(Photo by Steve Wiggins)
Many people are familiar with the large flaps on airplane wings and their role in producing lift/drag. But have you ever noticed the smaller hinged sections on the outboard part of the wings? These are ailerons (French for “little wings”), and they are an important part of the modern airplane—albeit relatively unknown to the general population.
Ailerons work in opposition to bank an aircraft. For example, the right aileron may deflect upward and the left downward in order to cause a flight path to curve. Yes, contrary to popular belief, ailerons are largely responsible for turns—NOT rudders. The function of a rudder is primarily to control the position of an aircraft’s nose, but I digress. . .
Lift force (F) generated by ailerons is applied at the aerodynamic center of the aircraft some distance (L) from its center of gravity to create a torque defined as
Torque = F × L
about the plane’s center of gravity. Equal forces/distances result in a lack of net torque and unequal forces result in net torque rotating an aircraft about its center of gravity. All of this is good and well, but how did the aileron come to be? The answer begins with a particularly astute English gentleman!
While there are still conflicting claims over who first invented the aileron, some aspects of its history are irrefutable. Matthew Piers Watt Boulton patented a revolutionary lateral flight control system all the way back in 1868, but it was soon forgotten with practical aircraft still years away. In the mid to late 1800s, visionaries such as John Montgomery, Clement Ader, and Hugo Mattullath suggested a form of “wing warping” to control flight and applied the concept to kites with some success.
However, it was Wilbur and Orville Wright who combined wing warping with a rudder to counteract differential drag and achieve coordinated turns! With their radical combination of technologies and a forward-thinking patent including lateral control by mechanical means, the Wrights set in motion a new school of thought that French experimenter Robert Esnault-Pelterie subsequently expanded.
Esnault-Pelterie bridged the gap between wing warping and ailerons. He was concerned by the “excessive strains on the wiring” caused by wing warping designs of the Wrights, as explained in a January 1905 talk before the Aéro-Club de France. To alleviate the problem, Esnault-Pelterie’s original design featured two surfaces—deus gouvernails horizontaux (horizontal rudders)—placed between the wings, ahead of the leading edge.
The editor of L’Aérophile, a French aviation magazine described as the leading aeronautical journal of the world around 1910, pioneered the use of the word “aileron” in July of 1908. Soon thereafter, Henri Farman—inspired in the aftermath of Wilbur Wright’s flying demonstrations at LeMans in August of 1908—implemented the first recognizable modern aileron on his Farman III biplane! Farman was the first to make ailerons an integral part of the wing, with four flap-like ailerons at the outboard trailing edges of each set of wings.
Ailerons in use on contemporary airplanes echo those of times past, and it is important to consider the work of those early aviators that has allowed for such maneuverability in the present. Are you curious about another feature of our airplanes? Let us know in the comments below, and we’ll be sure to get the full scoop for you!
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A follow up, if I may. With the schedule extension coming up on August 11th, will there be changes to the current offerings around the weekend of March 5th, which already exists as a schedule? Earlier this year, this same weekend in March was included as "Spring Break." Will this be the same for 2016???
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Vicki... I'm so sorry that you're disappointed with our SAN to LIR offerings. I asked our networking planning folks and apparently the situation you described above is a result of the limited service we currently have in the HOU to LIR market--unfortunately we only offer a morning flight HOU-LIR, which is not late enough to connect from our first SAN-HOU flight. Going forward, as we gain expertise in the HOU international market, we will look to supplement our service with additional trips, pending each individual markets performance. So please keep us in mind when planning your international travel, as we would love to have you touch down in LIR on one of our beautiful jets.
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Airplanes are wonderfully complex machines. Fortunately for you, reading this article will ensure your flight-related vocabulary stays sharp and up-to-date. For today, consider the tail end of the quintessential Southwest Airlines airplane—the Boeing 737-300. No doubt you have noticed the slight elongation at the base of our planes’ vertical stabilizers and wondered about its significance. These additions are commonly referred to as “dorsal fins” and have emerged as the result of a fascinating history!
