Acft. Range Calculations Wonky?

[43Supporter]

Flipping through one of my old folders, I noticed something about the range calculations for airplanes and helicopters: They are Badly Off.

For example: I have a fighter design, the _Adler_ ("Eagle"). It has a Super Acft. plant, giving it [50 x 16 =] 800 Power Units [PU] total. It has a top speed of 447.5 MPH; assuming "cruise speed" is 60% of top speed (more on this later), it cruises at 267.5 MPH. If one plugs these values into the "PU-per-mile" formula, one gets:

(800 x (267.5 - 75)) / (10,000 x (447.5 / 240)) = 8.26 PU/mi.

which means it has a range at cruise of only 100 miles, and falls out of the air after 30 minutes.

Similarly, the _Kugelblitz_ ("Ball Lightning"), with a Small Acft. plant [500 PU] and TS of 342.5 MPH (205 MPH cruise):

(500 x (205 - 75)) / (10,000 x (342.5 / 240)) = 4.55 PU/mi.

which isn't much more than 100 miles at cruise, and similarly short duration.

Not helping: In Reality, an airplane's "cruise speed" is 80-90% of top speed, not 60%.

Given even the really small LSAs and trainers have ranges and endurances closer to two hours and 300 miles at "cruise" (which, as noted, is much faster than what _CW_ lists), I'm thinking the range calculations are in desperate need of a Rethink. Perhaps something closer to the gasburners' "MPG" figure, with adjustments depending how far above|below cruise on is?