How much access do I need to fit the tail spring mount?

I am currently working on the aft fuselage and my tailwheel assembly is still on a backorder.

Since I don't have WD-409 Tail Spring Mount part, I cannot fit it to the F-711 / F-712 bulkheads and the bottom aft skin F-779. The plans want you to assemble F-711 / F-712 / F-779 / WD-409 together first, then rivet it to the rest of the aft fuselage as an assembly.

I would like to rivet as much as possible, but without making fitting the WD-409 in the future to be a complete pain. Somewhat more painful is acceptable, I guess. I am considering riveting everything in front of the F-711 (including the F-711 itself) and only leaving the very aft of the side skins loose, so I can spread them apart and insert F-712. Drill the socket hole to 3/4", cut the bottom aft skin using the template (or, maybe, a bit less, just in case?).

Once I get WD-409, I will drill it to the F-711 from the front, then attach using the temporary fasteners & drill from the F-712 side for the keeper rivets.

Do you see any issues with this plan? It seems like this is how Quick Build fuselage is done, right? Where everything except the F-712 is riveted together?

Same place

I’m just about the same place as you. On the previous RV-7 I built the rear fuselage was riveted together when I decided to build a taildragger instead of an A model. I removed all the rivets for F-711 & 712 so I could get them out and deal with the WD-409 mount.

I’m also waiting on the tail wheel mount that is on back order. I plan on placing a cleco in every hole involved in those bulkheads and continuing with riveting. To ensure a little easier fit process I plan on leaving clecos in the front of F-711 for a few rivets.

sahrens said:

I removed all the rivets for F-711 & 712 so I could get them out and deal with the WD-409 mount.

Click to expand...

Why did you need to get F-711 out? For convenience or is it impossible to fit WD-409 if F-711 is in place already?

Mistaken

I had to go back and read my build log. I did NOT take out 711, only 712. I guess my memory is going on me. Sorry about the confusion.

But in my current build I still am going to hold off riveting 711 until I get the tail wheel mount. Here is my old build log where I discuss installing the mount

http://mykitlog.com/users/display_log.php?user=sdahrens&project=248&category=5097&log=127076&row=167

Okay, so I thought I was smart when I bought WD-409 separately just to have something to mount to the fuselage.

Up until the moment I realized that when you get a tailwheel assembly, it comes pre-drilled to the tail spring. Oh well. Now I have an all-fitted part that does not have a hole for the tail spring.

Since I wanted a different tailwheel anyway (and a taper pin modification?..), maybe, now I should buy an un-drilled spring, too (and get rid of the whole factory assembly once I get it...).

On the fitting part, being able to remove F-711 helps a lot. So I'm glad I did not rivet it permanently.

Anyone knows what's the difference between the factory-made tail spring and a Fly Boy Accessories one?

Drilling

I was tempted to install the WD-409 and wait for the tail wheel spring. But Vans advised that the tail spring is very difficult to drill due to hardness, waiting for the whole assembly would be better. If I had access to a mill I might be tempted to drill it anyway. So I’m still waiting for the whole mount.

I guess the biggest challenge would be accurately match drilling the WD-409 to the aftermarket tailwheel spring. It wouldn’t take much for misalignment and create tail wheel tracking issues. But I’m sure with the right equipment and jigs it could be done.