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Official Freewing JAS 39 Gripen 80mm EDF Jet

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  • Airguardian
    replied
    Originally posted by 4923crew View Post
    As I tested various options on this gripen, there is no need for a gyro.
    No one said gyros were 'needed' as such, now, did any?

    That said, if you want to make the best out of it, it is not a bad idea. The reasons have been covered quite in detail already.

    Originally posted by HaroldAnderson View Post
    On those calm days the Gripen is super smooth without gyro on, at least it feels that way to me.
    Gyros helping with wind gusts (for me) is a nice second derivative of having them installed but not the main reason I do install them to begin with so... ;)


    Leave a comment:


  • Airguardian
    replied
    Flying with smoke is terribly addicting.

    You have been warned!



    Leave a comment:


  • FlyBoy90803
    replied
    Originally posted by kallend View Post

    Follow up with more details.

    This is how I have been flying it.

    AR8360T receiver set up for elevons with AS3X on the elevons. Pitch input also sent to channels 6 and 7 which I have previously used for unstabilized canards with 7 reversed to get both canards moving in same direction.

    Adding gyro to the canards for pitch only:

    I used the A3Pro because it allows the gains of the three axes to be set independently. (Can't do this with the A3L)

    Gyro settings:

    Normal mode, elevon/flying wing, orientation flat upright. Set aileron gain to zero, elevator to something non zero, rudder gain irrelevant.

    Pitch output from receiver (Ch6) to gyro elevator input. Nothing to rudder. *Temporary* 1.5mS (neutral) input to aileron input (not sure if needed but didn't hurt) **

    Gyro "Aileron" and "elevator" outputs to left and right canards. "Rudder" output not connected.

    A MIRACLE HAPPENED! Everything worked in the correct direction first time. The canards still respond correctly to elevator stick input, move in the correct direction in response to a pitch change, and do not respond at all to roll.

    ** I don't know whether an input to the "aileron" on the gyro is needed. It flashes a red light if nothing is connected there but everything still seems to work OK. However, leaving a input in an undefined state is not good practice*** and I now have a spare channel (Ch7) so I'm setting that to 1.5mS fixed and leaving it connected.

    *** A3Pro manual specifically states that the rudder input need not be connected for an elevon/flying wing configuration.
    I've gotten to sort of the same conclusion, I am running the AR8360T and have my elevon, rudder set with gyro. Ran a Y to my canards into my A3pro, then to my open aux 7 on AR8360T and ran Mod wire to Aux 8 port. Im getting a slow flashing red light. But my gyro direction works perfect on my canards and normal stick input for canard movement to match my elevons. However I have not figured out how to get my mod channel to work so I can switch gyro on and off. But if I use the pots on the gyro itself I can turn off and slowly turn up gyro gain and seems to work fine. Although have not flow yet (Looks great on work bench). I am still playing with it to see if I dare fly it.

    I may resort back to just having one gyro AR8360T and leaving my canards un stabilized.

    Leave a comment:


  • kallend
    replied
    Originally posted by kallend View Post


    Tested it on the bench with an A3Pro. It works. Needs a bit of fiddling to get everything moving in the right direction. It does solve the "invert servo" problem.
    Follow up with more details.

    This is how I have been flying it.

    AR8360T receiver set up for elevons with AS3X on the elevons. Pitch input also sent to channels 6 and 7 which I have previously used for unstabilized canards with 7 reversed to get both canards moving in same direction.

    Adding gyro to the canards for pitch only:

    I used the A3Pro because it allows the gains of the three axes to be set independently. (Can't do this with the A3L)

    Gyro settings:

    Normal mode, elevon/flying wing, orientation flat upright. Set aileron gain to zero, elevator to something non zero, rudder gain irrelevant.

    Pitch output from receiver (Ch6) to gyro elevator input. Nothing to rudder. *Temporary* 1.5mS (neutral) input to aileron input (not sure if needed but didn't hurt) **

    Gyro "Aileron" and "elevator" outputs to left and right canards. "Rudder" output not connected.

    A MIRACLE HAPPENED! Everything worked in the correct direction first time. The canards still respond correctly to elevator stick input, move in the correct direction in response to a pitch change, and do not respond at all to roll.

    ** I don't know whether an input to the "aileron" on the gyro is needed. It flashes a red light if nothing is connected there but everything still seems to work OK. However, leaving a input in an undefined state is not good practice*** and I now have a spare channel (Ch7) so I'm setting that to 1.5mS fixed and leaving it connected.

    *** A3Pro manual specifically states that the rudder input need not be connected for an elevon/flying wing configuration.

    Leave a comment:


  • HaroldAnderson
    replied
    Originally posted by janmb View Post

    This!

    A little bit of me dies whenever I read someone talking about whether or not a model NEEDS a gyro.

    Your car doesn't NEED power steering or cruise control either, but it is damn nice to have anyway. It is virtually never about need.
    Sometimes I really feel like I *need* a gyro but that's only when I decide to fly on a questionable day and the wind is blowing 12 mph gusting to 20 mph. We don't get too many low wind days of under in Oklahoma so almost every plane I own has a gyro. On those calm days the Gripen is super smooth without gyro on, at least it feels that way to me.

