Anyway, one of the best known Chicago Turret Wagons was "Big John" (aka 6-7-3).
https://chicagoareafire.com/blog/2013/04/chicago-fd-turret-w...
https://chicagoareafire.com/blog/2013/04/chicago-fd-turret-w...
Not sure if CFD still maintain any Turret Wagons in contemporary times or not, but variations on the concept are still found, particularly in industrial fire departments that protect high hazard sites like oil refineries, certain chemical plants, etc.
Whereas a modern tanker truck can do 1,000 GPM for 2 or 3 minutes, but can do it immediately upon arriving onsite.
https://www.piercemfg.com/fire-trucks/tankers/bx-tanker
It's also relative to how fire-fighting has changed over time, modern buildings that are big enough to NEED the Big John are also much more fire-resistant (concrete instead of wood, etc).
I've often thought about that when there's a work crisis: If I'm the second on the scene, what can I do to support those fighting the fire right now, before jumping in.
As the engine drives in it drops a 3" hose along its path. Next is our big tender with 3000 gallons. It stops at the street and connects to the dropped hose to pump more water up to the engine.
The tender also has a drop tank -- think about a portable kids' wading pool but much larger and deeper. Shuttle tenders refill the drop tank while our big tender draws from it to continue supplying the engine.
We don't have fire hydrants, so this is the dance we have to do.
* It's very important to park the engine close to the fire but not too close. Ask me how I learned this.
I was a farm hand as a summer job to cover beer and books in my college years. We harvested wheat which carries a high fire risk. Most farms kept a tractor with a large plow hooked up so it could quickly encircle and contain any fires.
Pulling a 40’ wide plow is hard. Tractors can do it because they have huge engines that suck in huge amounts of oxygen.
Just like fires.
If you get a tractor too close to a fire it starves for oxygen and stalls out. The plow becomes an anchor. There’s just enough time to bail out before the tires catch fire. After a few minutes the whole thing is a pile of ash and melted steel.
1,000 isn't going to put out a house fire unless it's really small and not fully involved. The past two good structure fires we had took 20,000 and 60,000 to gallons respectively.
Rural properties I'm familiar with required a 3,000 gallon water tank with fire-connection far enough from the main structure as to be accessible.
But ask the fire department how they'd approach your house, and put the hydrant on that road; it might NOT be the road/driveway you normally come up!
Great! Now I'll have to see this quote over an image of a sweaty firefighter on LinkedIn every 3 weeks for eternity.
I feel gross.
A lot of it depends on the size and skill-set of your team and the escalation routes available to you, but in general (and off the top of my head):
- Get the first people on scene to give a summary of the problem as they know it. Make sure everyone actually agrees on what the problem is and what symptoms have been observed. Understand what areas people are currently investigating and make sure they aren't trampling over each other or actually making the situation worse [1]
- Make sure the situation hasn't evolved whilst the first on scene have been investigating the initial symptoms. It's easy to get lost in the weeds digging into a handful of monitoring alerts only to look up and realise there's now 300 and the original problem is only a small part of what's going on.
- If there isn't one already and you're not better doing something else, become incident commander. When done right it's an extremely important and useful role.
- Take over external communication and protect the team from distractions
- Start assessing escalation options
- Take copious notes and keep a timeline
- Act as a shared memory and keep people honest
- Have a less panicked, wider (non minutia) view of the problem
- Start collating and pulling up documentation/schematics so the people at the coalface can quickly query it rather than getting distracted searching for it.
- Be ready to jump, for when someone inevitably asks "can someone check..." or "does anyone know"
- Keep track of the "shared truth" of the incident as it evolves. What have we witnessed, what do we believe is the cause, _why_ do we believe that? Have we invalidated anything, do we need to reassess, are we sure logical lynchpins aren't confirmation bias or dyslexia?
- Onboard new people and hand over if appropriate.
If you get a moment, it can also be a good time to assess how useful your monitoring is during an actual event.
[1] "Hey, server x has flagged on monitoring and my ssh session is hung waiting for a login prompt!" I've been round the houses enough to know this is probably OOM and if I just wait, I'm likely to finally get in. I also know that saying this in a room of 20 technical people, means the server is now processing 22 new ssh sessions and now no one is getting anywhere.
[2] The famous Malcolm in the Middle intro where Hal is tasked with changing a lightbulb and ends up repairing the car. Except in my example the bulb is actually fine and there's a power cut we missed. https://www.youtube.com/watch?v=AbSehcT19u0
Seeing the test firings of the pump was pretty amazing, draining one "swimming pool" and filling another in a minute.
