Simple Parachute Deployment
Posted: Thu Aug 04, 2016 2:02 pm
I've been brainstorming a simple (I.e. Non-electronic) parachute deploy system that could be easily integrated into a 2l rocket. Would love any feedback or advice from others.
I've tried weighting the nose cone to encourage it to slip off during deceleration/apogee. It turned out to be unreliable and we ended up with quite a few lawn-dart landings... The cone had a very loose fit such that inverting the rocket would cause the cone to fall off. It appears that the air pressure held the cone to the rocket. I expect that increasing the drag on the rocket body may help this, however this leads to another problem...
A second system tried involved adjusting the weight balance of the rocket to behave like a backglider, but with an air flap mounted to the lip of the nose cone. The thought being the flap would offer minimal resistance during launch, but offer greater resistance through apogee and descent. The flap would act to lever the cone off the body deploying the chute. The cone again had a loose fit such that even the weight of the chute would pop the cone off if inverted while stationary. We had a great record with this deploy method even while reducing the flap size to minimal. The main issue was during higher pressure launches, the cone would sometimes be ripped off/lifted off during launch shortly after burnout. We ended up with many early deployments and one shredded chute Our next test will be to snug the cone up a bit and test with different flap sizes to find he optimum balance between minimal drag during launch and ease of deployment.
I'm intrigued by the idea of using only air resistance to remove the cone. I have seen more involved deployment mechs using large flaps, etc to open the chute bay. I like the idea of using something that is elegant in it's simplicity
Thanks for any feedback!
-NorthernAir
I've tried weighting the nose cone to encourage it to slip off during deceleration/apogee. It turned out to be unreliable and we ended up with quite a few lawn-dart landings... The cone had a very loose fit such that inverting the rocket would cause the cone to fall off. It appears that the air pressure held the cone to the rocket. I expect that increasing the drag on the rocket body may help this, however this leads to another problem...
A second system tried involved adjusting the weight balance of the rocket to behave like a backglider, but with an air flap mounted to the lip of the nose cone. The thought being the flap would offer minimal resistance during launch, but offer greater resistance through apogee and descent. The flap would act to lever the cone off the body deploying the chute. The cone again had a loose fit such that even the weight of the chute would pop the cone off if inverted while stationary. We had a great record with this deploy method even while reducing the flap size to minimal. The main issue was during higher pressure launches, the cone would sometimes be ripped off/lifted off during launch shortly after burnout. We ended up with many early deployments and one shredded chute Our next test will be to snug the cone up a bit and test with different flap sizes to find he optimum balance between minimal drag during launch and ease of deployment.
I'm intrigued by the idea of using only air resistance to remove the cone. I have seen more involved deployment mechs using large flaps, etc to open the chute bay. I like the idea of using something that is elegant in it's simplicity
Thanks for any feedback!
-NorthernAir