D

danny

Well Known Member
well, i just started building a -9 tail and am taking a little beak in order to pull a little hair and perhaps consume an adult beverage or 2.
my problem? i can't seem to build a proper trailing edge to save my life. the rudder was "better" (a relative term) when i hand bucked the rivets rather than back riveting them. the right elevator rivets were marginally acceptable but the TE is not very nice. i suspect i will use them for now but niether is what i'ld call "show" quality.
i haven't seen anybody write about this.....am i the only one having these problems? if not, how did you fix it or what did you do different from the plans or the film?
i WILL check in on the local EAA chapter. i think they are a great resource.
anyway
thanks
danny
 
Riveting the trailing edges...

When I riveted my trailing edges, I ended up using the next size longer rivet than called out in the plans. I did one series of rivets using the recommended size and ended up replacing them with the next longer size. The recommended rivets did not fill the countersink properly on the shop head side of the AEX wedge stock and bottom skins. As for the back-riveting, it worked out just fine. I did not use any tank sealing compound or any other epoxy, etc. I double counter-sinked the AEX wedge stock per the plans, dimpled both skins and made sure they were held down against the AEX wedge when I started to squeeze - - yes, squeeze just a little bit. I put the factory head of the rivet in the top side of the elevator (etc.) and made sure it was seated against the edge and squeezed just slightly to capture the skin on the shop head side of the rivet. After that, I layed the factory head side of the rivet and trailing edge down on the back-riveting plate and put the rivet gun to the shop head and it went well.

Sorry, I don't have any pictures of that from my web site to show you, but the process went well when I realized I could squeeze slightly, then finish the job with the rivet gun and mushroom head on the back-riveting plate. I just scanned my web pages from the wing construction days and find no closeup photos to show you from that process (sorry).

Jerry K. Thorne
RV-9A N2PZ 124.6 Hobbs hours
www.n2prise.org
 
Danny--

From you post I'm not sure if it's just the rivet finish that's bothering you or whether it's the straigtness of the t.e. when you are done, and I'm not sure whether you followed Van's instructions on the trailing edge or not...

What I did was following Van's instructions, perhaps with a modification.

1. Make sure your flat surface is FLAT.
2. Weigh down your rudder/elevator/aileron/flap (whatever) during all drilling and riveting.
3. Use proseal on the trailing edge.
4. Cleco the prosealed t.e. onto alum. or steel angle
5. To make sure the alum. angle is flat (not all is!), rout a groove--if you have a router--into the edge of the table the depth and width of the alum. angle so that everything lays flush on the table surface. [I even drill/cleco through the trailing edge through the angle and into the groove in the table]
6. Let cure 4-5 days.
7. Back rivet as Van's recommends.--I used a single 2" x 4 ft piece of steel that I bought at Lowes and then took to a machine shop to have "grained" (smoothed). It cost about $7 for the steel and $10 to have it grained--sure a heck of a lot better deal than anything to tool suppliers offer! That length allowed me to back rivet the entire trailing edge without ever having to reposition the rudder or elevators.

I know there are other ways to do this successfully. That said, I have done the rudder, both elevators, and both ailerons. I now have 5 perfectly straight warp free trailing edges that I'm very happy with. In one or two places the back rivet set created a smile from the angle you use to set the tail of the rivet, but all in all the quality I think is pretty good. After paint, a lof of what you think are ugly rivets/smiles will disappear.

I'll try to post a pic if I can find one.

Hang in there, and good luck.
 
Last edited:
Danny,

Don't worry about trashing parts. I have some extra skins laying around that I now use for other things.

Check out my aileron page, the construction method is the same. Once you use some angle aluminum to hold the trailing edge straight while the proseal dries you can squeeze the rivets per the plans. No back riveting, no rivet gun, no dents.

Good luck.
 
I used T-88 epoxy on a couple of surfaces and proseal on others, Both worked fine. Since the adhesive does nothing after the trailing edge is riveted I don't see that it matters. The T-88 is a whole lot more user freindly and you can set the rivets after 3 or 4 hours as opposed to several days. My own experience was my trailing edges came out much straighter when I used an adhesive first. Now that I've done all the control surfaces I probably could make a good part without the adhesive, but the whole reason for using it in the first place was to help an inexperienced builder make respectable parts.
I back riveted all my control surfaces except one that I used the pneumatic squeezer on. I liked the appearance of the parts that were back riveted much better.
Hang in there. It will get better. I scrapped an elevator skin while learning to use all the new tools I was not familiar with. I am a tool and die maker and have worked with my hands in metal all my working life but sheet metal is a different animal.
The best advice I could give is to find someone who has built an RV and ask for hands on help. Most would be glad to lend a hand.

Jim Wright RV-9A 90919 finishing wings Arkansas
 
ok, i'm ready to continue

thanks for the tips. i'v never heard of the T-88 but will check it out.
my first problem was with backriveting the rudder. worked better when i bucked them in normal fashion. the second was trying to follow the construction tape. he said ignore the manual but apparently i didn't follow the tape so well either. a big problem was not clecoeing the end ribs before drilling the angle and lower skin. it dominoed, one catastrophy into another, and i ended up drilling all the rivets out, oversizing the holes and putting the nas 4-4 rivets in. this is "better" but i'm calling for a "muligan" and will probably do it over when i need a break from the wings. everything else has gone as close to perfect as it can so this sudden blow out is pretty depressing.
anyway,,,,a little bit of moral support goes a long way and thanks for the advice guys.
later
danny
 
T-88

T-88 is the common epoxy used in wooden aircraft construction. Any two part epoxy will work just be sure to get one that has at least a one hour curing time. Any hobby shop will have something that will work.

Good Luck
Jim Wright RV-9A 90919
 
You must log in or register to reply here.