Saturday, April 02, 2005

Further Zig Adventures

More rocket fun cominatcha!

A few more evenings in the garage this week resulted in two new rockets in need of testing. Saturday just happened to yield perfect conditions; clear blue skies and very little wind. Let's go!

Rocket 1, designed with reliability rather than outright performance in mind, I'll refer to as the Orange Flaming Thing (OFT) due to it's excellent colour scheme created by Syn. The design was quite similar to last week's long rocket which flew very well.



Rocket 2 was a bit more adventurous, with a minimum diameter body and highly swept fins, which I'll call Dart-Like Object (DLO). The position of the fins further forward resulted in the need for a little weight in the nose to make it stable unfortunately. With recovery streamer in place it weighed in at 48 grams, 1 gram heavier than OFT. I don't have a "before" photo of DLO.

First off I decided to launch the DLO, leaving the more conservative OFT in reserve in case DLO went funny. I needn't have worried, liftoff was perfect and the flight spectacular. See sequence below or download the video. A big thanks to Adrian for again acting as cameraman.













The recovery streamer popped out and the rocket eventually came to Earth in the middle of the creek, fortunately dry. Thanks to Chris for recovering it from a very scary, evil spider infested place.

Next up was OFT. This time I handed over launch button duties to Adrian and manned the camera in an attempt to shoot continuous still frames of the launch. Liftoff was good, unfortunately occuring between frames, but the flight did not go to plan. A few hundred feet up while still under power the rocket made a violent left turn and broke up. By sheer luck I managed to capture this on camera..





Soon after it started to rain small rocket parts. We managed to recover most of it, except for the streamer, one and a half fins and a piece of the body.

I'm still not certain what went wrong, I've been examining the pictures closely but can't conclusively identify the first part to break off. It's either:

-A section of body near the nose that's split and lifted, then been torn off by the airstream. The rocket then yawed, pulling off the nosecone, dragging out the streamer and causing two fins to fail.

OR

- A fin has failed at the root, causing the same yaw and subsequent breakup as mentioned above.

The first piece to break off looks white, indicating a section of the body, but I can't see where the other fin went either, so it could be the fin as seen from end on, with bare balsa showing.. In any case it was a quite spectacular failure. Thanks again Chris for venturing into the Planet of the Spiders to retrieve bits.

A minor repair was made to DLO before readying it for another launch. Again, liftoff was excellent but the streamer failed to deploy. It seemed to have jammed on the way out, so the rocket came down at great speed, through a tree canopy and stuck into the grass, still smouldering.



It was pretty smashed up, the engine having gone for a walk to the nose cone, splitting the body lengthwise, but I'll probably repair it.

Anyway, despite the carnage it was a pretty successful outing. And yes, I'm afraid there will be more to come. The next challenge (apart from improving durability and reliability) is to cram a baby digital camera in one and shoot the liftoff from the rocket's perspective.. Stay tuned..