Monocleman From United States of America, joined Apr 2001, 137 posts, RR: 0 Posted (13 years 7 months 1 week 5 days 21 hours ago) and read 1030 times:
When looking at the Air Force specs page for the C-5, there are two maximum takeoff weights - 769,000 pounds (peacetime), 840,000 pounds (wartime). Why can more be carried in wartime? Does it involve running engines over n1 or something along those lines or do you just flick a switch to increase preformance?
MikeN From , joined Dec 1969, posts, RR:
Reply 1, posted (13 years 7 months 1 week 5 days 8 hours ago) and read 891 times:
The C-5 is capable of taking off at the wartime max gross weight of 840,000 pounds with no problem (as long as the necessary field length is available). Actually, "I" feel the Galaxy is capable of taking off at over one million pounds gross weight! But, heavier gross weights put a lot of stress on the wings, therefore shortening their lifespan. The 769,000 pound GW limit is in place to ensure the wings aren't unecessarily overstressed. Also, the 769,000 pound limit ensures that the C-5 can takeoff from just about any "improved" airfield in the world. By "improved" I mean it must be made of concrete or something of the sort, otherwise the aircraft could sink at heavy gross weights.
The heaviest GW that I ever took off at was just under 800,000 pounds during the Gulf War. We had two M1-A1 Abrams tanks, 73 PAX, and a lot of fuel on board.
C17load From , joined Dec 1969, posts, RR:
Reply 2, posted (13 years 7 months 1 week 5 days ago) and read 884 times:
Mike hit the nail on the head on this one. The "Peacetime" weight will always be significantly less the the war weight. This ensures that we are not putting too much stress on the wings as well as the engines. As expensive as planes are these days, we have to conserve them as long as we can.