aileron pulleys

[Ron Greene]

Re: aileron pulleys

I sure thought Robert was correct and had discussed this with my IA in the past and he agreed with Robert also.

I just looked at drawing A-228 (Pulley 3" Control Cable) and A-229 (Pulley 1-3/4" Control Cable) and the dimension given for the center hole was .380 inches plus .002 and minus .001. I then looked at drawing A-920 (Pulley-Bushing) and it gave an outside diameter of .3765 inches plus .000 and minus .001 Based on that and if I did my math right the bushing would be loose on the pulley.

The bushing length is .375 inches plus or minus .005 and the pulley thickness is listed as .3275 over .345

Ron Greene

[Falcon10]

Re: aileron pulleys

This thred has been very helpful for me !! I have been working on my 39 BC
trying to get the rigging correct. The pulleys from yoke sprocket to the alieron control cables are worn enough that these cables are loose. I want to reuse the original cables as they are in good condition. I like seeing the hand woven terminals rather than the "new style " Nico's. I will be shoping for the best price on the replacement pullys. I will try Ralmark and Taylorcraft in the am. Anyone have any recent experence with the taylorcraft factory. I am going to have to replace my lower cowl pretty soon and they are showing some in stock. Will they do C.O.D.?
Thanks.
Jim

[Guest]

Re: aileron pulleys

Hey Ron, thanks, some actual data great! Thanks for looking it up.

Question, the bushing dia. of .3765 +/- .005 any chance that a "0" got left off somewhere when you typed it?

Reason I ask is its a 4 digit spec. and a 3 digit tolerance and I would have guessed a 4 digit tolerance. Just a guess on my part.

The nominal tolerance (.380-.3765) is .0035 loose. So the expectaion is that the parts will fit loose.

Now that I have these numbers I know that I am going be thinking about statistical tolerancing, that's a 20 year old memory.

eek! my head hurts already!

Thanks again, Dave.

[Ron Greene]

Re: aileron pulleys

I apologize, I went back to the drawing to check the tolerance for Dave and noticed the length of the bushing tolerance was plus or minus .005 and for the actual bushing tolerance it was plus .000 and minus .001 Corrected text below;

I sure thought Robert was correct and had discussed this with my IA in the past and he agreed with Robert also.

I just looked at drawing A-228 (Pulley 3" Control Cable) and A-229 (Pulley 1-3/4" Control Cable) and the dimension given for the center hole was .380 inches plus .002 and minus .001. I then looked at drawing A-920 (Pulley-Bushing) and it gave an outside diameter of .3765 inches plus .000 and minus .001 , based on that and if I did my math right the bushing would be loose on the pulley.

The bushing length is .375 inches plus or minus .005 and the pulley thickness is listed as .3275 over .345

Sorry for the confusion,
Ron Greene

[NY86]

Re: aileron pulleys

I'm no expert on T-craft airframe stuff, but I've seen plenty of pulleys from that era with a steel bushing that is a loose fit and longer than the pulley width. Said bushing is clamped firmly in the pulley bracket with a fiber stop nut and bolt, so the bushing cannot turn and the pulley must turn on the bushing. My bet is the T-craft design is no different...

[Forrest Barber]

Re: aileron pulleys

IF the "bushing" actually an axle is longer than the width of the pulley then when you tighten the bolt then the axle is held from moving and the pulley rotates on this axle "bushing" . thats the way C.G. intended it to be.....
drawing being found now.

[Guest]

Re: aileron pulleys

IF the "bushing" actually an axle is longer than the width of the pulley then when you tighten the bolt then the axle is held from moving and the pulley rotates on this axle "bushing" . thats the way C.G. intended it to be.....
drawing being found now.

Forrest,

Ron Greene has already looked up the drawings A-228 and A-229.

See above

Dave

[Forrest Barber]

Re: aileron pulleys

thanks , I was going to confirm with the "Inspection" set we have here rather than the micro film , I am sure they are the same....