I need some help

[Mikey_s]

Firstly... I'll have one of whatever Ciro is drinking!

then I'll add some fuel to the fire and say again) ... wouldn't a battery qualify as a chemical reaction!!

us chemists can be everso annoying!


Somehow you have to store energy, but (depending on what the rules say) if you were to use electricity from the national grid (or a power source external to the craft) boiling the water would give some serious thrust - the change in volume from liquid to vapour should be a good way to propel the craft.

hmmm ... and then I think, how about dry ice, that'd give you a means to create a pressure differential, a 'tank' of water, drop in a lump of dry ice and put the lid back on, and of you go...

The possibilities might not be endless, but there are cetainly several solutions.

[Crabbia]

sorry to bring up painful memories ciro
But Just one more time then i'll shut it...

Forza Azzuri. Siamo campioni del mondo!
there, i'm done.

ya u mentioned one draw back in my design in that the rubber band might release its energy too quickly fot the rotors or propelors in this case i guess.

So lets get big bore american on this the shall we...

Ciro, i donno if u might be able to help on this cuase ur pretty good at finding interesting novel inventions on the net, but a couple of years back, mitsubishi was working on a boat that had a magnetic propulsion engine. the kinda thing that the sub in 'the hunt for the Red October' had. apparently they got it right but scrapped it soon after for some reason, probable failur to find an adequate way to store allthe electrical power needed.

Okay, maybe its a bit more high tech jap than big bore american.

...but certainly not a ferrari solution... those are much more elegant! Repect to Rory Burne, Lord of all designers

[Crabbia]

oh crap i just realised, batteries again, and u might be right mikey... depending on how anal the ANASTCIBWEOA get when they meet next. If any one of max mosley's linegage are involved, we're screwed...

[Crabbia]

Just had a look around, it does work. here's a link if ur interested rafael...http://itotd.com/articles/500/magnetohy ... ropulsion/

I hope my efferts in this regard help to ease the pain of quaterfinal knockouts and the infamous all-european semifinals

[flynfrog]

sorry to bring up painful memories ciro
But Just one more time then i'll shut it...

Forza Azzuri. Siamo campioni del mondo!
there, i'm done.

ya u mentioned one draw back in my design in that the rubber band might release its energy too quickly fot the rotors or propelors in this case i guess.

So lets get big bore american on this the shall we...

Ciro, i donno if u might be able to help on this cuase ur pretty good at finding interesting novel inventions on the net, but a couple of years back, mitsubishi was working on a boat that had a magnetic propulsion engine. the kinda thing that the sub in 'the hunt for the Red October' had. apparently they got it right but scrapped it soon after for some reason, probable failur to find an adequate way to store allthe electrical power needed.

Okay, maybe its a bit more high tech jap than big bore american.

...but certainly not a ferrari solution... those are much more elegant! Repect to Rory Burne, Lord of all designers

a freind of mine is working on that right now it does work but it take massive amonts of energy at least his does but cool none the less

the co2 car may be on to something no chmical change only phase its being propeled out by the energy of of teh co2 gas expanding pushing on the water i think this is a flexi wing but if the rule book dosent say you cant do it

[wazojugs]

I have to build a small toy car for the fluid dynamics subject, the car must be moved by a water jet, we can´t use compressed air or chemical reactions, but we can use mechanical means to push the water to the outside of the water tank, anyone know where I can find anything which could help me with this work.

Thanks a lot

Jusr remember when they empty the tank after the race/run you don't have any remaining in the collector tank or you will be underweight. Groan

[flynfrog]

i just thought of something the dry ice is technicaly compresed gas too

what if you put the water into a ballon then wound it up some how so that the strechness of the ballon gives the propulsion

[MrT]

If the rules state "do not use compressed air" use another compressed gas, nitrogen for example.... all about finding the loopholes!

[Rafael de Oliveira]

Thanks a lot for the informations, but the rules are very specifics, I can´t use any kind of compressed gas, chemical reactions or any kind of device to increase the temperature of the water. I have only two possibilities, I can use only the pressure of the athmosphere (is this suficient to move the car ??) or use some kind of mechanical device to pull the water out of the tank with a little bit more pressure (I can use all tank water during the race). The distance of the race is 10 meters.

Thanks a lot

[flynfrog]

i would look at gravity feed and start working on a verry efficent propler to mount ot the axel it may

[Mikey_s]

dry ice is not compresed, but when it changes state it does change in volume (substantially). Gravity feed (with outriggers) is also still on. But once again you need some sort of energy storage device - you can't move the craft without energy. Rubber band would do it, or a spring and an impeller...

[Crabbia]

i got it wrong at first, i only realised now the car must run on the bottom of the tank, so kow i think, for sure, it must have a gavity feed like mikey says.

I'm thinking something like a long tube attached to the car. One end is a meter or so above the water level and the other end it attatched to the car and has a 90° bend and a reduced diameter so that the water jetted out of the end of the tube pushes the car forward.

This again may use up energy too quickly and hence be ineffecient so if that is the case you could run an impeller (like mikey suggests) at the exit of the water tube. This impeller could be attached to the axels of the wheels of the car and hence drive it forward. Its a long shot and lots of things to overcome but it might work.

Things that'll oviously have to be looked at:

Sticking the car to the ground so that there is enough taction,
Making sure the wheels themselves have enough grip on the bottom of the tank,
Hydrodynamic shape of the car and water column,
Drivetrain issues from impeller to wheels.

on sticking the car to the groung i'm thinking you could angle the jet slightly upwards so it the exiting water pushes the car forward and downward at the same time.

[flynfrog]

if it is at the bottom of the tank why not just drive it as a sub instead of a car then there is no worry about traction

[Ciro Pabón]

I do not know, but a gravity feed system does not compute: the energy stored is low for the weight of the structure you need to keep the tank 1 m over the floor. The nozzle speed would be low, too.

I would go with a mechanical driven pump that actuates directly on the wheels, not as a reaction jet.

Actually, I do not know what the water is for: you could simply attach the mechanical drive to the wheels and spare the effort of the tank, transmission and propeller construction.

[vyselegend]

That make me think to the boats that sail on the missisipi in America. They have those sorts of hydro wheels that can be found also on water mills. If the bottom of the water tank is linked to this kind of hydro-wheel, while this weel itself is on the same rigid axe as the car's wheels, it would make the car to go forward with the natural pression of the water tank emptying.

Then, you could add a spring on top of the tank (which should have the shape of a tube), with a tight push rod, so that it would act as a syringe as soon as the spring is released (so of course you need a manualy releasable clip to keep the spring compressed at the begining).