I picked up my single rotor 12A project over the weekend and I am interested
to know how many guys out there are working on or have single rotor engines.
I know most of you are interested in 2 or 3 rotor engines and I do not want
to bog down the list, but I do have some questions if there is anyone out
there with a single rotor engine.

I noticed that Richard made reference to his single rotor yesterday in an
email to the list.

Jeff LeTempt
Dragonfly N41GK

Yes, Jeff, I had my single rotor running for two years now.
It is a p-port with compound AL side housings. I had been bogged down for a
while with building a house, but  I am slowly getting back to it again now.
The side housings so far are prof-of-principle configuration, meaning, not
flyable. This is going to change next with castings being used,
accommodating final design features.
For the 12A based version, the FF weight is 170lb.
I will certainly try to answer your questions if I can.

Richard Sohn
N-2071U

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.

Richard,

Thanks in advance for the help.  I know nothing about the history of the
engine that I bought.  The Ross 3.17:1 PSRU appears to be new and unused and
the engine externally looks very nice.  It does not have a starter or
alternator.  The water pump housing has been modified with HUGE anodized
fittings.  It has a thin wall steel tube intake manifold with a Weber carb.
No exhaust system.  No oil filter or cooler yet.  The main pulley is not
present on the exposed end of the concentric shaft nor is the water pump
pulley.  No ignition system, but it does look like there is a later model
distributor installed that just has a few wires sticking out (2 or 3 I
think).

This engine will go on a tricycle gear Dragonfly that was previously powered
by a VW 2180.  I would like to have a good solid 80 HP for take-off and
climb (would love to have 100 HP).  I am more into the economy cruise any
will probably typically cruise using about 60'ish HP.  I am not all that
interested in tweaking every last HP out of the engine, I am way more
interested in reliability, low maintenance, and longevity.  Based on the
performance of my MK-IIH Dragonfly powered with a L2000 Limbach I expect a
cruise speed of about 140 MHP IAS.

I am considering EFI/EI over the carb and ?? ignition.  The Tracy Crook EC2
looks very interesting right now.  I am very interested to hear your
recommendations on this.  The Crook EC2 might add a few hundred $ to the
total cost, but over the life of the airplane that cost is insignificant.

Do you have to do anything special with counterweights to balance the
engine?

Not sure what I will use for a radiator or where I will mount it yet.
Several Dragonfly builders using water cooled engines (Subaru's) have been
very happy with a P-51 style scoop on the belly of the fuselage.  With the
small size of the engine and the long PSRU, I think it would be possible to
mount the radiator(s) in the engine cowl.  That would almost certainly
reduce the weight and complexity of the water cooling system.

There is a partial engine mount that looks like it should work quite well
and the oil pan looks very good.

I will probably come up with a few hundred more questions - sorry.  If I get
to be too much of a pest just let me know.

Thank you very much for your advice!!

Jeff
Jeffrey.letempt@us.army.mil
Dragonfly MK-IIH N41GK
Rolla, MO

Ask away Jeff.

Paul Lamar


The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.