With the race underway among numerous states to build the Boeing 777X passenger jet and win its high-paying jobs, the aerospace company said Monday it's testing a miniature model of the airplane in a low-speed wind tunnel.

"This is the first major development milestone for the program since we launched the program last month," said Terry Beezhold, vice president and chief project engineer of the 777X program, in a statement. "Wind tunnel testing will validate our performance models and generate a vast amount of data that our engineering teams will use to design the airplane in this phase of development."

Testing started Dec. 5 at QinetiQ's test facility in Farnborough, England. Low-speed tests measure airplane performance with a variety of high-lift surface settings to simulate takeoff and landing conditions.

The low-speed model currently being tested is about 14-feet long with a wing span of nearly 13 feet. The actual plane, when constructed, will have a wing span of 233 feet, five inches, the greatest of any Boeing airplane, with folding wingtips.

In the small model, hundreds of sensors are embedded to measure pressure to determine the in-flight loads as well as provide valuable diagnostics of the aerodynamic performance of a given design, according to Boeing.

Low-speed testing at the U.K. facility will last about five months and will move next year at the Boeing Transonic Wind Tunnel in Seattle to further validate the airplane's high-speed performance projections.

"We are on track to complete our top-level design in 2014 and reach firm configuration in 2015," Beezhold said.

The 777X family includes the 777-8X and the 777-9X, both long-range airplanes with composite wings longer than the current 777.

Boeing hopes to start production of the new aircraft in 2016 with the first delivery in 2020.

But before it can do that, the company must decide where to build the commercial aircraft.

At least a dozen states are vying to construct the new airplane after Boeing sent out request for proposals Nov. 22. The deadline for proposals is Tuesday.

Among the states mentioned as contenders or actively competing for 777X are South Carolina, California, Alabama, Utah, Texas, Missouri, Kansas, North Carolina, Georgia, Pennsylvania, Wisconsin and Washington, where lawmakers last month approved $8.7 billion in tax breaks through 2040 to lure production to the Evergreen State.

Missouri legislators approved $1.7 billion in incentives last week. Wisconsin is submitting a proposal without being asked.

South Carolina received a request for a proposal, but the state Commerce Department doesn't comment on efforts to lure prospective businesses.

Boeing assembles and makes parts for the 787 Dreamliner at it North Charleston campus at Charleston International Airport. The company will close on a land deal Friday for 267 acres along International Boulevard adjacent to its plane-making operation. Boeing has not disclosed its use for the land, which is being bought through an arm of the Commerce Department.

Boeing said in November it would make its site selection for the 777X within three months.

The company launched the 777X program in November with 259 orders and commitments from Emirates, Etihad, Lufthansa and Qatar Airways.

Reach Warren L. Wise at 937-5524 or twitter.com/warrenlancewise.