Hi Paul i'd like to subscribe to the rotary newsletter as i am building the
 airframe of my tango XR.

 I was planning to go with the subaru EJ22 that i bought along with the kit
 but i am busy gathering information on automotive applications for aircraft
 to try and understand better why the reliability rate is less than aircraft
 engines and to try and avoid the pitfalls and mistakes that have
 contributed towards a lower reliability rate than equivalent aircraft
 engines.

 I am interested in the rotary because they appear to be robust, however
 what is not clear and what i would really like to know is why with the
 amount of expertise out there on rotary engine conversions, and the number
 of years they have been in use in aircraft applications, why there are not
 more successful rotary aircraft conversions seen on the flight line.
 Hopefully a bit of research and reading will make this clear.

 Thank you by the way for the excellent book "cooling your wankel", i have
 no technical or engineering background but i found it logical and easy to
 follow and i was planning to apply some of the principles of cooling to my
 planned subaru setup.

 regards

 Alex Molteno

 Welcome Alex.

 Read the web site below and ask any question no matter how dumb it seems
 to you.

 The main problem with auto engines is the duty cycle. An auto engine is
 only expected
 to put out 40 or 50 HP indefinitely. An aircraft engine is 150 HP or higher
 continuously. The main difffereces in the engines are the materials the
 moving parts
 are made of. Things like powered metal rods and cast iron crankshafts  are
 typical
 for automotive engines. Of course these can be changed in some engines
 used for auto
 racing but that gets expensive as a real aircraft engine. The rotary is an
 exception
 as the stresses on the moving parts are much much lower. Nothing is
 stopping and
 starting up again as happens in reciprocating  piston engines.

 The other thing is carbs and magnetos are intrinsically more reliable than
 home installed EFI.

 It takes more work to install a rotary. Many people just want to
 circumvent the FAA
 3rd party maintenance rules for certified airplanes so they build an
 experimental kit
 and install a certified  aircraft engine. They just want to fly and the
 cost of an
 aircraft engine is higher than a rotary but not more than about double.

 The big rotary advantages comes with the ability of the rotary to run on
 low cost,
 low octane,  and less expensive  auto gas. Also in the remote chance you
 wear it out
 it is much faster and cheaper to overhaul it.

 It is also very smooth so in the air it is far less fatiguing.

 If you do go with the Soob you need to disassemble it and use helicoils in
 the head
 bolt threads located in the aluminum block. These threads fatigue under the
 continuous pounding and head gasket failure results. The corresponding
 rotary engine
 tension bolts are threaded into the cast iron front end housing. Fatigue
 on these
 threads are unheard of. Of course the Soob exhaust valves are not the same
 quality as
 aircraft exhaust valves and that is also a weak link. The rotary of course
 has no
 exhaust valves. Typically exhaust valves are the weakest link in certified
 aircraft
 engines as well.

 Paul Lamar

thanks Paul, i will investigate all a bit further, the rotary is very
intriguing so far,

best regards,

Alex

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