Yahoo奇摩 網頁搜尋

  1. 約 613 項搜尋結果

  1. 推力計 相關

    廣告
  1. The thrust-to-weight ratio is calculated by dividing the thrust (in SI units – in newtons) by the weight (in newtons) of the engine or vehicle. Note that the thrust can also be measured in pound-force (lbf), provided the weight is measured in pounds (lb). Division using these two values still gives the numerically correct (dimensionless ...

  2. Trent 800. The 97.4 in (247 cm) fan with 26 blades gives a 5:1 bypass ratio [2] The Rolls-Royce Trent 700 is a high-bypass turbofan produced by Rolls-Royce plc to power the Airbus A330 . Rolls-Royce was studying a RB211 development for the A330 at its launch in June 1987. It was first selected by Cathay Pacific in April 1989, first ran in ...

    • Principle and Uses
    • Types of Thrust Reversal Systems
    • Operation
    • Effectiveness
    • Thrust Reversal-Related Accidents and Incidents
    • See Also
    • External Links

    A landing roll consists of touchdown, bringing the aircraft to taxi speed, and eventually to a complete stop. However, most commercial jet engines continue to produce thrust in the forward direction, even when idle, acting against the deceleration of the aircraft. The brakes of the landing gear of most modern aircraft are sufficient in normal circu...

    Small aircraft typically do not have thrust reversal systems, except in specialized applications. On the other hand, large aircraft (those weighing more than 12,500 lb) almost always have the ability to reverse thrust. Reciprocating engine, turbopropand jet aircraft can all be designed to include thrust reversal systems.

    In most cockpit setups, reverse thrust is set when the thrust levers are on idle by pulling them farther back. Reverse thrust is typically applied immediately after touchdown, often along with spoilers, to improve deceleration early in the landing roll when residual aerodynamic lift and high speed limit the effectiveness of the brakes located on th...

    The amount of thrust and power generated are proportional to the speed of the aircraft, making reverse thrust more effective at high speeds.[self-published source?] For maximum effectiveness, it should be applied quickly after touchdown. If activated at low speeds, foreign object damage is possible. There is some danger of an aircraft with thrust r...

    In-flight deployment of reverse thrust has directly contributed to the crashes of several transport-type aircraft: 1. On 4 July 1966 an Air New Zealand Douglas DC-8-52 with the registration ZK-NZBcrashed on takeoff on a routine training flight from Auckland International Airport due to reverse thrust applied during a simulated failure of no.4 engin...

    "Power Jets thrust spoiler which can give negative thrust for braking" – a 1945 Flight article on new engine developments showing a Power Jetsreverse thrust device
    • Methods
    • Vectoring Nozzles
    • Operational Examples
    • List of Vectored Thrust Aircraft

    Rockets and ballistic missiles

    Nominally, the line of action of the thrust vector of a rocket nozzle passes through the vehicle's centre of mass, generating zero net moment about the mass centre. It is possible to generate pitch and yaw moments by deflecting the main rocket thrust vector so that it does not pass through the mass centre. Because the line of action is generally oriented nearly parallel to the roll axis, roll control usually requires the use of two or more separately hinged nozzles or a separate system altoge...

    Tactical missiles and small projectiles

    Some smaller sized atmospheric tactical missiles, such as the AIM-9X Sidewinder, eschew flight control surfacesand instead use mechanical vanes to deflect rocket motor exhaust to one side. By using mechanical vanes to deflect the exhaust of the missile's rocket motor, a missile can steer itself even shortly after being launched (when the missile is moving slowly, before it has reached a high speed). This is because even though the missile is moving at a low speed, the rocket motor's exhaust h...

    Aircraft

    Most currently operational vectored thrust aircraft use turbofans with rotating nozzles or vanes to deflect the exhaust stream. This method can successfully deflect thrust through as much as 90 degrees, relative to the aircraft centreline. However, the engine must be sized for vertical lift, rather than normal flight, which results in a weight penalty. Afterburning (or Plenum Chamber Burning, PCB, in the bypass stream) is difficult to incorporate and is impractical for take-off and landing th...

    Thrust-vectoring flight control (TVFC) is obtained through deflection of the aircraft jets in some or all of the pitch, yaw and roll directions. In the extreme, deflection of the jets in yaw, pitch and roll creates desired forces and moments enabling complete directional control of the aircraft flight path without the implementation of the conventi...

    Aircraft

    An example of 2D thrust vectoring is the Rolls-Royce Pegasus engine used in the Hawker Siddeley Harrier, as well as in the AV-8B Harrier IIvariant. Widespread use of thrust vectoring for enhanced maneuverability in Western production-model fighter aircraft didn't occur until the deployment of the Lockheed Martin F-22 Raptor fifth-generation jet fighter in 2005, with its afterburning, 2D thrust-vectoring Pratt & Whitney F119 turbofan. While the Lockheed Martin F-35 Lightning II uses a conventi...

    Other

    Examples of rockets and missiles which use thrust vectoring include both large systems such as the Space Shuttle Solid Rocket Booster (SRB), S-300P (SA-10) surface-to-air missile, UGM-27 Polaris nuclear ballistic missile and RT-23 (SS-24) ballistic missile and smaller battlefield weapons such as Swingfire. The principles of air thrust vectoring have been recently adapted to military sea applications in the form of fast water-jet steering that provide super-agility. Examples are the fast patro...

    Thrust vectoring can convey two main benefits: VTOL/STOL, and higher maneuverability. Aircraft are usually optimized to maximally exploit one benefit, though will gain in the other.

  3. en.wikipedia.org › wiki › Force_IndexForce index - Wikipedia

    Force index. The force index ( FI) is an indicator used in technical analysis to illustrate how strong the actual buying or selling pressure is. High positive values mean there is a strong rising trend, and low values signify a strong downward trend. The FI is calculated by multiplying the difference between the last and previous closing prices ...

  4. In orbital mechanics, low-thrust relative transfer is an orbital maneuver in which a chaser spacecraft covers a specific relative distance relative to the target spacecraft using continuous low-thrust system with specific impulse of the order of 4000-8000s. [1] This is in contrast to conventional impulsive transfers in the orbit which uses ...

  5. Rolls-Royce. First flight. 3 August 1954 (free) Number built. 2. The Rolls-Royce Thrust Measuring Rig (TMR), was a pioneering vertical take-off and landing ( VTOL) aircraft developed by Rolls-Royce in the 1950s. It has the distinction of being "the first jet-lift aircraft to fly anywhere in the world". [1]

  1. 推力計 相關
    廣告
  1. 其他人也搜尋了