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JLang

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About JLang

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  1. 3 Steps to determine Vx Best angle of climb.

    Right -- any reason why Vy for best rate should not always be speed for best glide, and Vx for best angle should always be speed for minimum sink, for any airplane?
  2. The end result is that AFTER the additional lift and drag and change in angle of attack is combined, you get back to steady state. Weight does not change. Lift does, and if nothing else changed other than adding flaps, then you would start a climb. However, usually airspeed decreases, with additional drag, and then the lower lift with the lower airspeed goes back to balancing the weight. This is from your own post: "Clean configuration does give best speed, obviously, due to reduced drag, and should also give best rate for the same reason... but not necessarily best angle, because the extra lift the flaps provide may add more vertical speed than you lose from the additional drag, especially at lower speed (drag increases with the square of airspeed, remember)"
  3. 3 Steps to determine Vx Best angle of climb.

    Andy, I believe we touched on this on another topic, but it's my belief/guesstimate, based on interpolating info from both the CTSW and CTLS documentation (what little there is) that CTSW Vy (-6) is about 83kt and Vy (15) is 63kt, at gross weight. If I reason correctly, Vy should be close to if not exactly best glide, and 78kt should be right at Vy for your typical, less-than-gross weight, so that makes sense. Out of curiosity, did you try 15 flaps at something less than 63kts, assuming you were less than gross weight? I would expect the same result, though maybe less dramatic? Related to this, I'm thinking that if the goal was not max glide distance, but to maximize time aloft -- say, if the field was made, but to gain extra time to restart, make radio calls, etc. -- then flaps at 15 and ~63kt would be more suitable, right?
  4. At the same speed or angle of attack, lift is greater with flaps. Adding flaps adds lift. After adding flaps, steady state will return ("goes back to where it was"), but only at a different attitude/power/airspeed configuration. Yes, at steady state lift = weight, but that is not saying the same thing.
  5. To the topic at hand, the important point I was trying to make is that lift is not the same with all flap settings, steady state or not. The way I work through it, if you are flying at steady state, either in level flight at constant speed, or in a stabilized climb (or descent), and you change flaps, then three things happen, all of which momentarily deviate from steady state: change in lift, change in drag, and change in angle of attack. Depending on how/if we adjust control input, we'll end up back to steady state, but only with a different combination of climb, attitude, and airspeed.
  6. So by stating that "I seldom use Vx" you meant "everybody else but me seldom uses Vx." So yes, I guess I didn't read you correctly. Lift is precisely equal to weight with different flaps ONLY at steady state, and then only at very different speeds. Climbing is not steady state. How do you explain lower stall speed and lower liftoff speed with flaps if lift is the same as with -6? You still have not answered what speeds you assume or have determined for Vx and Vy.
  7. I have also stayed out of the fray due to time constraints, but I think here you proved the point made earlier: that you are confusing Vx and Vy. You have stated that you use -6 to achieve best angle, and perform climbouts this way: take off with 15, then clean up and climb with -6 to achieve best angle. How can you do this if you don't know Vx for -6, and "seldom use" it? If you believe -6 achieves best angle, should you not also use Vx for -6 during your frequent canyon climb maneuvers? Also, this point has been made before, but lift is NOT constant for all flap settings. Question: why do flaps at 15 result in liftoff at lower speed than -6, or 0? For your example with glide settings, what speeds are you using for -6, and 0, and 15?
  8. Climbing at -6 degrees vs 0 degrees?

    I agree with WmInce, I think you are confusing Vy and Vx. Your sketch even mixes them up, since you show Vy when discussing clearing an obstacle. Also, lift is not constant between flap configurations. More flaps = more lift. This is why liftoff is sooner with flaps. Of course, drag is also increased, but the point that I think you are missing is that for best angle, at Vx, this is beneficial.
  9. Back to Yosemite - smoky morning - normal lens

    Wow, amazing photos. Does the smoke have the same ethereal blue tint with the naked eye?
  10. Climb speeds

    That makes sense since you are solo more often than not, right? Since book V speeds are at gross, a lighter weight means slower Vy, so 78-80kts well under gross seems to match ~83kts at full weight. I should have clarified my Q as Vy "by the book" or at gross. My experience is best rate at ~83kts gross and ~80 solo w/ 20gal.
  11. Climb speeds

    This may be splitting hairs, but this is right on top of Vy for 0 flaps, which is listed as 78kts. Wouldn't you expect a greater difference? FWIW, this is published for the CTLS, and Vy for -6 is 5kts greater than for 0deg. Right or wrong, I use 83-84kts for Vy for -6, though I usually do more of a cruise climb at 95-100kts above TPA. Of course, this is starting at much lower altitudes than Ed flies (my field is 800').
  12. Climb speeds

    What are you assuming is Vy for -6 flaps?
  13. Flap light in the flap setup display

    I am far from an expert, and your CTLS display looks a bit different than on my CTSW, but according to my Operating Instructions, the upper right LED indicates "maximum up deflection." In the instructions it describes this when operating the flaps manually (rotating the control to the left) to know when the max up position is reached.
  14. "Climbs steeper," or clearing an obstacle, means angle, not rate. Therefore Vx, not Vy. This goes back to my skepticism in this and the other related thread regarding the contention that best angle will always be with least flaps on all aircraft, even those with negative flaps like the CT. Towards the goal of reaching best angle (not rate), at some configuration change that results in less drag, the accompanying decrease in lift and increasing ground speed -- which reduces best angle, everything else being equal -- leads to worse (shallower) climb angle.
  15. Climbing at -6 degrees vs 0 degrees?

    Higher speed is definitely a negative for best angle. The ideal is a helicopter taking off vertically, with zero forward speed.
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