PA-12 questions

[PerryB]

I have a PA-12 that's going into the shop this fall for fabric, paint and general re-furbishing. It has pretty much all the popular mods, but I am interested in the Wipaire 1935# gross wt. increase. What is involved in doing this? Also, I had an idea but don't know if its reasonably do-able or not... what about a two piece door accomplished by having the lower half hinged at the front (like a car door), and the upper door would be very similar to a PA-18 upper. I saw a Citabria like this once but don't know if it was factory, field approved or what. I currently have a plexi sea plane door but its not great for flying with it open. The lower part of the door opening creates a lot of drag and interior buffeting. If I were ever to engage in float operations I could just put the original door back on. Thanks!! --- Perry

[8GCBC]

I could not find a PA-12 gross increase from Wipaire?

Only PA-18:
TC Number -- Make -- Model:
1A2 -- Piper Aircraft, Inc., The New -- PA-18A-"150"
1A2 -- Piper Aircraft, Inc., The New -- PA-18-"150"
1A2 -- Piper Aircraft, Inc., The New -- PA-18AS-"150"
1A2 --Piper Aircraft, Inc., The New -- PA-18S-"150"

[Utah 12 Driver]

Ron Sullivan has the STC for the gross weight increase for the PA-12, its quite a bit of welding involved. I spoke with some of the Pro's who are on this board and was advised against it. He has the Flap STC, Lower extended baggage. I forgot who has the upper baggage maybe be Ron as well. He is the guy you want to speak with if your cutting into a PA-12 project. Last number I had for him was 907-345-4630. He knows these airplanes inside and out. Charlie Center also has a lot of knowledge Crosswinds 907-376-8069. You can beat the advise of the people on this board.

I hope this helps

[sierra bravo]

Crosswinds (Charly Center) #SA689AL and Rodger Borer (estate?) #SA190AL hold the 1935# gross weight STCs. The most notable change is the formers at the turtle deck are replaced with structural tubes. My -12 has the Crosswinds version.

Depending on the condition of your airframe you may be better off buying a new, modified airframe from Univair.

I've never heard of the door you describe but there are a few -12s around with split Cub-style doors. Cubs Unlimited on this site has posted pics of this mod in the past. Very nice if that's what you're after.

[Paul Heinrich]

Wip's "1935 gwi" for a 12 only appears in its float STC and it only applies when the 12 is on Wip floats and the plane's gross goes back to original 1750 when it is on wheels.

Also, it my understanding that if the 12 has FAD 60 gallon tanks, the plane is not eligible for any gwi modification.

I have a letter somewhere from the current 12 TC owner which clearly makes that point.

[skywagon8a]

Also, I had an idea but don't know if its reasonably do-able or not... what about a two piece door accomplished by having the lower half hinged at the front (like a car door), and the upper door would be very similar to a PA-18 upper. I saw a Citabria like this once but don't know if it was factory, field approved or what. Thanks!! --- Perry

The two piece on a Citabria is, or was, a factory option.

[mike mcs repair]

crosswinds, so in general:
every bay in the back half of fuselage gets 'X''ed with a 3/8" tube.
then some more x stuf going up in front of jackscrew to top stringers,
top side stringers get replaced by welded tubes
tube added across tops of some of the ginger bread stringer holders, plus some replaced?
gussets added at rear door posts....
probably a few more tubes I am forgetting....

so it's a lot of weight you are adding....and allot of welding.....

[sierra bravo]

To the door question and the potential for incorporating a split door, take a look at several -12s and you'll likely see that the door frame shape isn't exactly consistent. Many -12s have had the door sills squared off and no two appear to be the same in my own observations. The shape and height of the door sill will determine whether the lower door can drop down without interfering with the struts. The whole exercise would require that the upper door be flat so consider where the lower door would terminate to allow the upper door to be flat. Is there room? I might could have made mine work but it wasn't a detail I cared about. Warm weather guys are probably more motivated. Maybe the forward swinging lower and top hinged upper opens up the options for maintaining a lower sill. Interesting thought. Not very practical for anyone who may operate on floats or who wants to hand prop. Interesting just the same.

It seems more feasible to incorporate a swing-up panel in the top of a typical seaplane door. That would be fairly simple to build. Watch that hinge point so your door or window panel doesn't compress the sump drain when it's open!

[cubunltd]

A few pictures of the PA18 style doors on a PA12

[cubunltd]

Couple more pictures of PA18 style doors

[PerryB]

Thanks for the input, everybody. It looks like the GW increase is out. As far as the door, the swing-up panel in my existing door is going to be the way to go, I think.

[N5126H]

I agree that no two 12's are the same. There is always something different in the basic measurements, especially around the doors. I had a swing up glass door with a swing up glass (plexi) window built within the door. It was very nice. I could fly with the window open, just like a cub, yet the whole door also went up and latched. The boys at Dans Aircraft in Anchorage built it for me. Latch pined the door in three places.