Viewing 15 posts - 31 through 45 (of 67 total)
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  • #2624
    Brian H
    Participant

    As far as the helium thrust or waste or exhaust: I think they’re all non-issues. Remember that the current generated, which is the whole point and output of the reactor, is derived from the passage of the alpha beam down the core of a magnetic coil, which produces current in the process of decelerating the beam to almost a dead stop. The ionized gas is neutralized from a ground/sink source of electrons, and you’re left with placid, everyday He4. Use for party balloons. Not hazardous. Not energized. Not important.

    #3959
    Aeronaut
    Participant

    Jolly Roger wrote:

    Reactor plus shielding is 2 meters across but whole thing, including capacitor bank may be more like 3x2x2 meters.

    Duke Leto wrote: So barring some miracle discovery in radiation containment, there’s an asymptotal lower limit on unit size of about a cubic meter. Ergo no fusion-electric car or propellor airplane…

    It may be possible to design a semi-tractor or bus around a Focus Fusion reactor, but I wouldn’t be too comfortable being stuck in rush hour traffic next to an active gamma and x-ray source. But then again, I have been involved in shipping low-level fission waste down the road, so there is not much difference.

    Trains and ships will not be a problem fitting an FF reactor aboard. A large plane could carry one under each wing or in its belly to power electric ducted fans.

    1 Watt = 1 Newton-meter/second, therefore 5 MW = 5,000 kN-m/s. The engines of a Boeing 747 develop ~280 kN of thrust. (The units aren’t quite right, so this might be mixing “apples-and-oranges”.)

    Does this mean that if a reactor/engine system had an efficiency higher than ~6% a Focus-Fusion-powered 747 could fly? If not, why not?

    2 tons of FF mass +~2 tons of motor mass (G.E. Pegasus line- up to 22,000 HP @ 15MW and your choice of 13.2 or 6.6kV) is why I agree with Transmute. But it could make one heckuva marine drive when geared down from the 1,440 to 3,960 RPM shaft speed range. Best way to shop motors seems to be by specifying one or both of these voltages.

    Here’s the bad news on required HP to retrofit large turbofans: Getting the power units to line up is presented as a chicken and egg type thing. We need HP to size the electric motor, but turbines are rated in pounds of static thrust. Here’s the formula using a 747-400’s 190 MPH (279 ft/sec) full power takeoff: HP= (velocity * thrust) / 550 / number of engines if using combined thrust. (English units only).

    This works out to: Electric Motor HP= [(279 * 248,000) / 550] / 4 which resolves to 31,451 HP per engine. (!!!!!!!!!!!!)

    Notes- I picked 190 MPH full power takeoff speed because I’d prefer a more cautious flight crew, and at that point we know velocity and thrust with the least amount of guessing. I took the engine specs from the FAA engine certification sheet. http://www.aerospaceweb.org/question/propulsion/q0195.shtml provided the basis for the formula and a worked-out example of a NASA 747-200 cruising to double-check my calculations. While they didn’t provide the formula directly, this article does explain the approach and options better than anything else I found online.

    btw- I began this project expecting the Flying Sub (damn that was a sweet ride- especially re-entering the water!), then thinking the 747’s 232 ton fuel + engine weight would surely be more than enough. Once I started shopping motors I began wondering if I Big Bird was going to be able to carry any paying freight.

    One thing I haven’t checked yet is DC motors.

    #3963
    JimmyT
    Participant

    The point in packaging a unit in a modular shipping unit is not to provide mobile power. It’s to make the power units easy and inexpensive to transport to the site where they are to be utilized.

    #3968
    Aeronaut
    Participant

    JimmyT wrote: The point in packaging a unit in a modular shipping unit is not to provide mobile power. It’s to make the power units easy and inexpensive to transport to the site where they are to be utilized.

    I fully agree with the need for standardized modular form factors, Jimmy. The standard shipping container is the best current candidate due to the weight of the frame required to lift 2 tons of mass (64 tons) by crane. Since it could fit in air freight (if it wasn’t so durn heavy), two units would be at or near even a 747-400F’s 140 ton payload weight limit. What a picture, huh? Now, let’s imagine how we’re going to load the container ship- these go in the bottom of the hold to keep the ship stable. Somewhere between 100 and 1,000 FF pods may be enough mass to require sailing with an “empty” hold and deck.

