Subject: Combined flight hours
From: paul
Date: 2/12/2015, 11:32 PM
To: AAA-rotaryengine


Hey group,

Do we have a handle on the combined flight hours in the rotary fleet?

Chris Cosman


You mean since 1973 when the first one flew?


Paul Lamar


Or some point in time that makes sense, like when Everett Hatch or Tracy first flew...

Chris Cosman


Lew Ross flew a Mooney and Dave Garber flew his huff and Puff in the early 70's. Then there was Duncan in Oklahoma selling Mazda conversions.  Everett and Tracy where not the first to fly.

Paul Lamar

I had someone recently question my wisdom for choosing the rotary for my design and told me there weren't very many flying and those that are don't accumulate many hours due to the need to constantly fiddle with them.
This gentleman was a proponent of certificated engines. Not having any hard numbers I said nothing at the time.

I would like to give him an answer. So here are my questions:

1.  How many aircraft have flown with a rotary?
2.  Of those how many still have the rotary installed?  Meaning some people swap out the rotary for a certificated engine after becoming frustrated.
3.  About what percentage of installs get past their teething problems in say the first 100 hrs of flight time, not ground run time?
4.  How many rotaries are currently flying annual to annual without
major issues?   I know the experimental crowd likes to fiddle and some
will make major changes just cause they feel like it.
5.  What is the highest time install you know of?

These are just some questions I could think of off the top of my head.
If you have other data you think is more pertinent I'd like to hear it.

Will Aldridge


1.  How many aircraft have flown with a rotary?

My guess is well over a hundread.

2.  Of those how many still have the rotary installed?  Meaning some people swap out the rotary for a certificated engine after becoming frustrated.

No idea.


3.  About what percentage of installs get past their teething problems in say the first 100 hrs of flight time, not ground run time?

  More lately since I wrote the book How to Cool Your Wankel. The major cause of
  failure in the past was cooling difficulties.

4.  How many rotaries are currently flying annual to annual without
major issues?   I know the experimental crowd likes to fiddle and some
will make major changes just cause they feel like it.

 My guess is dozens.

5.  What is the highest time install you know of?

 2500 hours in a gyro copter used for training. Most PP's put about only 50 hours a year
 or less than 100 hours per year.

A lot of people don't start until retirement age. Projects are some times sold several times before they fly. My over all goal is to cut the time necessary to install a rotary.

We now have a universal  motor mount kit and people to make gear boxes and P-ports.

EFI systems can be bought from multiple sources.
IMHO MoTec is the best but expensive http://www.motec.com/

I hope to have an open source simple system soon that anybody can program.
One can also use a carb. The 500 CFM 2 barrel Holley is the best IMHO.

Paul Lamar


Hi Paul,
   IMHO more people should turn on to the advantages of the Ellison or Rotec throttle bodies, they are awesome bits of gear. Having no float bowls they can be mounted in virtually any position.
They are simple devices and trouble free, when I retro fitted an Ellison onto my Long EZ I was impressed to say the least, I got about 10 % power increase and 10 % less fuel burn. I did over 700 hours with it before I sold my plane. It appeared to be very resistant to carb ice too, I flew with it on carb ice days also when others were having ice problems but never had to use carb heat no matter what throttle setting or power I used. BTW I will be using one ( a Rotec ) on my new RX8 Long EZ ( when I finally get it done ).

 Chris Hoskins





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