flyingfever

[] Hey all:

Anyone else out there have any experience building the PT-40 replacement wing kit?

I originally built my PT-40 with the "A-style" trainer wing. Big mistake. Way too much dihedral.

I cut the wing in half with the idea that I would rework it to something more reasonable, but then thought better of it.

So I ordered a replacement wing kit from Great Planes with the intention of building a "B-style" sport wing.

Part way through the build, I am finding the die-cut center rib #1C seems to be too tall to fit properly.

By the plans, it seems this rib should fit down flush with the tops of the AJ and TEJ, and the underside should be up, flush with the bottoms of AJ and TEJ. This would allow the 3/32" sheeting to lay flat in these areas.

However, the rib #1C is too tall to hold flush as described above. In fact, it fits flush with the tops and bottoms of the main spar and trailing edge. No room for the sheeting.

Now, as I look at the old wing, the center rib is much more shallow and the sheeting does lay over it top and bottom.

I guess the solution is to rework the rib, but I don't want to jump to conclusions and cause more grief down the road.

Inquiries with Great Planes have produced no results.

Any one else have an idea?

'Fever

w8ye

My Feedback: (16)

I was trying to look in the manual and I could see everything you talked about in the pictures. Only thing is there were three sizes of PT planes at one time and those pictures might not necessarily be the 40. In one picture I can see it appear even with the spars and then later I can see the sheeting butted up to itself at the center.

The manual makes no mention of of the size of 1C.

It sounds as though you are experienced enough to adjust the size so it will work the way you want it to.

It will work best with the sheeting butted to itself. The main reason is that there is a curve in the top sheeting at the center. Their method is to sheet the wing halves separate and let the excess sheeting hang over at the center point whereby it is sanded off flush with the rib.

flyingfever

Thanks for the input w8ye.

After studying the plans, and reading, and re-reading the instructions, I determined that the sheeting is, (as you suggest) supposed to lap over the top of the center ribs. The real clue was in the text of the instructions.

That means the #1C rib is in fact too tall.

So I cut it down to size and got on with the build.

I went with the bolt-on wing design this time, instead of the rubber bands. But I left the dowels in the fuselage, so in the future I can go back to a rubber band wing if needed.

The wing looks good. Just needs a final sanding, and it is ready for covering.

Once complete, we will have one more trainer available for use at the club.

Thanks again for your advice,

'Fever