Lift off Dart Rocket

These are photographs taken of the first launches of the Dart rocket.

What a first launch. Having worked it through on the simulator, I decided to run the first launch at 100psi. On the left, the dart is sitting on the top of the connector which just slots into place in the cut top of the bottle which is taped to the pressure vessel (tested to 140psi full of water). You can see the nose is a nice shape and you can just make out the fins. The dart simply rests on the connector.

Taking into account the fact that the fields were deserted, I decided that as I was the only human the dart could hit, I would be safer if I was to aim it away from where I was standing so I put around a 10 degree from vertical angle on it which would make it miss me by at least 50 yards.

So, I pumped it up, got the camera out and, while looking at the launcher through the viewfinder and standing at a safe distance, I pulled the release string. The thing disappeared straight away and I soon saw the booster falling back to earth, close to the launcher so I looked up. I couldn't see it anywhere so I stood still and listened. What seemed like a good 10 seconds later, there was a distant thud and I had some idea of where to look.

After 20 minutes of searching the football pitches (I was determined to get it - I wasn't going to go home without it), finding assorted leaves and wondering just how far it was burried (was there just a hole - some parts of the ground were that soft), I eventually found it with the nose burried 6 inches into the turf, half way up a small hill.

It took some force to get it out of the ground but the nose wasn't damaged, except for a small slight scratch which was probably caused by a stone in the ground.

I paced the distance back to the launcher and it turned out to be 121 yards

Back at the launcher, the landing site looks so improbable and if it had gone only another couple of yards, it would have gone into the longer grass and I would never have found it (it makes you wonder what someone would have thought later on the next year as they discovered it if I hadn't managed to find it).

The first launch was close to perfect (apart from trying to find the dart afterwards) and subsequent launches were made at substantially lower pressures. These showed a tendency to separate late - the coefficient of drag on the booster clearly being too low - there is nothing to go wrong with the connector. I'll possibly use air brakes on the booster next time.


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