Students invent quieter leaf blower
hub.jhu.eduMinor nitpick about the reporting:
> The team reduced the overall leaf blower noise by about two decibels, making the machine sound 37% quieter.
While a 2 dB reduction in noise does represent a 37% reduction in acoustic power, our perception of sound is logarithmic so this is extremely unlikely to "sound 37% quieter"-- Assuming the reduction is from 50 dB to 48 dB, it will sound about 4% quieter.
Much more significant is the 12 dB reduction in the "shrill and annoying" frequency range. While the 94% reduction there is probably also overstated for the same reason, the initial power level in that range will be only a portion of the overall noise output-- I wouldn't be surprised if there's a 50-75% perceived reduction of noise in this range.
In the video, we see the students briefly rotating the model in the CAD software—with translucency on—it looks like the one main stream is divided into many spiral chambers which then exit distributed along the rim of the attachment's opposite side.
With that in mind, I wonder how much, if at all, the reduction would be if the entire nozzle were designed this way, instead of just the end bit.
They probably should look at this for server cooling as well. At 2u or smaller those things are leaf blower loud, and there’s a lot of depth in those cases that could be sacrificed for decibels.
> Much more significant is the 12 dB reduction in the "shrill and annoying" frequency range.
Those higher frequencies travel farther than the lower frequencies, so cutting them has a bigger perceived effect (and this is all about perceived effect, I believe, not the health effects of the operator).
Just agreeing with you that acoustics is complicated and non unidimensional.
60db is normal conversation/background music level. I don't know why you'd assume a leaf blower would start at 50db?
After reading all comments, not rushing to the comments, I have to say, I have a quiet leaf blower to, it is, as mentioned in this thread somewhere else, a rake and I would appreciate if more people would use one.
>a rake and I would appreciate if more people would use one.
Most of the leaf blower noise in neighborhoods is cleaning up tiny grass clippings off of driveways and sidewalks instead of handling the Fall season's dead leaves, like this: https://www.youtube.com/watch?v=ak5VoB-ceeU&t=0m06s
Rakes don't help with grass cuttings. People could use brooms to sweep up the grass but homeowners and lawn crews don't do it that way because -- like the rake -- it requires more work and takes a lot longer than using noisy blowers.
Another option is a hose, but that may be considered more wasteful.
I have a leaf blower, and I use it for about 5 minutes a week in the summer to clear grass clippings from walkways after I mow. I don't like being "that guy", so I pretty much run around the yard with it in order to finish as quickly as possible.
I know that the electric leaf blowers are quieter, but my neighbor's makes a high pitched squeal which bothers me more. I think that she has some sort of condition, because she's literally using the thing for about three hours a day. I don't know how many battery packs she has, but she runs it until it dies, swaps the pack, and gets back to it. It's not a huge yard, maybe 1/3 of an acre, but she is compelled to get every blade of grass off of her driveway.
There's a guy in my neighborhood (who uses a backpack blower) and this is his main hobby. I really don't understand the appeal of doing what is a pretty monotonous task for such a long amount of time, given that in mere hours much of the pristine front yard moves back into "chaos".
I understand the satisfaction from being meticulous about things like this, but i don't understand the extreme end of it.
Most of the leaf blower noise in my neighborhood is the one or two guys on the crew who's job it is to run the leaf blower while the other guys are doing the lawn mowing or edging.
If it was that guy's job to use a rake and broom instead of a leaf blower, the same amount of cleaning would be done.
Try doing that 12 hours a day 5-6 days a week for 1 year and report back your findings to us.
Hear hear. Rakes can be more efficient[0], provide an upper-body workout, minimise impact to the environment, make next to no sound, cost almost nothing, and provide a relaxing experience if you know how to embrace it.
I suppose these days people take techno-efficiency over all else to the point of ruining the environment, other people's peace, their own air quality, their own wallet, and so on, all so that they can blow the leaves off of their lawn in a supposedly shorter time or for slightly less effort.
Slightly less effort? Have you used a leaf blower before? It’s a 30 minute to 3 minute sort of difference.
This video is way too funny. Thank you for sharing.
