Ridgerunner IV with aerovee 80 hp

[smartguy 17]

https://marshall.craigslist.org/avo/d/milroy-ridgerunner-iv/6832753953.html

[Allen Sutphin 705]

I was just about ready to buy a Ridgerunner Kit before I found this model 2. Being a hillbilly, I had some thoughts about sending a big check to somebody I had never heard of. Turns out he was OK. I bought a couple of tanks from him. Still like the Ridgerunner, though. And that's a good price on one, don't know about the engine though. The Sonex seems to work well with that engine.

[Bandit 286]

I have talked to a guy that knows him.

 He has had trouble with cooling the engine. I think he has only test flew it. The build is real nice though, just not a good engine choice. 

[Allen Sutphin 705]

That is generally the issue with a VW conversion of various types. Keeping the cooling under control.  I know several who have tried the various VW engines and its always the cooling issue. Some were successful but many were not. It is an attractive engine at a reasonable price and parts are everywhere, which draws builders to it. A lot of R&D has been spent on VW engines with little success.

[TJay 1041]

Wonder why they don't just build cooling plenums like Jabiru does. I can barley get to operating head temps with my Setup.

[Allen Sutphin 705]

I am sure someone has tried several times. Maybe for the weight/horsepower ratio isn't good enough to spend the investment (time) on it. I am going to have to come up with a cooling system for the Hirth. A reverse flow fan is the solution, but nobody connected with Hirth wants to discuss it. Don't know if a 3-D printer could make a copy or not. I am not up on 3-D printers so I am clueless. I am thinking of trying to turn it around 180 Degrees with a couple of bushings to line up the fan belt. Designing a powerplant system (not the engine) is a head scratcher at best. A lot of variables in the mix.

[wypaul 448]

I didn't have cooling issues with the Revmaster I had in my Q2.  I built cooling plenums as T Jay mentioned and built a plenum for the oil cooler also.  The big problem with the VW's is the weight to HP ratio.  65 horse weighted 200 lbs with the light weight starter. The Jabiru 3300 that I put in its place weighs under 180 and puts out an honest 100 HP rated at 120.  I would not even think of putting another VW in an airplane.  Well maybe in a bomb bay for dummy bombing practice  

[Av8r3400 1177]

The people who seem have the only luck with VW engines are the ones turning a small diameter prop, at high rpm and going relatively fast.  Sonex, KR2, etc.

[wypaul 448]

You are right about that Larry the Q2 ran a 54" inch prop and flew 160mph but even with flavored lipstick it still was a pig.  A fast one but... with the Jabiru it will do 200 and cruises at 175 mph.