Lesson 28: Reading load factor Charts

Welcome back, everyone! Let’s continue our discussion of how loading affects performance.

How to Read a Load Factor Chart

Now, let’s talk about Load Factor Charts and how they can be extremely useful for pilots. But first, what are load factors?

Remember when we learned that adding weight to a plane means that you have to fly it faster so it won’t fall?  

Well, when a plane is making a turn, that also has the same effect as adding weight to it. 

Cool, and kind of scary, right? 

The same applies to roller coasters. When a roller coaster goes really fast and makes sharp turns, you might feel like you’re twice as heavy than normal! 

This concept is known as a ‘load factor.’ 

That’s the extra push or pull any aircraft feels when it turns, goes up, or goes down quickly.  

It’s like feeling heavier when you spin around fast.

When the drone moves, this force can feel like it’s multiplying the drone’s weight.

So, a load factor of 2 means that the drone feels twice as heavy due to the maneuver.

Understanding load factor is important because it helps drone pilots know what stress your drone can handle, without falling from the sky! 

Luckily, when you get a big, fancy drone, chances are, it will come with a load factor chart.  

This is a way for pilots to know what effect (or weight) moving their aircraft around has, so they can avoid something going terribly wrong.  

Before looking at a Load Factor Chart, let’s explain what it is.

A Load Factor Chart is like a special chart for your drone. It shows how much extra weight (push or pull) your drone feels when it turns or moves really fast.

Are you ready to take a look at one? 

Yikes. It has a bunch of numbers and some strange symbols. But what do you see when you look at it?

If the angle of bank is 60 degrees, then the load factor in G units is double, so it’s twice as heavy. 

Remember that the angle of bank is not just the angle that it’s flying at, but its tilt! Because all aircraft tilts when it flies to the side! 

LF - the extra gravity acting on your drone. Zero- regular gravity 

More than zero, more gravity 

Step 1: If the angle of bank is 45 degrees, what’s the load factor? 

Let’s do one together:

On the test, you’ll get this with extra information about how your drone weighs. 

Multiply the weight by the load factor. The angle it’s moving at is the angle of bank.  

Do one individually: 

Let’s say your drone weighs 20 pounds. It’s going at a 30 degree angle.

How heavy would your drone feel (aka its load factor) if it’s 20 pounds and flying at a 30 degree angle? 

Find 30 degrees 

Find the load factor number next to it to find the load factor 

Multiply weight of drone + that LF number 

Try not to turn at angles after 45 degrees, definitely don’t fly at a 90 degree angle unless you want to break time and space. 

If an airplane weighs 23 pounds, what approximate weight would the airplane structure be required to support during a 60° banked turn while maintaining altitude?

The steeper the angle of bank, the higher the load factor in G-UNITs. 

If the drone is 10 pounds, and you are turning at an angle of bank at 10 degrees, how much weight does your drone need to be able to support that turn?

Weight of drone * Load factor (which is on the same line as the angle of bank) 

The turn acts like the drone weighs 10.15 pounds. 

A load factor chart is a tool that shows how much extra force (added weight) a drone experiences during different maneuvers, like turning, climbing, or descending. 

It helps drone pilots understand the limits of their drone to ensure safe and efficient flight.

By using the chart, pilots can avoid putting too much stress on the drone when flying in different ways.

Knowing this helps us prevent damage and maintain the best performance.

You’re doing great, everyone! Now, let’s talk about how
Load Factor Charts work.

If you look closely at the chart, you’ll see a term called ‘Angle of Bank.’ And when the angle of bank increases, so does the load factor. 

If you look closely at the chart, you’ll see a term called ‘Angle of Bank’ and another one called ‘G-UNIT.’ Let’s decode them!

The Angle of Bank is how much a drone or airplane tilts to the side when it turns. 

Imagine riding a bike and leaning to one side to go around a corner; the angle of bank is like that lean, but for flying.

Your angle of bank is basically how far your drone is leaning to the side during a turn.

If you look at the chart, when the angle of bank increases, so does the load factor.

And, a load factor is measured in G-Units, which represent the force of gravity (or
the weight pressing down) on an object.

A G-unit is a way to measure how much force you feel when something speeds up, slows down, or turns. 

It's named after gravity, which is the force that pulls everything down to the ground.