Our story begins with the very airplane Southwest relied upon in its early days—the Boeing 737-200. Note the steep descent from this plane’s vertical stabilizer as it joins the body. This particular model was first powered by Pratt & Whitney JT8D-15 and JT8D-17 powerplants that offered 15,500 and 16,000 pounds of thrust respectively. Though many Boeing 737-200 planes were subsequently equipped with more fuel efficient JT8D-9A powerplants, all three engine varieties were inefficient when compared to today’s modern engine standards and incapable of powering larger airframes.
The relatively small amount of thrust generated by these engines did allow pilots to maintain stability in the air without the dorsal fin addition of today. As the 1978 Airline Deregulation Act opened up a world of opportunity for Southwest however, it became clear that the company would need to find a larger plane with a more powerful engine. Enter the Boeing 737-300.
On December 17 th , 1984, Southwest’s first ever Boeing 737-300 debuted with the name The Spirit of Kitty Hawk to honor the anniversary of the Wright Brothers’ first flight (and is now on permanent display at the Frontiers of Flight museum in Dallas). This new plane featured high-efficiency CFM56 turbofan powerplants from CFM International—a collaborative effort between General Electric and France’s Snecma—rated between 20,007 and 22,008 pounds of thrust, depending on individual models.
The combination of a longer fuselage, higher engine thrust, and the need to maintain the directional control requirements both on the ground and in the air drove the need to increase the surface area of the vertical stabilizer. The best way to do this without increasing the height of the tail (which was considered a limitation due to existing infrastructure limitations, i.e., hanger door and ceiling heights), was to add the dorsal fin!
When it came time to design the NG, the increase in engine thrust levels required an even larger vertical stabilizer, and simply increasing the dorsal fin size would not suffice.
Boeing increased the height of the vertical stabilizer by ~5 feet to ensure adequate directional control capability with the higher thrust engines.
Are you curious about another feature of our airplanes? Do you ever wonder how your bags make it into your aircraft? Let us know in the comments below, and we’ll be sure to get the full scoop for you!
Photos by Richard West and Lari Pekurar
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Bright-eyed and innovative NoLimits Interns have been a welcome addition to Southwest every semester since 2001. While it is common for Interns to have parents or other relatives who work for the Company, we were delighted to discover a Southwest connection for one Intern this summer that dates all the way back to the first grade! Colleen Barrett, currently an Employment Intern in the People Department, has held a steady pen pal relationship with her namesake—Southwest’s President Emeritus Colleen Barrett—for more than a decade.
Their relationship began by happenstance.
At the age of seven, Intern Colleen remembers her mother reading about Southwest’s President and suggesting she write a “letter of congratulations” from a fellow Colleen Barrett. In true first grade fashion, the letter contained a smattering of introductory statements (e.g. “I like dogs”, “I play soccer”). No one in Intern Colleen’s family expected the overwhelmingly positive response that followed—on official Southwest stationery—from the President herself!
Intern Colleen is still moved by the way Colleen really put in effort to reach out to a seven year old.
Fast-forward a few months and the two began sending each other birthday cards, with Colleen even adding Intern Colleen to the Southwest birthday list! When Colleen was 11, Colleen invited her and her family to attend a Southwest Employee Appreciation Bash that was being held at the Country Music Hall of Fame near Colleen’s home in Nashville.
Intern Colleen remembers entering a room full of tuxedos and gowns dressed in the “denim skirt and boots” she associated with the venue, and she fondly recalls how Colleen took time to talk with her family despite the bustling event.
Their conversation continued throughout Intern Colleen’s middle and high school years.
Interning at Southwest was a decision Intern Colleen made independent of her ongoing exchange with Colleen.
She considers her longstanding connection to the Company an “added novelty” atop the internship and has grown to adore the Culture her pen pal so lovingly shaped. Prevailing in the face of a “fear that someone will inadvertently send an email to Colleen instead of herself," this story of dual Colleen Barretts is proof that sometimes all it takes to bring two people together is a bit of common ground and a kind word.
Do you share your name with another person? We’re interested in hearing your story. Let us know in the comments!
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