100MPH Water Rocket

Water rockets are just for kids right? Wrong!
This is no ordinary bottle rocket. With a custom launch pad, this rocket can store pressure for a timely release, and reach over 100 miles per hour!
Something that I only cover briefly in this video is the water rocket simulation program I wrote. This finds the optimal amount of water to put in a bottle rocket to achieve maximum speed and altitude for a given set of initial conditions. The results from this simulation are often unexpected... And if enough people ask, I will release a version online.
Sadly, this will be the last video on this channel for a while as I have to go back to university and earn my engineering degree. But that does not mean this channel won't have new videos again! Hit SUBSCRIBE to bring back The Dodgy Engineer sooner!
Here is a link to the water rocket optimisation code: github.com/sjw269/water-rocket
Stay dodgy!
#waterrocket #fastbottlerocket #giantwaterrocket

[@timarbatis640]

Really interested in how you made the simulation in python. The math and libraries. would love to see a video on it :D Good Job!

[@TheDodgyEngineer]

The only libraries I used were math and matplotlib, then it's just a matter of knowing the physics behind compressible flows, and a numerical sim can be made quickly (it took me an afternoon)

[@theodorgreisdal8974]

@@TheDodgyEngineer I'm doing an examproject about water rockets. I would very much like if you could get me some advice to find the optimal water amount by using Excel? It would be very helpful.

[@TheDodgyEngineer]

@@theodorgreisdal8974 Do the maths! Using a numerical method, work out the pressure at each time, use Bernuolli's principle to find the water jet velocity, use this to find the change in mass and volume of air in the bottle, next use the SUVAT equations to calculate the altitude and speed gain, then repeat for each timestep. Hope this helps!

[@btrocketry3736]

Should've added a bit of dishwashing liquid to the water

[@romane.67]

1:1 like to view ratio

[@romane.67]

also, I think the reason your choked flow water version didn't perform as well is that you reduced the thrust of the rocket(thrust is a function of the pressure differential and cross-sectional area) a higher fraction of thrust was being dedicated to fighting gravity reducing its acceleration and the stabilizing effect of the fins. you could try to increase the area of the outlet to get a higher top speed but that would be more like a pressure bomb instead of a rocket and may decrease how high it can go. you probably already knew this I'm just throwing speculation around.

[@TheDodgyEngineer]

My reasoning was more along a reversibility argument than actually thinking about the forces at play. The slower (and more stably) the water is pushed out of the rocket, the more efficiently work is done on the water. I didn't think about this too hard though, just a speculation really!

[@yeahx32p69]

hi man. Nice video. Can you share the code that you used for this rocket? Would be very helpful.

[@TheDodgyEngineer]

Hi, if you want the code send me an email and I'll send it to you

[@yeahx32p69]

@@TheDodgyEngineer Also. Why use coding when you can do it in excel?

[@TheDodgyEngineer]

@@yeahx32p69 Because I have done stuff like this before in excel and wanted to improve my python skills instead!

[@Leon-pu2lo]

Man really likes to say "in theory"

[@jmstudios457]

specific inpulse of water?

[@TheDodgyEngineer]

As an estimate, probably around 3, so about 100x worse than a decent liquid rocket engine

[@madhavgarg3804]

can that code be provided?

[@TheDodgyEngineer]

Here you go: github.com/sjw269/water-rocket

[@haikalvlog3288]

Bapak akak tingkatan 5 atau universiti tentera tu yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee hebatnya dah lah kaya

[@haikalvlog3288]

Ayah tolong rampas senjata api dekat budak menyampah tu woooooooooooooooooouuuuuuuuuuuuuuhhhhhhhhhh hebatnya akak tingkatan 5 atau universiti dahlah hari jadi time raya Aidilfitri

[@arro_rockets]

Noice