Extremely large rakes and brooms exist that can be used to clear areas efficiently with proper technique. In the past, I had to tend to a ¾ acre property with pine trees and at least a ½ acre of lawn.
Why rake at all? Mulch them instead. Raking them into a bag to have removed from your property to add to a landfill just seems like a very strange decision to me.
Raking them into a pile, shredding them, and putting the mulch in a compost pile allows me to move the nitrogen into my garden. Maybe that starves part of my lawn, but the grass seems to be doing just fine - and moving natural nutrients to my garden helps me avoid using chemical fertilizers when growing food.
I am agreeing with you, for the record. It seems silly to throw leaves in a landfill.
I do a combination of both. I have a compost pile that is fed by collecting the clippings from my mulching mower from half of my mow-able area, and then the rest is just mulched and left in place. Essentially, anything to not rake! The only time I rake/bag is from the leaves that collect along the curb. I'm on a cul-de-sac, so I get a lot collecting there. I don't use these for compost from all of the liquids from parked cars, trash, and other gross stuff that I wouldn't want in my garden.
Depends on the state of the property. On a low water and au naturel yard, sure. Manicured lawns and sterility are all about anthropocentrism while expending concealed absurd treasure and effort without much concern for the soil losing nutrients. Or it's the middle class still clinging onto disappearing symbols American dream of how "rich" they are like the French aristocracy once did. You should've seen how deep green with a tint of blue my dad's 30' x 40' front lawn of Bolero dwarf fescue was, which required mowing twice a week in the summer by you know who, tens of thousands of gallons of water, and regular fertilizing.
I mulch, but it's slower and requires more frequent mowing. The first mowing of the year (I always wait too long) is nearly impossible with a push mower mulching.
It's mentioned in the article but easy to miss, this is an improvement on the already much much quieter electric leaf blowers that are readily available. The ones you are thinking of are two stroke gas powered ones which are loud as fuck and terrible for the environment, anyone using one of those could have gotten a quieter electric one but chose not to, which means they definitely aren't going to use this improved electric one.
> they definitely aren't going to use this improved electric one.
The (major) manufacturer they demonstrated it to seems to have adopted it.
Maybe they'll expand the concept out over time to the two stroke ones as well. :)
Yeah except the electric ones that I've used kinda suck. I have an electric leaf blower from Ego and a gas backpack one. The electric one is awesome for blowing the grass off the driveway after mowing or other light tasks. OTOH I used it to manage the leaves in our quarter acre or so backyard last year, and it took me three charge cycles using two batteries each every time I tried to move the leaves. I ended up just raking both years. Last year I finally bought a backpack blower after trying one out with a friend on a much smaller property. It blows harder and has the endurance to actually finish the job.
You are right, and I agree with the last bit for the record.
But, keep in mind that "just going electric" isn't a good option universally. It's MUCH more expensive to put together an electric setup and the number of batteries necessary to do any significant amount of work than it is to buy even a mid range backpack 2-stroke blower. Especially if you do what a lot of people do and look for used equipment to save a ton of $.
If you have a small yard or are only ever doing stuff like blowing off a deck/patio/sidewalk/driveway: battery 100%. if you need to do any significant amount of leaf management in a larger area: good luck.
I have an m18 electric, and gas Echo backpack. If im cleaning off a sidewalk/patio, cleaning gutters, etc.. im 100% using the electric. Otherwise....not so much. I don't even clean up grass clippings, mulch and cut frequently enough that they aren't an issue.
I use a corded electric blower (it's also the motor for a shop vac). It works very well for the driveway, blowing out the garage and, for the very rare times I've done it, leaves on grass.
corded ones can be great. I moved to a battery powered one for cleaning gutters because eventually the cord was going to trip me on the roof and cause a fall.
obviously less convenient than gas or battery, but they can be good for stuff reasonably close to your house.
A few years back Moxie (of Signal) put up a video[0] of a quiet leaf blower which was pretty sweet. His design appears to be quieter than this one. Either way this is great, as a person highly sensitive of sound I support all technologies that reduce excessive noise.
I can't help but notice in that video that it's really not moving the leaves too much, and that's on the most ideal surface you could have.
