VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 05-22-2020, 09:00 AM
Loman Loman is offline
 
Join Date: Feb 2008
Location: Dublin, Ireland
Posts: 173
Default Elevator Control Stick limits

I began evaluating a new (1.25in deeper) instrument panel today. I fitted the blank for the first time and expected to see bad interference between stick and panel in the full nose down stick position. Instead, the top of the uncut stick only came to barely 1.5in from the panel face. That's fine but....

Is this normal?

I don't think so. So I began looking for interference. There appears to be nothing hitting any part of the control linkage right back to the elevator bell crank. The larger aft control arm is not currently fitted so the elevator stops at the tail are not coming into play.

I cant even see what is limiting the fore-aft stick movement in the absence of the elevator stops at the tail. There appears to be air all around all moving parts of the system throughout its entire range of movement.

Does anybody know what the limiting factor is on control stick movement in the absence of the normal stops at the tail?

The link below goes to a photo below showing my fat hand grasping the uncut stick in the full forward position. I couldn't embed it despite the very clear instructions.

https://lh3.googleusercontent.com/pw...-no?authuser=0
__________________
Loman O'Byrne
RV9 TU. O-320-E2D. Engine hung, working on panel, Arklow, Ireland
=VAF= dues paid through Dec 2020

Last edited by Loman : 05-22-2020 at 09:01 AM. Reason: correct dimension
Reply With Quote
  #2  
Old 05-22-2020, 09:24 AM
Mel's Avatar
Mel Mel is online now
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,556
Default

You'll have to show pictures of the mechanism for anyone to find the problem. Something has to be hitting something to stop the travel. My first guess would be the stick hitting the forward edge of the seat/spar cover cut-out.
__________________
Mel Asberry..DAR since last century
A&P/BGI/EAA (LifeTime) Tech Counselor/Flight Advisor/Nat'l Test Pilot School
Specializing in Amateur-Built and Light-Sport Aircraft
<rvmel(at)icloud.com>
North Texas (8TA5)
RV-6 Flying since 1993, 172hp O-320, 3-Blade Catto (since 2003)Sold
Legend Cub purchased 12/2017
FRIEND of the RV-1
Eagle's Nest Mentor
Recipient of Wright Brothers "Master Pilot" Award
Reply With Quote
  #3  
Old 05-22-2020, 09:48 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 779
Default

Maybe going at this backwards? Shouldn't you be putting in the control stop in the tail, adjusting elevator for max up/down movement per section 15 in the manual... than adjusting the linkage for stick movement limits/interferences?
__________________
Ralph
It's time to work on just my own planes, not everybody else's...
Reply With Quote
  #4  
Old 05-22-2020, 10:05 AM
terrye terrye is offline
 
Join Date: Feb 2010
Location: Vancouver, BC, Canada
Posts: 826
Default Elevator Control Stick limits

I tried to do this a while back for the same reason, deeper panel. I tried to take measurements from the 1/4 scale fuselage drawing, knowing the up and down elevator angle limits in the manual and working backwards through the linkage and assuming the angle of the stick on the drawing was the design neutral position. This was inconclusive. I then emailed Vans and asked what the design stick angles were for neutral, full up and full down, but they were unable to supply this information.

So it appears a full mockup or an actual installation of the control linkage and elevator is required to resolve this.
__________________
Terry Edwards
RV-9A (Fuselage)
2019/2020 VAF Contribution Sent
Reply With Quote
  #5  
Old 05-22-2020, 10:27 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 779
Default

"... than adjusting the linkage for stick movement limits/interferences? "

The stick adjustments in all the RVs I've encountered varied a bit in neutral position dictated by panel clearance (some had lower panels, some higher) and pilot's arm length. Generally I start with neutral being perpendicular to the spar cap for SbS models, than adjust from there. Some RV-8s had the forward stick limit so far forward I couldn't reach it's stop when strapped in (those pilots were built like apes I guess)... Again, the elevator down stop must be there to fix the forward max motion. Also, depending on the stick grip you decide to go with- further adjustment will be required for clearances.
__________________
Ralph
It's time to work on just my own planes, not everybody else's...
Reply With Quote
  #6  
Old 05-22-2020, 11:05 AM
Mel's Avatar
Mel Mel is online now
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,556
Default

Everyone is different. Because I have short legs and a fat belly, I adjusted my controls based on down travel as far forward as possible and other adjustments from that datum. I also shortened my sticks considerably and never had a problem in over 25 years of flying it.
__________________
Mel Asberry..DAR since last century
A&P/BGI/EAA (LifeTime) Tech Counselor/Flight Advisor/Nat'l Test Pilot School
Specializing in Amateur-Built and Light-Sport Aircraft
<rvmel(at)icloud.com>
North Texas (8TA5)
RV-6 Flying since 1993, 172hp O-320, 3-Blade Catto (since 2003)Sold
Legend Cub purchased 12/2017
FRIEND of the RV-1
Eagle's Nest Mentor
Recipient of Wright Brothers "Master Pilot" Award
Reply With Quote
  #7  
Old 05-22-2020, 11:11 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 779
Default

Yeh, my belly clearance influences my stick adjustments too... sadly.
__________________
Ralph
It's time to work on just my own planes, not everybody else's...
Reply With Quote
  #8  
Old 05-22-2020, 04:15 PM
Loman Loman is offline
 
Join Date: Feb 2008
Location: Dublin, Ireland
Posts: 173
Default Mel came closest

It was the upper edge of the seat/spar cut-outs through which the F-665 pushrod moves, linking the movement of the two sticks . Don't know how I didn't see that.

For clarity, years ago, when I trial fitted the elevators, I adjusted the control linkages to give a vertical stick with the elevators in trail. The project has moved location since and was fully disassembled. I am now getting back to where I was back then. In retrospect, maybe I should have adjusted the sticks to the middle of their travel (allowing for belly clearance) instead of simply vertical, with the elevators in trail.

The question I am working on now is what is the maximum length the sticks can be before hitting my thumb while passing under the panel lower edge and is that length reasonable? If it feels too short, then I can't live with a panel that deep and the layout is going to have to change.

To find out for sure, I think I am going to have to temporarily reassemble and rig the elevators again as Terrye says. Then I can see if I need to increase the size of those seat rib cut-outs and also determine the final length of the sticks.

Thanks for all the replies
__________________
Loman O'Byrne
RV9 TU. O-320-E2D. Engine hung, working on panel, Arklow, Ireland
=VAF= dues paid through Dec 2020
Reply With Quote
  #9  
Old 05-24-2020, 12:56 PM
n82rb's Avatar
n82rb n82rb is offline
 
Join Date: Jan 2007
Location: fort myers fl
Posts: 902
Default

be careful about deeper panels. you will have to cut the stick and then everbody will know that you have a short stick!
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 05:29 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.