Highspeed Analysis

[Brian]

I thought you guys might be interested in these graphs that I have calculated.

Just shows how fast they can get!

untitled2.JPG (59.85 KiB) Viewed 67 times

Frames
1: Accelerating on launch tube (shows how useful a launch tube is)
2: A constant increase in velocity along launch tube
3: Less water = More thrust
4: Probably a bit too much water
5: Accelerating with air only
6: Reaching peak velocity (420kph) and acceleration (3793m/s^2 or 387g)
7: Accelerating less
8: Almost a constant velocity, almost out of pressure

Heres the photos I analysed.

120fps

Copy of Water Rocket (337) numbered.JPG (276.19 KiB) Viewed 67 times

[Spaceman Spiff]

I thought you guys might be interested in these graphs that I have calculated.

untitled2.JPG

Frames
1: Accelerating on launch tube (shows how useful a launch tube is)
2: A constant increase in velocity along launch tube
3: Less water = More thrust
4: Probably a bit too much water
5: Accelerating with air only
6: Reaching peak velocity (420kph) and acceleration (3793m/s^2 or 387g)
7: Accelerating less
8: Almost a constant velocity, almost out of pressure

Heres the photos I analysed.

Copy of Water Rocket (337) numbered.JPG

That's pretty interesting data. How were you able to do those calculations from just the pictures? Did you use a reference object and take measurements based on how far the rocket moved in a given unit of time (in this case 1/120 seconds??)

[Brian]

Correct, I measured an object in the pictures, then the object on screen, then measured the distance the rocket traveled. I made an Excel Spreadsheet to calculate the rest. It can be downloaded from my new website http://ascenderwaterrockets.weebly.com/highspeed.html
I compared a 1.25L rocket with a 22mm nozzle and a wooden recovery system and camera module to a 1.75L rocket with 30mm nozzle and same payload and the 1.25L was faster
Im thinking the 30mm nozzle is too for this size bottle.

[U.S. Water Rockets1]

Correct, I measured an object in the pictures, then the object on screen, then measured the distance the rocket traveled. I made an Excel Spreadsheet to calculate the rest. It can be downloaded from my new website http://ascenderwaterrockets.weebly.com/highspeed.html
I compared a 1.25L rocket with a 22mm nozzle and a wooden recovery system and camera module to a 1.75L rocket with 30mm nozzle and same payload and the 1.25L was faster
Im thinking the 30mm nozzle is too for this size bottle.

What kind of camera did you use that does 120FPS?

[Brian]

Ricoh CX1, a small point and shoot camera with the ability to do a 120fps in a 1 second burst. Only 640x480 but still looks awsome.

[Spaceman Spiff]

Correct, I measured an object in the pictures, then the object on screen, then measured the distance the rocket traveled. I made an Excel Spreadsheet to calculate the rest. It can be downloaded from my new website http://ascenderwaterrockets.weebly.com/highspeed.html
I compared a 1.25L rocket with a 22mm nozzle and a wooden recovery system and camera module to a 1.75L rocket with 30mm nozzle and same payload and the 1.25L was faster
Im thinking the 30mm nozzle is too for this size bottle.

Excellent photo analysis! You have done a masterful job. I was wondering if you did that for your own purposes or if you did it for a school project of some type. If it was for school then I also commend you on your creative application of water rockets!

[Brian]

I first started wondering how fast my rockets were going, so I started analysing the highspeeds I was taking. Then instead of doing the calculations every time, I put the equations into an Excel Spreadsheet + it also gave me neat graphs.
I wish I had such a school project, but I just hope this may be usful to someone.

[U.S. Water Rockets1]

Ricoh CX1, a small point and shoot camera with the ability to do a 120fps in a 1 second burst. Only 640x480 but still looks awsome.

Ok. Thanks for clearing that up for us!