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Official Freewing JAS 39 Gripen 80mm EDF Jet

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  • Originally posted by Airguardian View Post
    Gotcha!

    The answer is yes (kinda).

    Hope that helped! :)
    Perfect!

    That was the piece I needed, thank you for taking the time!

    I thought the gyro wasn't as sophisticated as it is. So the easy way to achieve what I want will be to add up elevon without sending that signal to the gyro, thereby the gyro will work to maintain 0deg/s but the elevons will give the aircraft a nose high attitude with stick centered. It will be the same as moving the CG further aft but having full control. Nonetheless it will be a very incremental process to get it to work. Looking forward to this!


    Comment


    • Yep, I have done exactly that on my Eurofighter but I don't use it. The jet reacts better when the normal 'pitch-to-canards' mix is active.

      So, the way I would do this is, have it switchable:

      Normal operation with normal pitching canards (gyro can be turned off separately if it allows such a feature).
      Separate mode with no pitch being fed to the canards' gyro (or rather, center pulse being fed regardless of pitch stick input).

      Start flying with the first and you can try the second. If it doesn't work as expected, go back to the first. Always have a safe and proven plan B, so to speak, and all should be good :)

      Comment


      • Yes, having a proven option to revert to is a must.

        Think I was unclear, but what I was thinking is to have the gyro set up as you describe in pitch connected to the stick input and functioning as it should on a separate channel. On another channel the elevons will also react to the stick input, but on that channel I can feed in some extra, for example 10% up pitch via a slider or a switch. That will give the aircraft a tail low attitude that the gyro will help to keep. It can be that during the deployment of the up elevon, the same signal will be sent to the gyro allowing it to accept the pitch change and as soon as the correct position is set, the extra signal to gyro will be taken away but remain on elevon. All this is definitely doable in OpenTX. Will be tried out at quite some altitude and very small increments...

        Comment


        • I see... yeah, that could work too! :)
          Just be careful with sliders... don't allow them to modify the full range of your surface deflection or prepare to have nasty surprises!

          I would use a safety toggle that enables the slider/pot to modify center point by say, max 10-15%.

          Overdoing this would likely be pretty bad but in small amounts it may give very cool results!

          Comment


          • The first upgrade part...

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            • Originally posted by xviper View Post
              Are you willing to wait a long time? My last Banggood purchase took over 3 months during the pandemic.


              It acually arrived in 5 days! And even more suprising it WORKS! It fits perfectly on the tailpipe of the 80mm Freewing Avanti. Im so impressed I'm buying 2 more.

              Comment


              • Still questions to set up a gyro:

                The gyro sets the elevon mixing !?! The transmitter is set to plane type: “normal”.

                The gyro connects elevator1 and elevator2 servo.
                The gyro cannot connect the canards servos ?!?

                The transmitter does the aileron/elevator to canards mixing ?!? How will that now work with the gyro?!?

                Comment


                • Hi Airguardian,

                  could you please send a wiring picture ?


                  Comment


                  • Originally posted by hirth90 View Post



                    It acually arrived in 5 days! And even more suprising it WORKS! It fits perfectly on the tailpipe of the 80mm Freewing Avanti. Im so impressed I'm buying 2 more.
                    Was the ring or the Eberhard centerburner? Or something else? Links and pics if possible, please

                    Comment


                    • Very low cost AB ring works great and arrived in Europe 5 days after placing the order.


                      Comment


                      • Originally posted by slumi View Post
                        Still questions to set up a gyro:

                        The gyro sets the elevon mixing !?! The transmitter is set to plane type: “normal”.

                        The gyro connects elevator1 and elevator2 servo.
                        The gyro cannot connect the canards servos ?!?

                        The transmitter does the aileron/elevator to canards mixing ?!? How will that now work with the gyro?!?
                        Yes, the typical gyro sets the "wing type", TX set to "normal" (unless you have flaps).
                        Depending on the type of gyro you're using, it's usually each elevon go into ELE and AIL.
                        If you "Y" each canard to each elevon, then you can have the same gyro for them as well (you may need a servo reverser). If you want the canards on a gyro and only want them to act like elevators, then you need a second gyro.

                        Comment


                        • Originally posted by hirth90 View Post
                          Very low cost AB ring works great and arrived in Europe 5 days after placing the order.

                          Is that with the standard "default" shipping or did you pay extra for the "fast" shipping?

                          Comment


                          • Hi folks,

                            MotionRC set the skill level for this plane to “intermediate”.
                            The canard setup seems complex to me, especially if you want to use a gyro.
                            The mirage on the other hand is set to skill level “advanced”.
                            I am here a bit confused.

                            Comment


                            • Originally posted by slumi View Post
                              Still questions to set up a gyro:

                              The gyro sets the elevon mixing !?! The transmitter is set to plane type: “normal”.

                              The gyro connects elevator1 and elevator2 servo.
                              The gyro cannot connect the canards servos ?!?

                              The transmitter does the aileron/elevator to canards mixing ?!? How will that now work with the gyro?!?
                              What XViper said, but I'd be wary of linking canards and elevons to the same gyro. At the very least you would need to cross-Y-wire left canard with right elevon and so on... and right now I can't guarantee that will give you the apropriate correcting directions. I DO NOT RECCOMMEND doing this.

