The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
  1. R3verb

    Help sizing BP charges for a BT-60 tube

    Hey Everyone, I'm working on an Estes Star Orbiter that I've heavily modified to include DD. This is my first experience with DD and I'm having some issues with getting the charges to pop the drogue out. I did some pop tests today with mixed results. I'm using the Christmas lights ejection...
  2. C

    New Method for Parachute Deployment? Deployment by Rocket Extraction

    I am a member of a newly founded rocketry team in my University. We are very excited to build our first rocket, however, we have no prior knowledge. Upon investigating different methods for Dual Deployment Systems, Theo W. Knacke in his book "Parachute Recovery System Design Manual" mentions a...
  3. Dufus Johnson

    Ejection charge only works when bay is empty

    Howdy, folks... new to the forum. I'm L1 and going for L2 and I'm trying dual deployment for the first time. Only ground testing so far and have mixed results. Basically if I try the calculated amount of BP on an empty bay, it shears the pins and ejects the nose cone quite forcefully. If I...
  4. Nacho

    Will ejection charge corrode electronics?

    Hi all, I was wondering, how bad is it to expose electronics to the fumes of the ejection charge (this would be for a C motor). Thanks! :)
  5. jahall4

    Shear pins on a 8" dia bird.

    I’ve been using this Ejection Charge and Shear Pin Calculator for my fiberglass projects and its recommendations have always been confirmed in ground testing. https://www.rimworld.com/nassarocketry/tools/chargecalc/index.html However, I’m working on an 8” dia project that may end up using #6...
  6. ArchitectOfSeven

    Ideal pyrodex charge?

    Hi all, I'm trying to set up some pyrodex ejection charges in 2ml centrifuge vials and want to know how well I should try to contain the powder. With the vial completely full (~1.8g), and sealed with quite a bit of masking tape it went off with a sound a lot like a gunshot in a preliminary...
  7. jahall4

    Using Pratt Ejection Canisters in L3 size rockets flying over 10K

    I have a fair amount of very successful experience using prat ejection canisters up to 5K. Anyone with experience using them over 10K?
  8. Gary Mac

    Pratt Ejection Canisters

    Have there been a lot of positive experiences with the Pratt Ejection Canisters? From reading online, they are reusable and used to trigger ejection charges without requiring or consuming a separate electric match (sounds like you pack them full of black powder, and they have a wire that gets...