Charges — What’s Everyone’s Experience

[Steve JensenParticipant]

combined with a bit of science.

Having over charged my Little Dog Dual Deploy, I got so much velocity from the apogee deployment charge on my booster section that it sped away from the rest of the rocket with enough energy to cut the shear pins on the fore section, straighten out my eye hook, and cause separation of the booster from the fore section. This resulted in a four mile jaunt to retrieve the fore section, which was only found due to my DC-30.

The booster was eventually found (Thanks Bryan Schmidt in another forum).

Tribal knowledge from the club also helped me understand what had occurred (thanks Ken Riley).

It just proves that I am still learning and thus the creation of this thread.

This is fun. Thanks to all.

[Bruce R. Schaefer]

LS, you may have over-estimated our going above the calculated charge, four miles? Dude, even JW who set off car alarms for miles may even frown on that. Scale that puppy back! 🙂

[Steve JensenParticipant]

separated at apogee and the chute came out at 10,500 feet (or so) the unlimbered chute carried it 2+ miles directly over the windmill to the northeast.

Deployment of the main at apogee was bad. Separation of booster from fore section was bad. Straightening out the eye hook hurt too.

Without the DC-30, I would have lost the entire thing.

Another learning experience. I’ve since launched it but with half the drogue deployment charge and larger shear pins in the fore section containing the main chute.

You can over charge with bad results other than blowing the tube. The fiberglass held up well. I also will used forged eye bolts or weld/braze them shut. A learning experience to say the least.

[sserell]

I’m a fan of pistons for the getting the main laundry out. Here’s a great article on piston design.

http://deltavrocketry.com/piston.htm

I employ the “inverted” piston, bulkhead on the bottom with the coupler tube above it. Prevents binding due to expansion of the coupler or from wobble. I also am a fan of “big” charges, especially at apogee, I went a little “too” big at balls this year and blew a poorly glued bulkhead a little bit with the charge, which ended up kicking out my motor casing, which we luckily found.

[Bruce R. Schaefer]

This is what is absolutely amazing about this hobby, there is no ONE answer. Each of us has different experiences; each rocket is different, as is each motor…. isn’t this fun?

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