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  • Pitch curve questions

    Bit of a long post ... apologies ...

    I'm looking for some advice on beginner's pitch curves. I'm flying a Trex 550e fbl with one of the new Scorpion 50V ESCs (the one with a good governor, apparently, unlike the previous Scorpion LV ESCs) and the stock Align motor.

    The machine is set up with +12/-12 degrees of pitch (per the mini vbar set-up process), and I'm looking for some pitch curves to tame things down. I'm flying with the governor switched on.

    A very capable friend has set up my Tx with straightline (excluding point 1 which is 0%) throttle curves of 70% in normal mode, 75% in Idle 1 and 80% in Idle 2 (although I'm only using Normal mode just now). My pitch curve across all three modes is 23,39,60,78,95, which equates to -6½ ,-2½ , +2½, +6½, +11 degrees of pitch.

    I've been learning to hover tail in with that pitch curve, and doing OK, but I feel that the -6½ is too much for me at the moment. I've bounced a few landings, but the boom and everything else is still intact ... so far! Certainly even just spooling up, the carbon rods on my training gear are being pretty bent with the negative pitch.

    I'll check with my friend, but I understood his thinking was along the lines of "its best for learning to keep a linear pitch curve across the range of stick movement (hence these points, and also the recommendation not to use expo), and to use a curve as close as to what I would use as I progress in the hobby". I think, however, that he might have thought my mechanical set-up was giving me -10/+10 degrees of pitch, which would equate to a bit more reasonable -5½, -2, +2, +5½, +9 degrees of pitch.

    Anyway, a long story to ask the following questions ....

    - Is 70% governed throttle a good Normal level? Seems fine to me when hovering, but what would I know!
    - Because I'm running governed head speed, I don't need to be switching flight modes when I start in forward flight, right?
    - Throttle percent increases across the flight modes – that is increasing headspeed, right? That makes it more agile? I've read a faster motor is more efficient, but I presume it willstill reduce flight times if I up the head speed? I'm currently getting a wonderful 8½ minutes on my 30C Turnigy 5Ah batteries
    - Would it be a better option to use a gentler pitch curve in Normal mode, say -2 or -3 degrees at low stick for my hovering, and then switch to something more like my existing curve in Idle 1 which I could switch to when doing forward flight?

    All thoughts and suggested Newbie pitch curves that will stand me in good stead as I progress would be much appreciated.

    Many thanks.
    Last edited by alistair.howie; 06-07-2011, 08:14 PM.

  • #2
    I still use a different pitch curve from normal to idle up .. from centre stick up everything it the same , its below centre stick that I changed it .. You could always change the pitch curve to say some like 35,40,50,75,100 normal and then idle up 0,25,50,75,100...50 deing 0 degrees What you are trying to do is make it as nice below centre stick so you dont ram it into the ground . You could always just get it so its pitch range is -2 to say the full +12 ... the choice is yours .. Looks like its the pitch range below centre stick thats giving you problems .. Just alter it until it feels comfy ....As for the not using expo... its there for a reason and TBH I still use it and so do alot of other pilots .. Try putting -20 if futaba and + 20 if spekky and try that .. Hope this helps
    As for the throttle curves I do not run elec so cannot help you in that ....
    Knight 3D
    http://northeast3d.talkheli.co.uk/
    http://www.lindensflyingclub.co.uk/

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    • #3
      Hi. I run 50,75,100 from centre upwards on normal and both stunt settings. Below centre for normal I use 40,45 and 0,25 for st1&2. The idea is that on normal you get some fairly tame negative and avoids ramming into the ground on spool up. Using these settings avoids big jumps (and surprises) when switching between modes.
      Steve
      -------

      Trex 500 ESP
      Trex 450 Pro
      Trex 250
      Blade 130 x (2)
      Brushless nano

      Comment


      • #4
        Originally posted by vtrnutter View Post
        Hi. I run 50,75,100 from centre upwards on normal and both stunt settings. Below centre for normal I use 40,45 and 0,25 for st1&2. The idea is that on normal you get some fairly tame negative and avoids ramming into the ground on spool up. Using these settings avoids big jumps (and surprises) when switching between modes.
        +1 to vtrnutters settings

        nice and gentle for hovering and doesnt slam into the ground too easily, idle up gives a bit more negative when needed
        Blade 130x
        Align Trex 150 DFC
        Align Trex 500
        Gaui 550 Hurricane
        HK 600 GT
        DJI Phantom 3 Advanced
        Phoenix sim

        I have a perfect record with helicopter flight...I have never left one up there!

        Comment


        • #5
          Settings on my 600E & 550E from a start up were:-
          Pitch Curve
          50, 50, 50, 75, 100
          0, 25. 50, 75, 100
          0, 25, 50, 75, 100
          Throttle Curve
          0, 40, 60, 80, 100
          80, 80, 80, 80, 80
          100, 100, 100, 100
          Been there and done that, but never stop learning.
          Now too many Helis to mention?

