This very well should be my last post on this topic.
I doubt we'll be that lucky.
You haven't made any technical points, you don't know the aerodynamics of the aircraft, much like myself, and therefore cannot support any "technical" evidence. We all have only used basic theories of aerodynamics to speculate on the ability of the aircraft to reduce drag given the hypothetical posted by OP. I didn't come in here asserting qualifications, I simply stated my career, where we use wind tunnels on a weekly basis. I've made it perfectly clear that I don't claim to have a higher or greater opinion than any of you, nor am I asserting what my position as the ultimate truth. I even mentioned that I am relatively new to drones as a whole, I grew up flying other types of RC. So please refrain from putting words in my mouth.
It's quite fascinating that you feel able to claim that I haven't made any technical points. I provided a mathematical proof that you are incorrect - how does it get more technical than that? Oh I forgot - it has no numbers so it must be wrong.
This has come down to pointing out that you can not conclusively state your opinion as true.
I didn't present an opinion - I posited an argued proof. Anyone with any technical education would understand the difference. And if you disagreed with either the maths or the underlying assumptions then you could have disputed them. You made no effort at all to do that.
I've made plenty of observations but you choose to ignore and/or pretend that I didn't.
No - you have made random assertions, not observations, unless you count watching YouTube as an observation. And you didn't even string those assertions together to form a cogent argument.
Surface area increase is relatively proportional to drag increase. If you double a surface area of a craft, you have doubled the drag. If you decrease the surface area exposed by half, you have, for all intents and purposes, halved the amount of drag resistance on the craft.
Agreed, and drag is one factor limiting airspeed. But that's irrelevant to the question of whether you can ever make progress by zig-zagging into a headwind that exceeds your maximum airspeed, because for a given aircraft, maximum airspeed is fixed. Drag is not an independent variable.
Drag and ground speed are inversely proportional.
No they are not, trivially so, because ground velocity is air velocity minus wind velocity. If for no other reason than that wind speed in any given situation is an independent constant that does not depend in any way on drag, proportionality is therefore impossible. And airspeed is only drag limited, so only maximum airspeed is a function of drag - up to that point drag is offset by thrust.
Until you have tested the resistance of the craft at the various positions during flight in a wind tunnel, you do not have technical data, you have speculation. If flying pitched/rolled at an angle reduces surface area, you have reduced drag.
For a given airframe, airspeed is a function of tilt, and weakly of pitch and roll independently. Drag is a function of the same parameters. You don't need a wind tunnel to determine that relationship - all you need to do is record velocity as a function of tilt (or pitch and roll). And because of that, and the aircraft specifications, we already know maximum tilt and maximum airspeed. So the way that drag contributed to that is moot - we already know the maximum airspeed which is what we need to calculate motion in a given wind field.
If you reduce drag sufficiently, you may increase ground speed. I cant make this any simpler than that.
You maybe could not make it simpler, but you could at least make it correct. The aircraft drag coefficient, as a function of aircraft attitude, is not negotiable. It's what determines the maximum airspeed. We already know the maximum airspeed - it's in the specifications and it's easily confirmed in the logged telemetry.
I now realize that you actually have no clue what this thread is even discussing. It's not a question of whether flying with the motor thrust vector (and thus the aircraft velocity in the atmospheric frame of reference) aligned with other than the aircraft x-axis buys more airspeed - do you not even bother to read discussion threads before wading in. And if you had read and understood the proof I presented it would have been obvious from that too. In fact straight forwards or backwards are marginally better than any form of crabbing - you wouldn't know that without looking at flight telemetry, but it's completely irrelevant anyway. This discussion is about whether flying a zigzag course allows you to make better progress into the wind, a superficially similar concept to tacking a boat but actually a completely different mechanism when only operating in one working medium. It doesn't, and that's what I demonstrated in the earlier proof. Did you not read it, or did you simply not understand it at all?