Though that's just gravity-fed, of course. Still pretty cool though, I think (:
Baikonur Cosmodrome: 4,800 gal/s (peak)
Space Shuttle Launch Complex 39: 7,317 gal/s (net)
Wallops: 4,000 gal/s (?)
SLS: 18,333 gal/s (peak)
Mack Super Pumper (this article): 146 gal/s (net)
Replacement new Super Pumper 1: 87.5 gal/s (net)https://en.wikipedia.org/wiki/Napier_Sabre (1938).
Powered the absolute monster that was the Tempest (up to the Mk 2 - they did have reliability issues they never quite solved but 3000+HP out of an engine that weighs barely more than a tonne dry will do that)
https://en.wikipedia.org/wiki/Hawker_Tempest
Was happy to see the name re-used for our upcoming fighter.
We also called the Eurofighter the Typhoon and the (WW2) Typhoon (also a Sabre engine) was the predecessor of the Tempest - it started as a re-wing of the Typhoon but enough changes where made to give it a new name.
Just a devastating superprop in its day.
The engine had a unique characteristic whine or whistle. As an avid train spotter at Waverley station in edinburgh I loved hearing it, saw every one and was in the cab of two thanks to long suffering kind engine drivers.
There was a mini deltic too. I'm not sure it went beyond a testbed loco.
I used to hear it all the time, working in a nearby industrial site. I'd maybe just take five minutes to sit outside and drink my coffee, listening to that weird shimmering howl.
There are no good recordings of it on Youtube and I suspect like a lot of things you have to experience it for yourself.
We probably met. I was there every day traveling to and from school but did casual trainspotting on the side. Oblivious someone would one day write a book with that title..
[0]https://en.wikipedia.org/wiki/Brake-specific_fuel_consumptio... [1]https://en.wikipedia.org/wiki/Napier_Nomad
- Power-to-weight ratios. Critical in aerospace applications.
- Long duty cycles. Everything spins, reducing wear-and-tear relative to reciprocating designs. Maintenance on piston engined aircraft during WWII was a major logistical concern.
- Raw speed. Supersonic flight requires high rotary speeds, and the few propeller-driven aircraft which achieved this had ... issues. Ground crews and pilots suffered health effects from the noise alone, and notoriously often flat refused to work with the XF-84H "Thunderscreech": <https://en.wikipedia.org/wiki/Republic_XF-84H_Thunderscreech...>. At near-supersonic speeds and above, propeller blade tips themselves break the sound barrier, losing aerodynamic flow over the blades, making quite a racket, and greatly reducing efficiency.
Propeller-driven planes remain more efficient than jets in many instances, though last I checked US military forces rely on turboprops over reciprocating engines in virtually all instances, possibly excepting some civilian-based (e.g., Cessna / Piper, etc.) trainer or observer variants.
The youtube channel "Greg's Airplanes and Automobiles" has a nice video about turbo compound engines.
The basics are a single piston, dual (often opposed at an angle or flat-head design as on older BMW motorcycles), in-line (usually 4-cylinder), or V (as in V-6, V-8, V-12, etc.)
Then there are radial engines used in piston-driven aircraft. These virtually always have an odd cylinder count, to prevent locking (there's always an unbalanced force in the direction of intended rotation, or so one hopes).
<https://en.wikipedia.org/wiki/Radial_engine>
There are various rotary engines, with the Wankel design best known. Very high power-to-weight ratios as a result of having three combustion chambers per rotor, but a relative short lifecycle due to wear, and some compromises in efficiency. "Flying car" company Moller International, out of Davis, CA (and apparently inactive since 2015) had at its core a Wankel-based powerplant, with four pairs of counter-rotating engines powering four ducted fans. It sounds like all the angry hornets in operation.
<https://en.wikipedia.org/wiki/Moller_M400_Skycar>
Wikipedia lists some other unusual designs as well: <https://en.wikipedia.org/wiki/Reciprocating_engine#Miscellan...>.
I believe that the axial engine may have been featured in that video mentioned in 'graph 1:
Any tech that includes the word “scavenged” must be cool and efficient
Generally speaking at least, two stroke diesel engines weren't super efficient, but did offer great power output relative to their size.
Also wondering: what replaced this!
(Ed: great reply from Mindcrime. Also, the new Ferrara Super Pumper shows a very impressive ribbed(?) 8-inch "hard suction" hose! There's a whole wikipedia section for these drafting/vacuum hoses: https://en.wikipedia.org/wiki/Suction_hose)
A collection of smaller pumps and monitors, which is likely a better scheme, in terms of flexibility and fault tolerance. While a remarkable design, the single pump with long hoses to multiple hydrants, then radiating to multiple monitors, is a system that takes great coordination and precious time to deploy and rework in action.
