Aircraft Hose

8/20/2019 Aircraft Hose

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Aircraft

Hoses

Khagendra kumar yad

M-tech (AME)


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contentHose-Introduction

HOSES :SE!I"E #I!ES

Hose Materia$s and "onstruction

Hose Identi%cation

Storage of hose

Hose insta$$ation


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Hose

A mu$ti&$e-$ayered 'ei$e conduit through *hich

'uid is conveyed from one &oint to another+,$ei$e hose is used in aircraft 'uid systems to

connect moving &arts *ith stationary &arts in$ocations suect to viration or *here a greatamount of 'eii$ity is needed+ It can a$so serve as a

connector in meta$ tuing systems+

.he hoses have een c$assi%ed in t*o grou&s :

/O01 A : ,ue$2 Oi$2 &neumatic and hydrau$ic&ressure

hoses+

/O01 3 : A$$ other hoses $ike hydrau$ic return $ine

and instruments hoses etc+


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HOSES :SE!I"E #I!ES

She$f #ife :

.he tota$ storage4she$f $ife of oth ty&es of hosessha$$ e $imited to 56 years from the cure date ofmanufacture+

7uring storage2 &eriodic ins&ection shou$d e

carried out once a year for signs of deterioration2*eather cracks2 signs of corrosion on end %ttingsetc+ and hose &ressure tested to 5-548 times the*orking &ressure every t*o years+

3efore insta$$ation on aircraft &ressure test shou$de carried out at 5-548 times the *orking &ressure+

Service #ife :

/rou& A hoses 9 ma+ years etenda$e u&to ; years


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Hose Materia$s and "onstruction The two basic hose materials are synthetic rubber and

polytetrafuoroethylene (PTFE).

To meet the requirements o strength, durability, andworability, among other actors, synthetics are usedin place o pure rubber. !ynthetic materials mostcommonly used in the manuacture o fe"ible hose

are #una$%, neoprene, butyl, ethylene propylenediene rubber (EP&') and Tefon.

ne material which is widely used or themanuacture o hose or engine and hydraulic

systems is polytetrafuoroethylene (PTFE). Thismaterial is chemically inert, is una*ected by thesynthetic oils and fuids used in aircrat systems,operates satisactorily at high fuid and ambient

temperature and normally has an unlimited shel lie.


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+ow, 'edium, and igh Pressure oses

+ow pressure - below /0 psi. Fabric braidreinorcement.


1sed or instruments mounted on panels equipped with

2ibration isolators and the rudder.


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'edium pressure - up to 3,000 psi. ne wire

braid reinorcement. !maller si4es carry upto3,000 psi. +arger si4es carry pressure up to5,/00 psi.



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igh pressure - all si4es up to 3,000 psi

operating pressures.



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High &ressure hose assem$y

• 6onsist o an 7nner tube or lining co2ered by one or two closelywo2en wire braids, either moulded or sandwiched between thesynthetic rubber o the tube or wo2en on the surace o the tube.

• The whole may be enclosed by an outer co2er, the purpose is toprotect the other parts o the hose, to resist abrasion and thee*ects o weather and in some case, to pro2ide a degree o 8reresistance.


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Hose Identi%cation!ynthetic rubber hoses with rubber co2ers are

identi8ed with the military speci8cation number,

the si4e by dash number, the quarter and year ocure or manuacture, and the manuacturer9scode identi8cation number or ederal supply codenumber printed along their layline(8g :). The

layline is a legible maring parallel to thelongitudinal a"is o a hose used in determiningthe straightness or lay o the hose.

!ynthetic rubber hoses with wire braid co2er are

identi8ed by bands (8g #)wrapped around thehose ends and at inter2als along the length o thehose.


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Hose Identi%cation

MI#-H--56 ?4=5(6;


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Hose Identi%cation


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Si@ing

The si4e o a fe"ible hose is identi8ed by the dash ($)number,

which is the 7& o the hose e"pressed in 5;ths o an inch. Fore"ample, the 7& o a $;< hose is < inches. For a ew hose stylesthis is the nominal and not the true 7&.

"ure 7ate

!ynthetic rubber hoses will deteriorate rom aging. : cure date isused to ensure that they do not deteriorate beyond material andperormance speci8cations. The cure date is the quarter and yearthe hose was manuactured. For e"ample, 5=>? means the hosewas made during the 8rst quarter (5 @an to 35 'ar) o 5?>?. The

cure date limits the length o time a rubber hose can be stored,in bul or as an assembly, prior to being placed into ser2ice. Thestorage or shel lie or rubber hose is < years. For the hosemanuactured in 5=>?, the storage or shel lie will end on the

35st o 'arch 5??3.

Hose Identi%cation


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Storage of hose:ircrat hoses and hose assemblies should be storeduncoiled and supported so as to release stresses.

Temperature : The storage temperature should be between

50 deg. F and 70 deg. F and the distance between the

stored articles and the source of heat should be more than 3

feet.

Humidity : The relatie humidity in the store room should be

around !5 percent.

"ight : #ubber parts should not be e$posed to strong light

e.g. direct rays of sun. The store rooms should be %ept as

dar% as practicable.


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i $$ i


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Hose insta$$ation

'achine Tolerance

ose assemblies must not be installed in a manner

that will cause a mechanical load on the hose.

Pro2ide slac or bend in the hose line to pro2ide orchanges in length that will occur when pressure is

applied.


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'otion :bsorption

Pro2ide additional bend radius when lines aresubAect to fe"ing and remember that the metal end8ttings are not fe"ible. Place line support clampsso as not to restrict hose fe"ing.

Hose insta$$ation


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Twisting

bser2e linear stripe. The hose must not betwisted. igh pressures applied to a twisted hosemay cause ailure or loosen the nut.

Hose insta$$ation


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'inimum #end Badius

ose rupture or leaage may result rom bendingtoo close to the hose=8tting connection.

Hose insta$$ation


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ose !train

Belie2e sharp bends, a2oid strain or hose collapse,and mae cleaner installations by using :eroquipelbows or other adapter 8ttings. Pro2ide as large abend radius as possible. %e2er use less than the

recommended minimum bend radius speci8ed orthe hose.

Hose insta$$ation


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Aircraft Hose

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