Fokker Dr . I The Fokker Dr . I " Dreidecker " ( triplane ) was a World War I fighter aircraft built by Fokker - Flugzeugwerke . The Dr . I saw widespread service in the spring of 1918 . It became renowned as the aircraft in which Manfred von Richthofen gained his last 19 victories , and in which he was killed on 21 April 1918 . Design and development . In February 1917 , the Sopwith Triplane began to appear over the Western Front . Despite its single Vickers machine gun armament , the Sopwith swiftly proved itself superior to the more heavily armed Albatros fighters then in use by the " Luftstreitkräfte " . Fokker - Flugzeugwerke responded by converting an unfinished biplane prototype into the V . 4 , a small , rotary - powered triplane with a steel tube fuselage and thick cantilever wings , first developed during Fokker ' s government - mandated collaboration with Hugo Junkers . Initial tests revealed that the V . 4 had unacceptably high control forces resulting from the use of unbalanced ailerons and elevators . Instead of submitting the V . 4 for a type test , Fokker produced a revised prototype designated V . 5 . The most notable changes were the introduction of horn - balanced ailerons and elevators , as well as longer - span wings . The V . 5 also featured interplane struts , which were not necessary from a structural standpoint , but which minimized wing flexing . On 14 July 1917 , " Idflieg " issued an order for 20 pre - production aircraft . The V . 5 prototype , serial 101 / 17 , was tested to destruction at Adlershof on 11 August 1917 . Operational history . The first two pre - production triplanes were designated F . I , in accord with " Idflieg ' s " early class prefix for triplanes . These aircraft , serials 102 / 17 and 103 / 17 , were the only machines to receive the F . I designation and could be distinguished from subsequent aircraft by a slight curve to the tailplane leading edge . They were sent to " Jasta s " 10 and 11 for combat evaluation , arriving at Markebeeke , Belgium on 28 August 1917 . Richthofen first flew 102 / 17 on 1 September 1917 and shot down two enemy aircraft in the next two days . He reported to the " Kogenluft " ( " Kommandierender General der Luftstreitkräfte " ) that the F . I was superior to the Sopwith Triplane . Richthofen recommended that fighter squadrons be reequipped with the new aircraft as soon as possible . The combat evaluation came to an abrupt conclusion when " Oberleutnant " Kurt Wolff , " Staffelführer " of " Jasta " 11 , was shot down in 102 / 17 on 15 September , and " Leutnant " Werner Voss , " Staffelführer " of " Jasta " 10 , was killed in 103 / 17 on 23 September . The remaining pre - production aircraft , designated Dr . I , were delivered to " Jasta " 11 . " Idflieg " issued a production order for 100 triplanes in September , followed by an order for 200 in November . Apart from minor modifications , these aircraft were almost identical to the F . I . The primary distinguishing feature was the addition of wingtip skids , which proved necessary because the aircraft was tricky to land and prone to ground looping . In October , Fokker began delivering the Dr . I to squadrons within Richthofen ' s " Jagdgeschwader " I . Compared to the Albatros and Pfalz fighters , the Dr . I offered exceptional maneuverability . Though the ailerons were not very effective , the rudder and elevator controls were light and powerful . Rapid turns , especially to the right , were facilitated by the triplane ' s marked directional instability . " Vizefeldwebel " Franz Hemer of " Jasta " 6 said , " The triplane was my favorite fighting machine because it had such wonderful flying qualities . I could let myself stunt — looping and rolling — and could avoid an enemy by diving with perfect safety . The triplane had to be given up because although it was very maneuverable , it was no longer fast enough . " As Hemer noted , the Dr . I was considerably slower than contemporary Allied fighters in level flight and in a dive . While initial rate of climb was excellent , performance fell off dramatically at higher altitudes because of the low compression of the Oberursel Ur . II , a clone of the Le Rhône 9J rotary engine . As the war continued , chronic shortages of castor oil made rotary operation increasingly difficult . The poor quality of German " ersatz " lubricant resulted in many engine failures , particularly during the summer of 1918 . The Dr . I suffered other deficiencies . The pilot ' s view was poor during takeoff and landing . The cockpit was cramped and furnished with materials of inferior quality . Furthermore , the proximity of the gun butts to the cockpit , combined with inadequate crash padding , left the pilot vulnerable to serious head injury in the event of a crash landing . Wing failures . On 29 October 1917 , " Leutnant der Reserve " Heinrich Gontermann , " Staffelführer " of " Jasta " 15 , was performing aerobatics when his