The Northrop YB-49, a desperate attempt to keep the flying wing heavy bomber program alive
More Info
Spoiler
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.
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 Allison J35-A-15 turbojet engines for higher speed which the aircraft would me marked the YB-49. This is when the YB-49 comes into the picture.
The YB-49 variant
The YB-49 was a drastic change on what the XB-35 was. Its jet turbine engines were much cheaper and would take less maintenance then the piston engines of the XB-35. The turbine engines would also give the aircraft a much higher speed of the XB-35 making it be able to go 493 mph, almost 100 mph more then the older piston engines.
A addition to its speed, the aircraft went under testing for its radar signature and it was much less then most aircraft due to its wing design which this can also be connected to the B-2 stealth bomber project many years after this project.
Even for all the upsides of having turbine engines on the flying wing airframe, there was many downsides to the aircraft.
The remote controlled turrets on the wings had to be removed due to the higher speeds which removed a lot of protection for the aircraft. The stinger guns were also removed but were planned to be added back after testing the prototypes. Even after removing these things, the airframe was still not able to keep up with the speeds of modern jets of the era even after removing the turrets.
Two bomb bays were removed to help the aircraft carry more fuel but even then, the turbine engines used so much fuel that the range was almost cut in half due to the engines going from 7,500 miles to 3,280 miles. This prevented the bomber from being able to achieve its main purpose to be a intercontinental heavy bomber.
Even with all the ups and downs of the aircraft, the first two YB-49s were delivered to the USAF in 1948 and testing of the aircraft began.
On June 5th 1948 the USAF took the YB-49 on a routine test flight when a situation arose. Staff on the ground witnessed the aircraft moving side to side and in the matter of minutes, the YB-49 broke apart into pieces in flight killing all 5 crew members onboard. Northrop blamed the crew for pushing the aircraft to much but it was later found that the aircraft had issues staying straight which made it impossible for it to bomb at high altitude. Even after the crash the USAF continued testing with the last YB-49 for two more years.
On March 15th 1950 the USAF began testing the YB-49 on high speed taxi runs and in mid run, the nose wheel collapsed destroying the YB-49 causing damages costing a large amount of money.
At this point the USAF had almost lost all interest in the flying wing due to B-36 filling the role that the XB-35 was promised to fill and the B-47 outperforming the YB-49 it most test. Adding onto this all the heavy bombers in use were also able to carry nuclear weapons which both flying wings were not able to.
On a last attempt to keep the program alive, Northrop designed a reconnaissance aircraft based on the YB-49 airframe being marked the YRB-49 but even with this, the YRB-49 was outclassed with aircraft already in use.
Shortly after this the entire flying wing project was canceled and all flying wings on the project were scraped. marking the end of the XB-35, YB-49 and the YRB-49.
Armaments
Spoiler
-
Guns: 4 × .50 in (12.7 mm) machine gun to be mounted in rotating “stinger” tail cone on all production aircraft
-
Bombs: 16,000 lb (7,260 kg) of ordnance
Characteristics - Performance - Avionics
Spoiler
-
Crew: 6
-
Length: 53 ft 1 in (16.18 m)
-
Wingspan: 172 ft 0 in (52.43 m)
-
Height: 15 ft 2 in (4.62 m)
-
Wing area: 4,000 sq ft (370 m2)
-
Aspect ratio: 7.2
-
Airfoil: root: [NACA 653-019]; tip: [NACA 653-018]
-
Empty weight: 88,442 lb (40,117 kg)
-
Gross weight: 133,569 lb (60,586 kg)
-
Max takeoff weight: 193,938 lb (87,969 kg)
-
Powerplant: 8 × Allison J35-A-15 turbojet engines, 4,000 lbf (18 kN) thrust each
Performance
-
Maximum speed: 493 mph (793 km/h, 428 kn)
-
Cruise speed: 365 mph (587 km/h, 317 kn)
-
Combat range: 4,000 mi (6,400 km, 3,500 nmi) Other sources say 2,806 with 10,000 lb (4,536 kg) bombload, 365 Knots in 8:27 hours with 10,000 lbs of bombs.
-
Service ceiling: 45,700 ft (13,900 m)
-
Rate of climb: 3,785 ft/min (19.23 m/s)
-
Wing loading: 33 lb/sq ft (160 kg/m2)
-
Thrust/weight: 0.23
-
Take-off run: 4850 ft
-
Take-off distance to 50 ft (15 m): 5850 ft
Photos
Sources
Spoiler
https://www.warhistoryonline.com/aircraft/northrop-yb-49.html
Northrop's Radical Flying Wing Bomber of the 1940s
- Yes
- No
- Tech Tree Vehicle
- Event Vehicle
- Premium Vehicle
- Squadron Vehicle
- No
- 4.0 - 4.7
- 5.0 - 5.7
- 6.0 - 6.7
- 7.0 - 7.7
- 8.0 - 8.7
- 9.0 - 9.7
- No
