PROP Noise

ksandrew

ksandrew

Pre-takeoff checklist
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Oct 22, 2014
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118
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1GA6 Dawson Georgia USA
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ksandrew
Hi.

Trying to be a good neighbor and especially during deer season I am trying to make my morning departure from a private strip as quiet as possible.

I recorded a visitor departing in the same plane that I have and was surprised by the prop noise. He was at gross weight.

I seem to remember being told that when the prop blade tips exceed the speed of sound that the noise is greatly increased.

I have not put pencil to paper yet to determine my blade tip speed.

Any thoughts?


Ken Andrew
trying to attach a video
If vid does not work try https://www.youtube.com/watch?v=pL_IelhfJrQ&feature=em-upload_owner
 

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Some folks have clipped a wooden clothes pin onto the shaft of their prop control, personally I'd rather have full power and make a little noise.
 
Fly off of a frozen creek at 6' ASL in -35* and turning the prop down is required. No matter, the engine is making more power and the wings are making more lift at those temps so performance is still off the scale.

Retracted AirGlide wheel skis give the pilot a full dose of his own prop noise!
 
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James331 said:
Worse?

That's what a airplane is sposed to sound like :D
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Couldn't agree more....love a 185 launching!!!:yes:

Way better than anything Beethoven ever composed.
 
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So you're looking to turn rrrrrrrrrrrraaaaaaaaAAAAAAAAAARRRRRRRRRRRRGGGGGGGGHHHHHHHHHHH into rrrrrraaaaaaaaaAAAAAARRRRRRRRGGGGGGHHHHHHHHH, eh?


...it's an airport. There's gonna be noise.
 
Captain said:
So you're looking to turn rrrrrrrrrrrraaaaaaaaAAAAAAAAAARRRRRRRRRRRRGGGGGGGGHHHHHHHHHHH into rrrrrraaaaaaaaaAAAAAARRRRRRRRGGGGGGHHHHHHHHH, eh?


...it's an airport. There's gonna be noise.
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You are out of touch......there is what's called whisper mode......I have seen it in action. Watch the movie Blue Thunder....it came out in 1983 so I'm sure there is better technology now!!:D:
 
That's not specially noisy, have you listened to an A-36 takeoff from pavement at the same distance you were for this? Grass is quieter than pavement. If you want to minimize your noise impact, stand on the brakes while pushing the throttle in, then follow with a Vx climb to 500' and transition to Vy.

If you're at a private field, make a left 180 when clear, so that your noise is over the area you disturbed with your taxi and takeoff roll instead of extending out over more land.
 
Let'sgoflying! said:
The FAA has actually acquired some dB measurements on some of our a/c
https://www.faa.gov/about/office_or...t_noise_levels/media/APPENDIX_02_20120405.xls
It looks like yours is pretty low (or is that a 114?)
also
https://www.faa.gov/about/office_or...aft_noise_levels/media/uscert_appendix_07.xls
https://www.faa.gov/about/office_or..._levels/media/uscert_appendix_08_20120424.xls
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Agree from the video didn't see too outa whack to be concerned about.

Planes make noise.....some louder than others....whatcha gonna do...stay on the ground and polish your props??

**** people off....that's what we are privileged to do.....if you don't like it....get your PPL AND JOIN THE CROWD!!!! :yes:
 
ksandrew said:
Hi.

Trying to be a good neighbor and especially during deer season I am trying to make my morning departure from a private strip as quiet as possible.

I recorded a visitor departing in the same plane that I have and was surprised by the prop noise. He was at gross weight.

I seem to remember being told that when the prop blade tips exceed the speed of sound that the noise is greatly increased.

I have not put pencil to paper yet to determine my blade tip speed.

Any thoughts?


Ken Andrew
trying to attach a video
If vid does not work try https://www.youtube.com/watch?v=pL_IelhfJrQ&feature=em-upload_owner
Click to expand...

If runway length isn't an issue, you can not use the last couple hundred RPM for take off at noise critical times. It doesn't take much to get it to quiet down. What you want is prop tip speed of <.92M for efficiency as well as noise (the noise is the result of a high drag event)
 
Henning said:
If runway length isn't an issue, you can not use the last couple hundred RPM for take off at noise critical times. It doesn't take much to get it to quiet down. What you want is prop tip speed of <.92M for efficiency as well as noise (the noise is the result of a high drag event)
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He's not at Montgomery field where they hate everything from weed cutters to weed blowers....let alone a flipping aircraft taking off. Plus field looks to be in B eff E.

From the video....it doesn't seem excessive....there are much worse out there.

Not sure much u can do for noise abatement with what the OP has. Sure can lower that a bit....but not within safety person limits IMO.
 
You guys with your 88" props remind me of the rednecks in H.S. that would bust the glass out of their glasspack twice pipes.

All show and no go.

:stirpot:
 
txflyer said:
You guys with your 88" props remind me of the rednecks in H.S. that would bust the glass out of their glasspack twice pipes.

All show and no go.

