Bruiser
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Some of you might have been following my thread on rockets built using BT-20 body tubes and 13mm motors. If you haven't seen that thread it's right here: https://www.rocketryforum.com/threads/mini-engine-rockets.179096/
Well I have started my first build and it's Black Brant Vc. It'll be a nice addition to my Rocketarium Black Brant V and my own 29mm design 2.5 inch Black Brant VC.
I started with the motor mount and it is just a 2" long piece of BT-5 tube. I show it marked for the centering rings
The Black Brant has a step down in the fin can area so I used an 18mm engine block insertion tool to simulate that. I had to peel a few layers of paper off the outside of the centering rings so they would slide into the tube. I glued it in so the aft edge of the aft centering ring was even with the aft end of the yellow tube. The yellow tube will be inserted into the aft of the main body tube 1 inch.
The yellow tube fits a little loose inside of the BT-20 so I applied a little more glue than normal. I inserted the yellow tube in one inch and used a piece of angle aluminum and a spare piece of body tube to insure it was all aligned correctly.
You can take the boy away from mid-power but you can't take away the CWF
And after sanding
Now it was time to move onto the fins. Could have made them from 1/16th or 3/32 balsa or bass but that would be too simple. Mine were made from 2 pieces of 1/32nd balsa with a 1/64th ply core. Then I sanded the taper going outboard, followed by the tapers on the leading and trailing edges. Then I made up a fin pattern for Avery label paper and printed out some fin skins. I creased each line and applied them to the fins. I trimmed/sanded the paper around the edges then sealed the edges with thin CA. Some fun facts: each fin was .03 ounces before sanding, .02 ounces after sanding and back to .03 ounces after papering
Next up was to attach the fins so I drew some lines on the body tube. I used the method of white glue applied to the root which was then touched to the body tube. lifted away for a brief moment before being set in place permanently. First time I have done this and it was kind of amazing how quickly it grabbed. Of course I had to put the nose cone on and take a pic after the tree fins were glued on
That's it for now. Next week I will pick back up starting with glue fillets and the scale fin plates.
-Bob
Well I have started my first build and it's Black Brant Vc. It'll be a nice addition to my Rocketarium Black Brant V and my own 29mm design 2.5 inch Black Brant VC.
I started with the motor mount and it is just a 2" long piece of BT-5 tube. I show it marked for the centering rings

The Black Brant has a step down in the fin can area so I used an 18mm engine block insertion tool to simulate that. I had to peel a few layers of paper off the outside of the centering rings so they would slide into the tube. I glued it in so the aft edge of the aft centering ring was even with the aft end of the yellow tube. The yellow tube will be inserted into the aft of the main body tube 1 inch.

The yellow tube fits a little loose inside of the BT-20 so I applied a little more glue than normal. I inserted the yellow tube in one inch and used a piece of angle aluminum and a spare piece of body tube to insure it was all aligned correctly.

You can take the boy away from mid-power but you can't take away the CWF

And after sanding

Now it was time to move onto the fins. Could have made them from 1/16th or 3/32 balsa or bass but that would be too simple. Mine were made from 2 pieces of 1/32nd balsa with a 1/64th ply core. Then I sanded the taper going outboard, followed by the tapers on the leading and trailing edges. Then I made up a fin pattern for Avery label paper and printed out some fin skins. I creased each line and applied them to the fins. I trimmed/sanded the paper around the edges then sealed the edges with thin CA. Some fun facts: each fin was .03 ounces before sanding, .02 ounces after sanding and back to .03 ounces after papering

Next up was to attach the fins so I drew some lines on the body tube. I used the method of white glue applied to the root which was then touched to the body tube. lifted away for a brief moment before being set in place permanently. First time I have done this and it was kind of amazing how quickly it grabbed. Of course I had to put the nose cone on and take a pic after the tree fins were glued on

That's it for now. Next week I will pick back up starting with glue fillets and the scale fin plates.
-Bob