180mph IAS on 10.000 Feet should be 216 Mph. But indeed, if you are descending or ascending, the TAS will be diffrent. And for Dead reckoning navigation, you should use Ground Speed. So wind direction and speed should be calculated as well.
TAS increases by 2% for every 1000 Feet. This is a rule of thumb wich can be used for speeds below 400km/h 248Mph or 216Kts.
When done properly, Dead reckonging can give immense satisfaction! If only we could get the level autopilot to work in COD....
|