Why don´t these figures match up?

[ATAG_Snapper]

Nifty procedure -- much more precise than mine. Mousing over the airspeed indicator in the RAF fighters may introduce error; the readout rounds off to the closest +/- 10 mph. I don't know if that's the case with LW fighters (although the rounding off to the closest 10 kmh would introduce less error, I expect.)

Trying your procedure over a longer distance would be interesting to see if any error decreases, or, as you suspect, may stay the same % anyway.

If weather and cloud cover is ever introduced, your findings will be instrumental in calculating how to meet the waypoints towards the target......or missing them outright.

Good post. My head hurts. LOL