Far larger than the small fusion engines seen in Battletech cars.Ford Prefect wrote:It's really small. They're called 'ultracompact' for a reason.
Oh no, mechanical compensators are heavy. Who would have thought? If you want to compare computers you can get the same effect with a cybernetic implant.One ton targetting computers, anyone?
How dose that square with Stark saying they don't use much energy at all? If they produce so little energy and their reactors run so cool, why would they melt with such a huge surface area? The only thing I can think of to combine little power use with great heat is if beam weapons put out a lot of heat.The actual lattice of Minovsky particles created also serves to insulate the mobile suit from the great heat generated by operation of the reactor, making it easier to radiate heat; if it wasn't for the I-field used to catalyse the reaction, mobile suits would melt.
So far I've learned that Minovsky reactors produce more energy than Deuterium-Helium3 fusion and run pretty cool. I haven't found anything that gives hard numbers to say for sure.Stark wrote:Do you have any actual evidence that BT reactors produce more power for a given reactor system displacement?
I know a typical 100 ton Battletech fighter produces about 4.6 terrawatts.
Here are some numbers on larger craft.Cray wrote:Assume a unit is accelerating at 1G / 2 thrust points. Knowing the 2 thrust points, you know fuel consumption of the unit per second. (For example, a fighter has 80 points per ton. A turn is 60 seconds long. 2 thrust points equals 1/40th of a ton per minute, or 1/2400th of a ton per second: 0.4167kg of fuel per second.)
Next, find the thrust of the unit in kilograms force (this only works assuming 1G). Basically, it's the mass of the vessel in kilograms. For a 100-ton fighter, that's 100,000kg.
Next, divide the thrust in kilograms-force by the fuel consumption. For a 100-ton fighter, that's 100,000kg / 0.416666666666666666666666666 66666 kg/sec = 240,000 seconds.
That number is the "specific impulse," (Isp) a term you'll find in common use in rocketry discussions. For comparison, the shuttle's SRBs have an Isp of about 275 seconds, while the main engines reach about 453 seconds. You can read specific impulse to mean, "The rocket engine consumes 1 pound (or kilogram) of fuel per [Isp] pounds (or kilograms) of thrust."
Exhaust velocity is equal to Isp times G (9.8m/s/s). The shuttle's main engines' exhaust velocity is 453 seconds * 9.8m/s/s = 4493m/s. A 100-ton fighter's exhaust velocity is 240,000 x 9.8 = 2,352,000m/s (not quite 1% of light speed). It's reasonable and plausible for fusion rockets to deliver up to about 1 million seconds of Isp.
Plug exhaust velocity into the jet power equation and you have an inkling of how many watts a fighter or warship is blowing out its tailpipe. A 100-ton fighter's exhaust - at 1G - is delivering:
[2,352,000m/s] * [980,000 newtons] * 0.5 / 1 (for 100% efficiency) = 1.152 terawatts.
A typical 100-ton fighter can crank up to 4Gs, quadrupling power output.
Fallguy wrote: The real problem is the energy required. All Small Craft, Dropships, Jumpships, and Warships break thermodynamics by getting more thrust energy than hydrogen fusion can produce realistically. Hydrogen fusion produces 3.4 x 1018 ergs/gram or 340,000 terajoules/ton. Thus, your typical Military Dropship with a burn rate of 1.84 tons/day/G has an energy potential of 625,600 terajoules per day or 7.24 terajoules per second at 1-G of thrust if you could somehow get 100% efficiency. However, if you run the numbers on even a 500-ton Dropship you get the following:
Ship Mass: 500,000 kg
Thrust @ 1G: 4,903.325 kN
Base Fuel Rate: 0.021296 kg/s
Base ISP: 23,478,261 seconds
Base Exhaust Velocity: 230,243,087 m/s (76.8% of C)
After factoring in Lorentz transformation of mass at velocities approaching C we get the following:
Ship Mass: 500,000 kg
Thrust @ 1G: 4,903.325 kN
Base Fuel Rate: 0.021296 kg/s
Lorentz factor: 1.26093435
Relativistic Fuel Mass: 0.026853 kg/s
Relativistic ISP: 18,619,733 seconds
Relativistic Exhaust Velocity: 182,597,205 m/s (60.9% of C)
Now that we know the true Exhaust Velocity, we have to determine the energy cost. The basic thrust formula is not enough, as relativistic effects have to be considered. In addition to the kinetic energy cost, there is the energy cost of forcing the propellant up to over 60% of C. Thus:
Thrust x EV x 0.5 = 447.6667 gigajoules/second
Relativistic Fuel Mass - Rest Fuel Mass = 0.005556935 kg/s
0.005556935 kg/s x C² = 499,432.4317 gigajoules/second
Total Energy Cost: 499.88 terajoules/second
Efficiency: 6,903.71%
So even a 500-ton Dropship is getting 69 times the potential energy of hydrogen fusion to get the thrust necessary to produce 1-G of thrust. In fact, anything with a 1.84 ton/day/G fuel usage rate with a mass over 56.5 tons is operating at greater than 100% efficiency. A 500-ton Dropship would have to use 200 times the fuel it does (368 tons/day/G) to get to a realistic 40% efficiency. This does not account for mass reduction as fuel is burned, however... but that gets things even further complicated. Cheesy
Cost and ease of use. Also, your fixating on Gundams. I was primarily referring to spacecraft. Getting large amounts of water or hydrogen is far easier than getting large amounts of Helium-3. Since Battletech fusion engines scale down a lot farther than Minovsky fusion engines you can put them in a lot more things. Fusion powered drones, light vehicles, and missiles.Even if it were true, what actual benefits would there be, since Gundams instantly make the entirety of BT mechs obsolete?
That raises a question. UC Gundam warships can fire missiles, but do we know if their fusion powered? If not, the ability to slap a fusion engine in their would be an improvement.