The Napier Deltic engine is the party piece in all this. It is an ambitious and yet successful design, intended to push the limit of power-to-weight in a diesel engine. I investigated the state of current diesel locomotive engines in comparison to the Deltic and it remains, to this day, the highest power-to-weight diesel engine in use for locomotives. (There are half a dozen still running in the UK today in limited service.) I've personally visited the Bay City museum to see this engine.
These engines require forced induction; they cannot run naturally aspirated. In its various naval, rail and other applications there were many different induction designs applied to the Deltic: turbos, superchargers and combinations of both. Today, we have electric forced induction, enabled by the high performance electric motors that have emerged elsewhere in transport applications. One thinks of what diesel wonders might be created by combining the Deltic design with electric forced induction.
When pumping a fire engine supplied by a hydrant (or any other pressurized source, as opposed to drafting from a static water source like a pond or lake) there's an idea of "residual pressure" which is monitored by a gauge on the pump panel. The engineer is responsible for making sure the residual pressure doesn't drop below the level where damage would occur to the water system, supply hose, or the pump itself. It's been a few years, but I think most departments spec somewhere around 20psi as the minimum residual pressure they allow.
Also wondering: what replaced this!
The Super Pumper[1], of course! :-)
The new one isn't quite as extreme, not tractor drawn and no separate engine. This is more of a traditional fire engine style platform, but the specs are still pretty impressive.
[1]: https://www.firefighternation.com/lifestyle/new-fdny-super-p...
(Which is why almost ANY fire is a total structure loss unless you can contain it nearly instantly, because the water used to fight it destroys nearly everything. Only if the building is large, concrete, or the damage limited is it worth repairing; most fire-damaged houses get pulled down as it's cheaper overall.)
Mack was awarded the contract to build the truck in 1964 and by the end of the year, the unit was nearly ready to hit the streets of NYC.
Seems amazingly fast by current standards. Those were the days!
See:
https://www.firefighternation.com/lifestyle/new-fdny-super-p...
Your basic modern fire pump unit can pump 2,200 gallons per minute (if you can find a water source that'll give you that much) and it'd typically have a crew of 4-5 firefighters on board.
So you'd probably replace it with 4 regular fire trucks? Then you've got just as much pump capacity, plus you've got the flexibility to send the trucks to different places.
Note that, for what it's worth, fire pumps are generally rated for their capacity when drafting from a static water supply (think, pond, lake, river, etc). Basically all modern fire pumps can easily exceed their rated capacity by a pretty good margin when pumping from a pressurized source, but then you're back to your point of "do you have a source that can supply that?" Still, there are ways. In my firefighting days we had some hydrants in our district (the ones on the big 30" main that ran right down the middle of the county in particular) that could individually supply 2000gpm. And nothing says you are restricted to using one hydrant! There are also all sorts of complex water supply evolutions one can run, involving relay pumping with multiple engines, drafting and using hydrants, etc.
You would initially think that the ignition events would be evenly spaced, but that's not the case. For every delta triplet, the ignitions come rapidly one after another, close together in the cycle.
In that second animation on the page, showing the firing order among 6 delta piston assemblies, if you keep your eyes fixated on any of the six columns, you can see the three firing events. Always C, B, A order.
When the UK converted from steam to diesel it was easier to switch the locomotives while leaving the coach stock as-is. Modern trains aren't like this: they're "multiple units" with more than one drive car. Anyway, a steam engine can generate much more power than a 1950s diesel engine can, particularly factoring in the UK loading gauge which restricts engine height. So in order to make a diesel locomotive capable of taking over from A4 Pacific steam engines on the east coast main line, it was necessary to design a locomotive that had two desiel engines, with a high power to weight ratio. Hence the class 55 cited in the article. The deltic engines were very complex and costly to maintain but solved a problem arising from the transition away from steam. In the 1970s they were in turn replaced by trains with a DMU configuration (HST), featuring a permanently coupled power/van car at each end, removing the need for a single very high power locomotive.
I must also recommend the recently-deceased legend Sebastiao Salgado's photos from Kuwait oil fires.
Of course, you probably want to put out a leak a bit faster than after 55 years.
"7000 ft" sounds wrong to me. That's over a mile of hose. Feels like that's unnecessarily long. I'd love to learn more about this. Anyone know when or what fire this was?
