Get Rid of the Noise

[Piloto]

If Mooney Aircraft wants to get an edge over the competition it should consider making the new models quieter for those onboard. Can you imagine the "wows" comments when you can talk to your passengers in the same way you do in a car with no headsets. Would you buy a car that requires headsets to talk to the passengers? Or fly on a noisy airliner that requires earplugs? 

 

The noise issue has been ignored because aviation enthusiast are used to headsets. But it can be a decision maker when buying a $700k plane. To many potential buyers a quieter plane is more desirable than one that is a few knots faster. After all you are not buying a $700k plane for racing but to go places in a comfortable way.

 

Cabin noise reduction has been an important issue in the automotive industry and the jetliners, shown to appeal to customers. The technology is already there. Be the first. 6dBs quieter than the SR-22 will appeal more than 6kts faster.  

 

José  

[Bob_Belville]

 6dBs quieter than the SR-22 will appeal more than 6kts faster.  

 

José  

Nonsense. 

[Mooneymite]

The solution is more speed.

The cockpit is very quiet once you exceed mach.

[HopePilot]

With headsets constantly improving, I have opted against additional noise-reducing measures that add weight.  I figure by the time I get to the Zulu 5, I should be happy as pie.

[piperpainter]

I think you're alone on this one. I would much rather speed and wearing a headset. Speed = time and time =Money. Sound=annoyance.......which I can dampen with a headset! 

Edit: I love the sound of airplanes! haha 

[triple8s]

I agree with Jose.......get rid of the recip fwf

http://youtu.be/aOcL6gUQO5A.

Much more pleasant sound

[cbarry]

Try driving any ground based vehicle at Mooney speeds and then try to carry on a conversation in the ground based vehicle as easily and relaxed as you can in the Mooney with decent headsets!

[Piloto]

I agree with Jose.......get rid of the recip fwf

http://youtu.be/aOcL6gUQO5A.

Much more pleasant sound

I don't know but that turboprop Caravan that swings by my hangar is three times noisier than the Islander twins.

 

José

[Piloto]

Try driving any ground based vehicle at Mooney speeds and then try to carry on a conversation in the ground based vehicle as easily and relaxed as you can in the Mooney with decent headsets!

Have you tried at the same speed with the engine off in your Mooney? Biiig difference!!!. Airliners fly at three times the speed of a Mooney and in the cockpit you can have a normal conversation without headsets.

 

Most of the engine noise in Mooney and others is due to the fact that the exhaust pipe is in front of the passenger rather than behind like is done on cars. If the exhaust pipe was located back in the tail cone you would be moving away from the sound wave instead toward it. There is plenty of space between the floor and the belly panels to locate an exhaust pipe toward the rear. If added noise reduction is desired you can put a real car muffler in the tail cone, It does not take much engineering just to try it. But it can make a difference on sales.

 

José   

[larryb]

Or how about a more comfortable way to deliver O2? Other than pressurization that is.

Sent from my iPad using Tapatalk

[Piloto]

Or how about a more comfortable way to deliver O2? Other than pressurization that is.

Sent from my iPad using Tapatalk

 

Take a look at Flyaware.com for turbo charged planes. Most of them are flown below 12,000feet instead above 18,000ft why is that? Talking to several turbo owners, including those with pressurized planes like the 601P I found this.

 

1. Trip is not long enough to justify higher altitude

2. They like to have the oxygen tank full than half full

3. The head winds at altitude are stronger

4. Burn more fuel climbing to the FLs

5. Build ups in the summer are over 20,000ft high.

6. I am not going to pay $100 for a refill at the FBO.

7. My cannula is plugged with nostrils stuff.

 

Some may argue with the above because they love to put in stuff in their nostrils, but please don't share it.

 

José 

[Guest]

Trying to figure out how to "block the noise", but don't know how to block your posts!

