Re Build of N94978 BC12-d

[TimHicks]

Re: Re Build of N94978 BC12-d

I was in a hurry. So I bought one from airTex. It fit great. Lead time was a couple of weeks.
Drove me crazy (because I was in a hurry). But I'm glad I waited.

[astjp2]

Re: Re Build of N94978 BC12-d

I made my own...

[Leenicklas]

Re: Re Build of N94978 BC12-d

I appreciate all the rivet comments. They were very helpful in how to proceed. "Last" question: I'm trying to decide on a firewal blanket; A custom BC12D from Airtex vs a more generic one from A/C Spruce. Anyone had experience with either of these?

[astjp2]

Re: Re Build of N94978 BC12-d

So you didn't explore the link I gave you? And it takes special tools to crimp tublar rivets. You don't want solids, it will crush the boot cowl aluminum if you squeeze or buck them. That is why I said to use A series rivets. Tim

Thanks for all the info on rivets. When I look for steel rivets, all I find on A/C Spruce is A (soft alum) and AD (hard Alum). any suggestions for a steel rivet.

[Leenicklas]

Re: Re Build of N94978 BC12-d

Thanks for all the info on rivets. When I look for steel rivets, all I find on A/C Spruce is A (soft alum) and AD (hard Alum). any suggestions for a steel rivet.

[astjp2]

Re: Re Build of N94978 BC12-d

substitution of hardware is a minor

[Ragwing nut]

Re: Re Build of N94978 BC12-d

So were the wing rib rivets on a prewar, it was cheap and a machine punched them in, not anything special on the outside of your firewall

nothing special but not correct since we are going kookoo over regs in this thread.

[astjp2]

Re: Re Build of N94978 BC12-d

So were the wing rib rivets on a prewar, it was cheap and a machine punched them in, not anything special on the outside of your firewall

factory rivets were steel. I would not use aluminum

[astjp2]

Re: Re Build of N94978 BC12-d

If I remember the rivets you want are AN455, I would also use a soft rivet, the boot cowl is 3003h14 and very soft

http://rivetsonline.com/additional-information/ms-and-an-rivet-data.html

[Scott]

Re: Re Build of N94978 BC12-d

I used AN470 rivets on mine where needed. After bucking the shop head 80% I used a flat snap on the rivet heads to reduce the profile by about 30%, so the cowling chafe tape fairs better. I have not seen this method written up anywhere but Cessna frequently used flat snaps on universal head rivets. I never understood why, but they did, including on primary structure.

The steel rivet thing seems to be a Taylorcraft standard. Most firewalls use aluminum rivets and of course the boot cowl/firewall is not structure on the Tcraft.

Re: Re Build of N94978 BC12-d

I can look to verify tomorrow but I recall the originals were steel. But you are fastening to an aluminum boot cowl so that joint is probably limited by the boot cowl material either way.

The original rivets had shallow heads as I recall and maybe the only way to reproduce that is with steel rivets. I assume you want to reproduce the shallow head since the back of the cowl will sit there.

Dave

[Ragwing nut]

Re: Re Build of N94978 BC12-d

I'm in process of riveting firewall to boot cowl. Should I be using stainless steel rivets as opposed to aluminum.

factory rivets were steel. I would not use aluminum

[Leenicklas]

Re: Re Build of N94978 BC12-d

I'm in process of riveting firewall to boot cowl. Should I be using stainless steel rivets as opposed to aluminum.

[astjp2]

Re: Re Build of N94978 BC12-d

Well my cost is $68 for a non member to get the document....maybe I wont post it....but from reading the requirement posted from ACK, or was it AmeriKing, the 100 pound .1" deflection is the stiffness required to provide adequate shock to trigger the automatic function, the 100 G is the requirement to keep the ELT intact. My EBC weighs like 3 lbs, that means that I have to load test to 300 lbs in all directions. I might have to make a fixture to load test my installation...maybe it would be a good STC?

Re: Re Build of N94978 BC12-d

Tim,

Good find on the RTCA doc thanks, Dave.