91st Bombardment Group The 91st Bomb Group ( Heavy ) was an air combat unit of the United States Army Air Forces during the Second World War . Classified as a heavy bombardment group , the 91st operated B - 17 Flying Fortress aircraft and was known unofficially as " The Ragged Irregulars " or as " Wray ' s Ragged Irregulars " , after the commander who took the group to England . During its service in World War II the unit consisted of the 322nd , 323rd , 324th , and 401st Bomb Squadrons . The 91st Bomb Group is most noted as the unit in which the bomber " Memphis Belle " flew , and for having suffered the greatest number of losses of any heavy bomb group in World War II . The 91st Bomb Group conducted 340 bombing missions with the Eighth Air Force over Europe , operating out of RAF Bassingbourn . Inactivated at the end of the war , the group was brought back in 1947 as a reconnaissance group of the United States Air Force , and then had its lineage and honors bestowed on like - numbered wings of the Strategic Air Command and the Air Force Space Command . From 1 July 1947 , until its drawdown in February 1952 , the 91st Strategic Reconnaissance Group provided worldwide surveillance , flying RB - 29s , RB - 45s and RB - 47s as a subordinate component of the 91st Strategic Reconnaissance Wing , consisting of the 322nd , 323rd , and 324th Straetgic Recon Squadrons , and the 91st Air Refueling Squadron ( Medium ) . The group was inactivated on 28 May 1952 , as part of an SAC - wide termination of groups as an organizational echelon , while the wing and all subordinate units remained active until 8 November 1957 . The group was activated in 1991 as the 91st Operations Group . Between 1991 and 1994 , and since 1996 , the 91st Operations Group , as part of the 91st Space Wing , maintains the alert force of Minuteman III intercontinental ballistic missile s maintained at Minot Air Force Base , North Dakota . Its three missile squadrons , however , have no traditional link to the 91st Bomb Group and were previously part of the 455th Strategic Missile Wing and 455th Bomb Group . Organization of the 91st Bomb Group ( H ) . The 91st Bomb Group , ( Heavy ) was activated on 14 April 1942 , by General Order 31 of the Third Air Force . Wartime command staff . ¹ Squadron commanders . Four heavy bomb squadron s were constituted 16 May 1942 , and assigned to the group . ¹ Training history and movement overseas . Established 28 January 1942 , and activated on 14 April 1942 at Harding A . A . B . , Louisiana , the 91st Bomb Group consisted of a small administrative cadre without subordinate units until 13 May 1942 , when it was moved to MacDill A . A . B . , Florida . There Lt . Col . Stanley T . Wray took command of the group , and the four flying squadrons assigned to the group were activated . The 91st received air crews and began phase one training with just three B - 17 ' s available . On 26 June 1942 , the group ( now consisting of 83 officers and 78 enlisted men ) was transferred to the Second Air Force and moved to Walla Walla A . A . B . , Washington to complete phase two training , with two squadrons operating from satellite fields at Pendleton and Baker Army Air Bases , Oregon . The 91st received orders to deploy overseas and on 24 August 1942 , the ground echelon entrained for Fort Dix , New Jersey , where it remained until 5 September , embarking on the RMS Queen Mary . Arriving at Greenock , Scotland , on 11 September , the ground echelon moved by train to Kimbolton , a war expansion airfield in the English Midlands . Part of the air echelon moved on 24 August 1942 , to Gowan A . A . B . , Idaho , where it received six new B - 17 F aircraft . From there it flew by pairs , making frequent stops , to Dow A . A . B . , Maine . The remainder of the air crews relocated to Dow by train , arriving 1 September . Between 4 and 24 September the group flew training missions while it received 29 additional B - 17 ' s from air depots in Middletown , Pennsylvania ; Cheyenne , Wyoming ; Tulsa , Oklahoma ; and Denver , Colorado , and conducted phase three training . The 91st Bomb Group moved by squadrons to the United Kingdom , beginning with the 324th Bomb Squadron on 25 September , flying to Gander , Newfoundland . The 324th made a non - stop flight along the North Ferry Route on 30 September , landing at Prestwick , Scotland . The 322d Bomb Squadron moved to Gander on 30 September , and Prestwick on 1 October , followed by one day by the 401st Bomb Squadron . The group lost one of its 35 bombers during transit when a 401st B - 17 crashed in fog into a hillside near Cushendall , Northern Ireland , killing 8 of the crew and a flight surgeon . The 324th Bomb Squadron flew as a unit from Prestwick to Kimbolton on 1 October , followed by the 322nd on 2 October and the 401st on 6 October . On 10 October , the remaining squadron , the 323rd , flew to Gander from Dow . It did not reach Prestwick until 14 October , by which time the 91st had changed bases . VIII Bomber Command had assigned the 91st to Kimbolton intending it to be its operational base . The installation was of war - time construction and had not yet been