|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

07-05-2012, 06:39 AM
|
 |
|
|
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
|
|
Quote:
Originally Posted by Flying Scotsman
Installing elevator pushrods tomorrow...just to confirm that there is no measurement other than "vertical" on the elevator bellcrank? I believe that on the -8 there is a measurement called out somewhere, but I couldn't locate any such measurement on the -7 plans.
|
Correct, there's no measurement other than vertical on the elevator bellcrank. The elevator, of course, should be in trail at the time this is set. No other measurement needed in this case.
The other thing here is there should be NO way for any rod end bearing on that push tube to come off if more than half the threads on each rod end bearing are engaged.
|

07-05-2012, 07:57 AM
|
|
|
|
Join Date: Nov 2005
Posts: 1,256
|
|
Quote:
Originally Posted by LettersFromFlyoverCountry
Correct, there's no measurement other than vertical on the elevator bellcrank. The elevator, of course, should be in trail at the time this is set. No other measurement needed in this case.
|
Thanks...that's what I needed to know.
Quote:
|
The other thing here is there should be NO way for any rod end bearing on that push tube to come off if more than half the threads on each rod end bearing are engaged.
|
Yep...see my post #10 just above 
__________________
Steve "Flying Scotsman"
Santa Clarita, CA
PP-ASEL, ASES, Instrument Airplane
RV-7A N660WS flying!
#8,000
|

07-05-2012, 08:09 AM
|
 |
|
|
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
|
|
Also make sure that the jam nuts are tight before you drop the pushrods in. Not so much with the big rod but with the smaller one that goes forward, it's a giant pain in the neck to get a wrench in there to do it once it's been installed.
I know this is a "duh" advisory, but it's surprising how many times DARs and others find these particular jam nuts loose.
|

07-05-2012, 11:45 AM
|
|
|
|
Join Date: Jan 2011
Location: Cumming, Georgia
Posts: 873
|
|
ROd ends
It should almost be impossible for any pushrod on a Vans aircraft to unscrew it's self since all the rod ends are threaded like a normal bolt and not like a turnbuckle. You can not turn the pushrod and have both rod ends loosen up.
Smilin' Jack
Ever wonder if you've been building too long... and now might have an answer 
__________________
Smilin' Jack & Anita Hunt
N507H RV7, KJZP Jasper, GA
EAA690
APRS/ WB4JKY
Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
Hunt Aviation, LLC.
Pilot Service, IPC's Biennials.
Comm Glider
|

07-05-2012, 01:10 PM
|
 |
|
|
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
|
|
Quote:
Originally Posted by Smilin' Jack
It should almost be impossible for any pushrod on a Vans aircraft to unscrew it's self since all the rod ends are threaded like a normal bolt and not like a turnbuckle. You can not turn the pushrod and have both rod ends loosen up.
|
Actually it is possible (just not in the way you think).
Since both rod ends are threaded as you describe, if they are both loose and rotating, the push/pull rod would be threading further onto one while it is threading further off the other. The way RV push/pull rods are designed, they should always bottom out onto the jamb nut of the one threading further in, before they fully unscrew off the rod end that is threading out.
|

07-05-2012, 05:30 PM
|
 |
|
|
Join Date: Mar 2005
Location: Dallas area
Posts: 10,769
|
|
Never say Never!
Quote:
Originally Posted by Smilin' Jack
It should almost be impossible for any pushrod on a Vans aircraft to unscrew it's self since all the rod ends are threaded like a normal bolt and not like a turnbuckle. You can not turn the pushrod and have both rod ends loosen up.
|
Anytime you think something can't be done or is "almost impossible", I promise, SOMEONE will prove you wrong.
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
|

07-06-2012, 04:02 PM
|
|
|
|
Join Date: Nov 2005
Posts: 1,256
|
|
Quote:
Originally Posted by rvbuilder2002
Actually it is possible (just not in the way you think).
Since both rod ends are threaded as you describe, if they are both loose and rotating, the push/pull rod would be threading further onto one while it is threading further off the other. The way RV push/pull rods are designed, they should always bottom out onto the jamb nut of the one threading further in, before they fully unscrew off the rod end that is threading out.
|
This depends critically on the length. I was a) careful to make all pushrods to the *exact* length per the plans and b) double-checking each pushrod as we assemble the systems to check for possible backing-out problems (none found so far).
__________________
Steve "Flying Scotsman"
Santa Clarita, CA
PP-ASEL, ASES, Instrument Airplane
RV-7A N660WS flying!
#8,000
|

07-06-2012, 08:06 PM
|
 |
|
|
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
|
|
Quote:
Originally Posted by Flying Scotsman
This depends critically on the length. I was a) careful to make all pushrods to the *exact* length per the plans and b) double-checking each pushrod as we assemble the systems to check for possible backing-out problems (none found so far).
|
I guess I should have clarified that if built correctly per plans, it should not be possible.
My post was in response to the comment that it wasn't possible because of the way the rod ends thread, but in reality, if the push/pull rod is of incorrect length, with the wrong amount of thread engagement of the rod ends, it is possible for the tube to thread to one end and separate from the rod end at the other end.
|

07-07-2012, 08:39 AM
|
 |
|
|
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
|
|
Quote:
Originally Posted by rvbuilder2002
I guess I should have clarified that if built correctly per plans, it should not be possible.
My post was in response to the comment that it wasn't possible because of the way the rod ends thread, but in reality, if the push/pull rod is of incorrect length, with the wrong amount of thread engagement of the rod ends, it is possible for the tube to thread to one end and separate from the rod end at the other end.
|
I would be very careful about assuming that just building the tube to the exact dimension will eliminate a problem. There are other factors here including how the elevators horns are installed and drilled, for example. If you're off by a 1/8", that pretty much negates the safety of the cut-to-plans push tube. Same with the bellcrank (although I can't recall if that's pre-drilled or not).
There's a reason why in dealing with rod end bearings -- of any kind -- the wisdom has always been make sure AT LEAST half the threads are engaged at both ends. That's the only foolproof guarantee, and it's just good building practice.
That's not to say other methods don't include a margin of safety.
|

12-30-2012, 08:50 PM
|
|
|
|
Join Date: Mar 2009
Location: Arvada, CO
Posts: 118
|
|
Interference
So the large and small pushrods are of the correct length, bellcranck verticle, etc... Problem is,the stick hits the instrument panel when full forward!! Not good...what to do?? Shorten sticks, extend elevator stop, or ??? Anyone else have this issue?
Jim
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 08:10 AM.
|