Tail Cone Fairing Question

[JohnF]

I thought I posted this before, but it didn't show up, so I must have clicked the wrong thing...

Anyhow, look at 12-10 step 3 that says, "Tap the called out nutplates half way through the screw hole per callout in Figure 1."

I am uncertain why you need to tap the nutplate which already has threads cut in it. Also, I am even more unsure of what " half way through" means when taping...

What did you figure this was all about?

 

[JBPILOT]

As I recall

I believe that is to make the screws go in a little easier. It opens the threads a little. If you go all the way thru, they will be too loose.

If someone else remembers otherwise, jump in. That was many months ago.

John Bender

 

[KRAUSEGB]

THAT WAS MY UNDERSTANDING ALSO.-- TO MAKE IT EASIER TO START THE BOLTS.

GARY

 

[Tony_T]

Tapping nutplates...

...with deference to the engineers, didn't seem like a great idea.
The intent is probably to be able to hand start the screws to hold the lower tailcone in place while the others screws are started. Being a little leery of ruining the holding power of the nutplates I just ran a screw into the nutplate a couple of times to ease the threads a bit.

Tony

 

[Slane]

Tailcone Fairing 12-07

On page 12-07, plans call for modifying a #27 drill bit by drilling 1/8 inch into concrete before completing step 6. Anyone tell me what this modification achieves and why it is necessary?
Slane

 

[Mich48041]

Dulls the drill bit

Drilling into concrete dulls the drill bit so that it will not catch on plastic and crack it. It is more important to use a dull drill bit on the canopy. Fiberglass parts do not crack as easily. I hope that you laid out the holes using revision page 12-05. The original drawing put the holes in the tail skin tabs too close to the edges.
Joe

 

[Slane]

Drilling into concrete dulls the drill bit so that it will not catch on plastic and crack it. It is more important to use a dull drill bit on the canopy. Fiberglass parts do not crack as easily. I hope that you laid out the holes using revision page 12-05. The original drawing put the holes in the tail skin tabs too close to the edges.
Joe

Thanks Joe. Seems a bit counter-intuitive, but good to know. I do have the most current revision, but it is always good to have a reminder to check for revisions.
Slane

 

[rvbuilder2002]

Drilling into concrete dulls the drill bit so that it will not catch on plastic and crack it. It is more important to use a dull drill bit on the canopy. Fiberglass parts do not crack as easily. I hope that you laid out the holes using revision page 12-05. The original drawing put the holes in the tail skin tabs too close to the edges.
Joe

The type of fiberglass the fairing is made of is somewhat soft like acrylic. A drill bit can grab and pull its way through it. A dull bit will drill more in a scraping action (like a unibit or plexi bit) and will drill a cleaner hole.