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Saturday, August 18, 2018

New Odd'l Rockets Heavy Wall BT-20H Tubes Available!

Over the years, I've grown to hate BT-20 body tubes. The first time I tried to remove a friction fit engine from an Estes Beta, the tube was bent and the rocket unusable.

Now available from JonRocket.com:
BT-20H HEAVY WALL BODY TUBES!
To see the listing, CLICK HERE


On the left is a standard BT-20, on the right is the heavy wll BT-20H.
Standard Estes BT-20 style tubing is thin walled (.013") and prone to buckling and bends. Thin wall tubes can’t insulate well against the heat of ejection charges. Paint above the engine mount area can blister.
Heavy wall BT-50 tubes are already available, why not a stronger BT-20?

This new tubing has the same wall thickness (.021") as a BT-55 or BT-60 tube.
The inside diameter is the same as a BT-20 tube. (.710")
Thicker wall tubing is less likely to shrink or “coke bottle” when a glue fillet dries.
Standard engine blocks (5/20 rings) will fit as an engine block.
Existing centering rings can be easily peeled or sanded to fit the slightly wider outside diameter.
Comparing both tubes, an 18" length of the heavy wall BT-20H weighs a little over 1/10th an ounce more than the standard BT-20.

Applications:
  • Engine mounts - Perfect for the new C and D Quest Q-Jet engines.
  • Ejection Stuffer Tubes - Stronger when exposed to ejection charges. Longer life, more flights.
  • Strap-On Boosters - Less damage on landing under streamer recovery.
  • NAR Superroc Competition - Stronger tubes for longer length designs.
  • Sport Models - Stronger as a main air frame tube. More success for school, Scout, 4H and general sport rocket projects.
The yellow plastic nose cones from Apogee are a great fit for the thicker wall tubes. These nose cones have a wider shoulder than standard BT-20 fit nose cones. CLICK HERE

6 comments:

  1. The thicker walls should also help mitigate zippering, though precautions should still be taken. Looks like centering rings for the st-7 tube will work, as well as bc-7 nose cones with their thicker lip. Good call, since st-7 tubes are not widely available now.

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    Replies
    1. Hi BAR,
      It's really easy to sand the inside hole of a flat centering ring to fit the BT-20H. I decided to go with the BT-20 inside diameter so you could use the BT-20 sized engine blocks. Engine fit in ST-7 tubes was always loose and would normally get few additional wraps of tape.
      I showed these to Lee Piester at NARAM 60. He thought they were a good compromise between an ST-7 and a BT-20.

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  2. That's going to be great for those long skinny clones like the Astron Andromeda - help prevent them from crimping.

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    Replies
    1. Hi Scott,
      Years back I launched an Andromeda with a C6 engine. It buckled in two places forming a triangle and pinwheeled over the field!

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