Sunday, July 11, 2010

SR-71 plastic model conversion

I've finally got some decent work done on the SR-71 conversion. It started out a non-flying 1:48 plastic model weighing 11.1 ounces. It took up a lot of space and didn't do anything interesting. Not acceptable.

So, clearly, the thing to do is to stick a rocket motor in it. 18mm just wasn't going to cut it - with any noseweight, it'd be underpowered even on D24Ts. So, 24mm it was.

First, I did some surgery. I cut off the tailcone to accept a 24mm diameter internal tube. I removed the landing gear doors, cut out some internal bulkheads that obstructed the tube, and replaced the doors. I cut off the body just forward of the wings, and the 2" tip of the nosecone.

I took a 15" length of 24mm tube and put it through the main body, with 1" sticking out the aft end for motor retention purposes, and 3" out the front to couple with the nose section. I glued a shock cord and a bunch of BBs into the very tip of the nose cone, then reglued the tip to the main nose cone. I glued two dowels inside the nose section to keep it in place when it's attached to the body section.

(It makes a lot more sense when you're doing it, rather than reading it. Sorry.)

Then, I glued the shock cord to the sticking-out section of the internal tube. Finally, I took black paint and painted over all the exposed sections of white tubing, broken plastic, etc.

It looks pretty nice, and it should fly nicely on high-thrust E and F motors. First flight will probably be on an F35W

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