In a previous project we used sugar, stump remover, and a little bit of kitty litter,
to make “E45 equivalent” rocket motors. In this project we’re 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 they’ll 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 to “lawn 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, it’ll 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 you’re willing to risk the possibility,
of an insurance claim. Ok, to make a parachute ejection charge, we’re 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 what’ll 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 you’ll 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 our “Sugar Rocket” project, 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, we’ve modified the rocket propellent,
into a fairly reliable time delay mix that’ll 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, we’ll 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 the “Sugar Rocket” video, and it’s important to watch carefully for
a trace of white powder, on the tip of the bit. This is our confirmation that we’re
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 you’ll like
some of my others. Check them out at www.thekingofrandom.com
Hey, if you’re 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 you’ll 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 you’re 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.