Culver Cadet Section > Culver General Discussion
GEAR FAILURES AND HOW TO AVOID THEM
Paul Rule:
The Cadet was one of the very first production airplanes with retractable landing gear and that has clearly been a problem area. I do not know of any Cadet that has not been on it's belly at least once. Maybe someone will post the exception here but I doubt it. This thread is to share some of the reasons for gear problems and maybe prevent a few gear-up landings in the future.
I think gear problems can be catigorized, at minimum, as follows (maybe you will want to add to the list):
1. Forgetting to put it down. (The warning system should prevent this ... if its working and we are paying attention.)
2. Having some mechanical failure with no warning.
3. Putting it down and thinking it is locked when it's not. (Not understanding how it works...?)
4. Having the gear unlock after putting it down and locking it. (Lever slips out and gets pushed to right by your leg.)
5. Inadvertently bending something by letting the gear fall when extending (and then the pins don't go in).
6. Something (push rod system) gets bent inflight due to high "Gs" and the pins won't go in when you extend.
As I look at the list, I believe that it is in REVERSE ORDER of most likely to happen !! My experience and conversations with several others is that the threaded ends of the push rods (can and will) bend a little and (if you are lucky) you notice that the pins have become harder to lock in. Being a prudent (and suspicious) sort you then inspect and find the culprit before it bends more on the next flight and the pins refuse to lock. Culver service memorandum no. 1 dated 10-24-41 still applies and is GOOD info. On page 2 it says; "To neglect the warning implied by stiff operation is to invite trouble."
There have been a number of ideas on how to make the push rods more rigid and less likely to cause problems including making new ends with 7/16" threads in place of the standard 3/8". The factory part is made from 4130 thick wall tubeing. It is interesting to note that a tube is more rigid then the same sized round solid part. Since many have been replaced with fabricated parts this may not have been noticed.
This ought to start some good discussion.
Paul Rule:
I'll add a drawing I did years ago for the "Culvers Going Places" mag:
Woody:
I have logs from the day N37823 (373) rolled out of the factory. There is nothing that I can find of any damage or accident of any kind on this plane. Maybe I don't know where to look but it appears to have been recovered only once in 1954 with a change in color from red to green. Since 1964 it was hid away in a hanger in Fl. needing to restore.
Paul Rule:
Woody, I hope you have "The One" !! Sometimes it's hard to find... do the pushrod ends look original and identical?? Are they made from tube stock? Any log entry where the prop and/or exhaust stacks (or pitot tube or carb air box) were replaced with no reason given? Some Cadets settled onto their bellys very gently.... If you have the expander brakes are the light weight metal covers over the brakes bent, damaged or repaired on the bottom? If a gear folds out toward the wing tip it gets the plywood nose rib next to it and it's often repaired not replaced.
Hope you find none of this!!! P.R.
Woody:
Breaks and such were in great shape with NO rust. It had expander brakes but I did not feel safe with them. Push rods are solid with I think 3/8" ends. Everything still had the green primer on it even though it was removed and repainted. There was no repair work on the spar etc. Some trailing edges had to be replaced from dry rot only. Dry rot was on one the right wing spar at the wing root which was cut out (1 inch) and replaced which is in my pictures on web site. This plane only has 530 hours on airframe which I guess helps.
From reading the comments, I sure want to make sure the pins on the ratchet system gets enough bite and seats right. I'm learning a lot from everyone.
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