How do you reconfigure a supercharged engine for this role? Piston-powered fighter aircraft of WWII needed heavy supercharging for maximum power, but the more mixture you cram into a cylinder, the closer you push it to detonation—a destructive form of combustion. To prevent this, you reduce the compression ratio. This is why the original H2/H2R had its low 8.5:1 compression ratio. Yet fuel efficiency and compression ratio are linked; the lower the compression, the higher the fuel consumption. This is okay in a fighter, for when you firewall the throttle to close on the enemy, fuel economy is not your big concern.