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This blog is for entertainment purposes only, and is not meant to teach you how to build anything. The author is not responsible for any accident, injury, or loss that occurs as a result of reading this blog. Read this blog at your own risk.

Sunday, July 13, 2014

Nose and nose gear - part 16

Forward nose structure (7.8 hrs)

The longer nose needed a support framework, and this is where some of the pieces Wade and I glassed last month came into play.


"Look at those biceps!"


After a few “dry runs” trying all kinds of devices to hold the little arms perpendicular to the bulkhead, I settle on two pieces I had made for the mill then discarded. These had exact 90˚ angles, good height, and small base to fit between the two arms I would be floxing.


Figuring things out before getting sticky


I mixed some West System flox because it cures hard enough to handle in just a few hours, and attached the small brackets.


West System flox


While the flox cured in the very hot shop, I spent some time cutting BID tapes out of BID scraps I had been collecting for some time.


Recycling


Then it was the usual sequence... flox fillet, BID tape, and peel-ply.


Flox fillet

BID tape

Peel-ply


The next morning I trimmed it, sanded it, and started to ponder how to proceed.


Forward nose structure

Who's gonna hold this thing?


After an hour of trying different things that didn’t work, and brainstorming with stray neighbors, I erected a small structure that, though flimsy, seemed to be able to keep things lined up in a repeatable fashion, and allowed me to check a few measurements using both hands.


For lack of a smarter solution...


Because I didn’t trust this structure to stay put for very long, I decided to use “5 minutes epoxy”. Although I had never used it before, the package said it would set hard in 5 minutes, and achieve full cure in 24 hours. The 5 minute part is what I was after.


5 minute epoxy


So, I mixed equal parts of the stuff, put a generous amount on rear end of the brackets, and carefully laid it back into my contraption to harden. I also took this opportunity to prepare more BID tape, and I applied a flox fillet to the joint, followed by the tape, and peel-ply.


Flox fillet

BID tape, and peel-ply.


At this point, I thought I was done for the day. That is until I shone a laser on the fuselage centerline markings, and noticed that the one on the small nose bulkhead was off by more than 1/4” (6.4 mm) to the right (airplane left)!!!

I think I went through all 5 stages of grief in rapid succession, denial, anger, bargaining, depression, and acceptance.

With the 5 minute epoxy hardening fast, my options were rapidly disappearing. I could always “go nuclear” later, and do a complete tear down so, I tried applying a measured amount of sideways traction to the structure first, until I achieved the right amount of deflection.

This turned out to be quite a bit of force due to the need to counteract the fast setting 5 minute epoxy, so much so in-fact that I had to brace the fuselage to prevent it from slipping.


Straightening things out


To ensure the angles would be locked in once and for all, I opted to apply the inner BID tape at this time as well.


More flox fillet action

All taped up


With all the centerline marks lined up, the overnight waiting game bagan.


Verifying all centerlines line up


Will the marks be still lined up in the morning? 

Will the nose structure remain straight after removing the elastic strap?

I am happy to report that the answer turned out to be a YES to both questions.


Cured and cleaned up


To complete the structure I added BID tape to the last joint.


Last joint to get the BID tape beauty treatment


While I was at it, I decided to add the F-6 bulkhead, and finish up the NG-30 box structure.


F-6 floxed to NG-30

F-6 glassed...

... and peel plied



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