Noise at RC airfields, especially for those near homes and populated areas, poses a big problem. While some RC enthusiast has the luxury of flying in a remote area to enjoy their hobby without restrictions, others must adhere to strict noise policies at their local club. So, how loud are RC planes exactly?
On average, electric RC planes produce noise levels ranging from 40 to 60 dB. Nitro-powered RC planes generate significantly higher noise levels, typically between 70 and 90 dB. RC jets are the loudest, their noise levels exceeding 100 dB.
Although we all love to enjoy our hobby without limits, it’s really important to think about other people. The sounds that we find thrilling, other people see as annoying. As the former U.S. Supreme Court associate justice Oliver Wendell Holmes Jr said “Your rights end where someone else’s rights begin”. In this article, we’ll discuss the different sound levels of RC planes, what the law says about noise, and how to reduce your plane’s noise. Keep reading!
How Loud are RC Planes?
Electric RC planes are the quietest in the group of RC planes. In general, electric RC planes’ noise levels range from 40 to 60 dB when they’re measured from a 10 feet distance. This level of noise is comparable to the noise produced by a normal conversation. For me, this noise level is acceptable anywhere since it can go unobtrusive in an outdoor context.
For those of you who are not very familiar with RC planes and the concept of decibels, the sound level of electric RC planes is quite similar to that of drones (which is a type of RC helicopter 🙂 ).
I’m used to flying my HobbyZone Carbon Cub S 2 in my neighborhood, and honestly, I’ve never seen anybody complaining about it.
Nitro or gas-powered RC planes, tend to be much louder than electric ones. They generate a noise level ranging from 70 to 90 dB. It’s a broad range, but we can’t narrow it down because there is a big variety of models out there. This noise level is comparable to that of a lawn mower.
The louder noise of fuel-powered RC planes stems from their internal combustion engines, which run on fuel and oil and produce more power than electric motors.
You should keep in mind that a 10 dB increase is often heard as twice as loud by the human ear.
As it comes to RC jets, especially those powered by actual turbine engines, are the loudest in the RC community. Their noise level can easily reach 100 dB, it’s similar to a live rock concert. It’s loud enough that it requires the pilot to use hearing protection to prevent hearing damage.
My local club doesn’t allow RC jets unless it’s a special occasion, and focuses on choosing appropriate flying locations and times to minimize disturbance.
The relationship between dB level and perceived loudness demonstrates that as decibel levels increase, so does our perception of loudness. This is why electric RC planes, within the 40 to 60 dB range, sound relatively similar, while nitro RC planes present a more noticeable loudness difference between 70 and 90 dB.
What are The Legal Noise Levels Allowed?
In the United States, noise regulations for RC planes are generally guided by the AMA.
The AMA doesn’t set a strict legal limit for noise but provides guidelines to help you ensure that you don’t exceed the noise limits set by your local jurisdiction. On average, the noise allowed to cross the property line is between 50 and 65 dB (make sure to check your local laws). That means, if you are on your property, it doesn’t matter how loud is your RC plane as long as the noise doesn’t exceed the limits on the border of your property.
We should note that the sound level is reduced by 6 dB each time the distance from the source doubles. Here’s a table simplifying this principle.
| Distance (ft) | Sound Level (dB) |
| 20 | 80 |
| 40 | 74 |
| 80 | 68 |
| 160 | 62 |
Let’s say that your local jurisdiction sets the max noise level at 65 dB. To respect that limit legally, you can adjust either the sound level of your RC aircraft, or the farthest point you can reach in your property.
For example, I have an RC plane that makes a noise of 100 dB, another that makes 85dB, and a third that makes 55 dB. All these levels are measured from a 10 ft distance. Here’s a table explaining how far each airplane should stay from the border of my property.
| RC plane 1 | RC plane 2 | RC plane 3 | |||
| Distance (ft) | Sound Level (dB) | Distance (ft) | Sound Level (dB) | Distance (ft) | Sound Level (dB) |
| 5 | 106 | 5 | 91 | 5 | 61 |
| 10 | 100 | 10 | 85 | 10 | 55 |
| 20 | 94 | 20 | 79 | 20 | 49 |
| 40 | 88 | 40 | 73 | 40 | 43 |
| 80 | 82 | 80 | 67 | 80 | 37 |
| 160 | 76 | 160 | 61 | 160 | 31 |
| 320 | 70 | 320 | 55 | 320 | 25 |
| 640 | 64 | 640 | 49 | 640 | 19 |
That table shows that the first plane should fly at least 640 feet from the property line, the second one can go as far as 160 feet, but the third, even 5 feet from the property border is still in the legal range.
To measure the level of noise made by your RC plane you can use a dB meter, it’s available practically anywhere on the internet (Amazon for example) and it’s relatively cheap with prices starting at 20$.
You can find the full AMA guidelines here.
What Are The Factors Affecting the Sound Level?
We always notice the differences in noise levels between RC planes. We’ve already discussed the distinction between electric and fuel-powered engines, but what about the differences between two RC planes with the same power source? what affects it?
Engine Type and Size
There are multiple factors influencing the noise level of an RC plane, electric motors are generally quieter than internal combustion (IC) engines. Among the same power source’s engines, the size and the type of the engine affect the noise levels of the plane, for example, large two-stroke engines are louder than a four-stroke engine.
Propeller design
The propeller design has also an impact. The size, the shape, and the material used in the design of the propeller can influence sound production. The larger propellers move more air and can produce more noise, however, larger propellers can generate more thrust with lower RPMs which helps reduce the engine sound.
How to Reduce RC Planes Noise?
Select The Right Propeller
In general, the main source of noise in an RC plane is not the sound of the engine, but the one of the propeller. Three-blade propellers can reduce significantly the noise of your plane compared to the two-blade propellers. This reduction is due to the more efficient air replacement and the decreased need for high rotational speeds to achieve the same thrust.
Imagine you’re trying to lift something heavy, the heavy thing is your plane, and you’re the blade. If you’re two people you’ll need to make more effort to lift it, than if a third friend came in help. That’s the same thing that happens with the plane, the third blade is the friend who comes in help to reduce the effort made by the propeller to fly the plane.
Maintain Your Aircraft
Maintaining your aircraft is essential not only for reducing noise but also to keep it in good shape. Have you ever noticed those old cars that seem like they haven’t seen an inside of a garage for an eternity? Have you noticed how loud they are? The same thing goes for your RC plane.
Maintaining your RC plane improves the efficiency of the engine, keeps the mufflers in good shape, and keeps propellers running smoothly.
Install Mufflers and Use Sound-Dampening Materials
Mufflers are like silencers for IC engines. It helps control noise coming from the engine, which is multiple explosions happening very fast, catch it and let it out in a lower level.
Using sound-dampening materials has a similar effect to the muffler, you know how music studios or nightclubs are loud, but as soon as you step out of the door the sound becomes really low? It’s the same thing, those studios or clubs use sound-dampening material on their walls.