Wood Prop Removal

Post-War Aeronca Champ airplanes
gusc
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Wood Prop Removal

Post by gusc » Sat Feb 06, 2016 19:04

I'm trying to remove the wood prop from my taper shaft A65 Cont but it won't budge.

I'm using the procedure I got from this forum and it worked well a few years ago.

I'm at the point of trying to do the 2-2 1/2 turns to pop the prop off but the amount of force I'm applying makes me nervous. I'm using a 4' pipe but it is only making a dent in the pipe by the 5/8" bolt, nothing is moving. I have the snap ring blocked so I'm just leaving it overnight with the pressure to see if that helps.

Any words of wisdom will be appreciated.
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

Paul Agaliotis
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Re: Wood Prop Removal

Post by Paul Agaliotis » Sun Feb 07, 2016 12:12

Gus,
It sounds like you're on the right track. Sometime you can give it a good whack on the nut to jar it loose. Protect the nut so you don't damage. Make sure you install it with a good grease or anti-sieze so you can get it off again.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

gusc
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Location: Ash Flat, AR
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Re: Wood Prop Removal

Post by gusc » Sun Feb 07, 2016 21:20

Paul,

I was never able to get more than one turn on the nut up against the split ring. Even with a four foot pipe and tapping with a rubber hammer nothing budged. I've broken enough things to know when to stop!

I finally gave up and removed the prop nuts and prop to get the cowling off. Probably a good thing since the prop bolts and hub had a nice layer of white corrosion which I removed and treated everything with Corrosion-X.

I staked the exh valve but only managed to improve the compression by 10 psi up to 30 psi cold, next door cyl shows 50/70 cold so it is obviously not good. So, I guess it is time to remove the cyl to find out the problem. I tried my borescope but couldn't get a view of the valves.
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

Paul Agaliotis
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Re: Wood Prop Removal

Post by Paul Agaliotis » Mon Feb 08, 2016 09:34

Gus,
Sorry to hear about the cylinders. Better to get it done before you have other problems. I flew the Champ yesterday with it's new engine, Boy that other one was tired.
With the prop hub, I have a prop bar made from a Ford Model T drive line. Real good steel and doesn't flex much. I use a steel double jack to smack the nut. Protect it as best as you can with a metal plate. Loosen the nut until your conscience hurts and let it sit a bit, smack it with the hammer and put a little more tension on the nut. Do this a few times and I've always had them free-up.
If you are using the little McCauley prop, be real careful in the bolt holes. My prop guy is seeing more rejects for bolt hole corrosion.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

gusc
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Re: Wood Prop Removal

Post by gusc » Thu Feb 11, 2016 21:45

Paul,

Thanks. I was not able to loosen the nut more than 1/2 turn the first go. Smacked it a few times with a rubber hammer. Let it sit overnight during some pretty good temp swings thinking that would help. Didn't loosen at all.

Then I turned it about another half turn until it took so much pull on a three foot pipe I chickened out when the pipe distorted at the 5/8 bolt. I know in my old age when something bad is about to happen!

My Sensenich wood prop probably absorbed some moisture and caused the corrosion so maybe it is better that I took it off so the hub bolt holes can air. Interestingly, the small Al hub bolt bushings didn't corrode?

After I staked it I tied a plastic bag over the exhaust and it slowly filled with air. It gained 10 psi after staking but is still 20 psi lower than the other three. From my experience exhaust valves just get worse so off it comes to see just what is the problem.

I did the bag test on the adjoining cyl and it didn't leak at all.
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

MikeB
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Re: Wood Prop Removal

Post by MikeB » Fri Feb 12, 2016 11:47

Gus,
For whatever it's worth I've been able to see 'most' of the valve and seat by pulling both plugs and running a 'bend a light' in the bottom plug hole and viewing through the top with the valve full open. Seems like the guides wear out on most of the little Continentals and let the valves dance around to the point where they start leaking and then it's all down hill from there. We just had an A65 with probably less then 500 hours on new Superiors and one exhaust valve started leaking. After trying all the 'tricks' finally pulled the jug and got the valve, seat and guide redone. Seems like they a new cylinder should last longer than that although this particular rig spends a lot of time going up and down, up and down, up and down. I think it was around $500 for repair at Bolduc.

Mike Berg

gusc
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Re: Wood Prop Removal

Post by gusc » Fri Feb 12, 2016 20:25

Mike,

Thanks. My borescope just won't bend enough to look at the valves so maybe your system will work.

However, I think I'll go ahead and pull the cyl anyway since I suspect your diagnosis is correct, this cyl only has 154 hr SMOH but has been sitting eight years.

