Red Dot and Christmas Tree E-match
| Ejection Packets Red Dot and Christmas Tree E-match |
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A 3x5 inch index card is folded in the middle. Two adjacent sides are sealed with masking tape or any other suitable tape. It occurs to me that the aluminum foil duct tape would make a moistureproof package, but I have not yet tried it. |
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The ragged edges are trimmed. Neatness counts! |
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Ejection powder is measured out. Here I am using Red
Dot, my favorite. For the 3-inch diameter airframe, I have
settled on 2.5 grams per ejection. This is plenty but not too much. Red Dot is remarkably forgiving of overcharges. I have ground-tested ejection with as much as 10 grams in the 3-inch Quantum-tube airframes with no damage to airframe or parachute. Got good ejection too, by the way! |
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The unsealed edge is opened and a Christmas tree bulb e-match inserted. I am sure any other type of e-match would work. I have used a similar technique with Daveyfire ignitors, with good results. |
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The remaining open edge is sealed with more tape. |
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One more little bit of tape to hold down the wire lead. This is to provide a little bit of "strain relief" and prevent the e-match head from being jerked out of the packet if the parachute load shifts. |
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The note card provides a handy place to write down what this is.... provided that I don't cover the whole surface with tape! This one came close. |
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Red Dot is a "gentle" explosive. Since the pistons in my airframes have been trashed, I've been using a piece of cloth to cover the parachute and protect it from ejection gasses. On my first flight at the March launch, I lost the square of blue-jeans leg that I'd been using for a couple of years and had survived a dozen or so ejections with no serious damage. So I found one of my shop towels in the truck and tied it on. This is that towel after three ejections. It is a bit dirty, but hardly scorched at all. The parachute that was inside it is not damaged in the least. Black powder would have eaten it up. |
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I just thought of a possible explanation for the "unburned powder" problem that is frequently mentioned in reference to smokeless powder ejection. Here is a little Red Dot sprinkled on a 3x5 card. |
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I went over it lightly with a torch, igniting the grains.
I shook off the card and brushed it lightly to make sure any
unburned flakes were removed. The unburned residue looks like little flakes. At a glance, it seems that some of the powder did not burn, but in fact it did. I suspect that the black husks are graphite, added to this powder as a dry lubricant. Smearing the residue with a fingertip gives it that silvery shine characteristic of graphite. Perhaps this is a function of the "self-lubricating" ammunition, in that the powder residue from one shot would serve to lubricate the next. |