Has anyone experimented with spring or other non-explosive parachute ejection?

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Hal8472

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Mostly from a technical curiosity point of view I am exploring options. Any system that can power an igniter can be modified to drive a motor or latch. Has anyone gone this route?
Andrew
 
A saw a system that used a piston and a surgical rubber band. The band or bands were pulled tight and connected to a thin piece of steel foil (not steel wool) like the type used in cleaning pots and pans.
When activated the battery current would melt the steel foil releasing the piston.

Steve G
 
There are those who use CO2 for their systems, but I don't know much about it.
 
Sure:
There are lots of different ways to deploy a chute or streamer using springs, rubberband activated latches and/or slide open side doors. Quite a few PMC's use unusually deployment methods.
 
I now have a new respect for water rockets. I had no idea.

Thanks
Andrew
 
Mostly from a technical curiosity point of view I am exploring options. Any system that can power an igniter can be modified to drive a motor or latch. Has anyone gone this route?
Andrew

My 100% pyroless deployment device that I've been flying since 2010
https://www.propulsionlabs.com.au/Pyroless_Release/

This is used in conduction with a larger latch mechanism of similar design to provide 100% pyroless dual deployment in my 90mm HPR rockets.

and the 100% pyroless separation system I developed for the 1:1 scale V2 rocket launched earlier on in the year:
[video=youtube;y7HT6eOhUOU]https://www.youtube.com/watch?v=y7HT6eOhUOU"]https://www.youtube.com/watch?v=y7HT6eOhUOU[/video]

Troy
 
Troy
Looks excellent. Would you perhaps sell any of these units?
 
I did some ejections using compressed air.
Air was in a plastic soda bottle at 120 psi, valved using thick tape as a burst disc. An e-match heated the tape till it fails releasing the air. Parts were way more complicated than this description.
Plan was to replace the e-match with a hot wire but it didn't happen.

M
 
Way back when, Estes has a series of rockets powered by freon. The ejection was by spring power, and held in place by two "bladders" that were inflated by the freon in the engine.
 
Way back when, Estes has a series of rockets powered by freon. The ejection was by spring power, and held in place by two "bladders" that were inflated by the freon in the engine.

Estes or Vashon? iirc Vashon had the cold power and Estes has always been BP or Composite motors. I however am not real familiar with Estes products prior to 1975.
 
Estes or Vashon? iirc Vashon had the cold power and Estes has always been BP or Composite motors. I however am not real familiar with Estes products prior to 1975.

Estes bought the Vashon line and sold it for a few years under the Cold Power line - they sold both the Valkyrie I and II rockets plus several models that had a cold power motor inside a standard paper body tube (these were convertable and would fly on either freon or you could put a regular BP motor in instead). Check out the 1973 catalog on Ninfinger for the entire line.
 
Estes bought the Vashon line and sold it for a few years under the Cold Power line - they sold both the Valkyrie I and II rockets plus several models that had a cold power motor inside a standard paper body tube (these were convertable and would fly on either freon or you could put a regular BP motor in instead). Check out the 1973 catalog on Ninfinger for the entire line.

Thanks for the references, I had no idea Estes acquired Vashon.
 
I did some ejections using compressed air.
Air was in a plastic soda bottle at 120 psi, valved using thick tape as a burst disc. An e-match heated the tape till it fails releasing the air. Parts were way more complicated than this description.
Plan was to replace the e-match with a hot wire but it didn't happen.

M

Oooh, this gives me an idea. As you go up ambient pressure goes down, right? You can tune the pressure and seal disk strength so the bottle would release pressure at a specific altitude :=)

OK, I'm going away now.

Ari.
 
Estes bought the Vashon line and sold it for a few years under the Cold Power line - they sold both the Valkyrie I and II rockets plus several models that had a cold power motor inside a standard paper body tube (these were convertable and would fly on either freon or you could put a regular BP motor in instead). Check out the 1973 catalog on Ninfinger for the entire line.

I actually built and flew one of the Estes kits that were designed to make use of the cold propellant/Freon motor. The ejection process using the deflating bladder and spring to push the chute out after the pressure was gone was spotty. Worked once and did not work the other two times I flew the model under cold power, thus contributing to the drawdown of our all important ozone layer...:)
 
Oooh, this gives me an idea. As you go up ambient pressure goes down, right? You can tune the pressure and seal disk strength so the bottle would release pressure at a specific altitude :=)

OK, I'm going away now.

Ari.

Of course, the problem is that you generally want to deploy when the rocket (or whatever) starts descending so you're comfortable that you've already achieved your apogee. What's more, you ideally want that process to happen as close to apogee as possible, so (assuming you're utilising barometric pressure) you're force to rely on a detection mechanism that's highly sensitive to baro pressure variations and is highly accurate which pretty much confines your to electronics (sensitive baro senses with amplification stages).
What's more (still), getting a mechanical structure to break/fail at a specific pressure working on such a low pressure differential is incredibly challenging (without utilising immense surface areas).

Of course, I'm suspecting the idea was mostly tongue in cheek, but nevertheless...

Troy
 
I timed a TARC team that used a cable cutter and a spring-loaded piston to eject their parachute. The cable cutter was an OOP model that used a hot wire rather than pyro effects to cut the cable tie. (If I recall correctly, TARC rules state that no pyro events are allowed after launch.)