Has anyone ever knurled these guides? I used to do that to my Franklin guides and it worked great.
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

MikeB
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Re: Wood Prop Removal

Post by MikeB » Sat Feb 13, 2016 10:01

Gus,
I've never had the guides knurled on an aircraft engine but used to do it a lot on auto and small engine types. The nice thing about knurling is it helps to hold oil in the guide surface for lubrication purposes and lets you run with a little less clearance although I'd stick to engine specs on aircraft engines. I have new ECI nickels on my 0200 and if I remember correctly they are manufactured with knurled guides. I do think the 'aftermarket' knurling process is probably a short term fix though.

When you mention sitting time, we have an A65 that sat in a Champ for probably 20 years without turning the prop then the Champ was restored (recovered, etc.), the engine left 'as is' and it's still flying even though it's lucky if it flies 10 hours a year. Compression leakage runs in the mid 70's every annual so I guess you never know. I had an engine (A65) that was IA?/AP rebuilt to zero time specs (his words) where the guides were so worn that the valves moved all over the place and had standard rings in a .015 over cylinder even though the log entry said "checked all ring gaps". Of course it had gone through a couple of owners before I got it so I was pretty much stuck with fixing it......so it goes.

Mike

gusc
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Re: Wood Prop Removal

Post by gusc » Mon Feb 15, 2016 00:27

My champ is in my shop about 50' from my back door so it has been constantly turned over all these years.

I am curious to get the cyl off and find out the actual problem. It is too cold to work on it now.
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

dlrude
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Re: Wood Prop Removal

Post by dlrude » Tue Feb 23, 2016 22:33

Hi Gus,

I have had a similar issue like yours with the hub.

I usually remove the the prop then unscrew the hub nut to a point where it was tight and I could not turn it any more due to strength limits and fear of doing damage.

I do not use a 4' pipe but rather an 18" extension from my 3/8" socket set.

Then I take a torch and heat the hub usually not real hot maybe a few hundred degrees as the paint browns in spots.

Usually when the hub heats up it pop forward. You could use a heat gun or propane torch if you are concerned about overheating.

When I reinstall I slop up the taper shaft and hub with anti-seize and sometimes bee's wax.

There is an Aeronca service note or letter or helps & hints that describes how to install and remove a hub this is superior IMHO to the stuff published in the modern magazines. I have been following that procedure for 25 years with no issues.

Hope this helps.

Dave
Last edited by dlrude on Fri Mar 11, 2016 08:09, edited 1 time in total.

bob turner
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Re: Wood Prop Removal

Post by bob turner » Wed Feb 24, 2016 13:22

Cub Club has a good article on loosening prop hubs. You machine an aluminum thing to fit the nut, put real pressure on the nut (I use a 3' bar and a steel mallet) and then whack the nut with machined fitting and a steel mallet.

One time I had some problems - I suspended the engine from the prop hub before whacking, with a cushion for the case studs about a half inch below. Whack! Engine dropped right out.

If you have been rotating the prop for about ten years on a regular basis without actual oil pressure, your problems are most likely rust.

gusc
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Re: Wood Prop Removal

Post by gusc » Fri Mar 11, 2016 01:50

Thanks,

I'll try heat next time. Taking the prop off was a good thing because I found the corrosion on the prop bolts.

I had no problem getting it off about a year before I parked it using the Cub Club method.

I suspect that running the engine for a few hours will make it easier next time, but for now cyl access is solved.
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8

dlrude
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Re: Wood Prop Removal

Post by dlrude » Fri Mar 11, 2016 08:16

The Cub club method and those like it use a higher torque than one will achieve with the Aeronca method.

That makes me curious about the incidence of cracked hubs using the high torque method. I wonder if there is a higher incidence of cracked keyways using the high torque method.

Dave

bob turner
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Re: Wood Prop Removal

Post by bob turner » Fri Mar 11, 2016 19:47

So how does one get to read a copy of the Aeronca method?

dlrude
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Re: Wood Prop Removal

Post by dlrude » Fri Mar 11, 2016 20:51

Hi Bob,

I tried to attach it but it says .pdf is not permitted, send me and email and I will send you the file. It is the Aeronca helps and hints #14 from 1961.

I like most the use of an 18" bar and no bigger, it avoids over torque.

I realize that I do not follow it exactly, my bad.

I put a lot of antisieze on the taper and the hub i.d. and the threads at the installation step #3.

Also on removal step #4 I apply heat if needed but normally it is not needed because of the antisieze.

BTW I usually have to clean some antisieze off the cowl and windshield after installation.

Dave

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