PA-12 mods: how much will this welding cost?

[Andy505]

Hello, everyone.

I'm starting off a PA-12 refabric, and before I buy the STCs for the pa-18 style seat, max gw increase, and flip up (stbd side) door & possibly a PA-18 front seat, I was wondering: how much time, money, and weight do these modifications cost?

Does anyone have any recent experience with this?

[MT12]

Hey Andy; a couple of 'on my high horse' comments, then on to your question. First don't hesitate to do the mods you want now while it is uncovered and easy, you may cringe at the cost now but will thank yourself later. Remember the stingy man suffers the longest.

as far as mod costs go, don't even worry about the cost just do the safety mods regardless including: x brace over the piliot (STC $255 from Dodge-welding less than $100-maybe a pound); seat belt attached to floor, (easily done, well worth it- Univair charges $181 when you buy their fuselage-less than 1/2 pound); rear pax shoulder harness atttach point- 1/4 lb.-easily done and cheap but best done while adding the pa-14 cathedral over the baggage area to eliminate the cross tube (atlee stc $250 for the cathedral, shoulder harness attach point about $25 worth of welding, welding for the cathedral itself guessing I paid around $250 cathedral maybe a pound.

The pa-18 seat is a whole kettle of fish with the cross braces, pa-12 bungees etc, plus the outrageous cost of the seat itself, I like my 18 seat in my project 12 because its adjustable and I am 6'3", but I do just fine in my flying 12 with the original seat and no adjustment.

I have the gross weight increase but had univair put it in when they build up my new fuselage so I can't tell you a cost for it, they didn't charge me much for it since they were building the whole fuselage but its lots of tubes, lots of grinding and definately additional weight but I can't tell you how much. guessing 10-15 lbs.

Seaplane door not much work or cost at all, cut off the old hinge points, put a brace at the top of the door in the fuselage to attach 1/2 of the piano hinge and you're on your way- I needed to add to small brackets on the door frame for the gas shocks, 30 minute job-after I spent hours trying to figure out how a gas shock system works best. maybe a pound or less.

Another semi-safety mod is the 1" seaplane tube up the front of the left window from the gear attach point to the front wing attach point, I don't think there is an STC on it since it was part of the type certificate of the pa-12S, tho it does take lots of cutting and weldoing.

When I did hire a welder to do my work for me, I reduced my costs by doing as much of the grunt work as possible such as cutting tubes to length, fish mouthings them and lots of grinding..

YMMV.

doug

[algonquin]

I have a frame that was banged up quite a bit. I took it to a welder with a jig, bought several STC's and for about 6000.00 got back a beautiful frame all mod'ed.i have a little over $7500. Or so in everything. All the mods I had done were improvements to the design and many for safety, like the X brace in the overhead. Like the above post said do everything now it will save you in the long run. Good luck.

[JimC]

How difficult is it to do the seaplane door mod to a 12 that is already covered?
Where can I purchase the STC?

[av8rtom]

I just did all that stuff and more to my 12 and one thing that I am still having a bit of trouble with that you might consider..., with the super cub front seat (folding and sliding from Atlee), I had to bend the rear stick back a little so that it would'nt rub the front seat when it's in the back position (where it usually is). Bending the stick back solved the seat rubbing problem, but if you get anybody with a gut in the back seat...., well you get the picture.

[Andy505]

How difficult is it to do the seaplane door mod to a 12 that is already covered?
Where can I purchase the STC?

I can answer part of that question.. the seaplane door stc comes from Crosswinds STOL.

Sent from my SM-G870W using Tapatalk

[Gordon Misch]

I can answer part of that question.. the seaplane door stc comes from Crosswinds STOL.

Sent from my SM-G870W using Tapatalk

There is considerable structural modification under and behind the door opening. Not possible with the cover in place, however it might be possible to peel some back for access.

