Thursday, April 20, 2017
Odd'l Rockets Goony G-16 Build, Part 3, Engine Mount - TIP
TIP: The next time you are at a framing store, ask if they have any scrap mat material. It's perfect for centering rings or fiber fins. It's thicker than the centering ring material you'd find in a kit. You should be able to buy some very cheap.
I'm tracing around the BT-60 main body tube with a mechanical pencil.
Center a BT-20 on the circle you just drew. It isn't easy to get it perfectly centered and may take a few tries. Trace around the BT-20 engine mount tube.
Cut out the center first, right on the pencil line.
(Inset picture) You can cut the outside ring with scissors, cut just inside the pencil line.
You can use some 220 grit wrapped around a finger to slightly widen the inside hole until the BT-20 slides in.
(Left picture) Stack the two rings on the BT-20, sand and round the outside until it slip fits into the BT-60.
Here's the rings before and after using the rotary punch.
This rocket will have the replaceable Kevlar line, that's the small hole at the bottom of the rings.
Notice the faint pencil lines near the center of the ring. Always mark before making any punches.
Here's the finished mount with the Kevlar line running through the Q-tip tube.
The Kevlar and tied on elastic are rolled up and inside the engine tube for gluing into the main airframe tube.