Police chopper noise levels

At 3 AM recently I happened to be up and about and I
heard a whining-whirring sound that turned out to be the
police helicopter circling over the public housing
project up the street. But...when that chopper comes
around in the daytime and evenings, it's much louder --
the well-known bupbupbup that lowers the quality of life
in this part of town. So how did they fly relatively
quietly at 3 AM and why don't they use that mode more
often?

--
Charles Packer
http://cpacker.org/whatnews
mailboxATcpacker.org

On Jul 7, 7:11 am, Charles Packer wrote:
At 3 AM recently I happened to be up and about and I
heard a whining-whirring sound that turned out to be the
police helicopter circling over the public housing
project up the street. But...when that chopper comes
around in the daytime and evenings, it's much louder --
the well-known bupbupbup that lowers the quality of life
in this part of town. So how did they fly relatively
quietly at 3 AM and why don't they use that mode more
often?

--
Charles Packerhttp://cpacker.org/whatnews
mailboxATcpacker.org

Diferent choppers, no doubt. The MD500 has no tailrotor and five
main rotor blades, and runs fairly quietly. Often used at night. The
other popular police copter is the Bell 206, which makes more noise
and that distinctive chop-chop sound.

Dan

On Jul 7, 7:11 am, Charles Packer wrote:
At 3 AM recently I happened to be up and about and I
heard a whining-whirring sound that turned out to be the
police helicopter circling over the public housing
project up the street. But...when that chopper comes
around in the daytime and evenings, it's much louder --
the well-known bupbupbup that lowers the quality of life
in this part of town. So how did they fly relatively
quietly at 3 AM and why don't they use that mode more
often?

--
Charles Packerhttp://cpacker.org/whatnews
mailboxATcpacker.org


"Quality of life" and "public housing project up the street" are not
phrases that you see together very often.

In article
,
wrote:

Diferent choppers, no doubt. The MD500 has no tailrotor and five
main rotor blades, and runs fairly quietly. Often used at night. The
other popular police copter is the Bell 206, which makes more noise
and that distinctive chop-chop sound.

Check before you SEND, Dan. :-))
Your are thinking of the 520N, NOTAR (No Tail roTAR)
Other versions of the 500 do have a conventional bladed tail rotor.

http://en.wikipedia.org/wiki/MD_Helicopters_MD_500

"Charles Packer" wrote in message
...
At 3 AM recently I happened to be up and about and I
heard a whining-whirring sound that turned out to be the
police helicopter circling over the public housing
project up the street. But...when that chopper comes
around in the daytime and evenings, it's much louder --
the well-known bupbupbup that lowers the quality of life
in this part of town. So how did they fly relatively
quietly at 3 AM and why don't they use that mode more
often?

Blue Thunder - Whisper Mode?

On Jul 7, 12:10 pm, John Smith wrote:
In article
,

wrote:
Diferent choppers, no doubt. The MD500 has no tailrotor and five
main rotor blades, and runs fairly quietly. Often used at night. The
other popular police copter is the Bell 206, which makes more noise
and that distinctive chop-chop sound.

Check before you SEND, Dan. :-))
Your are thinking of the 520N, NOTAR (No Tail roTAR)
Other versions of the 500 do have a conventional bladed tail rotor.

http://en.wikipedia.org/wiki/MD_Helicopters_MD_500

I was thinking of the original tailrotorless version, the
MD500N, but forgot the N:
http://www.deca-aviation.com/hawc1.htm
http://futurshox.net/aeroview.php?level=image&id=732
http://www.militarypictures.info/hel...d500n.jpg.html

Dan

On Jul 7, 10:01 am, wrote:
The
other popular police copter is the Bell 206, which makes more noise
and that distinctive chop-chop sound.

"Choppers"... go whop-whop-whop.
-----

- gpsman

On Jul 7, 10:01*am, wrote:
On Jul 7, 7:11 am,Charles wrote:

At 3 AM recently I happened to be up and about and I
heard a whining-whirring sound that turned out to be the
police helicopter circling over the public housing
project up the street. But...when that chopper comes
around in the daytime and evenings, it's much louder --
the well-known bupbupbup that lowers the quality of life
in this part of town. So how did they fly relatively
quietly at 3 AM and why don't they use that mode more
often?

--
Charles Packerhttp://cpacker.org/whatnews
mailboxATcpacker.org

* * * Diferent choppers, no doubt. The MD500 has no tailrotor and five
main rotor blades, and runs fairly quietly. Often used at night. The
other popular police copter is the Bell 206, which makes more noise
and that distinctive chop-chop sound.

* * * * *Dan

Hard for me to believe that D.C. police could afford two choppers.
Is there a Web site where the different makes are shown in profile so
I could learn to identify them?

--
Charles Packer
http://cpacker.org/whatnews
mailboxATcpacker.org

In article
,
Charles Packer wrote:

Hard for me to believe that D.C. police could afford two choppers.
Is there a Web site where the different makes are shown in profile so
I could learn to identify them?

Some cities did not have to purchase helicopters.
The federal government has a program to give surplus equipment to state
and local governments if they apply for it.
Former US Army OH-58 helicopters (military model of the Bell 206) are
one of the items which come available as they are retired from military
service and are placed on the surplus list.

Charles Packer wrote:

Hard for me to believe that D.C. police could afford two choppers.
Is there a Web site where the different makes are shown in profile so
I could learn to identify them?

--
Charles Packer
http://cpacker.org/whatnews
mailboxATcpacker.org


Strangely, the DC Metro police don't have anything on their webs site
about their aviation unit. (This is usually something that PDs brag
about.) They mention on their web site in one place that they have one
but no mention of the aircraft they use.

Being DC though they may use federal helos on an as needed basis in
addition to what they have in their own inventory.

Google "pictures of helicopters".