Load factor = Lift / Weight

[Dutystude]

Originally Posted by custardpsc

Originally Posted by Dutystude

Surely in a constant IAS climb Thrust is greater than Drag.

No, Thrust will equal drag. Newtons first law. If at rest or constant speed, sum of forces must be balanced. If one exceeded the other there would be acceleration.

I am no aerodynamicist but I do have a passing acquaintance with Newton’s laws (as modified by Einstein), Vector Diagrams, the composition of the atmosphere and, what we used to call the Principles of Flight.

PDR

I may have misread your post if you were saying the the Vertcal Components of Thrust and Drag are equal rather than Thrust and Drag are equal.

Of course the relationship between IAS and TAS is a function of air density. But Density is not a Force and plays no part in Newton’s Laws. If we are going to use vector mechanics we need to stick to the Rule of Law.

Custard

You have the First Law right. But in a 70 kt IAS climb the aicraft is not in a steady state but is, indeed, accelerating.

IAS is a red herring. Our ‘frame of reference’ for Newton is the Earth and the appropriate velocity is TAS not IAS.

To an observer on the ground, as you climb at 70 kt IAS you will be seen to accelerate. TAS will increase.

As you maintain a, commendably steady 70 kt IAS climb, to an observer in the aircraft looking out of the window, you will be seen to accelerate in relation to the ground. TAS will increase.

This is is real life. And, according to Newton’s Second Law the forces on the aircraft must be unbalanced.

In our vector diagram for the climb Thrust must be greater than Drag.

Or, if you like, Drag must be less than Thrust