As some may recall from a recent post, one of the forward stabilator trim cables unwound from the drum in flight on my Seneca II. The consensus was that the unwinding was caused by insufficient cable tension.
After winding the cable around the drum and after a short flight, the cable tension was about 8 lbs. The ambient temperature at the time was 82 degrees F. According to the Seneca II Service Manual, the tension on the stabilator trim tab cable should be 10lbs +/- 1 lb. The Manual further states that cable rigging tensions should be corrected to ambient temperature in the area where the tension is being checked using Table V-II. That Table is attached to this post.
The Table makes no sense to me. As an example, according to the Table, if the ambient temperature is 20 degrees F., the adjustment would be to subtract 10 lbs. which would leave no tension. That obviously is not right. Am I missing something?
As a further example, assuming a temperature of 90 degrees, the Table calls for an adjustment of 4 lbs. to the stabilator trim tab cable which would constitute a 40% increase in tension. By way of comparison, a 4 lbs. adjustment to the stabilator cable (as opposed to the stabilator trim cable) would only constitute an approximate 13% adjustment based on an unadjusted setting of 30 lbs.
Again, what am I missing?
View attachment Table V-II.pdf
After winding the cable around the drum and after a short flight, the cable tension was about 8 lbs. The ambient temperature at the time was 82 degrees F. According to the Seneca II Service Manual, the tension on the stabilator trim tab cable should be 10lbs +/- 1 lb. The Manual further states that cable rigging tensions should be corrected to ambient temperature in the area where the tension is being checked using Table V-II. That Table is attached to this post.
The Table makes no sense to me. As an example, according to the Table, if the ambient temperature is 20 degrees F., the adjustment would be to subtract 10 lbs. which would leave no tension. That obviously is not right. Am I missing something?
As a further example, assuming a temperature of 90 degrees, the Table calls for an adjustment of 4 lbs. to the stabilator trim tab cable which would constitute a 40% increase in tension. By way of comparison, a 4 lbs. adjustment to the stabilator cable (as opposed to the stabilator trim cable) would only constitute an approximate 13% adjustment based on an unadjusted setting of 30 lbs.
Again, what am I missing?
View attachment Table V-II.pdf
