Alessandro
Topic Author
Posts: 4962
Joined: Wed Sep 12, 2001 3:13 am

Wankel Engines

Sun Jun 09, 2002 2:16 am

Anyone have any thoughts about it? As far as I understand the only car engine that is good enough for flying ultra light planes with is the Mazda Wankel engines. Some companies build wankel engines for ultra lights but
they´re obviously more expensive, I wonder if the Mazda RX8 engine (released
next year) will find its ways into airplane as well?
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pmk
Posts: 609
Joined: Wed May 26, 1999 10:07 am

RE: Wankel Engines

Sun Jun 09, 2002 3:06 am

No. The RX-8 uses the same engine that has been around since the 1970's. The automotive wankel does not package well and does not have a big enough thrust bearing for A/C ops.
 
Accidentally
Posts: 612
Joined: Sun Dec 10, 2000 7:33 am

RE: Wankel Engines

Sun Jun 09, 2002 6:09 am

Site devoted to rotary wankel aviation:
http://www.rotaryaviation.com/

Soon to be Wankel powered RV-8:
http://www.rotaryaviation.com/RV8Project.htm

Some more wankel aircraft stuff:
http://www.monito.com/wankel/aircraft.html

Even more:
http://members.rogers.com/flyrotary/

You may find your answer in one of those links  Smile/happy/getting dizzy
Indianapolis, IN
 
PPGMD
Posts: 2398
Joined: Sun Sep 30, 2001 5:39 am

RE: Wankel Engines

Sun Jun 09, 2002 10:54 am

If I remeber correctly he (AA_Cam) believes that staying away from Expiermentals is "Risk Management."

Ultra-lights are fun, I'm right now trying to get a ride in the Turbine (old APU) powered Dragon Fly that they have at Quest Air.
At worst, you screw up and die.
 
pmk
Posts: 609
Joined: Wed May 26, 1999 10:07 am

RE: Wankel Engines

Sun Jun 09, 2002 7:51 pm

Folks:

I don't care what the experimental croud says the Toyo-Kogyo (Mazda) rotary is not a safe aircraft engine. Even after replacement of the thrust bearing the wafers do not have adequate strength to pull the load of an aircraft! Experimental aircraft are fine, but don't use an automotive engine! Never send a boy to do a man's job!

Peter
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Wankel Engines

Sun Jun 09, 2002 11:01 pm

Oh, plenty of UL aircraft out there flying with automotive engines. And by all means, do so. But remember that you'll probably only have one ignition system for starters and fly them like you would fly a glider. That is, always have a usable landing spot within reach should the engine quit.

A single engine is an unreliable thing, even if it is a thrustworthy Lycoming that is creating the noise and vibrations. Pilots with a glider background do a better job of staying out of the powered accident statistics for a reason...

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
FordLover
Posts: 189
Joined: Wed Sep 26, 2001 3:12 am

RE: Wankel Engines

Mon Jun 10, 2002 1:13 pm

Didn't somebody try this a few years back in the unlimited race in Reno? Trying to provide an alternative to hacking up warbirds. I recall it being twin rotary engined, called the Pond Racer, and Burt Rutan having a hand in it. Anybody else remember this, or is my imagination running away with me? As far as auto conversions go, I've got no problem with them. I'm considering building a homebuilt now called the Blanton V-6 STOL. It uses a Piper Pacer as a source of parts, and is powered by a converted Ford 3.8L V-6 (perfect for me  Smile )
 
geotrash
Posts: 293
Joined: Sun Jun 17, 2001 1:25 am

RE: Wankel Engines

Mon Jun 10, 2002 3:06 pm

I have rebuilt Mazda Rotarys in the past...mostly just replaced the apex seals. There is no way that the thrust bearing in that engine is designed to take the loads of propelling an aircraft- ultralight or otherwise. The same goes for most any automotive engine. Auto engines are designed for minimal longitudinal force, since the transfer of energy in an automotive transmission is via gears and so is a lateral force. The rear main bearing is the largest of all of the bearings in most auto engines to compensate for this. Other reasons I can think of to not use an automotive engine are:

-Liquid cooling- a very failure-prone system
-Ignition has no magnetos and so is dependent upon the chassis electrical system to provide power for spark
-No ignition redundancy
-Less oil capacity
-Internal parts are not fastened with castellated nuts and could loosen
-carbs or fuel injection systems are burdened with complexity to meet automobile smog regulations
-often use timing belts to drive the camshaft, or sometimes contain plastic cam sprockets or timing gears
-Have not passed the rigorous FAA testing standards
-Many more minuses can be listed

I wouldn't fly in ANY aircraft that uses an automobile engine for propulsion, nor should you.

-Geo
 
T prop
Posts: 909
Joined: Tue Apr 03, 2001 4:33 pm

RE: Wankel Engines

Mon Jun 10, 2002 4:27 pm

What's the deal with the thrust bearing? Automotive engines make their power to high in the rpm band to drive a prop directly, they must drive some kind of reduction gearbox. Is it not the reduction gearbox that takes the thrust load? If so the thrust bearing in the engine should not be a problem.