:stirpot:
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Don't hate on the TW drivers!!!;)

We would show it to you....maybe....if you have a TW.:D

Doesn't apply to your beautiful bird!!!:lol:
 
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James331 said:
Some folks have clipped a wooden clothes pin onto the shaft of their prop control, personally I'd rather have full power and make a little noise.
Click to expand...

Well, except that as the prop tips approach the speed of sound you lose efficiency and power.

Thus

More Noise = Less Power in many cases.

txflyer said:
All show and no go.
Click to expand...

Exactly.
 
I don't know how to calculate loss of efficiency vs increased power but I've had my prop spinning too fast and found the performance was excellent. Prop speed would calculate to about .96 Mach on an average summer day. Was it better enough to **** the world off with all the noise? No. Even airplane nuts covered their ears when I took off. I try to maintain about .9 Mach for best performance and tolerable noise. In town I'll turn the prop down to 2500 before I'm over the departure end to mitigate noise and that's on a 2100' strip. No reason to shake up the neighbors when I'm at a couple hundred feet and climbing nicely.

Seaplanes and STOL ops clearly favor long props. There's no dispute about that. My prop is 86" and it pulls harder than anything else in testing. To use a shorter prop is giving up out of the hole acceleration, climb rate, and braking. Pick your prop based on your priorities.
 
Deer in that area most likely care less about the plane. When I'm on my tractor I can drive right down the lane with deer to the side they look up and watch me pass. When I'm in my camo trying to sneak to my stand they bolt before I get within a hundred yards hahaha
 
timwinters said:
Well, except that as the prop tips approach the speed of sound you lose efficiency and power.

Thus

More Noise = Less Power in many cases.



Exactly.
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Right, all the extra performance is turned into drag and noise.
 
MotoFlier said:
Deer in that area most likely care less about the plane. When I'm on my tractor I can drive right down the lane with deer to the side they look up and watch me pass. When I'm in my camo trying to sneak to my stand they bolt before I get within a hundred yards hahaha
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That's because animals perceive your thoughts. Airport deer sure don't scare easy. One place I used to stop with a grass strip sometimes you'd buzz em 2-3 times as they meander around not too impressed.
 
timwinters said:
Well, except that as the prop tips approach the speed of sound you lose efficiency and power.

Thus

More Noise = Less Power in many cases.



Exactly.
Click to expand...


You don't understand aerodynamics.

The sound of a 185 prop going supersonic scares the ground, thus propelling the aircraft off of it faster.
 
James331 said:
You don't understand aerodynamics.

The sound of a 185 prop going supersonic scares the ground, thus propelling the aircraft off of it faster.
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There are times I wonder if there is a shockwave value to a 185's STOL performance component, it sure is a bunch of energy bouncing off the bottom of the wings....
 
Keep density altitude in mind for prop settings. At my cabin a winter takeoff may have a density altitude of -6000'. Your engine power may need to be adjusted down to compensate but full throttle fuel flows are critical to supply enough fuel (cold air makes lean mixtures). Things to consider for cold weather flying.
 
*****************TOGW* MLW ******************TO APP
MANUFACTURER AIRPLANE ENGINE 1000 LBS 1000 LBS dBA dBA
CONCORDE CONCORDE O-593/M-602 400. 112.9 109.5

BEECH C35 E-185-11 2.7 2.7 75.
BEECH E35 E-225-8 2.7 2.7 75.
CESSNA 180 O-470-J 2.8 2.8 69.


Concorde wins hands down. However, the top two piston planes are old Bo's like I drive. I take off at full power, and pull it back to 2200 as soon as safe. I calced the tip speed once on my 88" prop. It was close enough to trans-sonic to make some serious noise. Cessna 180, well - honorable mention but no podium.
 
redline on a stock 180 is 2600 with up to 88" prop. A 185 is 2850 w/ 86" prop. Which is noisier is easier to figure out.
 
Stewartb said:
redline on a stock 180 is 2600 with up to 88" prop. A 185 is 2850 w/ 86" prop. Which is noisier is easier to figure out.
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Survey says: 180 is louder;

CESSNA 185F I0-520-D 3.4 3.4 66.
 
C'mon up to Lake Hood and watch floatplanes take off for a few minutes. You'll figure it out for yourself. Beavers can be pretty loud, too, but there's no question the IO520 185s are louder than 180s. I can't imagine anyone who's been around them would have any doubt!
 
I didn't take the readings, I don't own the instruments, I am just the presenter. Take it up with the Fedguv if you disagree.
 
Don't need to. Anyone who's heard both knows the answer. That's good enough for me.

Some EX Cub guys are spinning 92" props at 2700 with nitrous. Those things can make some serious noise, too!
 
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MotoFlier said:
Deer in that area most likely care less about the plane. When I'm on my tractor I can drive right down the lane with deer to the side they look up and watch me pass. When I'm in my camo trying to sneak to my stand they bolt before I get within a hundred yards hahaha
Click to expand...

