elevator pushrod problem

[RV7A Flyer]

I have a -7, not a -6, so I don't know the details of construction on a -6 and how they differ, but...

Are the F-633 control column mounts positioned correctly (impossible to do on a -7 due to pre-drilled locations, but maybe not on a -6??? I don't know if they're pre-drilled or not).

Just a thought, and it may not even be possible to mount them too hight, don't know. Just thinking out loud.

[WingsOnWheels]

Originally Posted by az_gila

Colin,

You used 5 degrees for the stick angle, but as I read it, the easier method is to make the drive horn (Detail A in the picture) vertical when the system is in neutral position.

This is what the plans seem to show.



If you change the stick neutral angle, does it help? My scan is different from the green neutral lines in your CAD drawing.

Ill recheck my stick angles in the cad drawing, maybe i messed something up there.

In my actual installation, i have played with all sorts of neutral points. The closest in have to clear is with the sticks vertical at neutral. But that still leaves me with a bit of a problem at full down elevator.

The only place i can fimd room for error it at the f-633 vertical position. I mounted mine withe with mounting hole 1/2" from the top edge, but on of the pictures i saw from someone with no issue, it looks like theirs was closer to 3/8". That may be all it takes to make the difference.

[WingsOnWheels]

Originally Posted by Mel

Is it possible that your seat ribs are from an RV-7?
The seat pans were lowered for the -7 and -9 to increase headroom.

I dont think so, but ill check my ribs to be sure. I think there are other differences as well, like the shape of the lightening/aileron cutout. Mine has the traditionl round cutouts.

[WingsOnWheels]

Originally Posted by RV7A Flyer

I have a -7, not a -6, so I don't know the details of construction on a -6 and how they differ, but...

Are the F-633 control column mounts positioned correctly (impossible to do on a -7 due to pre-drilled locations, but maybe not on a -6??? I don't know if they're pre-drilled or not).

Just a thought, and it may not even be possible to mount them too hight, don't know. Just thinking out loud.

None of those parts are prepunched on the -6, but the position called out one the plans is specified as approximate. I think moving these lowers is my best bet for a fix.

[Ralph Inkster]

Originally Posted by WingsOnWheels

None of those parts are prepunched on the -6, but the position called out one the plans is specified as approximate. I think moving these lowers is my best bet for a fix.

LOTS of work (IMHO). Again, take a look at a 7 or 9 model & see how the factory delt with this clearance issue in later designs. Copy the center tunnel cover used in these models & trim the seat pan accordingly. The structure is virtually the same these models as in your 6.

[WingsOnWheels]

Originally Posted by Ralph Inkster

LOTS of work (IMHO). Again, take a look at a 7 or 9 model & see how the factory delt with this clearance issue in later designs. Copy the center tunnel cover used in these models & trim the seat pan accordingly. The structure is virtually the same these models as in your 6.

Putting in new F-633 l&r shouldn't be a big deal. Four bolts all together. I did check last night and i can remove the section of the tunnel cover under the flap motor assembly and it will do the job, but i would rather address the root cause if possible.

[WingsOnWheels]

I did another quick check with my CAD model. If I move the F633 down just a little bit, it solves all my interference problems. So that is my plan. I'm going to double-check a few measurements first just to be sure. If that all checks out, I'll spend the $70 for new parts and be done with it.

Thanks everyone for your help. Having the pictures from other builders definitely helped clear things up. I'll report back once I get the new parts installed.

[JanRV6UK]

I had a look at my two F633 - I have the pivot point for the stick assembly - 1.062" down from the spar top bolts .. How does that compare with your cad model layout ?

[az_gila]

Originally Posted by JanRV6UK

I had a look at my two F633 - I have the pivot point for the stick assembly - 1.062" down from the spar top bolts .. How does that compare with your cad model layout ?

Interesting, the plans show 1.25 inches down from that bolt hole - but does use the term approx.

IIRC the angle came cut to length from Vans with the stick pivot bearing already installed so the builder had little control over the 1 3/4 dimension shown in the plans.

I'll measure mine...

UPDATE

Mine measured 1.28 pivot to upper bolt hole.

[JanRV6UK]

I had a another look and re measured ... I have 1.107 to the bolt hole centre ... and then I have 0.611 from the bolt centre to the top the bracket ....