According to the Hearing Health Foundation, a dishwasher produces 75 dB of noise.
Interestingly, a recent announcement from Hartzell Propeller tells us that marrying the company’s Top Prop to a Diamond DA40 NG “delivers light, smooth and state-of-the-art improved climb performance, two to three KTAS faster cruise and is more durable, with an eco-friendly 74.1 dB(a) noise level.”
That makes the dishwasher louder than a Diamond.
We replaced our dishwasher a few years ago. If it’s running while we are sitting in the living room (15 feet away), it is barely noticeable.
For those people who aren’t enamored with aviation, it would be nice if a larger percentage of the aircraft we fly could be as quiet as a dishwasher — or quieter.
I’ll even hazard a guess that quieter aircraft would tamp down the pressure to close or restrict operations at the nation’s airports. It might even lower the heat on “getting the lead out” of avgas.
A July 10 story in The Wall Street Journal, “Private Aviation Struggles to Move Past Leaded Fuel,” has a few interesting nuggets.
“Now, growing opposition from airport neighbors on both coasts may help spur a broader transition away from leaded fuel that has been in a holding pattern for years.”
Growing opposition? Opposition to airports has been around for decades. Leaded fuel is simply a relatively new tool being used by anti-airport advocates.
The article quotes Greg Spades, a flight school manager at Reid-Hillview Airport in San Jose, who said the rule banning 100LL from Santa Clara County’s airports is “onerous and feels like deliberate interference by politicians.”
“They knew it would severely impact our business,” Spades told The Wall Street Journal.
Yep. That’s the point. Complaining about noise, for decades, has not produced the desired results. Time to change tactics.
Any time I’ve dug into noise complaint issues, the data shows a small number of people filing the vast majority of complaints. But that doesn’t make it any less of an issue.
The squeaky wheel gets the grease is a saying for a reason.
A July 11 story in Aviation International News, “Hawaii Governor Expected to Veto Helicopter Bill,” is more of the same.
Hawaii Senate Bill 3272 passed the state senate unanimously in April 2022.
From the bill: “The legislature finds that tour helicopters and small aircraft operations constitute a significant risk to passengers and residents on the ground. Over the past five years, tour helicopters and small aircraft operations in Hawaii accounted for nearly 17% of the nationwide accidents that prompted investigation by the National Transportation Safety Board. In one 10-month period spanning 2019 to 2020, 23 lives were lost in four separate tour helicopter or small aircraft accidents on Oahu and Kauai. Therefore, it is important that tour operators carry insurance in sufficient amounts to cover potential losses in the event of an accident. The legislature also finds that residents in the state must endure the excessive noise that helicopter tours generate.” [Emphasis added.]
Thankfully, as AIN’s headline reads, the governor is expected to veto the bill.
We can’t sit back and rest on the “airports were here first” retort. Well, we can, but that’s a bad idea, in my opinion.
If I happened to be the first person to move into a new community, I don’t automatically get my way just by being first. And yet, I often read, “the airport was there first, the complainer can go pound sand,” often given to someone who complains about aircraft noise.
I no longer wonder if it is possible to make aircraft quieter. The Hartzell announcement tells me so.
Now, I’m not a mechanic. Nor am I an engineer. But it seems to me the three biggest contributors to internal combustion engine aircraft noise, in no particular order, are the engine, the muffler, and the propeller.
I do know that everything in aviation is a trade-off. I expect people who know such things will tell me that producing a muffler that actually muffles the sounds of the engine will result in reduced performance in some manner. And to reduce the sound from a propeller, the performance of the aircraft will suffer. And if you want a quieter engine, that means a smaller engine, and that means…you guessed it, reduced performance.
And yet, I still want our aircraft to be quieter.
So, if it’ll help the engineers make aircraft quieter, it’s okay if they can’t also do dishes.
I have just read the first sentence of this article and am already compelled to respond. I will read the entirity, and then add to this comment,
The statment “.. a dishwasher produces 75 dB of noise” is completely nonsensical.
A decibel is an expression of a power ratio. It is not a unit of measure. There is dBm (ratio relative to a milliwatt), dBv (relative to volt at some impedance), and dB SPL.
SPL stands for sound pressure level. Sound pressure is measured in units of Pascal (PA) . The accepted reference level for SPL is 20 uPa. 20 uPa is near the threshold of what humans can hear, so an arogant person might think that is “zero”. But no, it is just a reference level for a ratio.
The point is! “dB” means NOTHING without a reference.
