(i)
At least 200 start-up clutch engagements must be accomplished–
(1)
So that the shaft on the driven side of the clutch is accelerated; and
(2)
Using a speed and method selected by the applicant.
(j)
For multiengine helicopters for which the use of 30-minute OEI power is requested, .ve runs must be made at 30-minute OEI torque and the maximum speed for use with 30-minute OEI torque, in which each engine, in sequence, is made inoperative and the remaining engine(s) is runfor a30-minuteperiod.
(k)
For multiengine rotorcraft for which the use of continuous OEI power is requested, .ve runs must be made at continuous OEI torque and the maximum speed for use with continuousOEI torque,in which each engine,in sequence,is madeinoperative and the remaining engine(s) is runfor a1-hourperiod.
Amdt. 27-29, E.. 10/17/94
FAR 27.927 : Additional tests
(a)
Any additional dynamic, endurance, and operational tests, and vibratory investi-gations necessary to determine that the rotor drive mechanism is safe, must be performed.
(b)
If turbine engine torque output to the transmission can exceed the highest engine or transmission torque rating limit, and that output is not directly controlled by the pilot under normal operating conditions (such as where the primary engine power control is accomplished through the .ight control), the following test must be made :
(1)
Under conditions associatedwith all engines operating, make200 applications, for 10 seconds each, of torque that is at least equal to the lesser of–
(i)
The maximumtorque usedin meeting Sec.27.923plus10percent; or
(ii)
The maximum attainable torque output of the engines, assuming that torque limiting devices, if any, function properly.
(2)
For multiengine rotorcraft under conditions associated with each engine, in turn, becoming inoperative, apply to the remaining transmission torque in-puts the maximum torque attainable under probable operating conditions, assuming that torque limiting devices, if any, function properly. Each trans-mission input must be tested at this maximum torque for at least 15 minutes.
(3)
[The tests prescribed in this paragraphmust be conducted on the rotorcraft atthe maximum rotational speedintendedforthepowercondition of thetest and the torque must be absorbed by the rotors to be installed, except that otherground or .ighttestfacilitieswith otherappropriatemethodsof torque absorption may be used if the conditions of support and vibration closely simulate the conditions that would exist during a test on the rotorcraft.]
(c) It must be shown by tests that the rotor drive system is capable of operating under autorotative conditions for 15 minutes after the loss of pressure in the rotor drive primary oil system.
Amdt. 27-23, E.. 10/3/88
FAR 27.931 : Shafting critical speed
(a)
The critical speeds of any shafting must be determined by demonstration, except that analytical methods may be used if reliable methods of analysis are available for the particular design.
(b)
If any critical speedlies within, or close to, the operating rangesforidling,power on, and autorotative conditions, the stresses occurring at that speed must be within safe limits. This must be shown by tests.
(c)
If analytical methods are used and show that no critical speed lies within the per-missible operating ranges, the margins between the calculated critical speeds and thelimits of the allowable operating rangesmustbe adequateto allowforpossible variations between the computed and actual values.
FAR27.935 :Shaftingjoints
Eachuniversaljoint, slipjoint, and other shaftingjoints whoselubricationis necessary for operation musthaveprovisionforlubrication.
FAR 27.939 : Turbine engine operating characteristics
(a)
Turbine engine operating characteristics must be investigated in .ight to determine thatnoadversecharacteristics(suchasstall,surge,or .ameout) arepresent,to a hazardous degree, during normal and emergency operation within the range of operating limitations of the rotorcraft and of the engine.
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 4(105)
