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Thread: Would like to see:

  1. #11
    Senior Member
    Join Date
    Mar 2010
    Location
    gilford, nh
    Posts
    335
    Yes perhaps also Vr-rotation and Vg(best glide)
    Alan

  2. #12
    Yes perhaps also Vr-rotation and Vg(best glide)
    Good idea!

  3. #13
    How about Vapp or Vref? Of course, maybe a little programming to have the screen use Vr for the takeoff and Vref for the landing. "if after start up airspeed > 75 kts" then do not display Vr. "if airspeed is > 75kts after Vr is removed then display Vref" (just winging it here guys....I'll let the pros figure out a better way).

  4. #14
    Quote Originally Posted by Mastro View Post
    (just winging it here guys....I'll let the pros figure out a better way).
    How about using AOA?

    You all do know that Vg(best glide) and Vapp(approach) change with current aircraft weight and are constant with AOA?
    • An aircraft in the landing configuration will stall at the same AOA regardless of airspeed, fuel weight, payload, ā€œGā€ loading, bank angle, and turbulence.
    • If the critical AOA is constant during these different conditions then the optimum AOA for an approach is also constant.
    • All approaches are flown at a fixed AOA.
    • The L/D ratio is not a function of airspeed or weight. A lightly loaded aircraft will have the same L/D as when heavier except that it will have a slower descent rate and a slower forward speed.
    • Ignoring propeller effects, the best L/D occurs at a fixed AOA.

    Does Vr really apply to an RV?
    Rob Hickman
    Advanced Flight Systems Inc.

  5. #15
    I agree with you Rob - V1 is critical for airliners as it is the decision speed at which a takeoff is rejected or continued in case of engine failure considering weight, runway length and atmospheric conditions. Vr is the rotation speed which after a normal rotation will give you the recommended margin to V2 which is the engine out climbout speed. These speeds are calculated for every takeoff and then, depending on aircraft type, either set by means of bugs on an analog airspeed indicator or entered into the FMS which will display it on the EFIS speed band. It has no relevance for single engine GA aircraft and even anyone using it on a multi-engined aircraft would have to somehow calculate it and enter it for every takeoff.
    Optimum speeds for minimum drag, Vapp etc are generated by the angle of attack vanes and are depicted by symbols on the EFIS speed band on most modern airliners. I'm not sure how easy it would be to make your AOA system do this and show the speed corresponding to the desired AOA but it may be worth thinking about and doing. Of course the symbol would move on the speed band in a turn for instance when the g changes - we see this in airline cockpits too. The next best thing to the very expensive systems built into Airliners is of course the Advanced AOA indication so you guys may want to learn to use it if you don't already do so as it does supply very valuable information corrected for weight and g force.

  6. #16
    Gents, this is very useful information, thank you.

  7. #17
    Quote Originally Posted by Rob Hickman View Post
    How about using AOA?
    You're right Rob, the Vr's, V2's, Vref's don't apply to us and the AOA function does and that's why I purchased that option which I love. But, since I do like bells and whistles would it makes sense to put a symbol on the airspeed tape indicating "best lift over drag" ?

    This is kind of related to the other discussion on using a tape coming up from the bottom to indicate your stall is coming or a tape coming from the top indicated buffet is coming and something in the L/D tied to the AOA system may be cool to have.

    When I said leave it to the pros - I do think you guys run with great ideas and build on others such as ours on the forum. I figure this forum is the best place to "Brain Storm" to keep AFS the best system out there!

  8. #18
    How about just using the speed bug which you can set to any value you like or not clutter up the display if you don't want it?

  9. #19
    Recognizing that the 4500 is just about at the end of its resources, small incremental improvements that don't over tax what's left of those resouces would go a long way to keeping the installed base happy. To that end, I would like to suggest a feature that would hopefully not over tax either your programmer's time or the 4500.

    Shock Cooling Alarm: If the CHT's are decreasing at > X (30) degrees/minute, then display alarm condition.

    Rob, thanks for a great product and congratulations on ATS.

    Nick

  10. #20
    Junior Member
    Join Date
    Mar 2010
    Location
    Sydney, Australia
    Posts
    20

    Hwy in the sky

    For the 4500 series, I can recall comment that AFS is working on having the Hwy in the sky boxes follow a vertical profile from the aircraft's current altitude rather than the boxes disappearing above or below when you wind the ALT bug up or down. How is this progressing?

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