Clarence

[aaronk25]

Take a look at Flyaware.com for turbo charged planes. Most of them are flown below 12,000feet instead above 18,000ft why is that? Talking to several turbo owners, including those with pressurized planes like the 601P I found this.

1. Trip is not long enough to justify higher altitude

2. They like to have the oxygen tank full than half full

3. The head winds at altitude are stronger

4. Burn more fuel climbing to the FLs

5. Build ups in the summer are over 20,000ft high.

6. I am not going to pay $100 for a refill at the FBO.

7. My cannula is plugged with nostrils stuff.

Some may argue with the above because they love to put in stuff in their nostrils, but please don't share it.

José

That's interesting and I believe you that the majority fly below 12k but I've been drooling for a turbo bird for the past 2 years but I'm at the point that I'm not willing to switch airframes and go though the downtime and expense to fix 25 year old+ issues as I've already done that on my J just to get a similar HP bird.

If I could find the right 252 with 305hp rocket with TKS i think I'd be game. Going up to a 300hp bird might make sense to switch airframes and tackle "new" problems, but not willing to do it for just for turbo.....

Hey isn't the lower IAS at altitude worth some noise reduction??????

[Danb]

Jose..either it's still Apiil fools day or your nuts!,,!

[NotarPilot]

I totally disagree with Jose as well.

[aviatoreb]

I totally disagree with the motivation of the Mooney buyers and of the physics of the problem.

 

Mooney occupies the niche of the fastest certified single piston.  Give an option of 3 more knots or 10db lower…. I know what I would choose.  I agree my airplane is noisy but with my quality Bose head set I only notice if the batteries go dead and I need to change them.

 

You suggested that it is the exhaust outlet in front of the pilot that is the major source of noise.  I agree it could be contributing but I doubt moving it would do a lot.  There is the Mooney Liquid Rocket (only 5 of them) and they have an exhaust outlet in the tail.  Has anyone here ever been in one?  I would guess it is not significantly quieter.

 

My guess is that the two major contributions to the noise are:

-That prop in front is very very noisy sending back waves of pulsing air.

-The engine is bolted to a cage that is bolted to a steel cage that surrounds us.  Our lovely steel cages that give structural integrity in flight and for safety also probably resonate the engine noises all around us - for this reason I suspect that the Mooney is noisier than most single engine pistons out there.

 

Perhaps both could be mitigated with insulation and thicker windows etc.  But for me, when I have my headset on, and with my smooth 6 cylinder continental, my airplane sounds and feels whisper quiet.

[Joe Zuffoletto]

Mooney did make strides in this area before they stopped production. The cabin in my 2008 Acclaim is noticeably quieter than my 1998 Encore was, in spite of having 60 more horses under the cowling. When I compared them side-by-side I could see that Mooney added insulation to the door and ceiling panels, and the overall fit and finish of the Acclaim was superior to that of the Encore.

 

Still need a headset, though!

[Piloto]

It is obvious that noise is annoying to pilots. The very fact of the big headset market and intercoms just proves that. Some are willing to spend over $10K on ANRs and intercoms for just to talk to the passengers. The very first thing that a pilot in traing purchase is a headset. Have not seen this for driving cars. So yes noise is annoying to all here, that is why you have headset.

 

And yes noise comes from the engine. Just turn it off and see the difference. You do not even has to be inside the plane to notice the difference.

 

What is in your Mooney and others is merely a flame arrester not a muffler or silencer like in a car. There is simply no room in the engine compartment for silencer, neither on cars. That is why in cars the muffler/silencer is below or the back end of the exhaust pipe.

 

If Mooney wants to have an edge over the competition it needs to look into this before the competition does. Otherwise they are going to run in the same scenario as before with the same airplane. Being fastest has proven not to appeal to the majority. After all when have you purchased a car based on maximum speed, is not even on the specs.

 

The first thing that appeal to a prospective buyer is plane looks on the ground. Mooney and others have pretty much the same appeal on this. But Mooney can make an impressive show on the ground when it does not fart like the others. After all who like farts. It is easier to impress a crowd of 100 on the ground than three onboard. Particulary when comparing to your competitor on the ramp.

