Trike With Water-Rocket Engine

Many of us made soda bottle rockets for science class. Some of us didn’t have that opportunity, and made them in the backyard because that’s what cool kids do. Water rockets work on the premise that if water is evacuated from one side of a container, the container will accelerate away from the evacuation point. Usually, this takes the form of a 2-liter bottle, a tire pump and some cardboard fins. [François Gissy] modified the design but not the principle for his water trike which reached 261 kph or 162mph.

Parts for the trike won’t be found in the average kitchen but many of them could be found in a motorcycle shop, except for the carbon fiber wrapped water tank. There wasn’t a throttle on this rocket, the clutch lever was modified to simply open the valve and let the rider hold on until the water ran out. The front brake seemed to be intact, thank goodness.

Powering vehicles in unconventional ways is always a treat to watch and [François Gissy]’s camera-studded trike is no exception. If you like your water rockets pointed skyward, check out this launch pad for STEM students and their water rockets. Of course, [Colin Furze] gets a shout-out for his jet-powered go-kart.

Thank you, [Itay], for the tip.

32 thoughts on “Trike With Water-Rocket Engine

  1. I’m surprised he is able to hold the handlebars at 5G. Say he weighs 150 lbs — at max acceleration he feels as if it is 750 lbs. Granted, the max only lasts a moment, but that moment is long enough to lose your grip.

    1. I think I saw straps below the handlebars to keep the rider in place. They didn’t seem to tense up so maybe he has a crazy-strong grip. He had some earlier tests so he knew what to expect.

      1. Not only would I have a crazy strong grip if I were riding this thing, it would take 3 people to help me let go once the ride was over, ha ha. Possibly a change of shorts might be in order as well.

  2. It’s difficult to tell from the video, but this is most likely a steam rocket, not a traditional water rocket. A water rocket will leave a visible wet spray that will wet the ground behind the rocket and cover the camera lenses behind the rocket with water droplets. None of that is apparent in the video, and the vapor coming from the rocket seems to dissipate like steam would. Not to take away from this amazing feat, just pointing out that this is not the same as a water rocket because a steam rocket undergoes a phase change which imparts extra energy to the thrust, and because steam is gaseous water, it is compressible and can use a C/D nozzle for additional thrust.

  3. This is amazing ! congratulations to this guy. I do not understand why is he sitting upright position, I am surprised. If he is looking to brake a record, he should lay down above the tank as much as he can , in that position I have no doubt he will go faster than 300 km/h ! His body in that position is a pure aerodinamic brake. I understand that this is probably the beginning and he must be testing also the dirigibility of his waterrocket trike.

  4. At first I was trying to figure out how the water reached the nozzle after the tank was less than half-full, then I realized that the thing’s acceleration was providing ullage. It is a spectacular build. There will still be a bit of water in the tank after a run though, because even at 5g in 1g gravity there’s a bit that won’t reach the nozzle. But really not a lot considering the freaking huge size of the tank.

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