Lift, Coefficient of Lift

This video consists of the following :
Why is lift generated?
Lift Coefficient
Lift formula
Coefficient of Lift and Angle of Attack Graph
Effect of high lift devices
Cases of the Lift Equation
Stalling angle
TAS, IAS variation
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• Drag, Coefficient of D...
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Cheers and Happy landings! :)

[@karthikeyanbalasubramanian8142]

The best video on Aerodynamics till date ! Kudos ! Clear accent and lucid explanation ! Keep it up !

[@poh]

Thank you

[@poh]

I will be uploading in few days. Need some time to make these videos. Been busy. :)

[@smilenhustle459]

Great work, great content keep up the great work!

[@EvaGolubinska]

Thank you for these vids. Very helpful!!

[@GolyaGergely]

Thanks for sharing this. It's a really good one. Is the stated CLMax always 1.52 or it varies with s, rho, v, W?

[@marshallhyasi6213]

Amazing work, Thank you and keep these vids coming!

[@poh]

Thank you

[@epicghost4085]

This is very good. I’m basic when it comes to physics of any form but you make it quite simplistic and able for persons such as myself to understand. Thank you so much!!!

[@poh]

You're welcome!

[@nathanielho7219]

Can you upload a video about the pressure settings? I'm a bit confused about it. Thank you in advance

[@rishirajchugh100]

your videos are really helpful. great job. in your lift and coefficient of lift video u said at 40000 ft density is 1/4. So to mantain lift TAS should be 4 times. I think it should be twice as TAS is a square function.

[@poh]

Firstly thanks a lot for the appreciation! :) And yess, I cross checked that, its a good error that you have pointed out. TAS is V^2 so yeah twice of TAS will give it four times. Perfect. Thanks on that! :)

[@Gryronaut]

I really enjoy your videos and attitude towards teaching. Good job.

[@poh]

Thank you!

[@gensyed]

Thank you for the refresher course. The last bit there, I think you meant to say High Altitude density and not High density altitude.

[@himanshuahuja5684]

till i saw this video i had so many confusions...thanku so much for making it so clear and easy to understand... Respect Regards

[@poh]

+Himanshu Ahuja Ah. Welcome. My pleasure, glad it helped you. yeah will be uploading stability video next. Stay subscribed and stay tuned.! :)

[@Hussain-by8ct]

Nice video sir u explained perfectly all concept related to lift now I remember❤️💓tnx u sir for ur best vdo

[@obasaran35]

You are great mate! Thank you.

[@poh]

+Onur Basaran Thanks and welcome 🙂

[@engrhaseeb8791]

SIR U R GREAT .....THE U TEACH IS AXM AND EASY M REALY MOTIVATED WITH UR WAY OF TEACHING .....THANK YOU SIR

[@poh]

You're welcome

[@shadabbehmand5865]

Thank you It was great . Keep it up

[@poh]

You're welcome!

[@rashmiranjannayak3251]

Very good presentation of theory. Thank you.

[@poh]

+Rashmi Ranjan Nayak Thank you!

[@Realfoodreallife]

Very nice video...I m able to understand all the terms clearly...above all my basics are improving...So, Thank u so much for making such informative videos...and keep doing the same in future as well 😊👍🏼

[@poh]

+Dolridge Rumao You're welcome! 🙂

[@Realfoodreallife]

Planes Over Head, u mentioned at the end of this video that high altitude density will result in poor performance...but the density vary's with respect to altitude...can u explain it ??

[@lukebates7354]

If you double your airspeed your drag will be squared that, for example if my air speed is doubled to 4kn my drag will be 16kn

[@umisalmah9492]

so helpful, thank you very much :)

[@poh]

Welcome! Stay tuned for more! :)

[@karenlee2871]

May I ask if the +ve sign at the leading edge refers to the dynamic pressure? Im confused with the 16 degrees AOA. Does it mean that the aerofoil stalls because of a reverse pressure differential or because the downwash is not completed with the flow stream? Also, could you please explain how does Bernuelli's principle of total pressure (unchanged) = static + dynamic apply between AOA 14 degrees and 16 degrees. I really dont get it.

[@poh]

Dynamic Pressure is IAS. The positive sign does NOT refer to dynamic pressure. It refers to aerodynamic pressure. Both are two different things. At angles of attack at and higher than approximately 16 degrees, the extremely steep adverse pressure gradient prevents air that is flowing over the top surface from following the aerofoil contour and the previously smooth streamline flow will separate from the surface, causing the low pressure area on the top of the section to suddenly collapse. And as far as I know and believe, and 14 degrees to 16 degrees is concerned, it is the time when the positive aerodynamic pressure starts moving under the wing and at 16 it is almost completely under the wing and leading to a stall. Between 14-16 the theorem is applicable normally. But at 16 it breaks off and causes a disruption. I hope this would have cleared your doubts.

