I flew my first dual deploy rocket for the first time a few months ago. I lost sight of it on the way down, but upon reviewing the altitude data from the on-board log I saw that it showed a steady descent from apogee instead of a fast descent followed by a slow descent which would be consistent with a low altitude deployment of the main. Thus, I concluded that the main deployed at apogee, but I'm unsure as to why, or more importantly: how to prevent it from happening again.
Here's my setup: 2.6" diameter, 54mm motor, forward main, aft drogue. I had custom electronics controlling the ejection charges (the log showed that the charges were fired at the correct time) so as a simple insurance plan I left the motor ejection charge in. FWIW, in the ground tests that I performed beforehand the drogue deployment worked as intended and did not also deploy the main. These are the possible scenarios that I can come up with:
I'm really just grasping at straws here though. My question for those more experienced with dual deployment than myself is: Are any of these scenarios likely? What is the usual cause of main deployments at apogee and how can they be prevented?
Any advice is greatly appreciated. Thank you!
Here's my setup: 2.6" diameter, 54mm motor, forward main, aft drogue. I had custom electronics controlling the ejection charges (the log showed that the charges were fired at the correct time) so as a simple insurance plan I left the motor ejection charge in. FWIW, in the ground tests that I performed beforehand the drogue deployment worked as intended and did not also deploy the main. These are the possible scenarios that I can come up with:
- The motor ejection charge fired before the electronics controlled drogue charge causing the main to deploy with the drogue.
- I put too much black powder in the drogue charge resulting in the main also deploying.
- The drogue charge fired after the motor charge had already separated the rocket causing the main to deploy at this time.
- I simply got unlucky.
I'm really just grasping at straws here though. My question for those more experienced with dual deployment than myself is: Are any of these scenarios likely? What is the usual cause of main deployments at apogee and how can they be prevented?
Any advice is greatly appreciated. Thank you!