    Leave a comment:


  • janmb
    replied
    Originally posted by kallend View Post
    I've yet to find a R/C plane that NEEDED a gyro. Almost all fly better and smoother, especially in gusty winds, with a gyro.
    This!

    A little bit of me dies whenever I read someone talking about whether or not a model NEEDS a gyro.

    Your car doesn't NEED power steering or cruise control either, but it is damn nice to have anyway. It is virtually never about need.

    Leave a comment:


  • kallend
    replied
    Originally posted by Airguardian View Post
    Now that's an interesting idea!

    Would solve the problem of needing to invert a servo direction.

    Tested it on the bench with an A3Pro. It works. Needs a bit of fiddling to get everything moving in the right direction. It does solve the "invert servo" problem.

    Leave a comment:


  • kallend
    replied
    Originally posted by 4923crew View Post
    As I tested various options on this gripen, there is no need for a gyro.
    I've yet to find a R/C plane that NEEDED a gyro. Almost all fly better and smoother, especially in gusty winds, with a gyro.

    Leave a comment:


  • 4923crew
    replied
    As I tested various options on this gripen, there is no need for a gyro. However to verify a gyros flying envelope i tried a gyro in the Gripen and of last weekend this was the only canard/Delta jet I've owned and temporarily flying with a Installed hobbyeagle A3 gyro. I few it 10 times and What i found is that there’s zero need to reverse any servos and defiantly zero need for two gyros to make this jet a gyro Assisted jet. I also have the ability yo remove aileron controls to the canards at the flick of a switch. I will make a video of my transmitter settings and of how I set up the jet after work today to help with some of the confusion ive seen here.

    Leave a comment:


  • Airguardian
    replied
    Now that's an interesting idea!

    Would solve the problem of needing to invert a servo direction.

    Leave a comment:


  • kallend
    replied
    Originally posted by xviper View Post
    Not sure how that would work. You could try it, but if you separate the channels on the A3L, now you've got one acting as elevator and the other as aileron (if the A3L is set as "normal wing"). You can't set the A3L as "elevon" for obvious reasons. Then comes the mixing in the TX if you use two open ports on the RX and tell them both to act as elevators, BUT, how does the A3L decipher two elevator signals when you've got them plugged into two different inputs and outputs (1 ELE and 1 AIL for each)?
    I suspect you could set it up as "elevon" with the roll gains set to zero so it only stabilizes pitch. haven't tried it (yet).

    Leave a comment:


  • FlyBoy90803
    replied
    Originally posted by Airguardian View Post

    Hope you were referring to the 2 gyros thing and not to crashing the jet by stalling it on high alpha!

    I don't have personal experience with that gyro but, as I've said a few times in the thread, use rate (normal) mode rather than 'heading' hold or 'autolevel' functions, use a normal pitch-to-canards trim on the transmitter and experiment with it. With my particular gyro I can set maximum gain and I don't suffer any oscillations but that could be gyro specific so best praxis is to start with medium/low gain and slowly increase it until the jet starts oscilalting or until you like the feeling best.

    Then the more aft you move your CG, the more 'scale' the canards will act while working with the gyro on.
    Of course, there's a limit to that, if you set CG ridiculously aft, not even the gyro would keep the jet stable but doubt that's gonna be an issue here considering how hard it is to shift CG back on this bird.

    And of course, if you manage to actually get a very-aft CG setup with gyro on, DO NOT turn it off.

    If you are flying balanced and turn the gyro off, it wouldn't be a problem though, but if you got into 'slightly tail-heavy' realm, switching gyro off could be a handful to keep the aircraft under control.

    My canards gyro is always on, both on this jet and on the Eurofighter.
    The Eurofighter is 'permanently tail-heavy' and the Gripen, hopefully will soon join the ranks. :)
    Haha yes I was talking about 2 gyros, its not worth the hassle trying to dial it in with just my Spektrum 8360T. Makes sense that if I am flying aft, turning off gyro will result in... money spent! I have made that mistake before. Thanks for the help.

    Leave a comment:


  • Airguardian
    replied
    Originally posted by FlyBoy90803 View Post



    Thats what im going to do, Any suggestions on setting up canards with HobbyEagle A3L?
    Hope you were referring to the 2 gyros thing and not to crashing the jet by stalling it on high alpha!

    I don't have personal experience with that gyro but, as I've said a few times in the thread, use rate (normal) mode rather than 'heading' hold or 'autolevel' functions, use a normal pitch-to-canards trim on the transmitter and experiment with it. With my particular gyro I can set maximum gain and I don't suffer any oscillations but that could be gyro specific so best praxis is to start with medium/low gain and slowly increase it until the jet starts oscilalting or until you like the feeling best.

    Then the more aft you move your CG, the more 'scale' the canards will act while working with the gyro on.
    Of course, there's a limit to that, if you set CG ridiculously aft, not even the gyro would keep the jet stable but doubt that's gonna be an issue here considering how hard it is to shift CG back on this bird.

    And of course, if you manage to actually get a very-aft CG setup with gyro on, DO NOT turn it off.