    Licking the mass challenge is going to be the key to economical shipping and wider application of FF.

    #3971
    Brian H
    Participant

    Aeronaut wrote:

    The point in packaging a unit in a modular shipping unit is not to provide mobile power. It’s to make the power units easy and inexpensive to transport to the site where they are to be utilized.

    I fully agree with the need for standardized modular form factors, Jimmy. The standard shipping container is the best current candidate due to the weight of the frame required to lift 2 tons of mass (64 tons) by crane. Since it could fit in air freight (if it wasn’t so durn heavy), two units would be at or near even a 747-400F’s 140 ton payload weight limit. What a picture, huh? Now, let’s imagine how we’re going to load the container ship- these go in the bottom of the hold to keep the ship stable. Somewhere between 100 and 1,000 FF pods may be enough mass to require sailing with an “empty” hold and deck.

    Licking the mass challenge is going to be the key to economical shipping and wider application of FF.

    ?? Run that by me again? How did 2 x 2 tons get to = 140 tons?

    #3974
    Aeronaut
    Participant

    Brian H wrote:

    The point in packaging a unit in a modular shipping unit is not to provide mobile power. It’s to make the power units easy and inexpensive to transport to the site where they are to be utilized.

    I fully agree with the need for standardized modular form factors, Jimmy. The standard shipping container is the best current candidate due to the weight of the frame required to lift 2 tons of mass (64 tons) by crane. Since it could fit in air freight (if it wasn’t so durn heavy), two units would be at or near even a 747-400F’s 140 ton payload weight limit. What a picture, huh? Now, let’s imagine how we’re going to load the container ship- these go in the bottom of the hold to keep the ship stable. Somewhere between 100 and 1,000 FF pods may be enough mass to require sailing with an “empty” hold and deck.

    Licking the mass challenge is going to be the key to economical shipping and wider application of FF.

    ?? Run that by me again? How did 2 x 2 tons get to = 140 tons?

    Glad you asked, Brian. It’s in the fine print, where the mass is quoted as 2 tons. I’m hoping that it is more like .2 tons. It’s right around 38:00 into the video, right after the materials required section.

    #3975
    Duke Leto
    Participant

    Favor 2 tons, Lead is not a light metal.

    I assume that the airliner tonnage max was more predicated on the density of the payload than the weight, or that he was talking about using the reactors as power supplys for propellor driven airliners and despaired of doing so.

    You’d have to be pretty daft to want to transport a non-active FF reactor by plane though, there’s no benefit to not doing so by rail and sea.

    #3977
    Brian H
    Participant

    Aeronaut wrote:

    The point in packaging a unit in a modular shipping unit is not to provide mobile power. It’s to make the power units easy and inexpensive to transport to the site where they are to be utilized.

    I fully agree with the need for standardized modular form factors, Jimmy. The standard shipping container is the best current candidate due to the weight of the frame required to lift 2 tons of mass (64 tons) by crane. Since it could fit in air freight (if it wasn’t so durn heavy), two units would be at or near even a 747-400F’s 140 ton payload weight limit. What a picture, huh? Now, let’s imagine how we’re going to load the container ship- these go in the bottom of the hold to keep the ship stable. Somewhere between 100 and 1,000 FF pods may be enough mass to require sailing with an “empty” hold and deck.

    Licking the mass challenge is going to be the key to economical shipping and wider application of FF.

    ?? Run that by me again? How did 2 x 2 tons get to = 140 tons?

    Glad you asked, Brian. It’s in the fine print, where the mass is quoted as 2 tons. I’m hoping that it is more like .2 tons. It’s right around 38:00 into the video, right after the materials required section.
    See the italicized clause above. You appear to be stating that 2 2-ton units would exceed the 140 ton payload limit. By my arithmetic, 2×2 = 4, not 140. But then, I’m old school. 😛

    Furthermore, according to this: http://www.boeing.com/commercial/startup/pdf/freighters/747f_payload.pdf the weight limit for about a 3,000 nautical mile range, is over 280,000 KG. That’s KG, not lbs. So that is over 280 tons, not 140. Since 2 units would weigh 4,000 lbs., or about 2,000 KG total, that would mean you could put 140 units in a 747, if only they would fit.

