‫Welcome back.
‫So let's go back to our airfoil here.
‫Your task was to find the D.H as a function of diesel and in the way you do it is like this.
‫To get the horizontal component of this vector.
‫In other words, to get this component here, you simply have to multiply your Deedes times cosine phi
‫like this.
‫And to get the horizontal component of the DL vector, well, for that you have to take your DL and
‫you have to multiply by Sine and Phi and that's when you will get this component here and then you will
‫add them together and that will be your D.H force vector.
‫So, again, this is the top few of your blade.
‫This blade is rotating at an omega radians per second.
‫This is your differential airfoil element, this is your D.H force factor, which is this one here,
‫and then the distance from the center of rotation till this D.H vector.
‫That's what we're going to call an R.
‫Since we had a small fire angle approximation here, we could say that our sign five would be simply
‫a fire and then our cosine PHI would be one.
‫That means that this D.H vector will be DL Times PHY and plus the D, and by the way, the width of
‫the airfoil is the R and in order to get our differential air resistance moment dequeue, we would have
‫this formula d.h, which is this one times the distance from the center of rotation to the airfoil.
‫So times are.
‫Or you can simply rewrite this equation like this, where this part here, that's this part here.
‫So that's your differential moment due to air resistance because your blade is rotating at Omega radians
‫per second.
‫And now from the previous videos, you know what our differential lift and differential drag was?
‫Just to be clear, D.H is in Newtons and dequeue is in Newton meters.
‫And so now we are going to rewrite this dequeue in this way so you can write it out like this.
‫This portion here.
‫That would be.
‫DL Times, Sefi, and this portion here would be your DEEDI and that are here, that's, of course your
‫aunt here.
‫That's the distance.
‫You can do some factoring and you'll end up in this form here.
‫And note that now I've put this R into the brackets.
‫So that's why now instead of R squared, you have R cubed here and now in order to get our total q our
‫total air resistance moment, we have to consider each infinitesimal airfoil on this blade.
‫So we have to integrate this thing from zero up until Capital R, so this side will be from zero to
‫Q and this one from zero to R meters.
‫So as your R goes from zero meters to capital R meters, you take each differential airfoil element
‫on this blade.
‫You compute the differential moment for the specific blade and then you move onto the next differential
‫blade and then as you scan through the blade, you will add them all up continuously or accumulatively,
‫which is essentially what an integral is.
‫In other words, if you're D-R was here instead, then you would be computing the area under the curve
‫of this function here.
‫And that's integration.
‫Now, in addition, since Armorer has two blades, then we're going to put two here in order to get
‫the total air resistance moment for the entire model, taking into account both blades.
‫So I'm just going to put here and one.
‫If we do that, we can cancel out these TOS here.
‫And so the left side will be queues up and one equals and then I'm going to take some stuff out of the
‫integral, like we talked about before.
‫So I'm going to take an Omega squared and the air density out of the integral and inside the integral.
‫You will have everything else.
‫And so this Kyuss up and one that's your total air resistance moment per motor with two blades.
‫So simply a cube would be for one blade, but Kyuss up and one would be for one more with two blades.
‫And now the moment that the drone applies to the motor is then like this.
‫Ms.
‫D m equals minus Q, sub M and remember this M sub D.M. and put one because it's four more one.
‫That's your talk for M one.
‫So your MS up D.M. one equals and I'm going to put here Omega squared and then I'm going to put here
‫minus one, the air density.
‫The integral C times are cubed, and then in the brackets you have the lift coefficient times PHI plus
‫the drag coefficient and then these are your differential width of your airfoil.
‫And why did I put this minus one here?
‫Well, that's just to account for this thing, right?
‫And now I'm just going to say that this entire thing here, it's C, sub Q and there you go, you now
‫have an expression for the moment that is applied from the drone to the more.
‫And you can also write it out like this, Ms.
‫D.M. One equals CQ Times Omega squared, and since we're dealing with more one than this would be Omega
‫one squared.
‫And I should put here on one squared as well.
‫And also here and even here.
‫But here we just worked in general variables.
‫So I'm just going to leave Omega's like this and again you can find this constant C subcu either by
‫integrating these equations or people also determined it experimentally.
‫This C subcu can be called a torque factor and this torque factor has a different value from the thrust
‫factor that we had before C sub T..
‫So these are two different things, but both total thrust promotor and told moment that is applied to
‫the more by the drone.
‫Both of them have Omega squared in it.
‫So the thrust force was the thrust factor times omegle, one squared, and now the torque applied to
‫the motor equals C subcu times omegle one squared.
‫And now we can find our EUFOR and we're going to do that in the next video.
‫So thank you very much.