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5th Bearing - What is the Purpose?

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ahinsdale(at)yahoo.com
Guest

Posted: Sat Mar 22, 2008 3:57 pm Post subject: 5th Bearing - What is the Purpose?

Hello Listers



I have been reading the traffic on the 5th bearing for

the Corvair.  I posted this question on CORVAIRCRAFT a

while back and did not get an answer.  Simply put..

why would I want a 5th bearing?  My impression is that

it applies mostly to extended crankshafts as used in

some KRs, not really to the 601XL installation.



Thanks



Andy Hinsdale

Never miss a thing.  Make Yahoo your home page. 

http://www.yahoo.com/r/hs

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Sat Mar 22, 2008 5:41 pm Post subject: Re: 5th Bearing - What is the Purpose?

The idea is to shorten the distance to the 1st bearing, to transfer more prop load to the case. This may be simplistic, but then there seems to be opinions on this topic, so thats how I'll leave it. There have been some crank failures in the last year of so. I'm not the one to ask about its effectiveness, as I am so not qualified to discuss it.

_________________
“Always do what you are afraid to do.”
R.W. Emerson (1803-1882)

"Real freedom is the sustained act of being an individual." WW - 2009

"Life is a good deal...it's worth it" Feb 1969
Dorothy McCune

Kevin Bonds

Joined: 09 Jan 2006
Posts: 171
Location: Nashville, Tn

Posted: Sat Mar 22, 2008 6:11 pm Post subject: 5th Bearing - What is the Purpose?

Andy



This subject is in a state of evolution. We've had to adjust our thinking, on things, as some failures have occurred. There are a lot of improvements being suggested and worked on right now to make the Corvaircraft engine more bulletproof. I think the engine needs this. I would like a to feel a little more certain, that I have done all I can, to make my powerplant safe--before I install it on my plane and go flying. I have been contemplating different engines in case the Corvair becomes too complicated and heavy. 



I'm excited about many of the prospects (brand new cranks; 5th bearing, etc.). I'm excited to see where this may lead. I'm hoping that once the 5th bearing design is decided on; and the new cranks are tested; we can safely get rid of the harmonic balancer. This will help offset the added weight of the 5th bearing. My thinking is that the balancer was designed by GM to address a resonance issue in the car. We' ve changed so much that GM's research can't mean much. The new cranks will even be of a different alloy--which will certainly have different resonant characteristics. 



Kevin Bonds



 -------------- Original message ----------------------

From: Andrew Hinsdale <ahinsdale(at)yahoo.com>

 	  Quote: 	
		   

 

 Hello Listers

 

 I have been reading the traffic on the 5th bearing for

 the Corvair.  I posted this question on CORVAIRCRAFT a

 while back and did not get an answer.  Simply put..

 why would I want a 5th bearing?  My impression is that

 it applies mostly to extended crankshafts as used in

 some KRs, not really to the 601XL installation.

 

 Thanks

 

 Andy Hinsdale

 

 

 Never miss a thing.  Make Yahoo your home page. 

 http://www.yahoo.com/r/hs

_________________
KevinBonds
Nashville, TN
Plans-building Zenith CH601XL w/Corvair Power
http://home.comcast.net/~kevinbonds

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Sat Mar 22, 2008 6:16 pm Post subject: Re: 5th Bearing - What is the Purpose?

The corvair engine really wasn't designed for spinning a propeller.  Having the 5th bearing will take some of the precession loads out of the crank and transfer them to the engine case.



If you fly the engine gently you will probably never have any problems with crank breakage.  I am having the www.roysgarage.com made for my plane just for more peace of mind.



Today I dropped the case and crank off to Roy and showed him a full size blue print of the 1958 machining drawings of the engine.  He did take some notes.

_________________
Ron Lendon
WW Corvair with Roy's Garage 5th bearing
CH 601 XLB
N601LT - Flying
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
https://sites.google.com/site/corvairenginedata/

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Sun Mar 23, 2008 5:28 pm Post subject: Re: 5th Bearing - What is the Purpose?