[MT12]

Gordon, are you referencing the left side door, or just making the right door hinge at the top? I was just referencing the top hinge in my response. The right door hinge should be a piece of cake while covered, no structural changes at all.

doug

[Gordon Misch]

Gordon, are you referencing the left side door, or just making the right door hinge at the top? I was just referencing the top hinge in my response. The right door hinge should be a piece of cake while covered, no structural changes at all.

doug

I was referring to the Crosswinds "cargo door", which I installed in place of the stock door on my -12. Sorry for the confusion!

[MT12]

I am easily confused, I learned about that mod a bit too late to have Univair ad it in when they were building up my fuselage, I would have been handy at times for big things but then again I don't haul that many 55 gallon barrels, oh wait, I don't haul any 55 gallon drums-ever.....

[JimC]

I was asking about the top hinged right hand door. Exterior is covered. Interior is bare tubing.

[Gordon Misch]

Jim, if you're interested in the Crosswinds door, trusswork is added below and aft of the revised door opening. Fabric would need to be peeled back in that area. It sure does make getting into the back MUCH more pleasant.

[JimC]

Thanks, Gordon. Would make entry after propping a lot easier too.
Sounds fairly doable. Plane is covered in Razorback and butyrate.

I'm assuming the door work is to clear the struts when opening?

[stewartb]

A typical PA-12 seaplane door doesn't require any airframe welding except to add a stud for a gas spring. Build a door to fit the opening, hang it off the header of the opening using a stainless steel piano hinge (make sure you have clearance to open it and not hit quick drains), figure out how to latch it, and snap in an appropriate gas spring.

http://www.supercub.org/forum/showth...vice-amp-ideas

[JimC]

Thanks, Stewart.

[Gordon Misch]

I'm assuming the door work is to clear the struts when opening?

Yep, it's considered preferable that the door clear the struts. The Crosswinds door comes straight down in the back. Works fine opened in flight, with one gas spring/shock in the front.

All you get with the STC is the drawing; everything is fabricated so there's a little bit of opportunity for ingenuity. I used MS20001P aluminum piano hinge, and redesigned the latch mechanism, which works real well. One caveat - Charly Center noted in handwriting on my drawings that they are approved for PA-12, although the printed documentation says PA-14. He told me on the phone that was the original intent and approval, but somehow the drawings omitted the PA-12 notation. My IA was satisfied with that.

I can send you some pics of mine if you'd like.

[JimC]

Gordon, please do.
jrccea1 at gmail.com
(that's a digit one after the a
Thanks

This from Charly Center this afternoon.
Sounds like a winner to me.
"There is basically no structure modification, I recommend making a new door out of 1/2" chromoly tubing or try and make the original door work. You have to make a latch system to hold the door shut fore and aft".

[MT12]

here's pics of mine, I just riveted the piano hing to the top header, and riveted the other side of the hinge directly on the door. The gas shocks took some head scratching, I finally just went to the parts house and got a 25# rated one and made it work-no coincidence I picked the cheapest one on the wall to start with. I just welded two tabs to either side of the door frame for the other end of the gas shock, Caution the door swings down with some geometry that I didn't understand-I put the first shock on and it fit great, I took it off and put the second shock on and it worked great, but when I put them both on together the door wouldn't close the last 4", I had to relocated one of the mounting holes by 1/2" and it works great (brought to you by science! Geometry I believe but I slept those my formative years so I am not sure) Note the second hole in the fore mounting bracket, so I recommend don't trim your tab til it fits right. The other end of the shock just mounts via its supplied mounts right to the original door frame. I am using a handle off of a pickup topper for the closure, works great albeit a bitheavy. All of this with an original door

[Gordon Misch]

I'll take some pics tomorrow. MT12 I did a fair amount of papermath to figure out the strength and geometry of the gas struts, but they work just fine. I'll get some measurements and part #'s also (MacMaster Carr for the gas strut).

