The Historic Timelines

Timeline #1 - The 509th; From Inception to Hiroshima

Spring 1943 - Tibbets returns to the U.S. to participate in the B-29 program.

Summer 1943 - Tibbets reports to Wichita, Kansas for B-29 program.

Summer 1943 - Training assigned to Smokey Hill Airfield near Salina, Kansas.

Summer 1943 - Tibbets reassigned to Grand Island, Nebraska to start a training school for B-29 pilots.

Summer 1943 - Tibbets goes to Alamagordo, NM to work with E. J. Workman, a UNM physics professor to study the vulnerability of the B-29 to attack.

Summer 1943 - Tibbets flies a "stripped" bomber for the first time during testing, and found that it handled better than a fully equipped plane.

Fall 1943 - Army Air Force decides to use B-29 to deliver the atomic bomb.

2/28/44 - 393rd Bombardment Squadron created.

3/11/44 - 393rd activated as part of the 504th Bombardment Group.

4/27/44 - Lt. Col. Thomas Classen chosen as commander of the 393rd.

4/27/44 - General "Hap" Arnold hand picks Tibbets to command the new project.

9/1/44 to 9/5/44 - Tibbets flies B-29 to Colorado Springs in response to a call from General Uzal G. Ent, Commander of the 2nd Air Force.  Introduced to Navy Capt. William Parsons and Norman Ramsey, Ph.d., a professor at Columbia University.  Is asked to organize a combat force to deliver a new type of explosive device that is so powerful, its full potential is unknown.  Ramsey then explained the secret of the new bomb.  Tibbets is asked to devise a way to increase the distance between the bomber and the blast of at least 8 miles.  The bomb bay would have to be modified.  15 B-29's and approximately 1,800 people will be assigned to the new group.  Tibbets and Albury fly to Wendover Field in Utah (formerly a P-47 training base) and choose it as their training base.  General Ent offers Tibbets the 393rd Bombardment Squadron as the nucleus of the new outfit.  Tibbets becomes commander of the 393rd, and Lt. Col. Tom Classen becomes Tibbets' deputy commander.

9/8/44 - Tibbets sets up headquarters at Wendover Field.

9/11/44 - 393rd personnel arrive, including 15 B-29's with flight and ground crews.  In addition, Tibbets personally chose the following:  Tom Ferebee - Bombardier; George Carron - Tail Gunner; Dutch Van Kirk - Navigator; Wyatt Duzenbury - Flight Engineer; Bob Lewis - Pilot; Charles Albury - Pilot; Charles Sweeney - Pilot; James Van Pelt - Navigator; Kermit Beahan - Bombardier; and Jacob Beser - Radar Specialist.

11/25/44 - 393rd reassigned from 504th Bombardment Group to the Second Air Force.

12/9/44 - 509th Composite Group was constituted.

12/17/44 - 509th CG officially activated, and became the new higher headquarters for the 393rd Bombardment Squadron.

Early 1945 - Original 393rd B-29's replaced with new ones direct from the assembly lines, modified to Tibbets' specifications.  

3/6/45 - 1st Ordinance Squadron (assigned to arm the bombs) joins the 509th.

5/6/45 - 1200 support personnel of the 509th sail to Tinian aboard the troopship SS Cape Victory from Seattle, WA.

5/18/45 - Advanced air eschelon arrived on Tinian,

6/11/45 - B-29's began arriving on Tinian.  Upon their arrival, the 509th became a part of the 313th Bomber Wing of the Twentieth Air Force.  The 509th remained in relative isolation on the island, near North Field.

7/20/45 - 509th flew its first mission over Japan, followed by more missions on the 24th, 26th and 29th using groups of 2 to 6 planes, practicing precision bombing rather than area bombing.

7/25/45 - The War Dept. issued orders to General Spaatz, Commanding General of the US Army Strategic Air Forces, readying the 509th for action. ("click" here to view the actual "directive")

7/26/45 - The USS Indianapolis dropped anchor off Tinian and unloaded a 15 foot wood crate which contained the firing mechanism for the "Little Boy" bomb.  A bucket which contained the first slug of uranium 235 was also on board.  Each was brought to the bomb assembly hut. (The second piece of uranium was carried from Oak Ridge to Tinian by Lt. Del Genio aboard a B-29) (2 other B-29's carried two more pieces for the "Fat Man" plutonium bomb.

7/29/45 - General Spaatz arrived on Guam and brought an order from General Groves authorizing the dropping of the first SPECIAL BOMB on one of four targets, Hiroshima, Kokura, Niigata, or Nagasaki sometime after August 3rd.

8/3/45 - General Groves sent "Special Bombing Mission #13" designating Hiroshima as the target.  The secondary target is Kokura. (The 12 previous missions were "pumpkin" missions)

Other Notable Facts:

• It was determined as being unsafe to drop the atomic bomb from an altitude of less than 30,000 feet.

• The mission to Japan and back to Tinian would take about 14 hours.

• It would take a B-29 two minutes to fly 8 miles.

• It takes the bomb 43 seconds to drop from 31,000 feet to the point of detonation at about 2,000 feet.

• The shock wave will travel at 1,100 ft./sec.; 40 sec. to travel 8 miles.

• B-29 would be 6 miles away vertically when the bomb detonated.

• The most effective maneuver for increasing the distance would be to make a sharp 155 degree turn after releasing the bomb.

• Practice missions involved dropping bombs from 30,000 feet at a target 400 feet in diameter.

• Initially practiced with conventional 2,000 lb. bombs.

• Soon employed "Pumpkins" which were the same size and weight as the SPECIAL BOMB.

• Originally practiced from Batista Field in Havana, Cuba.

• 5 planes were sent out at a time on 10 day training missions over the Carribean.

• Sweeney frequently accompanied Tibbets as co-pilot on their many trips to Los Alamos meetings, flying into Kirtland AFB at Albuquerque.

• "The Green Hornet Line" was the name used when shuttling scientists and other personnel back and forth from Wendover to Los Alamos.

• When the 509th was first organized, it was assumed that the outfit would be divided, with one unit going to Europe and the other to the Pacific.

• Tinian is an island in the Marianna's Chain which includes Guam and Saipan.

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