VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 02-14-2013, 09:56 PM
digidocs's Avatar
digidocs digidocs is offline
 
Join Date: Apr 2007
Location: -
Posts: 544
Default Use a cotter pin here?

The plans show a elastic stop nut on this big bolt, but the bolt itself is serving as the pivot. Can't really crank it down either because it would lock up the bellcrank.

Shouldn't this be a cotter pin situation?

Reply With Quote
  #2  
Old 02-14-2013, 10:01 PM
Greg Arehart's Avatar
Greg Arehart Greg Arehart is offline
 
Join Date: Jul 2007
Location: Delta, CO/Atlin, BC
Posts: 2,435
Default

I believe that there is a bushing around that bolt that is slightly longer than the hole in the weldment. When you tighten the bolt, it bears on the bushing, not the weldment. Thus, the weldment is relatively free to move around the bushing. Check the install instructions, as I'm not absolutely certain of this.

Greg
__________________
Greg Arehart
RV-9B (Big tires) Tipup @AJZ or CYSQ
N 7965A
Reply With Quote
  #3  
Old 02-14-2013, 10:40 PM
digidocs's Avatar
digidocs digidocs is offline
 
Join Date: Apr 2007
Location: -
Posts: 544
Default There is a bushing

Hi Greg,

You're right that there is a bushing. Mine are extremely tight in the steel bellcrank so all of the rotation occurs between the bushing and bolt. Do your bellcranks rotate on the bushing instead? Hmmn.

David
Reply With Quote
  #4  
Old 02-14-2013, 10:45 PM
DaAV8R DaAV8R is offline
 
Join Date: Jul 2009
Location: Lee's Summit, MO
Posts: 749
Default Ream and polish

You're going to need to ream the bellcrank or polish the bushing, or both. I spent a lot of time working on mine. With some effort you can make the bellcrank run silky smooth on the bushing.

I also had some trouble with the bellcrank dragging when the brackets to spar bolts were tightened. Some additional work fixed that problem as well.
__________________
Robert Williams
Lee's Summit, MO
RV-8 - Empennage & Wings Done
Working on Fuse
O-360-A1A

1946 Cessna 120
Reply With Quote
  #5  
Old 02-14-2013, 11:37 PM
OLDSAM OLDSAM is offline
 
Join Date: Feb 2008
Location: Tucker GA
Posts: 190
Default Do whatever it takes

Do whatever it takes to tighten the bolt properly so that the bushing is clamped between the brackets and cannot turn on the bolt.
The bellcrank must turn on the bushing, not the bushing on the bolt. The bushing has to be made a little longer than the bellcrank, as posted above, so the tightening of the bolt will not hamper the rotation of the bellcrank. Van's suggests a little light grease on the outside of the bushing for the bellcrank to spin on. Double check those directions and plans, it's in there.
__________________
OldSam
RV7A, Empennage, Wings & Tanks complete
Fuse under way
Reply With Quote
  #6  
Old 02-15-2013, 12:40 AM
digidocs's Avatar
digidocs digidocs is offline
 
Join Date: Apr 2007
Location: -
Posts: 544
Default

Thanks guys for pointing me in the right direction. I've got one bushing fitted and I'll work on the second tomorrow.

David
Reply With Quote
  #7  
Old 02-15-2013, 01:19 AM
roee roee is offline
 
Join Date: Feb 2006
Location: San Diego, CA, U.S.A.
Posts: 770
Thumbs up Get the bushing working right, AND use a cotter pin

As has already been said, make it so that the bushing fits properly -- bushing is held rigid when the bolt is properly torqued, and the bell crank rotates freely and smoothly around the bushing.

After having done all that, it's still not a bad idea to use a drilled bolt + castle nut + cotter pin.

This is a nice safety measure, just in case at some point in the future the bushing stops working properly due to gunk, or corrosion, or any other reason that would cause excessive friction between the bell crank and the bushing, which in the extreme case could cause the bushing to rotate.

This is improbable, and some will argue that a cotter pin arrangement is overkill for this situation. Maybe. But, so what? It's an extra safety measure on a safety-critical component, and it doesn't really cost you anything.
__________________
Roee Kalinsky
San Diego, CA, U.S.A.
RV-7A under construction
www.kalinskyconsulting.com/rvproj/
Reply With Quote
  #8  
Old 02-15-2013, 10:14 AM
jdeas's Avatar
jdeas jdeas is offline
 
Join Date: Mar 2006
Location: SoCal
Posts: 634
Default

Quote:
Originally Posted by roee View Post
After having done all that, it's still not a bad idea to use a drilled bolt + castle nut + cotter pin.
Just make sure you torque within spec then adjust washers to make the castle nut line up. Otherwise you are doing more harm than good by allowing the bushing to rotate!
__________________
JD
----------------------
RV-7 N314SY (KWHP)
IO-360-B1B
A&P


CANbus based trim/flaps and electrical
Reply With Quote
  #9  
Old 02-15-2013, 10:25 AM
Lemmingman's Avatar
Lemmingman Lemmingman is offline
 
Join Date: Jun 2010
Location: McKinney, TX
Posts: 689
Default

I have oriented my bolt so that if the nut were to fall off the bolt would remain in place. The nylon lock nut is more than sufficient for the task.
__________________
Gil Brice
McKinney, TX EAA-1246
RV7 - Working on fuse, fuel, brakes etc...
Reply With Quote
  #10  
Old 02-15-2013, 04:43 PM
roee roee is offline
 
Join Date: Feb 2006
Location: San Diego, CA, U.S.A.
Posts: 770
Default

Quote:
Originally Posted by jdeas View Post
Just make sure you torque within spec then adjust washers to make the castle nut line up. Otherwise you are doing more harm than good by allowing the bushing to rotate!
Yep. Like I said:

Quote:
Originally Posted by roee View Post
... make it so that the bushing fits properly -- bushing is held rigid when the bolt is properly torqued, and the bell crank rotates freely and smoothly around the bushing. ...
...
having done all that...
__________________
Roee Kalinsky
San Diego, CA, U.S.A.
RV-7A under construction
www.kalinskyconsulting.com/rvproj/
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 09:01 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.