| Midget
2.6 |
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| BT-80 Upscale Midget with 3x24mm cluster | |||
Midget Family | Thridgets |
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Here's the full
stack. It
flies on three 24mm C11-0 or D12-0 boosters staged to three 24mm
sustainers - C11's, D12's or E9's. With D's to E's, that amounts
to F impulse staged to G. Each booster fin breaks away separately from the others to ensure that its corresponding sustainer has the best chance of lighting. The paint is RustOleum premium. The orange is a new addition to their premium line, and it came out great. Chrome MonoMote was applied to both sides of one fin to improve visibility. |
| The BT-80 (2.6")
airframe tapers
to a BT-70 (2.2") tailcone which accomodates interchangeable motor
mounts. 2-56 all-thread runs the length of the opening and is
used to retain the mount. It is anchored in a birch plywood
bulkhead. |
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The top nut holds the
motor mount in while the center one retains the motors, but only in
single-stage configuration. When staged, the center retention is
omitted, and the motors are friction fit. |
| For single stage flying, in addition to the 3-motor cluster, single 24mm and 29mm mounts have been fabricated along with a cluster mount with four 13mm tubes and three 18mm tubes. |
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| Other options under consideration include these two cluster combinations. |  |
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The chrome MonoKote
shows up well in this pic. |
| A kevlar shock cord
is anchored to the motor mount bulkhead. To guard against
zippers, it transitions to a 1" nylon ribbon through the opening, then
back to kevlar to the nosecone. The nylon is folded then sewn. |
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The nosecone is from
a Fat Boy. Its base was cut open and a plywood disk was epoxied
into the forward end. The disk includes a T-nut for attaching a
screweye and noseweight. The hollow nosecone provides extra space
for the shock cord should it be necessary. |
| Here's a launch pic from the Extreme BP event November 18-19, 2006 in Windom, Texas. |
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|
December 22, 2008 |
