Control cable sizes

[170C]

George, you provided me with the cable tension for the cables (flaps, aileron, rudder & elevator). Can you give me the size of these cables? The cable tension tool specifies size in order to read correctly.
thanks

[GAHorn]

Frank, allow me to be didactic again for just a moment: If you are going to place a tensionometer onto a cable to check it's tension.... won't you be in a fairly good position to see what size it is? (There are more than one size cable in most airplanes. You have a 172, which I do not have an IPC for, and even if I did, it wouldn't list the cable sizes in your airplane.... it would only list part numbers.)

[blueldr]

Cables are usually found in fractional inch sizes and should be easily determined with even a machinists scale.

[170C]

George, I can check the sizes of the vrs cables by using my micrometer. I just thought that those values might have been published in one of the manuals you have that I don't. I would venture that the rudder cables in my plane are the same size (od) as the ones in yours unless when yours were replaced that larger or smaller ones were installed. I can see where possibly the original's might have been of a specified size and possibly if they were replaced with stainless steel ones or someone felt a slightly larger size was better that they might be slightly different. I would bet the farm (safe to say since I don't own one) that the 55-56 170B's, and maybe all B model 170's have the same size cables as do the 56-59 or so 172's. However, that is an opinion with no technical data to base it on, and we all know the value of opinions I'll ck my 172 IPC to see if it has cable sizes listed the next time I am in the hangar and remember to do so.

By the way George, when you were being didactic did that hurt

See ya in a couple of weeks in Grapevine!

[c170b53]

Frank you must have some time on your hands. The cables are adjusted (with the rudder in neutral) to displace the pedals a dimension from the firewall and (return) springs return the pedals to a neutral position providing tension. In other words do not be alarmed by low tensions in the rudder system. Probably the most important thing with respect to cables is to keep them clean. When cleaning them do not use solvents which will wash out the lubricants within the cables. One area that I have seen that needs attention is in the flap cables at the wing root as they exit the fuselage. There's a small panel atop the wing root that can be removed and which should be at annual to look at their condition.

[blueldr]

Does the C-172 have the same rudder pedal return spring system as the C-170? I'm curious, since it used to have a nose wheel steering system also connected to the rudder pedals.

[170C]

George do you have any knowledge regarding those rudder return springs? I don't , but would be of the opinion (here I go again with an opinion) that despite the fact my plane once had the training wheel on the front, that the rudder return springs are identical to later model 170 B's.

[Brad Brady]

George do you have any knowledge regarding those rudder return springs? I don't , but would be of the opinion (here I go again with an opinion) that despite the fact my plane once had the training wheel on the front, that the rudder return springs are identical to later model 170 B's.

Pokey,
Once again I'm not answering for George, But I looked up the springs for the 170, early 172 and the 175 They are ....170, Left...0310196-4 ...Right....3010196-3 The early 172, and 175 were the same.....Right...0310196-12 Left...0310196-5 It would seam to me that the DASH numbers are the only difference. I would imagine that the 170 numbers will superseded to the later numbers.....It's just that there is no difference in the three aircraft except the nose wheel on the 172 and 175.....other than that that are the same aircraft.....with the exception of the 175 having a "stepped" fire wall...

[GAHorn]

It's great when someone answers "for me"! Thanks, Brad! (I appreciate your courtesy, and want to assure you and everyone that I'm never offended when folks jump in and offer help/opinions/criticism/etc..... that's what these forums are for.)

Just as a matter of interest, the springs must not be the same and not superceded. Here's the result of the Cessna inventory search:
C-170
Order 0310196-3 SPRING
(List Price: $ 21.90) Stock Available $ 18.62 (EA)
Order 0310196-4 SPRING
(List Price: $ 14.50) Stock Available $ 13.05 (EA)

C-172
Order 0310196-5 SPRING
(List Price: $ 8.51) Stock Available $ 7.23 (EA)
0310196-12 SPRING
(List Price: $ 8.79) Stock Available $ 7.47 (EA)

But Frank's reason for having a converted 172 now becomes more apparent..... he's a cheapskate and was only saving a few buck when it comes time for replacement parts!

(Just for discussion: Keep in mind that the 172 has it's rudder circuits connected to the nosewheel steering thru push-pull rods. When the airplane is airborne the nose-wheel is centered via a cam so it remains aligned straight-ahead during touchdown, even if rudder is applied for a crosswind. This probably requires a different spring for reasons pertaining.

[170C]

Yea, when I found out I could save on similiar parts by doing a 172 conversion, I jumped on it George, you bring up an interesting point. Since my 172 has been coverted to a conventional gear, I am assuming it does have rudder return springs as does all 170's. Don't know if they are stronger or weaker springs than 170's or if the same. I have been fortunate not to have to change my thus far. Possibly some of the other 172 owners, with the conv. gear conversion can chime in.

[blueldr]

Strange. I thought Franks conversion was the only one here was.

[GAHorn]

Strange. I thought Franks conversion was the only one here was.

OK. Apparently the bar is open at bluEldr's.

[blueldr]

Unfortunately, I'm culturally deprived and without a bar. However, I've been giving a lot of consideration to building one ,if for no other reason than providing a suitable home for my five liter box of White Zinfandel Wine.

[170C]

I think this is the thread where George sent the photo from the '56 170B parts catalogue to me showing the control cables exiting the aft fugelage. George, my conversion only had the original rudder control cables existing from the aft fugelage. Those cables do double duty as they control the rudder as well a the tail wheel control. Don't know if this is a better or worse solution. I suppose on a 170 the tailwheel steering cable could, in an extreme case, break and you would lose tailwhee steering, but would still have rudder control and thus could still land without incident if you caught it soon enough.

[GAHorn]

Frank, the reason I sent you that particular pic ... was in response to your query regarding whether exit-fairings existed for rudder cables. (They do not. They do serve the late-model 170B tailwheel steering cables, however.)

This last post might indicate a slight misunderstanding you may harbor re: tailwheel steering. All 170's, 170A's, and 170B's up to SN 26505 used the rudder cables to operate the rudder directly, and tied the tailwheel steering, via steering chains/springs, to the rudder bellcrank.

Only beginning with SN 26505 were separate tailwheel steering cables installed to operate the tailwheel steering, by attaching them to the rudder cables with clamps, inside the rear fuselage.

Personal opinion: Cessna continued the design for the rest of the series because they'd already spent the money on engineering and parts. It does almost nothing for the actual steerability of the aircraft due to the "soft" nature of the Scott 3200 steering. But it does add complexity to the airplane, failure modes to the pulley's and bulkheads, and difficulty to the lubrication schedule of the airplane. ( It's "not worth a bucket of warm p---." - John Nance Garner)