stabilator cable tensioning

[ukey4917]

Here are some photos of my work on tightening the stabilatorcable. Earlier Mark B helped me identify the lazy stab when I described my lessthan spiffy lift offs.  I dived into thisand put a half gallon of water on the trailing edge and to check cable tension.Then I removed the seat and got busy to tighten up the rear turnbuckle.  Flown once since tightening.  (Not enough history so far to be reporting butI did have a total of maybe 10 take offs and landings (some being air hopsinitally)).  Now I have no movement with thehalf gallon water when the back stick is parked against the stop (using afabric strap to hold stick back for test).  I do not quite understand all aboutturnbuckles in that guidance says not more than three threads showing each end.It seems to me that the ends are able to turn in to the buckle so that nothreads show and even will recede into the buckle further (sort of like negativethreads showing) which allows more travel than I was expecting (a good thing).  Also, it seems that I may have had too muchtension on the other cable (now reduced) such that a sort of “pre-tension”existed that worked causing the half gallon to move the stabilator “pre-emptively”. Comments (except from Rahul) welcomed.
Gary Aliased

[mike_cummings2003]

Hi Gary Mike here
I like the 1/2 gallon of water idea, should work well. As for the threads
show no more than 3 is to insure that the is enough threads inside the turn
buckle to not pull out, No threads showing is fine.
Have you tried flying since readjusting the cables, should be a big
improvement.

--
Fly to live
Live to fly

[earthstaraircraft]

Hi Gary
Can you send better pictures. There dark and fuzzy, it's hard to see detail..
Do you have a builders manual?
If not send me an email asking for it and we will send one to via email no charge.
The up stop should be filed so that the stabilizer almost touches the rudder but has at least 1/4 in of clearance.
Both cables should be tight.
Take the stick and vigorously shake it for and aft as a test.
Happy Flying
Mark
Sent from my iPhone

[ukey4917]

Hi Mark, Ok, here are (what I hope to be) better pics.I have a manual but I will also ask for an email one so as to be sure I have the same one you are speak of.Thanks for the comment re the 1/4 inch. I am not at the hangar so I will check that next time.Both cables seem tight now. I am not so sure I understand the stick shaking method to determine stab cable tension.. (How all this came about was I found that the starboard eyebolt for the stabilator was a bit loose (found by forward and aft wiggling of the stab distal end.))As to flying I was seemingly not getting as much stab authority at min controllable airpeed (near touch down) as I would like. But that may be due my lack of deep experience (maybe 300+ touch downs so far) or general flying skill at keeping the gull in a more neutral landing attitude.. (Many landings are soooth kisses but sometimes I have sort of "clunk down" on t.d. So far I am attributing that to (1) loose eyebolt and (2) less than perfect cable tension.Gary

[blaswichk]

I found when properly tensioned, plucking it sounds like a low bass guitar sound, works for me with 510hrs on engine and airframe. I’m paying big bucks to “0” time my 503 with factory parts and factory trained engine builder. I love that combination so much. I won’t live long enough to wear it out again. No mods, just R &R the engine and go fly.

[blaswichk]

That is, just the stabilator. rudder cables are not as tight to allow proper nosewheel movement, (in my humble observation). Mark is the full answer man.

[ukey4917]

Kess,  I was followingthe MarkB as to the 5 lb load on the t.e. of stabilizer as indicative of cabletension. (thus the half gallon of water). During my amateur hour I could have tightened the “down” cable before Ifound the “up” cable turnbuckle (under the gas tank). All of which brings me tothe possible observation that the “down” cable tension (perhaps too  high) was introducing a “pre-load” that addedto the “lazy stab”.  Namely the smallestdown load on the t.e. of stab produced excess deflection (which may havedelayed lift off and left “nose up” wanting on t.d.).

Nothing more than suppositions and speculations at thispoint but I am grateful that Mark picked up this from such scant information onmy part. I have not taken my tuning fork for plucking around on the newlytensioned wires.

[ukey4917]

MarkB, here are some photos of the stabilator-rudder clearance. Looks about minimum to me. You mentioned 1/4 inch. (This is Gull 2000 with 20ft wing and 503 dcdi with 3 blade Powerfin prop (model not known for prop).