[skysigns]

how hard is it to in stall a ingress gross weight

[JimC]

Got any photos of the latch mechanism?

[Gordon Misch]

Got any photos of the latch mechanism?

No, but I'll get some for you tomorrow.

[mike mcs repair]

how hard is it to in stall a ingress gross weight

TONS of welding.......

[Andy505]

Thanks for the feedback, MT12.

[Andy505]

Thanks for sharing, I'm going to save that for later reference on my own project..

[Gordon Misch]

Here's some pics I took of my installation this morning, I hope the dimensions are readable! The latch handle is fabricated from 3/8 tube, and the inside / outside handles telescope to facilitate installing the plexiglass. I forgot to look at the part number for the gas shock/spring, but I can get that if anybody wants it.

The hole that the latching rod goes into is a piece of tubing welded into the structure. Getting that properly aligned for low friction was a bit of a pain, but worth the effort.

[Scooter7779h]

The left side door STC requires a LOT of work. Move trim to skylight, move fuel lines & valve, move flap handle forward and down on floor among them. Ask MCS Mike & SB. That said, I LOVE dual entry doors on this -12. Nearly invaluable when doing river work on floats. I always enter through it so I don't have to climb over ski pump. Great for loading big stuff in or 2 passengers. I highly recommend if doing rebuild especially if ordering a new fuselage like SB did building up this one.

https://www.dropbox.com/s/0dfqq5toey...31155.jpg?dl=0

https://www.dropbox.com/s/j1ea5b5db9...31236.jpg?dl=0

https://www.dropbox.com/s/m2vsnestsh...31259.jpg?dl=0

[mike mcs repair]

couple albums full of -12 stuff in my picasa.... https://picasaweb.google.com/101445937433180427570

slippery slope doing a -12.... lots of mods, and well as, we are doing this, so we might as well do that, $$$

[stewartb]

That slippery slope isn't unique to -12s!

[Skip]

Gordon what did you make your door frame out of?

[Gordon Misch]

5/8 X .035 4130 square tubing from AC Spruce. It's what the STC prints call for.

A little more info; here's the McMaster Carr packing slip for the gas strut. I tried both 50 lb and 60 lb and prefer the 60, although the 50 is fine.

[qsmx440]

couple albums full of -12 stuff in my picasa.... https://picasaweb.google.com/101445937433180427570

slippery slope doing a -12.... lots of mods, and well as, we are doing this, so we might as well do that, $$$

One of the most fun things I have learned to do on my build is press forming (aileron/flap parts). 100 dollar Harbor Freight 20 ton press, 90$ Harbor freight air over hydrolic ram, chunk of horse stall mat and your in business. Great fun!! I cast aluminum dies for mine but I also found for a few items a piece of press board works as long as you place a stiff piece of metal between it and the ram. Good pictures Mike!

[Andy505]

Thanks, Algonquin. Being Canadian, things will cost a bit more here, but this gives me a starting point. I don't want to take the fuse apart until I'm as sure as I can be that I can afford to put it back together!

[mike mcs repair]

One of the most fun things I have learned to do on my build is press forming (aileron/flap parts). 100 dollar Harbor Freight 20 ton press, 90$ Harbor freight air over hydrolic ram, chunk of horse stall mat and your in business. Great fun!! I cast aluminum dies for mine but I also found for a few items a piece of press board works as long as you place a stiff piece of metal between it and the ram. Good pictures Mike!

some great metal working books here cheap https://www.youroldtimebookstore.com

[MT12]

The original question ask what will all of this weigh, I knew I had weighed my new univair fuselage but for the life of me I couldn't find where I put the note. Found it today on my bulletin board-who would have thought to look there, comparing the weight of my new fuselage to the old it was 12# heavier-using a certified bathroom scale. Mods include: gross weight increase, weld on float fittings, overhead 'X' brace, pa-14 cathedral; 1" seaplane tube on left side; rear fuselage square bracing. that was before paint