C:My DocumentsMy PicturesDSC_0106.JPG
hello
While flying home from Rome on this Ryanair flight,i took this photo of the engine to this B738, and was wondering what is this peace of metal that is sticking out. I didn't want to start asking this questions while on board just in case it might worry the pax.
Any help on this would be greatfull.
cheers
dave
Moderators: richierich, ua900, PanAm_DC10, hOMSaR
Help With This Pic Pls
David.S cavanagh since 1961,if you can do better,then show me.
RE: Help With This Pic Pls
Hi,
Maybe uploading the image to the servers would be helpful in your quest for answers
Spru!
Maybe uploading the image to the servers would be helpful in your quest for answers
Spru!
E=Mc2
RE: Help With This Pic Pls
If you are talking about the fin looking device that's the vortex generator. It's purpose is to smooth the airflow going over the wing. Hope this helps.
Never take financial advice from co-workers.
RE: Help With This Pic Pls
| Quoting Express1 (Thread starter): and was wondering what is this peace of metal that is sticking out. |
If you look closely, 99% of all passenger planes with underwing engines have that little piece of metal sticking out. It only really is effective at high angles of attack.
RE: Help With This Pic Pls
That would be a strake, who's purpose is to disrupt airflow durring certain flight regimes....if you ever fly on a 737 in high humidity conditions, you get a wonderful visualization of what it does to the airflow IIRC, at high angles of attack, it creates a nice high energy vortex that goes right over the top of the wing.
IIRC, at high angles of attack, it creates a nice high energy vortex that goes right over the top of the wing.Celebrating the birth of KELPkidJR on August 5, 2009 :-)
RE: Help With This Pic Pls
Photo © Rolf Wallner
Mounted on the Inboard side of the Cowl....Its a type of Vortex Generator.Called a Strake.
regds
MEL
I may not win often, but I damn well never lose!!! 
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- grandtheftaero
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RE: Help With This Pic Pls
More info from Dick Shevell's AIAA paper "Aerodynamic Bugs: Can CFD Spray Them Away"
"DC-10 wind tunnel tests showed a significant loss in maximum lift
coefficient in the flap deflected configurations, with landing slat
extension, compared to predictions. This resulted in a stall speed
increase of about 5 knots in the approach configuration. The initial
wing stall occured behind the nacelles and forward of the inboard
ailerons. The problem was traced by flow visualization techniques to the
effects of the nacelle wake at high angles of attack and the absence of
the slat in the vicinity of the nacelle pylons. The solution was
developed in the NASA Ames Research Center 12 ft. pressurized tunnel and
turned out to be a pair of strakes mounted forward on each side of the
nacelles in planes about 45 degrees above the horizontal. The final
strake shape was optimized in flight tests. The strakes are simply
large vortex generators. The vortices mix the nacelle boundary layer air
with the free stream and reduce the momentum loss in the wake. The
vortices then pass just over the upper surface of the wing, continuing
this mixing process. The counterrotating vortices also create a downwash
over the wing region unprotected by the slat, further reducing the
premature stall. The effect of the strakes is to reduce the required
takeoff and landing field lengths by about 6%, a very large effect."
http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=43846
"DC-10 wind tunnel tests showed a significant loss in maximum lift
coefficient in the flap deflected configurations, with landing slat
extension, compared to predictions. This resulted in a stall speed
increase of about 5 knots in the approach configuration. The initial
wing stall occured behind the nacelles and forward of the inboard
ailerons. The problem was traced by flow visualization techniques to the
effects of the nacelle wake at high angles of attack and the absence of
the slat in the vicinity of the nacelle pylons. The solution was
developed in the NASA Ames Research Center 12 ft. pressurized tunnel and
turned out to be a pair of strakes mounted forward on each side of the
nacelles in planes about 45 degrees above the horizontal. The final
strake shape was optimized in flight tests. The strakes are simply
large vortex generators. The vortices mix the nacelle boundary layer air
with the free stream and reduce the momentum loss in the wake. The
vortices then pass just over the upper surface of the wing, continuing
this mixing process. The counterrotating vortices also create a downwash
over the wing region unprotected by the slat, further reducing the
premature stall. The effect of the strakes is to reduce the required
takeoff and landing field lengths by about 6%, a very large effect."
http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=43846