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Volkswagon engine...

J

Jeromiemead

Member
What do we do when we wait for product development to occur, Think...and think to much.

Be gentle to me on this one. WWW.gpasc.com They have a 2276cc belt reduction drive engine, pencils out to 185lbs total weight with options and stuff for rv-12 install. Using Bing carbs and nikasil cylinders and a few other optiond they have. Motor is insurable and He has a steller reputaion for the product. Have flown and airplane or two with these motors. Motor appears to fit in the cowling. Battery will need to be moved out the "cargo" bay and moved back approx 2 feet (rough weight andbalance calc.). Turn key motor ready to install for under $9500.00. 105hp takeoff and 70 continous. Should outpull the 912 on takeoff, cruise will be (my guess) slightly less or equall. The 912 Van's is using should be 170lbs wet and running weight. Experience says the installed weight of the VW will be 200lbs (prop, cooling tin, "stuff").

Thoughts?
 
I have actually got a fair amount of experience with limbach on a Taiphun motorglider. Only problem is cost and parts cost/availability in the USA. Costs approx. $6000 more for the motor and parts take time to get. In Europe I think it would be the way to go..
 
Jeromiemead said:
Be gentle to me on this one. WWW.gpasc.com They have a 2276cc belt reduction drive engine, pencils out to 185lbs total weight with options and stuff for rv-12 install. Using Bing carbs and nikasil cylinders and a few other optiond they have.
Thoughts?
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I seriously considered this engine for my bi-plane. #1, to get the 100+ hp out of this engine, you must use the Holley 2-barrel carb. The Bing won't give this hp. The 2 things that changed my mind are the weight and the torque curve. The torque curve of this engine drops off dramatically below the "rated" RPM.
I decided to go with the Jabiru 3300 because of the lighter weight, more hp, direct drive, and very flat torque curve. The Jabiru is putting out 100 hp at below 2800 rpm.
 
Mel said:
I seriously considered this engine for my bi-plane. The torque curve of this engine drops off dramatically below the "rated" RPM.
Click to expand...

Mel, I'm not sure that I understand why this would be a problem. Does this mean that the engine can't achieve the "rated" RPM in cruise with the prop you have selected due to decreased torque? If the engine WILL turn the prop at the "rated" RPM in cruise, isn't this sufficient?
 
captainron said:
Mel, I'm not sure that I understand why this would be a problem. Does this mean that the engine can't achieve the "rated" RPM in cruise with the prop you have selected due to decreased torque? If the engine WILL turn the prop at the "rated" RPM in cruise, isn't this sufficient?
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After just completing the total rebuild of a '74 Bug, I'm now a full-fledged member of the VW community. :)

The problem with the VW aircraft engines is the rated power occurs in the 3300-3600 rpm range. This means if the prop tip speeds are to be restricted to subsonic range in order to achieve good efficiency and reduce noise on a direct-drive VW-based engine, a small diameter, steeply pitched prop must be fitted. This really restricts the performance envelope. Good cruise performance can be achieved but climb suffers.

If the engine is propped to keep prop rpm in a more efficient 2600-2900 rpm range, the engine can't develop anywhere near its rated power/torque. A VW engine with a redrive would allow a larger diameter prop but that increases the complexity of the installation.
 
Sam Buchanan said:
After just completing the total rebuild of a '74 Bug, I'm now a full-fledged member of the VW community. :)

The problem with the VW aircraft engines is the rated power occurs in the 3300-3600 rpm range. This means if the prop tip speeds are to be restricted to subsonic range in order to achieve good efficiency and reduce noise on a direct-drive VW-based engine, a small diameter, steeply pitched prop must be fitted. This really restricts the performance envelope. Good cruise performance can be achieved but climb suffers.

If the engine is propped to keep prop rpm in a more efficient 2600-2900 rpm range, the engine can't develop anywhere near its rated power/torque. A VW engine with a redrive would allow a larger diameter prop but that increases the complexity of the installation.
Click to expand...

Not these engines. Cam and crankshaft made for max torque below 3000 RPM.
http://www.sauer-flugmotorenbau.de/html/engines.html On the other hand, when a Rotax weighs less and costs the same, why bother...
 
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