    Volume, not mass or weight, would be the limiting factor.

    Since the volume available is about 23,000 cu’, and one FF unit is about 128 cu’, that means with ideal packing no more than 18 would fit in the 747 400F belly. Which would weigh only 36 tons, under 1/7 the limit. That 747 would feel light as a bird!

    #3978
    Aeronaut
    Participant

    RTFQ: Weight in pounds= 32*mass. The 140 ton limit is for an 8,000 mile range.

    #3979
    Aeronaut
    Participant

    Duke Leto wrote: Favor 2 tons, Lead is not a light metal.

    I assume that the airliner tonnage max was more predicated on the density of the payload than the weight, or that he was talking about using the reactors as power supplys for propellor driven airliners and despaired of doing so.

    You’d have to be pretty daft to want to transport a non-active FF reactor by plane though, there’s no benefit to not doing so by rail and sea.

    Yeah, I guess we’re stuck with that weight. Still, outfits like F.E.M.A. wouldn’t necessarily be daft in the air freight scenario. What my examples above vividly illustrate is 2 modes of shipping that would look almost empty, even when loaded near their weight limits.

    Jolly Roger was talking about keeping just the fan and replacing the jet turbine with a FF and electric motor. FF changes everything. In this case, it changed power to weight ratio into weight to power ratio, lol.

    #3980
    Aeronaut
    Participant

    JimmyT wrote: The point in packaging a unit in a modular shipping unit is not to provide mobile power. It’s to make the power units easy and inexpensive to transport to the site where they are to be utilized.

    I was going thru Rematog’s brown site / green site numbers for a 100 unit, 2GW plant a few hours ago. Why not make a domestic form factor in a steel cage that a crane could literally stack up to make significant portions of the building’s structure? Now no box requires 6 sides enclosed, and foundation design could be simplified. We’ve modularized not just the shipping container, but most of the building, too.

    #3981
    Brian H
    Participant

    Aeronaut wrote: RTFQ: Weight in pounds= 32*mass. The 140 ton limit is for an 8,000 mile range.

    ??? What is your point? An 8,000 mile range will encompass most of the planet from any given start point.

    Why is the weight in pounds 32 * mass? Mass = weight here on Earth anywhere within many miles of sea level.

    Believe me, 747 freighters would go broke fast if they could only carry 4 tons!! A passenger version could only carry <30 passengers if that was a weight limit!!!
    //Addendum.
    Attempting to deconstruct the numbers, 32*mass in Kg. would be the number of ounces. (Actually, you have to add 10% because 1 kg. = 2.2 lbs = ~35 oz.)

    Do we have a wee units confusion here? Ounces matter for gold and platinum, but not so much for general cargo!

    #3982
    Duke Leto
    Participant

    For once, Brian H and I are in clear agreement.

    Neither of us have the slightest idea what Aeronaut is getting at.

    #3983
    Aeronaut
    Participant

    Duke Leto wrote: For once, Brian H and I are in clear agreement.

    Neither of us have the slightest idea what Aeronaut is getting at.

    Sorry, gentlemen. the point I was trying to make is that a machine with a mass of 2 tons has a weight of 64,000 pounds plus shipping container weight. This is not casual shipping. It’s more like chartering the flight or boatload.

    #3984
    Brian H
    Participant

    Aeronaut wrote:

    For once, Brian H and I are in clear agreement.

    Neither of us have the slightest idea what Aeronaut is getting at.

    Sorry, gentlemen. the point I was trying to make is that a machine with a mass of 2 tons has a weight of 64,000 pounds plus shipping container weight. This is not casual shipping. It’s more like chartering the flight or boatload.

    Your point is — ahem — dull and broken. 2 tons mass = 4,000 pounds. Period. Please explain where your extra 60,000 pounds comes from!

    That’s as simple as I can make it. 1 ton = 2,000 pounds. 2 tons = 2,000 + 2,000 = 4,000 pounds. Honest Injun! :coolsmile:

    If you are still rolling in the mass of the water shielding, fuggedaboudit. Not even in the Sahara would anyone pay air freight (or any other kind of freight) to ship a generator with a pre-loaded water shell rather than access local supply.

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