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  • In a previous project we used sugar, stump remover, and a little bit of kitty litter,

  • to make “E45 equivalentrocket motors. In this project were adding time delays,

  • ejection charges, and sending a duct tape rocket, over 1,000 feet high.

  • I just made 10 rocket motors for under $5.00, and they only took about 10 minutes each.

  • Now to see if theyll even work at all, let’s strap one to a couple of bricks for

  • static testing, and light it up. When the propellent catches, you can see it’s actually

  • got an impressive amount of thrust. Now of course this

  • begs the obvious question. What would happen if we put one, in the paper rocket from a

  • previous project. So I just made a glorified version of the same thing, using cardboard

  • and duct tape. You can see the cardboard fins are just hot glued to the body, and I reinforced

  • the upper part of the tube with 3/4” PVC pipe to keep it rigid. The hole at the back

  • has just enough room to accept a single sugar motor, and you can see a little metal wire

  • holds it down in place. Ok, our rocket is loaded and ready to fly, but we still need

  • a way to launch it. I used the lid of a cooking pot, and a sawed-off marshmallow roasting

  • stick to make a simple blast pad. And the rocket’s just held on with pieces cut, from

  • the body tube of a pen. Alright, let’s light it off and see how it does. Now that’s not

  • too shabby for a rocket made from sugar and cardboard. From the time of apogee, it took

  • a little over 8 seconds to hit the ground, which means this thing shot up over 1,000

  • feet high. How cool is that? The problem, of course, is that there’s no parachute

  • on this thing, which means it’s going tolawn dart”, straight into the ground,

  • every time. That’s exactly why I’m out in the boonies, miles away from any people,

  • or property. Now it’s important to mention here that potassium nitrate is hygroscopic,

  • meaning when the propellent is exposed to air, itll slowly absorb moisture until

  • the fuel loses potency. This mix is about a month old, and won’t even light off anymore,

  • and you can see this rocket, doesn’t produce any thrust whatsoever. To reverse the hydration,

  • you could put it in the oven at 300F for 30 minutes. If youre willing to risk the possibility,

  • of an insurance claim. Ok, to make a parachute ejection charge, were going to need to

  • add a time delay function, and a little black powder. I just made this one out of acrylic

  • so you can see exactly whatll be happening inside the motor during the launch. You can

  • see that when the white mix ignites, it burns incredibly fast, then stops suddenly at the

  • black mark, where the delay mix begins. This amount of powder should give about a 5 second

  • delay, then ignite the ejection charge. .. Which youll see how to make in just a minute.

  • Now the recipe for delay mix is so incredibly simple. All we need to do is separate 20 grams

  • of the white mix, made in ourSugar Rocketproject, and add 15% baking soda by weight.

  • Which in this case brings the mix up to 23 grams total. Put the modified mix in a container

  • and shake it around for about a minute, to blend it together as much as possible. And

  • that’s it. Just by adding a little baking soda, weve modified the rocket propellent,

  • into a fairly reliable time delay mix thatll burn 1 second for every 1/16th of an inch.

  • I typically use a 5 second delay on my motors, and ended up making a new ram rod to fit that

  • profile. It should be obvious that the delay mix goes in after the white mix, but before

  • the kitty litter end cap. The last step is the ejection charge, and for that we need a little

  • black powder, and a small drill bit. The bit I’m using is a 3/32” bit, and using the

  • modified template we can gauge how deep, well need to drill through the clay plug, to expose

  • the delay mix underneath. This will need to be drilled out by hand the same way we did

  • the nozzle in theSugar Rocketvideo, and it’s important to watch carefully for

  • a trace of white powder, on the tip of the bit. This is our confirmation that were

  • all the way through the clay, so to finish up, let’s drop a bit of black powder down

  • the hole, cover the clay plug a few grains deep, then compact it with a few taps from

  • the wooden rod. This compacted ejection charge should hold firmly in place, and the modified

  • rocket motor is finished. Now, using another acrylic motor, you can see that the instant

  • the burn hits the delay mix, it stops suddenly, and burns dramatically slower for about 5

  • seconds. When it reaches the black powder, though, the charge ignites, with enough power

  • to push out a parachute. The delay can be adjusted for any length of time we need, and

  • the rule of thumb, is a 1/16th of an inch, per second. Well now you know how to modify

  • your sugar motors to have time delays and parachute ejection charges, rather than taking

  • the riskier approach of launching duct tape rockets, and just hoping they don’t hit

  • anything important. Well that’s it for now. If you liked this project, perhaps youll like

  • some of my others. Check them out at www.thekingofrandom.com

  • Hey, if youre across the pond, or in another country, I realize you may not have access

  • to some of these materials, so I’ve got another rocket building project coming up

  • that I guarantee youll be able to do. So keep at eye out for that video coming very

  • soon, and in the mean-time if you still want to build rocket motors like these, I strongly

  • recommend you join a rocket club first, so you don’t get yourself into trouble. There

  • are a lot of regulations and safety precautions that you need to be aware of. One thing I

  • didn’t tell you is that these motors can be modified to work with Estes model rockets

  • as well, but I’m thinking about doing a video on building a rocket with a parachute

  • from scratch, so if youre interested in seeing that, let me know in the comments and

  • I may put together something for next spring. And one final thought. If you have to ask

  • where to get black powder, this definitely isn’t a project you should be playing with

  • yet, but let me just say this. It’s actually easier to find than potassium nitrate. Thanks

  • for watching to the end. I hope you enjoyed what you saw, and I hope to see you around

  • for the next project video. Bye.

In a previous project we used sugar, stump remover, and a little bit of kitty litter,

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B1 中級 美國腔

鄉巴佬火箭 (Redneck Rocketry)

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    何紹愷 發佈於 2021 年 01 月 14 日
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