reconstructed to Class A airfield specifications . Intended as a light or medium bomber field , its runways were not suitable for the combat weights of B - 17s fully loaded with bombs and fuel . Three practice missions in as many days indicated to the staff of the 91st that the runway would quickly deteriorate and Colonel Wray immediately consulted Col . Newton Longfellow , VIII BC commander , who suggested Wray inspect the RAF Bomber Command OTU base at RAF Bassingbourn , Cambridgeshire ( ) , to see if it might be suitable . Wray traveled to Bassingbourn , located four miles ( 6 km ) north of Royston . Not only was the base more appealing from its closer proximity to London , but it had been constructed in 1938 and was considerably more comfortable , with permanent brick buildings , including barracks for enlisted personnel ( in contrast to the Nissen hut s at Kimbolton ) , landscaped grounds with curbed roadways ( Kimbolton , like many war - time fields , was noted for muddy conditions ) ; and had already been re - constructed to a Class A airfield . Wray contacted his staff and ordered them to prepare for immediate relocation . On 14 October , without prior approval , the 91st moved itself and all of its equipment to Bassingbourn in one day and took possession of the station . Combat operations and tactics . The combat history of the 91st Bomb Group can be ordered into three phases . The first , from 4 November 1942 to 1 May 1943 , saw the 91st develop operational experience as one of the four " pioneer " B - 17 groups , creating doctrine and tactics . The second , from 1 May 1943 to 1 January 1944 , had the 91st in a leadership role of the Eighth Air Force at a time when the expanding Bomber Command struggled to establish air superiority without adequate fighter support . The final phase , from 1 January 1944 to 27 May 1945 , was as one part of a massive , systematic campaign supported by a large force of escort fighters that brought to fruition the strategic bombing concept . First phase of operations . The 91st Bomb Group began combat operations on 4 November 1942 , when it received a field order for a mission to bomb the submarine pens at Brest , France , later changed to an attack on the Luftwaffe airfield at Abbeville . Thirty minutes before takeoff the mission was cancelled ( " scrubbed " in the parlance of that time ) because of poor weather . These circumstances were typical of those encountered daily by all the heavy bomber groups in the autumn of 1942 as they pioneered the concept of strategic bombing by daylight . On 4 November the Eighth Air Force consisted of just nine groups . Four ( 91st , 97th , 301st and 303d ) had been earmarked for the Twelfth Air Force in support of Operation Torch and were in England to acquire combat experience and stage for forward movement to North Africa . Two ( 97th and 301st ) had already been withdrawn from operations to prepare for imminent transfer to Algeria and another ( 92nd ) to act as an operational training unit ( OTU ) for replacement combat crews . Of the six remaining units only the 93rd Bomb Group ( a B - 24 unit ) and the 306th Bomb Group were operational , and the 306th had flown only two missions . As late as 15 December the impending transfer of the 91st BG to Algeria was postponed because of logistics difficulties and a shortage of airdromes in North Africa . The group ' s first mission was to Brest , France , on 7 November . The target was the Kriegsmarine submarine base , and was the first of 28 missions against the U - boat force in the following eight months . In all , eight missions were flown in November 1942 , seven of them against the sub pens . The last of these , on 23 November , resulted in the disastrous loss of two squadron commanders , the group navigator , the group bombardier , and three of the five airplanes attacking . In December 1942 VIII Bomber Command issued two - letter squadron identification codes to be painted on the fuselages of the bombers : The 91st was made a part of the 101st Provisional Bomb Wing on 3 January 1943 . Its first mission to a target in Germany occurred 27 January , and it earned the first of two Distinguished Unit Citation s on 4 March when it continued an attack against the marshalling yard s at Hamm , Germany , after all the other groups had turned back because of poor weather conditions . On 17 April the group led the Eighth Air Force on its first mission against the German aircraft industry , attacking Bremen . German fighter reaction was intense and sustained , and the Eighth lost twice as many bombers as on any previous mission . The 91st had six B - 17s shot down , all from the 401st Bomb Squadron . During this phase the group received a substantial number of aircraft to replace those lost of written off . However replacements for lost crewmen were few and made by transfer of individuals . The influx of replacement crews from the Combat Crew Replacement Center at Bovingdon did not begin commence until March 1943 when the personnel requirements of Operation Torch were largely fulfilled . As the 91st developed combat experience , it experienced a decrease in aircraft commanders , apart from missing aircraft and wounds , from moving pilots into command and staff positions . Without an adequate pool of replacements , many co - pilots were upgraded to aircraft commanders . Second phase of operations . The second phase of combat operations , coinciding with the implementation of the Pointblank Directive to target German airpower , began in May 1943 . The Eighth developed in the next three months into a force of sixteen B - 17 groups and began attacking industrial targets deep inside Germany beginning at the end of July . Col . Wray left the 91st on 22 May to become commander of a new wing , the 103rd Provisional Combat Bomb Wing . He was replaced by the group deputy commander , Lt . Col . William Reid , formerly of the 92nd Bomb Group . Lt . Col . Baskin Lawrence , who had been the deputy commander of the 91st from its date of activation , had left the group 1 May to command the 92nd . On 25 June 1943 , a wholesale shifting of command officers between the two groups occurred . Col . Lawrence departed the 92nd to become commander of a new " Pathfinder " group drawn from a squadron of the 92nd , and was replaced by Col . Reid , who left the 91st to command his old group . The 91st received its third commander , Lt . Col . Clemens Wurzbach , who had been Lawrence ' s deputy commander . During this transition period the 91st also had its first crews finish their required combat tours and return to the United States , including the crew of the " Memphis Belle " . Of the original roster of combat crews , 32 % completed their tours , 15 % were reassigned to other commands , and the rest became casualties . At the end of June it also acquired its most recognizable symbol , the " Triangle A " group tail marking often used in films about B - 17s . On 17 August 1943 , the 91st Bomb Group led a mission to bomb the ball - bearing factories at Schweinfurt , Germany , losing 10 aircraft . This was the first of several missions between then and 14 October 1943 , in which the Eighth Air Force , flying beyond the range of its fighter escorts , suffered severe losses of aircraft and crews . The 91st had 28 aircraft shot down during this period , the most of any group in the Eighth . The remainder of the second phase of operations saw a suspension of deep penetration missions until long - range escort fighters became available . Until 22 September 1943 , the 91st BG had been equipped entirely with B - 17F aircraft that had not been modified for longer - range Tokyo tanks . On that date it received is first B - 17G , which would become the standard bomber of the Eighth Air Force in 1944 – 1945 . It continued to receive B - 17F replacement aircraft , along with the B - 17G ' s , until 24 December 1943 . Col . Wurzbach completed his tour of duty on 12 December 1943 , and was replaced by Col . Claude E . Putnam , a former commander of the 324th Bomb Squadron , who returned to his old group from duty as the commander of the 306th Bomb Group , where he had been pilot of the lead aircraft on the first mission to Germany nearly a year before . Wurzbach had commanded the group for 44 missions ; Putnam would command it for 63 . Final phase of operations . The 91st Bomb Group won its second DUC as part of the six - group task force attacking the Focke Wulf assembly factory at Oschersleben , Germany , on 11 January 1944 . This attack marked the renewal of the heavy bomber offensive against targets in all areas of the German Reich . Although losses were heavy ( 34 from the Oschersleben task force and 60 overall ) , three targets were struck by over 600 bombers and a group of P - 51 Mustang s was part of the escort force . From 20 to 25 February 1944 , known as " Big Week " , the United States Strategic Air Forces conducted Operation Argument , a campaign against the German aircraft industry with the goal of achieving air superiority over Europe by drawing the German fighter force into combat . 800 to 1000 bombers , escorted by 700 to 900 fighters , struck multiple targets daily from both England and Italy . The 91st flew all five days , losing ten aircraft , and on 24 February attacked Schweinfurt for the third time . The first attack by the 91st on Berlin came on 6 March , when it led the entire Eighth Air Force at a loss of 69 bombers ( 6 of them from the 91st ) , followed by half a dozen more to the German capital in the next two months . On 12 May the Eighth Air Force began a costly campaign against oil and synthetic oil production facilities that continued to the end of the war . On 17 May , Col . Putnam completed his tour as commanding officer of the 91st Bomb Group and Col . Henry W . Terry took command , which he would retain for 185 missions to the end of hostilities in Europe . Aided by the use of radar - equipped Pathfinder force bombers , the 91st BG averaged a mission every other day for the remainder of the war . In addition to bombing strategic targets , often at great loss in aircraft and crews , the 91st also made tactical strikes in support of the Allied landings in France , in the battles for Caen and Saint - Lô , during the German winter counteroffensive , and during the Allied