Northrop XB-35 | A Answer to the United States Dilemma

The_Marco_Polo · May 3, 2024, 11:31pm

The Northrop XB-35

The Northrop XB-35, a innovative new idea to design and supply a low drag intercontinental heavy bomber that would be able to punch into German territory in 1941.

More Info

Spoiler

World War 2 and the United States Dilemma

During the first years of world war 2 the United States had run into if problem. Due to the massive attack from Germany in Europe the allies needed support in the war effort from the United States. The United States had some of the best bombers in the world with being heavily armed and would be able to take abuse which made them extremely effective like the Boeing B-17 or the Boeing B-24. But there still a major issue the United States were running into.

Due to the weight, speed and fuel amount of these bombers, they were not able to make it across the Atlantic to make a strike in German territory. So the United States went to its aircraft manufacturing company’s and asked them to develop a new intercontinental bomber.

One of those men to respond was Jack Northrop.

Jack Northrop looked at the other designs of what intercontinental bombers would look like having to be almost 3x - 4x size of the current bombers in service and having to be heavy due to the fuel the aircraft would need to cross the Atlantic which made them much slower due to drag and weight and he thought, what if you only need the wings.

Earlier in Jack Northrop’s career he was greatly interested in flying wings with aircraft such as the Northrop N-1M to develop a aircraft with less drag then normal aircraft.

He drew a radical new design of a aircraft with no fuselage with no tail fins but only the engines and wings. This made the aircraft have significantly have less drag and be able to achieve crossing the Atlantic with a total range of 7,500 miles.

Along with the aircraft having significantly less drag, it was designed with Pratt & Whitney R-4360 Wasp Major engines which at the time were the most powerful engines ever put into production making 3,000 hp. These engines were designed with a counter rotating propellers which greatly increased the speed of the aircraft, it was able to go 391 mph.

The aircraft was designed with 6 underwing bomb bays which made the aircraft able to carry a impressive load of 52,200 lbs. This made the aircraft be able make a heavy punch on enemy targets.

It was also designed with 6 remotely controlled turrets and a stinger turret which gave the aircraft plenty of protection from enemy aircraft. Inside there were even folding bunks for off duty crew members to rest.

On 30 September the USAF ordered 13 pre-production XB-35s 1943 and the first prototype was built in June 1946. It was flown from Hawthorne California to Muroc Dry Lake for more testing.

Due to the newly developed counter rotating propellers being almost never tested it was found to be failing in test flights. Along with the AAF failing to deliver the AC electrical alternator which resulted in Northrop only being able to use auxiliary power unit which limited the aircraft to only fly at 15,000 ft. Later on, Jack Northrop grounded the aircraft. Due to these issue it was later found to be safer to use single rotation propeller but it reduced the speed of the aircraft and increased the length needed for take off.

The beginning of the end

Testing continued into 1947 which left the XB-35 with a major issue. The propeller driven bomber had to go up against aircraft in the start of the jet era and major issues such as overheating or propeller issues that came up during test flights made flights be cut short. The engines that in 1941 were the best aircraft engines ever made were now outdated.

Due to these issues the USAF later ordered the XB-35 be outfitted with 8 jet turbine engines for higher speed which the aircraft would me marked the YB-49.

Due to the YB-49 being a superior and more reliable aircraft, all XB-35s were later torn down and parted out for scrap metal with the first 2 prototypes being scraped on the 19th and 23th of August 1949.

Later on the entire flying wing project were canceled due to high cost of the project and the USAF losing interest, along with the contract being given to Convair for the B-36 that most know of today. And at the time the Boeing B-52 was even on the drawing board.

Armaments

Spoiler

Turrets: 20 × .50 in (12.7 mm) M3 Browning machine guns in six remotely controlled turrets and one tail stinger

Bombs: 52,200 lb (23,678 kg) of bombs, maximum

Characteristics - Performance - Avionics

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Crew: 9: pilot, copilot, bombardier navigator, engineer, radio operator, three gunners
Length: 53 ft 1 in (16.18 m)
Wingspan: 172 ft 0 in (52.43 m)
Height: 20 ft 3.5 in (6.185 m)
Wing area: 4,000 sq ft (370 m2)
Aspect ratio]: 7.4
Airfoil: root: NACA 653-019; tip: NACA 653-018
Empty weight: 91,000 lb (41,277 kg) with turrets
Gross weight: 154,000 lb (69,853 kg) with turrets
Max takeoff weight: 209,000 lb (94,801 kg)
Fuel capacity: 10,000 US gal (8,300 imp gal; 38,000 L) internal; 18,000 US gal (15,000 imp gal; 68,000 L) with bomb-bay auxiliary tanks fitted
Powerplant: 2 × Pratt & Whitney R-4360-45 Wasp Major 28-cylinder air-cooled radial piston engines, 3,000 hp (2,200 kW) each mounted left and right outboard
Powerplant: 2 × Pratt & Whitney R-4360-47 Wasp Major 28-cylinder air-cooled radial piston engines, 3,000 hp (2,200 kW) each mounted left and right inboard
Propellers: 4-bladed Hamilton StandardHSP24F60-344, 15 ft 3 in (4.65 m) diameter constant-speed fully-feathering pusher propellers

Performance

Maximum speed: 391 mph (629 km/h, 340 kn)
Cruise speed: 240 mph (390 km/h, 210 kn)
Range: 7,500 mi (12,100 km, 6,500 nmi)
Service ceiling: 39,700 ft (12,100 m) (restricted to 20,000 ft (6,096 m) due to APU problems)
Rate of climb: 625 ft/min (3.18 m/s)
Wing loading: 45 lb/sq ft (220 kg/m2)
Power/mass: 0.07 hp/lb (0.12 kW/kg)