Steam

Weird Harold wrote:

Tenshinai wrote:The monster in the picture would likely have great difficulties getting anywhere away from roads.

Nope, that's the ultimate off-road machine. The only thing better off-road than those "walking wheels" -- whatever they're properly called -- is a continuous belt/tread such as a snow-mobile or caterpillar tractor uses.

Are you refering to traction engines?

http://en.wikipedia.org/wiki/Traction_engine

Steambucket wrote:Are you refering to traction engines?

http://en.wikipedia.org/wiki/Traction_engine

Nope. One of the pictures of Big Lizzie shows a load of two traction engines as shown in your link.

Only one example from your link shows a tracked traction engine ( pic here ) such I referenced.

What I called "walking wheels" are like those pictured on Big Lizzie above, with three or more wide plates affixed to the rims to provide flotation on soft ground.

Weird Harold wrote:

Tenshinai wrote:The monster in the picture would likely have great difficulties getting anywhere away from roads.

Nope, that's the ultimate off-road machine. The only thing better off-road than those "walking wheels" -- whatever they're properly called -- is a continuous belt/tread such as a snow-mobile or caterpillar tractor uses.

Even a tracked vehicle that weighs too much wont be able to move a whole lot.

And they´re called dreadnaught wheels.

Big Lizzie was 46 ton unloaded and up to 127 ton loaded. Pulling at most 2 trailers.

The thing on the pic is roughly 5m high and 5m wide. ~22m long.
Even if you use absolut minimum of armour, that´s maybe 40 ton by itself.

To get a more useful, realistic level of armour, triple that total tonnage is more likely if still low.

Then, add to that 120 ton or so for the vehicle parts themselves.

Then comes machinery. Another 20 ton.

So at a wild guess, we have a vehicle at maybe 200 ton with useless armour level or 300 ton with something that can at least stop small cannonballs.

Do you have ANY idea of just how problematic it is to make something that heavy move, at all?

Then we have the rigid nature of the whole thing, good luck having it cross even half a meter bump in the road, much less go into real rough terrain.

And it´s quite possible that i´m being far too nice here and that we really need to double or triple the total tonnage.
The fancy "land battleship" of German WWII surrealism was meant to be much smaller but still weigh over 1000t.

No, the wheels are NOT the issue.

I dont think its true, i think its pretty stupid what Dic did. i just pointed out that if true, your equipment dies in like 5 minutes, so its useless, and kills your vehicle to boot.

Tenshinai wrote:

SYED wrote:does any one remember that back to the future movie involving stealing a train?
Doc created packages that burned so hot that the train went to record breaking speeds, so it that possible in real life, a fuel that burns so hot, it supercharges the engine.

Ugh...

No, it does NOT work that way.

You could run a steam engine on thermite and it wouldn´t matter, because more heat only means you heat up the boiler faster, the boiler pressure limit will be reached at the same time regardless what fuel you use or how how you can get it burning.

In theory you might be able to go from cold start to working pressure faster by applying more heat.

However, that will damage the firebox, the armature and may damage the boiler because of parts expanding too quickly.

There´s also the problem that any localised heat source of extreme level is going to burn through the floor of the firebox.

Spacekiwi wrote:If true though, note what happens after though. IIRC, the heat caused problems, such as the boiler cracking. considering they only rode for a short time, so a supercharger tha kills your vehicle isnt wanted.

Oh dear, 2 people thinking it could actually be true.

How far are they from a steam powered submarine like the nautillus? SUre they would need a better fuel than coal, and there would be limitations due to the lack of electronics. but it would be awesome.

Tenshinai wrote:And they´re called dreadnaught wheels.

Thanks.

Tenshinai wrote:Big Lizzie was 46 ton unloaded and up to 127 ton loaded. Pulling at most 2 trailers.

The thing on the pic is roughly 5m high and 5m wide. ~22m long.

More details about Big Lizzie:

Eventually Bottrill, in association with A. H. MacDonald & Co. of Richmond Melbourne, began producing steam and oil-based tractors fitted with his wheels.[10] The most famous was known as 'Big Lizzie' built in 1915[9] with a wheel diameter of 7' 2" (2.2m).[8] At 34 feet (10.4m) long and 45 tons (46 tonnes); with two dreadnought wheeled trailers, it was capable of carrying a total of 80 tons (81 Tonnes) and effectively making its own roads.

Tenshinai wrote:Even if you use absolut minimum of armour, that´s maybe 40 ton by itself.

I wasn't talking about a hypothetical armored version of Big Lizzie, I was talking about the real Big Lizzie "Effectively making its own roads."

Tenshinai wrote:The fancy "land battleship" of German WWII surrealism was meant to be much smaller but still weigh over 1000t.

There is a point of diminishing returns in tank design where no bridge or road can take the load and power to weight ratios approaches Zero. That doesn't necessarily make steam tanks, or H G Wells "land dreadnaughts," impossible.

Tenshinai wrote:No, the wheels are NOT the issue.

They are however, part of the issue. Steam trucks, not to mention tanks, are going to be heavy and heavy vehicles require a lot of flotation in the suspension. A continuous track provides that flotation in modern tanks because they provide more flotation than dreadnaught wheels with less weight.

Weird Harold wrote:

Tenshinai wrote:And they´re called dreadnaught wheels.

Thanks.

Tenshinai wrote:Big Lizzie was 46 ton unloaded and up to 127 ton loaded. Pulling at most 2 trailers.

