Initial Rudder Assembly. Should I install tips?

Bullseye · #1 03-02-2010, 07:35 AM

Good morning, everyone.

After getting the rudder assembled and matchdrilled on Sunday, I got everything taken apart last night, and then started questioning when to install the fiberglass tips. I am planning on attaching most, if not all, of the fiberglass fairings with screws and nutplates, which will require dimpling/countersinking of the components.

Here?s the catch. Take the rudder bottom tip attach strips. If I disassemble, deburr, scuff, clean, prime, and rivet them back to the skin/bottom rib, I?ll be drilling through primed parts when I go to install the bottom fairing (and nutplates) later. Do people re-prime these parts (mainly the holes) after they are riveted to the already riveted rudder?

I?m thinking that maybe I should re-assemble everything, layout the spacing for the fastener attach points now, drill, and then go ahead and do the normal disassemble, debur, scuff, clean, prime, and rivet dance. I can get the holes drilled in the rudder bottom tip and attach strips now, isntead of after I prime.

What have other people done here?

Mel · #2 03-02-2010, 07:58 AM

Do not fit or drill the rudder bottom until you have it on the airplane. You may have to "raise" the lower fiberglass tip to clear the tailspring.

Bullseye · #3 03-02-2010, 08:11 AM

Ahh, now I see.

I read that step in the directions, and thought it would be a modification of the bottom forward part of the tip (and therefore, because I was attaching it with screws, would be no problem to attach now).

I now see that the whole thing will need to be, how do you say, re-inclined, to clear the spring.

I shall wait.

But that brings me back to to the re-priming question. What do builders to when they have to drill into a primed part. Deburr, (dimple, countersink if necessary) and spot prime?

Rick6a · #4 03-02-2010, 08:11 AM

Quote:

Originally Posted by N999ZA

.....What have other people done here?

Using screws and nutplates to make all the components removable, I completed all fiberglass work as I went. Later during final assembly, I did not experience any conflicting problems with fit including the tailspring.

RV7ator · #5 03-02-2010, 08:47 AM

Rivets swell up to fill the hole and thus exclude air/moisture that cause corrosion. It's exactly the same concept as crimp terminations. Priming is not necessary. If you don't buy that, what are you going to do about those thousands of unprimed/unpainted rivets?

Rick, I've got a question for you as I've considered making the rudder bottom cap removable on my 4th project. Can you remove/install the cap without the tail spring and fuse skins preventing extraction? It's well captured by these features, particularly since it would have to drop about 1 1/2 inches to clear the rudder yoke, and the tail spring clearly is in the way.

John Siebold

noelf · #6 03-02-2010, 09:07 AM

...I see that you are working towards a 7 and not the 7A. On the -A's there is a great probability that the rudder bottom fiberglass tip will hit the Vertical Stab in the area where the lower attach bolts are located. This becomes a chore to deal with if the bottom tip is riveted in place.

As Mel has suggested, deal with this item once the vertical stab is on the airframe and you can see what needs to be "adjusted" to fit.

Rick6a · #7 03-02-2010, 09:23 AM

Quote:

Originally Posted by RV7ator

.......Can you remove/install the cap without the tail spring and fuse skins preventing extraction? It's well captured by these features, particularly since it would have to drop about 1 1/2 inches to clear the rudder yoke, and the tail spring clearly is in the way.....

John,

To answer your question, I really don't know. I have not had to remove the rudder bottom since final assembly. Worst case, I would think partial disconnection of the rudder assembly from the vertical stab should make short work of removing the rudder bottom.

flion · #8 03-02-2010, 11:40 AM

Quote:

Originally Posted by N999ZA

But that brings me back to to the re-priming question. What do builders to when they have to drill into a primed part. Deburr, (dimple, countersink if necessary) and spot prime?

Depends. Your exposure is small, and so are the risks. Since you will be installing nutplates, the screw holes themselves will get scuffed free of primer as you install/uninstall the fairing but you would not expect to get a lot of corrosion from such little exposure. As pointed out above, the rivets tend to fill the hole so no exposure to oxygen there (either airborne or waterborne). However, the truly anal (and I don't mean that in a bad way) will spot prime. I've heard of people using a Q-tip or toothpick to get primer into a drilled hole. Then there's the whole primer wars battlefield #1, do you need to prime at all? My -6 was completely primed (I expected to return to San Jose or vicinity when I started building) but my RV-10 will not have any alclad primed, so you can see that I'm impartial (yeah, right; well, at least I'm willing to weigh the pros and cons) when it comes to priming. I would say you hurt nothing by going either way; it's whatever makes you comfortable.

Mel · #9 03-02-2010, 02:32 PM

I guess my big question is why do you feel that you need to make the rudder bottom removable?
I've had mine on for over 17 years and have never seen a need to remove it.

L.Adamson · #10 03-02-2010, 02:54 PM

Quote:

Originally Posted by Mel

I guess my big question is why do you feel that you need to make the rudder bottom removable?
I've had mine on for over 17 years and have never seen a need to remove it.

Mine is permanent too. The tail light is removeable by pulling the screws out. The nuts are fiberglassed in place. There is some slack in the light wire, which allows it to be unplugged.

L.Adamson -- RV6A