Tuesday, May 29, 2018

Apogee Payload Altitude Rocket Build, Part 8, Pop Launch Lug




The doubled tip of the top wire is bent to allow an easy insertion and removal in the hole in the body tube.

I'll be using the altimeter vent holes already in the upper payload tube.
This is the bent wire that friction "clips" behind two facing fins.
The initial bend is adjusted to fit each individual model and fin shape.

Both the top and bottom wires are either taped or attached with glued card stock to the top and bottom of the long launch lug.

For an easier fit of the top wire, the hole was formed so the upper end of the hole is pushed out a bit. The low end of the hole is pushed in at the same time. I used a small rat tail file to press and form the hole, I didn't file or removed any body tube wall thickness.
On the left is the pop lug beside the body and ready to place on the model.

On the right - The upper bend is slid in one of the altimeter holes.
The sides of the lower wide bend are set behind two facing fins.

The pop lug will stay on the rocket long enough for it to get up to stable speed. At the top of the launch rod the tape wraps stop the lug, leaving it on the rod. The rocket continues up without the drag of the launch lug.

HISTORY: As far as I know, the Pop Lug was designed by Col. Howard Kuhn of Competition Model Rockets or C.M.R. He came up with many rocketry innovations including the smart, simple Kuhn Tube Cutter. C.M.R. was the first to manufacture lightweight vacu-form nose cones and egg capsules.

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