That's a good observation. Making a quieter leaf blower by greatly reducing its output is pretty easy. But the professional landscaping crews getting paid by the hour won't choose a tool that makes their job take 5x as long.
Random thought: Would it be beneficial if residentially-annoying equipment was required to fall into certain standard frequency/harmonic pprofiles? Would that make it easier and cheaper to design absorptive or anti-noise measures?
In other words, a world where you could buy super-cheap earbuds guaranteed to nullify all leaf blowers.
Figure out what ranges of sound are attenuated well by foliage, siding, wall insulation, gypsum board. Though it’s probably windows most of the sound comes through so what frequencies are lowered by double pane windows.
Hmm. They claimed they didn’t reduce the thrust. Maybe the vortex is screwing the blowing-ness or they are measuring it wrong.
This is great. I live in a dense suburb and the weekend is just a cacophony of deafening noise from leafblowers, table saws, pressure washers, lawn mowers, etc. My neighbor had a team of people grinding and cutting stone slabs for their patio from 9-5 last weekend. Wish people would chill out.
As a side note, leafblowers aren't just disruptive to the sound environment: https://twitter.com/touchmoonflower/status/17242321111447757...
I haven't put any leaves out on my curb the last two years, but I still use my electric leaf blower. Early in the season, I use my mower to mulch some of the first leaves to fall into the lawn(which consists of grass, clover, violets, dandelions, etc). But eventually there are just too many leaves to mulch, and they would smother everything, so I blow them into big piles. Then we take the dogs out to play in the piles. Then we scoop them up with tarps and spread them all over my veggie garden beds. In fact I went and "stole" some leaves from the piles my neighbors put on the curb to get even more coverage of my gardens. Now in spring, the leaves have smothered a lot of weeds, and the ones that do grow are easier to pull because they have to push through the leaves and the dirt stays moist longer. I see a lot of insect life living in the leaves as I go about weeding. I hope the ecosystem is strong to balance out pests on my veggies.
Is leaf blowing a worldwide nuisance or an American thing?
I hate it. And it serves no ecological purpose.
> And it serves no ecological purpose.
At least from my experience, it's not done for ecological purposes. It's primarialy done to clear pathways for safety, maintenance, and aesthetics.
Some people do blow a whole lawn, but that never struck me as useful. Cleaning up the path is nice though, and depending on your paths, makes plenty of noise already.
Safety on paths makes sense, but in many neighborhoods, that’s doable with a rake in a few minutes vs an hour to do the lawn with a blower.
My neighborhood has a landscape crew do the leaves in the common areas 3x season. If we just had them do the paths and parking lot, it would be half the time (or less) with blowers.
Worldwide.
Sucks to be an earthling trapped here with leaf blower jerks.
France. I know my city workers use them to clean the streets in autumn. Wet leaves are slipery. Then people mostly use rakes AFAIK, or the lawn mower.
Though I know some tools, such as branch shredders are regulated in some residential areas, but I don't frequent those.
I blow the leaves off my gravel driveway that winds through woodland. I got 2 Ryobi electric leaf blowers free with different cordless tools and so I dual wield them as I walk down the driveway a few times every fall.
I don't care about leaves on the lawn.
This is perhaps the most practically useful thing to come out of academia since the technology that allowed for the leaf blower.
They're the worst. A noise pollution posterchild.
First, it's an attachment that could fit on nearly all blowers.
Second, it dampens the noise while retaining all the force.
If this works out, it will be amazing! Kudos to the student teams!
Looking forward to being put on a list for purchasing a leaf blower silencer.
Not to mention the 3D print files.
Dupe from yesterday: https://news.ycombinator.com/item?id=40377201 (400+ comments)
About 10 years ago, I remember seeing someone using an electric leaf blower connected by extension cord to a Honda generator strapped down to a furniture dolly to circumvent the gas-powered leaf blower ban. It was still pretty damn loud and annoying, but less than the oft muffler-less, 2-stroke modified leaf blowers most gardening crews use unconcerned with emissions or noise pollution.
I really hate leaf blowers. They are the main generator of noise in our neighborhood and they don’t conserve that much energy in most cases than a rake (and in some cases are less efficient). I’d be happy if they were banned in residential neighborhoods. Edit: not the mention the pollution from the gas powered ones which most are.
