Elevator Pushrod Question

After installing the Elevator Pushrod from the control yoke to the Elevator Bellcrank. The hole that it passes through directly below the seats, I noticed very little space between the bottom of this hole and the pushrod like about 1/8" when the controls are at the neutral position. When you move the control stick quickly it hits this bulkhead/spar opening. Anyone else seen this issue? Looks like I will have to fab a small delrin pad for it to bump on.

pushrod

If I understand what you are describing correctly, it is not uncommon. you then have to enlarge the holes so you can get full control movement. Jack

I checked my 7A QB. The clearance is about 1/8", but the pushrod has an Upward Motion when you push or pull the stick-therefore increasing the clearance. You might rotate the pushrod to see if you have a "Sweet Spot", mine had a slight "out of round" motion (put the high side up). It may also make a difference if you have the HS & Elevators hooked up too. Hope I've helped.

Derrell

I found a similar situation on mine, so I enlarged the hole and made sure the vertical position of the control column was as good as possible. This seems like a very important issue to me, since g loads can cause EVERYTHING to flex a bit. Bottom line: make sure that nothing can possibly bind!

OK thanks guys, I'll see what needs to be done. I hope I can get at least 1/4" of clearance.

tech support

RV_7A said:

OK thanks guys, I'll see what needs to be done. I hope I can get at least 1/4" of clearance.

Click to expand...

Upon re-reading your original post, I'm not sure that you have the same clearance problem that I had. Before you do much modification, I'd suggest a 2 minute call to Vans tech support. Give them the dwg. # and they can "see" what you are describing. They have always been helpful to me. And it always gives me that added since of security that I'm not doing something I shouldn't.

Thanks Jack, After talking to other builders, it seems is the norm on 7's and 9's. Most are just removing 1/4" of metal from below the rod. Here is a pic of what I am talking about looking towards the front from behind the flap motor. With the controls at neutral position.

This may be a little too late in the discussion, but I'm about to put mine in (might make some more clearance per your suggestions). But what's the best way to get the thing in there?

Thanks much in advance

I think Ken Scott had a step-by-step on this very question in the last RVAtor. I'll dig around for it.

Well here's what we have found. First of all Vans tells you to cut the tube 45 15/16" . If you cut it this long and install the threaded rod-ends it is barely long enough to get a few threads in the rod ends and for everything to line up in the neutral position. I actually cut mine 1/2" longer and it allows you to screw the rod-ends on the threads a bit more. (remember Mr. Van like to keep his planes light) The rod can be installed from the rear (without the rod-ends installed) and through the hole like in the picture above and then come back through the hole in the rear where the bellcrank is mounted. You can then screw the rod into the front rod-end which you should already have installed in the control column. Then just screw the rear-rod end on by hand, check length and install the rear bolt. Remember, if you cut it to the length shown on the plans, and the end were to come loose from the jam nuts the rod could come unscrewed and fall off. NOT GOOD!

Jeff

Ahh, here it is. It's actually from 2003. Just goes to show you that time stands still when building an RV.

First, remove the rodend bearings before installing the pushrod. A shorter rod is easier to install. Rod still too long? Don't be afraid to flex it slightly... just aas long as you don't bend it permanently. Still won't fit? Use a unibit to make a rod-sized hole in the F707-907 bulkhead, roughly in line with the pushrod. Slid the push-rod aft, through the hole, to gain clearance, then forward into the cabin.

Now that you have it in position, it's time to bolt the pushrod and washers to the control column as shown on DWG 38. If you have already installed the column and manual aileron trim mechanisms permanently, there won't be much access. It can be difficult and frustrating to get those washers in from the top. The easier way to do it would be to remove the control column, install the washers, rodend bearing and bolt out on the bench where the cussing can so some good, then thread the pushrod into the bearing when the column is re-installed. It's a lot easier to tighten the jam.

This technique works even better with the aileron push-rods (which have the smaller, nastier 5702-75-60 washers) because it permits accurate "clocking" of the bearings on each end.

Thanks Bob! I'm sure that will help. Unfortunately, I wasn't even thinking about RVs in 2003.

Again, thanks for retyping all that good info.

Scott

Check out 24 Years of the RVator. Not sure if this particular info was in there, but it does have some useful tibits.

Dave