Blast shields
The Thrifty Rocketeer blog continues...
Last entry, I mused about assembling a simple set of launch pad gear, complete with a launch rod, launch pad wires, and alligator clips to attach to a battery.
I also lamented not having settled on a good, simple blast shield for my launch rods yet. I asked for some suggestions.
Well, an experienced rocketeer responded with a simple suggestion. And I immediately took to it...I think. What he suggested was a Terra Cota plant pot.
I think I have heard of this before, as a poor man's way to set up a simple launch pad that won't burn. When up-ended, the pot would act as an anchor and a blast shield. The launch rod can be slipped down through the large hole and into the earth. At least, that's what I envisioned.
But I've already built a couple PVC launch pads, and bought a few launch rods in preparation. Since I've already got the pads set, I just need the shield. And that's why I did it.
I went to Lowe's and looked at their Terra cota clay pots...and found they have various sizes of drip plates that go underneath to hold water and overflow. I quickly priced a few at a buck or so each and bought them.
I took them home (along with a single steel electrical box plate) and drilled them all with a 1/8" hole to thread a small rod through. My wife was dismayed to see me ruin a clay pot plate, as it would now leak, but I hid them in my rocketry gear, figuring she'd never get to them again. (Little do you know how crafty she is.)
But the point is I am now set with my shields, and ready to go launch.
All I have to do is wait for the NAR official sanction of our launches to return. That is, the ban must be lifted. And I'll be good to go.
Who knows, maybe I'll wander down to the abandoned golf driving range and try my gear out this weekend.
----------- I'm a little bit nervous about the extension cords running out to the pad. I have designed the leads and the clamps to be powered from my car battery. I hope 12 volts DC will not have an adverse effect on the launch, and vise versa... that a dead short won't injure my car battery. But I know the igniter will burn through quickly, and the short will be open very quickly.
The only short cut I have taken, is the lack of a control switch or launch control box for momentary contact.
My plan is to connect everything up, but stop at the power plug end of the battery clamps. By holding the two ends of the power cords in my hands, I can deftly connect and immediately disconnect the plugs, pulling them apart the moment the engine ignites (or doesn't)... to reduce any possibility of damage.
In theory, this will accomplish the launch, but at minimal expense and risk. At least, I'm willing to try this, if I am alone and not in a club launch setting.
I'll let you know how it goes.
Until then, keep your glue capped, save your balsa scraps, and keep the power leads unplugged until the last moment. You have been warned!
Last entry, I mused about assembling a simple set of launch pad gear, complete with a launch rod, launch pad wires, and alligator clips to attach to a battery.
I also lamented not having settled on a good, simple blast shield for my launch rods yet. I asked for some suggestions.
Well, an experienced rocketeer responded with a simple suggestion. And I immediately took to it...I think. What he suggested was a Terra Cota plant pot.
I think I have heard of this before, as a poor man's way to set up a simple launch pad that won't burn. When up-ended, the pot would act as an anchor and a blast shield. The launch rod can be slipped down through the large hole and into the earth. At least, that's what I envisioned.
But I've already built a couple PVC launch pads, and bought a few launch rods in preparation. Since I've already got the pads set, I just need the shield. And that's why I did it.
I went to Lowe's and looked at their Terra cota clay pots...and found they have various sizes of drip plates that go underneath to hold water and overflow. I quickly priced a few at a buck or so each and bought them.
I took them home (along with a single steel electrical box plate) and drilled them all with a 1/8" hole to thread a small rod through. My wife was dismayed to see me ruin a clay pot plate, as it would now leak, but I hid them in my rocketry gear, figuring she'd never get to them again. (Little do you know how crafty she is.)
But the point is I am now set with my shields, and ready to go launch.
All I have to do is wait for the NAR official sanction of our launches to return. That is, the ban must be lifted. And I'll be good to go.
Who knows, maybe I'll wander down to the abandoned golf driving range and try my gear out this weekend.
----------- I'm a little bit nervous about the extension cords running out to the pad. I have designed the leads and the clamps to be powered from my car battery. I hope 12 volts DC will not have an adverse effect on the launch, and vise versa... that a dead short won't injure my car battery. But I know the igniter will burn through quickly, and the short will be open very quickly.
The only short cut I have taken, is the lack of a control switch or launch control box for momentary contact.
My plan is to connect everything up, but stop at the power plug end of the battery clamps. By holding the two ends of the power cords in my hands, I can deftly connect and immediately disconnect the plugs, pulling them apart the moment the engine ignites (or doesn't)... to reduce any possibility of damage.
In theory, this will accomplish the launch, but at minimal expense and risk. At least, I'm willing to try this, if I am alone and not in a club launch setting.
I'll let you know how it goes.
Until then, keep your glue capped, save your balsa scraps, and keep the power leads unplugged until the last moment. You have been warned!
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