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Light Stealth Aircraft (LSA) - Concept Aircraft

Discussion in 'Indian Air Force' started by randomradio, Mar 19, 2016.

  1. HariPrasad

    HariPrasad Lieutenant FULL MEMBER

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    But you were saying that HTPE 25 varient of 35 KN dry will weigh at the most 500 KG. So where is the weight increase on account of twine engine configuration?
     
  2. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    PARIKRAMA likes this.
  3. Flyboy!

    Flyboy! Lieutenant FULL MEMBER

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    As a safe option, is there a need to seriously consider the ge 404 if other engines don't make the cut?
     
  4. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    No, that will make LSA grossly underpowered. If we are not going to have HTFE40 with afterburner, we will stick to single engine design.
     
  5. shaktimaan

    shaktimaan Lieutenant FULL MEMBER

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    So, u r thinking of using htfe engine but what about avionics as european consortium reluctant to provide it ...and what about ram coating ???
     
  6. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    HAL recently issued RFP for AESA radar and integrated EW system for LCA with rights to sell them to any one. I always has that option available to me.
     
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  7. randomradio

    randomradio Mod Staff Member MODERATOR

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    F-125?
     
  8. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    That is heavier compared to HTFE-40. Twin F125X will add more weight to the aircraft and spoil its fuel fraction, wingloading, span loading and power loading. In short, we will lose out majorly on performance.
     
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  9. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    You have no clue of what is the level of my knowledge of aerodynamics, aerostructures and Fluid dynamics. If you go thru the LSA thread, you will see the CFD analysis done for that aircraft. That has not been done by ADA or HAL but myself. So much so that I designed the supersonic supercritical air foil for LSA myself, did its CFD analysis, corrected the boundary layer control, separation point, camber, CD & CL figures, revised the air foil to get the performance I wanted from it. You are a child with zero knowledge on this subject. You too seem to have been fooled by my basic education degree of Just B. Sc (Physics) and my back ground of a Fighter Pilot.
     
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  10. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    @Vyom, I openly challenge you, I will post some of the CFD data here. Please interpret that for all of us. let me see what is your level of knowledge on this subject. You have already proven yourself to be a flop regarding nuke bombs.
     
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  11. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    @Himanshu Pandey, this is the thread. Pls go thru it in detail. This has all the shades from ridicule to appreciation to outright rejection.
     
  12. Himanshu Pandey

    Himanshu Pandey Don't get mad, get even. STAR MEMBER

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    102 pages.. I am damned.
     
  13. Vyom

    Vyom Captain GEO STRATEGIC ANALYST

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    In aircraft instruments, gyros are used in attitude, compass and turn coordinators. These instruments contain a wheel or rotor rotating at a high RPM which gives it two important properties: rigidity and precession. The rotor or gyro can be electrically or vacuum / pressure driven by a special pump on the engine.

    Construction wise the gyro is fixed in the instrument by rings or gimbals and these give the gyro certain motions of freedom. It is these motions or movement in each planes which allow for certain characteristics used in these instruments.

    Pilots flying under VMC will normally only rely on these instrument when getting out of IMC situations. Keep in mind that to be proficient in flying on instruments you will need regular training with a safety pilot, aka flying under the hood.
    Without being current on instruments, most if not all VFR pilots, will probably crash when attempting to fly in IMC conditions due to the lack of experience and training.

    Rigidity & Precession

    These two properties are unique to a rotating mass. Keep on reading below for an explanation of how they work and their application in aircraft instruments.

    Rigidity
    Whilst small, the rotor of a gyroscopic instrument must rotate at a very high RPM. Giving them inertia, also called rigidity and the rotor maintains this alignment to a fixed point in space. This basically happens to every rotating object: wheel, propeller etc.. For example: this rigidity gives the moving bicycle its stability preventing it from falling over while riding it.

    A number of factors have their influence on rigidity: the mass of the rotor, its RPM or angular velocity and finally the distance of the mass to the axis of rotation. The larger the distance the greater the rigidity with equal rotational speed. Again, a bike has large wheels and it can rotate slowly to obtain enough stability for the rider to maintain balance.

    Precession
    When you apply a force to a point around the spinning rim of the gyro, the rotor will tilt as if the force was 90° further in the direction of motion as shown in the image. This apparent displacement of the force is called precession.

    The amount of precession depends on the following factors: strength and direction of the force applied, the amount of inertia of the gyro (mass concentration on the rim), diameter and the RPM or rotational velocity of the gyro.

    To conclude: the rate of precession in a free gyro is directly proportional to strength of the force and inversely proportional to the RPM and the moment of inertia. Thus the more mass and RPM a gyro has the more stable it is and maintain its position to a fixed point in space.

    Gimbal rings
    The gyro rotor is held in place by rings or better known as gimbal rings. These allow for freedom of motion in three dimensional planes as required by the instruments of the aircraft. Not all instruments will need all the planes of movement at the same time, this depends on their function, see the next pages.

    Planes of movement
    There are three possible motions for a gyroscope: the plane of rotation of the gyro; the plane of applied force and as a result: the plane of precession. Please refer to the image above for more detail and three dimensional view.

    Gyro models
    Depending on how you setup or mount the gyro in the gimbal rings it will have number of planes the gyro can move in, each useful to the pilot in different instruments. Below you will find a list of possible installations:

    • Rate gyro can move in one plane (not the plane of rotation) and the movement in the third plane is used to measure the precession. You will see this type of gyro in a Turn Coordinator or Turn and Bank indicator (old models).
    • Tied gyro moves in all three planes but kept in one plane by an outside force, usually air jets in case of the Direction Indicator (Gyro compass)
    • Earth gyro has freedom of movement in all three planes but is held in one plane by Earths gravity. You will find this gyro in an Attitude Indicator.
    • Space Gyro moves in all three planes and is stabilized to a fixed point in space. You will apparently see this gyro move due to the Earths rotation while in fact its not moving at all, space wise.
    These gyro instruments are delicate pieces of equipment and will need proper care and handling by maintaining the vacuum system to very high standards. Only then can they be relied upon in actual instrument conditions by the pilot where basic seat of the pants flying often fails and the results can be disastrous.

    Also Recommended read :
    Airplane Stability and Control: A History of the Technologies that Made Aviation Possible
    Book by E. Eugene Larrabee and Malcolm J. Abzug
     
  14. Vyom

    Vyom Captain GEO STRATEGIC ANALYST

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    I will take this aircraft seriously the day it gets even its first prototype. Or a scale model wind tunnel test.

    Rest I don't wish to engage on this absurdity, cuz it simply drives my temper through the roof. I wish to keep my sanity.
     
  15. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Gyroscope and stability are two very different things. Stability is of two types-Static and Dynamic. These are in three planes of motion-Longitudinal, lateral and vertical. Gyroscopes have nothing to do with stability. There is no word called gyroscopic stability w.r.t aerodynamics. Pls get your fundas clear. You have zero knowledge of aerodynamics and you want to debate with me on this topic which I have lived for last 34yrs and also adjudged "best in ground Subjects" twice in my service career.
     
    Riley Amos likes this.

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