All after.

I used to "know of" an operator that would change their tail number for SNA and SMO operations in Lear's. Used to be the 3 strikes rule, 3 strikes and change the tail number, lol. Mid 90's or so.

I dont know anything noisier than a MU2.
A jet wont meet your specs. A TBM 850/900 will do all except on price and speed.




Wrong on almost every axis.

Not jet, not short runway, not cheap, and to top it off, noisier than an MU2!

Mike C.

Many things noisier in flight. P210, C185, Queen Air, many older Barons and Bonanzas, jets, Piaggio, etc.

Not many things noisier in taxi, though.

Im saying on the ramp standing still or taxiing, the MU2 is brutal.





Many things noisier in flight. P210, C185, Queen Air, many older Barons and Bonanzas, jets, Piaggio, etc.

Not many things noisier in taxi, though.

Piaggio is ridicuously loud in flight or on the ground. Not sure about cabin noise.
At KCMA we had avantair. It caused the locals to notice the airport and start complaining. Avantair has since left the airport and things have calmed down.

That airplane is a neighbors nightmare!

Could be if I get more $$$.


That's a step back. If I needed the cabin space, then I'd get a long body MU2 before considering a PC-12.


Sounds like what I have, except it goes faster and has twin redundancy.

Mike C.

Piaggio banned at SMO, MU2 not.

Piaggio noise signature causes problems:

https://www.google.com/search?q=piaggio ... complaints

MU2 is only noisy on the ground, thus not as bad to neighbors.

Mike C.

Too big. 56 ft wingspan, 18 ft tall, 55 ft long, 18,000 lbs.

If I could have a 75% scale version of that...

Mike C.

What this thread is teaching me is that the cost and capability of my MU2 is phenomenally good.

A Phenom 100 gets close...

Mike C.

What this thread is teaching me is that the cost and capability of my MU2 is phenomenally good.

A Phenom 100 gets close...

Mike C.

No question about the noise on the ramp -- but that's outside the plane. Inside the plane I find it quieter than a King Air.

Issue with noise on the ramp is the Ground Idle speed. Since a PT-6 is aerodynamically coupled to the turbine (vice mechanically as on the Garretts), it Ground idle can be a true idle speed on the engine. Since the Garrett is spinning that prop, idle needs to be higher to keep the engine above a bog down rpm. Even worse (depending on your point of view), the original engines idled at a lower rpm but it turns out that was a harmonic that could cause cracks, so ground idle was raised to 77% rpm solving the crack problem but meaning the ground idle is a bit higher (and thus noise).

Inside the cabin, the plane is quite quiet. I can talk to the copilot at a normal speaking voice with no problem...or speak to the pax in back. No one wears headphones in the back on my plane -- the cabin noise is similar to what you'd have in a Saab 340 or ATR (noise than a jet but much quieter than a piston or most of the King Airs). I think part of the reason is the prop location -- the props are much farther forward on a King Air than an MU-2 long body. As a result, you get more prop wash and noise against the cabin...

No question about the noise on the ramp -- but that's outside the plane. Inside the plane I find it quieter than a King Air.

Issue with noise on the ramp is the Ground Idle speed. Since a PT-6 is aerodynamically coupled to the turbine (vice mechanically as on the Garretts), it Ground idle can be a true idle speed on the engine. Since the Garrett is spinning that prop, idle needs to be higher to keep the engine above a bog down rpm. Even worse (depending on your point of view), the original engines idled at a lower rpm but it turns out that was a harmonic that could cause cracks, so ground idle was raised to 77% rpm solving the crack problem but meaning the ground idle is a bit higher (and thus noise).

Inside the cabin, the plane is quite quiet. I can talk to the copilot at a normal speaking voice with no problem...or speak to the pax in back. No one wears headphones in the back on my plane -- the cabin noise is similar to what you'd have in a Saab 340 or ATR (noise than a jet but much quieter than a piston or most of the King Airs). I think part of the reason is the prop location -- the props are much farther forward on a King Air than an MU-2 long body. As a result, you get more prop wash and noise against the cabin...

One reason the PT6 efficiency suffers as compared to the TPE331 is the intake reverse flow path.

But the compressor is not really the MU2 problem. All TPE331 equipped airplanes have that and they sound somewhat different. The issue with the MU2, I believe, is a sort of ground resonance setup by the extremely short tail pipe (another efficiency benefit, alas), the lack of airflow by the prop in ground idle, and the sound being under the wing.

The 441, Merlin don't have it as bad with the engine above the wing and longer tail pipes. The Commanders have longer and bent tail pipes. Only the MU2 has engine under the wing forming a sound chamber with the ground and very short tail pipes.

Once there is air flow by the prop, the moving air isolates the exhaust from the rest of the air and that MU2 whine goes away. In the air, you don't really hear the first compressor wheel.

The above suggests you could make an alternate MU2 tailpipe which is a bit longer and has a variable end like this:

The chevron trailing edge prevents the pipe from being tuned to a particular frequency. I think such a tail pipe would have minimal impact on the MU2 performance and could greatly reduce the ground idle noise signature.

No lack of potential projects have I.

Mike C.

It doesn't matter if it's a merlin, turbo commander or mu-2, it's flat out loud. Tail pipes may make a difference, but that compressor out front is a noise maker for sure. Surprisingly quiet inside, especially the merlin.