Noise Cancelling headsets - metro

Hawker · Post by **Hawker** » Mon Nov 06, 2006 4:33 pm

Just looking for the prefered noise cancelling headset on a metro 2 to get rid of the lovely whine. Bose or DC's??? thanks

YWGVOR · Post by **YWGVOR** » Mon Nov 06, 2006 5:43 pm

earplugs?

oldtimer · Post by **oldtimer** » Mon Nov 06, 2006 9:38 pm

A good DC and ear plugs.

intheknow · Post by **intheknow** » Wed Nov 08, 2006 10:09 pm

the noise cancelling don't work that well on a 2. Something about the frequency of the prop blades being higher than the cancelling range. I used to use custom musician's earplugs from someplace that sells hearing aids. They cost about $180 or so, but you don't have to pay for a new battery every 20 hrs and they fit very comfortably under your headset.

the_professor · Post by **the_professor** » Wed Nov 08, 2006 10:24 pm

intheknow wrote:the noise cancelling don't work that well on a 2. Something about the frequency of the prop blades being higher than the cancelling range. I used to use custom musician's earplugs from someplace that sells hearing aids. They cost about $180 or so, but you don't have to pay for a new battery every 20 hrs and they fit very comfortably under your headset.

Is it simply a difference in insulation between the 2 and the 3? Over ATC speakers the 3's sound like a King Air. The 2's sound like someone forgot to the latch the door, and/or opened a cockpit window in order to let the bong smoke out. (I assume that's why you guys sometimes miss so many radio calls)

ditshisturber · Post by **ditshisturber** » Wed Nov 08, 2006 10:29 pm

the_professor wrote:
intheknow wrote:the noise cancelling don't work that well on a 2. Something about the frequency of the prop blades being higher than the cancelling range. I used to use custom musician's earplugs from someplace that sells hearing aids. They cost about $180 or so, but you don't have to pay for a new battery every 20 hrs and they fit very comfortably under your headset.
Is it simply a difference in insulation between the 2 and the 3? Over ATC speakers the 3's sound like a King Air. The 2's sound like someone forgot to the latch the door, and/or opened a cockpit window in order to let the bong smoke out. (I assume that's why you guys sometimes miss so many radio calls)

The Metro II 3 bladed prop turns at 2000 RPM at 100%, while the Metro III 4 bladed prop spins at 1591 RPM at 100%... that is the big difference right there. Most cargo machines have a lot of the interior and insulation stripped down, but IIs are exceptionally noisy (Pax or cargo).

the_professor · Post by **the_professor** » Thu Nov 09, 2006 12:37 am

ditshisturber wrote:
the_professor wrote:
intheknow wrote:the noise cancelling don't work that well on a 2. Something about the frequency of the prop blades being higher than the cancelling range. I used to use custom musician's earplugs from someplace that sells hearing aids. They cost about $180 or so, but you don't have to pay for a new battery every 20 hrs and they fit very comfortably under your headset.
Is it simply a difference in insulation between the 2 and the 3? Over ATC speakers the 3's sound like a King Air. The 2's sound like someone forgot to the latch the door, and/or opened a cockpit window in order to let the bong smoke out. (I assume that's why you guys sometimes miss so many radio calls)
The Metro II 3 bladed prop turns at 2000 RPM at 100%, while the Metro III 4 bladed prop spins at 1591 RPM at 100%... that is the big difference right there. Most cargo machines have a lot of the interior and insulation stripped down, but IIs are exceptionally noisy (Pax or cargo).

I thought all PAG's machines now ran on the 4 blade props though? Didn't PAG engineer that design with Hartzell?

Turkey · Post by **Turkey** » Thu Nov 09, 2006 7:20 am

4 bladed props or not, they're still turning at 2000 RPM in a Metro II vs 1591 RPM (1543 in cruise) in a 3 or 23.

the_professor · Post by **the_professor** » Thu Nov 09, 2006 8:29 am

Turkey wrote:4 bladed props or not, they're still turning at 2000 RPM in a Metro II vs 1591 RPM (1543 in cruise) in a 3 or 23.

So the 3's 4 bladed props are still longer than a 2's 4 bladed prop, hence the lower rpm? (incidentally, 3+4+2+4 = 13)

Turkey · Post by **Turkey** » Thu Nov 09, 2006 7:41 pm

I'm not entirely sure if you're asking a question...

...It has to do with the engine that the props are attached to. Metro IIs (-6 or -10 engines) turn at 2000 RPM. Metro IIIs and 23s (-11 or -12 engines) turn at 1591 RPM. (You don't set Prop RPM in a garrett engine anyways, you set Engine RPM. In percent of maximum. i.e. 100% for takeoff)

...And yes, the blades are longer on the III and 23 than the blades on the II. But the longer blades are the RESULT of the slower turning engines, not the cause.

...You're right, 3+4+2+4 = 13. But you've completely lost me otherwise.

Turkey · Post by **Turkey** » Thu Nov 09, 2006 7:49 pm

To answer an honest question. Earplugs. Are a must. Especially in a II. Less so in a 3. Even less, but still a good idea in a 23.

