Balcony Shoot #44 - 2 Stage (FeTi and Al) Wheel
Date: 2004-07-06
Description
I threw this wheel together as a quick pyro-fix for my birthday.
The driver casings where 5 mm ID, 50 mm long, hand rolled from several turns of 95 gsm virgin kraft and dilute PVA paste. The clay plugs were my usual wax treated clay, the nozzle and passfire holes drilled by hand using a 2 mm drill.
The match pipe was folded from the same 95 gsm kraft. Two sticks of pretty average quality blackmatch were used. The drivers were matched with a short length of blackmatch and meal/NC paste priming. The quickmatch was threaded over these driver matchings and 'nosed' with masking tape. The main fuse was a longer length of blackmatch also glued in place with with meal/NC priming.
The first driver was charged with FeTi Driver composition, the second with an experimental Al Driver composition (with black Copper Oxide) I've been working on, mainly as a go-getter star composition.
A tongue depressor was used as a structural element, and hot-melt glue used to attach the drivers.
Comments
Worked pretty well.
The very noticable failure was the Al driver composition burning through its casing. It burns *very* hot, so this kind of failure (as I mention on the video) was largely expected when using such thin 'bottle rocket' style cases.
When the quickmatch between the drivers blew it wrenched the FeTi driver off the stick. It was recovered close by, interestingly the FeTi driver wall was also breached. Strange that it wasn't really obvious in the video, perhaps it happened while the dreggs of the FeTi composition burned away with the driver on the ground? The irregular FeTi effect is likely because of partial seperation of metal from the composition while loading, small tubes allow the dense metal to fall to the bottom of an increment before compacting.
The choice of hot-melt alone to hold the drivers was a poor one, especially with the high temperature Al driver which melted itself off the stick shortly after burn-out.
Thicker case walls should fix the burn-through problems. The Al effect was quite OK, a pure silver compared to the mixed effect of the FeTi.
A nice triangle wheel might go Firefly to FeTi to Al (and finish with a salute?). I might try some colour lances on the next wheel, perhaps a dim charcoal driver with some bright purple or greens?
Attachments
| title | type | size |
|---|---|---|
| Video | video/x-msvideo | 7.973 Mbytes |
| Pre-Test Picture | image/jpeg | 41.751 kbytes |
| Post-Mortem Picture 1 | image/jpeg | 52.544 kbytes |
| Post-Mortem Picture 2 | image/jpeg | 23.594 kbytes |