Tip: Cutting slot in tailcone skin for tailwheel mount

Just a word of suggestion for those who haven't yet cut their tailcones for the tailwheel mount...

I would encourage you to cut the slot wider (and longer) than you think you need to in the fitting process. I cut my slot originally believing I had left more than enough room around the mount to avoid chafing later. I had not wanted to cut too much out because I figured that would look sloppy. However, I figured this clearance when everything was only clecoed together. When I later riveted the tailcone, the rivets really sucked the skin up closer to the bulkeads and closer to the tailwheel mount. In fact, on one side of my slot, the tailcone skin is just barely touching the mount's weld where it exits the aft bulkhead. Although the landing energy will force the tailwheel mount up and away from the skin, I am still concerned about the potenial for rubbing over the long term.

Not sure there is much I can do about it now, but hopefully someone else can learn from this. In short, make the slot significantly larger than you think necessary.

tailcone slot

Did you use the template from the drawings? I am working on my QB fuselage and am about to the point where I will be installing the tailwheel mount and planned to use the template.

Hi Dave-
Yes, I did use the template, but (at least for me) that was only a minimal starting point. I had to take off much more than what the template original had me take off. It's sort of a iterative process. Cut it out, fit the mount, trim a little more, fit the mount again, etc. Part of the problem is that until everything is at least clecoed and bolted together (both bulkheads, mount, and skin), you don't really have a good feel for exactly where the mount is going to fit relative to the slot, so it's a time-intensive process. Then, when you rivet the tailcone together, everything will get closer still. Consequently, my advice is to leave a bigger gap than what you think you will need. I would cut it so that you have at least 1/8" from any contact before you start riveting.

FWIW, I was also stumped over how to rivet underneath the mount on the F711 bulkhead--since there's no way to get the bucking bar in there. Van's emailed that pulled rivets were OK for the tailcone but that since it was a taildragger, recommended that I use CherryMax rivets. Thus, I drilled up to #30 about 3-4 of the holes that I thought would be difficult to rivet and dimpled them before putting it together for the last time. I'm glad I did. Be prepared for some difficult bucking as you put the tailcone together. They were the hardest rivets I've had to date since the leading edge rivets on the HS. There's a lot of force working against you where those 2-3 skins come together and the angles at which you have to shoot and buck the rivets can be challenging. I ended up with no damage to the skin, but had to replace a couple rivets and have a couple more where the shop heads are not the prettiest.

Not sure if this is representative of the experience of other tailgear builders, but hope it helps. Good luck.

uk_figs said:

Did you use the template from the drawings? I am working on my QB fuselage and am about to the point where I will be installing the tailwheel mount and planned to use the template.

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Out of curiousity... does the QB come with the tailcone and rear bulkheads already put together? If so, how do you get the mount in there? It's such a tight fit that I don't think I could ever get the mount out now that the tailcone is all riveted together. ????

alpinelakespilot2000 said:

Out of curiousity... does the QB come with the tailcone and rear bulkheads already put together? If so, how do you get the mount in there?

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In my experience, the answers to your questions were:

1. Yes
2. Equal parts force and bad language



I ended up using CR3214 CherryMax rivets along the bottom too.

mcb