T prop.
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Wankel Engines

Mon Jun 10, 2002 6:50 pm

T prop,
egg-zactly. The words "knee-jerk reaction" come to mind, don't they? Big grin

"...and neither should you". That's a rather arrogant and patronizing thing to say.

I repeat what I said - fly using a rubber cord engine if you want. Just be aware that it not only might but WILL quit on you one day if you fly enough. This goes for all single engine aircraft - don't ever put yourself in a situation where you can't accept the consequences of your engine suddenly emitting that infamous deafening silence. Heck, most light twins are barely single engine capable and really demand a pilot who knows what he or she is doing if an engine goes out. It can be argued that light twins are less safe than single engine aircraft. You're twice as likely to have an engine quit, and if you won't make it on one engine... the odds are stacked against you.

That being said, an automotive engine is far more likely to quit on you. You should consider this when determining the risk you're prepared to take. The old probability of an event vs. the consequences of the event judgement call.

OTOH, I've read some accident reports where people have flown with so poorly maintained engines that the reliability was far less than that of my old VW Golf. Most G/A engines are 60's designs at best and need to be properly maintained if you are to have the extra reliability. I'd say that a poorly maintained modern auto engine will most likely beat a poorly maintained G/A engine...

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
L-188
Posts: 29874
Joined: Wed Jul 07, 1999 11:27 am

RE: Wankel Engines

Mon Jun 10, 2002 6:55 pm

If it makes you feel better, Rotax engines started out in snowmobiles.

Shoot even Continental and Franklin engines drive ground power units.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
PPGMD
Posts: 2398
Joined: Sun Sep 30, 2001 5:39 am

RE: Wankel Engines

Mon Jun 10, 2002 10:15 pm

Just as long as you are prepared to fly a glider at any time, doies it really make a diffrence.
At worst, you screw up and die.
 
TurbineBeaver
Posts: 1511
Joined: Fri Jan 11, 2002 1:50 am

RE: Wankel Engines

Tue Jun 11, 2002 3:51 pm

Wanker Engines!?!?

...I wonder what their slogan is.
 
Squigee
Posts: 634
Joined: Sun May 20, 2001 3:21 pm

RE: Wankel Engines

Wed Jun 12, 2002 2:42 am

I believe it's "Wanker Engines, not to be confused with Wankel engines."
Someday, we'll look back at this, laugh nervously, and then change the subject.
 
TurbineBeaver
Posts: 1511
Joined: Fri Jan 11, 2002 1:50 am

RE: Wankel Engines

Wed Jun 12, 2002 6:43 am

Oh. I thought the slogan for Wanker Engines would be:

"Suck, squeeze, bang, blow!"

TB
 
pmk
Posts: 609
Joined: Wed May 26, 1999 10:07 am

RE: Wankel Engines

Thu Jun 13, 2002 9:59 pm

Anybody who has owned a Wankel (named for the inventor) knows that they are not reliable on the ground! The plugs are prone to fouling, the ignition is cantankerous, and frankly we do come back to the whole thrust bearing thing. Regardless of the use of a small transmission the engine has more thrust placed on the rotor shaft (think like a crankshaft) which does a lot of things, all of them bad, including increasing the wear on the all important apex seals. Now if anybody wants the exact reasons and wear points I'll give them to you. BTW a GA engine with magnetos is going to spark when it comes around, not so with an automotive engine.

Peter
 
T prop
Posts: 909
Joined: Tue Apr 03, 2001 4:33 pm

RE: Wankel Engines

Fri Jun 14, 2002 7:53 pm

Peter,

Some posts above imply that propeller thrust loads are transmitted to the engine crankshaft. In a direct drive application this would be true and it would require an appropriate thrust bearing. However when a small auto engine is used in an aircraft the RGB is taking the propeller thrust load and does NOT transmit it to the engine crankshaft. So therefore the only thrust loads that need to be controlled are what the crankshaft generates as it floats back and forth, these loads are light and a heavy duty thrust bearing is not required.

I find it hard to believe that the design of the wankel somehow causes it to generate higher thrust loads by it self internally when it is run harder. Since I am not familiar with the inner workings of the wankel, could you please explain how this happens.


T prop.

 
Alessandro
Topic Author
Posts: 4962
Joined: Wed Sep 12, 2001 3:13 am

RE: Wankel Engines

Thu Jun 20, 2002 4:17 am

Well, when the RX8 comes, I wonder how long it will take until someone will
try it out in an exprimental plane? The RX7 sure have its supporters among exprimental planes, more
wankel engines made makes lower price, then after market dealers start to
develope kits to improve the performance and any deaths related to their
products is very bad advertising. Anyone knows if any exprimental planes
with Mazda wankel engines actually have had an lethal crash?
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