This is the place where the majority of the warbird (aircraft that have survived military service) discussions will take place. Specialized forums may be added in the new future
Tue May 12, 2009 12:11 pm
http://www.airpowerexpo.com/
I'm taking a C-17 down there for a static display. If anybody comes out be sure and stop by and say howdy.
Last edited by
Brad on Thu May 14, 2009 9:47 pm, edited 1 time in total.
Tue May 12, 2009 1:19 pm
Brad wrote:http://www.airpowerexpo.com/
I'm taking a C-17 down there for a static display. If anybody comes out be sure and stop by and say howdy.
Brad, what is the reason for the little 'delta wings' on each side of the engines?
Tue May 12, 2009 1:19 pm
looks like it will be a good show. BUT i'm working saturday.
Wed May 13, 2009 9:12 pm
The small wings on each side of the C-17's engine nacelles are vortex generators. Most aircraft have them on the wings, but on the C-17 they are on the sides of the nacelles.
Walt
Thu May 14, 2009 9:46 pm
Walt has pretty much summed it up.
From the Hymnal (Structural Repair Manual): "The strakes help reduce turbulence at the wing leading edge during high angle-of-attack flight."
From the Bible (Flight Manual) "The nacelle strakes improve wing aerodynamic efficiency and the fuselage strakes reduce cruise drag. Cruise performance is therefore improved."
Thu May 14, 2009 10:57 pm
For those of you interested
www.airshowtime.com will be webcasting the show live.
Fri May 15, 2009 3:17 am
Thank you, RareBear and Brad.
Unusual (to me) to see them on engines.
Fri May 15, 2009 8:21 am
The thrust line of the engines is higher up than on most nacelle equipped airliners (as well as being mounted closer to the wing) and consequently have a greater impact on the wing's aerodynamics at higher angles of attack. The 737-300 and later series of that aircraft have much the same issues and have vortex generators on their nacelles as well. Check out:
http://www.aerospaceweb.org/question/ae ... 0255.shtml
http://old.smartcockpit.com/operations/ ... rators.PDF
HTH! Mark
Fri May 15, 2009 9:29 am
Good links Mark!

I thought I knew about vortex generators, but was unaware they were in such widespread use on engines. Quite surprised and impressed at the amount of benefit they offer.
Fri May 15, 2009 2:38 pm
They are Nacelle Aerodynamic Strakes. Yes, they control the airflow at high angles of attack.
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