James Duffy
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Time to turn our attention to the WAC sustainer at the pointy end of the rocket. Let's start by taking a look at the example built for the first Bumper WAC model documented at the start of this thread three years ago.
The WAC is a pretty simple prototype, and so was the model we built back then. The airframe tube is plain-old BT-20, and the nose cone was a plastic Estes cone sourced from a spare parts box (an Estes PNC-20A, perhaps?). The cone was lacking in a couple of ways. First, it was too short, and to mimic the scale cone length I extended the gray color onto to body tube below to fool the eye. Second, the ogive WAC cone used on both B-7 and B-8 terminated in a short point, not the blunt tip found on the Estes cone.
The spin motor was a particularly half-assed representation, spurred on by limited time and laziness. Rather that fashioning the complex tetrahedral shape of the prototype, I just cut out a diamond shape and stuck in in place. That won't do for the new model.
I reached out to my good friend Mike Nowak, who operates (along with his son Nick) a small firm called Galactic Manufacturing. Mike has developed some pretty extensive 3d modeling skills over the past few years for his magnificent Saturn V models, and Nick has become a virtuoso laser cutter artist. I whipped up a simple drawing of the parts needed, and sent that to Mike along with some photos of the WAC details. We went through a few virtual iterations of the parts until we had exactly the right vibe. Mike then printed the parts on his spiffy new printer, which uses some sort of unspeakable voodoo to produce parts without the nasty stratified lines that make so many printed parts unacceptable for scale models. Here are the results:
Finally, a hand-laid fiberglass airframe tube will be used instead of a paper tube. This was created early last year and is documented in post #143.
The fins on the original were lasercut from 1/16"-thick basswood and are attached to the airframe via TTW tabs which integrate with a 13mm motor mount. Unfortunately, the maker space where I had access to a laser cutter imploded in a nasty bankruptcy a couple of years ago. In a rare case of technological regression on this model, the new fins will be cut by hand, in the manner of a cave-dwelling savage.
More later,
James
The WAC is a pretty simple prototype, and so was the model we built back then. The airframe tube is plain-old BT-20, and the nose cone was a plastic Estes cone sourced from a spare parts box (an Estes PNC-20A, perhaps?). The cone was lacking in a couple of ways. First, it was too short, and to mimic the scale cone length I extended the gray color onto to body tube below to fool the eye. Second, the ogive WAC cone used on both B-7 and B-8 terminated in a short point, not the blunt tip found on the Estes cone.
The spin motor was a particularly half-assed representation, spurred on by limited time and laziness. Rather that fashioning the complex tetrahedral shape of the prototype, I just cut out a diamond shape and stuck in in place. That won't do for the new model.
I reached out to my good friend Mike Nowak, who operates (along with his son Nick) a small firm called Galactic Manufacturing. Mike has developed some pretty extensive 3d modeling skills over the past few years for his magnificent Saturn V models, and Nick has become a virtuoso laser cutter artist. I whipped up a simple drawing of the parts needed, and sent that to Mike along with some photos of the WAC details. We went through a few virtual iterations of the parts until we had exactly the right vibe. Mike then printed the parts on his spiffy new printer, which uses some sort of unspeakable voodoo to produce parts without the nasty stratified lines that make so many printed parts unacceptable for scale models. Here are the results:
Finally, a hand-laid fiberglass airframe tube will be used instead of a paper tube. This was created early last year and is documented in post #143.
The fins on the original were lasercut from 1/16"-thick basswood and are attached to the airframe via TTW tabs which integrate with a 13mm motor mount. Unfortunately, the maker space where I had access to a laser cutter imploded in a nasty bankruptcy a couple of years ago. In a rare case of technological regression on this model, the new fins will be cut by hand, in the manner of a cave-dwelling savage.
More later,
James