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Official Freewing JAS 39 Gripen 80mm EDF Jet
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Originally posted by 4923crew View PostAs I tested various options on this gripen, there is no need for a gyro.
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 PostOn those calm days the Gripen is super smooth without gyro on, at least it feels that way to me.
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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 may resort back to just having one gyro AR8360T and leaving my canards un stabilized.
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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.
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.
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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.
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Originally posted by kallend View PostI'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.
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.
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Originally posted by Airguardian View PostNow 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.
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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.
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Now that's an interesting idea!
Would solve the problem of needing to invert a servo direction.
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Originally posted by xviper View PostNot 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)?
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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. :)
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Originally posted by FlyBoy90803 View Post
Thats what im going to do, Any suggestions on setting up canards with HobbyEagle A3L?
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. :)
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Originally posted by FlyBoy90803 View Post
That makes sense, Y is the best way to go.
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Originally posted by xviper View PostNot 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)?
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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.
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Originally posted by xviper View PostIf 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).
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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?
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Originally posted by Airguardian View PostUsing 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?
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