I have good news and bad news.
First, the good news.
It is very simple to understand quadcopter frame sizes. It’s a single measurement that is standard for any quadcopter and it gives a good number to compare the size of drones. More on that below …
Now, the bad news.
Things get more complicated when people start using the terms mini, micro, nano, etc. People seem to just use the terms however they want.
In this article I’m going to describe how to measure frame sizes, what different frame sizes are used for, and what some of the various terms mean. Make sure you read to the end where I give some of my thoughts on the best way to characterize quadcopter sizes.
How to Measure Quadcopter Size
The only thing here is that sometimes manufacturers round up or down. So they might call it a 180 frame but really it’s a 175 mm from motor to motor. Not a huge deal unless you’re super picky about details like that.
The hobby has informally adopted various adjectives to describe different sized frames. In rough order of size they are nano, micro, mini, medium and large. The problem here is nobody uses the same words for the same frame sizes.
RC Groups has different forums for micro quads and mini quads. In their descriptions, they say that the micro forum is for “Discussions about 15cm and smaller size multirotor drones” while the mini forum is for “Discussions about 15cm to 30cm size multirotor drones.”
That’s a good start for a definition but they don’t say anything about nano quadcopters or anything larger than 300 mm.
Examples of nano drones are the Cheerson CX-10, the Syma X12 and the Estes Proto X. These are all lower than 100 mm frame sizes. So perhaps the micro prefix should be defined as 100 mm to 150 mm. And nano can be defined as less than 100 mm.
This fits with the definitions that a lot of people use. For example, the Tiny Whoop, which has a frame size of 110 mm is generally called a micro quadcopter.
But the Eachine E010, which is generally considered a cheaper alternative to the Tiny Whoop, is called a mini quadcopter by Banggood and Amazon. So there’s some inconsistency.
Not a huge deal but if somebody’s talking about the latest mini quad from some company, you don’t necessarily know what size they are talking about.
What the Experts Say
I reached out to a number of people to see if we could come to some consensus on these terms.
|RC Groups||Ryan Harrell||Joshua Bardwell||UAVFutures (Stew)|
|Nano||–||80 – 100 mm||–||Small toys|
|Micro||150 mm or less||120 – 160 mm||90 – 180 mm||1″ props|
|Mini||150 – 300 mm||170 – 280 mm||190 – 250 mm||2″ – 4″ props|
Obviously there are differences here, too. Interesting to note that in my email exchange with Joshua, he also talked about prop size but he converted prop sizes to the equivalent frame sizes. For Joshua, quadcopters with 1″ and 2″ props are similar enough that he considered both of those to be Micro while quadcopters with 3″ and 4″ props are similar and are Mini.
I’ll have more to say on the relationship between frame size and prop size below …
Frame Sizes by Function
Another way to classify quadcopters is based on what you are going to do with them. Most people who are into FPV racing don’t necessarily have a drone for aerial cinematography so they might not think very often about the different frame sizes and what you use them for.
FPV Racing Classes
If you get into FPV racing and join a league, they are going to have different classes based, generally, on the size of your quadcopter. For example, here is how MultiGP structures their different classes.
|Class||Frame||Prop (Max)||Weight (Max)||Battery (Max)|
|Tiny Whoop||No Limit||31 mm||35 g||1s lipo|
|Micro||No Limit||66 mm||150 g||2s lipo|
|3s||305 mm||6″ (152 mm)||800 g||3s lipo|
|4s||305 mm||6″ (152 mm)||800 g||4s lipo|
|Open||No Limit||No Limit||800 g||No Limit|
They also have some other criteria about things like video transmitter power that I didn’t include in the table above.
MultiGP structures their classes mainly by battery size. Everything else – frame size, prop size, and weight – looks like it is just scaled appropriately for the given battery voltage. And that makes sense because if you are racing, you want to make sure everybody is on even ground when it comes to the source of power.
Drones that are used for aerial cinematography are generally bigger than mini-quads because they have to carry more stuff. They are usually equipped with a camera and gimble. The DJI Phantom 4 has a frame size of 350 mm. You probably wouldn’t want to go too much smaller than this if you plan on using your drone for high quality pictures and video.
Indoor flying typically requires small quads. This is both for the sake of space and safety. Because of it’s physical size, it’s much easier to navigate a Tiny Whoop through a small apartment than trying to fly a 4s racing quad through the same area.
Additionally, you are much less likely to injure your wife, your mom, or your cat with 1″ props than 5″ props.
Final Thoughts on Quadcopter Sizes
After talking to a number of people and thinking this through, I think the best way to talk about quadcopter size is to talk about prop size. Propellers provide a good lower limit to how big your frame has to be.
For example, if your props are 3″, mathematically the smallest your frame size can be is 107.8 mm (and you thought the Pythagorean theorem would never come in handy after high school!). Realistically, it has to be even bigger than that or because the props are touching at that fame size.
Here’s one last chart for this article. It relates propeller size to the minimum frame size needed for that prop. I rounded all frame sizes up to the nearest 5 mm.
|Prop Size||Min. Frame Size|
So in the future, I will probably talk about prop sizes rather than frame sizes. Adjectives like mini and micro are still useful, I think, but there is some risk of miscommunication when using them.