Question on forces acting on an aircraft in climb

[PETTIFOGGER]

Capt PB

how does that sound

Er. Interesting but not very convincing, since the atmosphere of Mars is 1 % of that of earth and is mostly carbon dioxide.
Wizofoz

Basically I'm saying this:-
You define weight as being due to gravity and "Apparent" weight as being due to acceleration.
But gravity IS an acceleration. ALL the force being felt by the aircraft is due to acceleration, and there is no need to divide the too into different "Types" of force.

Not quite. Gravity or the gravitational constant (with a big G) is a weak force which exerts an attraction on all objects near and far. Gravity (little g) is the acceleration imparted to objects on or near the surface. Gravitational acceleration is the force or acceleration on an object caused by Gravity.

Classical Acceleration is the change in velocity over time, and is caused by the result of the total of the forces acting on a body of constant mass.[Newton a=F/m]. But there are several types of acceleration – proper acceleration, coordinate acceleration, uniform acceleration, Euler acceleration etc. And just to make life more interesting, we are in a rotating reference frame and subject to 2 or 3 pseudo or fictitious forces.

Wizofoz

Newtons laws can be used to calculate the effects of forces very accuratley, and in Newtonian physics, there can be no acceleration without force. What Newton does NOT do is explain WHY gravity does what it does. GR does, and it does indeed tret gravity AS an acceleration, rather than just a CAUSE of acceleration.

The relevant bit in GR is the Einstein Field Equations where the use of Euclidian geometry is eschewed in favour of Gaussian coordinates to allow accurate curvature calculations. It has been my understanding, possibly imperfect, that it is the need to preserve the equivalence principal that gives rise to discussion of acceleration. Other than that, Einstein treats gravity as a force, as can be seen from the following quotes:
“We must note carefully that the possibility of this mode of interpretation rests on the fundamental property of the gravitational field of giving all bodies the same acceleration, or, what comes to the same thing, on the law of the equality of inertial and gravitational mass.”
And
“Bodies which are moving under the sole influence of a gravitational field receive an acceleration, which does not in the least depend either on the material...”
(source: A Einstein , 1920, Relativity: the Special and General Theory, Chapter 19)

Fortunately, one does not need to be au fait with all of this to fly. The OP’s question can be satisfactorily answered by referring to page 3-19 of the FAA’s ‘Pilot’s Encyclopaedia of Aeronautical Knowledge’ has a section on ‘Forces in Climbs’.
Pilot's Encyclopedia of Aeronautical ... - Google Books