What is the weight limit for streamer recovery?

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Gunstar

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How heavy can a rocket be and still be viable for using a streamer rather than a parachute?
 
Very good question. I think it will depend on the descent rate velocity for that particular mass of rocket. Apogee newsletter 149 had equations to size chutes for a rocket mass, I don't think they covered streamers. Open Rocket software may help you find a descent rate with a streamer recovery of a certain size streamer, generally if you keep it around 20 feet per second or slightly higher maybe up to 30 feet per second there isn't as a great of a danger. Or around 6.2 m/s +/- a few... If you wanted to look at raw energy you could use the kinetic energy formula KE=0.5*mass*velocity^2. So even a light rocket has a lot of energy if its going past the sound barrier i.e. supersonic. You'll find some high power rockets that are lightweight and small diameter with extremely high velocities have more energy during boost/burnout than some firearm projectiles do leaving muzzle. Not trying to scary anybody but I think that's what they are worried about when a rocket descends too fast is the kinetic energy it can carry, while not as a high as launch is what can harm if it was to contact a person for example. The lower power rockets are generally plastic and cardboard which should crumple and not harm as bad. The higher power ones can include fiberglass, plastics, aluminum, and other materials that have dented cars and put holes in ground up to possibility to pierce people absolute worst case (multistage rocket sustainer ignition by timer pointing down/ballistic impact failed chute ejection charge).

For high power rockets there's an RSO checking your rocket and generally a sim file before flight to ensure it won't harm someone, so they would look at rail exit velocity, stability margin, rocket is weighed for a certification, inspected for build errors, and also the descent rate is checked. People have failed high power certifications for too high of descent rate that has destroyed the rocket on landing. (Shock cord snap/Tangled chute/Or the horrid too low ejection charge and rocket nosedives nose attached). But for low power and mid power its like unregulated at user discretion out side of a high power launch site. Maybe NAR/TRA/CAR launch sites or other forum members could give you some feedback. Hopefully someone more experienced sorts you out.
 
Most I, personally, ever recovered on a streamer as primary recovery was in the neighborhood of 5 lbs. That was on a QRS-36.

Streamers really excel at apogee events in traditional dual-deploy setups. Makes it much easier to visually track. I used them on both my L2 and L3 cert flights. Even though my L3 bird was 11' tall on a 7.5" airframe, you saw the streamer WELL before the airframe components as it descended--and that was only a QRS-24.

Do you have a particular project in mind for streamer recovery?


Later!

--Coop

QRS-36.jpg
Graph of the Paramedichutes QRS-36
(with thanks to BJ)
 
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