One thing I'd add to this to better explain it: define "break" more clearly! Sometimes, people refer to the stall as the "break," so this can be confusing to students. I would say, "you'll stall before structural damage to the plane can occur."
I like the video series. I know it's meant to be educational and targeted especially toward student pilots, but I think you can cut back a tiny bit on the babysitter tone. Other than that, I'm loving that concise and to-the-point way that I've come to love from Boldmethod. Keep it up!
A complete generalisation, take a look at the AFM for an Extra 300, Va at the lighter aerobatic weight is higher than at the lower Utility weight. It depends on numerous variables, and in the case of aircraft with fuel carried in the fuselage it may well increase with reducing weight as the wing root bending moments reduce, however, this depends on many other factors. I know the exams all want you to say it reduces, but that is NOT always the case and is an example of how giving the answer they want to hear, whether the FAA, CASA or some other regulator, doesn’t lead to an actual understanding of what is happening.
Reducing Va with reduced weight, or mass, will stop you from exceeding the certified g limit. However, don’t worry about breaking the aeroplane. If Va is 110 knots for a certified 4G and 2,400lbs MAUW aeroplane then it’s been designed to stall when the wing is producing 9,600lbs of lift; and so not break. So you have have a 9,600lb wing. If you get airborne at 1,600lbs, fly at 110kts and pull to CL max you’ll still only get 9,600lbs of lift before you stall, and so the wing won’t break, just you’ll be pulling more Gs! The only thing is you’re going to have to explain why you exceeded the certified G limit, but the wings will not fold above you. In fact, if you got airborne on your wet-winged GA aeroplane solo, with no baggage and even the chocks and steering arm left on the ground you’d be very unlikely to break anything due to change in bending moments. Hence aeroplanes from Airbus A350s and Boeing 787s to fighter jets leaving the wings wet and using fuselage fuel first to reduce the stress on the wings. There are older fighters out there that have hundreds of g-limits to cope with different weights and fits. I can think of one that had over 400 positive g-limits varying from +2.5G NO to 8.6G NE . It varied with fit, weight, speed, subsonic or supersonic, as well as flap and wing position. Even most GA aeroplanes have a couple of limits depending on weight, 3.8G increasing to 4.4G when you reduce to the utility category weight. Remember there’s also a 1.5 G safety factor. Notwithstanding all I’ve written. KEEP TO THE LIMITS, they’ll keep you safe and last time I checked Cessnas and Diamonds don’t list Martin Baker on the options list. However, nice video which needs to be regarded for exams and still keeps you extra safe by not over ‘G-ing’ your aeroplane. Sorry, I was looking for something else, saw this and couldn’t resist. I’ll get back in my box . Keep up the good work.
One thing someone said once really stuck with me. All parts of the airplane are designed with the G limit in mind. If the plane is light with only you in it, it will reduce stress on the wings. *But YOU are still 4x as heavy.* It's no good if the wing is perfectly intact but you and your seat punch through the bottom of the fuselage because you laid 5G onto that sheet aluminum floor.
So hard for me to comprehend this but basically you just pulling more Gs at a lower weight therefore the forces (airspeed) that will break the plane are lower because the Gs are higher also the Va is lower bc you will stall at a lower speed because the point from level flight to critical angle of attack is greater and to get there without breaking the plane you need to be flying slower is this correct?
Damage to the frame, and yes this can include "break the wings off", it has happened many times, though it can also be less catastrophic bending of parts.
The wings should be able to handle more Gs when the airplane is lighter because one G at 1900lbs is less force than one G at 2300lbs, correct? So am I correct to say that this theory is simplified to assume that the value of one G is the same amount of force whether you are at 1900lbs or 2300lbs?
Yes, if the limiting factor is the wing/fuselage connection. However, load factor takes other things into account like the engine mounts, battery mounts, etc. A lighter aircraft will have a higher load factor at the same AoA/airspeed, which results in a greater force on fixed weight components like the passenger. You are correct though that the total force on the wings isn't directly tied to load factor.
Va has nothing to do with your cruise angle of attack. It's related to the Lift force at critical AoA at a certain airspeed. At any given airspeed the force on the wings will be the same at the same angle of attack. If the plane is heavier, the load factor will be less at the same airspeed. This means that other components such as the engine or battery, which are a fixed weight, experience more acceleration when the aircraft weighs less at the same AoA.
