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ftaj or Darry 14 General Farrell made a preliminary etatement on future functions of the ocmlttee and pointed out the representation of the XX AP by Col Fisher in lieu of Gen Nora tad* General Arnold and General Groves had oonoluded that for some time into the future, control of the use of this weapon should reside in Aashin^ton rather than be released fully to 2# Results of the past Trinity test were discussed by Drs* Penney and Von Neumann* These, in general, oloeely confirmed expectations. Of the trial sample of aotire material, little remained in the immediate vicinity of the exploeion* From these results, the safety of aircraft on subsequent trials is assured* Dr* Von Newann indicated that in further experiments of this nature additional measurements at some height above the ground were 8* A renouncement was made of the change since last maating in the matter of fusing heights* This was due to further calculations by Dr* Brode. The heights now agreed upon are five settings from 1100 to 2500 ft*, with planned detonations from TOO to 2100 ft* Col* Fisher was assured that this height of detonation was a well "proven" point* a* Col* Tlbbets reviewed the rehearsal program and status of training* > duoed to IB, and eaoh bombardier has had at least 50 individual releases at altitnds, with most having bad 80 to 100* (2) The plan la to roly on the pilot direction indicator for final approach rather than the auto pilet and training has been (8) On radar bombing, each orew had S to 4 missions per week for 6 weeks* This was only at 20,000 ft* altitude however ae equipsmnt was not pressurised* An Island target was used* Col* Tlbbeta is confident that on a recognised target, they oan (4) Cta Tlaual bonblng training, their SO** eirole is within 600 ft. of the target. The aaxlmei vies so far has bean 2700 ft. with □any reasons (different tall, drop tabloa, sto.) for this axoepticnal UNCLASSIFIED(B) Col Tibbets felt that drops within 1000 ft* on visual and 2000 ft* on radar oould be practically oartain-all things being normal* Col* Fisher stated that reliance should not be pladed upon radar alont value of 1st gadget, but Tibbets pointed out that radar ^though not on the actual BEST COPY AVAILABLE
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(S) On load and dlatanoa testa. Col Tlbbeta-stated orewa had taken off at 136,000 Iba. gross load, flcarn 4300 miles with 10,000 lb. bomb load, bos&ed from 32,000 ft. and returned to base with 900 gallons of fuel. This is in exosss of the expected target run and further tests will reduce the loading to reach the S.O.P. of 500 gallons of fuel on return. b. Capt. Parsons reviewed oharaoteristios of the pumpkin and its pro curement status. A total of 19 hare been shipped to ffendoveri sons have already been dropped. Boitlensok is oooling at UoAlester, and the June quota of 30 May possibly drop to 25. Barring unforeseen delays or laok of safety (unit has bean dropped 8 ft. on oonorete) 25-30 pumpkins at base by 16 July seams assured if Victory ship is used. Colonels Fisher and Tibbets agreed that group should easily be operational by that date, and the latter desires not more than 6 praotloe runs per orew and readiness date of 20 August for the real thing. General Farrell indicated this latter date might have to be stepped up. Concluding on pumpkin production, Capt. Parsons felt production should reaoh 75 per month by mid-June, 80 for overseas, 15 for dwestio use. Col. Tibbets stated that in SeptemberOotober he oould use 75. The probability of making overseas shipments at two week intervals to avoid storage aocumulation at Port Chicago was men o. The modi floation of aircraft from aoorw—orlstlon of pumpkin to the L.B. was estimated to require 6 hours. This is mush less thsua the modification to carry H.l. bombs| this wouldaount te practically a major overhaul job of about 3 weeks (Cel. Tibbetts) The Importance of pumpkin production and shipment is therefore emphasised. d. (1) On movement of AAF units. Cel. Tibbets stated ground echelons — were already at destination, oxoept for the Ordnance company duo te arrive 1 July. Cmdr. Ashworth soncurred, with further remark that this unit should be opsratianal 15 July. (t) The technical group of Capt Parsons and Dr. Ramsey has skeleton orewe for all operationa set up to leave with an ETA of 1 Ally. In addition, se that-there will be at least 2 individuals for saoh func tion, a further group is to leave by 1 Ally, BTA 26 Ally. Cta arrival of this latter group L.B. end F.M. oould. both be handled. 1 August is readiness date far first L.B. sad l£ days is estimated assembly time. Deal si on is still in air on method of shlysmnt-assembled dlsaseomblodj Capt. Paroone stated the Vasy would prefer a disaseembied shipment te ovoid "special* handling to attract attention. The L.B. shlfowt and readiness practically depends upon supply of sotive material. Since ether ocapanenta are ab ut reedy now it might be worthwhile te despatch a water shipment whan 80% of active material is ready and send lest 20% by air. (8) Dr. Rauey stressed importanse of Red Ballspeed for shipment of 3rd batch, sines certain components were oadssians fran 2nd bateh. Departure of 3rd batoh now set up for 1 Ally. CLASSIFICATION CANCELLED UNCLASSIFIED PER DOC REVIEW JAN. 1973
