US MILITARY1956Bell Uh-1 Iroquois

In 1952 , the Army ident ifi ed a requ i rement for a new he l i copter to se rve as medica l evacuat ion (MEDEVAC) , ins t rument t ra iner and genera l u t i l i ty a i rc ra ft . The Army determined that current he l i copters were too large , underpowered, or were too complex to mainta in eas i l y. In November 1953 , rev i sed mi l i tary requ i rements were submi t ted to the Depar tment o f the Army

Twenty companies submi t ted des igns in the i r b id for the contrac t , inc lud ing Be l l He l i copter w i th the Mode l 204 and Kaman A i rc ra ft w i th a turb ine -powered vers ion o f the H-43 . On 23 February 1955 , the Army announced i ts dec i s ion , se lec t ing Be l l to bu i ld three cop ies o f the Mode l 204 for eva luat ion , des ignated as the XH-40

DEVELOPMENT

Powered by a prototype Lycoming YT53-L-1 (LTC1B-1) eng ine produc ing 700 shp (520 kW) , the XH-40 fi rs t fl ew on 20 October 1956

Two more prototypes were bu i l t i n 1957 , and the Army had prev ious ly ordered s ix YH-40 serv ice tes t a i rc ra ft , even be fore the fi rs t prototype had fl own

In March 1960 , the Army awarded Be l l a product ion contrac t for 100 a i rc ra ft , wh ich was des ignated as the HU-1A and offi c ia l l y named I roquo is , a f te r the nat ive Amer ican nat ions

The he l i copter qu ick ly deve loped a n ickname der ived f rom i t s des ignat ion o f HU-1 , wh ich came to be pronounced as "Huey" . The re fe rence became so popu lar that Be l l began cast ing the name on the he l i copter 's ant i - torque peda ls

The offi c ia l U .S . Army name was a lmost never used in prac t i ce Afte r September 1962 , the des ignat ion for a l l mode ls was changed to UH-1 under a

un ifi ed Depar tment o f De fense (DOD) des ignat ion sys tem, but the n ickname remained Whi le g lowing in pra i se for the he l i copter ' s advances over p i s ton-eng ined he l i copters ,

the Army repor ts f rom the serv ice tes ts o f the YH-40 found i t to be under-powered wi th the product ion T53-L-1A powerp lant produc ing a maximum cont inuous 770 shaft horsepower (570 k i lowatts )

The Army ind icated the need for improved, fo l l ow-on mode ls even as the fi rs t UH-1As were be ing de l i vered. In response , Be l l p roposed the UH-1B, equ ipped w i th the Lycoming T53-L-5 eng ine produc ing 960 shp (720 kW) and a longer cab in that cou ld accommodate seven passengers , or four s t re tchers and a medica l a t tendant . Army tes t ing o f the UH-1B s tar ted in November 1960 , w i th the fi rs t product ion a i rc ra ft de l i ve red in March 1961

MODEL 204

The Mode l 205 p ro to type fl ew on 16 Augus t 1960 Whi le ea r l i e r " sho r t -body" Hueys were a success , the A rmy wanted a ve rs ion tha t cou ld ca rry

more t roops . Be l l ' s so lu t i on was to s t re t ch the HU-1B fuse lage by 41 in (104 cm) and use the ex t ra space to fi t fou r sea t s next t o the t ransmiss ion , fac ing ou t . Sea t ing capac i t y i nc reased to 15 , i nc lud ing c rew

The en la rged cab in cou ld a l so accommodate s i x s t re t chers and a med ic , two more than the ea r l i e r mode l s

I n p lace o f t he ea r l i e r mode l ' s s l i d ing s ide doo rs w i th a s ing le w indow, l a rger doo rs were fi t ted wh ich had two w indows , p lus a sma l l h inged pane l w i th an op t i ona l w indow, p rov id ing access t o the cab in . The doo rs and h inged pane l s were qu ick ly removab le , a l l ow ing the Huey to be fl own in a "doo rs off " confi gura t ion

