Hi Everybody,
I've been messing around with some builds for a mechanical deployment bay. I've finally got a design that works manually. I can use minimal force to pull a release pin that pops a spring-loaded platform to push out a chute. The spring pushes with about 2 lbs now.
I need to get my hands on a force meter to determine the torque needed to pull the pin, but it feels within the limits of a small, high-torque servo. Once I have the force figured out, I might be able to increase the spring strength.
As for the body, I'll need to cut a side-hatch with hinges and retention magnets to keep it shut until ejection. I've got some small, neodymium disc magnets that will do perfectly for this. Still debating a hinge or a cord to let the hatch fall free and dangle.
Finally, I'm at my weakest personal skill set. I need to figure out a controller (Arduino, maybe?) to turn on the servo using apogee as the triggering event. The servo can run on a 9V battery which should be able to power the controller as well. I'll need to beef up my knowledge here or get help from others.
I think this would work well with the Jolly Logic release to allow a single, spring ejected chute as a drogue that opens at lower altitudes for a safe landing.
Still too scared to risk putting this in one of my precious MPR rockets and risk its ballistic demise.
Plus, this is scaled at 4 inches diameter and 9 inches long right now. Prototypes are fun!
I'd love any feedback; especially on the electronics side.
Materials are:
- plywood for the bulkheads and panels
- threaded rods for the frame
- nylon rods for the 4 platform guides (threaded on the ends with retaining nuts
- ptfe cylinders to hold the spring
- ptfe pull-pin (low friction of ptfe's means easy pull out)
- nylon pulley wheel (pulley vs direct pull = easier)
- metal spring
- kevlar string
- (tbd) high-torque servo
- (tbd) flight controller for altimeter + servo control
- steel nuts, bolts to hold it all together and attach chute shock cord
- 4 x neodymium magnets with 0.25 lb hold force each
Simply push the panel down until the ptfe holes lign up, push the ptfe pin in to hold it together, attach chute. The ptfe tubes and guide rods help keep the push straight so there's no jamming or other oddities. Big downside is the added weight, but it's about 1 lb heavier than a controller + BP ejection standard design. Should be ok.
Thanks!
Mark
NAR#: 100890
I've been messing around with some builds for a mechanical deployment bay. I've finally got a design that works manually. I can use minimal force to pull a release pin that pops a spring-loaded platform to push out a chute. The spring pushes with about 2 lbs now.
I need to get my hands on a force meter to determine the torque needed to pull the pin, but it feels within the limits of a small, high-torque servo. Once I have the force figured out, I might be able to increase the spring strength.
As for the body, I'll need to cut a side-hatch with hinges and retention magnets to keep it shut until ejection. I've got some small, neodymium disc magnets that will do perfectly for this. Still debating a hinge or a cord to let the hatch fall free and dangle.
Finally, I'm at my weakest personal skill set. I need to figure out a controller (Arduino, maybe?) to turn on the servo using apogee as the triggering event. The servo can run on a 9V battery which should be able to power the controller as well. I'll need to beef up my knowledge here or get help from others.
I think this would work well with the Jolly Logic release to allow a single, spring ejected chute as a drogue that opens at lower altitudes for a safe landing.
Still too scared to risk putting this in one of my precious MPR rockets and risk its ballistic demise.
Plus, this is scaled at 4 inches diameter and 9 inches long right now. Prototypes are fun!I'd love any feedback; especially on the electronics side.
Materials are:
- plywood for the bulkheads and panels
- threaded rods for the frame
- nylon rods for the 4 platform guides (threaded on the ends with retaining nuts
- ptfe cylinders to hold the spring
- ptfe pull-pin (low friction of ptfe's means easy pull out)
- nylon pulley wheel (pulley vs direct pull = easier)
- metal spring
- kevlar string
- (tbd) high-torque servo
- (tbd) flight controller for altimeter + servo control
- steel nuts, bolts to hold it all together and attach chute shock cord
- 4 x neodymium magnets with 0.25 lb hold force each
Simply push the panel down until the ptfe holes lign up, push the ptfe pin in to hold it together, attach chute. The ptfe tubes and guide rods help keep the push straight so there's no jamming or other oddities. Big downside is the added weight, but it's about 1 lb heavier than a controller + BP ejection standard design. Should be ok.
Thanks!
Mark
NAR#: 100890
