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Old 02-25-2006, 08:19 PM
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CPMcGraw CPMcGraw is offline
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,357
Exclamation Modified Plan -- Aerobee 150 Standard with booster

The Aerobee 150 was originally a two-stage vehicle, using a solid booster and a liquid sustainer. Most model configurations, including the MMI/EIRP version, the Estes "Sparrowbee" (AKA Aerobee 300), the new SEMROC version, and all four of the BARCLONE editions, have either been flown, kitted, or drawn as a single-stage model. The Aerobee booster is a bit odd in size compared to the sustainer. It is smaller in diameter, and when viewed in side profile this difference is noticeable. Finding an appropriate booster body tube to match up to the sustainer, without having a grossly obvious distortion of scale, has been a challenge no matter what size of model is built.

Also, the transition at the top of the booster is a difficult build as it is a simple tubular structure with an open-air gap between the nozzle of the sustainer and the top of the booster body. The prototype Aerobee ignited the sustainer 0.3 seconds after booster ignition, so there was a measure of thrust blasting down on the top of the booster for 2.2 seconds before separation.

The BARCLONE version of the booster simplifies the transition to a cardstock shroud, which can be printed with a tubular frame image. A 4.125" length of ST-7 tubing runs from the rear edge of the sustainer motor tube through a 3" length of BT-40 tube, and couples onto the sustainer motor tube with a SEMROC HTC-7B (outside) coupler. This is hidden behind the tapered shroud. Any loose fit between the ST-7 and the BT-40 can be filled with a couple of 0.25" wide strips of self-adhesive label stock wrapped around the ST-7. The fins are the same size as the sustainer, but with non-rounded corners, and these hang behind the rear edge of the booster tube 0.5". One change that has to be made to all three Aerobee 150 designs is the elimination of the motor hook from the engine mount, as this would interfere with the coupler. Both motors are friction-fit.

New design data for the Aerobee 150 Standard:

Overall Length: 21.11"
Sustainer Diameter: 0.908"
Booster Diameter: 0.825"
Stack Weight: 1.34 oz

B6-0/A8-5......760'......6 FPS
B6-0/B6-6.....1030'.....13 FPS
C6-0/A8-5.....1200'.....19 FPS
C6-0/B6-6.....1440'......9 FPS
C6-0/C6-7.....1960'.....25 FPS

All stack configurations achieve safe flight V in 30" or less. The booster shown in this RKT file should mate to the other two A150 versions with similar performance numbers.

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File Type: rkt Aerobee 150 Standard with booster.rkt (88.2 KB, 104 views)
Craig McGraw

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