.5cc Opposite Engine Drinking Straw is a tiny transparent engine made from carefully machined plastic parts. Attached to the intake side of the engine is a straw which you place into your drink of choice. At the exhaust side of the engine is an output straw which you place in your mouth and start sucking.
The suction of the straw is that which drives the engine, causing its little valves to open and close; its crank shaft to rotate and its pistons to fill with swirling liquid drawn from the drink, and be delivered via the exhaust.
It's called an Opposite Engine, because it's actually doing the exact opposite of that which an engine does ie instead of powering an action, it is being powered by the action. In this case the action is you (the user) sucking up a milk-shake or similar.
Note - careful maintenance is required by way of thorough flushing and cleaning. Multi-cylinder engines available for those with great lung capacity.-- xenzag, Dec 06 2012 ahem Milkshake_20Drilling_20Platform[edit: okay I take it back, it's not the same] [FlyingToaster, Dec 06 2012, last modified Dec 07 2012] I like it. It needs an attachable little plastic car that gets wound up over the course of a meal.-- Voice, Dec 06 2012 Actually, it *is* an engine...and it could do something, like mix the drink, or twirl a cocktail umbrella.
If the drink was high in alcohol, could it work like an internal combustion engine, with the piston made from liquid, and peizo ignition?-- Ling, Dec 06 2012 It could drive a small Stirling engine rigged up backwards, to act as a heat pump and cool down the drink.-- Wrongfellow, Dec 06 2012 All are possible variations on the principal of suction power. My first idea was for a Wankel Engine straw....but the more conventional version is preferred and got posted.-- xenzag, Dec 06 2012 going to need a mechanism to crank it up or it will stop in a place you can't start it again.-- WcW, Dec 06 2012 Is hydraulic lock going to be an issue? I'd mix martinis in mine, so we'd need a means of vermouth ratio control.-- normzone, Dec 06 2012 You are not supposed to use your lungs to slurp drinks! It's throat and mouth muscles for sucking but I don't know what they're called.-- pocmloc, Dec 06 2012 the camshaft will need to be 2 stroke and would (by logic) have poppit valves rather than pressure sealing exhaust valves. if you wanted the tiny camshaft it's going to add a lot of friction.-- WcW, Dec 06 2012 <polite cough> <link>-- FlyingToaster, Dec 06 2012 Just thinking out loud here, but I think it'd have to be at least 4 cylinder, actually 8, in order for the suction to continuously drive the engine. While the exhaust valve is closed, you get "dead head" on your suction.
Making it 8 or 12 cylinder isn't a bad thing...-- Custardguts, Dec 06 2012 //polite cough> <link>// ahem - different idea.....-- xenzag, Dec 06 2012 <dry cough> "Pardon me"-- normzone, Dec 06 2012 <phlegmmy cough> It's not going to work.
The only vacuum engine/motor I can find that was ever used much was for windshield wipers on OLD Ford cars, and that wasn't a piston engine shape.
You are going to have trouble pulling much of a vacuum. The lowest PSI air engine I can find needs 1 PSI, and it is some weird rotary thing that is *bragging* about the fact they only need 1PSI to start. You might be able to suck that thing around, but no other engine shape is likely to work.-- baconbrain, Dec 07 2012 [Insert joke about ex-girlfriends, golf balls and 9ft lengths of hose]...-- Custardguts, Dec 07 2012 //<phlegmmy cough> It's not going to work.// ha! squeeky dry cough.... of course it will work. It's a tiny engine, that's basically not much more than a flow through for the liquid which drives the reciprocation of its pistons, crank and valves. There is minimal compression, and minimal resistance, and of course being the halfbakery, it might just work.-- xenzag, Dec 07 2012 <hacking cough> okay, okay, it's not the same idea, but it sure ain't gonna work on MickeyD's caragheenan-based beverages.
based on a square-stroke 4cyl engine with one intake valve open at any given time, that's about half a pound force to overcome friction... so that should be enough to overcome the friction of the engine. [+]
But, unless you have a working flywheel you'll need to overlap the intake-valves opening so a 2-stroke with a minimum of 3 cylinders should get the job done.
Can we run one of the cylinders on alcohol to power the others ?-- FlyingToaster, Dec 07 2012 A fly-wheel is ok, but no power source other than the suction of the person, otherwise it becomes too easy to realise.-- xenzag, Dec 07 2012 If you add a flywheel, will it act as a pump if the drinker stops sucking while the flywheel is spinning?-- Wrongfellow, Dec 08 2012 [Wrongfellow], I think that depends on the design. My petrol truck engine acts as a brake when I let off the gas, but diesels don't.-- baconbrain, Dec 08 2012 It's not the square-cube law, but the surface area of a piston goes down a lot faster than the circumference does. I needed 1/4 the area to get 1/2 the circumference. Which is to say that the smaller a piston is, the more drag it will have from the piston rings.
The smallest running V-8 engine I found was at least the size of the guy's two fists. There's a running Wankel rotor about the diameter of an American penny.
There are paddle-wheels in desk toys that run off the difference in density between oil and water. So there's a low-pressure engine of sorts.-- baconbrain, Dec 08 2012 random, halfbakery