A75 engine on a VariEz

[Ratdog]

I have a VariEZ project and the opportunity to buy an overhauled A75 engine .  What are your thoughts on the A75 engine for a Variez. 

[Kent Ashton]

6 hours ago, Ratdog said:

I have a VariEZ project and the opportunity to buy an overhauled A75 engine .  What are your thoughts on the A75 engine for a Variez. 

I know nothing but I see the A75 is rated at 75 hp and an O-200 is 100 hp--1/3 more hp.  Gary Hertzler has done a lot with his (O-200?) engine.  He'd be the one to copy if I was building a Vari  

 

[Marc Zeitlin]

2 hours ago, Kent Ashton said:

I know nothing but I see the A75 is rated at 75 hp and an O-200 is 100 hp--1/3 more hp.  Gary Hertzler has done a lot with his (O-200?) engine.  He'd be the one to copy if I was building a Vari  

Gary has a Lycoming O-235 on his VE. Probably the most efficient one out there, but it's not a Continental.

Since the VE was originally designed for a Volkswagen engine, it'll fly with an A-75, if its lightweight and if you don't mind degraded performance, particularly in climb. Since very few VEs are lightweight, I certainly wouldn't recommend it.

[Ratdog]

Thanks .  I talked to david orr he said there was i guy in colorado with one and he use to say it was single pilot on hot days .  So it sounds like it would work .  Im more interested in economy my particular airframe was supposedly 650 lbs when it had a c85 on it . 

[Kent Ashton]

13 hours ago, Ratdog said:

Im more interested in economy my particular airframe was supposedly 650 lbs when it had a c85 on it . 

Consider that the takeoff roll for canards is longer than for tractor-engine airplanes and low HP is going to make it longer.  Then about half the time you will be flying in a headwind so you want to fly somewhat faster but a low-HP engine will not allow that.  Also, with a higher HP engine, you can always reduce power in cruise to extend your range.  As I recall, had an O-320 in my Cozy III that usually used about 6.5 GPH but one time I really pulled it back with tailwind to get max range and I remember it was only about 4.5 GPH.  Finally, there are times when you want to climb to get above some clouds or terrain and higher HP will help.  If you're really interested in efficiency, work on drag reduction.  Hertzler did a great job on that.

[slk23]

On 10/4/2023 at 4:07 PM, Marc Zeitlin said:

Gary has a Lycoming O-235 on his VE. Probably the most efficient one out there, but it's not a Continental.

Since the VE was originally designed for a Volkswagen engine, it'll fly with an A-75, if its lightweight and if you don't mind degraded performance, particularly in climb. Since very few VEs are lightweight, I certainly wouldn't recommend it.

Wasn't the VW engine only used in the prototype VariEze which was smaller than the redesigned, plans-built version?  Anyway, the VariEze plans do not mention the VW engine AFAIK.  Section IIA covers the  Continental A65, A75, C85, C90, and O-200, and section IIB covers the Lycoming O-235.  In my mind the O-200 and O-235 are by far the best choices.