Launch Day – WRA Speed Record Attempt

Launch Day Preparation

After our latest car updates, camera and marker developments we were  finally ready to have a shot at a WRA Dragster record. We decided to try for the speed record first.

For a submission to qualify we need to meet the rules as layed out at

http://www.wra2.org/WRA2_Dragster_Rules.php

We prepared the car with two onboard cameras, one looking forward and one looking sideways. We also prepared our coloured cups to place on the 10m road markers so that it will be easier see the car pass the road markers.

MD80 Camera mount behind the front wheel

MD80 Rear Mounted Camera

We also decided for this launch day to use twitter to provide live updates from the launch day. We setup and tested a twitter client on our iphone and it worked well. Twitter updates are appearing on

http://twitter.com/toddhampson


Launch Day

We arrived at the launch site at approx 2:30pm and setup the launcher and the cage, at this point we realized we had forgotten our two normal camera to capture the run, so we decided just to use the iphone video camera and ty to hold it as smooth as possible.

We then measured out the course with our 50m tape measure and marked every 10 metres with a solid chalk line across the road. From the northern end we then marked the 45.7m mark with a dashed line. We then put the red cups every 10m, the blue cups every 50m and the green cup at the 45.7m mark.

We did some twitter updates, then turned on the two car cameras, turned on the electronics for steering, filled the car with water and bubble bath and locked it in on the launch rail inside the cage. Heres how our launch went

 

Results

We were happy that all of the videos were ok. We used VirtualDub to calculate the time it took for the car to reach the 150ft marker. To do this we used the side looking camera and went through the video file until we found the first frame where the car launched, this woudl be  our starting time. Virtualdub works out what type of file it is and how many frames per second the camera captured. For the MD80’s  each frame was 0.032 seconds.

We then went through the video file frame by frame until we could see the coloured cups in the frame. We then took the used the time from virtualdub for that marker when we saw the white line and the cup one frame past the centre of the frame of the camera. We listed the time to pass each marker then calculated the following

– Relative time to pass each marker putting the first frame as 0 seconds
– Time to move from one marker to the next
– Time to reach the 150ft marker
– Average Velocity at each marker
– Instantaneous Velocity at each marker

This information is available in a spreadsheet for each run   Dragster Speed Record Attempt

The results were

Speed record
Time
First Run 4.94
Second Run 5.32
Average 5.13
Distance
First Run 122m
Second Run 100.5m
Average 111.25m

 

Here are some graphs of the cars velocity as it made its way down the course

Run 1 - Velocity Graph

Run 2 - Velocity Graph

We think we have done enough to get the Dragster Speed Record with these runs. We  will submit the video and spreadsheet to WRA for peer review and hope that we get it accepted :)

Tags: ,

This entry was posted on Saturday, April 9th, 2011 at 11:32 pm and is filed under Launch Days. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

 
 

Comments are closed.