Airbus A300/A310

12-31-2002, 11:25 AM

Last weekend I flew on both an A310 and A300-600R (first one ever for me!) and noticed something odd, and at the time a bit unnerving: flaps aren't used for takeoff! Can any of you engineers out there explain how the wing on the A300 generates enough lift for takeoff without the use of flaps? Thanks.

Phugoid · 12-31-2002, 12:58 PM

The A-300 was initially developed as a short range jet, with stage lengths between 1 and 2 hours. The optimum altitude is in the mid twenties and the wing is not designed to be super efficient at high speed and high altitude. Being built for the shorter stage lengths, a high lift, low speed wing was more optimal. Though you do not need flaps for takeoff with the A-300 b2, b4, 600, slats are required. A flaps up takeoff requires greater runway length due to increased Vr speed. A flaps up takeoff also gives a better climb gradient, and generally allows more weight to be carried, as it is not second segment climb restricted.

Boeing tends to design wings for high speed flight, with the exception of the 737, the 72 has a crit mach of .90 and the 74 is also around that number, either .9 or .92. When a high speed wing is desirable a decrease in drag is required and lift in the lower speeds is sacrificed. Flaps are installed to relieve this deficiency during the slow speed region of takeoff and approach. As for why a flaps up takeoff cannot be safely accomplished with a 73 original/ classic, is because it has an old (and many would say crappy) wing design. I know nothing about the NGs.

12-31-2002, 06:30 PM

Thanks for the knowledge, Phugoid. The slats were indeed deployed on both the A310 and A300, so you're right on the money. The explanation of the short haul, low altitude tendencies make a lot of sense too. Very interesting.

12-31-2002, 11:25 AM	#1
CAL 757-300 Guest Posts: n/a	Airbus A300/A310 Last weekend I flew on both an A310 and A300-600R (first one ever for me!) and noticed something odd, and at the time a bit unnerving: flaps aren't used for takeoff! Can any of you engineers out there explain how the wing on the A300 generates enough lift for takeoff without the use of flaps? Thanks.

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12-31-2002, 12:58 PM	#2
Phugoid Collector Join Date: Aug 2002 Posts: 90	The A-300 was initially developed as a short range jet, with stage lengths between 1 and 2 hours. The optimum altitude is in the mid twenties and the wing is not designed to be super efficient at high speed and high altitude. Being built for the shorter stage lengths, a high lift, low speed wing was more optimal. Though you do not need flaps for takeoff with the A-300 b2, b4, 600, slats are required. A flaps up takeoff requires greater runway length due to increased Vr speed. A flaps up takeoff also gives a better climb gradient, and generally allows more weight to be carried, as it is not second segment climb restricted. Boeing tends to design wings for high speed flight, with the exception of the 737, the 72 has a crit mach of .90 and the 74 is also around that number, either .9 or .92. When a high speed wing is desirable a decrease in drag is required and lift in the lower speeds is sacrificed. Flaps are installed to relieve this deficiency during the slow speed region of takeoff and approach. As for why a flaps up takeoff cannot be safely accomplished with a 73 original/ classic, is because it has an old (and many would say crappy) wing design. I know nothing about the NGs.

12-31-2002, 06:30 PM	#3
CAL 757-300 Guest Posts: n/a	Thanks for the knowledge, Phugoid. The slats were indeed deployed on both the A310 and A300, so you're right on the money. The explanation of the short haul, low altitude tendencies make a lot of sense too. Very interesting.