BC 12 D with short mount C-85

[al Starner]

Hi all, Newby here. I've restored NC 95600 with a C- 85. I understand if I can find an existing 337 for the conversion from A-65 to C-85 and supporting data, I can get approval from FSDO. Plane flew with the C-85 at one time but FAA has no 337 on record. Can anyone help me? It may be possible an old field approval was done but no 337 filed. I also have some leftovers from restoration including a lot of Martin Clip wire. Anyone interested?

Al Starner
Penrose, CO
719 372 6238

[N96337]

Re: BC 12 D with short mount C-85

The previously approved 337 helps, but it by no means guarantees you an approval. There are a few out there, so that may help, and your relationship with your local FAA inspector will help as well. It's getting tougher and tougher to get things like that approved (unfortunately), but if you get enough supporting data, and jump through the hoops, it usually can be done. Try getting the FAA records for your aircraft... it might have the previous approval in there somewhere.
John H.

[Yellow Duck]

Re: BC 12 D with short mount C-85

I thought the 85 install was almost a slam dunk. Being they came out with an 85, it wasn't much more than a log book entry. At least that is what my IA says. (no names please) He may not be correct. But, I go with him and let him argue with the FISDO.

[crispy critter]

Re: BC 12 D with short mount C-85

Guys,trust me when I tell you that to get approval for the 85hp on a BC12D takes the same wing bushings,strut & butt fittings as the model 19. I spent almost a year trying to get it approved without doing the mods with no success.

[Jim Herpst]

Re: BC 12 D with short mount C-85

Tis tough these days no doubt. Thats why I am clipping the BL and leaving the other one I have BC paper work for as a really light long wing BC.

If you have a BL clipping makes perfect sence to me.(When again figuring how hard it is just to put a damn A-65 Continental in em with APPROVAL) Now if you have a BC12D (or a BC ) then I suppose the Gross weight increase STC is an option. Its a damn shame however that the light weight non electrical 85 is so tough to get approved. One could easily argue that in high density situations it is far safer also... Shame that common sence is not the order of the day with our government. Word GOVERN seems to be creeping up more and more !!!

[paulp]

Re: BC 12 D with short mount C-85

Hey Jim,

It could be worse. We could actually get the government we pay for! Then, we would really be up a creek!!!!!!!!!

[Jim Herpst]

Re: BC 12 D with short mount C-85

Paul,
Your right !! What a relief !! I'll cheer up now!!!!

[Gary Snell]

Re: BC 12 D with short mount C-85

Hi folks

This thread just caught my eye as I've been contemplating a conversion to an 85-8 in my current BC12D project. It appears that the STC may be the way to go, particularly if I want to increase the gross weight. I haven't seen the details of the STC, but would one have to do the complete F19 conversion or could I limit it to the fuel system and wing/strut fitting mods? I don't care about the larger baggage compartment as I'm past that point in the rebuild. Also wondering what's involved with the wing/strut fitting mods.

I would apprepriciate any comments/advice.

Gary Snell

[Dano"T"]

Re: BC 12 D with short mount C-85

This is a very common question here, and the answer is yes. You can make your BC12D a BC12D-85 with 1280 gross by installing the 11/16" O.D. wing spar bushings and either welding the reiforcement plate on your strut attach fittings or buy new F-19 fittings. Also, the wing root fitting is replaced with a thicker one. Several members have pictures that made me understand all of this very well..so click on these to go to some of the gallery photos. By doing these mods per the STC and keeping your stock short mount you will have the ultimate LSA in my opinion.

Strut Fitting Mod
Factory new F-19 Fittings with P/N
Factory New Butt fitting with P/N
Factory new butt fitting2 with P/N
Go to Pg. 5 of Rob Lee's Restoration of G-BREY
Rob Lee's shows the new bushings and the jig he used to drill out the old 7/16" bushings to accept the new 11/16" Bushings

[Sloanlow]

Re: BC 12 D with short mount C-85

Dano

Thanks for the pics that clears it up for me too.

Jim A

[Yellow Duck]

Re: BC 12 D with short mount C-85

Robert Lee's restoration is a great manual for restoring a T-Craft. Think I will with Robert's permission print this out, to use if I am ever able to find a T-Craft to restore or maybe restore the Duck in a few years.

How about that Robert ?

Really a great piece of work.

[VictorBravo]

Re: BC 12 D with short mount C-85

A recent post simply said "buy new F-19 fittings". Is that something you can go down to Wal-Mart and pick up off the aviation parts shelf?

[Gary Snell]

Re: BC 12 D with short mount C-85

Thanks all for the responses. So if I limit my changes to the BC12D-85 conversion, would I still use the Harer STC or is this simple enough for just a 337?

[VictorBravo]

Re: BC 12 D with short mount C-85

Thanks all for the responses. So if I limit my changes to the BC12D-85 conversion, would I still use the Harer STC or is this simple enough for just a 337?

If I had it to do over again, I would bypass the Harer STC because of some problems and discrepancies, and do my own 337. It is well understood by the FAA and Taylorcraft experts that the three legitimiate modifications needed are the 11/16" spar root bushings, the upgraded spar fittings, and the 3/8" fuell ine from the tank to the gascolator to the carburetor. This assumes you have FORWARD-facing pitot-vented fuel caps on the wing tank(s)

If you do the Harer STC, you will be asked to install several redundant vent lines (with no supporting documentation), add fuel tanks you may not want, move the fuel valves to an less safe location, weld or solder on a main fuel tank, and possibly be talked into adding mysterious wafer thin plywood doublers on your spars that nobody understands or wants to discuss.

There ARE 337's out there for an 85 horse engine. Get a hold of a copy of one (Flyguy???) and do your own 337 form proposal using the pre-existing one as approved data IMHO.

If you can find a set of F-19 spar fittings, either from Forrest or the Taylorcraft factory, this will save time and effort. You can make up the bushings from "micarta" or "phenolic composite" material called Garolite. The fuel lines are standard hardware off the shelf or order from Aircraft Spruce.

You will be removing at least 25% of the fabric from your wings. While you are doing this, it might be better to just re-cover them, because it is more work to repair fabric than replace it in this case (IMHO). If you have a post-war wing with the wire clips it should be an easy choice to re-cover the wings. Use the opportunity to do a full, complete and detailed inspection/repair on all internal wing components. Have a close look at the spars, particularly near the attach fittings and strut fittings. You need to look at the top (narrow) edge of the spars, not just the wide faces.

If you want, I will send you my compilation of notes and experiences doing this modification recently. Others in this group have more experience as well.

If you want a 1500 pound gross weight airplane with an electrical system, buy the Harer STC and be prepared to take your airplane apart further than it really needs to be.

[Gary Snell]

Re: BC 12 D with short mount C-85

Thanks Bill for your words of wisdom. I like the 337 idea myself and will probably pursue that avenue. Any help from a member that can provide a copy of their 337 for an 85 conversion would be much appreciated.

Gary Snell