[@lucille24]

Thank you very much, so easy to understand.

[@poh]

You're welcome

[@girishkv1785]

Best video.. very informative.. 👍👍 How lift is generated?? Is there any detailed video on this from you sir?

[@Captain_Rhodes]

exelent video. thanks very much

[@poh]

+Captain Rhodes Welcome! Hope it was a good learning experience! :)

[@moeenuddinsaiyed1586]

best explanation ever !!!

[@poh]

Thank you!

[@shamee33]

superb.. i have one request..can u tell me about TAS and IAS in detail.. plzz

[@poh]

+Sam Kratos Thanks, and yeah will upload soon.. stay subscribed! :)

[@shamee33]

Pleasure..N waiting..;)

[@rushwolf9360]

Can someone help me with this question A moderate speed aircraft moving at a speed of 13 ms-1 whose wing span and aspect ratio is 150 cm and 5 respectively. Assuming suitable wing loading and density of air calculate the lift generated by the wing at cruise speed. [Take g = 10 m/s2].

[@alaaovichbayazzed3860]

A general aviation aircraft, with a wing surface area of 18 square metres, flies at sea level with a speed of 180 kilometres per hour. Its lift curve is shown below. Given that lift equals weight for this aircraft and that the aircraft flies at an 8 degree angle of attack, what is its mass (in kilograms)? can you help me with solving this exercise?

[@19Koty96]

step one, convert the speed to m/s step two, find your CL (or Cy, also marked that way) - you look into the graph and you read value for 8° AoA step three, find air density at sea level in base units multiply: the Cy you've gotten, wing surface area (18 m^2), air density, square of speed (in meters per second!) you have gotten the lift. Now use Newton's first law, F=a*m. You get that you need to divide the lift you've gotten by gravity acceleration (approx 9.8 m.s^-2) - and you get weight in kilograms a bit too late, I know ^^;

[@surajmahendraramraj3870]

@planes over head did you had glasses (specs) at that time?

[@poh]

Yes

[@eyerusalemkidane7595]

thx capitan keep it up!

[@SandeshBaheti]

Thanks! My pleasure!

[@sohaibalam4168]

Nice job sir :)

[@poh]

+Sohaib Alam Thanks a lot :)

[@tristanquinn1123]

I never knew Virat Kohli had a pilots license 😂. But your explaining is tops thank you for that👌

[@poh]

Lol what? Thank you

[@FuadPhenomenon]

What is the unit for L? And, in order for the equation to work, can we out the AOA value in degrees?

[@poh]

From a pilots perspective we really do not need to know that. But Lift is a force, so its supposed to be Newtons.

[@FuadPhenomenon]

@@poh So if i have a wing with AOA of 9 degrees, may I put 9 in the CL for the formula to work?

[@poh]

I doubt it'll be that direct because the units may not balance on both sides. It'll need to be calibrated! Equation is only for understanding purposes!

[@SaurabhKumar-hr7fn]

What is the difference between high and low camber? Are we referring to the thickness of the aerofoil?

[@poh]

I haven't heard about those terms. But there are terms like upper camber, lower camber, positive camber and negative camber. Could you cross check on that?

[@FO300118]

You had mentioned that CL max is 1.52..is there a unit associated with the 1.52?

[@poh]

It is coefficient, no units.

[@mohittandel5441]

How can i calculate lift thought the airfoil camber

[@poh]

What?

[@cagdascosgun7229]

I think you forgot yo mention that flaps decrease AoA therefore just before extend them gives us a great visual aid to see airway 😊👌

[@poh]

Lowering the flaps the stalling angle of attack reduces, but CLmax increases. but the effective angle of attack increases which helps in generating lift even at lower speeds.

[@gensyed]

Simply put - Flaps increases lift and also drag, therefore you can reduce your AOA to maintain the same flight profile but at increased power to maintain speed. In landing profile, it provides better runway view from cockpit and better throttle response at higher power settings.

[@achintgaur9751]

Thank you 👍👍💐💐💐💐

[@poh]

You're welcome!

[@rchauhan94]

11:40 you said half rho v square is constant, if v square increases, rho decreases, but isn't that a decrease in altitude then ?

[@poh]

Yes it is drop in altitude! What it means is if you descend at constant IAS, your TAS will increase.

[@hiramaysikdar]

what you mentioned here does that satisfy no 4 condition? If IAS is constant and TAS is increasing then rho has to be decreased.thats something satisfies your condition no 4. plz make it clear

[@NarenderSingh-wb4vt]

Awesome

[@poh]

Thank you!

