SEATTLE, Sept. 18 (Reuters) – It's crunch time for Boeing Co.

After an embarrassing string of delays, the aerospace giant is racing to meet a self-imposed deadline to fly its vaunted new 787 Dreamliner by year's end.

At the center of the storm, Boeing's best and brightest minds, including the newly appointed head of its commercial airplane unit, are scrambling to ensure a smooth takeoff for the company's highest-profile project. With 850 orders for the new aircraft already on the books, the financial stakes for Chicago-based Boeing are enormous.

The company's engineering reputation is riding on the 787's innovative design, which uses lighter materials and promises customers huge savings in fuel and maintenance costs. Boeing is also being judged on its manufacturing strategy which incorporates an unprecedented number of outside contractors.

''In so many ways, it really is a revolutionary leap in technology for commercial airliners, and I think it's going to change the way that airliners are built in the future,'' Dennis O'Donoghue, Boeing vice president in charge of flight testing, told Reuters during a tour of Boeing facilities last week.

But before the revolution can occur, the plane has to fly.

Jim Albaugh, the executive newly assigned to lead Boeing Commercial Airplanes, must exert all the influence he can over the process to ensure Boeing fulfills its commitment to the 56 customers who have placed orders for the aircraft.

The three aircraft in the 787 family, which has been in development since the early part of this decade, have list prices of $150 million to $205.5 million.

In late June, the No. 2 plane maker behind EADS unit Airbus delayed the first flight of the Dreamliner. It was the latest in a series of delays that have put the test two years behind its original schedule.

Boeing blamed a structural problem that required reinforcing an area within the side-of-body joint of the aircraft, which is the connection of the wing to the fuselage.

The company now aims to fly the plane in the fourth quarter.

Despite criticism from aviation experts and frustrated customers, Boeing has said the lightweight, carbon-composite aircraft will be worth the wait.

''As hard as it is, it's worth going after,'' O'Donoghue said. ''When you're the first one out to do something like this, you take your lumps,'' he added.

''We had the structural issue, but they're addressing it,'' he said. ''They'll fix it. I don't foresee that there's going to be any more hiccups.''

Inside Boeing's gigantic assembly complex in Everett, Washington, about 30 miles north of Seattle, gleams a line of 787s coated with a green anticorrosive agent awaiting the side-of-body joint repair intended to pave the way for a test flight.