Rudder stop frustration

Fitting the empennage to my RV-7A fuselage has been going very well until today. I fitted the new-style rudder, and installed the rudder stops that I carefully fabricated. The rudder bearings were all set to the recommended starting point. Instead of 1-1/8" of clearance between the rudder and elevators, it was more like 1/8". And the rudder swung much further than 35 degrees.

I searched through the old Yahoo Groups RV-7 archives. There was a thread about this a while back. It seems that some builders have no problem and others do. Is there any new info on this problem?

I tried cranking in the bottom bearing. It's now in quite a bit, 29/32", from the recommended starting point, 1-1/16". The gap is now better, but still only 1/2". There's not much more I crank in the bottom bearing. There are only a few more threads exposed.

Here's the current state:








Should I keep cranking in the bearings, or just make new rudder stops?

Thanks,
Dave

I can't quite tell if your stop has the 13/32" flat that projects out from the fuselage. Anyway, here are two shots of mine. They worked without need of adjustment. It is strange why some just don't work the first time and require remake.

Hope this helps,

Roberta

Rudder Function/Stops

Rig the rudder for proper function and make new stops. They had to be made for my small rudder and vertical stab RV-6A (before aerodynamic balance horn) and it is certainly a simple task. I tried to attach a JPG file showing them but there is some incompatibility that I am not going to waste time trying to fix. The two things I worked on were minimizing the gap between the rudder and vertical stabilizer and avoiding contact with the vertical stab skin extensions at the specified full rudder deflection (with a "little" extra space for paint). The rudder stops didn't even enter my mind as the are just static parts that are intended to do nothing but provide correct performance limits that compensate for all of the variables in building the airplane. Then I made the rudder stops to limit the rotation to the specified maximum angles. The line of the initial cut at the rear of the horizontal surface of the stop should angle back from the trailing edge of the fuselage skin to a point where the stop contact surface can be cut to be butted against the rudder control horn when it is at the maximum allowed deflection angle. this projects the stop angle back behind the end of the fuselage where it can perform its function. I can't tell for sure from your photograph but it looks like the rear end of your stop surface goes directly to the edge of the fuselage in one straight line instead of having one line for the contact surface at the proper location in space and another line cutting back to the trailing edge of the fuselage skin for clearance and removal of unnecessary weight. In other words it looks like the stop was made wrong. In Roberta's photo you can clearly see the two surfaces. You need to make new stops I believe.

I edited my original post to state that this is a new style rudder on an RV-7A. Same as Roberta, I believe.

I also took some additional photos that show my rudder stop and put them in the top post. To me they look identical to Roberta's set up. I also re-confirmed all of the measurements on the stop. It all matches the plans.

I also found these pics on Walter's site:





Of course in the amount of time I've taken to fret about this, I could have just made new stops.

Should have just gotten one of these...

http://www.aerogenic.com/RUDDERSTOP/RUDDERSTOP.htm

That thing looks cool, but doesn't $40 seem a bit much for a couple bucks worth of plastic?

Steve Zicree

Very clever idea

I like this idea. I used delrin rod for my aileron stops, so something like this
would have real symmetry on my aircraft!

http://www.rv8.ch/article.php?story=20040924215600851

Not when most plastic supply places sell you a minimum of a $50 that you will never use. Not to mention cutting it out precisely.

szicree said:

That thing looks cool, but doesn't $40 seem a bit much for a couple bucks worth of plastic?

Steve Zicree

Click to expand...

Variations on a rudder stop

I agree, save the $40, but there are ways to make the kit materials look a little better. Thats why you bought that fancy bandsaw right!

-Mickey, thats a great idea on the ailerons! I sure am glad I'm building an experimental aren't you?

Jeff

RV_7A said:

Should have just gotten one of these...

http://www.aerogenic.com/RUDDERSTOP/RUDDERSTOP.htm

Click to expand...

Cool idea. Have you installed the VS on the fuselage yet? Two of the VS-fuse attachment bolts go right through that lower hinge bracket. Looks like they might interfere.

Yes I have installed the HS, VS, Elevator and Rudder and no there is no interference. Works beautifully...

Jeff