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USAF’s horror year 1950, loss of 6 aircraft in 7 weeks, incl. a B-36 with a Nuclear bomb!

February 13, 1950. The dramatic story of a Convair B-36 B Peacemaker losing an Atomic Bomb!  USAF’s Strategic Air Command’s long-range Bomber (with tail code  44-92075) en route from Fairbanks, Alaska, on a non-stop 3000-miles flight to Fort Worth, Texas.

It was a test flight in freezing weather  (-40 F/- 40 C) and included a simulated atomic attack on San Francisco, CA. For that purpose, the aircraft carried a nuclear bomb inside (a Mark 4, Fat Man). Most probably due to icing in the carburetor air-intakes of the mighty Pratt & Whitney R-4360 radial engines, the aircraft lost 3 of its 6 piston engines. Something that would happen more often on this aircraft with its odd pusher-engine configuration.

While the plane lost altitude, it was decided to drop the 5 tons atomic bomb before the plane would crash, flying along the Alaskan Coastline into the Canadian Airspace of Northern British Columbia. Detail piquant:  the bomb contained a substantial quantity of natural uranium and over 2 tons of conventional explosives.  The USAF always denied the presence of plutonium, preventing an accidental nuclear blast in case of an emergency.

B-36_Peacemaker 2

photo no. 2

The flight of an early type Consolidated/Convair B-36B Peacemaker seen in photo no. 2, without the 4 Jet-engines that would feature on later models in a set up under the outer wing panels. The Jet-engines were not intended to be active during normal flight conditions,  those gas-guzzlers only went on in case of emergency when confronted with enemy fighters or flying over hostile terrain.

As the plane was doomed with 3 engines out and the 3 others not capable of running on full power, the crew decided to bail out by parachute, rather than land. Flying over Princess Royal Island, they tried to fix a dropping zone over land, but the timing of the first crew-jumps was miscalculated, and 4 of the 17 crew members landed in the sea; they all drowned.

One member never jumped, and 12 others survived, but it took quite some effort to track them in the barren, remote land. And what happened with that lost Nuclear Bomb? According to official sources, it was detonated mid-air after it was dropped from the crippled B-36’s bomb bay.  But some reports stated that the bomb only exploded as it hit the ground somewhere in Northern BC. Evidently, the uranium was never recovered.

But there were more surprises to come. Before the pilot jumped out, the stricken aircraft was set to fly on automatic pilot, hoping to make a final plunge in the deep of the Pacific. Due to that information, there was no further search made for the lost B-36. However, 3 years later, the wreckage of the B-36 was spotted by a Canadian Search plane, rather intact on a location near the remote Nass Basin, NW of Hazelton, BC.

The USAF rushed out to the spot as they surely had a few things to recover from that plane before others could get there. Explosives were used for partial destruction after crucial components were taken out, and the location was kept ‘secret’, while many locals must have known about the site.  New expeditions in 1956 and much later in 1997 were undertaken, followed by small-scale salvage expeditions to retrieve instruments and parts of a gun turret (all on display in the local Bulkley Valley Museum in Smithers. BC).

The site is now declared protected and links with the first-ever loss of an Atomic Bomb during a USAF flight forever. There would follow at least 7 more incidents in which US Nuclear weapons were involved/lost.

 

Consolidated , Convair factory

photo no. 3: The Texas plant of Consolidated/ Convair, in total 385 B-36’s in all variants were built here from 1948 to 1959.

The B-36 was a huge plane with its wingspan of 230 ft  (70 m), big, even by today’s standards.  USAF’s first long-range bomber could deliver a nuclear bomb over almost any place in Russia due to its flight range of 10.000 miles (16.000 km).

Its payload of 33 tons allowed the hauling of the Thermo-nuclear and Atomic bomb with sufficient fuel and oil on board to feed the 6 thirsty piston engines R-4360 on their way to Moscow and back home, and at a flight level of 40.000 ft, well above the Russian detection range of their radar systems.

In an era that the Cold War developed into more hostile confrontations between the Super Powers (from the no bullets-showdown of the Berlin Blockade in 1948 to the Korean War that started in 1950 was a significant escalation of military confrontation in only 2 years).

No Intercontinental Ballistic Missile existed yet that could make an efficient nuclear deterrence, so the B-36 was the only capable delivery platform at that time, which could make some threatening impression on USSR and China. Yet, the arrival of the Russian Mig-15 Jetfighter on the scene in the Korean conflict was a clear sign on the wall: the B-36 was too slow for such an interceptor.

The sluggish bomber would be extremely vulnerable in a nuclear attack-flight over Russia. Its Days of Glory were short-lived. The career of the B-36 was to serve merely as a stop-gap, waiting for the genesis of a true flying Icon of the Cold war, the venerable jet-powered and swept-wing Boeing B-52, operational since 1956 and still in USAF service today! (see the chapter: 5 aircraft flying in the USAF for 50+ years)

 

 

Pratt Whitrney R-4630 radial 28 cyl.piston prop

photo no. 4: The Pratt & Whitney R- 4360 aero engine heralded the final development in big radial piston engines.