The thing on the pic is roughly 5m high and 5m wide. ~22m long.

More details about Big Lizzie:

Eventually Bottrill, in association with A. H. MacDonald & Co. of Richmond Melbourne, began producing steam and oil-based tractors fitted with his wheels.[10] The most famous was known as 'Big Lizzie' built in 1915[9] with a wheel diameter of 7' 2" (2.2m).[8] At 34 feet (10.4m) long and 45 tons (46 tonnes); with two dreadnought wheeled trailers, it was capable of carrying a total of 80 tons (81 Tonnes) and effectively making its own roads.

Tenshinai wrote:Even if you use absolut minimum of armour, that´s maybe 40 ton by itself.

I wasn't talking about a hypothetical armored version of Big Lizzie, I was talking about the real Big Lizzie "Effectively making its own roads."

Tenshinai wrote:The fancy "land battleship" of German WWII surrealism was meant to be much smaller but still weigh over 1000t.

There is a point of diminishing returns in tank design where no bridge or road can take the load and power to weight ratios approaches Zero. That doesn't necessarily make steam tanks, or H G Wells "land dreadnaughts," impossible.

Tenshinai wrote:No, the wheels are NOT the issue.

They are however, part of the issue. Steam trucks, not to mention tanks, are going to be heavy and heavy vehicles require a lot of flotation in the suspension. A continuous track provides that flotation in modern tanks because they provide more flotation than dreadnaught wheels with less weight.

Steam trucks weigh the same as regular trucks, you just trade off half a ton for a heavier engine and boiler. As for flotation, the tires on drawn vehicles are narrow (2") so a wider tread (pneumatic rubber for preference) will actually provide a much lower rolling resistance and less damage to the roads at a much higher gross weight. (English roads got so bad that horse drawn wagons had to have 18" wide wheels fitted in the 1800's - this lead to a road paving exercise from the government)
Tanks (and caterpillar tracked vehicles in general) have a much lower ground force (but higher traction due to higher contact area) than either, hence their better off road characteristics. (Dreadnaught wheels led directly caterpillar tracks but are easier to build (less finicky machining)).
BTW Big Lizzie is very heavily built, it is almost twice the weight of a WWI tank empty (42 tons vs 28 tons), moved at 1/10 the speed (1 mile per hour) and its 1/2" to 1" steel plate chassis would be bullet proof to small arms fire (better if the mild steel was replaced with manganese steel) (she also carried 6 months of fuel in the chassis so its effectively a big fuel tank as are its trailers).
https://www.youtube.com/watch?v=0g3BGVXVUk8

If you want to look at steam powered caterpillar tractors I might suggest:
http://en.wikipedia.org/wiki/File:Rusto ... _model.JPG
http://en.wikipedia.org/wiki/File:Rober ... ractor.jpg
http://hornsbycrawler.org/
http://en.wikipedia.org/wiki/Continuous_track


This presents the possibility of tracked supply vehicles and engineer support vehicles (i.e. Bulldozers)if not tracked tanks (but it would be a brave infantry man who would stand in a firing line with a musket with an armored steam engine coming at him). Two of them with a wire rope or anchor chain between them would see to most Napoleonic military formations (and forests).

AirTech wrote:Steam trucks weigh the same as regular trucks, you just trade off half a ton for a heavier engine and boiler. As for flotation, the tires on drawn vehicles are narrow (2") so a wider tread (pneumatic rubber for preference) will actually provide a much lower rolling resistance and less damage to the roads at a much higher gross weight.

Perhaps the first land use of steam-power would best be applied to replacing Dragons during winter. I'm not sure how big or heavy Dragon Wagons are, but "one dragon-power" steam tractors should be possible in not much more space than one dragon.

Just what sort of suspension and tractive mode would be required I can't say. I don't think something on the scale of Big Lizzie would be required, but I'm sure something could be engineered. Some degree of off-road capability would definitely be desirable to counter road damage and campaigns where roads don't run.

There's a surprising variety of precursors to base designs on. https://www.youtube.com/watch?v=SV9vOHnXpT8 is 54 minutes but looks worth watching in full; just the first minute or two shows more operating steam trucks than I knew existed.

Steam trucks weigh the same as regular trucks, you just trade off half a ton for a heavier engine and boiler.

I wonder if RFC is going to include superheater tubes with the boilers, it would make them more efficient. But as far as weight, the steam plant would be a lot heavier if you were going for any kind of range. I think I posted earlier about it's not just the fuel but also the supply of water, otherwise they would have to stop every few miles to refill the boilers. Also with the spent steam exhaust added to the combustion box will create low pressure and draw the heat from the firebox through the boiler faster. At least that's how it works with the superheater tubes.

Steambucket wrote:

Steam trucks weigh the same as regular trucks, you just trade off half a ton for a heavier engine and boiler.

I wonder if RFC is going to include superheater tubes with the boilers, it would make them more efficient. But as far as weight, the steam plant would be a lot heavier if you were going for any kind of range. ...

In that video I linked above, the range for most of those trucks was around 30-50 miles before refueling and watering was required; Most carried an extra 200 Gal tanks for roading between shows. I got the impression that "milage" was about 2 Gal/Mi and 5-10 Lbs of coal, depending on speed.

I suspect that Charisian steam trucks/tractors will haul a "tender" and a dragon-wagon to supply army units in the field.