classicauto

iTrader: (3)

My Dad is into airplanes and one of his buddies who is building a J-3 cub asked me about rotaries for a plane the other day.

I was just curious if Joe "fantastic" ferguson or anyone else had any info on what this guy could/should do to prep the motor for things like roll-over's, high altitude etc.

I think I saw someonepost something about a 4 rotor airplane engine a while back, I'd be interested in some info on that setup also since this guy is a real speed freak....

Anything I can get.........

Feds

Rotary Aviation...

rotaryaviation.com

From what I've read, airplane motors need all kinds of extra juju to make sure they don't blow up and cause you to fall out of the sky...

classicauto

iTrader: (3)

mmmmm yeah falling out of the sky is no fun.....unless thats what you were trying to do, or paid your skydive instructor for

thanks for the link, I had a total brain fart there....hehe

dufourmike

iTrader: (1)

6mm apex seals are a good place to start. p-ports or turbos as well, as there is less air for the squish.

Feds

6mm!?!?!? Are you knucking Futs!

I'll second the air part.

trydis7

iTrader: (1)

Also Try:
http://lancaironline.net/lists/flyrotary/List.html
http://www.rotaryeng.net/

Amur_

Google for Tracy Crook and you'll find plenty of info and leads. He's the biggest name in that field...

no_name

A 12a is an acceptable weight for a J-3. I thought about desiging a cliped wing aerobatic J-3 with a fuel injected mild street port 12a with 150hp.

A 12a will work well with aircraft. Very little mods are needed. You will most likly have to go dry sump oil system ( not hard), and convert to FI ( still trying to figure it out, but it does nto seem as hard or expensive as it is made out to seem). Most of the stuff out their is 13b, and thus needs to have its firing system changed. You could spend howeve rmany thousands of dollars this costs, or jsut have a funky looking cowling and run teh current ignition set up on teh 12a. ( If you read up real solutions inc, said they wanted to originaly uses a simaler ignition system to a 12a but found it to bulky to fit under most aircraft cowlings. you could easily make a cowling that looks decen for a 12a.

Weight wize it is a bit heavier then a Lycoming O-235 (installed weights). However, since it is smaller it will sit back further so the CG should not be disruped.

The most expesnive thing would be the gear reduction unit ( I would say real soloutions makes the best one) which will run about 5 grand CAD, new shiped to your door.

A reliable 12a for aviation with 130-150hp can be built for around $3000 if you do all the work you self. Add the gear reduction unit and your looking at close to 8 grand CAD.

This seems steep but a lycoming O-235 with 130hp costs about 15 Grand US used. you could probably find one for about 10 grand with alot of hours on it.

The main saving is the rebuild cost. You have a fresh motor for 8 grand, vs an old used one for 12 grand. Rebuilding will not cost alot if you do the work yourself ( or send it out), rebuilding an O-235 is about 15 grand US because you will mos tlikly have to send it out.


I forgot to mention when I was tlaking about weights, and the rotoary being slighltly heavier.... I was talking about the installed weights including reduction units.

Hope that helps ( and was legible, and understandable lol)

doridori-rx7

iTrader: (3)

a rotary , compared to a similar sized/powered conti or lycomb. can be built firewall foreward in a std 13B NA P port for 1/2 what the above are worth.. and that's on restricted throttle to reduce power and including dual/redundant ECU setup. weight wise they have worked perfectly in everything from a cub sized 2 seater to a 172 comparable 4 seater. whith a much better performance envelope then any aircraft specific pistion motor , with less harmonics and way way way less wear at constant high speed load.

unlike a conti or lycomb. the rotary is not limited by 1940-50's design technology via certifications and legal nightmares. Downside is it's not a certified aircraft motor..

there is also a Wankel motors distributor in ontario somewhere as well you can look up Mistral aircraft of Switzerland for thier version of a Mazda rotary design updated for aircraft use. eg: recast housings with better cooling system...

Alak

iTrader: (9)

Aviator 902S I think would be guy to PM.


A) Hes a Rotor Head.

B) Hes an Aircraft Mechanic.

doridori-rx7

iTrader: (3)

AE's aren't exactly the first people to talk to about non certified engines or exp/kit planes..

Alak

iTrader: (9)

I suppose not everyone in the Aircraft buisiness knows all the ropes.


However, Brett is pretty knowlegdable about specifically this topic. Considering hes been researching it for like, as long as Ive known him. Now that he has the shop space, hes going to start building something with wings anyday now.


I can hear the phone calls for a shophand already.....

Feds

Bah, just go LS1.

no_name

Thier was something Iw anted to say but I forgot. IT was very useful too lol....

If I rember it I will post it.

Aviator 902S

Agreed. Most AME types are very biased against any auto conversion and homebuilt aircraft in general. Even those few who are also pilots cast a very jaundiced eye on anything that doesn't require the services of an AME to (legally) maintain. (Conflict of interest, perhaps?)

Having said that, I have been researching homebuilt aircraft since before I learned to fly. And I learned to fly several years before I got into aircraft maintenance. I have heard from countless AMEs what a terrible choice auto engines (and especially "them biodegradable Wankel motors") are for any aircraft and how all homebuilt planes are deathtraps and how they are no match for certified aircraft. But I have yet to hear this particular set of opinions from anybody (AMEs or otherwise) who knows what the **** they are talking about.

