L2 Photon Disruptor at NSL

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High Desert Rocketeer
Jan 20, 2009
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This will my 4 inch, 54mm Photon Disruptor.

Going for L2 at NSL 2017 in Alamogordo, NM. Received most of the Loc parts from Apogee. Got an Altimeter3 and Chute Release from Jolly Logic along with an Eggfinder Mini and Receiver from Eggtimer. Getting an Aerotech 1706 case with adapters from Wildman. Picking up a J motor from Chris' Rocket Supply at the event. Of course the graphics will be from Stickershock.

I am getting excited!
Today I got the upper 4in body tubes cut and the coupler made. Can't get the photo to upload from my phone, is there a trick I should know?
Try again with the TRF app...

Here is the initial. 4in tubes and coupler. Tubes we're cut to length with an xacto knife and a couple wraps of tape as a guide. Worked great, didn't take much longer than the Dremel and gave a much better edge! The coupler was made from an extra 2d length of BT. I tapered both longitudinal edges and used the last leftover BT as a glue guide.

Based on the upper tubes, the scale factor is 3.02. the NC is significantly shorter than the original, so some extra length of BT was added so that the overall length would be correct at 74in.


Got all the fins cut.

Small fins are made from 1/8" basswood cut on a band saw. Made the first from 1/4" birch plywood, but it looked disproportionately fat. The thinner version just looks better. And, they are low stress, no impact pieces that will be surface mounted.

The main fins and panels are 1/4" birch ply cut on the band saw and slotted at the router table. The will beounted TTW with generous amounts of epoxy.

The leading edge of all the fins are rounded, the trailing edges are beveled. A dangerous jig was used on the router table for the large fins. I won't do that again. LE's and TE's of the panels were rounded. The TE's should be less susceptible to damage this way. Corners of the panels were rounded using a glue cap as a template.



Filled the fin grains with some leftover drywall mud. Sanded with 220.


Applied large fillets on the motor tube joints. Used my gloved finger and alcohol to smooth the joint. Not so pretty, but strong.

Used popsicle sticks to smooth out the fin to panel. Uniform and attractive fillets. Mortise and tennon joins with epoxy and epoxy fillets should make for an impact resistant fin assembly.


Back to it after some time away.

Probably read on TRF taping alongside the spirals then filling the gap using a putty knife. Not sure who to credit, but seemed like a great idea. Overall, it was faster the the old finger tip and used a lot less drywall mud or CWF. Everything looked great till I pulled the tape off. The glassine layer came off with it. Left behind was two rough lines of bare cardboard each a tape width wide. I knew it could be fixed while primering, but expected it to be a hassle. I was pleasantly surprised when all the paper fuzz came off with the first sanding!

I will use the tape method again, but will try some quality low stick tape, not the cheap yellow stuff.




Left behind was two rough lines of bare cardboard each a tape width wide. I knew it could be fixed while primering, but expected it to be a hassle. I was pleasantly surprised when all the paper fuzz came off with the first sanding!

A technique you may find useful to seal in that fuzziness, if you're not going to wrap the LOC airframe in FG: I've used slightly diluted yellow wood glue to seal Loc tubing a few times. Rough up the glassine with sandpaper, then brush on Gorilla (or similar aliphatic resin), diluted with a little water applied with a brush. Allow to gently heat cure in the boiler/airing cupboard, then sand and repeat a couple of times. What you get is a harder surface that seems less prone to dings than just painted glassine. I also do a coat or two of the same dilution on the inside of the tube - it makes for an easier to clean surface after flights. Here's one I made a while back, just prior to primer.
back plate.jpg
Of course I am the one still finishing his rocket at the event!

Met two other rocket families just hanging out at the hotel. Good times already!

Great flight and recovery for L2 on Sunday!Thanks to Tom Kindig for the test, to Tom and NAR pres John Hochheimer for the observation, to Chris' Rockets and Aerotech for bits and advice, and to everyone there for the support!