Could some please stop confusing turbulent boundary layers with separated flow... a turb b.l. is not going to do that, heavily separated flow might cause buffeting & noise though

Turbulent boundary layers are much more resistant to separation than laminar ones.. some obviously know this, quite a few don't. That's why we stir up the flow in the boundary layer (with say voretx generators), to get an early transition to turb b.l and re-energise it.

It's interesting some of the differences in minimum speeds quoted for flow modifiers around the nacelle/wing junctions - they're quite significant.

To whoever it was suggested that Boeing 'invented' the nacelle strake or vortex generator - sounds like another re-writing of history to me :rolleyes:

Sorry, Harry, wrong terminology... blame extreme age of poster.

CJ

Back in the late 70's when I briefly worked for a DC10 operator I came across a file of newsletters produced by Douglas (I think they were titled "Know Your DC10" or something similar). One of them discussed the reason for nosecowl strakes which was as described in depth in several earlier posts (disturbed airflow off the nosecowl in the landing configuration interacting with the gap in the LE slats for the pylon was going to result in missing their target landing distance due to too high a reference speed). According to the article they started out with a strake on the inboard side that extended from the nosecowl right across the fan cowl and then shortened it bit by bit until they established the minimum size of strake that allowed them to acheive their target landing distances. Another stake was installed on the outboard side to make the nosecowl fully interchangeanle L & R.

And then one operator noticed the techs were leaving spanners, etc. in the valley between the cowl and strake, and so removed the latter to prevent FOD. :}

FNP's picture in post 28 has 4 CFM56s, but isn't a 340 as i) judging by the engines, the wing is too small ii) the wing has vortex generators which the airbus FBW designs don't and iii) that wing has Kruger style LE devices which airbuses don't. It's either a 707 airframe which would make it an E3 or a C135 derivative or a DC8 conversion. The CFMs weren't certified on civil 707s and as the engines have the CFM logo which wouldn't be put on a military aircraft, I reckon it's a DC8.

Not a DC-8 as none had leading edge flaps/slats. By the vortex generators on the wing it has to be a 707. Not up to speed re Airbus but think that they would have an extendable leading edge like a B767.

They do. In fact, I think it's this aircraft. The one and only prototype 707-700.

http://www.simviation.com/hjg/aircra...n707qt_NEW.jpg

A website on the 707s history mentions that it wasn't continued because it would compete with the 757. However, someone I know who was partly responsible for the introduction of the KC135R (with CFM56s) into the USAF mentioned that the aircraft had handling issues which Boeing realised would make civil certification difficult.

oic...
 

Dan Winterland, thanks man...