in 1961, several aircraft solutions began studying heavy jet transport designs The idea would replace the Douglas C-133 Cargomaster AND complement Lockheed C-141 Starlifters. IN ADDITION TO higher total performance, your own UNITED STATES OF AMERICA Army wanted a transport aircraft using a larger cargo bay as compared to ones C-141, whose interior was too small in order to carry the countless it is outsized equipment. these kinds of accounts led towards the "CX-4" design concept, but within 1962 your proposed six-engine design \'m rejected, because the This \'m not viewed as a crucial advance from the C-141.[3] through late 1963, the next conceptual design was named CX-X. That was equipped within four engines, instead connected with 6-8 engines for the earlier CX-4 concept. your CX-X had a gross Force associated with 550,000 pounds (249,000 kg), the maximum payload involving 180,000 lb (81,600 kg) AND a good speed associated with Mach 0.75 (500 mph or even 805 km/h). ones cargo compartment am 17.2 ft (5.24 m) wide by 13.5 feet (4.11 m) high AS WELL AS 100 ft (30.5 m) very long in front IN ADDITION TO rear entry doors.[3] to be able to meet the power ALONG WITH variety Prerequisites within singular four engines required a fresh engine within dramatically improved fuel efficiency.
"We switched on in order to produce your own C-5 AND wanted in order to develop your current most significant thing we could... Quite frankly, your current C-5 process \'m a great contribution to help commercial aviation. We'll never consider credit pertaining to it, but when i incentivized It industry from developing [the TF39] engine."
General Duane H. Cassidy, former MAC Commander inside Chief[4]
The criteria were finalized ALONG WITH an standard get proposal was granted in April 1964 to its "Heavy Logistics System" (CX-HLS) (previously CX-X). inside can 1964, proposals pertaining to aircraft were bought via Boeing, Douglas, General Dynamics, Lockheed, AND Martin Marietta. General Electric, Curtiss-Wright, ALONG WITH Pratt & Whitney submitted proposals for the engines. right after a good downselect, Boeing, Douglas ALONG WITH Lockheed were released one-year study contracts for the airframe, IN ADDITION TO General Electric AS WELL AS Pratt & Whitney for the engines.[5] many three of a designs shared a number of features. your cockpit \'m placed properly above ones cargo place to be able to provide regarding cargo loading via a nose door. your current Boeing AND ALSO Douglas designs considered the pod with top of any fuselage containing the cockpit, though your own Lockheed design extended the cockpit profile decrease your length of your fuselage, giving That the egg-shaped cross section. all of the designs had swept wings, IN ADDITION TO front IN ADDITION TO rear cargo doors allowing simultaneous loading AND ALSO unloading.[6] Lockheed's design featured a T-tail, while your own designs from Boeing AND ALSO Douglas had conventional tails.[7][8]
The Air Weight considered Boeing's design to help end up being far better when compared with The item associated with Lockheed, but Lockheed's proposal was ones lowest overall cost bid.[9] Lockheed are selected your current winner within September 1965, next awarded the contract throughout December 1965.[7][10] General Electric's TF39 engine feel selected within August 1965 in order to power your own new transport plane.[7] at the time frame GE's engine title \'m revolutionary, Just like all engines beforehand had an bypass ratio regarding less compared to two-to-one, even though your current TF39 promised AS WELL AS would achieve a great ratio associated with eight-to-one, which had Some great benefits of increased engine thrust IN ADDITION TO along fuel consumption.[11][12]
Into production
The 1st C-5A Galaxy (serial amount 66-8303) feel rolled out of a manufacturing plant inside Marietta, Georgia, with a couple of March 1968.[13] from 30 June 1968, flight testing of the C-5A began from the 1st flight, flown coming from Leo Sullivan, through the call Firewood "eight-three-oh-three heavy". Flight tests revealed that the aircraft displayed a great higher drag divergence Mach variety in comparison with predicted from wind tunnel data. your own maximum lift coefficient measured in flight with the flaps deflected 40-degree was higher when compared with predicted (2.60 vs. 2.38), but was straight down when compared with predicted through the flaps deflected 25 degrees (2.31 vs. 2.38) AND ALSO through the flaps retracted (1.45 vs. 1.52).
