Boeing XPBB Sea Ranger

https://en.wikipedia.org/wiki/Boeing_XPBB_Sea_Ranger

The Boeing XPBB-1 Sea Ranger (Boeing 344) was a prototype twin-engined flying
boat patrol bomber built for the United States Navy. The order for this aircraft
was canceled, to free production capacity to build the Boeing B-29, and only a
single prototype was completed.

Well before the United States entered World War II, the Navy started a program
to develop a long-range flying boat, able to cover the vast expanse of the
Pacific Ocean. The Model 344 design offered by Boeing was chosen, and a contract
for 57 aircraft was awarded on 29 June 1940. The designation given to the type
was PBB for Patrol Bomber, Boeing, the first aircraft of the PB category built
by Boeing for the Navy. Nevertheless, Boeing did have important experience in
the construction of large flying boats, having produced the successful Boeing
314 airliner. To build the large PBB, Boeing started construction of a new
lakeside factory in Renton, Washington, that was owned by the US Navy. However,
the prototype was constructed mostly in Seattle, and was moved to Renton only
for completion.

To achieve the desired long range, the PBB became a fairly large aircraft, with
a wingspan of 139 feet 8½ inches (42.59 m) and a crew of ten. Despite its size,
it was powered by just two Wright R-3350 Duplex Cyclone radial engines, driving
three-bladed Curtiss Electric propellers. It was the largest twin-engined flying
boat flown during World War II. For a flying boat, the PBB was aerodynamically
clean, with a cantilever wing set high on the fuselage. The planing bottom had a
single step, and the non-retractable outrigger floats were attached to
streamlined, cantilever struts. The lower hull was divided with seven watertight
compartments, and a short upper deck provided seating for the cockpit crew. The
wing of the PBB was constructed in a center section and two outer panels. The
center section carried the engine nacelles and contained the internal bomb bays,
as well as fuel and oil tanks. The outer wing panels contained main and
auxiliary, integral fuel tanks.

The defensive armament of the PBB consisted of five powered turrets, equipped
with Browning .50 M2 machine guns. They were installed in the nose, in the tail,
on the upper fuselage just aft of the trailing edge of the wing, and in two
waist positions at the rear fuselage. Except for the waist guns, the turrets had
two guns each. Offensive armament could consist of up to 20,000 lb of bombs in
internal bomb bays in the wing center section (five bays on each side) or of two
Mk.13 or Mk.15 torpedoes slung under the wing center section.

The 1710 US gallon auxiliary outer and 1565 US gallon inner fuel tanks were
intended to be used only in an overload condition, in which the PBB would use
catapult-assisted takeoff to achieve a theoretical range of 11000 miles (17700
km). The normal range using the main fuel tanks was 4245 miles (6830 km). In
March 1941 the Navy's Bureau of Aeronautics asked the Naval Aircraft Factory for
a catapult able to launch a PBB-1. The NAF duly prepared a design for a Mark VII
catapult that would be able to launch a fifty-ton PBB-1 at a speed of 130 miles
per hour. The catapult would be installed so that the flying boat could be
lifted onto it with a large crane or hydraulic jacks. However, in the summer of
1942, while development of the Mk.VII catapult was still ongoing, the Navy
cancelled the project because it considered JATO assistance at takeoff more
practical.


Role
Prototype patrol bomber

Manufacturer
Boeing

First flight
9 July 1942

Retired
1947

Status
Prototype

Primary user
United States Navy

Number built
1

The prototype, designated XPBB-1, made its first flight on 9 July 1942 from Lake
Washington. The aircraft handled very well and was considered technically
successful. However, already in 1942 the PBB program had been cancelled: The
need for a long-range flying boat had been reduced by the ability of land planes
such as the Consolidated PB4Y to fly long-range missions over the ocean, and
construction of a small number of PBB-1s would have a negative impact on the
production rate of the B-29. The Navy allowed the Army to use the Renton factory
for the production of B-29 bombers, in return for the use of another factory in
Kansas.

The single XPBB-1 was handed over to the US Navy, and was used in trials
programs until 1947, when it was finally retired. Despite suggestions that more
aircraft might be built, perhaps by another factory, it remained the single
example of the type, and was accordingly nicknamed "Lone Ranger".

Specifications (XPBB-1 Sea Ranger)

General characteristics
Crew: 10
Length: 94 ft 9 in (28.89 m)
Wingspan: 139 ft 8½ in (42.59 m)
Height: 34 ft 2 in (10.42 m)
Wing area: 1,826 ft² (169.7 m²)
Empty weight: 41,531 lb (18,878 kg)
Loaded weight: 62,006 lb (28,185 kg)
Max. takeoff weight: 101,130 lb (45,968 kg)
Powerplant: 2 × Wright R-3350-8 radial engines, 2,300 hp (1,716 kW) each

Performance
Maximum speed: 186 knots (214 mph, 345 km/h) at sea level
Range: 6,300 mi (5,500 nm, 10,000 km) (maximum)

Normal range: 3,691 NM, (4,245 mi, 6,834 km)
Service ceiling: 22,400 ft (6,830 m)
Rate of climb: 980 ft/min (4.98 m/s)
Wing loading: 34.0 lb/ft² (166 kg/m²)
Power/mass: 0.15 hp/lb (0.24 kW/kg)

Armament

Guns: 8 × .50 in (12.7 mm) machine guns in bow and tail turrets and waist
positions
Bombs: 20,000 lb (9,100 kg)




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