Congrats to these students for producing a clever solution to a real practical problem! I hope that the students will own the patent, and not the university. Many schools have a way of taking ownership of absolutely anything their students come up with.
That said, I prefer just raking up leaves manually. It makes no noise, it's quiet, and it's good exercise.
I agree completely! My favorite weed killer is my own two hands and a weeder. Having said that, I live in Arizona and the dominant landscape design here is trees and bushes planted with rocks for the ground cover. A leaf rake is real good at picking up both the leaves and the rocks. I wish there was a leaf rake that didn't pick up the rocks. I have grudgingly bought an electric leaf blower because of the rocks :-(
> That said, I prefer just raking up leaves manually. It makes no noise, it's quiet, and it's good exercise.
I think a lot of folks in these discussions think only of lawns. That's a pretty small portion of where leaf blowers get used, in my experience. The lawn mower takes care of most of the leaves on the lawn, the blower gets used around bushes and other places a rake won't work at all.
Patented and licensed, so not coming to a neighborhood near you unless mandated by local government. Because while people want their neighbors to use it, in enough cases they won't pay the extra and rationalize it somehow.
HOAs that hire landscapers are a good market segment for this imo. Also, large commercial properties.
You wouldn't download a quieter leaf-blower...
unless of course you had a 3D printer
ATF: you got a tax stamp for that suppressor?
One thing i never understood: Why a blower instead of a vacuum type of device...?
Speed, mostly. There are blowers that also act as vacuums. It works okay, but still pretty slow, if you blow it all into a pile first. You could do better with a wide device that worked like a lawn mower, but that would only be useful for a fraction of the areas you are trying to clean up.
they exist, I have a one that works both ways, it can blow leaves and it can suck in and mulch the leaves into a bag. Some reasons you don't see it as much include
1. mine jams extremely easily when sticks or wet leaves get into it 2. their ability to actually move leaves is significantly less when in suck mode vs blow mode, this is not specific to moving leaves, try sucking sugar throw a straw vs blowing it, blowing moves stuff MUCH more.
Direct link to noise comparison in the video https://www.youtube.com/watch?v=ISgHpUDeLBw&t=64s
How does it compare to the ultra quiet electric leaf blower that was on HN 7 months ago?
If I had the financial resources, I would buy every yard service company that serves my immediate neighborhood, specifically those that love to do their work at 7 AM on Saturdays.
Only one minor thing wrong; it's still a leaf blower.
I didn't know of electric-battery-powered leaf blowers! Here in France i always suffer gas engine blowers which are so annoyingly loud and smelly.
The problem with electric leaf blowers is that they're no good for people who need to blow leaves all day; and most of the leaf blowing is (in my experience) contracted out rather than done by home owners.
I have an electric blower that I use for getting leaves off my decks (you can't rake a deck and it's actually a remarkable pain in the ass to brush leaves off a deck) but if I got a contractor in to do my garden (which I don't, they just get mowed over) then they would certainly have a gas blower.
Dewalt has battery packs that are quickly interchangeable and pods with rows of batteries that can be recharged inside a car or truck while on the go. I'm hoping this becomes adopted more and more as the tech is already here.
Proprietary batteries with a format that changes subtly from model to model are not the answer.
I'm in Australia and someone near me has an electric one.
Although quieter than the gas ones, it's still far from silent and the noise is still annoying but higher pitch. Like a high-pitched vacuum cleaner noise.
Most people have the much louder gas ones though, they're the worst, and anecdotally the people operating the gas ones seem to rev them up and down more which makes it even more annoying.
Every time I hear one, I have nothing but negative thoughts about the person using them, and disgust for the society that allows them to ruin the environment for such minimal benefit.
A rake works almost silently... but then you can't irritate everyone within a kilometer radius.
Can someone explain why it's going to take 2 years to bring a piece of plastic to the market?
I watched the demo video, and, IMHO, even the muffled version of the leaf blower is way too loud.
Leaf blowers are probably one of the most annoying inventions ever.
So shitty neighbors can be slightly less loud. :)
Can we apply this to vacuum cleaners too?
Honestly I expect to see a Dyson Leaf Blower.