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!

Comments

Post a Comment

Popular posts from this blog

The End of the Line

Image
 The Thrifty Rocketeer blog continues... Well, for years, the state of the model rocket industry relied upon plans and patterns that were photocopied or printed out, and then applied to standard sheets of balsa to be cut out. Eventually, the various parts for various sized rockets were packaged in groups or blister packs, and sold at hobby shops across the nation.  The emphasis was on home brew or building a rocket to specifications and plans. Eventually, entire kits were pre-packaged, with all the parts that one would need.  And then, laser cut shapes, fins or parts were already pre-cut, doing away with the need for most of the patterns and tracing. So what happened to all those bags and bister packs of parts of rockets?  That is, a baggie of various nose cones... or connectors... or transitions or more ?   Many of  those packages remain at your local mom and pop hobby store, just waiting for someone to come in and buy some of their pegboard stock....
Read more

sleeping with the enemy

Image
 The Thrifty Rocketeer blog continues... First thing I did when they put in a Hobby Lobby in my smaller metropolitan town, 40 miles away, was to grab an application to work there.  Now I know what you're thinking... "How could you?  Who would want to work for that conservative corporation?".. as my daughter would say.  And you'd be partially right. I saved the application and took note of the mailing address. Within the first month or so, most of the initial buying frenzy was over, having sold out of some things, but not everything.   But it seemed nothing new was getting restocked. So, I got on my word processor and wrote a letter to the store management, THANKING them for bringing the store to our isolated metro area. I pointed out that many of the items had sold through completely, and how much we had appreciated their stocking rockets. Then I also encouraged them to restock and consider expanding the display, pointing to the fact that as rocketeers grow...
Read more

Death of a Hobby

Image
 The Thrifty Rocketeer blog continues... No, this is not a column about how Model Rocketry is a dying hobby.  It's actually about another sister hobby that sometimes overlaps into Rocketry. I'm talking about Amateur Radio. Just this last weekend, our local Ham Radio club held a "swap meet" which is commonly called a Hamfest.  These gatherings to buy and sell used equipment, parts and visit old friends typically happen just once a year and in the absence of the late Radio Shack, is one of the only places to find parts and electronic elements. There is also testing held to advance to higher licenses. The admission varies depending on the club, their overhead, expense of renting the hall or venue, and the number of tables that they can sell to area vendors who will drive across state with their wares to set up for the half day show. It's not uncommon for amateur radio operators to drive across state to attend, pay admission and get a single entry into the door prize ...
Read more