Henning said:
That's because animals perceive your thoughts. Airport deer sure don't scare easy. One place I used to stop with a grass strip sometimes you'd buzz em 2-3 times as they meander around not too impressed.
Click to expand...

You should see the ones in our neighborhood. They barely look up from eating my wife's flowers. Forest rats!
 
James331 said:
Worse?

That's what a airplane is sposed to sound like :D
Click to expand...

TEFLONSEAN said:
Couldn't agree more....love a 185 launching!!!:yes:

Way better than anything Beethoven ever composed.
Click to expand...

Please reference the "Sedona Needs Our Help" thread.

95% of the U.S. population don't share the love for airplane noise and the above attitude leads to airports like Sedona needing our help.

just sayin'.......

I love hearing an airplane but I fully understand that most people don't.
 
Stewartb said:
C'mon up to Lake Hood and watch floatplanes take off for a few minutes. You'll figure it out for yourself. Beavers can be pretty loud, too, but there's no question the IO520 185s are louder than 180s. I can't imagine anyone who's been around them would have any doubt!
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Are we talking the two bladed or three bladed?

I'd wager a 2 blade 180 is louder than my 3 blade 185

Heck some SPBs require a 3 blade prop.

image.jpg





timwinters said:
Please reference the "Sedona Needs Our Help" thread.

95% of the U.S. population don't share the love for airplane noise and the above attitude leads to airports like Sedona needing our help.

just sayin'.......

I love hearing an airplane but I fully understand that most people don't.
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Then don't live by a frickin' airport.

Sadly we've devolved into society of idiots who can't figure that one out and don't have a set big enough to tell these people to kick rocks.
 
James331 said:
Then don't live by a frickin' airport.

Sadly we've devolved into society of idiots who can't figure that one out and don't have a set big enough to tell these people to kick rocks.
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Except it's not just about airports.

I've been on rafting trips (in a wilderness area) and some idiot comes down the river at 200' AGL with the prop full forward.

I've been sitting in Geyser Basin and watched a 182 circle for 10 minutes at about 500' AGL waiting for Old Faithful to blow.

I've been backpacking (again in wilderness areas) and had planes pass over me quite low...again far lower than the requested 2,000' AGL.

I've been on lakes (Tablerock, Lake of the Ozarks) and had planes buzz directly over our boat as low as 50'.

If it was just airports, then we might have a defense. But it's not. Arrogant a**hole, inconsiderate pilots are everywhere and people justifiably hate us for it.
 
Two or Three blade doesn't make much difference on a Cessna 185.

It is the length that counts. The McCauley "401" 86" 3 blade prop is obnoxiously loud.

I bought one and always wished I hadn't.
 
timwinters said:
Except it's not just about airports.

I've been on rafting trips (in a wilderness area) and some idiot comes down the river at 200' AGL with the prop full forward.

I've been sitting in Geyser Basin and watched a 182 circle for 10 minutes at about 500' AGL waiting for Old Faithful to blow.

I've been backpacking (again in wilderness areas) and had planes pass over me quite low...again far lower than the requested 2,000' AGL.

I've been on lakes (Tablerock, Lake of the Ozarks) and had planes buzz directly over our boat as low as 50'.

If it was just airports, then we might have a defense. But it's not. Arrogant a**hole, inconsiderate pilots are everywhere and people justifiably hate us for it.
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None of that sounds all that bad :dunno:

Not as annoying as someone having a FaceTime chat on their phone at a bar, yet we don't try to shut down all the cell towers or apple stores

Not as annoying as screaming children at dinner, yet you don't see "no children" signs at steak joints.

I could go own.



kgruber said:
Two or Three blade doesn't make much difference on a Cessna 185.

It is the length that counts. The McCauley "401" 86" 3 blade prop is obnoxiously loud.

I bought one and always wished I hadn't.
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The stock 3 blade is 6" shorter than the stock 2 blade.

image.jpg
 
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James331 said:
Not as annoying as screaming children at dinner, yet you don't see "no children" signs at steak joints.
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Boy, now there's one we agree on.

As long as I can remember, when asked by the hostess at a restaurant "smoking or non?" I'd respond with "do you have a no kids section?"

"No" was the standard answer.

"Well, you should have" was always my retort.

Long after I quit smoking, I'd still sit in the smoking section when travelling solo (if it wasn't too smoky). I'd far rather breathe a little smoke than put up with a screaming rug rat.

But...

If you don't see the issue with people flying at treetop level over a wilderness area...I think we've found our problem...
 
James331 said:
None of that sounds all that bad :dunno:

Not as annoying as someone having a FaceTime chat on their phone at a bar, yet we don't try to shut down all the cell towers or apple stores

Not as annoying as screaming children at dinner, yet you don't see "no children" signs at steak joints.

I could go own.
Click to expand...

So FAR 91.119(c) doesn't matter? Is there a FAR against screaming kids in restaurants?

I don't like spoiled kids either, but we as aviators are in trouble if the public decides to rise up and ground us because we don't care about those on the ground.

Our sin is not justified by someone else's sin.
 
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