Elevator Travel Question

Fellow RV fliers: I started my conditional inspection today and while going over the airplane, my DAR hangar mate questioned me on the upper elevator travel limit on my RV-4 (I did not build this airplane, but I have been flying it for a couple of years). I hadn't seen it before, but the after limit of travel for up elevator is when the elevator horn hits a portion of the aft structure.

The measured up and down angular movement of the elevator appears to be correct but there is no up stop, or at least there is not one before the elevator horn hits the back edge of the opening it sits in. The edge it hits has made a chafing mark (groove) across the back of the elevator horn. I can't find anything on this in the build book I got with the airplane.

Can someone who is building or has built, an RV-4, and who remembers this part of the build help me out here? Am I missing a stop, is the groove immaterial, or should I put some sort of chafing protection in place? Any assistance would be appreciated. This looks to be a safety of flight item to me, but perhaps is in fact "as designed". Thanks!

Regards,

Lee...

My RV-4 Manual, circa 1991, lists elevator travel as such:

Design Limits 30 up, 25 down
Minimum acceptable limits 25 up, 20 down

I will have to unbury my RV-4 plans to see what the aft stop looks like again.

The up stop on my RV-6 plans shows that the stop is made from 1 inch by 1 1/4 inch aluminum angle and is mounted across the fuselage at the rear and on top of the flat piece (aft deck-I believe?) under the horizontal stab.

I think from your description that your airplane is built per plans.

I was at that stage of building only a couple weeks ago. The up elevator stop is supposed to be a piece of 1/8? thick aluminum angle (3/4? x 3/4?). It is mounted just below the opening that you describe. It should be riveted to the rear bulkhead (F-412). If you have a flying RV4, it will require removing the vertical stabilizer to rivet on. It is described in the builder?s manual on page 8-11, under Control Stops. Only the position is shown on Drawing 30, not the stop itself. The same goes for the down elevator stop. The travel limits are best described in the ?Final Inspection and Flight Test? chapter on page 15-2. The elevator up travel limits are 30/25. The down limits are 25/20. If you want to send an email address, I will try to take a picture. It may be hard to see the stop though.

Cameron Smith
RV4 #68

Just the information I was looking for guys, thanks a lot. Mine is hitting a stop, but I suspect not quite the correct stop. I really appreciate your time and trouble. A photo would be very much appreciated.

Regards,

Lee...

I'll be glad to send a picture, but send me your email address by private message. I know it takes a few extra steps to insert a picture in these post ( I haven't done it beftoe). I also don't think that I can attach a picture to a private message. If I get an email address, I'll take a picture tomorrow night and email it.

Cameron Smith
RV4 #68

When I was building my 4 I found that the correct amount of up travel occurred when the elevator control horn contacted the aft-most bulkhead. I emailed Vans about it and they said that the rear bulkhead would be as good a stop as anything else.