RMIT Flight Training RMIT飞行训练(19)

曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

- Holding = maximum Endurance
Revision:
 Power
 Drag
Definitions:
 Range
- air distance travelled for a given fuel burn off (distance)
 Endurance
- time in flight for a given amount of fuel (time)
 Range Speed
 Endurance Speed
Brief 30
RMIT Flight Training Range & Endurance
RMIT Instructor Rating Mass Briefs Issue 1 /2004 Page 2
Principles:
 Maximum Range
- Power is defined as: force  velocity
Preq = Treq  TAS
= D  TAS
P / TAS ratio = D  TAS
TAS
= D
Maximum Range occurs when Total Drag is a minimum!
 Maximum Endurance
- Endurance is dependant on minimum fuel flow for given time in air.
- Fuel flow depends upon power setting. So minimum fuel flow occurs at
minimum power for S&L flight.
Maximum Endurance occurs at minimum power!
Brief 30
RMIT Flight Training Range & Endurance
RMIT Instructor Rating Mass Briefs Issue 1 /2004 Page 3
Considerations:
 Airspeed
- = decreased R and decreased E
-  = decreased R and decreased E
 Weight
-  = decreased R (L  fly faster or AoA  D)
- = decreased E (W = Preq FF)
- = increased R and decreased E
 Wind
- HW = decreased R and no change to E
- TW = increased R and no change to E
 Power
-  = decreased R (P  TAS constant P/TAS)
- = decreased E (P  FF)
- = decreased R and decreased E (can’t maintain S&L  P)
 Altitude
-  = increased R (ALT,  D/TAS)
- = decreased E (ALT,  P and FF)
- = decreased R and increased E
Airmanship:
- Set power according to cruise tables in POH
- Lean mixture in cruise
- Never exceed MTOW or VNE
RMIT Flight Training Range & Endurance
PITOT / STATIC SYSTEMS
Aim: To understand the principles of operation behind a pitot / static system,
considering the possible errors and limitations involved.
Application:
- Used when relying on the pressure instruments.
- ASI, ALT and VSI.
Revision:
 Static Pressure
- pressure due to weight of air molecules pushing down. Reduces with
increased altitude.
 Dynamic Pressure
- pressure due to relative movement. Depends on density and velocity.
- PD =
 Total Pressure
- PT =
Definitions:
 Static Vent
- measures PS and usually flush-mounted on fuselage side.
Brief 28
RMIT Flight Training Pitot/ Static Systems
 Pitot Tube
- measures PT and mounted where airflow not greatly disturbed. Usually on
outer wing section.
- pitot heat provided to guard against ice.
 Alternate Static Source
- emergency static port, found in cockpit, used in an emergency.
- slightly lower than atmosphere pressure due to slight suction created by
door seals.
Principles:
 A typical pitot/ static system is shown below:
 Airspeed Indicator (ASI)
- measures PD (½V2) and extracts V to show aircraft velocity.
- diaphragm is used filled with pitot pressure (PT) and PS surrounding it. The
diaphragm will position itself, and the pointer will then relate the difference.
PD = PT – PS
Brief 28
RMIT Flight Training Pitot/ Static Systems
 Altimeter (ALT)
- uses PS only and relates it to height
- contains an aneroid capsule exposed to PS from the static vent. Fixed
diaphragm contains air as a reference. As aircraft climbs, PS reduces and
the capsule expands driving the pointer via mechanical linkages.
- time lag does exist
 Vertical Speed Indicator (VSI)
- uses PS only, and works on the principles of converting rate of change of
PS to a rate of change of altitude
- instrument is a flexible capsule exposed to PS housing a choke valve.
- aircraft descends, PS increases. This pressure is fed into the capsule and
the choke valve. Therefore there is a delay to the increase in PS in the
capsule. The capsule then expands driving a pointer until the pressure
equalises with that in the choke valve.
Considerations:
 Instrument Errors
- due to imperfections in the design and installation.
 Instrument Lag
- response time of pressure instruments can be slow due to long lines or
rapid pressure changes.
 Position Error
　
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：RMIT Flight Training RMIT飞行训练(19)