Roger replies to me. > >The problem is that they don't really look like ducted fans. > >How fast has the air to go through those little nozzles? > > Each square metre of nozzle/rotor/etc. exhausting air at jet engine > speed can provide about 10kN of thrust*. A full-up Apache at 10,433kg > (MTOW) would need 10.4m^2 of exhaust area to get off the ground. (Its > actual rotor has an area of 168m^2, so it actually needs to throw air > downwards at only 22m/s.) What's the MTOW of the vehicle? > > * thrust/area = airdensity * speed^2 > modern jet engine exhaust speed = ~200mph > standard air density = 1.225kg/m^3
48 short tons. I'd need 43 square meters, which means two 5 meter fans. For the smaller fans, the exhaust speed would have to go up quite a lot. Eight 1 meter fans would need 500 mph. One wouldn't want to walk under that, even in an armored suit. Regards, Onno _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
