Hello; Gonzalo,

 

If you have been following the posts on this list for the last week or two, some of these issues have been addressed under the subjects of  ‘Questions on buying a rotary’ and ‘Fuel economy’.

 

There is little doubt that installing an alternative engine will take more time and effort than bolting on a Lycoming.  But for me, I had to do it in an effort to find a better way, and after 140 hours of flight with my Velocity 20B, I’d say it has been a successful effort. My criteria were more power, lighter weight, and higher reliability.

 

Yes; I had some difficulties with the engine control electronics.  But you can benefit from having those issues already addressed.  Those electronics are potentially very reliable, and provides a simplicity of operation that you will make you happy.

 

I had some cooling issues initially, mostly with the oil cooling; but these were overcome relatively easily by a modification to the inlet scoop, and adding a small oil/water heat exchanger.

 

I have the 2.17 : 1 reduction drive, and the engine is relatively loafing at 5400 rpm cruise.  Yes, the engine is running twice as fast the Lyc, but handles it with equal, or better ease - and considerably smoother.  The 20B is giving me power equivalent to the 260 hp IO540 at an all-up weight of an estimated 40-50 lbs less – including the weight of the radiators and the coolant.  Better yet is it allowed me to fabricate a smaller, more aerodynamic, engine cowl which is particularly beneficial in a pusher where is allows less disrupted air flow into the prop.

 

I am getting 20 miles/gallon fuel economy at true air speed near 200 mph.  I have not heard yet of another Velocity matching or exceeding this performance with a Lyc.

 

So the potential for something better is there.  It takes some extra effort, and is not for everybody.  I tend to believe that my engineering background was a big help, but obviously others with other backgrounds have also done very successful installations.  It’s not for everyone, and you need to enjoy some problem solving.  But if you didn’t have that; I don’t think you would be building your own airplane.

 

All the best,

 

Al G   http://members.cox.net/alg3/airplane.htm

 

 

 

 

 

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Gonzalo A. Giménez Celis
Sent: Sunday, March 08, 2009 6:51 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] New in the group.

 

Hi Group, my name is Gonzalo, I’m from Chile, building a Cozy MK IV and new in this group.

 

As you can imagine. Although I have a couple of years left of building, I’m moving ahead looking for engine options. Of all the alternatives I’ve founded in the web, always I come back to the same two options: the XP-360 and the Rotary.

 

The XP-360 represent, I think, the “traditional approach”, while the Rotary is like the new era. I’ve been reading a lot, and I think I can resume all my reading in one statement: the users of traditional general aviation engines (Lyc type) says that if I go with the rotary, I’ll expend more time trying to make it working than actually flying, so, after a while, I’ll become so tired that I’ll move to the Lyc type anyway, because the Rotary is less reliable.

 

I’ve meet Bulent Aliev, a very nice guy who showed me his aircraft (very, very nice) and he had a Rotary, and after 20 hour he moved to a XP-360. He told me that there are too much electronics involved with the Wankel. He told me that If I want to fly, use the Lyc.

 

On the other side, Bulent told me that the factory of the XP-360 is broke, so, the warranty is no longer valid. (supposed to be 3 years)

 

One very important issue I think is the maintenance and replacement parts. Aviation engines are SO expensive, while I think that the Rotary might be cheaper.

 

Also, I would like to have some information about some issues that the Lyc. says are the weak points of the Wankel, like high operating RPM, difficulties for cooling, too much electronics, and others…

 

At the end, to be honest I like very much the Rotary idea, so I’m asking you for opinion and experience, since I think that almost all the people who say that the Rotary doesn’t work actually has no experience with it.

 

Thanks a lot for your time.

 

Gonzalo

Santiago - Chile