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Thread: Towing the Statue of Liberty

  1. #1
    Vulture of The Western World Eric's Avatar
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    Towing the Statue of Liberty

    How does he get away with it?
    The simple answer is . . . the press lets him. Over and over and over again. Ludicrous claims that ought to trigger the raising of hands - if not questions about his sanity - are stenographed onto laptops and formatted into copy and clicked and sent all over the Internet as imminent, given, factual.
    There will be space tourism to Mars by 2022; fleets of electrified long-haul big-rigs that don’t have to stop every 20 miles or so for recharge pit stops. A new supercar that doesn’t exist - but send me a huge check.
    Remember Yul Brynner in The Ten Commandments?
    So let it be written, so let it be done. Except pharaoh kept his promises.
    Elon promises an electric pick-up truck that will tow 300,000 pounds.
    For the record, this is roughly the weight of the statue of liberty.
    And considerably more than the maximum tow-rating of the Ford F150 (13,200 lbs.) which has the highest tow-rating of any half-ton truck on the market and is the truck Elon says his truck will be "better than."
    It would take probably every F-150 Ford made last year to pull 300,000 lbs. - but Elon Musk has promised his pending electric half-ton truck will pull that load all by itself.
    And no one laughed.
    Even if you took a zero off his claim about the electric truck’s pulling power, the claim would still be ludicrous - and regardless of the mighty torque produced by electric motors, which isn’t a ludicrous claim. It is why EVs like the Model S are very quick - even if they can’t travel very far and take very long to travel again.
    Because towing power is also a function of the capability of the vehicle’s frame and attachment points to handle the strain - something Elon would know if Elon knew anything about trucks. The same goes for the stenographers who “cover” what Elon has to say about trucks.
    Even if the electric pick-up he says he’s developing (no one’s actually seen it and anyone who takes Musk at his word about anything is deserving of everything Elon gives him, or rather takes from him) has a mighty electric motor that develops let us say 1,500 ft.-lbs. of torque, which would about three times the torque of the strongest IC engine available in a current half-ton pickup, unless the truck’s frame can handle the torsional and other stresses, the power of the drivetrain - electric or IC - becomes functionally meaningless after a certain point.
    People who know something about trucks know this. They know that even the heaviest duty non-commercial trucks you can buy - “super duty” 2500s and 3500s - max out around 35,000 lbs. of towing capacity despite having engines that produce almost 1,000 ft.-lbs. of torque - because the steel can only handle so much.
    You can get more pulling capacity, of course - by using more and heavier steel and going much bigger - but now you're talking commercial/big rig stuff.
    There are also brakes and other factors to consider - which Elon apparently hasn’t.
    It’s too bad someone in the assembled gang of stenographers didn’t bother to ask him why he hasn’t. And if he hasn't why he is talking out of his other orifice - again.
    It gets worse.
    Elon claims his fancied - just the right word - electric pick-up will be a better truck than the best-selling F-150 and other IC 1500s in spite of what he has in the works not being a truck at all.
    Trucks - properly speaking - have four wheel drive or at least can be ordered with it. Elon’s “truck” will have all-wheel-drive.
    The distinction is important - to people who buy trucks.
    Four wheel drive involves a heavy-duty gear-reduction system to tackle severe terrain and push through deep snow. AWD just means all four wheels are powered. There is a reason why trucks and SUVs have - and tout - 4WD - while cars and light-duty “crossovers” that look like SUVs have AWD (some of them try to pirate the aura of 4WD by badging themselves as such, but truck people know the difference).
    One’s mind inevitably wanders - or ought to - about the effect of immersion in deep standing water on electric motors and batteries. Trucks get bounced around a lot; dents and bends are mostly cosmetic threats when a truck is a mechanical thing. But what about a dented battery pack?
    A water-logged electric motor?
    Anyone?
    The thing will have the juice to plug in 240V power tools - but of course, that will drain the batteries, which will reduce the range and mean the truck has to be be plugged in sooner. Entropy hands out no free lunches.
    Speaking of which.
    Elon claims - hold onto your wallet - that the electric pick-up will start around $50,000. "Around " being operative - and even if accurate, it's only about $20k more than the base price of the current F-150 ($28,155).
    No worries - as no one Elon knows worries about money, since they have open access to other people's.
    Elon says his electric pick up will “look pretty sci fi,” which is the one non-ludicrous claim he makes. But he should have looked up what “sci fi” refers to, or stands for, before he used that choice term.
    Science Fiction.
    We are dealing with a fantasist here - which would be okay if he didn’t have enablers in the press and his hands in our pockets.
    Nothing wrong with Big Dreams, however ludicrous.
    But a lot wrong with making them come not-true at other people’s expense.
    And with pretending they aren't ludicrous.
    ...
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  2. #2
    Administrator Ken's Avatar
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    Let's see - 300000 lbs is roughly 134 tons. Aussie road trains pull three trailers.
    133 tons divided by three is around 44 tons. That is the current weight of our
    big HGVs IIRC. Big rig HGVs probably average around 500 bhp. Multiply that
    by three gives 1500 bhp - not outside the realms of possibility for grouped
    electric motors. The big factor is not weight, it is rolling friction, obviously
    overcome by road trains. So, without looking too deeply at the hypothesis
    I believe some of Musk's idea is possible - but with a pick-up sized vehicle?
    Maybe not, not even with Duracell batteries.

