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Northrop’s N-9MB

Flight Journal - - CONTENTS - by Frank B. Mormillo

Un­likely Sur­vivor: Northrop’s N-9MB

Atruly unique and pi­o­neer­ing air­craft, the Planes of Fame Air Mu­seum’s Northrop N-9MB is the only sur­vivor of a World War II pro­gram in­tended to pro­vide the U.S. Army Air Forces with an in­ter­con­ti­nen­tal bomber em­ploy­ing Jack Northrop’s rev­o­lu­tion­ary fly­ing-wing con­cept. The last of four 1/3-scale de­vel­op­ment air­craft (a 60-foot wingspan) in­tended to in­ves­ti­gate var­i­ous as­pects of the flight-con­trol sys­tems that would be used in the 172-foot wingspan bombers, the N-9MB flew for the first time in 1944. It was the first air­plane to use a fully hy­draulic flight-con­trol sys­tem with air­speed-sen­si­tive feed­back. The other 1/3- scale Northrop fly­ing-wing de­vel­op­ment air­craft were two N-9Ms (the first of which took to the air for its ini­tial flight on De­cem­ber 27, 1942) and the N-9MA. The N-9Ms and the N-9MA were pow­ered by a pair of 275hp Me­nasco C-6S-4 6-cylin­der, air-cooled in­line en­gines, while the N-9MB flew with a pair of 300hp Franklin 0-540-7 6-cylin­der, air-cooled op­posed en­gines. With the en­gines in pusher con­fig­u­ra­tion, the N-9Ms fea­tured steel-tube cen­ter sec­tions cov­ered with wood and me­tal pan­els, and wood outer-wing sec­tions. They had tri­cy­cle land­ing gear with an ex­tended, re­tractable tail­wheel bumper to pre­vent dam­age to the pro­pel­lers on take­off ro­ta­tion.

The N-9M made about 50 flights for a to­tal of 30 hours in the air be­fore be­ing lost in early 1943 in a fa­tal crash, pos­si­bly due to aero­dy­namic forces in­duc­ing full-aft pres­sure on the con­trol col­umn. The re­main­ing three N-9Ms flew suc­cess­fully, how­ever, for hun­dreds of hours in a three-year pro­gram that pro­vided valu­able in­for­ma­tion for the Northrop B-35 Fly­ing Wing bomber (the pro­to­type of which flew for the first time on June 25, 1946). They also pro­vided prospec­tive fly­ing-wing bomber pi­lots with ex­pe­ri­ence in the han­dling char­ac­ter­is­tics of fly­ing-wing air­craft.

A pro­gram steeped in con­tro­versy, the pis­ton-pow­ered B-35 and jet-pow­ered B-49 Fly­ing Wings were ad­vanced for their time and the sub­ject of leg­end. At one time, as many as 270 of the big bombers (in­clud­ing pro­to­types and de­vel­op­ment air­craft) had been or­dered in nine dis­tinct vari­a­tions. The pis­ton-pow­ered B-35s had four 3,000hp Pratt & Whit­ney R-4360-17 Wasp Ma­jor en­gines in pusher con­fig­u­ra­tion, while the jet-pow­ered B-49s came in eight- (4,000-pound thrust Al­li­son J-35-A-15 tur­bo­jets) and six-en­gine (5,600-pound thrust Al­li­son J-35-A-19 tur­bo­jets) con­fig­u­ra­tions. It ap­pears, how­ever, that only 28 of the bombers were ac­tu­ally built or un­der con­struc­tion, and only six of them ever flew (two XB-35s, one YB-35, two YB-49s, and one YRB-49A) be­fore the ma­jor­ity of the pro­gram

was canceled on Oc­to­ber 29, 1949, al­though work did con­tinue on the sole YRB-49A re­con­nais­sance vari­ant un­til 1951. All the air­craft in­volved in the

Fly­ing Wing bomber pro­gram were or­dered to be scrapped, with the YRB-49A be­ing the last to go, in Oc­to­ber 1953.

The N-9MB some­how sur­vived the scrap­ping or­der, how­ever, and was even­tu­ally ob­tained by Ed­ward T. Maloney, founder of the Planes of Fame

Air Mu­seum, in the 1950s. The re­mains of the largely wooden air­plane lan­guished for three decades be­fore a team of mu­seum vol­un­teers be­gan the daunt­ing task of restor­ing the his­toric air­craft to fly­ing con­di­tion in 1981. Af­ter 13 years of ded­i­cated work, the re­stored N-9MB made its first taxi test at the air­port in Chino, Cal­i­for­nia, on Novem­ber 6, 1994, and its first pub­lic flight at Chino on Novem­ber 11, 1994. The pi­lot for the Fly­ing Wing’s early flights was Don Lykins, the mu­seum’s chair­man of the board, but

Ron Hack­worth, di­rec­tor of the N-9MB’s restora­tion ef­fort, be­came its pri­mary pi­lot for the next two decades. Airline pi­lot and mu­seum vol­un­teer David Vopat is now the Fly­ing Wing’s pri­mary dis­play pi­lot. The N-9MB is a reg­u­lar par­tic­i­pant in the an­nual Planes of Fame Air­show at the Chino Air­port, and fre­quently flies at other events as well, some as far as 500 miles away. With its bright yel­low-and-blue color and unique con­fig­u­ra­tion, the N-9MB stands out wher­ever it goes.

Ron Hack­worth fly­ing the re­stored Northrop N-9MB over South­ern Cal­i­for­nia.

Above:

Don Lykins per­formed the test flights of the re­stored N-9MB and was even al­lowed to work from a hangar at Ed­wards Air Force Base for three days dur­ing the high-speed por­tions of that test pro­gram, in­tended to reval­i­date Jack Northrop’s work. (This photo was taken over the nor­mally dry lake at Ed­wards AFB, which was flooded with win­ter rain­wa­ter at the time.)

Left: The cock­pit of the re­stored N-9MB.

Above: Vol­un­teers of the Planes of Fame Air Mu­seum work on the restora­tion of the N-9MB. Al­most all the badly rot­ted wood air­frame had to be re-cre­ated, with the de­te­ri­o­rated parts used only for pat­terns.

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