Ah, the Mack Super pumper. Shame Mack started to struggle in the 60s until the 80s and got out of the fire truck business. They had some very interesting designs in terms of cab design and components. I always loved the F model cab-over which were produced until the early 80s which is what the CF fire truck was built on.
There are numerous "atypical" piston engine layouts, though I cannot recall precisely where I'd seen a reference, probably on YouTube ~10 years ago.
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).
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.
It amazes me what we manage to figure out on the mechanical side of things. Just look at motorcycle engines. Screaming along at upwards of 20k RPM and just taking it in stride and moving people down the road at what might as well be supersonic speed.
I have a question for folks who handle pumps regularly. Almost all pumps are made for water, or sewage. How do you identify if a pump is rated to handle liquid metal or hot fluids (heated chemicals, or contents under extreme pressure)
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.
My dad worked on the Space Shuttle main engine program in the 80s. One of the things they built was the turbopump [0], which generated 23,000HP (and could drain your average home swimming pool in one minute).
Seeing the test firings of the pump was pretty amazing, draining one "swimming pool" and filling another in a minute.
There was a fire station we used to walk past when my little boy was about 2 years old. Often the fire trucks were out the front being cleaned. The fire fighters always let him sit in the cabin. Heaven for 2 year olds obsessed with trucks.
The Plaid can only output its maximum power at 100% state-of-charge (or close to it).
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.
This thing feels like a mortal danger to the (up to 8x!) iron pipes / hydrants it's pulling from, that it'd want to just chew up the very pipes themselves! Or to the building it's hurling 37 tons of water a minute at! I don't understand how a connector hose wouldn't collapse, how it maintains any cross-section rather than being sucked into collapse.
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)
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.
And while we're talking about highly specialized firefighting apparatus... while I don't think Chicago FD ever ran anything quite like the FDNY Mack Super Pumper, they are well known for their use of a piece of apparatus known as a "turret wagon". Basically, it's a big-ass truck with a huge deluge gun (aka "monitor" or "turret") mounted on the back, and with a big intake manifold for receiving multiple supply lines. You could think of a "turret wagon" as being conceptually akin to the "Satellite" units that were part of the FDNY Super Pumper System.
Anyway, one of the best known Chicago Turret Wagons was "Big John" (aka 6-7-3).
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.
Indirectly related, for anyone interested in the topic, Pirault and Flint's Opposed Piston Engines[1] is a nice survey. Unfortunately it seems to be commanding a shocking price these days though.
> During a fire in the Bronx, firemen laid 7,000ft of hose to get to a suitable water supply and the truck pumped as though it was dipping its feet into the ocean.
"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?
SysAdmin related: I was once talking to a fire chief and I asked about how much water the fire engines carried. He said that they carry about enough to put out the typical house fire. The first engine on scene immediately jumps to fighting the fire. The second engine on scene hooks the first engine up to the water supply before going on to fight the fire.
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.
>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.
Great! Now I'll have to see this quote over an image of a sweaty firefighter on LinkedIn every 3 weeks for eternity.
> 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.
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.
Being at the coalface when it's on fire is a very different view of the world to watching other people panic and singe their fingers. It's also very easy to get lost in a chain of technical problems [2] when it's mostly irrelevant to the wider picture.
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
>and flow over 10,000
gallons per minute at low pressures if
the situation called for it. When the
pressure was ramped up to to 350psi,
it could move 8,800 GPM.
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.
The Napier Deltic has a very distinctive sound. You can hear it in locomotive form on youtube. If you are into that sort of thing there are some really good videos on the Rolls Royce Crecy engine as well.
For the curious: most locomotive desiel engine designs have marine origins. That's because ships transitioned to desiel power (from steam) before trains did. At least in the UK. The general design constraints are similar and so when folks began looking into making diesel locomotives they generally selected existing marine designs and adapted them. Often de-rating the maximum power to improve reliability.
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.
30 comments
[ 3.8 ms ] story [ 42.4 ms ] thread> https://en.wikipedia.org/wiki/Napier_Deltic
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:
<https://en.wikipedia.org/wiki/Axial_engine>
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.
Seeing the test firings of the pump was pretty amazing, draining one "swimming pool" and filling another in a minute.
[0] https://en.wikipedia.org/wiki/RS-25#Turbopumps
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.
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)
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.
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.
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!
[1] https://www.amazon.com/-/he/Martin-Flint/dp/0768018005
"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'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.
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.
Being at the coalface when it's on fire is a very different view of the world to watching other people panic and singe their fingers. It's also very easy to get lost in a chain of technical problems [2] when it's mostly irrelevant to the wider picture.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
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.
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.