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RV-4 rudder pedals - deliberate misalignment??

chris mitchell

Well Known Member
Just completing the firewall and I see that the inner and outer pivots for the pedals are on different axes - ie, misaligned by 9/16", with teh outer pivot point further forward. I have looked hard, studied the arrangement, thought about it, and cannot see what benefit there is - though there is plenty of friction and will be extra wear in time. I note that Tom Martin added an extra bracket to the inboard pivot - which I think is just visible in one of Ax-O's photos. I am inclined to make this modification, but also to modify the outer pivot so that the outer one is aligned with the inner one - seems a much more satisfactory solution to me unless someone can see a problem or tell what what the advantage is of the arrangement per plans??

Thanks

Chris
 
It has to be for tunnel geometry

When I built mine, I had same thought, but Van is a smart guy! The geometry of the tunnel between your legs mandates the offset hinge points,as it gets wider going AFT and everything just fits...build it per plans. It is un-noticable when operating them.
 
Hmm take your point

about the tunnel - and of course we can't move the tunnel because of the mounting points for the engine mount frame - but that's definitely a bodge!! The holes I lovingly drilled undersize and reamed on a drill press to ensure they were round, normal to the surface of the bracket, should in fact either be sloppy - likely they will get sloppy pretty quickly - or on the slant. Eeek. Alternatively bend the brackets some. Or just do it like the plans say and accept that it works just fine and has done for a couple of decades!

Build on!

Chris
 
I also thought that was weird and did not like the design. I figure it had to do with the tunnel versus the pedal swing. I decided to add the extra bracket and keep the rest of the design per Vans. I am sure there is a reason for it.

IMG_1717.JPG


IMG_1719.JPG


IMG_1720.JPG
 
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Another variation

I don't have pics, but I bought some really long AN bolts that pass all the way from the inner bracket to the outer bracket to prevent binding, racking and uneven wear of the bolts. Don't know if it was necessary, but it works great.

I thought this part of the RV4 design was less elegant than the rest of the design. ;)



M
 
RV4 rudder pedals

The mounting is necessary to make the rudder pedals swing parallel to the center tunnel. I cut the pedal frames and put a twist in them; then welded them back together. This makes the pedals set parallel to each other but swing parallel to the tunnel. Jim Winings 317/718-3415 (Another fast back 4)
 
I'm installing the rudder pedals on my new project. I had a quick question about the alignment? They pivet very nicely without any binding but looking down on them they are not square with the fuselage or each other. From what I've read, this is by design. Is this correct?
 
YEP..they are supposed to be

They will travel parallel to the tunnel more so than the fuselage side skin, thus keeping them from hitting the tunnel, as they would if they come straight FOR/AFT.
 
..........but looking down on them they are not square with the fuselage or each other. From what I've read, this is by design. Is this correct?

that is correct. Don't forget the service bulletin for the pedals while you are working on this.
 
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