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5. a. Normal proeedura on tarf^t dealgnatlon and assignnant to XXI B.C. by XX A? waa explalnad by Col* Flaher* and tha 3 raaarvad targets for the flrat unit of this project were announoed. With current and prospective rate of 20 AF, H.E* bombing, it la expected to complete strategic bombing of Japn by 1 Jan 46 so availability of future targets will be a problem* The XX AF is also entering a program of Tall Boy and Orand Slam H.E. bombs. It is apparent therefore that staging forward or forward displacement of the base may have to be faoed. Capt. Parsons said personnel presently set up oould be divided into two groups* that Iwo was being prepared for emergency un loading and that a standard aseembly building was being designed and prepared so that by June a decision to establish a new base should be followed by b. Dr* 71Ison raised the point that while targets for efficient use 'of weapon might be exhausted* there might be opportunities for effective use. It was agreed that study of fusing points for F.M. should be under taken to adapt it te tactical use, although its use for penetration was unquestionably impracticable* Present designated targets shouldn't take more than 6 or 7, and perhaps less if conservative estimate of power is o. Dr* Stearns presented data on Kyoto, Hiroshima and Niigata and the To11owing conclusions were reachedi (1) not to specify aiming points, this to be left to later determin ation at base when weather conditions are known* (2) to negleot location of industrial areas as pin point target, since on these three targets suoh areas are nail, spread on fringes (S) to endeavor to plaee first gadget in oenter of selected oityi that is, not to allow for later 1 or 2 gadgets for complete destruction* (4) further data on effects of H*B. and pumpkins on buildings is very desirable| these could be olaseifled as Secret and come in through It was urged that reports of XX AF Damage Analysis Oraup (Hr.Brothers) be available -for study of blast offsets so that relative effect of gadget might be more oloeely determined. Dr. Stearns will set up this procedure, sad the letter to be sent to Oeneral LeUay would be made te include a paragraph on tha Pumpkin program, evaluation of damage and aeourity for mala weapon. Dr. Von Neumann gave It aa his opinion that any hills in vicinity of proposed targets were too remote to have waa vary conservative in his opinion and that 3 p.s.l. should bo sufficient for most Japanese buildings, so greater sffsot for L.B. and 6. a* Regarding weather coverage. Col* Fishor was confident everything possible was being fed into weather oenter and Capt* Parsons is to disouss additional submarine participation with Capt. mil (of Adm. Nimits' staff) and Adm. Purnell. On the possibility of returning to base with L.B. incase of bad i£iW£§ agreed comments from hors oould bo advisory only since
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final deoition had to lay with paopla on the spot. Dr. Ramsey disouseed the planned system for testing the gadget in the aircraft and the plan for ramoral of propelling charge from the L.B. in ease of emergency landing. b. Trials on bank and turn capabilities of B-29s had been completed according to Col Tibbets and it was pointed out as incumbent upon Capt. Parsons and Col Tibbets to conclude the procedure for the first mission and brief all participants. The aircraft could not react to the extra* limits heretofore discussed at T. e. Dr. Stearns stated information of abortive sorties had been gathered and would be discussed with Col Tibbets. The data was assembled from experience in training in the U.S. and in overseas units but would not be directly applicable to the present special unit. 7. Nothing was added to the conclusion of the previous meeting that no coordinate mission should bs undertaken. Continual observation of the QB by aeocmpanylng aircraft was stressed and these aircraft oould drop the tech nical instruments under consideration. The necessity to adhere to radio security and other operational procedure in fores in the theater was pointed out. Capt. Parsons discussed the probably sequence of operations for the 8. Oen Farrell adjourned the meeting until further call, possibly after next Trinity test.