Asking most AMEs for advice on homebuilts and auto-conversions is like going to a dentist for a pap smear--- they are highly trained, but their skill set does not encompass that required to build a decent sport plane and power it with an engine different from the standard air-cooled Lycoming or Continental. Not that they can't learn how (after all, they are aircraft technicians), but they have not done the research.

Tracy Crook (whose work I have followed since long before most had ever heard of him) answers just about any question you may have on rotary engined aircraft. His Renesis-powered RV4 sport plane has a firewall-forward weight of just over 300 lbs--- about 60 lbs less than that of the Lycoming O-320 installation that it replaces and upwards of 40 more horses. All this with a time-before-overhaul (TBO) equal to or greater than that of the certified Lycoming engine (!) He is currently building a 20B-powered RV8--- which is like an RV4 on steroids.

One caveat to the rotary engine used in aircraft is harmonics and the effects they can have on propellers. The rotary has way less vibration than aircraft piston engines do, but the frequency of the vibration that is present is much higher. This resonance, when resonating at the same frequency as the prop at certain rpms, can cause the prop to fail catastrophically. This is a problem with metal props, but going with either a wood or composite prop will cure this trait.

btw, someone in an earlier post aluded to the notion that if your airplane engine quits you'll "fall out of the sky." Uh, no. If your wings or elevators fall off you'll fall out of the sky. If your engine quits you simply point the nose down a few degrees and glide back down--- hopefully to a smooth runway, highway or open field. The glide ratio may not be as favourable as that of a glider but you will be able to glide.

The only way an engine failure will cause you to "drop out of the sky" is if the engine falls off the nose of the aircraft, thereby causing the mother of all too-far-aft-center-of-gravity situations--- a scenario that could happen if the prop throws a blade. If the pilot can't shut the engine off quickly enough in this instance the vibrations could be sufficient to rip the engine completely off
its mounts.

Aviator 902S

Uh, a J-3 cub is a certified aircraft and therefore requires a certified aircraft engine by law. The homebuilt category of aircraft may use non-certified engines, but unless your dad's buddy can convince Transport Canada that he has built at least 51% of that aircraft it will not qualify as a homebuilt and will therefore not be eligible for an auto conversion. The rotary's firewall-forward weight would probably be a tad heavy for a J-3 anyway.

However, if he's building a replica J-3 from a kit or plans there's no problem with an auto conversion from a legal standpoint.

BTW, as long as any of the aerobatic maneuvers planned don't go negative (ie: the pilot hangs from his harness) the plane won't need an inverted oiling system or a flop tube in the fuel tank. This means that most of the more fun maneuvers (rolls, inside loops, cuban 8's, spins, etc.) are perfectly doable. Sustained inverted flight, outside loops and hesitation rolls however are out of the question.

Feds

See, I told you that you could fall out of the sky

You'll never catch me in a homebuilt, or more than line-of-sight from shore, but at the same time, 2 of my cars and my motorcycle are basically built ground-up by me in my garage.

Different risk tolerance.

classicauto

iTrader: (3)

Yes just for clarification.......its was a J3-cub. They have some other kind of wings on it...tailorcraft I think??....because apparently the cub wings don't support sustained inverted flight. As well as some pretty extensive modifications to the airframe itself. But it will be classed as a homebuilt, although from conversations I over heard it will be but, "just by a nose".

Which is why I was curious about the prep for upside down action!! haha

R.P.M.

iTrader: (3)

Joe....I'll build him a motor just like yours.....then we'll dry sump it, put a T-72 turbo on it, then he can do all the barrel rolls he wants at high altitude! LOL. I'd love to see an airplane taxi-ing out to the runway goin BRAP BRAP BRAP hahaha.

Theres a guy in Port Elgin, near the shop here, who builds aircraft and was asking me about building engines for his planes. The guy really did his research into all the different rotary parts that are available, like Atkins seals, JHB Cermet coating, lapping and re-nitriding ect ect, and was really surprsied when I showed him the JHB Cermet housings I had.
He's not quite ready to have a motor built for his plane yet, but he said he'd be bringing lots of business my way when he does. Apparently he has alot of requests for rotary powered planes and just never knew there was an engine builder so close to him LOL.

Aaron Cake

iTrader: (1)

What sort of liability is attached to building an engine for an aircraft? Something I've always wondered...

Alak

iTrader: (9)

How would you warrenty a motor like that? Its not like it has an odometer.


You could use an altimeter. 2 Years or 20,000 feet.

classicauto

iTrader: (3)

Hobbes meter (hours)

coldfire

iTrader: (1)

Would a turbo actually be a good idea for these things?
the whole constant load issue. I mean, just imagine a turbo at full boost for 4 hours straight or something...

Aaron Cake

iTrader: (1)

Turbos are often used to make sure the engine produces enough power at high altitudes where the air is thin, and to give extra power during takeoff.

classicauto

iTrader: (3)

Well thanks for the info guys!!

Joe - Ill make some suggestions to him about having a Joe "fantastic" ferguson rotary power his bird.

rotary power on the streets, rotary power in the skies.....anyone have a rotary powered sea-doo??? lol