[Spaceships] SS Mecha vs. HT/UT Tanks, and 'ships vs. jets

[Langy]

Battlesuits use significantly different armor types in Ultra-Tech than those in Spaceships. They provide something like 2-2.5 times as much DR per pound.

You need to do some serious figgling with armor layout for Spaceships-built tanks to have the same amount of armor as tanks in either HT or Ultra-Tech. You might need to use something like my super-dense ships thing in order to get enough armor available and to make sure a tank is scaled properly - a 68 ton Abrams is SM+5, for example, but in Spaceships that'd be pretty close to SM+6.

Spaceships jet engines are way, way more efficient than realistic jet engines. For example, the F-22 Raptor:

Empty Mass: 20 Tons
Engine Mass: 4 Tons (2 Pratt and Whitney F119's)
Fuel Capacity: 9 Tons Internal
Weapon Capacity: 1.5 Tons Internal, 10 Tons External (ignoring the gun system)
Thrust: 35 Tons
Range: 1840 miles with 2 external fuel tanks (13 tons of fuel, total mass 35 tons)
Supercruise speed: 1,220 MPH

The range gets you 131.5 miles per ton of fuel

This gets a total loaded mass of 20+9+1.5+10=40.5 tons if you include the hardpoints. If you don't include the hardpoints (like the figure for loaded weight on Wikipedia) it's only 30 tons. Those 4 tons of engines only provide 35 tons of thrust, giving you just over 1G of thrust. Spaceships assumes you get 1G per 5% of loaded mass as jet engines.

If you design it as an SM+5, 30 ton spacecraft, you get something like this:

Front
[1] Armor
[2] Control Room (Ejectable)
[3] Medium Battery (the 20mm gatling gun, plus 480 rounds)
[4] Tactical Sensors
[5] Defensive ECM
[6] Defensive ECM

Center
[1] Armor
[2] Medium Battery (internal missile/bomb loadout)
[3] External Hardpoint (capable of holding up to 5 tons)
[4] External Hardpoint (capable of holding up to 5 tons)
[5] Fuel Tank (Jet Fuel)
[6] Fuel Tank (Jet Fuel)
[Core] Fuel Tank (Jet Fuel)

Rear
[1] Armor
[2] Fuel Tank (Jet Fuel)
[3] Fuel Tank (Jet Fuel)
[4] Jet Engine (1/3 G)
[5] Jet Engine (1/3 G)
[6] Jet Engine (1/3 G)
[Core] Fuel Tank (Jet Fuel)


With the 5 tons of extra fuel tanks, the F-22 has a range of 1,840 miles, assumably at a supercruise velocity of 1,220 MPH. That means with 1.5 times as much fuel as it can carry internally, the F-22 can travel for 1.5 hours. Each of the six fuel tanks provides only ten minutes of jet fuel, not a full hour like it's listed in Spaceships.

It's maximum speed is also 1000 MPH slower than listed in Spaceships.