I agree. Great engine, it's just needs some help becoming a true aircraft engine. Not much hlep, but some help. I' ve got 3 of them now ready to be rebuilt and just looking at them, you can see the aircraft engine in them. But they do need a little help getting there.



 	  Ron Lendon wrote: 	
		  The corvair engine really wasn't designed for spinning a propeller.  Having the 5th bearing will take some of the precession loads out of the crank and transfer them to the engine case.



If you fly the engine gently you will probably never have any problems with crank breakage.  I am having the www.roysgarage.com made for my plane just for more peace of mind.



Today I dropped the case and crank off to Roy and showed him a full size blue print of the 1958 machining drawings of the engine.  He did take some notes.

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Sun Mar 23, 2008 5:32 pm Post subject: Re: 5th Bearing - What is the Purpose?

By the way, how far apart do you two live? Geoff Heap and I are about 3 miles from each other. I'll tell you what, having other builders, that you actually like no less (I invited him to my wedding, we get together at least twice a month if not more), is friggin' priceless.



 	  Ron Lendon wrote: 	
		  The corvair engine really wasn't designed for spinning a propeller.  Having the 5th bearing will take some of the precession loads out of the crank and transfer them to the engine case.



If you fly the engine gently you will probably never have any problems with crank breakage.  I am having the www.roysgarage.com made for my plane just for more peace of mind.



Today I dropped the case and crank off to Roy and showed him a full size blue print of the 1958 machining drawings of the engine.  He did take some notes.

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Sun Mar 23, 2008 6:14 pm Post subject: Re: 5th Bearing - What is the Purpose?

I agree with ashontz, but I'm building a 701 and the corvair is already a little bit heavy for it. I'm not so concerned about the W&B but more about payload and range. I'm betting performance wise... its kick a$$ though. If I were building a 601 I'd have a corvair, continental or maybe an older franklin (don't know anything about the new ones)

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Sun Mar 23, 2008 6:28 pm Post subject: Re: 5th Bearing - What is the Purpose?

Andy,



Roy and I are about 3 hours apart by car.  I made the trip out to see what he was doing because it looked important, it was.  



Yesterday we met where we were both crossing paths about half way to transfer the case and crank and oil pump.

bill_dom(at)yahoo.com
Guest

Posted: Tue Mar 25, 2008 4:25 am Post subject: 5th Bearing - What is the Purpose?

Andy,



The purpose of the 5th bearing is not to extend the crankshaft, it is to avoid breaking the crankshaft due to the gyroscopic force of the propeller.



William Dominguez

Zodiac 601XL Plans

Miami Florida

http://www.geocities.com/bill_dom



[quote]-------------- Original message ----------------------

From: Andrew Hinsdale 

[quote] --> Zenith-List message posted by: Andrew Hinsdale 

 

 Hello Listers

 

 I have been reading the traffic on the 5th bearing for

 the Corvair.  I posted this question on CORVAIRCRAFT a

 while back and did not get an answer.  Simply put..

 why would I want a 5th bearing?  My impression is that

 it applies mostly to extended crankshafts as used in

 some KRs, not really to the 601XL installation.

 [quote][b]

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Tue Mar 25, 2008 5:17 am Post subject: Re: 5th Bearing - What is the Purpose?

Exactly! I think it's a good idea.



[quote="bill_dom(at)yahoo.com"]Andy,



The purpose of the 5th bearing is not to extend the crankshaft, it is to avoid breaking the crankshaft due to the gyroscopic force of the propeller.



William Dominguez

Zodiac 601XL Plans

Miami Florida

http://www.geocities.com/bill_dom



[quote]-------------- Original message ----------------------

From: Andrew Hinsdale 

[quote] --> Zenith-List message posted by: Andrew Hinsdale 

 

 Hello Listers

 

 I have been reading the traffic on the 5th bearing for

 the Corvair.  I posted this question on CORVAIRCRAFT a

 while back and did not get an answer.  Simply put..

 why would I want a 5th bearing?  My impression is that

 it applies mostly to extended crankshafts as used in

 some KRs, not really to the 601XL installation.

  	  Quote: 	
		  [b]

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