Wing attach fittings

I recently purchased some wing and gear attach fittings for my Experimental PA14 project from Cubparts@aol.com. John, the owner, says that he has the type certificate for both the PA12 and PA14 and is making parts in Canada for them. I don't know if they are certified but for my project it didn't matter. They seem to be well made. Along with the parts came some very nice instructions on how to add them to the fuselage frame. The following picture shows the alignment blocks and 5/16 drill rods that help with the alignment process. I first measured the front to back distances, then the side to side, leveled both sides, and then checked things with the trammel points. I thought the whole process really went quite well considering the complexity. The distance between the rods is exactly 1.5" center to center so that means that the attachment holes are also that distance apart vertically.

I like that,

might need to use that method for bad retrievals...
anyone know what the dimension would be on an 18 (like the 1.5" on the 14)

so how do you tell that that "perfect square" you just made is perpendicular to the center line?? (so one wing isn't ahead, even though they are strait across)

another set of holes in each block, and strings extending centered in holes both sides to tail area, see if tail post is centered? maybe??

I don't see how you can attach those brackets without a jig. Seems to that the tail and motor mount along with the wing attach brackets needs to be in perfect alignment for everything to work correctly.

Tim

For my exp. 14 I built two "short wings", each with a butt rib that slides onto the spars and a couple of spreaders between the spars. I am building mine with wood spars so I made these "spars" about a foot long with all the proper wing attach hardware on the end of the spars. I used these wings to establish the proper front to back spacing along with the proper AOA and made sure that the leading edges were the same on both sides. After welding on the wing attach fittings, I used the "wings" to correct some alignment issues that crept up after tack welding. It was real nice to have them slide in for a nice fit after all welding was completed. The "short wings" also came in handy when I built my bird cage. I ran strings across the ribs and simply used the strings to establish the top of the bird cage, curves, etc. I will mount them again soon to set up the pulleys and other wing root needs. They have been very handy "tools". If interested, I have some pictures on my web site at www.xanga.com/martyfeehan You will have to go back a page or two, I did that step last summer.

Marty57

The fuselage was built on a level table with the upper square leveled. The center line of the front and rear of the square was lined up with the horizontal reference line of the frame which ran from a prescribed location on the tailpost to the reference postion on the engine mount bulkhead.

just some quick math fun... these are aprox but what i used, no time to look up..

but to show the amplification of any error here....

31" between spar fittings, 198" wing......

so each 1/16" a fitting is off left to right in relation to the center line moves wing tip 0.39903788125" (almost 7/16")

if someone has the right dimensions i will plug them in...

or my math could be off.... but I am using the cad program...

oh and for fun, if its an 1" off that's 6.3846061"

oh and if that's a perfect square, cocked, does that mean the other wing equally goes the opposite way... so our error is doubled??

but i really like those first pictures...gave me a great idea for a tool....