VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #1  
Old 06-18-2018, 12:29 AM
RyanB RyanB is offline
 
Join Date: Sep 2017
Location: South Africa
Posts: 36
Default Tall Person mod

Hi Eveyone

I have done a lot of searching regarding moving the seat back on my RV4. I have just started building the fuselage so am trying to plan ahead.

From what I can find on the net most people just say move the roll bar back 1 to 1 1/2 inches, and this is where I get confused with the following:

1. Does one simply move the roll bar backwards, or must the F405 and F406 bulkheads also be moved as donít they give strength to the roll cage mounts?

2. Regarding the bottom of the seat, does one simply move back the seat back hinge?

3.Will the roll cage now interfere with the canopy frame, and if so how do we get around this?

4. Will the aft stick need to be modified to get full movement?

Sorry for all the questions but this mod is definitely something I need to start planning for.

Thank you for any help
Reply With Quote
  #2  
Old 06-18-2018, 04:29 AM
Michael Henning Michael Henning is offline
 
Join Date: Jun 2011
Location: Nashua, NH
Posts: 483
Default

I moved the roll bar back the maximum allowable distance (IIRC, 2”). The bulkheads stay I their original location. The bottom seat hinge moves back the same distance. No interference with the rear stick. If you try to go farther than plans allow, roll bar will interfere with canopy. I’m 6’2”, 34” inseam, and plane is comfortable on a 6 hour flight.
__________________
Mike
RV-4 #2750
N654ML
IO-360
WW150C Prop
1018 lbs
Flying
Reply With Quote
  #3  
Old 06-18-2018, 04:34 AM
RyanB RyanB is offline
 
Join Date: Sep 2017
Location: South Africa
Posts: 36
Default RV tall mod

Thanks Mike

That is great news and keeps it simple, I must just go relook at the plans as I couldnít find where it said anything about moving the roll bar back.

I am about the same height as you and also have the long leg problem, so this is great news.

All the best
Reply With Quote
  #4  
Old 06-18-2018, 04:48 AM
fixnflyguy fixnflyguy is offline
 
Join Date: Jan 2006
Location: Winston-Salem, N.C.
Posts: 917
Default What I did

First off, I don't know hall "Tall" you are, but I'm 6'1", tall to some, not very tall next to others. When I built mine, I had sat in a standard, per plans build RV-4, and had an idea what I would be comfortable in. I did not relocate, but slightly adjusted (AFT) the F405/406, but positioned the roll bar aft as far as possible without interfering with the canopy center bulkhead, which is the real overall factor for the seat back angle. The RV-4 is a fairly upright seating position, so moving the hinge at the seat back bottom can make that worse if you move it very far. Plan on thin but firm seat cushions, and get your rudder pedal travel to hit stops with pedals nearly touching the firewall (watch brake throws too). Since I am nearly always with a back seater (wife who likes to fly!), I needed the rear stick functional, and have it adjusted so full forward is 1/8" from my seat back. She is 5'11" and I installed the rear seat footwells (a must), and we are comfortable on 2 plus hour trips non-stop. You will love the -4!
__________________
Bill E.
RV-4/N76WE
41 Aeronca 65TC Defender
8A7 / Advance NC
Reply With Quote
  #5  
Old 06-18-2018, 05:49 AM
RyanB RyanB is offline
 
Join Date: Sep 2017
Location: South Africa
Posts: 36
Default

Thank you for the detailed response Bill, I really appreciate all the info. Any idea how far you moved back F405/406?
Reply With Quote
  #6  
Old 06-18-2018, 07:02 AM
fixnflyguy fixnflyguy is offline
 
Join Date: Jan 2006
Location: Winston-Salem, N.C.
Posts: 917
Default F405/406 adjustment

Its been 15 years since I built mine, but I kept the floor level positions as per plans and shifted the top slightly aft. There is a lot of stuff going on at the upper longeron /rollbar attach point to make sure fits well, such as the roll bar bolts, ect. . Can't say exactly how far I moved them, but its probably no more than 1-1.5".
__________________
Bill E.
RV-4/N76WE
41 Aeronca 65TC Defender
8A7 / Advance NC
Reply With Quote
  #7  
Old 06-18-2018, 03:02 PM
Michael Henning Michael Henning is offline
 
Join Date: Jun 2011
Location: Nashua, NH
Posts: 483
Default

And like Bill said, you WILL love the -4. It is a fabulous airplane.
__________________
Mike
RV-4 #2750
N654ML
IO-360
WW150C Prop
1018 lbs
Flying
Reply With Quote
  #8  
Old 06-18-2018, 03:36 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,017
Default

Does Van's endorse moving the roll bar without moving the bulkheads? Sounds like something that isn't a problem until it is.

FWIW, I followed the lead of a friend, and simply moved the top of the seat back from the front of the cross bar to the back, using a couple of hand made 'adel clamp' type straps around the crossbar and screwed to the top of the seat back. I notched the tops of the vertical angles to nest around the crossbar. It made a huge difference in the comfort of the seating position. I'm not that tall, though (~5'9"). I really don't know if this mod would have you hitting your head against the roll bar.

You might want to find a -4 to sit in, and see if just reclining the seat a couple more inches would accomplish what you need.

Charlie
Reply With Quote
  #9  
Old 06-18-2018, 05:35 PM
Michael Henning Michael Henning is offline
 
Join Date: Jun 2011
Location: Nashua, NH
Posts: 483
Default

I did the mid as exactly per the plans, and no bulkheads needed to be moved. That area is extremely strong.
__________________
Mike
RV-4 #2750
N654ML
IO-360
WW150C Prop
1018 lbs
Flying
Reply With Quote
  #10  
Old 06-19-2018, 03:39 AM
RyanB RyanB is offline
 
Join Date: Sep 2017
Location: South Africa
Posts: 36
Default Tall

Great responses, thanks gents. I am 6í2 and have sat in a standard 4 and one that has been modified. The mod makes a huge difference.

Sadly I donít have access to the modified one for reference
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 11:05 PM.


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.