Quick Question - F-794A Lower Empennage Fairing

I am working to install the Lower Empennage Fairing and have drilled and tapped the holes along the Longeron to 6-32. It then says to use #6 CS screws to attach. Should I be dimpling the Lower Empennage Fairing as its only .025, and then countersinking the fuse skin / longeron, or should I try to counter sink the .025 for a #6 screw the best I can, so that I don't have to do anything to the fuse??

Thanks,
Chris

I dimpled the fairing on mine and countersunk the fuse.

Tap the longeron before mounting the F-714 aft deck?

Hi All,

I'm about to rivet the aft deck in place, and stumbled across the fact that I have to eventually screw the F-794A to the side of the longerons. This will mean that I've got to drill out some perfectly good rivets . Fortunately, I'm getting pretty good at drilling out rivets (don't ask), however I thought I should probably drill them now whilst I have good access to the aft area. I was thinking that whilst I've got some good access, I should probably not only drill these out but also do the countersinking and tapping of the longeron for the #6 screws. Thus I have two questions:
1. Is countersinking this and tapping for screws still the best method of fairing attachment?
2. Is there any reason why I shouldn't drill, countersink and tap the longerons now whilst I still have access?
Cheers,
Tom.

Do it now. I did not rivet the holes but waited to drill and tap. It's possible after the empennage is installed but not nearly as easy as doing it now.

Also note that when fitting those lower fairings, you can opt to omit the seal if you take the time to get a better fit.

You will never need to remove this part in the future. I riveted it in place rather than using screws. Just remember to leave and tap the screw holes for the inspection cover in the rear of that fairing. And as Ray says leave the seal out.

MarkW said:

You will never need to remove this part in the future. I riveted it in place rather than using screws. Just remember to leave and tap the screw holes for the inspection cover in the rear of that fairing. And as Ray says leave the seal out.

Click to expand...

Right on the nose!

I was going to chime in with the same message.

Don't work harder than you have to.

CJ

Excellent. Thanks for your responses. My concern is access later if I choose to rivet these, will I have access, or are people just putting in MK319BS rivets?
Tom.

I just answered my own question. I can crawl up the tail cone and buck those forward most rivets. This AN426AD3 rivets will work. The problem will be that you will be driving a rivet over a painted surface, assuming you paint the fuselage and fairing separately before final assembly. I guess that's why Vans has this as a removable item.
Tom.