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Thread: Cessna 170B IFR

  1. #21

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    Jul 2011
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    e Daniel , no matter what the regs will let you get away with, flying real ifr that is in imc when you cannot see out of the plane to either the ground or the horizon is serious situation. If you disagree, get a CFI or good pilot friend and go up in a fully eqiuiped plane, preferably on a grey day or at night, put on a hood and then cover the att indicator and see how long you can fly safely. And can you do it with turns, climbs, descents and better yet some turbulence. And remember youll also have to navigate in real imc, that is turn radio channels or vors or gps or whatever, not the same as sitting at a console. And you have a basic plane probably without and autopilot and you are a new student at this. Be careful.

  2. #22

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    Quote Originally Posted by Mike M View Post
    ...The FAA and EAA and industry have come up with ways to go glass, even all glass, without gyroscopes - and still have backup...
    Minor nit - the glass cockpit EFIS's that have ADHRS systems DO have gyroscopes, just like your iPhone does - they're just electronic, not mechanical spinny things. They're rate gyros, for the most part, so require a lot of stabilization, but they ARE gyroscopic.

    And most EFIS's have gyroscopic pitch and bank, as well as a directional gyro AND a gyro based rate of turn indicator, all built into the ADHRS. So you get everything in one package.

  3. #23
    FlyingRon's Avatar
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    Actually, iphone (and many of the electronic flight units) have accelerometers. They are not "gyroscopic" in the least. They perform the same function but without using gyroscopic principals.

  4. #24

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    Quote Originally Posted by FlyingRon View Post
    Actually, iphone (and many of the electronic flight units) have accelerometers.
    That is very true.

    Quote Originally Posted by FlyingRon View Post
    They are not "gyroscopic" in the least.
    That is very true as well.

    Quote Originally Posted by FlyingRon View Post
    They perform the same function but without using gyroscopic principals.
    Well, you should inform Apple of this. Their spec pages at:

    https://www.apple.com/iphone-6s/specs/
    https://www.apple.com/iphone-7/specs/
    https://www.apple.com/iphone-8/specs/
    https://www.apple.com/iphone-x/specs/

    show 3 axis gyros as well as accelerometers. I don't know which iPhone was the first to have gyros, but it was a number of years ago. My iPhone 6 certainly has gyros as well.

    Accelerometers CANNOT perform the same function as gyroscopes, which is why people use gyroscopes. Your slip/skid indicator is an directional accelerometer - the ball points in the direction of airplane vertical axis acceleration. Even if it had a number on it to indicate the "G" loading in the direction of the acceleration, it would tell you nothing about the orientation of your aircraft in space. You could be upside down in the top of a loop pulling one G at a constant speed and your three accelerometers would believe that everything was exactly the same as if you were in straight and level flight at 1 G. This would obviously not be useful for orientation information - only a gyroscope can provide that. A 1.5 G spiral dive would be another situation where accelerometers would be useless for orientation information.

    As I said before, the gyros in the ADHRS and iphones (and some android phones) are solid state electronic devices, probably with small vibrating cantilever beams (at least that's what I designed in one of the first ones in 1981) - see:

    https://en.wikipedia.org/wiki/Vibrat...ture_gyroscope

    under "piezo electric gyroscope". By measuring and integrating the measurements of the vibration of the beams, one can get orientation information that one cannot get from an accelerometer.

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