 

José   

[wishboneash]

The prop noise is significant. I think the engine noise is secondary. There is a big difference between a prop load and a gearbox load in a car. The prop tips reach almost supersonic speeds. Moreover, cars operate at 20-30% of their peak HP while our planes operate much closer to their max output.  Routing the exhaust to the rear is not going to do much IMHO. Just adds weight.

[BillC]

I agree with most of what you said Piloto. It's not just me who would like a quieter cabin, but my pax as well, including the rescue dogs I carry for delivery to new homes. (They won't wear the mutt muffs I got them). I fly WOT and 2400 for a noticably quieter cabin.

Like it or not noise legislation is coming. Have you flown into Torrence? Santa Monica? Fail to pull back MP/RPM at 500' and you'll get a letter or worse. In Sugarbush, VT, a glider operator there has installed 4 bladed Hoffmann props on his L-19's to calm noise complaints from residents. What about the noise complaints stemming from the Grand Canyon tour operators ? The list goes on and on. Aircraft manufacturers are going to have to address the noise problem sooner or later. Before I spend 500k on my next airplane, you can bet cabin noise will be part of the equation.

[Schinderhannes]

Have you tried at the same speed with the engine off in your Mooney? Biiig difference!!!. Airliners fly at three times the speed of a Mooney and in the cockpit you can have a normal conversation without headsets.

 

Most of the engine noise in Mooney and others is due to the fact that the exhaust pipe is in front of the passenger rather than behind like is done on cars. If the exhaust pipe was located back in the tail cone you would be moving away from the sound wave instead toward it. There is plenty of space between the floor and the belly panels to locate an exhaust pipe toward the rear. If added noise reduction is desired you can put a real car muffler in the tail cone, It does not take much engineering just to try it. But it can make a difference on sales.

 

José   

  

Obviously you are not a “Canard Piloto”

[Piloto]

The prop noise is significant. I think the engine noise is secondary. There is a big difference between a prop load and a gearbox load in a car. The prop tips reach almost supersonic speeds. Moreover, cars operate at 20-30% of their peak HP while our planes operate much closer to their max output.  Routing the exhaust to the rear is not going to do much IMHO. Just adds weight.

 

Good points to consider. But I learned in life what is not in the books is worth considering trying it because the outcome is not known yet. Otherwise we would still be reading the Bible.

 

José

[Piloto]

Obviously you are not a “Canard Piloto”

 

Canards do fart too. Maybe some Gas-X tablets in the fuel will help.

 

José

[Lood]

Well, somewhere, someone did something right. In 1982, a friend of mine bought a 1980 model M20K, with only 200hrs TT. He flew it for 2000hrs and it took him 31 years! He actually reached TBO somewhere around 2009 and replaced the engine with a factory reman at the time. Unfortunately, he has now become rather old and couldn't pass his medical anymore, so last year, he sold his 231.

 

About 4 years ago, he offered me a lift to go fetch a vehicle - about a two hour flight. I was frowned upon when I got into the airplane with my headset. He told me that he doesn't own a headset, because it was not required! I chucked my headset on the rear seat and off we went. To this day, I have never flown in any airplane that came close to this 231. The noise levels were similar to a passenger car and normal conversation was comfortably possible, in flight.

This guy still used the overhead speaker and hand held mic for all his radio work and all comms were loud and clear. If I didn't experience this first hand, I would not have believed that it could be remotely possible. The best part of all, was that this 231 was still stock standard, inside and out, like the day it left the factory.

[BigTex]

Wearing headsets is a relatively new thing. Back in the late '70's I obtained my PPL in a Warrior and it was all done without headsets. Just the hand held mic and the overhead speaker. In fact no one even used them at my flight school. Not until I started flying aerobatics in the early '80's did I start using headsets.

Of course, we didn't use seat belts in our cars either.... Times have really changed.