When you're just standing on the ground, you feel 1 G – this is the regular pull of gravity!

When you’re in a fast car, roller coaster, or airplane, you might feel more Gs – 2-3 times heavier than normal! 

So, when your angle of bank is bigger, your load factor (and G-Units) are bigger.

All that to say, the more your drone leans to the side, the more gravity (weight) is acting on it.

You may have felt something like this in real life! Think about being on a roller coaster or in a car making a sharp turn. How did it feel physically?

That’s right! You probably felt like you were being pushed into your seat. 

This is the same thing that happens to your drone during a sharp turn! Drones need to be built to handle this extra force.

Bravo, everyone! Now, let’s get back to the load factor. 

The load factor tells you how much extra weight the wings of your drone are holding compared to the actual weight of the drone and everything on it. 

In fact, there’s a formula for it! 

The Load Factor equals:

The Total Load Supported by the Wings / Actual Weight of the Aircraft

Load Factor = Total Load Supported by the Wings / Actual Weight of the Aircraft

Another way to say this is:

Load Factor X the actual weight of the Aircraft = Total Load Supported by the Wings

Let’s go through an example to make this clear. 

Suppose you have a drone that weighs 25 pounds and you’re making a 45° turn. 

According to the Load Factor Chart, the load factor for a 45° turn is 1.414.

And at 45° turn, that’s when it starts to change significantly. 

Now, we apply the formula. 

Multiply the load factor (1.414) by the drone’s actual weight (25 pounds).

1.414 x 25 = 35.35 pounds.

So, in a 45° turn, your drone's wings are working harder to hold up more weight than usual.

Remember: multiply the drone’s actual weight by the load factor of the angle of bank, and you’ll see how much weight the drone has to be able to support!

Fixed-Wing Drones and Stalls

And the Critical Angle of Attack! 

Fixed-Wing Drones and Stalls

Great work! And finally, let’s talk about fixed-winged drones.  

During your drone pilot career, you might end up flying a type of drone called a fixed-wing drone. 

And, you might see them be called “unmanned airplanes” – that’s basically what they look like! An airplane without a pilot, crew, or passengers inside.

Fixed-wing drones have a few features that make them pretty unique. 

For example, they have a rudder that controls their yaw. 

That’s when a drone moves side-to-side without tilting!

Different fixed-wing drone models can have very different rudder maneuverability.

If you’re launching a fixed-wing drone on an uphill slope, you’ll need to increase your launch distance to get the drone up into the air.

And finally, fixed-wing drones can run into a major problem called stalls.

A stall happens when a drone’s wings can’t lift it up anymore. It’s stalling!

Ugh… not too good! 

But… why does this happen?

Stalls usually happen when the drone is tilted up or down too much, beyond a certain angle.

Then, the smooth airflow over the wings can get disrupted, causing the drone to start falling.

So, when a drone is titled beyond a certain angle, it creates a stall. And that certain angle has a special name. You won’t believe what it is. 

This special angle is called the critical angle of attack. It sounds like a move in a fighting game or something!

If the pilot tilts the drone beyond this angle – beyond the critical angle of attack – the wings lose their lift, and the drone can't stay level, which means it, too, shall fall. 

The Critical Angle of Attack is the biggest angle that an airplane or drone's wing can tilt into the air and still keep flying. 

If it tilts up too much past that angle, it can’t fly well and might start to fall.

Angle of Attack: how much the wing is tilted up into the air.

Critical Angle: The highest tilt that still works. After that, the wings don’t work

Stall: When the wing tilts too much, it loses its lift and the airplane or drone can start to fall.

Don’t stall, and don’t fall! Know the limits of your drone – especially its critical angle of attack. Don’t tilt your drone beyond it. 

So, remember the term 'critical angle of attack'. This is the angle where the wings can no longer provide lift. It's important for drone pilots to know this, and it might even show up on your test!

And finally, another thing to keep in mind is your drone’s Center of Gravity (CG). If your CG is off, it’s harder to recover from a stall, and generally more difficult to control your drone.

Remember, drone manuals exist for a reason! 

So, always make sure your drone’s weight is balanced correctly, and read the manual to know what and how much it can handle.  

Great work! I see you’re all a few steps closer to becoming a certified drone pilot.