Tail construction

[jrbirdman47]

Once again, work interferes with important stuff like building an XL....... But on the plus side, it does give me too much time to think about construction techniques and come up with more questions for y'all!

I've looked over the past postings and even perused YouTube to get ideas on how to actually put the tail together. Not finding much.

I'll probably be doing it next week, and it seems that it will take 5 out of the 4 hands available to hold everything in place, drill holes, pull rivets, devise the precise choice and sequence of curse words, etc.

If you've "seen the elephant":

*Did you jig the components in place on the bench somehow to maintain proper component relationships during all the above mentioned activity?

*How did you bend the gussets? Were they pre-bent to shape or riveted flat to one side and then rolled to the other side and riveted? If pre-bent, how did you do it and make a nice, round bend?

*Did you drill/ rivet through the rib "extension" and tube together? If so, did you overlap the rib extensions where two of them joined at an angle, making 3 layers, (two ribs and the tubing), or did you put them side by side? And if side by side, did you then use 2 rivets, top and bottom?

*If all this overlapping was done, wasn't the gusset all kinked to rivet the different thicknesses along the tubing?

*Did you paint the rivets as corrosion protection before installation per plans? If so, with what?

*I could come up with more, but my head hurts now........

Any insights are greatly appreciated before I begin. If you have pics or videos, that would be a bonus!

Thanks!  Rick

[Kamcoman77]

Attached photo shows how I located members on build table. I hand bent the gussets over a tube a couple of sizes smaller than the tube they go on. I drilled the gussets and ribs together on one side of part. I clecoed as I drilled, then turned the part over and placed on 2x4 blocks to hold it clear of the build table. I drilled the second side gussets and ribs and clecoed as I drilled. I installed a few stainless steel rivets on one side, turned it over and installed all the rivets. Turned it back over and installed the remaining rivets. My rivets are 100% stainless so I did not use any coating, paint, or sealer when installing. On overlapping rib ends. All were coped to fit tubing and did not overlap each other.

[jrbirdman47]

Thanks for the pics and explanation. As best I can tell, your ribs ends, top and bottom surface did not overlap the tube. In other words, there was no rivet that went through the rib "extension" and tube, so that all rivets in the tube only go through the gussets, which allows it to lay flat along it's length in contact with the tube.
The ribs only have rivets along that portion opposite the tube from the coped area. 
I also have all stainless rivets on hand, so that'll save painting them.
I like the idea of using Clecos before final rivet pulling is done.

Thanks much! It helps to see what has been done so I'll know what lies ahead.

[Kamcoman77]

You are correct that the ribs do not overlap the tubes enough to hold a rivet. The ribs are coped to the tubes. I used Marson SSB4-1S rivets (shortest ones available). I did overlap the tubes at the outer and upper ends of the tailfeathers and put slightly longer rivets (SSB4-2S) through the gussets and tubes at these locations.

[jrbirdman47]

Thanks! Those are the same rivets I am using as well. Did you have a problem with the gusset kinking where the ribs did overlap the tube, or is there enough flexibility in it so it wasn't a problem?

[Kamcoman77]

My ribs did not overlap the tubing, only coped to fit. If rib end projected over tubing I cut it off so there was no overlap. I wanted smooth transitions from ribs to tubing so gussets would not bow up or kink. I made a small aluminum flanging tool to slightly fold down the exposed edges of each gusset to give the gusset additional rigidity. My ribs were made longer than 1/4" on the sides. I used the flanging tool to slightly fold about 1/4" of each rib edge downward, also to increase rigidity & to prevent sharp edges from contacting fabric covering.

[jrbirdman47]

Thanks! I had planned to bend the gusset edges down as well and I bet I have the same tool as you used. Also hope to be able to bend the rib edges down  at least 45 degrees as you did for added rigidity so I made them a bit wider as well. Thanks so much!

[jrbirdman47]

I'm really enjoying the metal work, mostly because it's not wood work. But I got a lot done in the last two days, and only have to make 3 more elevators and the tail group will be behind me. Ahem.......

Anyway, once I got over the intimidation and dove in, we got the things jigged and riveted and it wasn't as hard as I thought. A couple of small mistakes but nothing we couldn't re-do. I'm very impressed with how sturdy these tail feathers are!

I really appreciate the advice and answers above!

[jrbirdman47]

Pic is of the outboard end of the elevator. I was pretty intimidated by the 3/4" to 3/8" junction. Taking it slow and blocking things up to maintain center on the 3/4" tube and "massaging" the gusset into place under pressure , then riveting it before anything could move actually worked. Then flipped it over and repeated. Made for a tight, sturdy connection and no twist in the final product.

[Kamcoman77]

Very nice work!

[Chuck in Indiana]

Yes, that's a nice piece of work there..

[Kamcoman77]

Don't forget the compression bushings for your bracing cables in your horizontal stab. They may be there, but they don't show in your photo. I used short pieces of 3/16" ID 6061-T6 and JB-Welded them in place.

[jrbirdman47]

I plan to install the bushings tomorrow. (I had planned to do the JB Weld thing as well. Nice to have my thinking validated!) I was going to install the bushings during the build, thinking access would be difficult when finished, but we tried one and it looks like it'll be fairly easy to install now that we're finished.

Took about 7 days from bending tubing through first cut to last rivet. Now it's time to start melting steel! (well, after I clean up 685 stainless rivet tails and what seems like pounds of aluminum chips, shavings and such)

[Poorman2]

JRBirdman, did you put your hindges on before riveting it all together or are you using a different hindge setup?

[jrbirdman47]

We're using a different set up. It will be riveted to the 3/4 tube. Hoping to save a bit of weight vs. the steel slide on pieces. Still in the design phase.

I've seen a similar hinge somewhere on here; it looked like the steel ones in the plans with the rear half cut off and then riveted to the tube. We're thinking of something similar.