Open Discussion about Realistic Dynamics?

News & General Discussion
1

Greetings and G’day!

My first Topic and overall Post to the Unity Community, I do believe!

I’m really into Logic-based Development, so I can give most things 2min t-o 2hrs of thought and come to my own conclusions. My doubts will always persist however, until I get confirmation from someone who either specializes in this area, or is simply smarter.

If my suppositions are correct, please confirm. If not, please enlighten me if you care to take the time and effort.

I’m working on a Fantasy/Sci-fi Tactical Combat Racer. As of now, my interest is fixed on Aerodynamic Theory and Applied Design.

Here is the first “Problem”…

Category: Forward Movement + Lifting Planes
Equation: unspecific Lifting Planes are angled forward/up at 45degrees = ?
Additional Info: LPs have no special aerodynamic features, are simply flat or slightly rounded, with a “cutting” edge; equation does not factor in any other dynamics(speed, weight, drag/exposure, ect.).
My Conclusion: This provides 100% of the Lift ratio possible and 50% of the Braking…?

Once I feel I’m standing on solid footing with an Applied Design Theory, I’ll consider Editing/Updating this origin Post with another one. I’m sure I can come up with a few dozen or so scenarios about Dynamics which have to do with my Game specifically. And please feel free to Post Your Own “equations” in Replies and I’ll Edit them into this origin Post(but only if you ask me to?).

Cheers!
~ W_D

2

ummm… what?

are you talking about advanced physics stuff like how race cars lift off the ground on fast turns so they have fins to keep them down?

3

I think it’s a thought experiment of sorts around a physical model with a plane exposed to an airstream and the forces acting on it.

If that’s the case, I’ve done something similar here (which did end up causing an infamous but funny bug, but that’s besides the point) for KSP.

So, given a flat plane set at a 45° pitch angle to the airstream, you postulate it should experience 100% lift force (from deflection, max force being a factor of airspeed, incidence angle and something to relate the plane area to the force exerted), and also 50% of the total drag force, considering the sides are of negligible surface area and as such, total drag is dependent on how perpendicular the plane is to the airstream.

That reasoning is fine, but there are a few issues.

You’re choosing to model lift and drag as separate forces acting in specific directions, like those flight school 101 handbook diagrams show, but deflection lift and drag are actually the same force, from the airflow pushing on the surface.

Consider the case of the plane being completely perpendicular. In such a case you’d have no lift at all, but 100% drag. Or is it full lift, only the lift vector is also pointing towards the same direction as drag?

When the lifting force (which acts perpendicular to the flight surface) is not perpendicular to the velocity vector (because you don’t normally fly at 0° pitch), there is some component of it angled aftwards, acting against the thrust, like drag. This is called lift-induced drag.

There are two ways to model this that I can think of right now: One is to treat drag and lift as completely separate forces, scaling them based on angle of attack. In this case, lift is always applied perpendicular to the incoming airstream, not the plane, and you need to be careful to make sure the sum of drag and lift won’t exceed the total force the airstream can exert (that is, at no point does liftAtAoA+dragAtAoa > maxLift or MaxDrag).

The other option is to apply lift perpendicular to the plane itself. In this case, you’re modeling drag and lift as the same force, and no balancing is required. In this case you’ll probably tune it with a parameter relating plane area to lift force (something like an air viscosity parameter), and you’ll probably still have to set up some minimum drag value to account for skin drag and/or the fact that the leading edge isn’t impossibly thin.

It’s an interesting problem to work out, definitely. Hopefully these ramblings here will be of some help, or possibly just confuse you even further.

In any case, best of luck!

Cheers

4

You’re exactly right about your understanding of what my purpose was for presenting this Physics “equation”!

I can’t honestly claim I was able to grasp everything you said about my options and the explanation of the Physics Principles involved, but it certainly gave me some brainwork to do!

Thanks for the well-wish and the Helpful Response! Cheers to you too!
~ W_D