aileron pulleys

[alwaysoar]

My IA is beginning my annual, and found four aileron pulleys on my '46 that show signs of having been too tight at one time (probably off another plane--my cables are loose). I cannot find the same pulleys in any catalogues. They are marked A229, are 1.755 diameter, 1.25 groove diameter, have a 3/8 hole with a 3/16 bushing. There are plenty of pulleys with the same OD, but not the same hole size. These are probably the wrong pulleys. What should I use for replacements?

Ed @BTV VT
TF 527

[Robert Lees]

Make them, or at least make new bushings. I used phosphor-bronze for new bushings on my old pulleys.

Pulley bore opened out and new phosphor-bronze bushes turned and press-fitted in. The bush rotates around the bolt, not the pulley rotating around the bush.
Bush is slightly wider than pulley, so preventing the side of the pulley interfering with the bracket.

Photo at https://www.Taylorcraft.org.uk/pulle...rol-cables.jpg

Cheaper than new ones.

Rob

[alwaysoar]

Rob, If I set out to make new pulleys or bushings it will take forever. I'd buy the new ones if I knew what to get. Does anyone out there have some they can sell?

Ed @BTV VT
TF 527

[Robert Lees]

Ed, check your PM's.
Rob

[alwaysoar]

What's a PM? If it has to do with my posting, I had some trouble posting my last reply and it appeared three times. I then deleted two of them--hope I did it right. At any rate, do you know where I can buy some pulleys? I'll never be able to make them.

Ed TF 527

[Marv]

Pulleys

Check with Forrest. Marv

[Grant S. Bailey]

Ed,

The modern replacement pulley (ball bearing) that you are looking for is Ralmark P/N 8-2478. These are the 1 3/4" dia pulleys. If you want to replace any of the 3" dia pulleys, the Ralmark part number is P/N 8-2479.

Their web site is www.ralmark.com

[Robert Lees]

PM is Private Messages

Rob

[alwaysoar]

pulleys and rebuilt ailersons

Thanks again for your help. Taylorcraft had the pulleys for $14.95, so I ordered four. It's a different part number that I lost already.


I have another question about the ailerons I'm rebuilding. First, do they need an IA's sign off to recover, or can an A&P sign them off for recover, or do they need a sign off at all before recover? I have as many answers to that question as there are mechanics out there.

2/ should the leading edges be nailed along the spar? My old spars were cracked where the leading edges had been nailed along the top and bottom of the spar. It seems to me they should not be nailed.

3/ Are the metal tip bows "structural" members? Same deal, except Forrest says no and I trust him, but my IA says yes.

Ed @BTV VT
TF 527

[taylorcraftbc65]

Aileron guides

Hey guys, we found the problem with both my ailerons drooping,
and this info might do someone some good. On my BC65, there were a set of cable guides that were behind the seat, at the top of the fuselage. on mine they were missing. We made up a set, and now everything is perfect. Hope this helps somebody, see
you at LaGrange. Sabrina

[Guest]

Re: aileron pulleys

Make them, or at least make new bushings. I used phosphor-bronze for new bushings on my old pulleys.

Pulley bore opened out and new phosphor-bronze bushes turned and press-fitted in. The bush rotates around the bolt, not the pulley rotating around the bush.
Bush is slightly wider than pulley, so preventing the side of the pulley interfering with the bracket.

Photo at https://www.Taylorcraft.org.uk/pulle...rol-cables.jpg

Cheaper than new ones.

Rob

Rob, how or why are you certain of this (in blue)?

I recall removing pulleys from a nearly new a/c and pulley rotated around the bushing.

Makes me think that was the intended design but I know it is not sufficient to prove it.

Have you seen a drawing or specification that indicates one way or another?

Or are you speculating as I am?

Thanks, Dave.

[Robert Lees]

Re: aileron pulleys

My word...it's a good thing we have the archive facility available. Well researched.

Yes, I am speculating, Dave, but on a learned basis. I agree that I have seen no technical drawings from Taylorcraft that specify one way or the other.

I do know that hub bushings are traditionally and generically an interference fit into their pulleys, and in this situation are usually wider than the pulley (where the "axle" is retained in a "bearer").

In wear terms, pulleys are usually "sacrificial" to cables ; bushings are usually "sacrificial" to the pulley, and in our case, where bolts (axles) are easily replaceable, these are "sacrificial" to the bushing, although in close-tolerance, highly-ground and expensive axle situations, this might be reversed.

Also, we know that all AN bolts are under-size (suggesting that lubrication is immediately adjacent to the bolt OD).

A Shilling to a pinch of elephant dung that I'm right. All wagers accepted; the loser donates winnings to the charity of the winner's choice.

Rob

[Guest]

Re: aileron pulleys

Hey Rob, thanks.

I have only seen t-crafts newer and older, probably only four or five different planes with the bushing loose in the pulley and rotating there upon.

I understand all the things you mention that are traditional good design practices. I also suspect that many of the pulleys that forum members have devised or purchased are superior to what I percieve as the intended design.

But then traditionally designers don't put a metal bar thru the middle of a door frame or put the side window's top edge below the average person's sight line or make you remove the engine to change the exhaust.

So I am ready to believe anything!

Dave

[dedrekon]

Re: aileron pulleys

Rob,
I don't know how things work over there in ye olde countre, but charities here have established a "no elephant dung" rule. They'll doth accept nary a pinch, no matter how magnanimous the intentions of the bequeather.




cheers,

v

[Guest]

Re: aileron pulleys

I was really hoping to win the schilling instead!