Pnewmohudralic Jet Machine Marklar 3




About: I am a physicist. I am a developer. I like to build musical instruments.

Jet powered machines always more interesting than regular vehicle. So I
decided to create fun toy, with jet engine.

You can make this, for playing with kids and explain them how jet powered machines move.

This jet tricycle have interesting jet engine, it nice demonstration of working jet engine, and, which as for me more important, it shows depends between speed, weight and energy. And first of all it's simple, fun and spectacular vehicle.

Before I made this vehicle, I had made few others. First was catamaran, based on two bottles with compressed air, and one bottle, with water. It was fun, but, I want higher speed. Also I had notice, when bottle with water almost empty, and water outcome speed increasing, and vehicle too.

Obviously, this happened because speed of reactive mixture bigger than speed of water.

Also, I had made only pneumatic jet engine, and it's was not so effective.

Step 1: Some Theory

Main characteristic of jet it's impulse. Impulse it's weight multiplicities on speed. In my case, it's speed of flowing matter multiplicities on it's weight.

Vehicle with water jet had big weight of working matter, but low speed of flow (maybe because of turbulence in tube). Vehicle with air had big speed of flow, but low weight. I found compromise.

What if we can combine the good sides of air and water?

Let’s mix up.

In mixing working matter has lower density, lower weight, but bigger than in air, and bigger flows speed.

We, me and my young assistant, measured time of engine work, it's 10 seconds. During this time engine loose almost 100 grams of working matter.

My final speed calculation on photo above. Theoretical speed is 28,8 kmph.

About calculation. I suppose that 2 litters of volume just go away, like in vacuum. If I need to calculate speed of flow base on pressure of gas then I need to use molecular kinetic theory. But, in my case it's only mechanic.

Step 2: Materials and Instruments

Materials is very recycled. Recyclier can't be.

- roller wheels (borrowed, I will place them back)

- plywood from broken bead

- two straps from some chair

- plastic bottle

- two 'presta' nipples from bicycle camera

- plastic file carrier

- chlorwinil pipe

- polyvinyl acetate glue

- little peace from broken antenna, you can use any little pipe

- superglue

- screws


- screw driver

- clamps

- hands

Step 3: Engine

My friend sad me, you need a 3d printer. But I sad, what I would do to
recycling materials?

So, I create little frame to combine coaxial outer and inner tube.

This frame, I build from plastic file carrier. I cut it, made 4 rectangle and glue it together with superglue. This carburetor frame must be not so big for placing into bottle.

I made two holes in frame, and placed there nipple, and pipe from antenna. Pipe from antenna must placed coaxial.

Frame I fix in bottles cork.

Pipe from antenna connected with chlorwinil pipe.

That nipples outer whole is our engine.

Step 4: Frame

I decided, that this vehicle had 3 wheels. Less wheels - less friction of
rolling. Wheels I borrowed from my roller skies, I will take them back.

Frame. Frame I build with wood from some old chair, which I found somewhere near recycle bean.

Front wheel I sat on plywood which I glued to the longitudinal bar. After that I made T-like frame. I connected wheels to frame with screws.

I glued peace of bottle holder to frame.

Step 5: Testing

Vehicle done. Experimental speed was 28.5 kmph. Calculated 28.8. I think
accuracy not bed.


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    13 Discussions


    Question 1 year ago on Step 1

    Hello, i cannot understand how specifically you designed air/water mixer (carburator) in order to make one myself. You have done a great machine!

    1 answer

    Answer 1 year ago

    Hi. Thanks for question.

    My carburettor is two coaxial (with same axis) tubes with different diameters, one inside other. Through bigger tube (actually, through aperture between tubes) goes air. Through smaller goes water. Air captures water, and they go together. It works more like spray nozzle.


    1 year ago

    My screen is too small so I can't tell for sure what you're doing. are you pumping air into a 2 litter bottle of soda with a just a little water in it? How much water do you put in the bottle? Thanks.

    2 replies

    Reply 1 year ago

    Thank you for comment. I pumped bottle to 7 atm with 100 grms of water. Engine works 10 seconds.


    Question 1 year ago on Step 3

    I like this idea very much. Your 'carburetor' is a very inventive idea. I think you are using a 2 liter bottle fueled with water and air pressure, like a water rocket - but used with wheels to travel on a road surface. I picture the outside tube blowing water and the inside tube blowing air taken by blue tube from above the water level inside the 2 liter bottle. This makes a blast of air / water mix to give better thrust or push and also allows less water to be in the bottle. (If the bottle is tilted up so the water will drain completely, then there will not be 'dead weight' slowing the acceleration. However the angle of the jet nozzle will need correction.) Have I captured the working idea that you invented? Thanks to a fellow "trash to treasure" enthusiast and inventor!!

    1 answer

    Answer 1 year ago

    Thanks for this question. You understand my idea wery deep. Angle of jet nozzle, I think, must correcting while moving. And, air blust, on first launch happent because of accseleration, water flow to beck of vehicle. And, of corse you can use my idia.


    Reply 1 year ago

    Thank you. I want to make marklar 5 with some automatic elements.


    1 year ago

    Now if I can just fit an upsized version to my 50 foot yacht I'll be off round the world

    1 reply

    Reply 1 year ago

    You know, if I would do some vehicle it's will be some with ground efecs vehicle. I mean, lets di this, but I think will be better if we'll do some defenetly new :)

    Penolopy Bulnick

    1 year ago

    That is a pretty impressive little car :)