Demon Cortex Gyro question
10-18-2014, 10:08 PM
#201
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Check to see if the tray it's mounted on is level or if the front is slightly higher. I've had one install that had an issue of elev coupling on roll. Turned out my tray was lower in the front than back to the thrust line. Made a wedge to put the gyro level and problem was solved.
Jan
10-19-2014, 05:39 AM
#202
I saw the same phenomenon in my Elan because I got it a little crooked.. I tried it and had to put a couple clicks of rudder trim in.. good point about the pitch vs tray vs thrust line.. you do want to mount it as orthoganal as possible..
It doesn't matter WHERE its mounted though.. it could be on a wing tip or on the rudder, but it does need to approximate the Axis' of the plane
It doesn't matter WHERE its mounted though.. it could be on a wing tip or on the rudder, but it does need to approximate the Axis' of the plane
10-20-2014, 02:08 PM
#204
ever enabling it in flight. It worked out fine in the end.
10-20-2014, 04:14 PM
#206
Hi
Sorry if these are answered, I tried to research the thread.
1.) Are all of the servo power leads going through the little box? Does the power bus in the gyro have a current rating?
2.) If a plane has a conditional mix, like flap to elevator, how does that work? Say you had down elevator mixed to flap extension. I thought the gyro would see the down elevator input as a rate command and the plane would keep slowly drifting downward in pitch?
Thanks very much...
BTW, I just came from Best in the West......I think there were a LOT of these flying......
Sorry if these are answered, I tried to research the thread.
1.) Are all of the servo power leads going through the little box? Does the power bus in the gyro have a current rating?
2.) If a plane has a conditional mix, like flap to elevator, how does that work? Say you had down elevator mixed to flap extension. I thought the gyro would see the down elevator input as a rate command and the plane would keep slowly drifting downward in pitch?
Thanks very much...
BTW, I just came from Best in the West......I think there were a LOT of these flying......
10-21-2014, 07:29 AM
#208
Hi
Sorry if these are answered, I tried to research the thread.
1.) Are all of the servo power leads going through the little box? Does the power bus in the gyro have a current rating?
2.) If a plane has a conditional mix, like flap to elevator, how does that work? Say you had down elevator mixed to flap extension. I thought the gyro would see the down elevator input as a rate command and the plane would keep slowly drifting downward in pitch?
Thanks very much...
BTW, I just came from Best in the West......I think there were a LOT of these flying......
Sorry if these are answered, I tried to research the thread.
1.) Are all of the servo power leads going through the little box? Does the power bus in the gyro have a current rating?
2.) If a plane has a conditional mix, like flap to elevator, how does that work? Say you had down elevator mixed to flap extension. I thought the gyro would see the down elevator input as a rate command and the plane would keep slowly drifting downward in pitch?
Thanks very much...
BTW, I just came from Best in the West......I think there were a LOT of these flying......
2) The response of the gyro (at least in normal mode) is simply to correct a disturbance; it doesn't try to hold a 'rate'. Presumably in your conditional mix example the mix is there to prevent a pitch change; therefore the gyro will do very little (if anything) other than to continue to smooth out the flightpath. Also, I would guess that in most cases the amount of elevator mix in your example would be small enough to be irrelevant (in the same way that the effects of trimming the model can largely be ignored).
10-21-2014, 08:07 AM
#209
2) The response of the gyro (at least in normal mode) is simply to correct a disturbance; it doesn't try to hold a 'rate'. Presumably in your conditional mix example the mix is there to prevent a pitch change; therefore the gyro will do very little (if anything) other than to continue to smooth out the flightpath. Also, I would guess that in most cases the amount of elevator mix in your example would be small enough to be irrelevant (in the same way that the effects of trimming the model can largely be ignored).
Sorry I should have been clearer, I was talking about the gyro being in rate mode when this occurs. And as for ignoring trim, I thought it was important to set these things up with no trim in the TX, else the gyro interprets the trim as a rate command? That was the whole gist of my question, wouldnt the elevator mix look just like a rate command to the gyro (when the gyro is in rate mode)?
EDIT: I mean it might not be important. I use a similar gyro and I don't know the answer on that one either hence the question. And on the one I use I cant run 10 amps over that little set of copper traces, so that it is an advantage.
THanks
Last edited by mr_matt; 10-21-2014 at 08:23 AM.
10-21-2014, 08:29 AM
#210
The way that I understand it is that there is no rate 'command'.
By moving your control stick you don't ask the gyro to give you a rate of movement, the signal is (simplistically) passed straight through the gyro to move the control surface. The gyro simply responds to any disturbance of the model and 'alters' this signal to provide a correction to smooth down the flightpath (in normal/rate mode).