I think this is the same sort of idea that Jolly Logic is going to have in production within the next month or two. https://www.rocketryforum.com/showthread.php?128806-Sneak-Peak-Jolly-Logic-s-Easy-Dual-Deployment
 
The Jolly Logic unit twists a servo to release s rubber band. It works well and I like it quite a bit, but it will not help for airframe separation.
 
I created Chute Release in time to use it for my L2.

If I ever decide to step up to the L3, I'll develop an electronic separation product in time for that. I'd love to get rid of the soot and ejection damage on my rockets and parachutes. If you think about it, it's time we just bought engines that focused on the "up" part, and stopped futzing with them to set an estimated ejection delay.
 
I created Chute Release in time to use it for my L2.

If I ever decide to step up to the L3, I'll develop an electronic separation product in time for that. I'd love to get rid of the soot and ejection damage on my rockets and parachutes. If you think about it, it's time we just bought engines that focused on the "up" part, and stopped futzing with them to set an estimated ejection delay.

+1!!!!! Seems like with the ingenuity we have in our hobby we should be able to figure this one out. The advances in electronics and materials over the last 20 years, especially, have made it possible to do really amazing things.
 
Hopefully early next year I'll produce a small production run. Well... I need something to justify the hobby lathe I'm in the process of purchasing :) It was suppose to happen this year, but moving house and twin babies killed that idea.

Troy
congrats on the twins Troy, I had a couple of quite year rocketry wise after our twins were born...

The V2 deployment BTW was brilliant. Pretty sure the nose got an extra 50 feet or so when ejected.
 
congrats on the twins Troy, I had a couple of quite year rocketry wise after our twins were born...

The V2 deployment BTW was brilliant. Pretty sure the nose got an extra 50 feet or so when ejected.

Thanks Mat! Yeah, you can certainly relate then to what a handful they can be:)

Yeah, the V2 separation was certainly a challenge - especially after finding out what the final expected altitude we were looking at was. The whole event was great.

Cheers,

Troy
 
My 100% pyroless deployment device that I've been flying since 2010
https://www.propulsionlabs.com.au/Pyroless_Release/

This is used in conduction with a larger latch mechanism of similar design to provide 100% pyroless dual deployment in my 90mm HPR rockets.

and the 100% pyroless separation system I developed for the 1:1 scale V2 rocket launched earlier on in the year:
[video=youtube;y7HT6eOhUOU]https://www.youtube.com/watch?v=y7HT6eOhUOU"]https://www.youtube.com/watch?v=y7HT6eOhUOU[/video]

Troy
Very clever. Well done.

Two questions.

1.) Did you explore the option of including the 8 or 16 g CO2 cylinders into your design to eliminate the need for a filling system?

2.) Did you consider using a gas piston ram to push off the NC versus pressurizing the airframe volume?

You mechanical release mechanism is simple and elegant. :clap::clap::clap::clap::clap::clap:

Bob
 
Very clever. Well done.

Two questions.

1.) Did you explore the option of including the 8 or 16 g CO2 cylinders into your design to eliminate the need for a filling system?

2.) Did you consider using a gas piston ram to push off the NC versus pressurizing the airframe volume?

You mechanical release mechanism is simple and elegant. :clap::clap::clap::clap::clap::clap:

Bob

Bob,
I did entertain the idea of including the consumer packaged cylinder/bulb within the device and it’s still not an idea I’ve completely ruled out. There are certainly quite a few virtues for including that but there are also some cons:
The inclusion of the cylinder/bulb does add extra weight to the device as you’re effectively carrying along 2 high pressure containment structures although those 8g bulbs are pretty damn light.
However the more important issue is the flow rate of the working gas from the device when activated: the fundamental concept behind the design was to provide a massive flow rate from the device to replicate a pyrotechnic charge ie. To maximize the energy utilization (by maximizing power) of the gas contained within the device so the separation mechanism isn’t just a pressure>force one, but also utilizes momentum of the gas and associated laundry within the airframe volume exposed to this process to assist separation and deployment. A high flow rate also minimizes any detrimental effect any leaks could have in the airframe coupling or breather holes within the airframe.
So, to ensure we get all of that gas out as instantly as possible, we need to contain the entire gas contents within a containment that has full access (unrestricted) to the main (high flow) valve port. So, the problem with carrying the bulb along is the orifice that gets pierced (of the bulb) will always be of much a smaller area in comparison to the main valve port and however you attach the bulb to the system, a substantial fraction of the gas contents of the device will remain inside the bulb when/if the device is pressurized.
The pyro actuated CO2 devices work reasonably well because they can utilise the immense force from the pyro charge (driving a tapered pin) to really open up that orifice as wide as possible to maximise the flow rate through the orifice.
So, that’s my rationale behind the exclusion of the bulb, but I’ll openly concede it’s far from bulletproof.

For the 2nd question: when you say "gas piston ram", can you possibly elaborate on that? I think I know what you're suggesting, but would like to be sure.

Thanks,

Troy
 
I have been doodling around and doing some sketches for an electromechanical device for airframe separation. No springs or rubber bands.

Electric motor and jackscrew system that separates the airframe. First one likely to be RC activated for tests up to 2k feet or so.

Probably a little too Rube Goldberg for the average rocketeer, but will be fun to make it work. RC servo and elastic band dual deploy as well.
 
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