag clutch.

I wonder if the V-Max be a good match, or if the Max fuselage would need to be modified to allow this blue-collar aviation match-up?

I was looking up that aeromarine vtwin but it seems a tad heavy..  I saw some forum posts suggesting it weighs around over 110lbs installed weight.  That's a lil heavy, but maybe it doesn't matter?

Also a bit pricey.  I was looking around and the engine used in that can be had for around 2000 from some chinese manufacturer called gaokin.  So a lot of markup just for a redrive..

The thing is, I can get parts for the Briggs at Tractor Supply. Not sure you can do that with the AeroMarine or Gaokin.

Quoted from ITman496

I was looking up that aeromarine vtwin but it seems a tad heavy..  I saw some forum posts suggesting it weighs around over 110lbs installed weight.  That's a lil heavy, but maybe it doesn't matter?

It probably doesn't.  Compare to a Rotax 447 installed at 95 lbs you're looking at 15 lbs added.  Less than the difference between a 180 lb pilot and one weighing 200.

That's true.  I guess the max can handle quite a bit of weight up front.

Man that is an interesting deal.. I wonder how many HP it is.

The Valley Big Twins used a Generac (like the unit for sale) and advertised 40 hp. No idea if it was some other Generac though. Would have been nice of the guy to mention that.

I used to fly a Legal Eagle with the 990cc valley engineering generac conversion, it swung a 74x44 prop and had a terrificly short takeoff roll and climb rate (2 fuselage lengths and 1600fpm) but her cruise speed was dreadfully slow at 40mph and a max speed in level flight of about 52mph. fuel burn was 1.25gph though!

Chris

Hi
Anybody try Verner 3V? http://www.vernermotor.com/3VW.html
https://customsportaircraft.com/products/verner-radial-engines/verner-scarlett-3v/
Bob

996 Generac with one of these redrives  seems interesting.
https://www.aceaviation.co.uk/redrives

Quoted from ITman496

I've definitely been thinking about it.   I've also been looking at a lot of motorcycle engines and other things.  Surely there must be a 4 stroke, fuel injected modern engine somewhere that doesn't weigh a ton and makes 40ish horsepower..  Somewhere!

One motorcycle engine comes to mind but fixing the reduction drive could be tricky.If the engine could be had cheaply maybe one can do some sort of experiment.The engine is a dirt bike engine on a suzuki DR650.

Its 45 hp  air/oil cooled with a carburetor.I read somewhere it weighed 100-105 pounds.

It looks like a lot of weight could be taken off of it, too.

If you use a motorcycle engine do not use the gearbox. I know of at least one instance were the gear box failed.

Though imagine how fun it would be to row through the gears as you sped up for takeoff!  

Someone installed a suzuki GSX 1000cc bike engine on a gyroplane and flies it with the gearbox.https://youtu.be/HRZwFcNzgcE

Another person installed a chinese 650cc V twin engine direct drive on a heath parasol.This topic is being discussed on the Homebuiltairplane,com.

I wonder what pitch that block of wood counts as.  

Quoted from ITman496

I wonder what pitch that block of wood counts as.  

I was thinking the same thing. It appears to be both Flat and Feather at the same time.

Here's an option I'm considering. Would use a PRSU. 43hp at 4700 rpm for $2,995.00

https://www.performance670.com/product-detail/predatorperformance1

that thing looks sweet! I wonder how much it weighs with all the air ducting and cooling blowers taken off?

Quoted from ITman496

that thing looks sweet! I wonder how much it weighs with all the air ducting and cooling blowers taken off?

Watching this.
My concern is mainly around the thin shaft and lack of bearings, especially when power is double than originally designed.
I would consider driving the prop from the flywheel side.

Quoted from ITman496

that thing looks sweet! I wonder how much it weighs with all the air ducting and cooling blowers taken off?

Watching this.
My concern is mainly around the thin shaft and lack of bearings, especially when power is double than originally designed.
I would consider driving the prop from the flywheel side.

Hi
Use a re-drive like Culver props did.

Quoted from Bob Hoskins

Hi
Use a re-drive like Culver props did.

Aceaviation.co.uk make reduction drives for these V twin engines. Dont know if it works in a similiar fashion as the culver props reduction.Two plates are installed on prop shaft behind prop pulley.There are 6 matching circular depressions on the two plate inner faces about 1/2 way in from the circumference.Rubber balls resting in the depressions are sandwiched tightly between the plates by the large rear nut on thre prop shaft.Front plate has an ear on which idler pulley is installed which butts against the outer surface of belt on slack side.There is smaller tab on rear plate which during setup is used as a lever to turn the plate so putting sideways pressure on the rubber balls which in turn turn the front plate to put pressure on the idler pulley which tensions the belt..The rear prop shaft nut is then tightened.Between the power pulses when the engine slows down and prop tries to turn the crank the slack side belt riding on the rubber ball cushioned idler
pulley relaxes and the prop inertia can not drive the crank.With half the reaction gone there can be no torsional vibration.Gene smith explained it very nicely in one of his interviews.