    Ken.
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    Ken.
    Wolds Bikers, Lincolnshire, England.

  3. #3
    Senior Member grouch's Avatar
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    The limit for hauling is not truck capacity. Current maximum GVW for commercial loads without a permit is 80,000 pounds. A late model tractor can easily pull 150,000 pounds and oversize loads often come close to that. The problem is the road system. The old hard rubber tired trucks of 100 years ago, would haul as much as the operator could pile on it. They would often break through the road surface. Heavier loads require more axles. Look at a really heavy duty dump truck. They often will have two live axles and one or two bogies for heavier loads. Running empty, the bogies are up to the frame and loaded, one or two will be on the ground.

    When I drove a truck back in the early 70's, maximum GVW varied by the state. Anywhere from 72,000 to 72,280 were the limits. Elon Musks ideas may work, but won't be feasible. Drivers are VERY conservative when it comes to their rigs. It is literally, their bread and butter. Lighter materials mean better fuel economy. Lower fuel cost per horsepower is key to profit. However, what use is high power output if you can't get your load to the destination. Diesel fuel quality fluctuates but it's readily available. I can't see the power required to haul a 48,000 pound load coming from electric that is quickly rechargeable. An elctric motor will also require a stiff mounting platform. Modern semi tractors actually have a flexible frame. Watch a heavily loaded tractor trailer start from a light. You'll the the entire cab and dog house raise up on the drivers side. That is the torque of the engine twisting the frame. Make it stiff and you'll see trucks breaking under load. That means the load WON'T be delivered and the driver will be out money to repair. Money that shrinks an already slim profit margin.
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  4. #4
    Administrator Ken's Avatar
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    Another thought. Take a 44 ton capacity trailer - use (say) 5 ton of that capacity
    for a battery pack mounted on the trailer, leaving a 39 ton load capacity.
    Let each trailer have (say) four driven wheels, each with their own motor. Now
    link that to a tractor unit where all the control electronics are fitted. You now have
    a standard size tractor/trailer unit but with a 5 ton battery pack available. To
    upscale to a road train. multiply by three. You now have 15 tons of battery pack.
    I've no idea what a car/SUV battery pack weighs - anyone any idea of what range
    a 15 ton pack might give with, say, a 90 ton load? (We must have at least one
    genius in our midst.) And if you are eavesdropping, Elon Musk, I said it here first.

    Ken.

    p.s. Some Tesla S details. 90kWh battery weighs in at 1200 lbs to give a driving range
    of 265 miles. Car weighs slightly above or below 6000 lbs dependent upon configuration.
    Last edited by Ken; 06-09-2019 at 11:23 AM.
    Die dulci fruimini!
    Ken.
    Wolds Bikers, Lincolnshire, England.

  5. #5
    Senior Member grouch's Avatar
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    Quote Originally Posted by Ken View Post
    Another thought. Take a 44 ton capacity trailer - use (say) 5 ton of that capacity
    for a battery pack mounted on the trailer, leaving a 39 ton load capacity.
    Let each trailer have (say) four driven wheels, each with their own motor. Now
    link that to a tractor unit where all the control electronics are fitted. You now have
    a standard size tractor/trailer unit but with a 5 ton battery pack available. To
    upscale to a road train. multiply by three. You now have 15 tons of battery pack.
    I've no idea what a car/SUV battery pack weighs - anyone any idea of what range
    a 15 ton pack might give with, say, a 90 ton load? (We must have at least one
    genius in our midst.) And if you are eavesdropping, Elon Musk, I said it here first.

    Ken.

    p.s. Some Tesla S details. 90kWh battery weighs in at 1200 lbs to give a driving range
    of 265 miles. Car weighs slightly above or below 6000 lbs dependent upon configuration.

