What was the largest twin-engine aircraft ever built as of the date of its successful maiden flight? There is only ONE correct aircraft answer to this quiz.

1. Builder?

2. Nomenclature?

3. Model name?

4. Month and year of first flight?

5. How many were produced?

6. Bonus for what aircraft was the quiz aircraft's wing based upon?

7 days later

Measured wingspan. This aircraft was so large and heavy for just twin engines that many expected it would be a four-engine aircraft as with similar at the time. One engine per wing; that my final clue. I expect the true answers may surprise!

13 days later

As per my usual wait for 500 or more views with no right answers, here is the rest of the story, as the late radio announcer Paul Harvey used to say. Wow, that sure dates me!

In 1940 with World War II ongoing in Europe, German submarines (U-boats: Unterseeboots in Deutsch) were detected off America's east coast, even though we were not yet at war. The US Navy felt the solution to guarding America's east coast and the Gulf of Mexico shores would be long range giant flying-boat bombers, similar to Boeing's flying Clippers. The Navy ordered 57 flying-boat bombers to be built by Boeing. A new plant was built at Renton, Washington adjacent Lake Washington to build these aircraft. The prototype first flew in July 1942, but the War Department revised their strategy based upon America's Pacific War entry with Japan's 7 December 1941 sneak attack on Pearl Harbor from aircraft carrier-based aircraft. Only one flying-boat XPBB-1 bomber was built by Boeing.

Here are the quiz answers:

1. Builder-Boeing.

2. Nomenclature-Boeing XPBB-1.

3. Model name-SEA RANGER.

4. Month and year of first flight-July 1942.

5. How many produced-One, which inevitably became known as the Lone Ranger.

6. Bonus: The wing was based upon the Boeing B-29 SuperFortress wing and some aerodynamics were from the famous Boeing Model 314 Clippers.

The Renton plant was subsequently used to build over 1,000 B-29s and later C-135 jet tanker/transports and B707 jet airliners.

XPBB-SEA RANGER specs and performance

Powerplant: Two Wright R-3350-8 piston engines of 2,300 Hp each, mounted fairly inboard on the wings which had fixed outer sponsons.

Length: 94'9"

Wingspan: 139'9"

Height: 34'2"

Gross weight: 101,130 lbs

Max speed: 215 mph

Crew: 10

Defensive armament: four machine guns, two in a nose ball turret and two in a dorsal turret.

Bomb Bay load-greater than a B-29's.

The XPBB Sea Ranger was NOT amphibious. Seaplane hull only.

The sole XPBB-1 was initially "mothballed", then scrapped, never to fly a war mission. I have photos of the Sea Ranger in flight and in motion in water, but cannot for others' copyright reasons show them here.

Yes it is, and I thank you for your comment and interest.

I just now today checked Wikipedia to see what they had on the Boeing Sea Ranger. My reference differs some. Wikipedia lists two waist gun turrets and a tail turret also, making 5 gun positions in all. My photos of the flying prototype do NOT show the additional gun turrets, so those may have been planned for production aircraft, which, of course, never happened.

Thank you! The photo of the only Boeing Sea Ranger appears to show a launch via a hull cradle into Lake Washington from Boeing's Renton plant waterfront concrete slab. I had not seen that photo before.

The otherwise definitive Naval Institute Press book "United States Navy Aircraft since 1911" by Gordon Swanborough and Peter M. Bowers published in 1968 gives the Boeing PBB Sea Ranger Patrol Bomber only two lines of short note on p. 536. No photo.

No worries, Doug. Found on Photobucket.com by Google images.

Peter.