Planetary gear drive for corvair, Duel plug heads

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Midniteoyl

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now that I read and think about the whole idea of duel plugs and ignition items, it seems that we as consumer's have only been lead down a path to believe one system is needed over the other. in my case it was Mr. Wynne and his writings on corvair conversions. but unfortunatley as of to date as a manual owner of Mr. Wynne I have not been contacted and no effort has been made to answer my questions
Maybe if you quit taking sniping shots at him, he would be more willing to answer your questions.

Just a thought..


And, a warning.
 

Bill Clapp

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The reality is that after thousands of hours behind corvair engines Ive not had a failure of the distributor or plugs. I know that there are areas where we can improve the reliability of the design for aircraft use. The biggest failure in any of these components has more to do with the pilot than any one component (for the most part) I've talked to two people this week through their first flights on brand new aircraft and It is probably the most important talk I give...and very little to do with any individual component. Many things are doable - but the return on the time and investment has to make sense as well.

For that reason, I dont focus as much at this time on dual ignition more complex drive units.
Back to building airplanes.... :)
 

akwrencher

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I spoke to an auto-engine converter years ago about the lack of dual plugs. He said modern electronic ignitions generate a much "hotter" spark and they don't tend to foul. Spark strength not affected by low RPMs, like a magneto is.

I don't think I've had plug problems in a car since ~1982.

Ron Wanttaja
100%. I have had a number of cases in the shop with bad or fouled plugs, but I can't think of any off the top of my head that weren't caused by some other issue, i.e., they were the symptom of another more serious problem.
 

WonderousMountain

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Have you looked into the planetaries used by rotary engine guys? They've been using them a good while and use off the shelf auto components.

LuPi
 

don january

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Ok duel ignition duel sparkplugs. and a third pickup off your crank, and by the way all sources come off your crank! what else in the motor runs with crank? water, air,time?
 

don january

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if you can trap the energy coming off the rod's and pistons, like the crank maybe thats the next step, or hidden step??
 

RonL

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With proper engineering and great care, the sliding motion of the pistons inside the cylinders can produce electrical energy. Of course it's not free, but the mass of copper and magnets would be a small fraction of the weight of an external configuration.
 

TerryM76

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akwrencher: one morning I pulled my father out of a downed pawnee to find out later that not one but 2 plugs on his engine failed. I dont know your air time but I've seen it first hand. If as a group we can work out and reach a safe long lasting cure for engine failure due to ignition, then as a forum we accomplished somethink great. Don
Be sure and correct me if I am wrong but I am rather certain that old Pawnee has dual ignition and that poor aircraft still suffered an unscheduled arrival. So,maybe dual ignition was not a great contributor for a successful flight in this instance. Was it the fuel perhaps or maybe tired components not operating or adjusted to specs?

Yes, I like the redundancy that dual ignition should provide but most aviation maintenance texts like to point out that dual ignition provides for better efficiency of the fuel-air mixture. As others have mentioned, single plugs with electronic ignition is extremely reliable. Both my Tundra and Accord had well over 150,000 miles and a decade of service before I replaced the plugs.

Now, from what I can see, we need someone to develop a reliable electronic fuel injection system that is of moderate cost. That is way out of my realm of expertise since I am more accustomed to working on carbs or mechanical fuel injection systems. I absolutely believe that simplicity goes hand in hand with reliability. WW and Bill Clapp and others I should name have contributed greatly to developing and promoting Corvair engines for aircraft applications. Maybe others with the savvy and resources can contribute by developing these systems further.

Terry
 

TFF

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I changed an engine in a Cirrus SR22 once, that had a Mag fail. The idiot pilot, who borrowed the plane, did not turn the bad mag off because he was scared it was going to stop. 10,000ft was plenty of altitude to check, but anyway. He flew it 150 miles with the bad mag occasionally firing random times, as the gear had lost some teeth. The misfiring mag burned holes in 3 pistons on a 400 hr engine, but it still flew. It takes a bunch to take a plane out as long as it is not on takeoff. We had a set of rings go in one cylinder, it pumped almost all the oil out in 10 minutes. Engine did not get damaged because pilot watched the gauges and he had an airport close. 15 minutes would have trashed the engine.
 

don january

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when your 8 ft, off the ground and at gross weight,unable to pull chemical dump because dump handle is wired shut to stop leak, a sick engine is a disaster if you can't get clearence over the trees. I feel the sick motor was just a small part to that crash. never block off one of your emergency units built into the aircraft. "No brainer"
 

ekimneirbo

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My idea is to drive a magneto off the rear of the engine.....
It can be done. Just some $ to design
If a mag was used as a backup ignition in case of electrical failures, does the prop on your Corvair have the ability
to turn the engine over after it has stopped running? I'm thinking that the backup mag could be coupled in the case of an engine out rather than continually driven.
 

