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Deployment System

Posted: Mon May 27, 2013 6:22 am
by Arthur Liew
Hi,
I have created a water rocket with a parachute deploy system without using any timer,etc... but the cone doesn't want to come off although it went very high.What should I do?The link for the systme I am using, http://txsnapper.eezway.org/waterrocketguy/ezd.html.

Re: Deployment System

Posted: Mon May 27, 2013 1:12 pm
by Tony
I suggest adding a little more weight to the nosecone.

Re: Deployment System

Posted: Mon May 27, 2013 1:39 pm
by Team Seneca
Tony wrote:I suggest adding a little more weight to the nosecone.
Also try putting a few wraps of tape around the bottle to create a wall the nosecone can't slide past. If you put weight on the nosecone it will push onto the bottle very tight when the rocket blasts off. The tape will keep it from getting pressed on so much it won't come off.

Re: Deployment System

Posted: Mon May 27, 2013 10:28 pm
by Arthur Liew
I have add some weight to the nose cone but still didn't come off.Do I also need to increase the length of the bottle?

Re: Deployment System

Posted: Tue May 28, 2013 12:29 am
by Arthur Liew
I mean do I have to increase the length of the rocket?

Re: Deployment System

Posted: Tue May 28, 2013 12:59 am
by bugwubber
Arthur Liew wrote:I mean do I have to increase the length of the rocket?
Launching straight up or at an angle? How is the rocket falling right after apogee? Ballistic trajectory or back glide with flip to nose down?

Bugwubber

Re: Deployment System

Posted: Tue May 28, 2013 1:53 am
by Arthur Liew
Hi Bugwubber,
I launch it straight up,the nose cone is straight down after apogee.I am using a 1.5litre bottle for the rocket.

Re: Deployment System

Posted: Tue May 28, 2013 9:48 am
by bugwubber
Arthur Liew wrote:Hi Bugwubber,
I launch it straight up,the nose cone is straight down after apogee.I am using a 1.5litre bottle for the rocket.
Ok so its flipping over but nosecone is staying on. Can you press the nosecone down with your hand and wedge it on to the bottle? If you can, you need to add some type of hard collar or rest to the bottle to prevent that. Don't think length is an issue.

Might try a launch with a couple fo air flaps taped to the nosecone.

Bugwubber

Re: Deployment System

Posted: Tue May 28, 2013 9:53 am
by Arthur Liew
No,I can't press it down.The nosecone is very loose.

Re: Deployment System

Posted: Tue May 28, 2013 2:02 pm
by bugwubber
Couple more suggestions-

add 2 air flaps to the nosecone
try a piece of memory foam in the nosecone- the kind you can squeeze and then it slowly expands.
lay a small drogue chute over the top of the nosecone- tie it around the edges of the nosecone so it only has an inch of movement.
put the weight on your chute string so it can fall out separately from the nosecone when the rocket tips over

The deal is, you have two objects traveling at the same speed and being acted upon by gravity in the same way. The challenge is to find some differential that will cause the pieces to separate.

Re: Deployment System

Posted: Tue May 28, 2013 4:37 pm
by Tony
Try putting air flaps on the rocket itself, so that wind resistance will slow it down more than it slows the nosecone, in effect, pulling the rocket out of the nosecone and deploying the 'chute.

Re: Deployment System

Posted: Wed May 29, 2013 12:10 am
by Arthur Liew
How can I do a air flap?

Re: Deployment System

Posted: Wed May 29, 2013 12:51 am
by bugwubber
Arthur Liew wrote:How can I do a air flap?
.
To test the idea just tape a couple horizontally cut strips of a bottle to the nose cone, so that they stick out an inch or so. Then, if that doesn't work try putting them on the rocket body

Re: Deployment System

Posted: Wed May 29, 2013 8:29 pm
by bugwubber
Ok I had given up on NOaA but decided to give it a try. I'm still dialing it in but, the memory foam seems to be doing the trick.

In the nosecone, I've glued a tennis ball to the inside top of the nosecone. then, a piece of memory foam
Parachute and nosecone are tied to elastic cording
The nosecone has scallops cut out to match the pressure bottle's feet lobes.
A ring of hot melt glue was applied to the pressure bottle, tightly following the scalloped cutouts.

Without the foam, the nosecone stayed on to the ground.
With the foam, it appears to be coming off too early.

I think drag flaps on the nosecone will solve the problem.

Here's a video of it..(yes it is now stuck in those trees)
[youtube][/youtube]

Bugwubber

Re: Deployment System

Posted: Sat Jun 01, 2013 9:46 pm
by U.S. Water Rockets1
Arthur Liew wrote:No,I can't press it down.The nosecone is very loose.
Is the problem related to the vacuum created inside the nose due to the air rushing past the bottom edge of the nose as the rocket is launched? The effect can cause a small vacuum inside the nose and it will suck onto the top of the rocket because there is no way for air to get in. You can try putting something around the inside of the nose to give it an uneven surface that won't seal against to top of the rocket. Or, vent holes in the nose itself.