Polaron IV rocket with boosters

Water Rockets NSW

Moderator: Moderators

air.command
Astronaut
Astronaut
Posts: 1906
Joined: Mon May 14, 2007 11:18 am
Location: Sydney, Australia
Contact:

Polaron IV rocket with boosters

Postby air.command » Tue Feb 26, 2008 8:08 pm

We had a chance to fly a rocket this weekend at the NSWRA launch day with three drop away boosters. I guess the concept is not new and has been done numerous times before, but we wanted to try it for ourselves. We were happy that the boosters worked as expected and didn't send the rocket spinning out of control. You just never know if you will get unbalanced or misaligned thrust.

Here is an update from the launch day, including photos and video:

http://www.AirCommandRockets.com/day55.htm


Image

Some info about the configuration:
Main Stage:
Capacity 8L
Weight 928 grams
Nozzle: 7mm
Water: 2L + foam

Each booster:
Capacity: 2.1L
Weight: 130grams
Nozzle: 13mm
Water: 1L

The main stage fires at the same time as the boosters, and the combination of foam and small nozzle gives it good long foam trail. The boosters were needed to get the rocket up to speed as a 7mm nozzle does not produce enough thrust on takeoff for that rocket.

The entire rocket and boosters are held down only by the main stage nozzle. The nozzles of the boosters are not held down at all. This allows us to let go of only the main stage and they all go up at the same time. Because of the forces involved the Gardena release head is of the brass variety that uses ball bearings to hold the nozzle rather than the typical plastic tabs. We also machined up the main stage nozzle out of aluminium so it would not get deformed as much as plastic would against the ball bearings.

The booster retention mechanism is pretty simple. The main stage has small tubes (made from ball point pens) glued to the body, and the boosters have opposing pins (made from coat hanger wire) glued to them and they go into the tubes. Because the boosters produce more thrust than the main stage they stay in place during the boost phase, and just slide out when they stop producing thrust. They are light enough to return back to earth without any recovery system.

We will post full details of the launcher and rocket in the next update.
Crop Circles: ... just a bunch of guys looking for their rockets ....

astroboy
Astronaut
Astronaut
Posts: 1545
Joined: Wed Apr 25, 2007 5:06 pm
Location: Pandemonium, 9th Circle of the Abyss

Postby astroboy » Tue Feb 26, 2008 8:19 pm

Very, very cool!! That stuff goes totally against what most people believe......water rockets are simple and not challenging. You prove time and time again this is not the case.Great work! :)
Satans stooge.

Kryten
Astronaut
Astronaut
Posts: 1972
Joined: Wed Oct 24, 2007 11:06 am
Location: Sydney

Postby Kryten » Wed Feb 27, 2008 10:11 am

It's even more impressive to see it in person (as I have been fortunate to do so).
Fantastic work as usual.
(What's next? :shock: )
"Pub, ah yes. A meeting place where people attempt to achieve advanced states of mental incompetence by the repeated consumption of fermented vegetable drinks" (“Timeslides”)

air.command
Astronaut
Astronaut
Posts: 1906
Joined: Mon May 14, 2007 11:18 am
Location: Sydney, Australia
Contact:

Postby air.command » Wed Feb 27, 2008 10:46 am

Thanks guys. For me most launches are more of a relief in that the rocket doesn't explode on the launch pad or that it doesn't go spinning out of control. If the parachute opens then that is a bonus. But I guess that's what keeps the hobby interesting for us.

Kryten wrote:(What's next? :shock: )


We would like to launch our big two stager but, because of the weight issue (more than 1500grams) , and the fact it has an aluminium tube running through the middle of it, will likely put it into the HPR category and hence would not be allowed at the launch.

Otherwise in the near future we will launch the rocket we just flew a few more times at least, with a longer main stage, bigger boosters, and more pressure. We hope to shave about 20% weight off it too so that should give it a bit more performance.

