The cold weather has once again returned to Rough and Ready. It was beginning to look like we were about to skip winter. Now it's beginning to look a lot like Christmas -- That is, what Christmas would look like were I to live anywhere but California.
The following photo pinpoints for the first time, the exact cause of Global Warming.
Ahem.. Moving on now, before the CO2 police show up and arrest me for heating the Universe, I begin by retrieving the completed horizontal stabilizer from the loft. This is the first time I've looked at it in a year and a half. It's not too bad, but I can see that my riveting skills have improved some. No show stoppers though, so I proceed with the attaching the HS.
Bolt holes must be drilled through the longerons and some support angle in the tail cone and through some spacers that sit on top of the tail cone deck plate. I found this to be a little tricky because I was convinced that the best way to drill this was from the bottom with an angle drill. I don't remember why I got stuck with this particularly stupid idea, but that is how it went with the first two through the longerons. With your arms through the access holes holding and positioning the drill you can't see where you're trying to drill.
I finally got a little smarter and finished the holes through the HS forward spar located with a strap duplicator. Going this route, I could be sure the the holes would be plumb because I could see the drill. Before the holes are drilled the HS is measured against fixed points along the fuselage. When the tips of the HS measure the same on both sides the the horizontal stabilizer is straight and one should drill at once before anything moves.
Here Carol is helping me to measure. She enforces the measure twice before drilling rule. I get that mixed up all the time. More on this later.
And then we move on the the bolts at the HS rear spar.
And here it is all bolted down.
So now I move on to the vertical stabilizer.
The vertical stabilizer connects to the fuselage at the stabilizer's rear spar and the front of the stabilizer to the horizontal stabilizer's main spar through the F-781 attach plate. The F-781 comes from Van's as a flat piece of 0.063" aluminum stock. It is already cut to size, but the edges need smoothing and some holes have to be match drilled with the horizontal stabilizer. There is also a bend at about the midpoint to match the rake of the vertical stabilizer.
The F-781 attach plate has been the subject of much discussion on the internet forums because of some cracking of this part discovered in a few aircraft. In addition, one or two crashes have been linked to the loss of the vertical stabilizer. There is at least one company producing an aftermarket flange to beef up this area.
With all of this in mind, and with meticulous attention to detail and the fine craftsmanship of an elderly, but still quite sharp Swiss watchmaker, I set out to produce the best F-781 part yet committed to aluminum. It would the object of admiration across the aviation industry and would probably make the cover of "Aviation Week and Space Technology". I will be astonished if a finished piece this magnificent fails to catch the attention of NASA or Jay Leno or something similar.
Naturally, with plans this grandiose, the trouble will begin early. After the F-781 is match drilled to the HS, I fear that I may have clamped it in place incorrectly prior to drilling. Then, I decide that the holes actually are offset too high, but I still hold out hope that when the holes are drilled to final size the offset error will magically disappear. So I re-position the F-781 and drill to final size. In the photo below, it's an obvious FUBAR.
This part is definitely scrap, so I trace the outline onto another piece of .063" to make a replacement. The hole locations are transferred and I'm back in business.
And here are the two parts together.
To complete the new part I have to put the bend in place. It's a simple matter to match the old one if both are placed in the brake.
After this experience, I'm considering changing my long held belief that one should drill twice and measure once. So here is the completed F-781 in place. If the longitudinal dimension of the vertical stabilizer's forward spar requires it for a good fit, Vans allows a spacer to take up the slack. I was able to reuse the miss drilled F-781 for this less critical purpose so, all's well that ends well. (This may be the only builder's blog to quote Shakespeare).
I move on to attaching the read VS spar, which requires more match drilling. Here is Carol holding the vertical stabilizer prior to drilling the rear spar.
And now the four bolts at the bottom of the rear VS spar.
Transferring the hole locations from the tail to the rear spar was a bit of a head scratcher because of the very limited space inside of the tail. It made it impossible to match drill from inside. Transfer by paper template solved the dilemma.
And here are the four bolts installed.
And so here we are with the vertical and horizontal stabilizers attached for the first time. I can't attach the rudder as long as the plane is on the rotisserie, so that will have to come later. At this point there is nothing left to do on the HS and VS but take them back off in preparation for painting.
No comments:
Post a Comment