Delta twin booster rocket

Tue Jul 26, 2011 2:04 pm by danb

Over the past three months i have been designing and experimenting constructing a twin boostered rocket ive named it after NASA's Delta rocket as it has the same design the rocket is still under construction im hoping for a launch in August theres only a few bits left to complete i have not measured its total capacity yet but i think it should be around the 7L mark the sustainer and boosters are made from 1L bottles the boosters have a 10mm nozzle and the sustainer has a 7mm nozzle this will be lauched at 120 psi with a water foam mix for the sustainer and water only for boosters i will update over the next month on how the rocket is developing.

Sat Jul 30, 2011 8:35 pm by U.S. Water Rockets1

That's a very impressive looking rocket! Please post a report of your launches because you are one of the few people with a dual booster design and there's very little examples available showing how these designs behave. It would be interesting to see how this performs compared to those people using 3 or 4 boosters. Do you think it will spin a lot or what?

Sun Jul 31, 2011 9:34 am by Tim Chen

danb wrote:Over the past three months i have been designing and experimenting constructing a twin boostered rocket ive named it after NASA's Delta rocket as it has the same design the rocket is still under construction im hoping for a launch in August theres only a few bits left to complete i have not measured its total capacity yet but i think it should be around the 7L mark the sustainer and boosters are made from 1L bottles the boosters have a 10mm nozzle and the sustainer has a 7mm nozzle this will be lauched at 120 psi with a water foam mix for the sustainer and water only for boosters i will update over the next month on how the rocket is developing.

That's a really cool looking rocket!

Can you explain what you used for the booster connection mechanism? It looks somewhat complicated. Thanks!

Sun Jul 31, 2011 4:41 pm by danb

many thanks for the encouraging comments i personally think it wont fly as well as a 3 or more booster rocket but we will have to see how i connect the boosters are not complicated i use the same idea as George from air command coat hanger wire and aluminium tubing check out his website it explains it more clearly as the rocket is nearly finished im hoping to launch it in 2 weeks time i will post up any news.

Sun Jul 31, 2011 7:07 pm by WRA2

danb wrote:many thanks for the encouraging comments i personally think it wont fly as well as a 3 or more booster rocket but we will have to see how i connect the boosters are not complicated i use the same idea as George from air command coat hanger wire and aluminium tubing check out his website it explains it more clearly as the rocket is nearly finished im hoping to launch it in 2 weeks time i will post up any news.

Nice job on your rocket but you might want to try and redesign the booster connections using non-metallic parts. Should your rocket explode the metal parts (especially the wire hangers) could become deadly projectiles. Also you could save weight too if you used a lightweight plastic in place of the metal. Metal components are not recommended on the pressurized portions of the rocket. :!:

Sun Jul 31, 2011 7:22 pm by Team Seneca

danb wrote:many thanks for the encouraging comments i personally think it wont fly as well as a 3 or more booster rocket but we will have to see how i connect the boosters are not complicated i use the same idea as George from air command coat hanger wire and aluminium tubing check out his website it explains it more clearly as the rocket is nearly finished im hoping to launch it in 2 weeks time i will post up any news.

Even after his rocket blew up and turned into a fragmentation IED that reduced his launcher to metal confetti, he still encourages people to build rockets using solid steel wire? I hope nobody gets hurt because it will be on his shoulders!

There are plenty of plastic bits that you can use to connect boosters. I urge you to reconsider the use of metal bits.

Mon Aug 01, 2011 12:34 am by Brian

How does your bosters recovery rystem work?
How are the parachutes held on?

Mon Aug 01, 2011 4:22 pm by danb

The main stage has a side deployment recovery system the parachutes on the boosters are held by 2 strips of pet which have a hinge then wire goes through the hinge which is connected to the main stage, when the boosters stop producing thrust they fall away from the sustainer which pulls the wire out of the hinge which releases the parchutes hope this helps. And to reply about the metallic parts on the booster i fully understand that they can be lethal projectiles but George has proved that plastic can not stand the force that the boosters puts on the sustainer i personally would not blame air command if it caused myself injury. can anyone share any ideas of plastic parts that can be used to connect the boosters?
Dan B

Tue Aug 02, 2011 12:29 pm by U.S. Water Rockets2

Coat hanger wire (or screws, rivets, brackets, etc.) can become dangerous shrapnel in an explosion. That is why it is against the rules in 99% of all water rocket copmpetitions. You would be hard pressed to find one that allows metal connected to the pressure vessel like this. Independent of that you are free to use anything you want if you are in control of the launch area and are responsible for any accidents. If you are being safe you can experiment with whatever you like.

Based on our own experiments we can assure you that hanger wire is simply too malleable for high pressure water rockets. You need something a lot stiffer. It would pull through the receptacles like taffy during a high pressure launch, unless you doubled or tripled it up or added multiple connection brackets to spread the load. This increases the chances for a snag or malfunction.

For the the size and pressure your rocket appears to be, we suggest using hardwood or fiberglass dowels for hooks and polycarbonate tube receptacles:

http://search2.hobby-lobby.com/psearch/ ... ls&x=0&y=0
http://www.grainger.com/Grainger/polyca ... alog/N-aa5

PVC pipe is also very effective for load bearing structures, and is super cheap and easy to work with.
http://www.grainger.com/Grainger/pvc-an ... a0Z1z13lqv

For a high pressure rocket (or high structural loads on a very large/heavy low-medium pressure rocket) you may decide to use carbon fiber rods and tubes.
http://www.hobby-lobby.com/carbon_fiber_402_ctg.htm

Every rocket is different and what works for one person doesn't make it the only solution (or the best one). We encourage people to take what has been done before and refine and improve it.