Eventually we should try a water rocket booster with a pyro second stage no? :D
Crop Circles: ... just a bunch of guys looking for their rockets ....

astroboy
Astronaut
Astronaut
Posts: 1545
Joined: Wed Apr 25, 2007 5:06 pm
Location: Pandemonium, 9th Circle of the Abyss

Postby astroboy » Wed Feb 27, 2008 4:21 pm

Have you done any work with fluoro light protector tube?
Satans stooge.

air.command
Astronaut
Astronaut
Posts: 1906
Joined: Mon May 14, 2007 11:18 am
Location: Sydney, Australia
Contact:

Postby air.command » Wed Feb 27, 2008 5:34 pm

We haven't built any FTC rockets yet, although we did buy 4 of the tubes about 6 months ago. The main problem is that they are so expensive. 4 six foot tubes cost $70. We eventually want to use them for upper stages, but that's at least another 6 months away.

So far reinforced FTC based rockets are the highest flying water rockets.
Crop Circles: ... just a bunch of guys looking for their rockets ....

astroboy
Astronaut
Astronaut
Posts: 1545
Joined: Wed Apr 25, 2007 5:06 pm
Location: Pandemonium, 9th Circle of the Abyss

Postby astroboy » Wed Feb 27, 2008 7:14 pm

If what I have is the same stuff, I can get 4 foot ones for $8 each. Might not be the same stuff though, I dont know.

Do they spiral wind them with carbon tow?
Satans stooge.

air.command
Astronaut
Astronaut
Posts: 1906
Joined: Mon May 14, 2007 11:18 am
Location: Sydney, Australia
Contact:

Re: Polaron IV rocket with boosters

Postby air.command » Tue Mar 11, 2008 10:19 pm

air.command wrote:We will post full details of the launcher and rocket in the next update.


We now have the full details of the launcher, rocket and booster retention mechanism available here:

http://www.AirCommandRockets.com/day56.htm

If you have a pair of red/blue 3D glasses you may want to get those out as well. 8)
Crop Circles: ... just a bunch of guys looking for their rockets ....

~RR~
Engineer
Engineer
Posts: 1127
Joined: Tue May 01, 2007 5:30 pm
Location: QLD

Postby ~RR~ » Wed Mar 12, 2008 6:42 am

I'll have to make the trip down to see this in action myself one day...
Awesome George 8) ...

nice touch with the 3D to, kids had a set of glasses on hand :lol:
Shane...
TRA # 11474

air.command
Astronaut
Astronaut
Posts: 1906
Joined: Mon May 14, 2007 11:18 am
Location: Sydney, Australia
Contact:

Postby air.command » Thu Mar 13, 2008 2:28 pm

The 3D photos are really easy to make. You just take a photo and then move over a little and take another.

We use a tripod with a little sliding piece of wood that the camera is attached to. This gives us the correct alignment of the images, and makes it easy to move the camera about 6.5cm (eye separation) between shots.

You can do it just holding it though.

We also use the camera's stitch assist mode not for stitching together but because it locks the exposure and white balance for the photos. It makes the two images more consistent.

We use the free AnaBuilder program to assemble them.
http://anabuilder.free.fr/welcomeEN.html
Crop Circles: ... just a bunch of guys looking for their rockets ....

air.command
Astronaut
Astronaut
Posts: 1906
Joined: Mon May 14, 2007 11:18 am
Location: Sydney, Australia
Contact:

Postby air.command » Thu Mar 13, 2008 2:31 pm

astroboy wrote:If what I have is the same stuff, I can get 4 foot ones for $8 each. Might not be the same stuff though, I dont know.

Do they spiral wind them with carbon tow?


Astro it does sound like the same stuff. I'm not sure how they apply the CF but I imagine a CF sock is the best. I do like your idea of integrating the nozzle construction though!
Crop Circles: ... just a bunch of guys looking for their rockets ....


Return to “Air Command Water Rockets”

Who is online

Users browsing this forum: No registered users and 1 guest