Monday, May 26, 2008

The Nose Cone

While the nose cone appears to be completely assembled this is not the case.  The seams/gaps formed by the two-part mold cavity are pronounced and must be filled for aesthetic and strength reasons.  I propped up the nose cone on my sander for support and, using a spirit level, I ensured that the seam was horizontal.  I then mixed up a batch of epoxy and filled it with some colloidal silica.  I applied this gel to the length of the seam verifying that the gap was filled and that I'd left a ridge so I can later sand it flat forming a smooth cone.  It's a bit difficult to see but this is the best I could do with garage lighting and a flash:

Next I had to add 70 ounces (~4.5 pounds!) of lead to the inner tip of cone to ensure stability with the heaviest motor.  I weighed out the lead shot into two 35 oz batches, mixed up two cups of epoxy ~1/3 full each, combined the two batches, and poured them into the inverted nose cone:

Finally I drilled and mounted a U-bolt into the final bulkhead and sanded it to fit inside the uneven shoulder of the nose cone:

Again the fixing of this bulkhead is on hold until the expanding foam arrives.  I plan to fill the nose cone with foam to improve its rigidity and resilience.  It seems fragile and likely to crack/break upon ground impact without inner foam.

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