(page 23-04) The bigger-hammer approach...                   

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...to aircraft construction actually works, it seems.  After all the pounding, twisting, bending and spreading in a vise, the longerons fit well.  I'm deliriously happy to be done with them.  There's still a fair amount of match drilling into them, but no more bending.

It finally occurred to me that I could store the tail cone (seen here resembling a skinny aluminum tepee) by standing it up, thereby taking up much less space.  I'll need the space for the wing build.

I've decided to skip ahead to sections 27 and 28 (brakes, rudder pedals, etc.) which should be considerably easier without the side skins installed.

(page 20-05 revisited) Landing gear service bulletin.........          

Since I've yet to acquire the finish kit, the parts I received to comply with the Main Landing Gear Service Bulletin consisted of a small additional bracket connecting the center channel to the newly beefed-up side skin (at least it'll be beefed up when I install it), skin doublers (and triplers), and some CherryMax rivets to replace the now-drilled-out LP4-3s and to install the doublers.  CherryMax rivets have approximately four times the shear strength of LP4s.

The complete kit for the service bulletin will include massively beefed-up bits which attach the landing gear to the center channel.  The end result will be a much stronger landing-gear structure, which should put an end to the wrinkled side skins which showed up on some -12s after hard landings (mostly on grass).

The yellow arrow in the picture shows the new bracket with CherryMax rivets installed.  Some builders report being able to set the stronger rivets with their existing pullers.  Not the case with me.  Neither the pneumatic nor the manual puller would work.  I therefore ordered the Cherry G27 puller (shown in the picture) which, of course, performed the task admirably.  I'm always looking for an excuse to buy a new tool.

(page 23-02) Long(eron) nightmare..............                        

All of the horror stories about bending the longerons turn out to be true.  It's the biggest PITA so far by a wide margin.  I bought Larry Buller's dies, which I think are well worth the money (somewhere in the neighborhood of $47), so I was feeling pretty confident.  Pounding the bejesus out of the aluminum as put forth in the build manual didn't strike me as a good procedure either for spreading the angle or making the lengthwise bend.

The first step, after making the initial length cut and making the various marks on the extrusion, is to spread the first foot or so of the angle to 95.4 degrees.  Most builders, it seems, are using one of the plastic angle finders sold on the aviation aisle a Lowe's.  I drew the angle on a sheet of paper, using a protractor which had, in a previous life, been used to find elevation angles for communications satellites (hence the lines drawn on it, and, yes, I'm that cheap.  I hung the protractor from a paper clip and sighted along the lines).  I then bent a small length of aluminum angle to match and used it as a template as I spread the longeron.

In order to accomplish the spreading without pounding the apex with a heavy hammer (as called out in the build manual), I decided to squeeze the angle against a large socket in a 5-inch vice.  This worked well using a 16-inch pipe as a cheater on the vice handle.  I tried using a longer piece of  3/4-inch pipe (the width of the vice jaws) as a spreader rather than the socket, but this required more force than I could muster, even with the cheater.  For the second longeron, I compromised using a longer, larger diameter deep socket as a spreader.  This was the best of the three.  After reading other blogs, I discovered that others used a version of this method.

After spreading the angle 5.4 degrees, the build manual calls for the top surface to be twisted back 2.7 degrees so that it's once again horizontal.  According to the manual, this is to be accomplished using a "metric crescent wrench."  After a long search and at great expense, I was able to acquire one of these from a mail-order outfit in Russia. ;-)  Since I'm finished twisting longerons, I'll part with it for half price.  Oregonian humor.

The bending of the longeron was accomplished using the aforementioned dies from Larry Buller (shown just to the right of the small vice in the picture).  These worked well for the bend, but I had incorrectly thought that using the dies would limit the out-of-plane bend which results from the pound-with-a-heavy-hammer method described in the manual.  This didn't happen.  I started out bending the amount required to fit the template, then rotating the angle 90 degrees in the vice and removing the unwanted bend by hand (the dies can only bend in one direction).  This reduced the original bend, so it was an iterative process: bend, rotate, bend, rotate, etc.  On the second longeron I wised up and made the bend in the desired direction a few degrees more than needed to fit the template, resulting in less unwanted out-of-plane bend to remove.  This whole process did not leave me with a warm, fuzzy feeling like some of the procedures do.

***Update*** (1-22-13)
If I had to do this again, I'd use the "Orndorff Method" where the two longerons are clamped together in a T and bent at the same time.  This prevents out-of-plane bending and apparently works well.  Search on it.