    A 90 ton load will be the entire rig. That's 180,000 pounds. To run heavier than 80,000 pounds requires an oversize permit. Now, those aren't just to get more money out of the driver. There is a LOT of prep involved in an oversize permit. If it's just a load that hangs slightly over the sides and only goes down the interstate,, that's easy. Usually a State Trooper of Motor Carrier Enforcement office will drive the section in that state and make sure there is no restricted load sections. 90 tons though, that is 2 1/4 the maximum weight. Every inch of road will need to be inspected, the bridges especially will have to be checked to make sure they can handle the weight, escort vehicles will need to be utilized for safety, towns will have to have the capacity for that heavy a load to round corners, pavement with pipes close to the surface will have to be bypassed and so on.

    Maybe the unit can be used in Australia where road trains are common. Albeit in the rural parts of the country. In the U.S. with an aging infrastructure, there's no way it could be made legal and no trucker would want to buy it.
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  6. #6
    Administrator Ken's Avatar
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    I wasn't actually looking at the legal logistics of such a load, Grouch.
    I was just musing, broadly on the technical feasibility of building the
    sort of electric vehicle that Musk was proposing. Just looking at the
    limited information I have my guess is that the sort of design I wrote
    about - battery packs on the trailers with the control electronics on
    the tractor - would be technically possible.

    If a 1200 lb battery can push a 6000 lb car 265 miles then upscaling
    to a 5 ton battery (power being pro rata) it should be able to push
    some 54000 lbs. As this load would include the battery the 'carrying'
    capacity would be 42800 lbs of cargo (ignoring the weight of the bare
    trailer.

    I don't know, that it why I was asking for a techy
    genius to do some maths.

    Ken.
    Die dulci fruimini!
    Ken.
    Wolds Bikers, Lincolnshire, England.

  7. #7
    Senior Member grouch's Avatar
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    Quote Originally Posted by Ken View Post
    I wasn't actually looking at the legal logistics of such a load, Grouch.
    I was just musing, broadly on the technical feasibility of building the
    sort of electric vehicle that Musk was proposing. Just looking at the
    limited information I have my guess is that the sort of design I wrote
    about - battery packs on the trailers with the control electronics on
    the tractor - would be technically possible.

    If a 1200 lb battery can push a 6000 lb car 265 miles then upscaling
    to a 5 ton battery (power being pro rata) it should be able to push
    some 54000 lbs. As this load would include the battery the 'carrying'
    capacity would be 42800 lbs of cargo (ignoring the weight of the bare
    trailer.

    I don't know, that it why I was asking for a techy
    genius to do some maths.

    Ken.
    I work in logistics and this touches on what I do all day. I guess I got a little into exact details rather than feasibility. With Musk's Tesla Model 3, there is market demand for the car. There won't be for the truck. Especially in California. I dread getting loads to California due to the restrictive bridge laws. We've gone with Intermodal loading to avoid those. I think there will be less demand for the Tesla truck than there was for the old Ferrari FXXK. The car was gorgeous but only 40 were made, I think, and you had to be invited to buy one. It cost over $300,000, was not road legal and didn't meet any race body rules. A lot of money to just say you own one. People who buy the large rigs to collect them, go for the old stuff.

    I suspect Elon is just flapping his gums to divert attention from something else or to get attention period.

    To get back to the range you mentioned, battery packs are made as efficient as possible. Proportionally, the larger pack will be as efficient as the smaller one. So, it will be 8.333 times as powerful. You can have either range or load. Figure the trailers will be linked electrically with the controls and also to share power if needed. Like current Locomotives. Those share pulling duty to spread pull between more wheels. Anyway, a heavier power pack will appear to come to 750 kwh. If the power ramps up properly, a loaded truck will have about the same range loaded as a Tesla of 250 miles or so. Probably less due to the extra friction of the tires and the worse aerodynamics of a truck. Truck manufacturers have really worked on aerodynamics and made trucks more efficient, but they still behave like a brick.

    This means the Tesla truck will fall short. Assume optimal utility, you'll need to charge every 200-250 miles. A diesel semi will usually run 400-500 miles on long hauls. A little more out west where traffic doesn't hold the driver up. After 10 hours, the driver has a mandatory rest break. Charging the truck will take time from that. Depending on the number and size of fuel tanks, a semi can run 1000 miles between fuel stops if dead heading or lightly loaded.

    Goodness, this makes it sound like I hate electric. If Elon would make a truck with a hybrid design, he might make something that will work and people would buy. Add a small diesel engine to charge the batteries, you could run it in town on electric only and when you hit the open road, use the engine to drive and charge the battery pack(s) too. I think for the larger loads though, the current equipment is the best so far and in the near future. The less a truck can carry, the more the transport cost will be.
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