[@joelhallin9663]

Do you mean proportional, nought perpendicular, correct me if I'm wrong.

[@poh]

At what point?

[@talkpilot2851]

Hi, this has been so helpful as I have been preparing for frozen ATPL and airline interviews, can you please please help me with the chapter on stability(aerodynamics) shockwave expansion wave and mach crit.. whenever possible .. look forward to your reply thanks..

[@poh]

Talk Pilot Hey, Firstly Thanks! Glad it helped little bit also! and well yeah I'm working on it, been little busy. Will try to upload asap. Subscribe to stay updated on the latest upload! Thanks again! Cheers! And share it :)

[@talkpilot2851]

Thanks a lot will look forward to our videos..I can start studying only after u upload .,,I have tried many books but this is the best..,I have recommended it to all my students as well.,keep up the good work happy landings

[@poh]

Thanks once again! :) Actually right now busy with my Multi Engine Endorsement so unable to make videos and upload! But will get back to this soon!

[@talkpilot2851]

Ok great tc

[@vivekkumarsha4437]

can anyone help me with this question Q)Coefficient of lift CLfor an aircraft? A- keeps on increasing with speed B- become study or constant in supersonic regime of operation C- is always constant for a type of aircraft all speeds D- keeps on wearing in a linear manner

[@orangetech8419]

Hey can CL be less than 1 like 0.0199?

[@poh]

Yes its matter of wing design actually. Any drag creating surface will have those kind of CL

[@mradithya1996]

at 15mins 28 seconds u mentioned the lift to be constant. is the body still rising at a constant rate or is lift zero?

[@poh]

It means the aircraft is rising at a constant rate.

[@mradithya1996]

So it rises to a certain point until all the forces are in equilibrium? Thanks

[@poh]

Yup! beyond that Lift is lost which is termed as a stall.

[@mradithya1996]

Thanks

[@poh]

+Adithya Athreya You're welcome.

[@hellosiri1483]

please explain pressure altitude and density altitude...........

[@gensyed]

The term should have been High Altitude density...

[@kanwarindersandhu1]

How is TAS> IAS at >MSL and TAS

[@poh]

As you are flying above MSL, you are moving towards air with lower density and pressure. As this happens, you have to fly faster because now air is thinner, more air is needed for the engine to continue to perform. So your true air speed is greater than your indicated. Vice versa for below MSL.

[@SanthoshKumar-bm9kh]

how to find out the surface area for any airfoil ? please help

[@poh]

+Santhosh Kumar Multiply the wingspan by the chord to get the surface area of the wing

[@SanthoshKumar-bm9kh]

+DGCA Technical thank you. can you help with the analysis of airfoils in ANSYS ?

[@ngonikenyaditswe704]

gud boi

[@austin.lovell]

How do you find the Lift Coefficient without Lift?

[@poh]

Lift coefficient is given by the manufacturer for a particular configuration. Not for pilots to calculate.

[@19Koty96]

Though it can be reverse-calculated from stall speeds, CL_max that is. A bit complicated, but can be done. As for CL_0, yeah - no real way of telling apart from documentation. Can really be anything. From positive values, through zero, to negative. Not that it'd be practical, but technically possible.

[@gensyed]

With all other values in the formula for lift has values greater than zero and without lift - The Coefficient of lift will be zero, because zero is equal to zero. Coefficient of lift is a number factoring the ability and efficiency of the wing to generate lift at various AOA and speeds.

[@saiprasadmohanty8339]

S is not surface area it's wing plan form area and there's a difference between those two l

[@poh]

The wings are the ones generating lift, when I talk about surface area, its obvious it corresponds to wing plan form area only. The fuselage is not really generating lift, so it will not include in this surface area.

[@himanshuahuja5684]

please upload something for Center of gravity as well...thanks

[@romashavi7944]

how high density alltitude gives poor performance

[@poh]

Density altitude is pressure altitude corrected for nonstandard temperature. As temperature and altitude increase, air density decreases. In a sense, it's the altitude at which the airplane "feels" its flying. So basically if the aircraft is feeling that is it flying at a higher level than it actually is, then it thinks that there is less air density i.e., air molecules and hence there is less lift generated and this leads to poor performance. High density altitude means you are standing at a level where density of air is equal to a level higher than your actual true level, therefore your air density is less and loss of performance occurs.

[@gensyed]

@@poh Correction: The term should have been High Altitude density...

[@surajmahendraramraj3870]

thank you soo much this lesson really helped me.

[@poh]

You're welcome