Will Aldridge

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Some of the Rotary guys are using the magneto type ignition (stator?) system off an outboard engine, or at least it's been posted on the email list. But it's easy in the rotary since you can mount it between the psru and the block. Looks like a pretty sweet setup to me. Maybe something similar could be mounted on the back of the corvair?
 

don january

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I know William Wynne does the duel point set up in his conversion's, and as far as I know thats it. sure it's great inless the disributor fails. I've personanly have'nt read or heard of any problems. Not sure what Mr. Clapp is doing for his ignition? purly stock or also duel point? If you think about it there is just a small shaft keeping the engine fireing on corvairs and most all other motor's. Clapp states he has a good setup for the corvair in post 11 and that would be a good thing to invest in.
 

ekimneirbo

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I know William Wynne does the duel point set up in his conversion's, and as far as I know thats it. sure it's great inless the disributor fails. I've personanly have'nt read or heard of any problems. Not sure what Mr. Clapp is doing for his ignition? purly stock or also duel point? If you think about it there is just a small shaft keeping the engine fireing on corvairs and most all other motor's. Clapp states he has a good setup for the corvair in post 11 and that would be a good thing to invest in.
I don't think it would be that difficult to make some type of magneto backup that could be easily engaged in the event of a failed igniton. The thing about a continuously running mag is that it would wear unnecessarily while providing
no real benefit and it probably would sap a couple of hp. Having it available only when needed would help to assure extreme longevity.The question I have is that if the electrical system was the cause of failure and the starter wouldn't work......would the windmilling propellor be sufficient to restart if a mag was available?
 

don january

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IMO : If the prop size was big enough and airspeed fast enough then the Corvair would windmill. Many corvair engines have been flown without starter set up's front or rear. I find it odd that the leading authority's of the corvair convertion's do not chim in and give there expert opinion. I guess to busy !
 

Bill Clapp

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Just to answer a couple past questions. As far as the distributor, we have a purpose built one from an old core. It has 18-20 degrees of centrifugal advance built into it and a set of points and a Crane electronic pickup for a dual ignition source. Our distributors also incorporate a ball bearing for the main shaft to increase reliability and timing accuracy.

As far as windmilling, it really depends on each engine/prop combination and speed. You have to have enough are on the prop to overcome the static engine friction. A heavy or light prop may not have much effect other than flywheel enertia effect. A lighter prop would be easier to stop but also easier to get moving....You may have to try your combination as see what speed the engine would begin windmilling at. Be ready to do so over an airport :)

Hope this helps :)
 

ekimneirbo

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Just to answer a couple past questions. As far as the distributor, we have a purpose built one from an old core. It has 18-20 degrees of centrifugal advance built into it and a set of points and a Crane electronic pickup for a dual ignition source. Our distributors also incorporate a ball bearing for the main shaft to increase reliability and timing accuracy.

As far as windmilling, it really depends on each engine/prop combination and speed. You have to have enough are on the prop to overcome the static engine friction. A heavy or light prop may not have much effect other than flywheel enertia effect. A lighter prop would be easier to stop but also easier to get moving....You may have to try your combination as see what speed the engine would begin windmilling at. Be ready to do so over an airport :)

Hope this helps :)
Thanks......I probably would try it with the engine mounted on a trailer behind my truck. Then I could see what effect different speeds had.:)
 

BJC

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IMO : If the prop size was big enough and airspeed fast enough then the Corvair would windmill. Many corvair engines have been flown without starter set up's front or rear. I find it odd that the leading authority's of the corvair convertion's do not chim in and give there expert opinion. I guess to busy !

If you know why it quit running and can correct it right away (suitch back to the tank with fuel :nervous:) then a windmilling propeller / engine is a plus. If you need to glide to a suitable crash spot, a stopped propeller will produce a better glide ratio.


BJC

PS. It will windmill at a lower speed than will be required to start windmilling after it has stopped.
 

rv7charlie

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My understanding is that it was a simple planetary gear setup....Not sure if any were built or tested - they can have their own issues... heavy, harmonics, lubrication...and more. Would be neat to see one though....We are looking into a chain or belt drive to an offset shaft for another project...(skunk wrks....)
Sorry to be a little late with this (just beginning to catch up on threads here on HBA).

Bill,

Can you provide some examples to support your contentions about planetaries? Specific engines that are overweight, harmonic-plagued, have lube issues, more, due specifically to the use of planetary reduction drives?

Charlie
 

Bill Clapp

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Hey Charlie. I never got to see one of those planetary drives on a corvair so honestly not sure about all the development problems or benefits since its not flying. I just know that our direct drive setup is as easy as it gets (no extra parts!) It would be interesting to see one but not in our planning stages when what we have works well for the power range of the engine. I just remember all the problems that plagued Eggenfellner when he did his SUbaru conversions....a long story.

Bill
 
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