Good video, but i'd like to add that most aircraft have the CoG in front of the wing/lift for better stability, as you've shown when a gust of wind adds more AoA, in reality, the CoG forward of the lift will cause a downward pitching moment, and the H-Stabilizer adds negative lift to keep the aircraft stable in level flight, and thus avoid high AoA and ultimately stalling in high gust situations.

Thank you!

Thanks! Got something coming soon that I think you'll like :)

Thank you, means a lot!

I didn't know they destroyed the hydraulic lines as well, that's interesting. Yeah that definitely wouldn't have helped with the c.g. shift. Thanks!

Thank you so much for this comment and your encouragement. Glad to have you onboard, have a good one!

Thanks for your kindness and honesty! Glad to have you on board :)

@@FlyByMax The pleasure is completely mine, your videos are well structored, the script is flawless and with no interruptions (like stutters or gaps of silence between sentences). Keep it up, you're certainly in the right way.

Thanks! This really helps to keep this up. Have a good one :)

You're absolutely right about the counter force neither being a pitch up or a pitch down! I made a small mistake in the video, Cma is actually equal to Delta T / Delta alpha, so if Cma is zero then it means that T will not increase or decrease for a change in alpha (exactly as you got right). This doesn't make the aircraft too stable though, it actually makes it neutrally stable. An aircraft that is too stable would have an infinite (negative) Cma, since then even a small alpha would cause a huge counter-reaction. Hope this makes sense, and great job on your reasoning!

@@FlyByMax i am a high-school student (in class 10) and i am interested a lot in maths and physics. your explanation was great, even a class 10 student could easily understand! great job, i know you will succeed!

Thank you, means a lot!

Thanks so much! Good luck with your gliding training, flying gliders got me into engineering and flight simulators in the first place, I had so much fun and I'm sure you will too :)

@@FlyByMax thanks :)

That sounds awesome! I thought about trying to program a flight simulator as well, it's a huge challenge. I'm still learning a lot about stability and control algorithms, so I know the feeling of being out of your depth :)

@@FlyByMax Oh my god that is amazing! I have also just begun writing a global flight simulator. I've almost finished the scenery engine. I came to your channel for understanding flight physics. Thank you so much for the videos.

Hi! Thanks for your comment. I do have sources which show the possibility of the aerodynamic center of the wing being in front of the centre of gravity. I also have a reason for why I decided to show the forces as I did in the video. First and for all, something I did not mention in the video (since it would over-complicate things) is that in my diagrams I assume the lift to be acting through the aerodynamic center (AC) of the wing. This is useful, since you may know that the AC is defined as the location around which the aerodynamic moment does not change with respect to angle of attack. I assume that when you say "center of lift", you are talking about the centre of pressure (COP), which you probably also know moves forward with decreasing angle of attack. You are completely right that for the vast majority of the time, the tail does provide a downward force in most commercial aircraft. The reason I chose to display things as I did in the video, is because this way it becomes extremely clear that the horizontal tail is not optional, but a requirement for stability. Without the tail and if the c.g. was to be in front of the a.c. of the wing, the aircraft would technically be stable if its aerodynamic moment was positive, although marginally (neglecting the de-stabilizing effect of the fuselage). But this was all a bit much to show in the video and would only make things less easy to grasp, which I think is also the reason why these concepts are taught to students the way they are (see sources below). However, I believe that it is a common misconception that the c.g. needs to be in front of the COP/AC of the wing (meaning tail pulling down) for the aircraft to be trimmed and/or stable. It is possible to have a stable, trimmed aircraft where the c.g. is aft of the a.c. You can do the analysis yourself by computing the derivatives, but here are also multiple sources which show similar diagrams of the c.g. being behind the a.c: Cornell University, "Introduction to aircraft stability and control", see diagram on page 26: courses.cit.cornell.edu/mae5070/Caughey_2011_04.pdf TU Delft, part of the course "Introduction to Aerospace Engineering", see 1:18:07 in the lecture "Moments and Axes": ocw.tudelft.nl/course-lectures/1-4-moments-longitudinal-static-stability/ Also see the corresponding handout to the above course: ocw.tudelft.nl/wp-content/uploads/Hand-out-Stability_01.pdf Finally, good ol' wikipedia: en.wikipedia.org/wiki/Longitudinal_static_stability I hope this helps! It's a shame I wasn't able to explain some of this in the video, but unfortunately I had to leave some things out :)

@@FlyByMax wow! Thanks for this in depth answer - I will have a close look on the provided material :)

You are absolutely right. It would be neither :) not stable or unstable, just neutral! Great job!

@@FlyByMax thanks and I had to think like this to the wing it wants to pitch up and pitch down the plane and you said that ' CMA was to be -1 not positive so it can't be 0 just I don't know

Hi! Thanks for your comment :) Cma is equal to the change in T (delta T in the video) divided by the disturbance in angle of attack, delta alpha. To explain it in more simple terms, Cma is a number that tells you how stable (or unstable) the aircraft is, because Cma says something about how much stabilizing torque the aircraft generates (7:13). So if Cma is zero, that means almost no restoring torque (delta T) is being generated, meaning that the aircraft is not very stable. If Cma would be largely negative, then that would mean that the aircraft's design produces a big torque delta T, making it very stable. Hope this helps!

@@FlyByMax Thank you so much my man! your the best!

The lift vector acting upwards (center of pressure) is acting behind of the center of gravity. This creates a pitch down moment, counteracted by the tailplane.

@@Tortilla196 thanks for your response - you should say exactly that at 2:42. A step is clearly missing here.