Monday Sep 24, 2007

First Launch

I finally launched my LOC Vulcanite rocket for the first time. The results were outstanding.

I blogged about my Vulcanite earlier this year. This rocket is 53" tall (4.5 ft, 135 cm) and weighs 32 oz (2 pounds, about 1 kg) before adding a motor. I painted it orange and black to make it more visible against blue sky or light clouds.

My goals for this rocket include:

  1. determining that it is flight worthy
  2. obtaining my Level 1 certification
  3. gaining experience with high-power motors
  4. flying a rocket to one mile (1.6 km) altitude
  5. if it seems that the rocket will survive Mach 1, attempt to do so
On the day I first launched it, I achieved (1), (2) and (3). The first launch, and L1 certification attempt, was on an AeroTech H73J. This motor weighs 10 ounces when ready for launch, and is about 6" (15 cm) long. It provides 16 pounds of force at liftoff, sufficient to launch this rocket easily, but not so much that I have far to walk if it decides to become a "cruise missile" by turning and flying horizontally.

The results were gratifying.

(When I take pictures of a launch, I press the shutter as soon as I see any vertical movement, which resulted in a well-composed picture. At least it did this time...)

According to the on-board altimeter I added, it flew to 1,584 feet (480 m). More importantly, it flew almost perfectly straight up, and the 24-inch parachute returned it safely to Earth not far away from the launch rail. However, it seems that the delay I chose - the time before the parachute is ejected - was not long enough. With the correct delay, the rocket would have flown higher.

Beaming with success, I decided that the next launch would begin to test the limits of this rocket. I chose an I218R - an 8-inch (20 cm) motor with almost twice the total impulse of the previous motor. (Think of total impulse as the total force exerted while the motor is burning.) Even though I knew it would fly much higher, the wind was very light that day, so I didn't expect to walk far to recover it.

With this motor, the Vulcanite flew to 4,469 feet (1.35 km)! Also impressive was its maximum speed: over 500 MPH (800 km/h). You can see that in the picture to the right: I have an itchy shutter finger, but the rocket launched so fast I missed it entirely!

Unfortunately, although the nose cone ejected properly, the parachute never came out. The two ends of the rocket, connected by an elastic cord, fell over 4,000 feet to the ground. Fortunately, the launch area was an empty corn field with large clods of dirt which had been softened by rain the day before. The only damage was a partial crack in one plywood fin. A little sanding, some new epoxy, and it should fly again.

To one mile?

About

Jeff Victor writes this blog to help you understand Oracle's Solaris and virtualization technologies.

The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.

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