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There's more to Putt-Putt than the obstacles

old man emu

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Red posted this over on the Funnies section: 784139432_zipperpuller.thumb.jpg.0afda350d66adc535cd4ba29a24832a3.jpg


Here's an old idea worth investigating. Why not use the principle of the putt-putt boat engine to power a people-carrying boat? The putt-putt engine has none of what we consider moving parts. It only requires a heat source to boil a relatively small amount of water, so the cost of generating heat might be a whole lot less than the cost associated with either an internal or external combustion engine they we are familiar with.


It's very hard to explain this idea in writing, so here's a video in which the operation of a putt-putt engine is described. 



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2 hours ago, facthunter said:

I don't know how well it would work scaled up. Nev

I suppose there must be some ratio between the volume of the boiler and the volume of the tubes.


In the video, the presenter said that the forward motion was the result of unbalanced Momentum. Probably technically incorrect as I would invoke Newton's Third Law (equal and opposite forces), but that's a moot point at this stage.


It's pretty obvious that this propulsion system is akin to a jet system, so to use this system to propel a small boat, like a tinny, you would have to know the value of the friction between the tinny's hull and the water to  get an idea of the minimum Thrust needed just to get the tinny moving.  The Coefficient of Friction is going to vary with hull design and, I think, the speed of the boat. But those are things to consider for a wider application of the method. First step is to see if a putt-putt engine could do it.


Here's a research paper on the subject. https://www.researchgate.net/publication/318000523_Factors_Influencing_Performance_of_a_Model_Steam_Engine_Putt-Putt_Boat

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One of those crackpot ideas was actually used. The torroidal tit engine.

The theory was that the cylinder of an engine had acircular depression in the top and in the depression there was a sharp spike pointing up to the cylinder head and it was well faired into the cylinder. The engine ran on soap bubbles with a goldfish in the carburettor. Air was sucked in and the goldfish blew a bubble which went into the descending dylinder, then the piston came up compressing the bubble. At TDC the torroidal tit burst the bubble forcing the cylinder down.

The design was modified slightly and became the AEC diesel engine which was used in London buses.

That was the story I was told when I was an apprentice working on AEC engines.

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I'm afraid the first video just left me confused - perhaps it's because the bloke isn't really good at explaining it all.


To acquire forward momentum, you must need to have an energy source, and expend energy to acquire that forward momentum.


The energy is coming from burning the oil in the candle - so why not simply burn the oil in a little combustion engine?


I guess the candle advantage is there's no moving parts, and no frictional losses, so the energy transfer level is improved over an IC engine.

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Casey is an old man who wants to be a teen
He goes to all the dances, and they call him cha-cha King
He cha-chas when the band is playin' rock 'n' roll
He tries to keep in time, but the beat leaves him cold

Because he's too pooped to pop, is too old-school
Hips gettin' weaker when he tries to do this stroll

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