For safety reasons, the cryo liquid natural gas carriers are not allowed into most ports. They discharge to pipelines far out of port. It does make sense to gasify the lng and use for propulsion. Lng requires a heat source to raise temperature at a fast rate for fuel use.
An issue with simple compressed natural gas CNG (as used on autos and city busses) must be pumped to at least 5000 psi for any range. 8000 is more realistic.
Now some school board voted to use cng on the school busses and eventually figured out the difference between propane and cng so all were removed. 50psi vapor vs 5000psi. But propane is dangerous too. Its SG is greater than air so if a tank leaks/burst it remains on ground unless ignited. CNG will dissipate.
Buenos Aires taxis are allowed to only pump, if remember correctly 2-3000psi on CNG. I remember drivers always bitching about it.
Its basically a bomb with huge stored energy mechanical and chemical.
The most efficient simple cycle engine that is safe for common use is diesel.
Boosted diesel-electrics can be very efficient.
My favorite diesel engine of all time was the two stroke twin turbocharged Detroit Diesel Series 60. It used a reverse supercharger to evacuate the exhaust. Light and powerful (all day long) in v8 or v6. New Orleans could have used them with a gearbox disconnect for cheap backups to operate drainage pumps during Katrina.
Boring stuff I guess as diesel is not pc today.
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An issue with simple compressed natural gas CNG (as used on autos and city busses) must be pumped to at least 5000 psi for any range. 8000 is more realistic.
Now some school board voted to use cng on the school busses and eventually figured out the difference between propane and cng so all were removed. 50psi vapor vs 5000psi. But propane is dangerous too. Its SG is greater than air so if a tank leaks/burst it remains on ground unless ignited. CNG will dissipate.
Buenos Aires taxis are allowed to only pump, if remember correctly 2-3000psi on CNG. I remember drivers always bitching about it.
Its basically a bomb with huge stored energy mechanical and chemical.
The most efficient simple cycle engine that is safe for common use is diesel.
Boosted diesel-electrics can be very efficient.
My favorite diesel engine of all time was the two stroke twin turbocharged Detroit Diesel Series 60. It used a reverse supercharger to evacuate the exhaust. Light and powerful (all day long) in v8 or v6. New Orleans could have used them with a gearbox disconnect for cheap backups to operate drainage pumps during Katrina.
Boring stuff I guess as diesel is not pc today.
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A bit more than fifteen years ago, one of my hobbies was flying radio control model aeroplanes. I got into the hobby just as brushless motors and lithium batteries began to replace glow engines - because the electric systems rapidly became more powerful than the nitro-fuelled glow engines!
Not that long ago, Toyota was boasting about achieving 25% peak efficiency in one of their car engines, the highest of any auto manufacturer. Most car engines operate far below that efficiency most of the time.
And that's why even cheap little brushless motors soon beat the pants off small glow engines (which are probably 10% or less efficient). The electric motors were essentially ten times as efficient, which helped compensate for the fact that the batteries were a hundred times worse at storing energy than nitro fuel. Battery weight was kept down by using the smallest battery possible, a strategy that results in only a few minutes of flight before the battery runs out. (This is usually plenty, because small darty models demand intense concentration from the pilot, and five minutes of this is usually all that most people want.)
The other factor helping electric motors in this application is that the power is available at a more appropriate rpm for a model aircraft propeller. (Small props on little glow engines screaming at high rpm are very inefficient, and the beefier torque at lower rpm from small brushless motors allowed the use of bigger and more efficient propellers.)
Nowadays quad-rotor drones are everywhere, and illustrate how surprisingly good electric motors and lithium batteries can be at delivering lots of power - as long as you only need it for a short while.
On the other hand, when you want a model aircraft to fly all the way across the Atlantic ocean, fossil fuels are absolutely the only way to go: The Spirit of Butts' Farm - Wikipedia
-Gnobuddy
Jfetter,
Ahh now I see...I didn't realise that LNGC cant dock at harbour and all the other detail!
Detroit diesels are something I'd just love to see and hear in person - if it wasnt for YouTube I wouldnt know they existed.
Gnobuddy,
Back at university, everyone project seemed to be a quad rotor...yawn...
I tried to build a uC controlled motor test rig (one motoring coupled to one generating)
The simple common RC motor in literally EVERYTHING cheap RS540/560, that is what I used. Those brushed 2 pole PM motors are only 60% efficient, I found in testing.
The lack of a commutator and a simpler mechanical design in BLDC motors should improve a fair bit on that I expect.
Ahh now I see...I didn't realise that LNGC cant dock at harbour and all the other detail!
Detroit diesels are something I'd just love to see and hear in person - if it wasnt for YouTube I wouldnt know they existed.
Gnobuddy,
Back at university, everyone project seemed to be a quad rotor...yawn...
