Superfortress.

Or the “Superfort”.

That’s what we called them here in the States; nicknames for the Boeing B-29 bomber.

My aunt called them “地獄からのトンボ” or dragonfly from hell.

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Development

The development of the B-29 actually started before WWII began for the US – in 1939.  Perhaps there were some shenanigans back then but Boeing had engineered a pressurized cockpit for their B-17 Flying Fortress (from whence the nickname Superfortress hailed from) for the USAAF.  Conveniently, the USAAF put together in 1939 a call for a new bomber capable of 400 mph while carrying a 20,000 pound payload.  The B-29 was born.

Her development was not smooth.  Indeed, it was the most advanced aircraft design of its time with its pressurized crew compartment and ten remote control dual .50 caliber Browning machine guns.  The second prototype YB-29 crashed into the Frye Packing Plant in Seattle killing her pilot, Eddie Allen, all ten of her crew of engineers as well as 19 workers on the ground.  (In fact, two engineers managed to bail out over Seattle but they were too low for their parachutes to deploy.)  As an indication of things to come, an engine caught fire 20 minutes into the flight causing the horrendous crash.  As the plane was secret, there was a tremendous cover-up as well.

The production of the B-29 was a nightmare.  Due to immensity of the aircraft for its time, there were no manufacturing facilities large enough to house it let alone build it.  Four assembly plants were utilized with Boeing’s Wichita plant eventually becoming the hub.  The plane’s complexity exacerbated the production; over a thousand sub-contractors were involved.  Production changes were so prevalent, numerous and on-going that even when a B-29 had been assembled, it was towed to a holding area in Wichita to have major modifications done post-production.  The freezing weather also made work a nightmare.  Production was so poor that even when about 97 were delivered in 1943, only about 15 were flyable.

Some examples of these major flaws included:

1.  Defective pressure seals around cockpit windows and gunner blisters;
2.  As each plane had about ten miles of wiring and electronics, there were numerous failures;
3.  Wing structure needed post-production modifications;
4.  Cockpit glass were distorted;
5.  The analog computers used for the new “remote control” machine guns were problematic; and,
6.  As as mentioned, the engines overheated to the point of being set on fire during flight.

Because production of the first B-29’s were done “on the run”, the first 100 built were really built by hand by unskilled laborers.  Each one differed from another.  One end result of this production on the run was that there were significant differences in weight between supposedly identical bombers.

Only personal intervention by the great General Hap Arnold improved the production problem… but it took months.

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The first combat deployment of the B-29 occurred from the China-Burma-India theater of war on June 4, 1944.  Ninety-eight B-29s flew to targets in Thailand.  However, the results were dismal (Reports indicate perhaps one bomb hit target. Most bombs landed two kilometers off target.).  As another indicator of things to come, five B-29s were lost during the mission.  They were not lost due to enemy fire; they crashed due to mechanical failure.

Under the command of Curtis “Iron Pants” LeMay, the first bombing mission to Japan occurred on June 15, 1944.  Sixty-eight B-29s took off from bases around Chengdu and bombed a steel plant in Yahata, Japan.  As a first indicator of an ugly pattern, only 47  of the 68 B-29’s reached their target.

As in the XB-29 prototype crash, the engines were the most serious operational defect.  They utilized the 2,200 hp Wright R-3350 Duplex-Cyclone radial engine with 18 cylinders in two rows. One central design defect rested within the top five cylinders of the radial engine.  These radial engines needed massive air flow to cool them off.  Unfortunately, engine shortcomings, i.e., engine failures, led to a number of crashes at take off when the planes were fully loaded with ordnance or at other unfortunate times during their long flights.  Engines needed overhaul or replacement only after about 75 hours of operation to give you an idea of their unreliability.  Bombing missions to Tokyo averaged 15 hours in the air.

Later models – the B-29B or ‘”Silverplate”¹ – would be stripped of all defensive armament except for the tail gun.

Imagine being on the plane during that time flying over thousands of miles of ocean…exponentially worsened if you were under attack.

I wonder what unpleasant thoughts kept gnawing at Capt. Ray Smisek and his crew during one of their missions.

He was flying the Chevy Citation of the skies.

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Ordnance

AN-M69s

In essence, there were many combinations of bombs used in the bombing of Tokyo.  For the purposes of this blog, we will focus on a couple.

The AN-M69 Incendiary Bomb was a cluster-type jellied gasoline (napalm) weapon; the gel would be contained in a cheesecloth sack then enclosed in a metal tube.  The Standard Oil Development Company started work on the weapon two months before Pearl Harbor.  The engineering goal was to develop an incendiary device with as little magnesium as possible due to supply constraints.  The objective of this weapon was to simply burn things (and the enemy) up.  Ironically, German buildings were the initial target but as the war progressed, use against Japanese targets became the focus.

The most common cluster assembly (the M19) held 38 individual AN-M69s, nicknamed “Tokyo Calling Cards” by her crews; the B-29s would release the M19s 5,000 feet above a target. As the M19 canister would break open, the force of the wind would deploy the streamer attached to each AN-M69 stick.  As the individual AN-M69s scattered in the air stream, they would orient themselves to the nose-down position.  The M1 fuse would activate after hitting the ground or target, then would lay there 3 to 5 seconds allowing the stick to lay on its side. After those seconds, the explosive charge would disperse the burning jellied gasoline, clinging to anything it touched.

For a USAAF film taken of its assembly and testing:

Each B-29 could carry 40 M19 canisters in their bomb bays with each canister carrying 38 AN-M69s. Using simple (non-common core) multiplication, that would be 1,520 AN-M69s per each B-29.  A raid could involve hundreds of B-29s.

There were other variations of this concept, such as the M17s.

AN-M41

We have all been camping at one time or another.  When we try to start a campfire “the old way”, the kids would be sent about looking for smaller twigs and branches to be used as kindling.  Larger logs would then be placed upon the then burning kindling.

The AN-M41 was a 20 pound fragmentation bomb, held in clusters.  There is nothing very unique about this weapon.  Upon hitting a target, it’s mission was to simply break things up upon impact.  Smaller pieces would then be easier to burn, much like kindling in concept.

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I would think it would take immense courage to be flying in an aircraft being shot at while carrying these explosives.  In colloquial terms, it took balls.

Lots of it.  You were in a flying gasoline tanker.

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The perilous B-29 missions will be coming next in Part 3.

Hope you’ll stay tuned.

Edit: You can find the other chapters in the links below:

The Firebombing of Tokyo – Part 1

The Firebombing of Tokyo – Part 3

The Firebombing of Tokyo – Part 4

The Firebombing of Tokyo – Epilogue

NOTES:

1 Ironically, the secret codeword Colonel Paul Tibbetts of the Enola Gay was given by General Hap Arnold while assembling his atomic bombing group was “Silverplate”.  If Tibbetts encountered any administrative SNAFU, he could get anything ordered by using the secret codeword.