The International Cessna 170 Association

Gents,

I have completely replaced the cables and pulleys using (the correct) McFarlane kits. I have the aileron direct cable turnbuckles cranked to the max and have just barely enough tension. If (When) they stretch they will fall below aceptable tension. I removed the new cable and compared it to the one I'm replacing. It is the same length. I can replace the fork fitting at the wing bell-cranks with shorter ones, but I want to understand why I'm having the problem, rather than work around it.

The trim cable is even worse. I cannot get enough tension on it. The trim system works; it is rigged correctly, but the tension is inadequate. I can shorten the cable at the disconnect, but again I'm looking for any experience you've had with this in case I'm missing something.

Has anyone else has had similar problems when replacing cables?

Thanks,

Gareth

P.S. This is the last snag on my inspection list. Engine and taxi tests have been successfully completed. Once this is solved, there is only paperwork remaining before flight. Pictures will follow!

Gareth, maybe a red herring, I see there’s two pulleys with a different part number than the rest. Looks like the four in the vertical runs are the same, the two inboard wing might have a larger inside diameter. Guess I’m asking do you have all the right pulleys?

Gareth,
If Jim's idea of confirming pulley size doesn't find any discrepancies, you might confirm that you have the correct turnbuckle barrels. They come in long and short lengths. The short barrel is 2-1/4" long and the long one (AN155-32L) is 4" long. For the aileron system the only short barrel - AN155-32S - (S for short) is found on the control tee (fig. 42-6). If necessary, I suppose you could replace the long barrels which are called for in the IPC with short ones, but I agree with you that it is important to get to the root of the problem before making such corrections. Might be worth a call to McFarlane to explain your problem and get the specs for the length of these cables.