offensive across the Rhine River . Beginning 16 March 1944 , the 91st began receiving replacement B - 17 ' s that were by a change in USAAF policy no longer painted olive drab , and the bomber force became almost completely " natural metal finish " by July 1944 . The 1st Combat Bomb Wing , of which the 91st was a part , adopted the use of a red empennage and wingtips in June 1944 to more easily identify its groups during assembly for missions . The 91st retained its " Triangle A " tail marking as well . The intensity of operations during this phase is reflected by the 100 B - 17 ' s lost by the 91st Bomb Group during 1944 , compared to 84 in 1943 , despite the diminution of the Luftwaffe during the spring and summer . Radar - directed flak became very proficient in defending critical targets and the fighter force hoarded its pilots and fuel for occasional mass interceptions of the bombers . The 91st BG experienced its worst loss of the war during this period on 2 November 1944 , when it attacked the I . G . Farbenindustrie A . G . synthetic oil plant at Leuna , southeast of Merseburg , Germany . Suffering several losses to intense flak , for which this target was notorious , the 91st found itself isolated from the bomber stream at the division rally point , where it was attacked by large numbers of Fw 190A - R8 " sturm " fighters of IV . / JG 3 . In all , thirteen B - 17s of the 91st were shot down out of 37 dispatched and half of the remainder suffered major battle damage . 49 of the 117 crewmen aboard the Fortresses were killed and the remainder captured . The 91st Bomb Group experienced its final aircraft loss on 17 April 1945 , and flew its last mission , to Pilsen , Czechoslovakia , on 25 April . The 91st had been alerted for 500 combat missions , of which 160 were scrubbed or recalled and 340 completed . Immediately after VE Day , it flew three days of operations to rescue Allied POW s incarcerated at Stalag Luft I in Barth , Germany , as part of Operation Revival , bringing out 2 , 032 prisoners . Casualties . The 91st Bomb Group had at least 392 B - 17 ' s assigned to it at some point of the war . Of these , 40 were transferred to other commands , 37 were retired as unsuitable for further operations , and 71 were on hand at the end of hostilities . The rest were lost : 197 in combat , 37 written off , and 10 in training crashes . Of the combat losses , the 401st and 323rd Squadrons each lost 55 , the 322nd Squadron lost 49 , and the 324th Squadron 38 . Approximately 5 , 200 crewmen flew combat missions for the 91st from 1942 to 1945 . 19 % were killed or missing ( 887 KIA and 123 MIA ) and 18 % ( 959 ) became prisoners of war . 33 others were killed in flying accidents . Of the 35 original crews to arrive at Bassingbourn , 17 were lost in combat ( 47 % ) . Daily records indicate that for the first six months of operations , 22 of 46 listed crews were lost ( 48 % ) . The fatalities in the 91st Bomb Group , equivalent to an infantry regiment in numbers of combat personnel , exceeded the killed - in - action of more than half ( 47 ) of the Army ' s ground force divisions , and equalled or exceeded the rate of killed - in - action in the infantry regiments of 35 others . Only seven divisions ( all infantry ) had killed - in - action rates higher than the 91st BG . Post - war and USAF history . The air echelon left Bassingbourn on 27 May 1945 , and moved to Drew AAB , Tampa , Florida . The ground echelon sailed on the " RMS Queen Elizabeth " to New York on 24 June . The group reunited on 2 July , to prepare for transfer to the Pacific Theater , but many members had been transferred to other units and no further training was conducted before the war ended . The group was inactivated on 7 November 1945 . Following the war the group was redesignated the 91st Reconnaissance Group , assigned to the Strategic Air Command , and activated on 1 July 1947 at Barksdale Air Force Base , Louisiana . After the United States Air Force became a separate service , the 91st was redesignated the 91st Strategic Reconnaissance Group on 10 November 1948 , and made a part of the 91st Strategic Reconnaissance Wing . It operated a variety of aircraft , including B - 17 ' s , RB - 17 ' s , B - 29 ' s and RB - 29 ' s , and B - 50 ' s . On 6 July 1950 , it was redesignated the 91st Strategic Reconnaissance Group ( Medium ) and equipped with the jet RB - 45C . The group was removed from operations on 10 February 1952 , when its squadrons were assigned directly to the wing , and inactivated on 28 May 1952 . The organization was redesignated as the 91st Operations Group on 29 August 1991 , and activated at Minot Air Force Base , North Dakota . on 1 September 1991 . Inactivated on 1 July 1994 , it was again activated on 1 February 1996 . The 91st OG is responsible for the operations of three missile squadrons maintaining a nuclear alert force of 150 LGM - 30G Minuteman III ICBM s and 15 alert facilities spread across of territory . The squadrons of the 91st OG are : 91st Bomb Group B - 17 ' s on exhibit . Two 91st B - 17 ' s survive , both currently at the National Museum of the United States Air Force at Dayton , Ohio .