Natomas Follies

VSB - very slow build

Thursday, February 7, 2013

Finished with empennage (for now)

I sent in the order form and check to Van's Aircraft for the wing and lighting kits, which ups the cost tally to ten grand.  As they say, in for a pence, in for a pound.  I can understand why the wing kit costs so much ($5,700) with the main spars and all, but I'm not sure why the optional lighting kit is $1,350 and wonder if the word "optional" has anything to do with it.  I guess I'll find out.  Since their web site says it takes eight weeks to fill and ship a wing kit order, I probably should have sent the order sooner.  Now I'm fresh out of things to work on.  The delay was because I'm relying on tax refunds to pay for it, and it took a while to convince the worried CFO that I would get our tax returns done early this year instead of waiting 'til the last minute as usual.  Her skepticism isn't misplaced doing taxes is my 973rd favorite thing to do, right after "get root canal" and "bang head on brick wall".  It takes hours to go through the TurboTax interviews that end up being a waste of time because the total expenses don't exceed some percent AGI limitation.  Then when it's done I always feel like there's some additional expense I should've listed on Schedule A or E or whatever, and that everyone else is interpreting what's deductible and what's not more liberally than I am.  IMHO the tax system shouldn't force 30 million otherwise honest long-form taxpayers to confront these ethical dilemmas.  Or hold on to so doggone many friggin' receipts.  Unlike Congress, not everyone can afford an accountant, so make it simple.  Stop using the IRS as an instrument for social change and get rid of all deductions, credits, loopholes, and incentives.  And lower the tax rates to compensate.  JFK lowered the tax rates in 1964 and Reagan did it in 1984 and both times tax revenue doubled within a couple of years and achieved better tax compliance.

Enough ranting about government and taxes.  There were a couple things left to do on the empennage that didn't require assembling the tailcone, stabilator, v-stab, and rudder.  Build plans pages 11-6, -7 & -8 has us make the aft servo tray and AST pushrod assembly.  Those parts connect the trim servo to the trim tab.  For those who don't know, a servo is a small electric motor that moves a connecting rod forwards and backwards. The trim tab is a control surface that pushes against the slipstream in flight.  Trim is used so the pilot can fly hands off instead of always pulling back on the control stick (to climb) or pushing forward (not climb).   It's also used by the autopilot to adjust airplane pitch attitude.

The hardest part was crimping Micro-fit pins onto the wires coming out of the the servo motor.  The 26 gauge wires are small and the pins are too.  Seriously.  Check out the picture.  The flanges on the pins are only a couple millimeters wide.  You need good eyes, a magnifying glass, and the skill of a surgeon to crimp the Micro-fit pin onto each wire using a special crimping tool that costs $324 bucks.  Fortunately Fry's has one that's used for crimping 30-gauge d-sub pins similar to Micro-fit pins that's nearly as good and only costs $17.  It was a tough decision but I chose that one instead.


Not being particularly gifted in manual dexterity the crimps were less than perfect, but they're tight, they conduct electricity, and the pins won't slip off the wires (or vice-versa).  I hope.  Once the pins are crimped onto the wires they're inserted and locked into a mini-Molex plug that will plug into the wiring harness.  Assembling the rest of the pushrod assembly was fairly easy, if a bit time-consuming.  Here's a picture of the finished pushrod assembly with the servo:

 At this point the push rod assembly is supposed to be fitted onto the tailcone bulkhead and trim tab and adjusted.  Since I'm not bolting those things together at this time the pushrod goes back into the drawer.  It won't be installed until after the wings and fuselage are done.  Couple of years maybe.  This is a VSB, remember?   And that wraps up everything I can do in Section 11.
Moving on to Section 12, Vans has us trim the bottom and rear of a fiberglass vertical stabilizer tip.  Mister B's belt sander was especially well suited for that.  The bottom of the v-stab tip is flat, and the belt sander is flat, so trimming was easy, if somewhat smelly.  This was definitely a breezy-day outdoor job.  You don't need fiberglass dust in your work area.
Once trimmed I test fit the tip on the v-stab and sanded a little more for a perfect fit.  Pretty easy with the belt sander.  Then I wrapped sandpaper around a paint spray can to trim the curve at the back indicated by a scribe line.  Once the fit is perfect rivet holes are match-drilled, cleco'd, and the tips are riveted on.  I'll probably do a little more fit sanding with the rudder on to get 1/8" clearance between the v-stab tip and the rudder tip through the full range of rudder travel.  It shouldn't take long.

It was the same procedure for the rudder tip.  This time, instead of doing it on the driveway, I set up a work table.  Much better for my achy back.

For the rudder tip it was a much tighter fit onto the rudder and at first it didn't want to go in.  By sanding an angled bevel on the bottom of the tip I was able to to fit it on.

With the tips now riveted on, the v-stab and rudder were moved back to an out-of-the-way corner in the family room.  And that's all I can do for now until the wing kit gets here in six or seven weeks.

Time to work on taxes.