I tried to build a uC controlled motor test rig (one motoring coupled to one generating)
The simple common RC motor in literally EVERYTHING cheap RS540/560, that is what I used. Those brushed 2 pole PM motors are only 60% efficient, I found in testing.
The lack of a commutator and a simpler mechanical design in BLDC motors should improve a fair bit on that I expect.
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In an earlier post I mentioned a friend who had a Chevy pickup in the early 1990s that ran on CNG. It was a factory conversion, with a CNG tank in the fuel bed, one of a run of trucks intended only for fleet service, though at least one ended up in the hands of a private citizen.
Not that long after he bought the truck, that entire run of CNG converted trucks was recalled by General Motors. Two of the trucks had blown up - the 5000 psi CNG tank exploded with devastating violence.
-Gnobuddy
I knew a few people (online) who had built their own motor dynos for these little motors. Quite an interesting project.
I didn't want to take the time to teach myself how to build a dyno, so I just wrote some software that used the basic motor constants to predict the efficiency curve. Close enough for my purposes - 10% accuracy was all I was hoping for.
Knowing the motor characteristics was only a first step - the characteristics of the propeller, and its match to the motor and airframe was even more important, and much harder to get a handle on. You can easily measure propeller static thrust, and calculate propeller pitch speed by measuring its rpm - but you still don't know how the thrust varies with speed throughout the performance envelope of the model. It takes a wind-tunnel to get that data.
For model aircraft, those are incredibly heavy for their power output, and therefore, very 1980s.
They do work well enough for RC cars and whatnot, and very well in RC rock crawlers and other heavy, low-speed models that don't require good power-to-weight ratios.
Was that at peak efficiency? My simulations gave numbers in the 60% - 75% range for peak efficiency. Peak efficiency does go up a bit at higher battery voltages.
One of the tricks used in the RC model world to extract better performance from these cheap motors was to run them at higher than normal voltage, then stuff them in a deeper-ratio gearbox to bring propeller rpm back down where it belonged. The practical limit would be set by things like brush bounce and the rpm at which the rotor windings would start to come apart.
The cheap ones were not a lot better in terms of efficiency (60% - 70%), but they were much lighter for the same output power, had big openings for air-cooling, and the multi-pole, mult-magnet design lowered Kv a great deal; this meant no more need for noisy, expensive, fragile, heavy gearboxes, but direct drive to the prop instead.
The early BLDC motors in the hobby came from individual hobbyists gutting computer CD-ROM drives and rewinding CD-ROM platter motors by hand, but there was soon an explosion of similar motors from China.
For a while the cost of the electronic motor controllers was sky-high, and they were only available from expensive US and European small-scale manufacturers. But once again, Chinese engineers and manufacturers stepped in, and costs plummeted as mass production ramped up.
-Gnobuddy
CNG conversion is quite popular in UK as CNG is half the price of petrol. I had a car converted about 12 years ago as that chugged gas like a tank and it's good bar the slow fill up times.
All the main busses in the town where I live are now on CNG. Big improvement over stinky shaky diesels.
All the main busses in the town where I live are now on CNG. Big improvement over stinky shaky diesels.
When I moved out of Los Angeles, the city transit buses had already all been converted to use CNG.
Behind the scenes, there are some scary stories about working with 5000 psi CNG tanks. One of my neighbours was a mechanic at a local bus depot; one of his co-workers neglected to properly depressurize a CNG tank in the bus he was working on, and when he started to undo the stainless-steel fuel line, it pulled free violently, threw the wrench (spanner) in his hand across the shop, and cut halfway through the steel pillar right next to him. That pillar probably saved his life, otherwise he might have been cut in half.
Apparently 5000 psi CNG tanks make the anti-terrorism authorities very nervous too. No need to build or bring your own bomb; just fire a bullet into a CNG bus fuel tank, and the explosive energy of gas at 5000 psi will wreck half the block.
2174 officially diagnosed Coronavirus cases in the USA now, up from 603 two days ago.
The next major supply chain disruption looks like it will be for anything manufactured in the USA. I stopped at a small local supermarket on the way home from work this evening to buy some fresh salad greens and a pack of tea-bags. The parking lot was full, the aisles were full of shoppers, and the overworked cashier behind the purchase counter said it had been like that all day long. Panic buying, but still civil, unlike the local Costco, where police arrived to break up fights between customers.
-Gnobuddy
Where have you been for most of the last 90 years?
There were several series sold under several names, but all based on the Winton railcar engine taken-over by GM. DD trucks were still on the road 20 years ago; that may even be a DD engine in the old truck parked down the road. DD engines were mainstays of gravel crushers. And of course the larger ones served about half the US railroad locomotives for over 50 years (some individuals ran 30-40 years).
Go down to the docks. Actually to the dock mechanic who will know if there's any DDs in port. DDs were installed in a lot of large boats and small ships. And it is more likely an American ship crossed to your town than a locomotive or gravel-crusher.
