Chinook Question

[rusty_c]

Can anybody tell me why I regularly see Chinooks flying northbound over the Waltham Abbey area? Thanks

[The Nr Fairy]

Because they're too big to fit on the M25 ?

[zerospeedit]

Well it sounds like you're spending too much time in the Waltham Abbey Area!

It also happens to be one of the exit routes from the London CTR for Wokkas that have taken the "short cut" across The Smoke from their base in Hants.
:ok:

[rusty_c]

well i work there!! Where are they off to?

[GashCrewman]

Anywhere! It's a bit like asking where are all of the cars on the M25 off to!!! ;) It is just part of the route through London to deconflict with all of the airports.

[Agaricus bisporus]

Could be on a Navex route. I have Chinooks, Apaches and the occasinal Lynx passing my place regularly, all on the same route and almost always in the same direction. It is not on any obvious direct between stations or avoiding other airspace so conclude nav route.

[pulse1]

So here's another Chinook question (could be applied to Lynx as well):

Why can I hear a Chinook/Lynx approaching from miles away but, once they have flown over me, the sound fades quite rapidly? In other words, I can hear a Chinook coming towards me from about 2 miles away, but can't hear it going away from me beyond about half a mile.

Obviously wind direction will have some effect but this is too regular to be just down to wind. I think it applies to all helicopters but it is far more noticeable for the distinctive sound of the Chinook and Lynx.

[sikrosky]

The short answer is that noise propagation from a rotor in forward flight is highly asymmetric. The reason for this is "thickness" noise generated by the advancing blades which propagates primarily in the direction of travel. This google search would be the place to start for the long answer. http://www.google.com/search?hl=en&safe=off&q=helicopter+noise+thickness&btnG=Search