Welcome to the Water Rocket Forum, sponsored by The Water Rocket Achievement World Record Association.

Since our founding in 2003, we've become the largest, most sophisticated and ground breaking group supporting you, the serious water rocket flyer! Whether you are a beginner or an expert, the WRA2 has something for everyone.

A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.


Hello Everyone. It is that time of year again. Time to approve changes to the competition rules for the new year.

You Can vote at:
viewtopic.php?f=32&p=19486#p19486

Please take the time to vote. TH:

Val4 and booster prototype

Discussions about rockets, construction materials, adhesives, nozzles, nosecones and fin design.
Post Reply
User avatar
retrotec29
WRA2 Member
WRA2 Member
Posts: 23
Joined: Sat Jul 22, 2017 7:46 pm

Val4 and booster prototype

Post by retrotec29 » Thu Oct 19, 2017 11:51 am

After the success of Val3 I decided there was room for improvement. Val4 is 10g lighter and 40mm shorter than Val3. Volume has been increased to 1.5L. Several test flights on Val1 has also yielded a new nose cone design. With that much loss in length coupled with the new nose cone the drag coefficient should drop to the 0.05 to 0.06 range. Numbers look good to go 500+ feet. As I tinkered with the numbers and a couple sims in Open Rocket I realized if I could boost this version to 45-50 m/s something interesting would happen. I could almost double the altitude. So I began the work on a booster. The staging coupler is based on the Mark3 used by Air Command. I did tweak it a bit to shorten the length and shave a few grams. Everything on the booster is built for speed. Recovery deployment will all be internal. Shroud venting will have a blow away cover to keep the air frame smooth before staging. Capacity of the booster is 4L. Everything has been pressure tested to 120psi. Compete dry weight for booster and sustainer should be around 500g. Being the prototype I have already come up with some ideas to knock off another 10mm of length and 50g of weight off the final version. With the weather closing in testing may need to wait for spring but I will update as things progress.
900BC870-8D2D-45A1-BB9A-7964EBE29FA7.jpeg
You do not have the required permissions to view the files attached to this post.


No matter where you go, there you are. Buckaroo Banzai

User avatar
anachronist
WRA2 Member
WRA2 Member
Posts: 110
Joined: Sun May 07, 2017 2:18 pm

Re: Val4 and booster prototype

Post by anachronist » Sun Oct 29, 2017 2:38 am

Nice. Not enough for the class B record, but those rockets don't use soda bottles, which to me sort of takes the fun out of the challenge. I've advocated to WRA2 in the past to expand the competition rules to include more unreinforced bottle classes (see this thread). I hope to see something soon.



User avatar
retrotec29
WRA2 Member
WRA2 Member
Posts: 23
Joined: Sat Jul 22, 2017 7:46 pm

Re: Val4 and booster prototype

Post by retrotec29 » Wed Nov 01, 2017 7:04 pm

We’ll see on the class B record. There are still a lot of “if it works” in this project. If I can shave the weight by 50g. And if the prototype works 1100 feet is achievable. I may not have the weather to prove it until spring.


No matter where you go, there you are. Buckaroo Banzai

User avatar
retrotec29
WRA2 Member
WRA2 Member
Posts: 23
Joined: Sat Jul 22, 2017 7:46 pm

Re: Val4 and booster prototype

Post by retrotec29 » Wed Nov 01, 2017 7:04 pm

We’ll see on the class B record. There are still a lot of “if it works” in this project. If I can shave the weight by 50g. And if the prototype works 1100 feet is achievable. I may not have the weather to prove it until spring.


No matter where you go, there you are. Buckaroo Banzai

User avatar
retrotec29
WRA2 Member
WRA2 Member
Posts: 23
Joined: Sat Jul 22, 2017 7:46 pm

Re: Val4 and booster prototype

Post by retrotec29 » Sun Nov 26, 2017 11:07 am

The prototype booster is complete. Final dry weight of booster and sustainer is 530 grams. So the sub 500 gram target weight of the final version looks achievable. Numbers on the sustainers apogee look well over 900 feet without the addition of the staging event. The actual altitude of the staging has many variables so that part is a wait and see.
AC2F0CF1-F432-4611-B0C7-3514B6BE6AC0.jpeg
Latest challenge is the launcher. My current launcher works very well but is just to small.
421DCE91-9D5F-4DEA-A627-D03F731416C3.jpeg
So the plan will be to build a new launcher and double the size. No elevation adjustment but the center post will extend to the ground with a ball joint adjustable foot. That will give the tripod and additional point of contact and directly transfer the energy of the rocket to the ground. Plan B would be to use my small mid-high power launcher with an adapter mounted to the rail for the launch tube. Another tripod design this launcher also uses a direct contact point in the center.
FAF847A8-C6BA-4B19-A27B-D68E09EEA4A0.jpeg
You do not have the required permissions to view the files attached to this post.


No matter where you go, there you are. Buckaroo Banzai

Post Reply