I wonder if maybe it can't even use hydrants that are too near each other in the plumbing graph.
There's a lot of variables in that equation. For example, say you have a "dead end" main that ends somewhere near the fire. If you connect to the last hydrant on the main and start flowing water, there's a good chance you won't get a lot of additional water by connecting to the next hydrant up the street. But if you connect to a hydrant that's on a main that is part of a loop, there's a better chance you'll be able to get more water by doing that.
And without getting into too much detail that would be boring to non-firefighters (probably)... there's actually two big variables for a given hydrant: the maximum volume of water it can supply (in GPM) and the pressure available at the hydrant. And those two things are related. Anyway, net-net, you can have a hydrant that is capable of - in principle - flowing, let's say 2000 GPM. But the pressure at the hydrant is only, say, 40 psi. That means you only have 20 psi (approximately) available[1] to overcome the friction loss in the supply hose between the hydrant and the engine. And that friction loss in turn is a function of the hose size and the flow rate.
Anyway, that results in a situation where you might have a hydrant that could supply you 2000GPM, but if your fire is, say, 1500 feet away, you might effectively only be able to take advantage of maybe 500GPM of that.
And that in turn leads into stuff like using a "four way" or "hydrant assist" valve, or having a relay engine sitting right on the hydrant (to minimize friction loss between the hydrant and the engine) and then using its pump to boost the pressure going to the attack engine. By using multiple engines like that, you can get closer to achieving that hypothetical 2000GPM (or whatever) flow.
It gets pretty complicated, but fortunately fires in urban areas where the municipal water system is the limiting factor seem to be relatively uncommon (but not unheard of!) in this day and age.
[1]: because you don't want to pull the residual pressure down too low or it can damage the water system, supply hose or your pump.
Which still seems like a lot, but not so incredible.
I have never heard of a standard class of pumps for this....other than basically finding a manufacturer who specialized in these sort of pumps.
Read the data sheets and look for those terms, or look for manufacturers of pumps that maximize both.
As a firefighter, the training I've had tells me that they're generally no big deal. You spray water on them to keep the overall temps down, and wait. Not a big deal. The main difference is that they don't tend to go out quickly, so you may be stuck nursing it as it burns itself out for a long time.
As state-of-charge decreases, so does the overall battery pack voltage. Since the motors can only pull some peak number of amps, doing so at lower pack voltage will always deliver less total power.
I own a Model S Plaid and I used to pay close attention to the OBD-II data, out of curiosity.
One day we were out servicing a conveyor drive with a 5hp motor attached to a gear reducer. I pointed out the spec plate on the reducer, it claimed an output of more than a thousand foot-pounds of torque.
"So this thing should be able to beat your Mustang in a race, eh?"
Horsepower is just torque * RPM.
That sounds counterintuitive . What about higher pressure will slow water down?
The price of the system was huge. It's a theme that as we move to better and more efficient systems they become more boring. Most of the magic of driving is lost in electric vehicles, biplanes, and the propellor planes of ww2 capture the imagination in a way jets don't. The monstrously complicated cabins of old 747s are fascinating in a way that modern far more capable planes are not. Back then you had 2 pilots and a guy whose main job was stopping the plane from falling out of the sky! Now it's a bunch of very clever computers under the cockpit that does all of that. It's worth noting that steam engine which was the driving element in the Industrial Revolution and maybe the most important invention in history was originally developed to pump water from mines. Some of these distant ancestors of modern engines are on display in London. James Watt might have predicted a pump like this, but he probably never guessed it would be pulled by anything but a team of horses!
Compare that to Sam Altmans wild prediction that agi will capture "the light cone of all future profits in the entire universe", maybe true, but it will never be as interesting as a steam engine, where the collective ingenuity of a century of engineers and metallugrists is on display in all it's glory.
It sounds counterintuitive because it's not worded well. Imagine a garden hose with no nozzle: The water doesn't go very far, but you can fill a bucket with it pretty quickly. You can also restrict the flow by putting your thumb over the end of the hose. That increases the pressure and allows you to fill up a bucket farther away, but it takes longer because you've lowered the volume (GPM) of water flowing from the hose.
Firefighters use nozzle tips of different sizes to make trade offs between pressure and volume.
I suppose that means back-pressure. More back-pressure on a pump means it can't provide such a high flow rate at the same power output because power = flow rate * pressure.
I remember a cold-war army manual on how to operate captured Soviet equipment; much of it was "long description on what all these dials and parts are for the howitzer - to use, ignore all that shit and fire it, see what you hit, and adjust and try again."