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