Spacepope From Vatican City, joined Dec 1999, 2813 posts, RR: 1 Reply 3, posted (12 years 9 months 15 hours ago) and read 2373 times:
They are indeed strakes. From what I understand, they serve the same purpose as winglets, they're just oriented differently. They smooth out the airflow over the wingtip so that the vortexes do not sap so much energy, and cause too much drag. Perhaps someone can get more technical than this, I'm just a geologist, and it's been about 3 years since my last class in fluid flow. reynolds number? Froude number? I couldn't tell you.
Western727 From United States of America, joined Jan 2007, 643 posts, RR: 4 Reply 5, posted (12 years 9 months 15 hours ago) and read 2353 times:
OPNLguy, that photo was from an A32O or an A319. And I'm not talking about static wicks. I'm talking about the strakes (the smashed-winglet lookin' things). Spacepope, thanks for your info. I'd love to hear more.
Spacepope From Vatican City, joined Dec 1999, 2813 posts, RR: 1 Reply 14, posted (12 years 9 months 14 hours ago) and read 2309 times:
A strake is what you call the part of an aircraft that blends the wing into the body. Look an an F-16, those are called Leading Edge Strakes. The give significant drag reduction and contribute to lift.
The raked wingtips help smooth out the air in the area where the low pressure air above the wing may mix with the high(er) pressure air from below the wing. think of it as keeping it from spilling out from uder the wing. Many techniques have been tried to eliminate this problem. Earlier attempts include wing fences and winglets. This Boeing mod on the 764 is just one more technique that appears to work.
Now for all you engineers- does the raked wingtip pose any significant advantage over a vertical winglet?
Mr Spaceman From Canada, joined Mar 2001, 2786 posts, RR: 9 Reply 15, posted (12 years 9 months 14 hours ago) and read 2305 times:
You can find a "Strake" on each side of the belly of a U.S. Marines "Harrier" fighter jet. They look like long "Wing Fences" only upside-down on the belly. I believe they serve the same purpose, they help control airflow direction. ---Maybe these "Raked" wingtips simply contain the wire harnesses for the tip lighting on wings with "extended" range fuel tanks. [I couldn't tell ya!]
Ual747 From , joined Dec 1969, posts, RR: Reply 18, posted (12 years 9 months 3 hours ago) and read 2252 times:
I'm not a physics major; however, the raked wingtips do provide an advantage over the vertical ones. Basically, the raked wingtips are an extension of the wing itself. While discouraging overspill of high pressure air onto the top of the wing where low pressure air is present, they also, by being horizontal, give extra lift, kinda like an extension of the wing.
Western727 From United States of America, joined Jan 2007, 643 posts, RR: 4 Reply 21, posted (12 years 8 months 4 weeks 1 day 17 hours ago) and read 2237 times:
Yes, that's exactly the attitude I'm talking about. My question for you is: How does one ascend to your station in the aviation community, Cedarjet and Jetpilot, without hearing the word 'strake?' I'm just a private pilot, and I've seen the word used commonly in aviation books, magazines, websites, etc. One article stands out particularly. The topic was the Beech 1900D. One can't really describe that airplane *without* using the word 'strake.' Now, my concern is not that you don't know what a strake is. My concern is that you voiced your confusion in such an impolite manner (and that goes for both of you). It was, after all, a simple question. And I don't recall doing anything to offend either of you on any prior occasion. So I ask again: Why lash out at me for trying to educate myself? Why lash out at me at all? If you'd like to know what a strake is, try, just for a moment, to step out of your arrogance, and do some research.
A/c train From United Kingdom, joined Jun 2001, 501 posts, RR: 4 Reply 22, posted (12 years 8 months 4 weeks 1 day 16 hours ago) and read 2234 times:
Well said Western 727, when im being taught by pro AMT's there generally ' TOP BLOKES' , who have enough time for you and DONT barf at you when you are confused, or pronounce something wrong , I have learnt so much by being with these people and would always listen to what they say , CUT THE KNOW IT ALLISM no one knows everything !and as 310 said to me once were all here to learn.
FDXmech From United States of America, joined Mar 2000, 3251 posts, RR: 36 Reply 23, posted (12 years 8 months 4 weeks 1 day 16 hours ago) and read 2232 times:
Actually "strakes" are a valid nomenclature. Example: observe the forwrd fuselage below the rear cockpit window and above the nose gear on the MD80. Those short winglike (reminds me of a popsickle stick) appendages are called "strakes".
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2 Reply 24, posted (12 years 8 months 4 weeks 1 day 3 hours ago) and read 2203 times:
"They're not strakes. What the hell is a strake..."
GREat Attitude. The term wasn't covered in the degree program at Bastardization of Science U...Probably shouldn't bring up the phrase "REynold's #" either...How bout "Payfertraining?" Now!! Here comes the dissertation...
Spacepope gives a good description. In particular, strakes maximize high alpha capability on fighter aircraft, and give the f16/18 (and of course Mig29/Su27 etc) the hooded cobra look.
AW&ST gave a good account of why the raked tips were selected for the 76-400 vs winglets, which essentially boiled down to the fact that the winglets required beefier structure to support, but gave around 3% decrease in drag at cruise altitudes only (a la typ winglet). The raked tips give about a 1% decrease in drag in all flight regimes, did not require any strengening of the structure, and are CDL able. If one gets dinged, take off the other, adjust the perf numbers, and go fly.
25 Srbmod: Boeing's calling them raked winglets. They had experimented in a wind tunnel with various winglet designs, (blended, vertical, raked) and the raked de
26 Flyf15: A "Strake" is basically any fin type chunk of metal that isn't part of the basic wing, horizontal, or vertical tail surfaces that contributes to the s