Bungee spring Item 109-1, P/N 9910 for 14-13-2

artL

artL

New member
Hi, all,

I have been searching for control cable tensions for rigging purposes on a 1947 Bellanca Cruisair 14-13-2. I thought I had the best information available from a compilation of several previous posts, and came up with (30# +4/-2) for the rudder cables. The problem is, the cable tension is actually set by the bungee spring shown on plate 109 item 1 in the parts manual. I ran out of threads in the turnbuckle assembly and only reached 12 lbs tension. So, my question is does anyone have information as to the tension of the bungee spring part number 9910 in the original installation. Are my springs weakened after 67 years of service? Or is this the approximate original pre-tension?

The second part of the equation is that Bellanca drawing 15085 shows a 30# initial tension on the tail wheel steering spring which is a part of the overall assembly, and is incorporated in the rudder rigging.

I'm trying to get unconfused and any help would be appreciated.



Thanks to all,
art
 
watching this thread with interest.

#30 sure sounds like a lot of tension.
maybe at full deflection to one side.. but static tension..??
:?:
 
Blimby, you are correct - the static rudder cable tension is set by the spring (Ref Parts Manual Plate 109, Item 109-1, p/n 9910) which connects the bellcrank (Items 109-2 & 109-9, p/n 9817) to the firewall structure in the cockpit. Plate 109 only depicts 1 spring, but there is one each connected to each bellcrank. In my airplane that spring provides about 10 lbs. cable tension. The rudder cable is directly connected between the bellcrank at the rudder pedal and the control horn at the rudder post. The turnbuckle at the rudder post adjusts the length of the rudder cable (about +/- 1") which in turn adjusts the position of the rudder pedals fore and aft in the cockpit. The turnbuckle at the rudder post does not adjust the rudder cable tension as I had first thought. When the tailwheel is lifted off the ground and the rudder pedals are centered, then the rudder should be centered. Any movement at the rudder itself is taken up by the (p/n 9910) springs. If you were to push forward on both rudder pedals simultaneously, only then would you be increasing the tension on the rudder cables.

In an earlier post I had mentioned that I experienced a master brake cylinder piston rod failure last year. As I have been going through the 2 boxes of paperwork that came with the airplane, I found a Bellanca Service Bulletin #17 which addresses this type failure, and recommends rigging the rudder pedals aft by adjusting the turnbuckles at the rudder post control horn. It is worth reading.

So far, all of this is starting to make sense. When I took delivery of the airplane, the rudder control cables were slack, the tailwheel steering cables were slack, the rudder pedals were rigged forward, and the steerable tailwheel was very difficult to move. This comes together to help explain why I had difficulty maintaining directional control on taxi and on roll-out. At least I have a reason other than rusty piloting skills!

The 30# tension idea came about from the note on Bellanca drawing 15085 which calls out "30# initial tension extension spring". This particular spring (Ref Plate 117, Group B, item 117-4, p/n 15085-21) is part of the steerable tailwheel rigging. It apparently acts as a shock absorber in the steering linkage. Looking at that drawing segment in isolation I inferred that (30#) as the rudder cable tension, not realizing that p/n 9910 spring was also part of the system. I think others have drawn that same conclusion based on some posts that I've read in the past.

I now have the rudder cables installed and the rudder pedals properly rigged. I will continue rigging the tailwheel steering.

N74221 has been in continuous maintenance mode since October 2014. I could write a short story on all of the discrepancies that I have found on an airplane that was fresh out of annual and had just been returned to service after more than 30 years in total restoration. Even though I should know better, I bypassed a pre-purchase inspection. Fresh annual? What could go wrong? Ha! Don't go there! While a pre-purchase would not have caught all of the things I have now discovered, it would likely have found enough wrong to negotiate a better price or walk away. Forget about relying on an annual inspection sign-off unless you know the person and reputation behind the signature.

Not complaining mind you; I have the time and place to work on it, an A&P license, and 50 years experience. But I'd rather be flying.
 
Art, the springs that tension the rudder cables are really just to keep out the slack. As far as the tailwheel cables, they are difficult to adjust since they are clamped to the rudder cable in a miserable spot at the rear of the fuselage. After several attempts at making my arms into pretzels, I cut inspection holes on both sides of the fuselage so that I could get wrenches/hands/eyeballs into the space. Getting the tailwheel cables adjusted evenly took a few tries and a bit of cussing. When I first got my Cruisair, it had very loose tailwheel cables and Cleaveland brakes with Scott master cylinders. A friend with over 2000 Cruisair hours flew it home for me, and had a hell of a time keeping it on the runway the first landing. He said not to fly it until it was sorted out. Much like yours, it was with a fresh annual. Proper cylinders and a few tries at adjusting the tailwheel springs and it is much better. Grant.
 
Thanks, Grant. I think I have it figured out now and everything you said agrees with my findings. Or my findings substantiate what you said. I posted something similar to Blimpy earlier today.

My best guess to adjust the tailwheel steering is to locate the sliding clamp at the dimension shown on drawing 15085 (6" +/- 1/2") and then pull the steering cable through the clamp so that the 30# tension spring is just snug. It seems to me that if there is more than 10# pulled on the tension spring, then the rudder cable segment between the clamp and the rudder post would go slack, whereas if there isn't any tension on the steering cable, then the tailwheel will be loose.

I agree with the access panels but I'm going to try one more time through the inspection holes.

For anyone reading this post, it seems to me that adjusting the rudder / steering cables is a 3 step process, and the order is important. 1) Tailwheel off the ground, 2) adjust the rudder cable length, 3) adjust the steering cable tension.
 
Thanks, this thread is good stuff. I think the info posted is spot on. Since my cruisair handled like a baby doll on the ground (as well as in the air), I never gave the rudder system much thought. Your average A&P might not either. Something for the maintenance check list.
ron
 
ArtL, thanks so much ! While my tail wheel control is fine... I am positive on of my rudder springs is weak
which makes for pretty unbalanced flying.

My plane has been down for a year... bad brakes, wing and fuse skin damage from bad brakes,
flooded hanger ( a theme ! ) and an ankle in a boot for months.

Patching is 90% done.. and the last of that will be done as part of the wing prep for paint.

Alerons and Flaps patched.

Ugliness on wings being fixed this week.. ( trying to beat the rain and cold.. which is coming).

New clevelands going on.. hell or high water.

No A&P and no 50 years exp.

Down to dan torrey.. and he and I will give the rudder rigging a REAL close look !
Thanks for the info !
 
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