By moving your control stick you don't ask the gyro to give you a rate of movement, the signal is (simplistically) passed straight through the gyro to move the control surface. The gyro simply responds to any disturbance of the model and 'alters' this signal to provide a correction to smooth down the flightpath (in normal/rate mode).
10-21-2014, 11:05 AM
#211
The way that I understand it is that there is no rate 'command'.
By moving your control stick you don't ask the gyro to give you a rate of movement, the signal is (simplistically) passed straight through the gyro to move the control surface. The gyro simply responds to any disturbance of the model and 'alters' this signal to provide a correction to smooth down the flightpath (in normal/rate mode).
By moving your control stick you don't ask the gyro to give you a rate of movement, the signal is (simplistically) passed straight through the gyro to move the control surface. The gyro simply responds to any disturbance of the model and 'alters' this signal to provide a correction to smooth down the flightpath (in normal/rate mode).
10-21-2014, 11:33 AM
#213
It certainly seems, based on flying, that it does much more than simply dampen out disturbances. Certainly much more so than heli rate mode gyros of old. For example, I have a plane that was almost impossible to maintain a constant roll rate in a cross wind. Things like rolling harriers were always extremely difficult to perform with this airplane as it always would want to stop rolling depending on what the wind was doing and it would require almost full aileron to get it going again. The same plane, with the Cortex set to normal mode doesn't have this issue at all. Simply give it enough aileron to start it rolling at the desired rate, hold that input and the Cortex appears to take care of the rest. It seems to very effectively maintain a constant rate of change, for each axis based on stick input.
10-21-2014, 12:47 PM
#214
OK I am confused, if that is what it does, that is what I was referring to as a "rate" mode. Meaning a deflection angle of the stick does not directly correlate to a deflection angle of a surface, but rather the deflection angle of the stick corresponds to a desired rotation rate around that axis (and the gyro takes care of any wind effect, turning, coupling etc)
So that is what my original question was. If you have a elevator compensation mix in for flaps, the gyro can't distinguish that from a down elevator rate command. Maybe you don't need these kind of compensation mixes in the first place with the rate mode.
10-21-2014, 02:19 PM
#216
OK I am confused, if that is what it does, that is what I was referring to as a "rate" mode. Meaning a deflection angle of the stick does not directly correlate to a deflection angle of a surface, but rather the deflection angle of the stick corresponds to a desired rotation rate around that axis (and the gyro takes care of any wind effect, turning, coupling etc)
So that is what my original question was. If you have a elevator compensation mix in for flaps, the gyro can't distinguish that from a down elevator rate command. Maybe you don't need these kind of compensation mixes in the first place with the rate mode.
So that is what my original question was. If you have a elevator compensation mix in for flaps, the gyro can't distinguish that from a down elevator rate command. Maybe you don't need these kind of compensation mixes in the first place with the rate mode.
I also have limited experience with the Cortex in a Jet that has elevator compensation when the flaps get deployed and that doesn't seem to bother the Cortex either. Once we got the elevator trimmed for the desired glide slope, it didn't seem to change whether the Cortex was enabled or not. Whatever it's doing, it doesn't SEEM to be too worried about mixes, yet does a great of stabilizing the plane.
10-26-2014, 06:03 PM
#217
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Seems to me you could program different gains....different than the "normal"(amber light) onto the HH(red light) if you do not intend on using HH. Still you would need to use the computer to make indiviual changes but you could use the 3-position switch to see the difference in the normal setting and your new gain settings.
10-27-2014, 06:02 AM
#218
Seems to me you could program different gains....different than the "normal"(amber light) onto the HH(red light) if you do not intend on using HH. Still you would need to use the computer to make indiviual changes but you could use the 3-position switch to see the difference in the normal setting and your new gain settings.
Absolutely! Bank one is Amber and default is rate mode, Bank two is Green and default is heading Hold, Red is OFF.
Depending on your radio you could have as many different gain as you like, you can setup rate and hold settings in each bank for one or all of the Axis' by using the PC software. Jeti radio users are using a pitot sensor to change the gains setting in flight automatically. This unit has great flexibilty!
11-19-2014, 01:42 PM
#219
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Hi Airforce7,
To setup the gyro, make sure your TX is completely ready to fly the model with the correct travel etc. Turn Dual rates off.....
Then to teach the gyro, you need to do the following....
1. Turn everything off
2. Place jumper into gyro
3. Then turn on your transmitter with neutral sticks and dual rates OFF.
4. Turn on your model.
5. This is where you need to be quick.... the LED will cycle through the various controls. For you, the gyro light sequence will be....