Seven p re -p roduc t ion /p ro to type a i rc ra f t were de l i ve red and tes ted a t Edwards AFB s ta r t i ng i n March 1961 . The 205 was i n i t i a l l y equ ipped w i th a 44 - foo t (13 .4 m) ma in ro to r and a Lycoming T53 -L-9 eng ine w i th 1 ,100 shp (820 kW) . The ro to r was l eng thened to 48 fee t (14 .6 m) w i th a cho rd o f 21 in (53 cm) . The ta i l boom was a l so l eng thened , i n o rder t o accommodate the l onger ro to r b lades . A l together , the mod ifi ca t ions resu l ted in a g ross we igh t capac i t y o f 9 ,500 lb (4 ,309 kg ) . The A rmy o rdered p roduc t i on o f t he 205 in 1963 , p roduced w i th a T53 -L-11 eng ine fo r i t s mu l t i - fue l capab i l i t y

The p ro to types were des igna ted as YUH-1D and the p roduc t i on a i rc ra f t was des igna ted as the UH-1D

I n 1966 , Be l l i n s ta l l ed the 1 ,400 shp (1 ,000 kW) Lycoming T53 -L -13 eng ine to p rov ide more power fo r the a i rc ra f t . The p i t o t tube was re loca ted f rom the nose to the roo f o f t he cockp i t , t o p reven t damage du r ing l and ing . Produc t ion mode l s i n th i s confi gura t ion were des igna ted as the UH-1H

MODEL 205

The UH-1 has a meta l fu se lage o f semi -monocoque cons t ruc t ion w i th tubu la r l and ing sk ids and two ro to r b lades on the ma in ro to r

Ear ly UH-1 mode l s fea tu red a s ing le Lycoming T53 tu rbosha f t eng ine in ve rs ions w i th power ra t ings f rom 700 shp (522 kW) to 1 ,400 shp (1 ,040 kW)

La te r UH-1 and re la ted mode l s wou ld fea tu re tw in eng ines and fou r-b lade ro to rs A l l a i rc ra f t i n the UH-1 fami ly have s im i la r cons t ruc t ion . The UH-1H i s the most -p roduced

vers ion , and i s rep resen ta t i ve o f a l l t ypes . The ma in s t ruc tu re cons i s t s o f two l ong i tud ina l ma in beams tha t run under the passenger cab in t o the nose and back to the ta i l boom a t tachment po in t . The ma in beams a re separa ted by t ransverse bu lkheads and p rov ide the suppor t ing s t ruc tu re fo r t he cab in , l and ing gear , under-fl oo r fue l t anks , t ransmiss ion , eng ine and ta i l boom. The ma in beams a re j o ined a t the l i f t beam, a sho r t a luminum g i rder s t ruc tu re tha t i s a t tached to the t ransmiss ion v ia a l i f t l i nk on the top and the ca rgo hook on the bo t tom and i s l oca ted a t the a i rc ra f t ' s cen t re o f g rav i t y. The l i f t beams were changed to s tee l l a te r i n the UH-1H ' s l i f e , due to c rack ing on h igh - t ime a i r f rames . The semi -monocoque ta i l boom a t taches t o the fuse lage w i th fou r bo l t s

The UH-1H ' s dynamic componen ts i nc lude the eng ine , t ransmiss ion , ro to r mast , ma in ro to r b lades , t a i l ro to r d r i vesha f t , and the 42 -degree and 90 -degree gearboxes . The t ransmiss ion i s o f a p laneta ry t ype and reduces the eng ine ' s ou tpu t t o 324 rpm a t the ma in ro to r. The two -b laded , semi - r i g id ro to r des ign , w i th p re -coned and under- s lung b lades , i s a deve lopment o f ea r l y Be l l mode l des igns , such as the Be l l 47 w i th wh ich i t sha res common des ign fea tu res , i nc lud ing a dampened s tab i l i ze r ba r

DESIGNS

X H - 4 0 Y H - 4 0 H U - 1 A T H - 1 A X H - 1 A H U - 1 B N U H - 1 B U H - 1 C Y U H - 1 D U H - 1 D H H - 1 D U H - 1 E N U H - 1 E T H - 1 E U H - 1 F T H - 1 F U H - 1 H C U H - 1 H E H - 1 H H H - 1 H J U H - 1 T H - 1 H U H - 1 G U H - 1 J H H - 1 K

VARIANTSAll Information Provided from Wikipedia.org

TH-1L UH-1L UH-1M UH-1N UH-1P EH-1U UH-1V EH-1X UH-1Y