THE AUTHOR
Which is more breathtaking - The BASSET MISSLE - the ROCKET TEAM VATSAAS logo T-Shirt - those marvelously sculpted calves - or perhaps that pincer-tight gluteus-maximus (shown here fully flexed for your viewing pleasure)?
DESIGN
I identified some LOC Precision components that were roughly double the dimensions of my first model. This determined that the upscale version would be 2X the original. I sketched out some rough dimensions on paper.
As my design began to take shape, I realized there were several formidable challenges ahead:
- 1. A way to do a computer simulation of a design with parallel body tubes.
- 2. The design of a mechanical decoupling mechanism for the boosters.
- 3. The design of an on-board ignition system.
- 4. A mechanical firing mechanism.
- 5. The design of the asymmetrical booster nose cones.
COMPUTER SIMULATION
Since stability and safety were both important concerns, I did not want to show up at a club launch without having simulated the flight on computer. I started noodling with RockSim to devise a way to at least emulate the proper silhouette. RockSim doesn't handle parallel airframes, so it proved to be a challenge. These are the workarounds I used in the simulation: Click here for RockSim 4.0 Basset File
BOOSTER COUPLER DESIGN
Shown here is the coupler design used on the Basset. The design used on the Thunderbird was both more reliable and more robust. click HERE to go directly to the Thunderbird Construction page for more details!
Both the Basset and the Thunderbird incorporated a design that would positively lock the boosters to the sustainer, and conversely, actively disconnect upon ejection. I designed locking mechanisms both forward and aft. The forward section detaches upon the firing of the ejection charge, disconnecting the pins in the coupler and deploying the recovery system. At the same instant, the ejection charge forces the aft section of the booster (containing the motor mount) backward about 1". This disconnects the pins in the coupler. When the coupler pins are fully withdrawn and the aft coupler assembly is fully extended, a 1/4" 'blowhole' drilled in the coupler tube is exposed, which vents ejection gases and sends them jetting toward the main airframe. This, combined with the ejection of the nose section, separates the booster from the sustainer quite effectively.
ON-BOARD IGNITION SYSTEM
The wiring diagram needed to be completed before I started gluing parts together. Perhaps the cleverest idea I had related to this item -- the wiring was integrated with the brass couplers. When the couplers are locked down, that part of the circuit is completed. Igniters are connected to the system by inserting them into IC bridge jumpers.
MECHANICAL FIRING MECHANISM
This was a simple solution. I mounted a mini phono jack in the main motor mount. The circuit is open when a plug is inserted and closed when the plug is removed. The plug is tethered to the launcher, and is pulled out when it leaves the pad.
|
ASYMMETRICAL NOSE CONESI never did make the asymmetrical nose cones for the Basset. I cut the tube at a 45 angle and traced an oblong bulkhead out of 1/16" birch plywood and epoxied it on. This was much maligned by everyone who knew better. I retired the Basset before I ever fixed this shortcut. I made outstanding booster cones for the Thunderbird, though. I'm extremely proud of those.
|
Click [HERE!] to go to the Thunderbird Design page.
|
Click HERE for video of the Basset flying on a central H123 and four D12's. The air starts are really late, so it is difficult to see them on this video. Sorry. And it would have been steadier if Rick had actually been looking through the view finder. It's also hard to count all the parachutes at the end of the .mpeg, but there are six of them.