When I was making up the hummers I had a brain-wave, I figured it wasn't much of a jump to ram one on the rocket mandrel and drill the spin vent just above the clay plug.
The case was 37 mm long, 8 mm ID, 20 mm OD. Bottom plug/lift nozzle of wax-treated cat litter, bulkhead seal of wadding and hot-melt. 1.8 mm spin vent, drilled in just above the clay.
Fused with thin blackmatch and a little meal-NC paste. Propellant was my standard Aluminium modified blackpowder rocket meal.
Launching pin was the steel wire off a sparker, arranged with a bamboo spike for sticking in the sand.
Worked well!
Screamed and took off into the air with a umbrella shaped tail of charcoal and Aluminium effects. Very straight and well-behaved flight.
Note the spectrogram of the audio recovered. The fundametal peaks at 850 Hz before it gets doppler shifted by the lift acceleration. That is an *amazing* 51000 RPM! That can't be right, but the data seems to say it is. Sounds like a dentist's drill. The hummer made a similar sound, but longer in duration, it will be interesting to recover the sound from a future hummer test.
Not sure how high it went, it was only about 30 metres up at burn-out, but I heard it land some 3 seconds later, fortunately the ocean was fairly calm and quiet. It was still spinning when it landed, and rolled along the ground until it hit a concrete ramp where I later found it (a small miracle in the dark).
Note in the post-mortem picture #1 that the dross has been flung out by the rapid rotation. Still 51 kRPM seems an amazing figure.
Gotta make more of these, so easy to make, great performance, sound, sparks, flight, love it.
| title | type | size |
|---|---|---|
| Flight Video | video/x-msvideo | 336.906 kbytes |
| Spectrogram Picture | image/jpeg | 37.162 kbytes |
| Pre-Test Picture #1 | image/jpeg | 34.962 kbytes |
| Pre-Test Picture #2 | image/jpeg | 57.618 kbytes |
| Post-Mortem Picture #1 | image/jpeg | 45.638 kbytes |
| Post-Mortem Picture #2 | image/jpeg | 39.280 kbytes |