    If you are flying balanced and turn the gyro off, it wouldn't be a problem though, but if you got into 'slightly tail-heavy' realm, switching gyro off could be a handful to keep the aircraft under control.

    My canards gyro is always on, both on this jet and on the Eurofighter.
    The Eurofighter is 'permanently tail-heavy' and the Gripen, hopefully will soon join the ranks. :)

    Leave a comment:


  • xviper
    replied
    Originally posted by FlyBoy90803 View Post

    That makes sense, Y is the best way to go.
    It may not be the only way. I suppose it's possible to use a fancier gyro. The A3L is the simplest of the HobbyEagle gyros and for almost all my applications, the more expensive gyros aren't needed.

    Leave a comment:


  • FlyBoy90803
    replied
    Originally posted by xviper View Post
    Not sure how that would work. You could try it, but if you separate the channels on the A3L, now you've got one acting as elevator and the other as aileron (if the A3L is set as "normal wing"). You can't set the A3L as "elevon" for obvious reasons. Then comes the mixing in the TX if you use two open ports on the RX and tell them both to act as elevators, BUT, how does the A3L decipher two elevator signals when you've got them plugged into two different inputs and outputs (1 ELE and 1 AIL for each)?
    That makes sense, Y is the best way to go.

    Leave a comment:


  • xviper
    replied
    Originally posted by FlyBoy90803 View Post

    That makes sense, what about just leaving them as separate leads? Would I just use elevator and aileron ports then plug those into two open spots on my receiver? Trying to figure out the easiest solution.
    Not sure how that would work. You could try it, but if you separate the channels on the A3L, now you've got one acting as elevator and the other as aileron (if the A3L is set as "normal wing"). You can't set the A3L as "elevon" for obvious reasons. Then comes the mixing in the TX if you use two open ports on the RX and tell them both to act as elevators, BUT, how does the A3L decipher two elevator signals when you've got them plugged into two different inputs and outputs (1 ELE and 1 AIL for each)?

    Leave a comment:


  • FlyBoy90803
    replied
    Originally posted by xviper View Post
    If you are going to "Y" the canards together, first you must make sure they both work in the same direction, so if they don't, then you'll need to reverse one with a reverser or rewire the servo's internals. Once they're going in the same direction (and the correct direction), you can plug that "Y" lead into the ELE output of the A3L. From the A3L to the RX, you'll need to plug that lead into whatever port you decide to use to make the canards work. Dial in the gain either conservatively to start with or hook up the master gain from the A3L to the knob or slider on your TX (a different one than what you are using for master gain on the main gyro).
    That makes sense, what about just leaving them as separate leads? Would I just use elevator and aileron ports then plug those into two open spots on my receiver? Trying to figure out the easiest solution.

    Leave a comment:


  • xviper
    replied
    Originally posted by FlyBoy90803 View Post


    I set mine up on my DX9 with elevons and rudder as well. I was wondering if I could y the canards and plug them into an open channel and get them to work for pitch. I have an Hobbyeagle A3L so I might just do that and not worry about spending hours trying to get it to work with my 8360T.

    If I can figure it out I will certainly let you know but sounds easier to just set up separate gyro for the Canards. Any suggestions on setting up canards with HobbyEagle A3L?
    If you are going to "Y" the canards together, first you must make sure they both work in the same direction, so if they don't, then you'll need to reverse one with a reverser or rewire the servo's internals. Once they're going in the same direction (and the correct direction), you can plug that "Y" lead into the ELE output of the A3L. From the A3L to the RX, you'll need to plug that lead into whatever port you decide to use to make the canards work. Dial in the gain either conservatively to start with or hook up the master gain from the A3L to the knob or slider on your TX (a different one than what you are using for master gain on the main gyro).

    Leave a comment:


  • FlyBoy90803
    replied
    Originally posted by Airguardian View Post
    Using two separate gyros is the easy and most straightforward way to solve this and what I did on mine. ;)



    I did that already! (shame on me, right?)
    Walked up to the crash site, unclogged the fan, extended LG, put the jet back on the runway and took off again as if nothing.



    Thats what im going to do, Any suggestions on setting up canards with HobbyEagle A3L?

    Leave a comment:


  • FlyBoy90803
    replied
    Originally posted by kallend View Post

    That is a very good question.

    I have an 8360T in mine (iX20 Tx) but the gyro is only on the elevons and rudder. I *think* I know how to apply the AS3X to the canards, but only if the pitch trim also operates on the canards, which I don't want. I sent a suggestion to Spektrum suggesting uncoupling the canard trim from the elevon trim but I doubt it is high on their list of priorities.

    It might be easier just to add a separate Hobbyeagle A3L on the canards!

    If you figure it out, perhaps you'll report back.

    I set mine up on my DX9 with elevons and rudder as well. I was wondering if I could y the canards and plug them into an open channel and get them to work for pitch. I have an Hobbyeagle A3L so I might just do that and not worry about spending hours trying to get it to work with my 8360T.

    If I can figure it out I will certainly let you know but sounds easier to just set up separate gyro for the Canards. Any suggestions on setting up canards with HobbyEagle A3L?

    Leave a comment:

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