2 x RED blinks (Do nothing)
2 x GREEN blinks (Right Aileron)
1 x GREEN blink (Left Aileron)
2 x GREEN blinks (Aileron Neutral, Elevator Push - Down)
1 x GREEN blink (Aileron Neutral, Elevator Pull - Up)
2 x GREEN blinks (Aileron + Elevator Neutral, Rudder Right)
1 x GREEN blink (Aileron + Elevator Neutral, Rudder Left)
When the system blinks fast continously, Pull the jumper out and power the model down. The above step happens fast, so you need to be aware of which input to give beforehand, otherwise you'll put in a wrong input or miss it altogether, as the gyro doesn't wait for you.
I remember having to do this a couple times before I got it done right. Remember, the gyro 'learns' your end points AND stick position during the above sequence - ie: During the time the jumper is in the gyro.
Regards,
Mort
To setup the gyro, make sure your TX is completely ready to fly the model with the correct travel etc. Turn Dual rates off.....
Then to teach the gyro, you need to do the following....
1. Turn everything off
2. Place jumper into gyro
3. Then turn on your transmitter with neutral sticks and dual rates OFF.
4. Turn on your model.
5. This is where you need to be quick.... the LED will cycle through the various controls. For you, the gyro light sequence will be....
2 x RED blinks (Do nothing)
2 x GREEN blinks (Right Aileron)
1 x GREEN blink (Left Aileron)
2 x GREEN blinks (Aileron Neutral, Elevator Push - Down)
1 x GREEN blink (Aileron Neutral, Elevator Pull - Up)
2 x GREEN blinks (Aileron + Elevator Neutral, Rudder Right)
1 x GREEN blink (Aileron + Elevator Neutral, Rudder Left)
When the system blinks fast continously, Pull the jumper out and power the model down. The above step happens fast, so you need to be aware of which input to give beforehand, otherwise you'll put in a wrong input or miss it altogether, as the gyro doesn't wait for you.
I remember having to do this a couple times before I got it done right. Remember, the gyro 'learns' your end points AND stick position during the above sequence - ie: During the time the jumper is in the gyro.
Regards,
Mort
Mort,
Thank you , thank you, thank you!!! Thanks for putting the teaching/learning process in a way that I could easily grasp it. Wow, it's dang easy, once I read the way you said do it!!
Now to go fly this thing on a windy day to experiment, and learn more, before I put the Cortex in my 60cc Corsair.
Thanks for the help!
Chris https://www.youtube.com/watch?v=GPYVcyl0HRE
11-30-2014, 04:31 PM
#220
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O.K. here is one for you guys.
I set my Cortex to use the Bank one amber light as the default...the red light is off of course. On the Bank two...green light.... I programmed it to only use rudder control only. When I go to Bank one(amber) everything is great ....Off at red works....BUT when I switch to Bank two(green) the rudder will creep over to the right side and stay there until I turn off the Bank two by going to red or amber. I wanted to fly some maneuvers in the heading hold using rudder only but the rudder does this little trick.....any idea?
I set my Cortex to use the Bank one amber light as the default...the red light is off of course. On the Bank two...green light.... I programmed it to only use rudder control only. When I go to Bank one(amber) everything is great ....Off at red works....BUT when I switch to Bank two(green) the rudder will creep over to the right side and stay there until I turn off the Bank two by going to red or amber. I wanted to fly some maneuvers in the heading hold using rudder only but the rudder does this little trick.....any idea?
11-30-2014, 07:25 PM
#223
O.K. here is one for you guys.
I set my Cortex to use the Bank one amber light as the default...the red light is off of course. On the Bank two...green light.... I programmed it to only use rudder control only. When I go to Bank one(amber) everything is great ....Off at red works....BUT when I switch to Bank two(green) the rudder will creep over to the right side and stay there until I turn off the Bank two by going to red or amber. I wanted to fly some maneuvers in the heading hold using rudder only but the rudder does this little trick.....any idea?
I set my Cortex to use the Bank one amber light as the default...the red light is off of course. On the Bank two...green light.... I programmed it to only use rudder control only. When I go to Bank one(amber) everything is great ....Off at red works....BUT when I switch to Bank two(green) the rudder will creep over to the right side and stay there until I turn off the Bank two by going to red or amber. I wanted to fly some maneuvers in the heading hold using rudder only but the rudder does this little trick.....any idea?
12-01-2014, 06:21 AM
#225
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Normal for the rudder to "lay-over" on HH?.....well O.K. I will watch it very closely in the air when I switch it on....Thanks guys.....I really enjoy the Cortex.....very easy to setup and it works. Could be as Bob says about rudder trim...I think I did move the trim...I will check.
Last edited by Max2011; 12-01-2014 at 06:23 AM.