1. When an aircraft is heavier, a given amount of force generated by the wings results in a lower G-load and thus less force on components of fixed weight - like the battery or engine. Therefore, if these items are the items of concern, an aircraft’s maneuvering speed will increase with an increase in weight. 2. If the aircraft’s wings ripping off are the limiting factor - the weak point - then the maneuvering speed would not increase with an increase in weight as the force on the wings is the same at a given airspeed and AoA; it would actually go down as weight increased (the stress on the wing/fuselage connection would depend on total weight and total aerodynamic force - like pulling something apart. However, moments also come in to play here - if the extra weight is added in the wings fuel tanks, for example, the stress on the wing/fuselage connection may decrease with an increase in weight). So put differently, if we increase weight by adding it to the wing, maneuvering speed should go up, but if we increase weight by adding it to the fuselage, maneuvering speed should go down.
"wrong" when you are heavy or light with the same speed, forces on the wings ARE THE SAME. but whole airplane feels more G`s. So where is the problem if wings don't see the difference? one of big problem is a engine mount feels stronger forces and can brake up, and we love keeping our engine in the proper place. airplane without engine.... like cessna 172 glider edition. 😂
Yeah, no. Your idea falls apart when you consider an airplane, of *infinite* mass, flying a *_ballistic path_* , and then "pulls up". The wings pop off. Similarly, if an aircraft had a density of 0.0000000001 pound per cubic foot, because I invented a new structural material called McCrackenite that had all the strength and volume of aluminum, but none of the mass, it would easily make a 1000 g turn without losing its wings. The G meter, in the aircraft, is not a universal measure of the stress in the wing spar, empennage, and engine mount(s). Just as an AoA meter is a better indicator of impending stall, a strain gauge on the spar (etc.) is a better indicator of impending over stress.
One thing I'd add to this to better explain it: define "break" more clearly! Sometimes, people refer to the stall as the "break," so this can be confusing to students. I would say, "you'll stall before structural damage to the plane can occur."
hey Han 👋🏼
Getting ready for a commercial flight test and got a feeling the testing officer is going to ask this one! great explanation!!
Thought that was Swayne in some of the other videos. His Caravan gig in Hawaii sure looks sweet.
I love this video! Ive used it so many times to demonstrate Va to my students - Thanks!
I love your videos! They're very informative and educational.
I’ve been trying to find the formula for ages. Idk why it’s been so hard to find, but thank you!!
Bro your explanations are dope! Way to break it down!
Great concise video! Music is a little too loud and distracting though.
I like the video series. I know it's meant to be educational and targeted especially toward student pilots, but I think you can cut back a tiny bit on the babysitter tone. Other than that, I'm loving that concise and to-the-point way that I've come to love from Boldmethod. Keep it up!
You're crazy, his delivery is hilarious and informative
A complete generalisation, take a look at the AFM for an Extra 300, Va at the lighter aerobatic weight is higher than at the lower Utility weight. It depends on numerous variables, and in the case of aircraft with fuel carried in the fuselage it may well increase with reducing weight as the wing root bending moments reduce, however, this depends on many other factors. I know the exams all want you to say it reduces, but that is NOT always the case and is an example of how giving the answer they want to hear, whether the FAA, CASA or some other regulator, doesn’t lead to an actual understanding of what is happening.
Is this based on power off stall or power oin?
Reducing Va with reduced weight, or mass, will stop you from exceeding the certified g limit. However, don’t worry about breaking the aeroplane. If Va is 110 knots for a certified 4G and 2,400lbs MAUW aeroplane then it’s been designed to stall when the wing is producing 9,600lbs of lift; and so not break. So you have have a 9,600lb wing. If you get airborne at 1,600lbs, fly at 110kts and pull to CL max you’ll still only get 9,600lbs of lift before you stall, and so the wing won’t break, just you’ll be pulling more Gs! The only thing is you’re going to have to explain why you exceeded the certified G limit, but the wings will not fold above you. In fact, if you got airborne on your wet-winged GA aeroplane solo, with no baggage and even the chocks and steering arm left on the ground you’d be very unlikely to break anything due to change in bending moments. Hence aeroplanes from Airbus A350s and Boeing 787s to fighter jets leaving the wings wet and using fuselage fuel first to reduce the stress on the wings. There are older fighters out there that have hundreds of g-limits to cope with different weights and fits. I can think of one that had over 400 positive g-limits varying from +2.5G NO to 8.6G NE . It varied with fit, weight, speed, subsonic or supersonic, as well as flap and wing position. Even most GA aeroplanes have a couple of limits depending on weight, 3.8G increasing to 4.4G when you reduce to the utility category weight. Remember there’s also a 1.5 G safety factor. Notwithstanding all I’ve written. KEEP TO THE LIMITS, they’ll keep you safe and last time I checked Cessnas and Diamonds don’t list Martin Baker on the options list.
