Inertia and HCL

[DGdaPilot]

Ok, in a constant-altitude, constant-airspeed, constant-bank turn, inertia (centrifugal force) is always opposite of horizontal component of life (centripital force). But, is inertia also EQUAL to inertia? If not, then how is load factor (the average vector of weight and inertia) always equal and opposite to total lift? I was trying to explain all of this to my student and I caught myself.....don't positive G's occur when HCL overcomes inertia?
Confused,
DG

 

[Kingairrick]

Ok, in a constant-altitude, constant-airspeed, constant-bank turn, inertia (centrifugal force) is always opposite of horizontal component of life (centripital force).
DG

I want to get some of that "horizontal component of life." That's what it's all about baby.

 

[DGdaPilot]

I want to get some of that "horizontal component of life." That's what it's all about baby.

Hahahaha.....oh, jeez....that one was good for a laugh. Really, I'm not an idiot!

 

[Mmmmmm Burritos]

There's a big thread on this in the training section. There are really only two authentic forces at work here. Lift and weight. The lift acts straight up perpendicular to the lateral axis. The weight always acts to the center of the earth. These forces do not line up in a turn, therefore you break them into components to understand the effects.

The force of lift is called total lift and it has vertical and horizontal components. Vertical fights weight, horizontal makes you change heading. The inertia of the aircraft, also known as centrifugal force reacts (not ACTS, but REacts... centrifugal force isnt really a force) equal and opposite to the horizontal component of lift in a coordinated turn. What the inertia, or centrifugal force, does is cause you to feel the weight of the plane in a different direction than the actual weight force is applied to. Still with me? The centrifugal force deflects the weight vector to the Load Factor vector. This is what you feel. It acts opposite to the total lift component and is equal to it while maintaining altitude in a turn. You feel the weight straight down through the seat, and so does the wings.

Positive G's occur when you stretch the load factor vector by adding more back pressure in the yoke. To maintain constant altitude, you would have to bank more. HCL has nothing to do with load factor... not directly anyway. HCL equals the inertia, which causes load factor to swing away from the weight force. The more HCL, the more bank, the more inertia to overcome, the more load factor, and thus the more back pressure you'll have to apply.

 

[DGdaPilot]

See, the part that screws me up is inertia being equal to HCL. If that was true, then we wouldn't feel ANY G's in even a 60 degree bank turn. But we know that's not true, we feel 2 G's in a 60 degree bank turn. So that obviously means that HCL is greater than inertia. But, I was always taught that VCL is equal and opposite to weight and HCL is equal and opposite to inertia. The average of these forces (vectors) is total lift and load factor. Therefore, load factor and total lift are equal and opposite. See were the confusion? Obviously I'm missing something here.

 

[Speedtree]

You guys are close. You are correct in saying HCL equals inertia. This is not load factor. Load factor is the vector opposite the Total Lift Vector. It is the combination of inertia and aircraft weight. Don't try to get too complicated. KISS remember.


In level flight Lift equals weight. When you introduce bank Lift now breaks into multiple vectors. Draw your diagram with the lift vectors and then add the weight vector which hasn't changed. (I don't focus so much on the inertia vector since it doesn't really mean much to us. it just completes the diagram). Now you have a vertical and horizontal and total lift vector. If your total lift is the same as before you have lost vertical lift and consequently will lose altitude. So you must increase total lift until your vertical lift is equal to what it was before (when it was also total lift) and balances out the weight vector. (constant altitude) Now the vector opposite total lift (draw the other diagonal one) is greater than it was when it was the same as weight (1G) and you have some value of load factor (say 1.5G) which is what you feel. This is not inertia which is in the horizontal but load factor which is in the seat of your pants and opposite lift. The inertia vector doesn't really enter into my discussion at all. You can now move on to accelerated stalls etc.

clear as mud??