News First Flight of Boeing 787 - live webcast

[tl8]

The chevrons on the exhaust are there for noise reduction.

Only because noise is wasted energy...

 

[Hielor]

Only because noise is wasted energy...

All of the literature talks about the chevrons reducing noise, nothing about the chevrons being more efficient.

 

[tl8]

All of the literature talks about the chevrons reducing noise, nothing about the chevrons being more efficient.

Well noise is a by-product, so reducing noise must reduce the energy somewhere. Now it could be that the energy that the noise comes from is now turned into heat energy or kinetic energy via air currents. Wether this is intentional I don't know.

 

[SiberianTiger]

This curious diagram shows how much the composite wing of a 787' bends under different stresses applied:

Somehow I think it's good for shooting arrows!

:sos:

 

[Andy44]

Noise is a big problem in congested areas and airlines pay through the nose for fines, so there is more to noise reduction than just efficiency, I'd bet.

 

[NukeET]

Yesterday, I had just arrived at the Museum of Flight (in Seattle, next to Boeing Field) when I witnessed a taxi test of the 787. Couldn't help the chain link fence...I was in a bit of a hurry since the thing was moving.

What is hanging from the vertical stabilizer? It looked like a remnant of a parachute, while earlier posts in this thread called it a "anti-spin device" or a "photo drone".

 

[Urwumpe]

Looks like a anti-spin device. Can't tell you what it exactly is though and why it is installed there. Usually, it is not deployed all the time, but fired by a mortar, when the plane develops an unstoppable spin during test flights.