PPRuNe Forums - View Single Post - Question on forces acting on an aircraft in climb
Old 9th May 2009, 05:17
  #40 (permalink)  
Wizofoz
 
Join Date: Jun 2001
Location: Boldly going where no split infinitive has gone before..
Posts: 4,790
Received 45 Likes on 21 Posts
Airbus,

Good explanation here-

Pilot's Web The Aviators' Journal - Forces Acting on an Airplane

But first, you must get some basic concepts right.

Attitude is not directley related to angle of attack, and thus not directly related to lift, as attitude is angle reference the horizon whilst AofA is reference the relative airflow.

Vertical component of thrust is NOT lift. Lift is force perpendicular to airflow. Thrust is (more or less, depending on the thrust line of the engine) parralel to airflow.Weight always acts directly donwards, so a compponent of lift plus thrust must equal weight for equilibrium. All of this is true of a hovering helicopter.

If lift (or indeed, the sum of all forces acting vertically upwards) was greater than weight, the aircraft wouldn't just climb, it would continuously Accelerate vertically upwards, that is it would be under a constant g force of greater than one, with a constantly increasing climb rate. When you climb your 'bus, are you constantly pushed down in your seat by a force greater than your normal weight? Does it maintain a constant rate of climb?If not, your aircraft is in equilibrium, which couldn't happen if the vertical component of lift was greater than weight.

I think (and it's not uncommon) that you are confusing Lift with Co-efficient of lift, which is only one part of the lift equation.
Wizofoz is online now