However, nice video which needs to be regarded for exams and still keeps you extra safe by not over ‘G-ing’ your aeroplane. Sorry, I was looking for something else, saw this and couldn’t resist. I’ll get back in my box .
Keep up the good work.
One thing someone said once really stuck with me. All parts of the airplane are designed with the G limit in mind. If the plane is light with only you in it, it will reduce stress on the wings. *But YOU are still 4x as heavy.* It's no good if the wing is perfectly intact but you and your seat punch through the bottom of the fuselage because you laid 5G onto that sheet aluminum floor.
@@JETZcorp Ok that actually makes a lot of sense, say the load on the motor mounts to the fuselage would be under higher stress than normal.
Neat!
What's the name of the background music?
Ah, it all makes sense to me! Va, ready... pull! Okay, not really.
#Aviation
So hard for me to comprehend this but basically you just pulling more Gs at a lower weight therefore the forces (airspeed) that will break the plane are lower because the Gs are higher also the Va is lower bc you will stall at a lower speed because the point from level flight to critical angle of attack is greater and to get there without breaking the plane you need to be flying slower is this correct?
Have you been teaching for almost 21 years
What does "break" mean in this context? Break the wings off? Or...
Damage to the frame, and yes this can include "break the wings off", it has happened many times, though it can also be less catastrophic bending of parts.
structural damage.
The wings should be able to handle more Gs when the airplane is lighter because one G at 1900lbs is less force than one G at 2300lbs, correct? So am I correct to say that this theory is simplified to assume that the value of one G is the same amount of force whether you are at 1900lbs or 2300lbs?
Yes, if the limiting factor is the wing/fuselage connection. However, load factor takes other things into account like the engine mounts, battery mounts, etc. A lighter aircraft will have a higher load factor at the same AoA/airspeed, which results in a greater force on fixed weight components like the passenger. You are correct though that the total force on the wings isn't directly tied to load factor.
Great Video! now try blinking ;p
Why would you break before you stall?????
Well, the wings would less likely to break with less weight, but there are structures or equipment other than wings that are vulnerable to Gs.
Va has nothing to do with your cruise angle of attack. It's related to the Lift force at critical AoA at a certain airspeed. At any given airspeed the force on the wings will be the same at the same angle of attack. If the plane is heavier, the load factor will be less at the same airspeed. This means that other components such as the engine or battery, which are a fixed weight, experience more acceleration when the aircraft weighs less at the same AoA.
1. When an aircraft is heavier, a given amount of force generated by the wings results in a lower G-load and thus less force on components of fixed weight - like the battery or engine. Therefore, if these items are the items of concern, an aircraft’s maneuvering speed will increase with an increase in weight.
2. If the aircraft’s wings ripping off are the limiting factor - the weak point - then the maneuvering speed would not increase with an increase in weight as the force on the wings is the same at a given airspeed and AoA; it would actually go down as weight increased (the stress on the wing/fuselage connection would depend on total weight and total aerodynamic force - like pulling something apart. However, moments also come in to play here - if the extra weight is added in the wings fuel tanks, for example, the stress on the wing/fuselage connection may decrease with an increase in weight). So put differently, if we increase weight by adding it to the wing, maneuvering speed should go up, but if we increase weight by adding it to the fuselage, maneuvering speed should go down.
0:40 1:21
Well this didnt explain anything.
That formula is a bit ridiculous. Try 1% reduction in Va for every 2% weight decrease. Much easier to use and remember and gets close enough.
😺😺😺😺
"wrong" when you are heavy or light with the same speed, forces on the wings ARE THE SAME. but whole airplane feels more G`s. So where is the problem if wings don't see the difference? one of big problem is a engine mount feels stronger forces and can brake up, and we love keeping our engine in the proper place. airplane without engine.... like cessna 172 glider edition. 😂
Yeah, no.
Your idea falls apart when you consider an airplane, of *infinite* mass, flying a *_ballistic path_* , and then "pulls up". The wings pop off.
Similarly, if an aircraft had a density of 0.0000000001 pound per cubic foot, because I invented a new structural material called McCrackenite that had all the strength and volume of aluminum, but none of the mass, it would easily make a 1000 g turn without losing its wings.
The G meter, in the aircraft, is not a universal measure of the stress in the wing spar, empennage, and engine mount(s).
Just as an AoA meter is a better indicator of impending stall, a strain gauge on the spar (etc.) is a better indicator of impending over stress.