Experimental 12 Build

[DragginTail01]

Here's another build log, and place I'll be asking the community a lot of questions! If you have any opinions or suggestions during the build here, please feel free to share.

This is an experimental -12. Consider it a "barn find" / tear down/ build.

I've had my friends at Dimension Three out of Chico, CA do the cleanup of some could-be-better welds, and some big welds for some of the popular mods. Tail X brace, baggage door, lower extended baggage cathedral.

More to follow

 

[stewartb]

Fun! Gonna do a high performance -12 or leave it closer to stock?

 

[DragginTail01]

Going high-ish performance! Leaning towards an O-320 with 9:1 compression. Also flaps and VGs.

 

[cubdriver2]

Welcome, your going to need to do more mods to get that mattress to fit.

Glenn

 

[DragginTail01]

 

[stewartb]

I figured you meant an X brace over your head. Never seen the X in the tail. A box is more common.

I finished a cool -12 project about 12 years ago. It would have been more fun in the E-AB category. My advice? Use a short engine mount.

 

[DragginTail01]

Thanks for that! Are you flying your 12 much? Do you have flaps or VGs?

 

[stewartb]

Sold mine 10 years ago. That owner is a member here and he flies the heck out of it. He’d be a good resource to talk to. Not many guys have as much -12 time as Scooter7779H. And look up MikeMCSRepairs’ photo album of the -12 he built for member PA12drvr after he helped finish mine. That’s another very nice -12.

Yes, it has flaps and VGs, Cub tail, Cub gear, etc. Good performing -12.

 

[PerryB]

Be careful, nothing good ever came out of Chico, CA.......

 

[skukum12]

One often overlooked mod is what I call a tummy tuck. Take that rounded gingerbread at the bottom of the boot cowl and flatten it out. The reason for this is that in it's normal configuration it is always in the way of landing gear bolt access, which causes scratches and damage to the boot cowl. Also once the boot cowl is flattened down there, it looks a lot better.

 

[DragginTail01]

Thanks for that- I’m not quite sure what to change here- can you clarify a bit?

 

[Paul Heinrich]

Bill Rusk’s build thread hammers home the most important issue—“count ounces for every ounce counts.”

 

[DENNY]

Are you going to stay with stock gear or go to cub gear? If you change you will need some more welding.
DENNY

 

[DragginTail01]

Denny, can you be more specific? The plan is definitely -18 gear. Thanks

 

[DENNY]

I saw 12 gear in the pictures, did you get mounts for the Cabane Vee welded in? If not you might want to get the gear and Cabane Vee before you do to make sure it all fits not all gear is made the same.
DENNY

 

[DragginTail01]

Denny,
As I understand it, it has -18 gear. I'm not a cub pro, so take what I say with a grain of salt, but there is a cabane vee. Take a look at the 1st picture with the mattress in it. What i need to figure out is how to get some aft float fittings to weld on for less than the certified $750/pair!

 

[DragginTail01]

It appears every Supercruiser that's been well looked after has had the overhead x-brace installed. Are there any conflicting opinions on this?

 

[DENNY]

OOOPS I missed that first pic. Is this a Smith airframe? Before you get too far put the wings on and measure all the angles and dangles. If anything is not correct fix it now before fabric.
DENNY

 

[DragginTail01]

I think it could be a Smith airframe, but to honest I don't really know. It was owned by someone at Backcountry Supercubs a while back, but it traded hands quickly and he doesn't remember much about it. I think it was probably a Smith frame that sat in the back of the proverbial shop as it went to TurbineCubs and now Backcountry.

The wings are Dakota Cub. They're helping setting me up with a flap kit and an overhead johnson bar. Wilco on the angle of the dangle! Thanks for the input, glad to have the expertise of you guys.

 

[stewartb]

Everyone I know who does a full -12 build does the overhead X brace. It makes the lumps on your head even on both sides.

Why overhead flap handle? Are you doing a push rod flap system? Doing PStol flaps? That would be a GREAT mod on a -12.

 

[cub12]

i don't think it's a smith 12, i have built 2 exp 12's one was a smith and the second was built at javeron when he was contracted by what was TCOW now BCC. Send me a PM if you need some parts, i still have some left overs. I will second the short mount, X- brace roof, pa-14 dog leg, modify that one to have the removable brace behind the rear seat, 3" ext pa 18 gear and VG's.

 

[DragginTail01]

cub12, beautiful example! Great to see a working one with all the mods. What floats do you use?

 

[cub12]

i had one on a set of bilmar 2300's and one on a set of TF 2300's.

 

[Paul Heinrich]

I have never seen this “X” brace. What purpose does it serve?

Also, on the very first photo (with the mattress), it looks like there is a left hand clam shell door. Will the bottom half of the door clear the wing lift strut? It doesn’t look like it from the photo.

I agree that you should completely assemble and rig the plane before you cover anything.

I vote for using the original length motor mount.

Good luck with the project.

 

[cub12]

The short mounts make it tight for space between the FW and engine for sure, depending on the type of filter adapter being used a dog bowl in the FW may be necessary, but moving the C of G aft is worth it! To keep the PA12 lines i used a 4" prop extension from Saber manufacturing to bring the prop back out to it's original location but that was purely for looks.
My 2c only
Marc

 

[stewartb]

Other mods that I did and would recommend- Lower the cables so you can do a full flat floor all the way back. Removable bars for the back seat (all three). I used a metal floor and liked it. Would probably do carbon fiber now but would want a non skid surface. Supercub pilot seat is adjustable and easy to put the battery under it. I liked my dual seaplane doors. Liked the kydex interior. I did D windows and a metal headliner but would do L-21 glass if doing it again. Love it in my new Cub, but I don’t live where it gets hot. Think about how you’ll ventilate the cabin. Not the easiest thing to do in a double door -12.

Have you thought about moving the rear wing attachments to mimic Supercub AOI? I wanted to do it but it wasn’t practical at the time.

 

[DragginTail01]

Paul,
I figured if i throw in enough tubing I could save some money on fabric.

(kidding...its to beef up the tail for a bigger tailwheel and future-proofing as much as possible, for poor (yours truly) pilot technique in the backcountry)

Experimenting with the experimental!

 

[PerryB]

One often overlooked mod is what I call a tummy tuck. Take that rounded gingerbread at the bottom of the boot cowl and flatten it out. The reason for this is that in it's normal configuration it is always in the way of landing gear bolt access, which causes scratches and damage to the boot cowl. Also once the boot cowl is flattened down there, it looks a lot better.

https://dm2306files.storage.live.co...dMQ/IMG_3498.JPG?psid=1&width=1511&height=849
That explains something I never quite understood. I've seen 12's that look thin and 12's that look fat. Mines in the thin camp (wish I was). Most of the mods it has were done before I bought it.

 

[NWCruiser]

Im joining this build and have some questions as well. I see above, two of you have advocated for short engine mounts, and one for the stock mount. We are going for a 2200 lb gross with the Javron wing. Trying to do as much research/math as possible to figure out if a short engine mount will allow for a full 2200 pound plane without falling out the back of the cg envelope. opinions here?

 

[NWCruiser]

in related news...the wings on the wall in these pictures are for sale. They are certificated, never covered -12 wings. Since we will be using the Javron kit, we can't use them. Any interest?