Rudder Gap Distance ??

[southwind32]

The plans call for 1 1/2 inches at the top and 2 5/16 inches at the bottom between the trailing edge of the vertical stabilizer and leading edge of the rudder, the plans I have show no fiberglass fairings in the drawing. I'm installing the fiberglass fairings, taking into consideration for the thickness of the fiberglass, I adjusted the turn barrels to the proper length. The trouble is, I ended up with no gab, in fact, I'm about a 1/3 of a hole from getting a bolt in the bottom hinge point and the top is up tight.
The fairing on the stab is up tight against the tail post, which took some adjusting etc. and the rudder fairing is equal distance from the vertical tubing on the rudder. Both fiberglass pieces are straight, and fit nicely on the bench, but using the plans measurements the ruder doesn't line up.
What I'm considering doing is placing temporary spacers at the top and bottom of the tail post fairing at the vertical center line near where the turn barrels screw in, run the turn barrels on and install the rudder. Adjusting the turn barrels, till the rudder leading edge is just touching the spacers. This will take a little trial and error. Not sure of the spacing between the two pieces, hopefully someone can give me an idea what that space might be. I'm thinking 1/4 maybe 3/8 of an inch, whatever will give satisfactory space that will allow no touching between the two surfaces while moving the rudder from stop to stop, I'll also take into consideration the thickness of the covering material,
I'm interested in hearing how others did theirs? Thanks
Brian

[David47]

Brian, I've just recently fitted my rudder up after installing both the vertical stab FG fairing and rudder FG leading edge. Like you I set the distances according to the manual and ended up with no gap as well. I backed out the rod ends until I achieved about 3/16" gap - backed each of them out around 1/4" more than the manual figures. Took a bit of tooing ad froing but works well now. Distances in the manual will only be approximate because, for instance, my vertical stab fairing varied in thickness by a good 1/16" top to bottom and when I installed it, I also installed it slightly off centre by about 1/16". In my case these dimensional variations didn't help. So I think your method sounds ok, but just make sure you have enough thread engagement of the rod end. I checked mine and I still have around 50%, including stop nut. PS: In the photos below the gap looks bigger than it actually is.

[efwd]

Funny, my holes look exactly like yours David.

[southwind32]

Brian, I've just recently fitted my rudder up after installing both the vertical stab FG fairing and rudder FG leading edge. Like you I set the distances according to the manual and ended up with no gap as well. I backed out the rod ends until I achieved about 3/16" gap - backed each of them out around 1/4" more than the manual figures. Took a bit of tooing ad froing but works well now. Distances in the manual will only be approximate because, for instance, my vertical stab fairing varied in thickness by a good 1/16" top to bottom and when I installed it, I also installed it slightly off centre by about 1/16". In my case these dimensional variations didn't help. So I think your method sounds ok, but just make sure you have enough thread engagement of the rod end. I checked mine and I still have around 50%, including stop nut. PS: In the photos below the gap looks bigger than it actually is.

Got mine all adjusted, and I have at least 50% of the turn barrel threads inserted. I wonder what the safe limit is on how much of the threads need to be in? I literally spent hours using the measurements in the instructions, the taking into effect the differences in the thickness of the FB fairings, and still was to tight. I ended up adjust them like you, and it will be fine. Actually, the final adjustment will be once everything is covered.

[jiott]

Don't get too wound up about the gap yet. Wait until everything is covered and painted. Also, don't grind your rudder travel stops yet until final gap is set after cover and paint; if you do it now and then have to back it out a little more after cover and paint, the travel will be too much and you will have to come up with a way to add more material to the travel stops or some other method.

[southwind32]

Don't get too wound up about the gap yet. Wait until everything is covered and painted. Also, don't grind your rudder travel stops yet until final gap is set after cover and paint; if you do it now and then have to back it out a little more after cover and paint, the travel will be too much and you will have to come up with a way to add more material to the travel stops or some other method.

Good Advice, Thanks Jim, how's your engine?

[efwd]

Crap.. thanks Jim. Think I'll be adding a wedge.
Probably Kitfox should add to the manual so guys like me don't screw this up. Or, what's the harm in having a few more degrees travel? Suppose my pedals will bottom out?
Eddie

[David47]

Funny, my holes look exactly like yours David.

Great minds Eddie !

[David47]

Don't get too wound up about the gap yet. Wait until everything is covered and painted. Also, don't grind your rudder travel stops yet until final gap is set after cover and paint; if you do it now and then have to back it out a little more after cover and paint, the travel will be too much and you will have to come up with a way to add more material to the travel stops or some other method.

That's very true about the gap, and I've read this advice elsewhere on the forum as well.

With respect to grinding the rudder stops at this stage, you can fit adjustable stops without too much effort if you take off too much. John Pitkin has a simple but effective adjustable stop detailed somewhere else on this forum. That's what I've done with mine. Quite straight forward.

Jim, hope you sorted the leak in the radiator. Bad luck about missing the flyin.

[jiott]

Yep, I sure was disappointed missing the fly-in, but very glad it happened only 15 min. from home. Could have been much worse. I am now waiting for back ordered radiator. As far as the engine goes, according to Rotax with cht of 350F for less than 30 minutes, I need to thoroughly inspect the cooling system and check the head bolts for looseness. Sounds like I should be OK.

Regarding rudder travel stops, no problem with more than the 25 degrees specified as long as the rudder does not hit the elevator. Also your pedals might hit the firewall at the most forward adjustment position.