                              Instead, I would use a separate gyro for elevons and canards. Easier to do and allows you to set up different gains for canards and elevons (usually you want more gain on canards because they have a smaller pitching contribution due to a smaller distance to CG).

                              Transmitter just outputs pitch and roll. Mixing has to be made at gyro level when doing this.
                              Read the manual of your gyro. Everything should be detailed in there. If you are using a gyro you must read the instructions and familiarize with its operation. ;)

                              Originally posted by slumi View Post
                              Hi folks,

                              MotionRC set the skill level for this plane to “intermediate”.
                              The canard setup seems complex to me, especially if you want to use a gyro.
                              The mirage on the other hand is set to skill level “advanced”.
                              I am here a bit confused.
                              The Mirage is more twitchy and harder to fly.

                              The mixing is really not that difficult.

                              Just spend some quality time learning your transmitter functions! ;)

                              Comment


                              • Hi Airguardian,

                                thanks a lot for your reply. I hope that the plane has the space for two gyros in parallel.
                                By the way I saw your video with the Euro fighter and the Eagletree Guardian.
                                I use this gyro in all my planes, most self-build delta-wings.
                                So gyro setup is no problem.
                                When using two gyros, you probably need to Y-wire the Mod-cable !?!? Both gyros need to switch to 3D /2D mode simultaneously.

                                Comment


                                • Yes, that would be an option.
                                  I think you could Y-wire the pitch channel too (from rx to pitch input on both elevons and canard gyros) but keep gains separated.
                                  Guardian has been working very well on a few of my jets, it's a real pitty that Eagltree shuts down :'(
                                  Bye, bye Guardians... we'll have to take care of our remaining units!

                                  In any case, using a Guardian just for the canards may be overkill. I will likely use a single axis gyro for that purpose, but the one I use is no longer manufactured so I can't recommend it, sorry!

                                  Maybe you could use the second Guardian for canards AND nozzle if you do the VT nozzle upgrade though, that could make sense (As the canards will likely tolerate the higher gains that the nozzle will demand, and just like the canards, nozzle should be detached from direct pitch trim on the transmitter).
                                  :)

                                  Comment


                                  • Originally posted by slumi View Post
                                    Hi folks,

                                    MotionRC set the skill level for this plane to “intermediate”.
                                    The canard setup seems complex to me, especially if you want to use a gyro.
                                    The mirage on the other hand is set to skill level “advanced”.
                                    I am here a bit confused.
                                    Skill level is probably correct with intermediate, it is the gyro setup that can be advanced if you want it to do advanced stuff. Aren't they flown without gyros in the promotion videos?
                                    If I wanted a gyro for normal stabilisation I would set it up on the elevons and rudder to get all three axis stabilised and with a double Y (?) from the elevator RX channel prior to gyro, to the canards. The TX being setup as a standard airplane with normal tail, which is covered in the gyro-videos if you're getting a gyro from Motion. Then the gyro would have to be setup as an airplane with elevons also explained in gyro-vids.
                                    So far I have only used a gyro in my 70mm F16, but it was removed since I didn't spend enough time setting it up and it wasn't really helping and the plane was doing alright anyway. On the Gripen I will put a gyro on the canards for that advanced stuff and having them move "correctly". This time I will take my time and do my homework (thanks Airguardian ).

                                    On the same topic: Having the roll mixed on the canards will look awesome on the bench and at the field, but not so much aerodynamically in the air. It will probably just disturb the flow over the wing without contributing to much to the roll rate. This is just a well educated guess, but in slow flight and high alpha, introducing a roll left input could result in a roll to the right. For this to happen, the CG need to be far aft or you won't get that high alpha anyway. But maybe that is for another discussion about energised flow and vortices over the wing.

                                    The Mirage is a small delta-plane with large engine, giving it extreme performance in many ways. With the larger wing and size, the Gripen will be easier on the easy end but probably as nimble and difficult at the advanced end. The major drawback with the Mirage is that it gets very small very quick, but it still flies great without a gyro, might even be better if I had one in it, but I have not felt the need yet.

                                    It will be alright with or without gyro.

                                    Comment


                                    • I write too slow! and assume too much, sorry slumi

                                      Comment


                                      • Thanks for all your replies.
                                        I always use a gyro to have a rescue function. In addition the Eagletree Guardian is really a good gyro. I permanently use Guardian’s 3D mode. Although Eagletree systems closes , I still have gyros in reserve or take it from unused older planes.

                                        MotionRC most uses the Admiral SP (copy of Lemon StabPlus) which is not a 100% reliable as Eagletree’s.
                                        Also the HobbyEagle A3 Super 3 has a weekness, when using auto level as a rescue.

                                        MotionRC has good setup videos on YouTube, which I watched for the Gripen.
                                        Basically the canards work exactly as the two elevon servos.
                                        For the elevon servos you have your view on the plane from the rear (pilots view). For the canards you have your view from the front (opposite pilots view).
                                        In that sense the elevator servos work exactly as the canards.
                                        So a single gyro probably will work.

                                        Comment


                                        • Originally posted by Aros View Post
                                          it would be really nice if those of us who pre-ordered the Gripen could also pre-order the TV so we could install it during the initial assembly.

                                          Comment

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