The brute Radial engine P & W R-4360 cranked out 3.800 hp in later versions from its 4360 cubic inches  (almost 72 liters of displacement from 28 pistons. With its 4 rows of 7 cylinders stacked around the crankcase, it had the looks of a giant corncob and subsequently got that nickname.

It had double spark plugs in its 28 cylinders, making 56 spark plugs per engine.  The R-36 with six engines had a whopping total of 336 plugs, a day of work for a wrench jock to replace them all!  There was a supercharger mounted  (you can see that one on the opposite side of the Prop shaft), and for more hp-output, there came on top 2 turbochargers.  The huge propeller was linked via a gearbox to the engine to reduce the prop’s revs and avoid the prop tips to reach supersonic speed. Apart from the terrible noise the tips would generate, that condition would be inefficient in propulsion.

As you can see in the photo no. 4, there were a zillion moving parts of pistons, rockers, valves, pushrods,  big ends, gearboxes, etc.  A very complex machine was vulnerable due to the high mechanical and thermal stress on all those components. The Wasp Major was more or less the ultimate radial that also powered contemporary big Prop liners as the Boeing Stratocruiser and its military variants C-97/KC-97

But in those Boeing-made aircraft, the engine was used in the tractor configuration with the propeller in front. With the B-36, however, the reputation of the R-4360 was best described as “temperamental,” but that had a lot to do with the Pusher Prop configuration.

According to my friend Dirk Septer (friend and author of 2 chapters in this book), the carburetor air intakes did not get the warm air first routed and heated by the cylinders (as in normal tractor set up). Therefore they were prone to icing in the cold weather of the Arctic.

The cooling of the cylinders also played up, which could result in overheating and even engine fires.  The capricious multi-row ’round’ piston engine for big aircraft had found its technological limitations; its career came to a close as the Jet engine (and the related Turbo Prop-engine) came available.

The Jet is basically a much simpler design of an engine, with way less moving/reciprocating parts and a big step forward in the power-to-weight ratio. Where the Corncob was running to a power output ceiling of max  4.300 hp (3200 kW) with a weight of 3900 lb (1750 kg), the Jet development so far did not meet any power output limits yet.  In  75+  years of continuous improvement, there is still progress in reliability, thrust, and fuel economy with every new jet -engine design.

Wasp Majors were produced between 1944 and 1955; 18,697 were built. They were destined for the last of the Large displacement “Piston Props.” Its successor in the USAF, the Boeing B-52 with full Jet propulsion, must have been welcomed as a relief in serviceability and reliability.

B-36 peacemaker

photo no. 5:  This picture above shows the giant leap forward made in the mid-1940s in aviation construction technologies. The B-36 dwarfed the Boeing B-29 Superfortress, the Hero of the Pacific War, that brought Japan to its knees in Aug 1945.  Less than 4 years later, the B-36 rolled out of the semi-open-air assembly lines (no hangar was big enough at the time to house the Bomber fully).

With two bomb bays, the plane could carry the largest thermonuclear warheads existing of that time (Mark-17, 19 tons!). There came superlatives for the plane, it was called the “Aluminum Overcast” due to its huge size, but also “SAC’s Long Rifle” (evident with a flight range of 10.000 miles).

But others had less positive nicknames reserved. What about the “Billion Dollar Blunder”? True or not, I saw the B-36 in the National Museum of the USAF in Dayton, OH, where you can walk right under its open bomb bays, and that is an impressive sight for sure. With a length of 50 meters and a wingspan of 70 meters, the monster-machine was flying in the late 1940s, which is worth a compliment as being a technological achievement of exceptional allure, in which lamentation about its costs has no longer any arguments.

The B-36 claimed its place in the History of US Nuclear Deterrence, the first-ever aircraft that could deliver the atomic bomb over 10.000 miles, right into Russia. Fortunately, that capacity of the B-36 was never deployed, most likely thanks to its sheer existence, a real Peacemaker!

In my next week’s post, I’ll describe the loss of another USAF plane, a C-54 (Military version of the DC-4), also in Jan. 1950 over Alaska/ Canada, a mystery that is unsolved until today. With 44 people on board, a huge search action was undertaken, and two planes that took part in this search went down in the Yukon Mountains. One of them you can see below, with the Dakota Hunter standing next to the almost intact fuselage of the  C-47, peacefully stretched over the mountain slope and surrounded by huge boulders.

 

Dakota Yukon crashsite low res

photo no. 6

The USAF C-47 depicted in photo no. 6 went down in the Yukon mountains, North of Haines Junction, in Jan 1950. Its aluminum skin is in a shiny as-new state, apart from the runaway prop’s damages from the starboard engine that almost killed the radio operator.

Read all details of how the 10-men crew survived the luckiest crash-landing and see more stunning photos of this crash site in my book “The Dakota Hunter”.

www.dc3dakotahunter.com.

 

 

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