xov xwm

Txij li xyoo 1950 los,Cov khoom siv fiberglass reinforced compositestau siv rau hauv cov khoom tsis muaj lub nra hnyav ntawm lub dav hlau helicopter, xws li fairings thiab inspection hatches, txawm hais tias lawv daim ntawv thov tau txwv heev.

Kev nce qib tshiab hauv cov khoom siv sib xyaw rau cov dav hlau tau tshwm sim hauv xyoo 1960 nrog kev tsim cov iav fiber ntxiv rau cov hniav rotor. Qhov no qhia tau hais tias muaj cov txiaj ntsig zoo ntawm cov khoom sib xyaw - lub zog qaug zog zoo dua, kev hloov pauv ntau txoj kev thauj khoom, cov yam ntxwv qeeb qeeb ntawm kev tawg, thiab qhov yooj yim ntawm kev txhaj tshuaj molding - uas tau pom tseeb hauv cov ntawv thov hniav rotor. Qhov tsis muaj zog ntawm cov khoom sib xyaw ua los ntawm fiber - lub zog interlaminar qis thiab kev nkag siab rau cov yam ntxwv ib puag ncig - tsis cuam tshuam rau kev tsim hniav rotor lossis daim ntawv thov.

Txawm hais tias cov hniav hlau feem ntau muaj lub neej ua haujlwm tsis pub tshaj 2000 teev, cov hniav sib xyaw ua ke tuaj yeem ua tiav lub neej ntev tshaj 6000 teev, tej zaum yuav tsis paub meej, thiab ua rau muaj kev saib xyuas raws li qhov xwm txheej. Qhov no tsis yog tsuas yog txhim kho kev nyab xeeb ntawm lub dav hlau xwb tab sis kuj txo qhov nqi tag nrho lub neej ntawm cov hniav, ua rau muaj txiaj ntsig zoo rau kev lag luam. Cov txheej txheem yooj yim, yooj yim rau kev ua haujlwm compression molding thiab kho rau cov khoom sib xyaw, ua ke nrog lub peev xwm los kho lub zog, kev tawv (suav nrog cov yam ntxwv damping), ua rau muaj kev txhim kho aerodynamic profile zoo dua thiab kev ua kom zoo dua hauv kev tsim hniav rotor, nrog rau kev ua kom zoo dua ntawm cov qauv rotor. Txij li xyoo 1970, kev tshawb fawb txog cov airfoids tshiab tau ua rau muaj ntau cov qauv hniav helicopter ua haujlwm zoo. Cov airfoids tshiab no muaj kev hloov pauv los ntawm symmetric mus rau tag nrho curved, asymmetric designs, ua tiav qhov siab tshaj plaws lift coefficients thiab cov lej Mach tseem ceeb, txo cov coefficients rub, thiab kev hloov pauv tsawg kawg nkaus hauv cov coefficients moment. Kev txhim kho hauv cov duab ntawm cov hniav rotor - los ntawm rectangular mus rau swept, tapered tips; parabolic swept downward-curved tips; rau cov lus qhia BERP nyias nyias uas tau hloov kho tshiab - tau txhim kho kev faib khoom thauj aerodynamic, kev cuam tshuam vortex, kev co, thiab cov yam ntxwv suab nrov, yog li ua rau rotor ua haujlwm tau zoo dua.

Tsis tas li ntawd xwb, cov neeg tsim qauv tau siv ntau yam kev sib koom ua ke ntawm kev ua kom zoo dua ntawm cov cua tshuab ntawm lub rotor thiab cov qauv ntawm lub cev, ua ke cov khoom siv sib xyaw ua ke nrog kev tsim qauv rotor kom ua tiav kev ua haujlwm ntawm cov hniav thiab kev txo qis kev co/suab nrov. Yog li ntawd, thaum xyoo 1970s lig, yuav luag txhua lub dav hlau tshiab tau siv cov hniav sib xyaw ua ke, thaum hloov kho cov qauv qub nrog cov hniav hlau rau cov hniav sib xyaw ua ke tau ua tiav cov txiaj ntsig zoo heev.

Cov kev xav tseem ceeb rau kev siv cov khoom sib xyaw ua ke hauv cov qauv dav hlau helicopter suav nrog: cov nplaim nkhaus ntawm sab nraud ntawm lub dav hlau helicopter, nrog rau kev thauj khoom tsawg, ua rau lawv tsim nyog rau kev tsim cov khoom sib xyaw ua ke los txhim kho kev ua kom puas tsuaj thiab xyuas kom muaj kev nyab xeeb thiab kev ua haujlwm txhim khu kev qha; qhov kev xav tau rau kev txo qhov hnyav hauv cov qauv dav hlau rau ob qho tib si dav hlau siv tau thiab dav hlau tawm tsam; thiab cov kev xav tau rau cov qauv nqus kev sib tsoo thiab kev tsim qauv zais cia. Txhawm rau daws cov kev xav tau no, US Army Aviation Applied Technology Research Institute tau tsim Advanced Composite Airframe Program (ACAP) hauv xyoo 1979. Txij li xyoo 1980, thaum cov dav hlau helicopters zoo li Sikorsky S-75, Bell D292, Boeing 360, thiab European MBB BK-117 nrog cov dav hlau sib xyaw ua ke pib sim dav hlau, mus rau Bell Helicopter txoj kev koom ua ke ntawm V-280's composite tis thiab fuselage hauv xyoo 2016, kev txhim kho ntawm cov dav hlau sib xyaw ua ke tau ua tiav ntau yam. Piv rau cov dav hlau uas siv cov hlau txhuas ua piv txwv, cov dav hlau uas ua los ntawm cov khoom sib xyaw ua ke muaj txiaj ntsig zoo rau qhov hnyav ntawm cov dav hlau, cov nqi tsim khoom, kev ntseeg siab, thiab kev saib xyuas, ua tau raws li cov hom phiaj ntawm ACAP raws li tau teev tseg hauv Rooj 1-3. Yog li ntawd, cov kws tshaj lij hais tias kev hloov cov dav hlau uas siv cov hlau txhuas ua ke muaj qhov tseem ceeb sib piv rau kev hloov pauv xyoo 1940 los ntawm cov dav hlau uas siv ntoo ua cov ntaub mus rau cov qauv hlau.

Ntawm chav kawm, qhov dav ntawm kev siv cov khoom sib xyaw hauv cov qauv airframe yog txuas nrog cov qauv tsim helicopter (kev ntsuas kev ua tau zoo). Tam sim no, cov khoom sib xyaw suav txog 30% txog 50% ntawm qhov hnyav ntawm cov qauv airframe hauv cov helicopters nruab nrab thiab hnyav, thaum cov tub rog / pej xeem thauj helicopters siv cov feem pua ​​​​​​ntau dua, ncav cuag 70% txog 80%. Cov khoom sib xyaw feem ntau yog siv rau hauv cov khoom fuselage xws li lub tail boom, vertical stabilizer, thiab horizontal stabilizer. Qhov no ua haujlwm ob lub hom phiaj: txo qhov hnyav thiab qhov yooj yim ntawm kev tsim cov nto nyuaj xws li ducted vertical stabilizers. Cov qauv nqus dej kuj siv cov khoom sib xyaw los ua kom txuag tau qhov hnyav. Txawm li cas los xij, rau cov helicopters sib dua thiab me me nrog cov qauv yooj yim dua, cov khoom thauj qis dua, thiab phab ntsa nyias, kev siv cov khoom sib xyaw yuav tsis tas yuav tsim nyog.