Increase Chassis Ground Clearance

We realised that the chassis of the car is scraping on the ground more than it was previously. The cable ties that hold the bottles to the chassis show quite a bit of wear due to the scraping. All the scraping is slowing the car down and reducing the distance the car will travel.

The scraping is probably due to a couple of things

  • the chassis being wet repeatedly and becoming more flexible
  • the long span between the front and rear wheels

When the  approx 2kg of water is added the middle of the chassis will touch the ground. We have a design for a lighter and stiffer chassis but decided to just modify this one slightly so we could submit a record attempt before we rebuild a new chassis.

The simplest way we came up with was just raising the rear of the car slightly . We achieved this by flipping over the L brackets that hold on the rear wheels and putting them ontop of the chassis rather than under it. This raised the rear by about 2cm and the lowest point by about 1cm. Here is a pic of the car with the rear raised.

The additional clearance of the chassis is visible in this wide angle shot

As the rear is now higher a section between the rear wheels had to be cutout to allow the launcher hose to connect to the nozzle. Also the screws used to attach the car to the guide rail had to be adjusted to slide correctly in the rail.

Posted by on February 12th, 2011 Comments Off

Optimized Mobile Access for HHWRSA

We have noticed there are a number of users accessing the site via a mobile phone. We also are using the  iphone more and more to do work on the website. So we thought we would optimize the mobile experience for the mobile users.

The website will now detect if a user is  accessing the site from a mobile device and show a new mobile optimsed version of the website to them. All the content is still there, its just easier to access and navigate for mobile users. If you are not using a mobile device you will see the normal website.

Here is what it looks like on an iphone

Main screen at the top showing recent posts

Bottom of the page showing the sidebar

Hopefully this will encourage more users to access the site via mobile devices :)

Posted by on February 6th, 2011 Comments Off

Twitter Feed and Panoramic Pictures

We have added a Twitter Feed to the website that is available in the right sidebar. This will allow us to post updates in realtime from launch days. To see our updates you can watch on the website and keep refreshing it, or  follow us directly on Twitter at the address below.

http://twitter.com/#!/toddhampson

We have been trying out the Twitter Client on the iphone which is working well.

We have also tried a panoramic photo  app (called autostitch) that stitches multiple pictures together into a single panoramic picture, all on the iphone.

We will be able to send out live updates from our upcoming record attempt as well as pictures as links to the twitter posts.

Posted by on February 5th, 2011 Comments Off

Launch Cage Test Day

We were fairly keen to try out the new launch cage so even though it was 33 degrees C (50 degrees C on the asphalt) last Sunday, we ventured out to our local launch  site to test the water rocket car with the new launch cage at launch pressures.

The water rocket car had the reinforced triple stack of bottles attached, which have been tested to 180psi. We also had the upgraded launcher using the high pressure hose, both of which hadn’t been run on the car before.

We were also trying out the new MD80 Camera which is a light camera mounted to the water rocket car.

The aim of the test day was to see how the car would launch out of the cage, if it was sticking in the guide rail or not launching straight. Here is the video of the launch day.

Results
Its not shown on the videos, but we did do a 60pis test and an 80 psi test before doing the 120 psi & 125psi tests. The 60psi and 80psi tests worked fine so we increased the pressure up to launch pressures. We didn’t include the video of these launches as they were not really all that  spectacular :)

We were pretty happy with the results of the cage test. The car on both high pressure launches is leaving the cage straight and there doesn’t appear to be any major loss of speed due to friction using the guide rail. There doesn’t appear to be any recoil of the cage and launcher and the cage held together well on launch. Getting the cage to the launch site also worked well, only issue was some strangle looks we got on the way there ;)

The MD80 camera worked ok, but we still have a few teething issues to work through as the first run didn’t record, or most likely, the second video recorded over the first one. We will work on that and possibly download videos from the camera between runs using a laptop, just to be sure.

The car once it left the cage was turning left, this was most likely just a slightly sticking front wheel, the wheel bearings were not greased before this test as we were not going for distance, which would account for the minimal rolling distance as well as the left turn. This should be easily fixed.

Here are a couple of video images showing the water rocket car launching. One of these is now posted on the dragstrer competition page on www.wra2.org , the page is here

Launch 2 - 125psi, very clean exit form the launch cage

Launch 1 - 120psi, nice exhaust plume when leaving the cage

Posted by on February 2nd, 2011 Comments Off