Giant deathtrap: I want one! (also lions and tigers)
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Слава Україні! Героям слава! Слава Україні! Героям слава! Yeah I had been thinking along similar lines. The whole front truck is basically just a huge wrought iron combine harvester. The crew would have been terrified of going anywhere near it. Слава Україні! Героям слава! 
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Hey, it clicked why this thing was no good for general use. Adhesion was probably part of the problem, but the other was gearing.
The cylinders were only about the same size as the Adler's, which was normal for that time, and the boiler pressure was the same at a measly 50 psi, but it was expected to turn drivers more than twice the size of the Adler's. That's basically like trying to ride a bike uphill in top gear. It would have been very short on hauling power, even though it's theoretical top speed was very high, and would have been limited to total train weights around half of what an Adler could haul.
7 foot drivers became practical on the Firefly class, but they had higher boiler pressure by then (around 80 psi AFAICT) and that would produce a lot more grunt from the same cylinder size. To make the Hurricane work well with its 10 foot drivers, it would have needed a boiler pressure up around 100-120 psi. Those levels weren't seen until the mid-1850's.
Which is a heck of a difference. I just found that out, not having run the numbers before and just assuming it was a gearing problem. 
Mr. Brunel gave the following evidence relative to these 10ft. wheel engines before the Gauge Commissioners in 1845:
"Three engines were made for 10ft. The idea did not originate with me, but it was proposed by certain manufacturers, and although I expressed some fear of the feasibility of constructing 10ft. wheels, I thought it worth the trial.
They were made, and it so happened that the three engines to which they were applied totally failed in other respects, and the whole engine was cast aside.
*snipped stuff about the other two locos*
In the other engine (' Hurricane'), which was tried with a 10ft. wheel, the wheel worked very well, but accidental circumstances threw the engine out of use; the wheels got broken by an accident which would have broken any wheels, and no further attempt was made to use it."
Слава Україні! Героям слава! I have seen a few period films of logging operations and what I've seen is that on grade like you mention, the engines were generally placed at the rear pushing, rather than dragging. Or they would have a fore and aft arrangement with the tail pushing up until the crest was made, then the lead loco would take over. I've even seen static images of logging operations with the loco in the centre of the train with wagons ahead and behind. I always assumed it was a power issue that caused the arrangement, but after thinking about it, it had to be a traction issue.Gumboots wrote:OK, so Harrison gave the thing plenty of grunt. But I also know the axle loading was probably about the same as Adler, so it comes back to adhesion then. Hurricane had plenty of power for its day, but couldn't get it to the rails when hauling a heavy load. I'd guess it was worse uphill, since even good Garratts tend to slip a bit at the front if their front tank is empty and they are being pushed up a hard grade with a big load.
So, it's beginning to look like a bad day rather than engineering fiasco that took Hurricane out of service?Gumboots wrote:Edit: Hey Hurricane's cylinders are exactly the same size as the ones on the NSW T14 2-2-2. So in both cases there are 16x20 cylinders driving one axle, but the T14 had a boiler pressure of 120 psi (240% of Hurricane's) and ran on 73" drivers (61% of Hurricane's) meaning the T14's force at the rail was a smidgeon under 4 times what Hurricane could generate.
Offhand I don't know the axle loading on the T14, but going on the usual steam loco adhesion factor of 4 that would work out to around 12 tons. Which, in turn, means Hurricane should have been ok with a 3 ton axle loading on the drivers. Which it easily would have had. So meh.
Ok, so if Hurricane had plenty of grunt available, and had enough adhesion AFAICT, then it must have had other problems which rendered it uncompetitive with other options. My opinion of Harrison has gone up though. He obviously wasn't quite as silly as some people have assumed. There's a quote available from Brunel himself, but it doesn't give any details, except to say that Hurricane was scrapped after one of its wheels was broken in an accident.
Mr. Brunel gave the following evidence relative to these 10ft. wheel engines before the Gauge Commissioners in 1845:
"Three engines were made for 10ft. The idea did not originate with me, but it was proposed by certain manufacturers, and although I expressed some fear of the feasibility of constructing 10ft. wheels, I thought it worth the trial.
They were made, and it so happened that the three engines to which they were applied totally failed in other respects, and the whole engine was cast aside.
*snipped stuff about the other two locos*
In the other engine (' Hurricane'), which was tried with a 10ft. wheel, the wheel worked very well, but accidental circumstances threw the engine out of use; the wheels got broken by an accident which would have broken any wheels, and no further attempt was made to use it."
Слава Україні! Героям слава! That's the best thing about the technology of that era, it is simply elegant in its design. Each part informing you what it does and how it works with the next part. It's one of the reasons that it proliferated so rapidly and was often easily repaired by the local iron-monger. Unlike today's technology, which too often is beyond comprehension. Having had to replace the RAM in a few laptops, I feel safe saying laptops are assembled by pixies in magic land.Gumboots wrote:At a guess I'm thinking it was a combination of things. Purchase price and maintenance costs would have been higher than a 2-2-2, even assuming the same build quality. Stephenson & Co were experienced locomotive builders, but there weren't many of those around back then. The blokes who built Hurricane may not have been as good. There may have been basic materials/technology limitations too. I don't know who well those articulated steam pipes could have been sealed in 1838.
So it may have come down to Brunel weighing up the possible bang for his buck after that accident broke a wheel, and deciding he'd do better to spend his money on something else instead of debugging Hurricane.
Anyway, it's been interesting playing around with it. The one available profile drawing doesn't contain a lot of information, but once I started modelling the thing it became clear how it must have been built. Just starting from standard construction at the time, I quickly found that one component would determine the possibilities for another one. After a bit of head scratching and a few revisions, the thing pretty much starts building itself.
Which has taught me more stuff that will be useful for modelling anything.
Слава Україні! Героям слава! Mate, that's a show pony for the Blender forum, not a game mesh. The RT3 models generally use one basic square for each wheel, although some use multiple layers of squares (up to 8). They never go past 16 tris per wheel, and most are less than that. They look fine once they're spinning at a rate of knots. Especially in the middle of the night when it's raining. Слава Україні! Героям слава! 
Planets and adlers...... nuff said. Слава Україні! Героям слава! 