They are known for being smoky and leaky. And efficient only by 1930s standards; it must take a lot of blower to keep up with modern poppet Diesels.
Hehe well for the last 40 or so years I've been in the UK
I dont think we saw many of them on our shores, though I have seen the old Comma two strokes (dual pistons/valves?)
As far as rail stock, we have the Deltic(spelling?) and I've knowingly seen, but not heard one of those.
The YouTube vids I have seen though, the revving ability of those Detroit diesels is impressive. I do wonder if they were prone to runaway.
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Yesterday the Locust came through.
Cleaned out groceries etc.
But it's expected, I took cert course it's normal behavior of the media driven public.
CERT is sort of like inactive reserves. Cert is called up when the usual resources are depleted or simply can't handle the volume.
We nowhere close to that.
Community Emergency Response Team | Ready.gov
Cleaned out groceries etc.
But it's expected, I took cert course it's normal behavior of the media driven public.
CERT is sort of like inactive reserves. Cert is called up when the usual resources are depleted or simply can't handle the volume.
We nowhere close to that.
Community Emergency Response Team | Ready.gov
I very much hope it remains that way, in spite of the explosive spread of the virus in the USA.
There were 603 official cases of people confirmed infected with the Coronavirus in the USA on Wed, March 11. Today (March 15) - only four days later - there are 3774.
We're seeing explosive exponential growth in the USA, like we saw in Italy a couple of weeks earlier. And we have no idea how many other Americans are sick and just keeping their mouths shut for fear of being stuck with bills that will destroy them. Thousands more? Ten thousand more?
Italy is currently approaching 25,000 cases. But currently the growth rate is much higher in the USA. My sad prediction: there will be more cases of Coronavirus in the USA than in Italy very soon.
-Gnobuddy
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I imagine everyone on the planet will have a run-in with it.
But bottom line is how many deaths.
The quicker we can burn through it the better. (Imo)
If it had occurred a month or two later, it may have effected the November election.
I think it was under estimated how well China could deal with a major outbreak.
China did it without a vaccine!
But bottom line is how many deaths.
The quicker we can burn through it the better. (Imo)
If it had occurred a month or two later, it may have effected the November election.
I think it was under estimated how well China could deal with a major outbreak.
China did it without a vaccine!
I think the only hobby ship method for parts now is USPS shipping in country or China Post to USPS mailbox. (unless usps suspends too, then what?)
Digikey and Mouser have not sent guidance...
Other methods requiring conventional truck delivery will probably be on hold.
I have not heard anything about DHL,SF,UPS or FEDX.
Strange even in darkest hour China was fulfilling orders and shipping to US.
I suppose one person losing money means another gained it. So is someone short/gaining similar to 911?
Digikey and Mouser have not sent guidance...
Other methods requiring conventional truck delivery will probably be on hold.
I have not heard anything about DHL,SF,UPS or FEDX.
Strange even in darkest hour China was fulfilling orders and shipping to US.
I suppose one person losing money means another gained it. So is someone short/gaining similar to 911?
FedEx has been hauling-box from Florida to NC to PA to Connecticut just like they expect to deliver to me on Thursday.
In other, unexpected, news: the paper business in Maine used to be huge but has been in decline 10 or 20 years.
Maine Factory Begins Making TP Just In Time
"Bangor-based company TissuePlus just began turning raw tissue paper into finished toilet paper.
"It was only last week that the factory, located on the outskirts of Bangor, began making finished toilet paper.
"Just in time, too. Even before it was announced that Maine had its first positive COVID-19 case, panicked shoppers began clearing shelves of shelf-stable food and toilet paper."
Maine Factory Begins Making TP Just In Time
In other, unexpected, news: the paper business in Maine used to be huge but has been in decline 10 or 20 years.
Maine Factory Begins Making TP Just In Time
"Bangor-based company TissuePlus just began turning raw tissue paper into finished toilet paper.
"It was only last week that the factory, located on the outskirts of Bangor, began making finished toilet paper.
"Just in time, too. Even before it was announced that Maine had its first positive COVID-19 case, panicked shoppers began clearing shelves of shelf-stable food and toilet paper."
Maine Factory Begins Making TP Just In Time
Oh, I should add, deliveries in China were working just fine even at the peak of the epidemic. My wife sent a number of care packages to her family in China 1-2 months ago by Canada Post and small business shippers. The only 2 packages that didn't make it were 1 with canned food, and 1 with N95 masks in original packaging. We think the canned food wasn't allowed because the scanner couldn't see the contents, and the N95 masks in original packaging were just too valuable on the street. A number of packages with N95 masks in vacuum bags got through
I don't think it's over in China yet. The virus still exists and the vast majority of Chinese people have not been infected. I would think that once they leave their homes and start going to work again there will be an uptick. I hope I'm wrong but....
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