‫Welcome back.
‫There is one small change that you need to know about, and that change happens here in this support
‫files drawn.
‫So this is your init function.
‫And if you look at your seat and CQ, these are your thrust and drag factors.
‫Then in the previous videos, you saw that these were the values for the thrust and drag factors.
‫Right.
‫And then the units for them were Knewton times second squared and then here Knewton times meters, times
‫second squared.
‫And then in the main file, the place where we defined our initial propellor rotational velocities,
‫the omega's right here before you have here.
‫Three thousand radians per second now.
‫Actually, three thousand radians per second is a very big value.
‫And the reason why it didn't give problems in the simulator was because by mistake, these values were
‫too small.
‫In fact, these values were correct, but the units were not correct.
‫This value here is not in Newton Times.
‫Second squared, it was in Newton over R.P.M. squared.
‫And then this value here for the drag factor.
‫It was not Knewton times Meeta Times second squared, it was Newton Times Meeta over R.P.M. squared.
‫If these units are used, then the thrust and drag factors, they become very small.
‫And since you know that the total thrust equals the thrust factor times and then this some of these
‫angular velocity squared of the propeller's and then your your control moment equals the drag factor
‫and then these terms.
‫Then if this city and CQ, if they become very small and you want to keep your initial you one and initial
‫EUFOR at some kind of level, then that allows you to make those omega's bigger.
‫So due to that unit error and CQ, you were very small and then the Omega's were very big and in the
‫simulation it did not affect the You Want and EUFOR values.
‫They were at normal levels.
‫Only after I had more closely examined the aztek hummingbird's specifications.
‫Then I noticed that no way is propeller's can achieve three thousand radians per second.
‫And then this unit error came out and all I had to do in order to solve the problem was to convert it
‫from these units here to these ESSI units here by multiplying this factor by the original value.
‫So it's the same thing for the thrust factor and for the drag factor that made CTY and CQ bigger and
‫then the normal you one and you four levels could be achieved with the omegle values that are reasonable
‫for this specific drone.
‫And so the minimum omega's the minimum propellor rotational velocities for Ozturk Hummingbird are more
‫or less these ones here.
‫They provide some kind of thrust, but the total thrust will not overcome the weight of the drone.
‫So when the omega's rotate at these values and these values are radians per second, then you will have
‫a drone with rotating propellers.
‫But the drone will be at rest because at these rotational speeds they will not be able to create enough
‫thrust to overcome the weight of the drone.
‫And so how do we convert these units into Newton's second squared and Newton meters second squared?
‫It's actually very easy.
‫So Newton over R.P.M. squared.
‫Now, what is R.P.M.?
‫R.P.M. is rounds per minute like this, but let's call it our Overman and so I can write it down like
‫this.
‫Newton over R squared over min squared.
‫I can also write it down like this.
‫Newton times min squared overwound squared.
‫I can also rewrite it like this Newton.
‫Times, many times, men over our times are.
‫And so in one minute you have 60 seconds, but you had minutes squared, so you have to add one more
‫ratio.
‫And then in one round you have two pie radiance.
‫Right, because around is one circle.
‫It's too pie radians.
‫And again, since we have round squared, then we have to add one more ratio here.
‫And now the minutes cancel out and the rounds cancel out.
‫And so you are left with neutral times, 60 squared, second squared and two pi squared radians squared
‫but radians.
‫It's dimensionless, right.
‫Because what is radians.
‫It's meters over meters.
‫If you have a circle and then you have your circumference and then you have your diameter, then your
‫circumference over diameter will give you pi radians.
‫In other words, it will give you pi meters over meters because the circumference is measured in meters
‫and the diameter of the circle is measured in meters.
‫And so they cancel out and therefore radians is dimensionless.
‫So you can just ignore that.
‫And that's why when you have something in Newton over R.P.M. squared, then if you take that something
‫and you multiply it by 60 over two PI squared, then you will get that quantity in Newton second squared
‫and then will in this case it would be the same thing.
‫It's just you would have had meters here, then meters here, 10 meters here than here and then also
‫here and here.
‫And that's why I multiply these values here by 60 over two pi and all that squared in both cases.
‫And of course, in the latest downloadable file, this has already been modified.
‫So thank you very much.
‫And I'll see you in the next video.