triplane broke up . Gontermann was fatally injured in the ensuing crash landing . " Leutnant der Reserve " Günther Pastor of " Jasta " 11 was killed two days later when his triplane broke up in level flight . Inspection of the wrecked aircraft showed that the wings had been poorly constructed . Examination of other high - time triplanes confirmed these findings . On 2 November , " Idflieg " grounded all remaining triplanes pending an inquiry . " Idflieg " convened a " Sturzkommission " ( crash commission ) which concluded that poor construction and lack of waterproofing had allowed moisture to damage the wing structure . This caused the wing ribs to disintegrate and the ailerons to break away in flight . In response to the crash investigation , Fokker improved quality control on the production line , particularly varnishing of the wing spars and ribs , to combat moisture . Fokker also strengthened the rib structures and the attachment of the auxiliary spars to the ribs . Existing triplanes were repaired and modified at Fokker ' s expense . After testing a modified wing at Adlershof , " Idflieg " authorized the triplane ' s return to service on 28 November 1917 . Production resumed in early December . By January 1918 , " Jastas " 6 and 11 were fully equipped with the triplane . Only 14 squadrons used the Dr . I as their primary equipment . Most of these units were part of " Jagdgeschwadern " I , II , or III . Frontline inventory peaked in late April 1918 , with 171 aircraft in service on the Western Front . Despite corrective measures , the Dr . I continued to suffer from wing failures . On 3 February 1918 , " Leutnant " Hans Joachim Wolff of " Jasta " 11 successfully landed after suffering a failure of the upper wing leading edge and ribs . On 18 March 1918 , Lothar von Richthofen , " Staffelführer " of " Jasta " 11 , suffered a failure of the upper wing leading edge during combat with Sopwith Camel s of No . 73 Squadron and Bristol F . 2B s of No . 62 Squadron . Richthofen was seriously injured in the ensuing crash landing . Postwar research revealed that poor workmanship was not the only cause of the triplane ' s structural failures . In 1929 , National Advisory Committee for Aeronautics ( NACA ) investigations found that the upper wing carried a higher lift coefficient than the lower wing — at high speeds it could be 2 . 55 times as much . The triplane ' s chronic structural problems destroyed any prospect of large - scale orders . Production eventually ended in May 1918 , by which time only 320 had been manufactured . The Dr . I was withdrawn from frontline service as the Fokker D . VII entered widespread service in June and July . " Jasta " 19 was the last squadron to be fully equipped with the Dr . I . Surviving triplanes were distributed to training and home defense units . Several training aircraft were reengined with the 75 kW ( 100 hp ) Goebel Goe . II . At the time of the Armistice , many remaining triplanes were assigned to fighter training schools at Nivelles , Belgium , and Valenciennes , France . Allied pilots tested several of these triplanes and found their handling qualities to be impressive . Experimental engines . Several Dr . Is were used as testbeds for experimental engines . One aircraft , designated V . 7 , was fitted with the Siemens - Halske Sh . III bi - rotary engine . The V . 7 exhibited exceptional rate of climb and ceiling , but it proved difficult to handle . Serial 108 / 17 was used to test the 118 kW ( 160 hp ) Goebel Goe . III , while serial 469 / 17 was used to test the 108 kW ( 145 hp ) Oberursal Ur . III . None of these engines were used on production aircraft . Postwar . Three triplanes are known to have survived the Armistice . Serial 528 / 17 was retained as a testbed by the " Deutschen Versuchsanstalt für Luftfahrt " ( German Aviation Research Institute ) at Adlershof . After being used in the filming of two movies , 528 / 17 is believed to have crashed sometime in the late 1930s . Serial 152 / 17 , in which Manfred von Richthofen obtained three victories , was displayed at the " Zeughaus " museum in Berlin . This aircraft was destroyed in an Allied bombing raid during World War II . In 1932 , Fokker assembled a Dr . I from existing components . It was displayed in the " Deutsche Luftfahrt - Sammlung " in Berlin . In 1943 , the aircraft was destroyed in an Allied bombing raid . Today , only a few original Dr . I artifacts survive in museums . Replica and reproduction aircraft . Large numbers of replica and reproduction aircraft have been built for both individuals and museums . Bitz Flugzeugbau GmbH built two Dr . I replicas for use in Twentieth Century Fox ’ s 1966 film " The Blue Max " . Because of the expense and scarcity of authentic rotary engines , most airworthy replicas are powered by a Warner Scarab or Continental R - 670 radial engine . A few , however , feature vintage Le Rhône 9 or reproduction Oberursel Ur . II rotary engines .