We should work on ways to make our airplanes quieter, both inside and out.
The easy way for inside noise is a pair on ANR headsets. A better way might be sound deadening material here and there, some of it is very light and can be friction fitted into spaces between bulkheads. It doesn’t affect weight and balance, and since it is not permanently attached, no STC is needed. There is also sound deadening paint which can be applied to the backs of the various inspection ports in floor of the cabin. There are plenty of large unsupported interior trim panels (aluminum and plastic) which “drum” and vibrate, adding to the interior noise. Some Cessna doors have a large air space in the lower half between the door skin and the interior trim panel. This is a good location for sound deadening material. If you are changing the windows in your airplane, see if you can get thicker windows, sometimes they are available but might be tricky to fit. Spruce has a little pamphlet about noise control in light aircraft – they give it away for free.
Outside the aircraft, there’s not much we can do. Many light aircraft “mufflers” are really only spark arrestors and don’t quiet the exhaust much. As was mentioned, in Euroland there are much more stringent noise regulations, and I have seen systems that look like a long pipe with a muffler hanging off the bottom of experimental and light sport aircraft. Beyond that, we are limited to flight paths that avoid the most populated areas, and flight times that are not very early in the AM or late at night.
The cure for this is when we (eventually) start flying electric airplanes. That won’t be any time soon. In the meantime, we can hope that someone will develop STCs for quieter exhaust systems for GA aircraft. We can’t do much about airframe noise, that’s a function of the design of the aircraft, but fortunately, that isn’t a major issue for most GA aircraft, much more so for the big iron.
When a community stops the noise of their teenage kids playing rap at 100 Db from their economy class rice rockets with glasspac mufflers on them, I will worry how my one flight a month is too noisy for the local community!
Noise comes from many sources… Including the airframe… which can be very pronounced.
Cooling airflow thru the cowling, un-faired tires/struts, poorly sealed joints or panels, etc can cause noise… and noise often changes with airspeed and flaps settings.
The USAF T-1 Jayhawk is an annoying ‘whistler/howler’ in the pattern. I’ve been around a long time in aviation and I can ‘spot/ID’ many aircraft types by their distinctive sounds. So can You IF You are listening for them.
Occasionally I hear a unique aircraft sound that draws me away from my work to the search the skies. Piaggio Avantis, T-28s, Stearmans, B-29 [Doc], homebuilts, certain helicopters [CH-47s, HH-60s, V-22s, etc], etc.
NOTE. IF You pay close attention, all-electric Tesla-cars rolling at more than just parking-lot speeds, have distinctive automobile noises due to tire rolling, suspension and aerodynamics… making them almost indistinguishable from similar sized piston-engine economy cars.
“the three biggest contributors to internal combustion engine aircraft noise, in no particular order, are the engine, the muffler, and the propeller.”
The muffler does not “contribute” to the noise, it muffles the noise from the engine exhaust. Judging by how quite automobiles are, I believe that a properly designed exhaust system could reduce noise quite a lot with out affecting the power output that much. I suspect it is the weight penalty that causes aircraft designers to just slap the smallest, lightest system on and say that it is the best that they can do. The Europeans have much more strict noise regulations, and have found ways to comply.
Unfortunately, the JetPod initiative seems to have died with the death of its owner, Michael Dacre, during a test flight. If I remember correctly, it used active noise cancelation to reduce the noise levels generated by the jet taxi.
Of course, the complaining homeowners
don’t hear the aircraft while their lawnmowers, weed eaters, leaf blowers and grass edgers are creating more noise than two light airplanes.
Maybe it would be as simple as organizing airport denizens to write letters as well. Become a “squeakier wheel”, as it were.
Odd how people buy land next to an existing airport, build a house, move in, then whine about noise! Would they move in next to a pig farm and bitch about the stink?
They do complain about the pig farm.
Yes. Pig farm in Kirkland WA that exact thing happened
That noise figure is outdated. The newer dishwashers produce around 35-48db of noise, so your new dishwasher is likely at least 8 times quieter than 75 db (noise halves with every 3db reduction). 75db is still pretty quiet as aircraft go though, so the achievement is still laudable.
Thanks for the update Bob.
8 times? Uh, no. The higher level of 48 dB SPL is 27 dB lower than 75 dB SPL. That is about 500 times the power of the sound from a dishwasher. Sound in air to our ear is analogous to voltage, and from that perspective, 27 dB is about 22,000 times the volume.
So the difference is a whisper compared to a vacuum cleaner.