Originally Posted by neorich2002
Good afternoon, I wonder if you could help me please, im trying to find some typical numbers for the following.
1.) By how much (i.e. 30% more etc) does the lift on takeoff generally exceed the weight of the aircraft. Also, when defining the maximum take off weight for an aircraft what is the regulation about providing more thrust than weight (i.e. the mtow is the weight at which the lift generated is a minimum of x% more than mtow, or something to that effect)...
This is a simple Newton's Third Law problem in the vertical axis. If the plane accelerates from zero ROC (on the runway) to 30 fps ROC (= 1800 fpm) in, say, 10 seconds, the vertical acceleration averages 3 ft/sec/sec.
Then F(lift for vertical acceleration) = M * a. Since the lift required to carry the ship straight & level is M * 32.2 ft/sec/sec, the added lift for acceleration is about 10% of the baseline S&L value.
So the answer is - it all depends on how fast you achieve the rate of climb.
