For those times when you find that you are running out of runway length!...
...by then, its too late!... ...!
Calculating Density Altitude:
http://www.flyingmag.com/technique/tip- ... news102711
Paul.... ...!
P.S I find this procedure vital to understand, when taking off, and flying my normally-aspirated (carburettor-engined) aircraft, (Cessna 150/152, Piper Cub, Microlights, Flexwings, etc), at high altitudes!
Its where careful setting of the Mixture Control becomes essential!