Hello
I have just arrive to the Inner Sphere and as i was looking to the conventional fighters with Fusion engines at my militia base i realize that they need Fuel... Why?
We have very powerful electric engines and compressors as well as high bypass or even Scramjets. We fly in a compressible fluid and got a electric & heat generator aboard this machines why do they need fuel if not for Postcombustor for the extra push or to climb to the limit and see the space
PS: i suppose it's do the game mechanics but if I'm wrong please tell me (Do LAM needs fuel once in atmo?)
During Aerotech 2-Revised's writing, I proposed that fusion-breathing conventional fighters (at least) should have unlimited ranges, maybe just up to their thrust rating. (Overthrust might entail dumping, say, water into the exhaust.) That got some traction with a paragraph on "airbreathing" fighter variants, but it was never carried to the logical end. BT fighters have always carried "fuel" regardless of whether they're surrounded by plenty of reaction mass in an atmosphere.
Jump jets do breath air for reaction mass, but can only work briefly because something something corrosion oxidation (see Tech Manual.) Again, that was me trying to explain why jump jets can't work continuously and why conventional fighters need hydrogen. It doesn't hold up well to scrutiny.
![Rosy azn](https://bg.battletech.com/forums/Smileys/default/azn.gif)
Also, as an aside, the fuel you buy in ASF isnt hydrogen with the images of fighers we have. It must be something dense instead. Hydrogen just takes up far far too much volume, and since the visuals of aerospace/conventional fusion fighters isnt a zeppelin/balloon shape, the fuel is likely some neutral liquid metal
The fuel is explicitly liquid hydrogen for fusion-powered aerospace fighters and other spacecraft, something noted in StratOps. While artwork is canon, it is the canon of last resort after rules, novels, and sourcebook fluff. StratOps' fluff and rules say the fuel is liquid hydrogen, so it's liquid hydrogen, making the artwork incorrect.
But, then again, BT's artwork also gets aerodynamics of aerospace fighters very wrong. And spacecraft artwork plus avowed spacecraft dimensions mean that DropShips and massively armored WarShips have armor thinner than paper or a thin coat of paint. A big DropShip like a Mammoth could almost float in the air if you took out the cargo and swapped its internal atmosphere for hydrogen gas or helium. Point being: take the artwork with a grain of salt, like BT's fact checkers do.
It's not so much FUEL, as reaction mass. yOu can use the fusion engine to heat up a given liquid, under compression, and ride the steam. Basically the advantage of a fusion powerplant in an airframe, is that if you have a reactive liquid (doesn't have to be jet fuel) it'll work as reaction mass.
By the time you're up to 100-ton fighters about half the hydrogen is being fused to helium, so it is both reaction mass and fuel. Strategic Operations goes into that in some depth.