There it is on its first test run.  I was pretty unsure of its capabilities, so I didn't go crazy on the engine choice.  Basically
I just shove in a standard solid rocket engine.  This first time, I used a C engine.  I'd say it was ok, I got a feel
for how it would react.  I felt it was safe to bump up the engine size to an E.  An E is the largest I can get ahold of
locally, and it's bigger so I had to modify the rear with bigger tubing.  For an idea of power output, for the engine sizes A
through E, each following letter is twice as powerful as the previous.  Little rockets like those we all built in shop class
generally stick to A's and maybe B's.

Here's a look at the rear.  Ya just pop the engine in, put in the hitch pin, and you are ready to go.  Once it's
fired, there's no stopping it, the engine runs till it has no more fuel.  When it uses the last of the propellant, it fires
a parachute charge in the opposite direction, hence the shape of the tubing.  

This thing hauls butt.  Like I said once it's fired, there's not much you can do if it starts turning toward a
bunch of kids. To date, its had two ummm...accidents.  You may notice the nose points up a bit.  On one of it's first few runs, the parachute didn't make it out because it had been packed in too tight.  Well it kept going and smacked a curb maybe around 80-90 mph.  The thing flipped up about 15 feet in the air and left quite a mark on the curb.  Luckily that was the only damage.
For the second, imagine something like this going that fast on a perfectly smooth parking lot, and it hits a small rock.
This small rock flipped it right over halfway into the run, and the engine continued pushing.  The sparks were pretty cool, so it wasn't all for nothing.  You can see in the picture of the rear, the fins are eaten up a little on top.  I used to have a little plastic guy glued to the top for grins, but he didn't make it.