Highflyinpilot · Post by **Highflyinpilot** » Thu Nov 09, 2006 7:52 pm

Just dont fly, that's guarranteed to work

gonefishin' · Post by **gonefishin'** » Fri Nov 10, 2006 12:06 am

Lightspeed XL15's... worked great for 3 years on a metro II and III.

ditshisturber · Post by **ditshisturber** » Fri Nov 10, 2006 6:22 am

Turkey wrote:I'm not entirely sure if you're asking a question...

...It has to do with the engine that the props are attached to. Metro IIs (-6 or -10 engines) turn at 2000 RPM. Metro IIIs and 23s (-11 or -12 engines) turn at 1591 RPM. (You don't set Prop RPM in a garrett engine anyways, you set Engine RPM. In percent of maximum. i.e. 100% for takeoff)

...And yes, the blades are longer on the III and 23 than the blades on the II. But the longer blades are the RESULT of the slower turning engines, not the cause.

...You're right, 3+4+2+4 = 13. But you've completely lost me otherwise.

Assuming with IIs and IIIs that we have -10s and -11s, aren't the engines are both turning at the same speeds at 100% - about 41,730 RPM? I understand that is what a -11 does, what is the actual engine RPM of a -10 at 100?

Through the reduction gearing, we end up with blades spinning at either 2000 rpm or 1,591.

Just curious

. ._ · Post by **. ._** » Fri Nov 10, 2006 6:42 am

Did someone say "metro"?

-istp

Turkey · Post by **Turkey** » Fri Nov 10, 2006 7:47 am

ditshisturber wrote:Through the reduction gearing, we end up with blades spinning at either 2000 rpm or 1,591.

Quite correct. I was only speaking of the end result. i.e. what the pilots and passengers hear in the cabin.

ei ei owe · Post by **ei ei owe** » Fri Nov 10, 2006 5:14 pm

gonefishin' wrote:Lightspeed XL15's... worked great for 3 years on a metro II and III.

How's the durability and workmanship? How's the noise reduction when the bats run down? Are they comfortable?

the_professor · Post by **the_professor** » Sat Nov 11, 2006 1:19 pm

Turkey wrote:
ditshisturber wrote:Through the reduction gearing, we end up with blades spinning at either 2000 rpm or 1,591.
Quite correct. I was only speaking of the end result. i.e. what the pilots and passengers hear in the cabin.

I'm still confused.

I understand longer blades are rotated slower. Doesn't this still result in roughly the same speed at the tip of the longer blade?

Why does the III sound so much quieter over the radio, yet I can't tell the difference (without looking up) when a II or a III flies over me when I'm on the ground? The buzz sounds the same from the ground to me.

Merlinman · Post by **Merlinman** » Sat Nov 11, 2006 1:35 pm

metro2 prop tips travel 25% faster than the 3 at maximum RPM. or so the math says....

and I'm guessing the 3 props are 108" and the 2 is 97"

ei ei owe · Post by **ei ei owe** » Sat Nov 11, 2006 1:42 pm

the_professor wrote:
Why does the III sound so much quieter over the radio, yet I can't tell the difference (without looking up) when a II or a III flies over me when I'm on the ground? The buzz sounds the same from the ground to me.

You can tell a II and a III when on the ground. One's a low hum and the other's a high pitch scream.

bandit1 · Post by **bandit1** » Sat Nov 11, 2006 8:55 pm

they're both loud as hell.

gonefishin' · Post by **gonefishin'** » Sat Nov 11, 2006 11:01 pm

ei ei owe wrote:
gonefishin' wrote:Lightspeed XL15's... worked great for 3 years on a metro II and III.
How's the durability and workmanship? How's the noise reduction when the bats run down? Are they comfortable?

Only had one problem in 3 years, sent them to LS in PDX and they were back in 2 days, fully reconditioned. When the batts go they are noisy, so its good to have a spare set of AA's. Usually get about 50 hours per set. As for comfort, very good, except when its very cold, as the gel ear pads get rock hard.

Merlinman · Post by **Merlinman** » Sun Nov 12, 2006 9:42 pm

gonefishin' wrote:
ei ei owe wrote:
gonefishin' wrote:Lightspeed XL15's... worked great for 3 years on a metro II and III.
How's the durability and workmanship? How's the noise reduction when the bats run down? Are they comfortable?
Only had one problem in 3 years, sent them to LS in PDX and they were back in 2 days, fully reconditioned. When the batts go they are noisy, so its good to have a spare set of AA's. Usually get about 50 hours per set. As for comfort, very good, except when its very cold, as the gel ear pads get rock hard.

funny... I've flown with two guys who raved about their lightspeed headsets and said how good they were.... both headsets broke the very first day I flew with them. They seem to be built with a low quality composite or plastic frame that always breaks after a couple years. The circuit boards crapped out on one and the ear pieces fell off of both sets. Funny as hell to watch them talk on the radio trying to hold their headset together.

One guy had his 10 year old DC's fall apart once too.. funny as hell to watch no matter what the headset....

Liftdumper · Post by **Liftdumper** » Mon Nov 13, 2006 8:18 am

Chop your head off you're flying a metro