How can I slow deployment?

[tim cubbedge]

In the future, separation and deployment (my prediction) will be entirely electronic (i.e. not black powder, just electronic). Your rocket will separate at apogee, and your chute will open when you want it to (e.g. Chute Release). We have the second part already, the first part (electronic deployment) will come at some point. In the future, you'll buy motors just for the "up" part, not the deployment part. They are not particularly good at that...

Plugged motors only give you the up part. Regardless of the chute release, still need pyro of some sort to pop that chute!

 

[cerving]

Plugged motors only give you the up part. Regardless of the chute release, still need pyro of some sort to pop that chute!

Not necessarily, there are plenty of non-pyro ways of getting the chute out. Trap doors, spring-loaded NC's, CO2 systems, etc. Problem with them is that you basically have to design the rocket around them... with motor eject, you don't. Plus, motor eject is basically free, and weighs virtually nothing.

Pyro deployment is cheap and has been around for as long as there have been model rocket motors. It ain't going away anytime soon.

 

[sl98]

Other than the obvious answer...longer delay charge, if I sim out a rocket for ideal delay at 11.5 seconds and the longest delay is 10 seconds how can I slow down the chute from opening?

My thoughts so far
A)longer shock cord
B)small chute to open before initial shock
C)bridging rubber bands
D)chute release but it isn't feasible yet. not in budget (yet) and won't fit with altimeter and 15' of shock cord.

Did you try adding a little weight to the rocket sim? Added weight should decrease coast time.

 

[Banzai88]

Not necessarily, there are plenty of non-pyro ways of getting the chute out. Trap doors, spring-loaded NC's, CO2 systems, etc. Problem with them is that you basically have to design the rocket around them... with motor eject, you don't. Plus, motor eject is basically free, and weighs virtually nothing.

Pyro deployment is cheap and has been around for as long as there have been model rocket motors. It ain't going away anytime soon.

The simple solution is often the best solution!

 

[AfterBurners]

Add more nose weight

 

[ksaves2]

There is a parachute slipknot braid I saw in one of the rocket magazines one time. There is an Apogee video on it using a crochet needle for a modroc but one can do this braid by hand with a large chute without a needle: [video=youtube;ETiB_V-_SGs]https://www.youtube.com/watch?v=ETiB_V-_SGs[/video]

I've used it with parachute shroud lines in the past but have to see if I can find the reference. Some use masking tape that breaks as the shockcord uncoils. Again there is no guarantee with this if purposely going for a late ejection.
If a glass rocket with a stout harness that provides some insurance with late deployment. I had a Jart with a 29mm motor end up with a late delay and it was coming down very fast. It's such a short rocket, I used a ring on the nosecone and stuff the
liberally long shockcord in the nosecone. There is some resistance as it uncoils out of the NC but I haven't had an issue with it. Kurt

 

[dford]

It has been a minute since I last posted anything on the issue. I have launched the rocket several times successfully until the last time when I put a camera on the side. It went unstable.

Back to the point. I found it a bit comical ( in a good way ) ksaves posted the above video. I certainly had to crochet the shock cord. No way it would fit into the very small space with the parachute. I heard an ill argument to crocheting shock cords and it was only due to the friction upon deployment.
I also decided to put a smaller G motor rather the G76 simply to keep the actually flight a little less on the initial flights. I think the longer crocheted shock cord takes time to open AND slows down the rocket gradually before the initial shock of parachute deployment.
In my opinion G motors should come with S (4), M (7), L (10), and "XL" (12/14) long delays to alleviate high altitude flights on high thrust motors.

I plan to repair the 18" rocket into roughly a 20" rocket and throw it up on the original planned G76 next saturday as long as I can get my motor order here in time. The extra two inches plus added weight to fix the nose attachment point seems to slow it down to a 10.7 delay and just over 3700' on a G76 or mach+ and nearly 5000' feet on a G138-14 drilled down. But the G138 altitude would probably cause a lost rocket and a lost cause. Besides, i'm not real sure this paper rocket can handle those kinds of forces.