5 wires emanate from the trim tab motor, and need to be stripped, crimped into male micro-fit Molex pins, and then inserted into the black Molex housing shown below. Easy enough task? Not without the right tools. First, I ordered a crimper that another blogger recommended - it is cheap, and really not great quality; however, for these 5 crimps, it should (and did) work fine. Then I tried to strip the 5 wires with my trusty old (emphasis on OLD - 35 years at least) wire strippers that my dad passed down to me. No dice - they were too dull to do the job on these fine 26AWG wires. Next, I ordered a Chinese knock-off automatic wire stripper ... which is STILL in the mail, on the slow-boat from China. Since I wanted to complete the elevators this week, I ordered a very high quality wire stripper (Ideal Stripmaster; 16-26AWG) that came the next day, and made quick work of stripping those 5 wires. That's it - no more crappy tools!
A word about micro-fit Molex connectors: Several folks on the VAF forums have made a big deal out of these connectors, but they are actually quite easy (if your eyesight is good - they are tiny). Strip about 1/8" of the wire; insert the metal pin into the crimper, making sure that the back end is flush with the crimper; insert the wire such that only about 1/16" of the insulation sticks into the pin - i.e. just enough so the first band crimps the insulation and the second band crimps the wire; and, then crimp firmly (but not too hard); finally, tug the wire to make sure the connection is secure. Next, note that the pin's cross-section is a "U" and also note that inside each hole of the 6-pin molex housing has a little tab on one side. That tab slides between the "U" of the metal pin. You may or may not hear a click when it fully inserts; pull to make sure the pin seated in the black housing, and that's it! It only goes in one way. Others have just tried rotating it 90deg when it doesn't work ... but why guess? Take a look inside the housing to locate the little tabs, and then orient your pins to match.
Motor housing wires attached to the SteinAir harness:
Trim tab motor installed, with pushrod mounted to trim tab horn. You can test the motor by connecting a 9V battery to the two white wires (not the other three), reversing polarity will make the trim tab move in the opposite direction. Lots of satisfaction with this - I assembled a part that moves. Huzzah.
The other side, prior to rolling the leading edge:
Rolled left leading edge, taking care not to damage the trim tab motor harness. After doing the rudder and right elevator leading edges, I think I have a nice system ... I just hope the clearances work out when the parts are fitted.
leading edge riveted:
Close-up:
Micro-fit molex connector, taped out of the way:
I think I found a new less-favorite activity - working with lead. The 4 counterbalance lead weights have to be trimmed top and bottom to fit the rib angles, and then the inside weight has to be shaved to fit within the rib flange depth. 2.5 hrs later, and they were shaved enough to install. Here is the left inside counterweight:
Left outside:
Right inside:
Right outside:
After 70.5hrs, the elevators are finally complete. The fuselage is next ... onward and upward ...
2 comments:
Alex, you mentioned that you had a system for rolling the leading edges of the elevators. Which system did you use? Thanks
Hi Jeff - I used 1" PVC pipe (nothing special; it was from Lowe's or HD), and taped the tube to one side of the leading edge using duct tape. The duct tape was placed half on the skin along the entire length. I carefully wrapped the other half around the PVC pipe. Then, I used vise-grips to "roll" the PVC pipe (and thus the leading edge skin), slowly, while massaging it a little. I preferred rolling rolling upwards, since I could get better leverage that way. I'd roll the first edge almost all the way to the final position, then switch and roll the other side. Once both were touching, I finished by just using my hands, carefully, taking my time to roll and flatten. Each leading edge took at least 1.5 hrs to get to the final shape. You don't want a crease at the spar, nor do you want any tension when you are clecoing the ends together, prior to blind-riveting. Hope this helps - let me know if you have any questions.
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