View Full Version : Tail Hub Slop
Hi This topic is only about the tail.
I have an old intrepid gasser with a tail hub ID of 5.05mm Tail output shaft is 5.00mm The hub rocks on the single hub setscrew installed. I think this contributed to the tail pitch slider breaking on a previous flight, but for now it locks up the tail intermitantly. When it rocks at the hub it changes the geometry of the pitch links & allows binding. Anyone else have this issue?
Also:
1) Does PN 231 the $125.95 blade grip kit have the offset pitch arm? What all comes in this kit?
2) Does PN 231A (1) grip have the offset arm as well & can it use the thrust bearings in my old grips?
3) Do I need new type pitch links with the new type grips & offset pitch arms.
4) What are PN 231B Grip Spacers there is no mention in my manual for this part, How are they used / installed?
Thanks all.
As an update... I spoke to Chris on the phone & he advised to ensure the set screw was tight in the dimple of the tail shaft, I thought this was done... oppps that fixed the hub issue but the binding remains. So I removed the long pitch rod & put the blades horizontal, & moved the lever by hand...way smooth. Then rotated the blades 180 deg then the binding happened, :arggg: So you say, the shaft is bent, I don't think so cause, I marked the foward blade when there was no binding & removed the hub & blade assy & put the blades on opposite sides ultimately exchanging the pitch links & blade grips with the other. Now the binding was happening with the unmarked blade forward. :arggg: :arggg: Which leads me to believe there is something up with either the grips or the pitch links or hub axel, any thoughts anyone??
cbergen
07-25-2006, 08:59 AM
Possibly the thrust bearings themselves.
Look for "pitting" in the races, ensure the smaller ID race is to the outside, and lubricate them with a good grease.
Do you have the slight amount of in and out play on the blade grips?
Malorie
07-25-2006, 09:19 AM
Let's back up a minute here.
Where is the binding? Could you give us a better discription? Is it binding when you try to operate the T/R bellcrank by hand? I guess what I'm saying is I'm confused. LOL
The best way to troubleshoot the tail system is to look at the individual parts. Do the bladegrips, when disconnected from the pitch slider, rotate freely on the hub axle? Do the pitch links on the bladegrips pivot freely when disconnected from the pitch plate? Does the pitch slider move freely on the output shaft when disconnected from the bladegrips and the T/R bellcrank? Does the T/R bellcrank rotate freely on the pivot when disconnected from the pushrod and pitch slider? Are both the output shaft and tail hub straight?
If all that is true, then look for things that would change under load, namely the thrust bearings. Are they notchy (you can typically only tell this by visual inpection BTW). Are the radial bearings in the bladegrips smooth?
There's only so much that could possibly be wrong, so work your way through the individual parts and I'm sure you'll track down the issue. :)
Malorie
Yes Chris the slight axial play is present at the grips. Malorie I'll do as you say on each item, your right I should find this. Chris hold off on my parts order until you hear from me on this issue, (unless they've already gone out !
Thanks alot for your help (again!)
FINALLY !! :lol: I found it by checking & isolating :oops: Normal maintenance practices Oh well sometimes you can't see the forest for the trees!! The new pitch arm that Chris so kindly provided needed to be shimmed a little farther away from the holding arm. This allows the ball on the pitch slider a little more movement. It's just enough now that it's not binding. I also cleaned up the bore of the sliding sleeve, that may have helped to. So I don't need the tail hub in my order Chris but no big one if you already sent it out...you guys are so fast at doing that!!
Thanks for all your help.
Helisin
08-02-2006, 01:06 AM
I just finished the tail set-up on my EB and found a lot of binding. Too much thread locker on the pivot plate arm eyelet...and bolt :oops: Remedied that and is still a very minor binding which I believe is between the slider and output shaft. Will play more tomorrow. Even whith the current pitch arm tightened right up, there is slop in it but can't feel any binding. Want to phone and order the new tail pitch arm tomorrow as well.
RS
Malorie
08-02-2006, 06:21 AM
Check the hex on the ball on the pitch slider to be sure it isn't hitting the cup thoughout the pit range. Also check the fit of thay ball in the cup. :)
Malorie
It was the ball hex that caused my binding. Malorie, can the cup be squeezed to fit tighter on the ball? I seem to have more play there than I like.
cbergen
08-02-2006, 09:43 AM
The delrin insert is replaceable, unscrew it and put a new one in it's place.
Helisin
08-02-2006, 10:18 AM
Check the hex on the ball on the pitch slider to be sure it isn't hitting the cup thoughout the pit range. Also check the fit of thay ball in the cup. :)
Malorie
The hex on my pitch slider ball is a long way from contacting anything. Atleast 1/8". The ball sits so that it is just below the surface of the delrin insert. Are there different depth delrin inserts? I will try a little motion lotion on the ball/delrin. Thanks for all input. Ha! no pun intended :D
RS.