          Comment


          • #6
            Originally posted by vtrnutter View Post
            Hi. I run 50,75,100 from centre upwards on normal and both stunt settings. Below centre for normal I use 40,45 and 0,25 for st1&2. The idea is that on normal you get some fairly tame negative and avoids ramming into the ground on spool up. Using these settings avoids big jumps (and surprises) when switching between modes.
            Thanks. So what do 40 and 45 relate to in terms of pitch? Also, do you run any expo, or would you recommend it for a beginner? If so, how much. Also, re expo, how come I can't get expo on the collective stick? My DX8, if I remember correctly from last night, gives me expo potential on aileron, elevator and rudder ... but not collective?

            Comment


            • #7
              Originally posted by johnsandywhite View Post
              Settings on my 600E & 550E from a start up were:-
              Pitch Curve
              50, 50, 50, 75, 100
              0, 25. 50, 75, 100
              0, 25, 50, 75, 100
              Throttle Curve
              0, 40, 60, 80, 100
              80, 80, 80, 80, 80
              100, 100, 100, 100
              I understand your Idle 1 and 2 curves, but can you explain the below half stick part of your normal curve? What pitch does 50% relate to? Thx

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              • #8
                Originally posted by alistair.howie View Post
                I understand your Idle 1 and 2 curves, but can you explain the below half stick part of your normal curve? What pitch does 50% relate to? Thx
                This was something I picked up from another Forum for a beginners Normal flight to give around -2 max. I now have 0, 25, 50, 75, 100 on all modes. The original setting was to allow for a gentle take off and for me it worked. Having only hovered, piro'd and nosed in with a Twister 3D Storm and no idle up, I was taking no chances with the Trex's. I am now starting to chuck them about after only 2 weeks of flying at a FIELD and NOT on a Campsite.

                Been there and done that, but never stop learning.
                Now too many Helis to mention?

                Comment


                • #9
                  Been there and done that, but never stop learning.
                  Now too many Helis to mention?

                  Comment


                  • #10
                    This is just a little bit I learned when starting this hobby, don't set your negative to a not-very-negative setting. All the beginners guides say something like -2 or -3 degrees so you don't drive it into the ground when you shut the throttle. There is a big downside to this thinking which caused me several crashes in the beginning and that is wind. Unless you are flying in the most still conditions a bit of wind will cause a bit of lift, add a bit of motion to the heli and the lift will be greater and with only a little bit of negative pitch the only way to get it down will be to reduce headspeed; this is what I did until it just fell out of the sky. Since then I have set my negative to -6 and remembered not to ever slam the throttle to zero; I haven't crashed since.

                    Cheers

                    Martin
                    Never happy, merely less depressed.

                    Blade mSR
                    Blade 400
                    Supercub LP
                    Sukhoi SU-26
                    Yanagisawa Tenor Sax (doesn't fly well though)

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                    • #11
                      Originally posted by alistair.howie View Post
                      Thanks. So what do 40 and 45 relate to in terms of pitch? Also, do you run any expo, or would you recommend it for a beginner? If so, how much. Also, re expo, how come I can't get expo on the collective stick? My DX8, if I remember correctly from last night, gives me expo potential on aileron, elevator and rudder ... but not collective?
                      Hi. I have not measured it. My 0 and 100 points are -12 and +12 respectively so guessing that 40 is around -2.5 degrees.
                      Steve
                      -------

                      Trex 500 ESP
                      Trex 450 Pro
                      Trex 250
                      Blade 130 x (2)
                      Brushless nano

                      Comment


                      • #12
                        Originally posted by vtrnutter View Post
                        Hi. I have not measured it. My 0 and 100 points are -12 and +12 respectively so guessing that 40 is around -2.5 degrees.
                        Thanks ... 40% will be -2.4 and 45 -1.2.

                        I was playing about on Phoenix last night and liked the following normal curve with 15% expo, so I think I'll give that a try when the weather improves ...

                        35,47,61,75,90 ... which on +/- 12 degrees range equates to about -3.5, -1, 2.5, 6, 9.5.

                        No reason why mid stick MUST be zero pitch, right?

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                        • #13
                          i have neer touch my pitch curves i just leave it the way it is in the radio and manage my own pitch, i think that way i/u can learn better how to manage ur pitch
                          Do what u do best


                          T rex 700LE beast x radix 710 fbl blades
                          T rex 700LE stock radix 710 SB
                          T rex 600LE beast x radix 600 fbl blades
                          T rex 550E beast x align blades
                          DX7 and DX8
                          Phoenix sim
                          And plenty of spare parts

                          Comment


                          • #14
                            Originally posted by stunks View Post
                            i have neer touch my pitch curves i just leave it the way it is in the radio and manage my own pitch, i think that way i/u can learn better how to manage ur pitch
                            So you mean you run 0,25,50,75,100 on, what +/- 10,11 or 12 degrees of pitch?

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                            • #15
                              Originally posted by alistair.howie View Post
                              So you mean you run 0,25,50,75,100 on, what +/- 10,11 or 12 degrees of pitch?

                              yes thats what am running and a using ATM 12 deg+/-
                              Do what u do best


                              T rex 700LE beast x radix 710 fbl blades
                              T rex 700LE stock radix 710 SB
                              T rex 600LE beast x radix 600 fbl blades
                              T rex 550E beast x align blades
                              DX7 and DX8
                              Phoenix sim
                              And plenty of spare parts

                              Comment

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