flyrotary@lancaironline.net Mailing List Archive

Dustin,

Where did you find a decent O-540 for $15k? I have not looked in a while but you may find a decent O-360 in that price range, but an O-540 will probably be twice that???

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Sunday, November 07, 2010 11:13
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Current "state of the art" in rotaries - potential Bearhawk install

Hi Dustin,
Answering the broad "what should I do " question is always a tall order. But in general, if you want a reliable 300HP your only option is a 20B. The 'all aluminum' version would be great (if it's real) but I doubt you could hit your target of $15K with that. Forget about 90+% of the car racer mods and just go with mild street porting. The peak loads we place on the engine are way less than a drag race application so the extra dowels are not necessary. The 20B in my RV-8 was built from mostly 13B parts except for the 20B center housing, crank and tension bolts. No other significant mods other than mild street port. Ceramic coating of the rotors is fine if done right but it has nothing to do with avoiding detonation. Use the 89 - 91 13B 9.7 : 1 CR rotors if possible.

Tracy

On Sun, Nov 7, 2010 at 1:15 PM, Dustin Lobner <dmlobner@gmail.com> wrote:

Hi everyone!

This is my first message here. My name is Dustin, I live in the Rockford area in Illinois. I'm going to be starting a Bearhawk in the next couple of months and am strongly considering a rotary conversion for it...it'll be a few years before I'm at the "need an engine" point, but I want to know what I want to do before I get there, hence research now. The three sentence background on the Bearhawk: It's a 4-place utility/STOL aircraft that's pretty much my dream plane. Typical engine installs are O-360s and O-540, max HP set at 260HP due to the weight of a 300 HP Lycoming. I'd be comfortable running about 300HP on it, with a max complete engine weight of 400 pounds.

I'm a metallurgical engineer at an aerospace company here in town. This, along with family, keep me very busy. As such, I'm interested in as close to a "turnkey" option that I can get (without forking over $+60k for something like a Mistral). I have extensive experience working on cars and motorcycles (and several friends who have a lot more), none working on a rotary though. I also have welding experience and will be buying a TIG welder as part of this project.

With all that in mind, how I want this to work out is to buy the big pieces and bolt them together and work out things like intake, exhaust, etc. I'm an engineer, I do like figuring out how to do stuff and engineering solutions to problems...but I worry about never finishing, hence wanting people who know what they are doing to make the big parts.

On with the questions...

#1a) I'd like to have an engine builder build me a "core engine", minus EFI, intake, exhaust, etc. Any recommended builders out there?
#1b) I emailed the folks at www.rotaryengine.com. I laid out my requirements and asked "what do you think I should do?" They aren't an aviation engine builder, so it'll be interesting to see what they come back with. In particular, they have all-aluminum engines (they bill themselves as the "home of the 3 rotor all-aluminum engine"). Any thoughts on them as a company or on the all-aluminum concept?
#2) I was planning on using Tracy's ECI3/EMS3/RD-1C reduction drive. I see that Tracy is active here, which is awesome. (Tracy, you seem like a nice guy, so no offense intended on the next statement here): Are there any other viable options for a rotary reduction or ECI/EMS system out there?
#3) Are there any recommended modifications to the engine to make it more reliable? There are a ton of things recommended by www.rotarengine.com (who sells the stuff, so take it with a pound of salt). These things include ceramic coatings of rotors to prevent detonation, various porting mods, oil-flow enhancement, cooling flow enhancement, installation of more dowel pins, etc.

I had (somewhat arbitrarily) set the cost I was willing to spend at $15k, about the cost of a decent used Lycoming O-540. If the cost of this can stay below that, awesome. I'd rather spend a bit more and get something "done right" than skimp and then have an engine or redrive blow up on me.

Tracy, I sent you an email with most of the above laid out. Feel free to ignore it, reply here if you wish.

Thanks in advance for any replies!

Dustin