Steam Hammer ?

Steam pumps seem to manage OK.

Would you have to gear it 2:1 as you say you want to raise the weight on the power stroke so most steam engines are double acting but that may help if the dropping weight were used to carry it over TDC and BDC

Try Stewart Harts Dake engine. No flywheel required at all. He has included one but during the build he confirmed it would run without one

Stewart Hart Dake engine

Pete

2nd one down is what you need

Posts crossed, I don't see the need for a crank on a filing or sawing machine and like above shows TDC would be when piston is at one end of stroke, BDC at other

Edited By JasonB on 16/06/2020 10:40:54

How about a pendulum that swings right round into a complete circle.

We could call it a pendwheel

Neil

Final thought,

Various multi-cylinder designs work without flywheels, anything will rotate continuously if it doesn't have dead spots.

The real function of the flywheel is to smooth the motion, this is why water power was still preferred to steam for spinning yarn in the early days and also what led to the invention of the governor.

Mine and feed pumps have no need for smooth, constant delivery of power so don't have flywheels.

What about steam locomotives? They don't have flywheels but use the massive momentum of the whole machine to smooth their motion. There were some notoriously unbalanced locos that used to sway or hammer the tracks due to poor balance.

Much lighter steam cars had flywheels, as did road locomotives that usually had to function as stationary sources of power. Steam wag(g)ons were bigger and heavier and usually had multi-cylinder engines.

The real answer, I suspect, is that adding a reciprocating mass (a) creates challenges in tuning it to match different engine speeds and (b) requires a level of extra complexity that could be used to add a second set of cylinders.

Neil

Really final thought…

Early steam pumps, did use a reciprocating mass, in the form of a heavy beam.

Neil

So if you did want a crank and TDC/BDC this is how I saw the geared weights working.

The double acting piston would connect to a crank and then to a crankshaft. large gear on the crankshaft would drive smaller gear at 2:1 and weight suspended from smaller gear. on the two power strokes from 45deg to 135deg and 225 to 315 the weight would be lifted. Before the piston gets to TDC or BDC the weight will start to drop and by driving back through the gears will pull the crank over BDC & TDC.

Saw or file could be driven by a second crank off the shaft or linked to the piston one.

That's how I see it working but the saw/filer may jump about a bit as the weight goe sup and down

Edited By JasonB on 16/06/2020 10:55:49

As I said, that is a double acting cylinder with NO CRANK. Obviously such a mechanism works fine – the motion is generated linearly from the start – there is in fact no TDC or BDC – the motion changes direction when the appropriate valve is actuated.

If PGK drops the thought of a crank in his mechanism and uses a double acting cylinder, then , well, nothing to discuss..

Surely you dont want a reciprocating weight because it takes energy to slow it down, stop it and then reverse its direction at the end of each stroke? Sounds horribly low efficiency doesnt it, like Neil's beam engine?

Edited By Hopper on 16/06/2020 11:22:53

The 'free engine gassifier' from about the '80s used opposed pistons running against a sealed chamber ie using compressed gass to store the energy and then use it to power the compression stroke.

The governor was invented for regulating windmills long before Watt sneekily patented it and severely restricted the progression of the art of grinding flour as he did with the crank which held back steam engine development by a decade.

That is still a flywheel, all be it a very out of balance one. It's rotating not reciprocating. Hopper has most of the story with the energy required. the big isse is that a recoprocating mas stops. I horizontal all the inertial energy is wasted stopping it again. If vetical there is only potenial energy which can only be recovered on the way down.

in either case nergy is only stored for hlf the stroke.

Any egnge with a crankshaft has a flywheel – the crank. They only need a extra flywheel if the crank isn't big enough.

Robert G8RPI