Washington (AFP) - The US Air Force on Friday unveiled the first image of its next-generation bomber that will replace antique B-52s first developed during the Cold War.

The all-black plane has a distinctive, zigzagging shape and a super-low profile that will make it hard to spot on radar, and bears more than a passing resemblance to the Air Force's B-2 bomber, which is also made by Northrop Grumman.

The new stealth bomber has yet to be built, so Air Force Secretary Deborah Lee James displayed an artist's rendering at an Orlando event.

She said the plane, previously known as the Long Range Strike Bomber, would be called the B-21 until a new name has been agreed on, and she invited air crews to help.

"This aircraft represents the future for our Airmen, and (their) voice is important to this process," James told the Air Force Association's Air Warfare Symposium.

"The Airman who submits the selected name will help me announce it at the (Air Force Association) conference this fall."

The Pentagon in October announced Northrop as the winner of the contract to build the bomber in a decades-long program that will likely end up costing in excess of $100 billion.

The Air Force wants 100 of the warplanes, which will replace the ageing B-52s and the B-1 bombers that first saw action in the 1980s.