ACE GT5 gyro upgrade with new dongle

[DFC]

Both my GT5.0s had the same sensor calibrations which makes me suspicious!
I too have piro problems; OK turning to the right but wanders to the left. However, not sure its the piro compensation which is at fault as I think this is supposed to be about piros in forward flight, not in hover.

[maddog7]

I think you're asking about what happened when I put the TREX500 DFC in the Align Hughes 500 fuselage with an align 4 blade rotor head and spin blades.
First I don't fly 3D so the TREX 500 was set for ordinary circuits etc. At this point I was using the GT5.0 SAS. The governed rotor speeds on the Hughes were 1600, 1750 and 1900 rpm.
There were two main problems.
One was that with the 4-blade head at 1,600 rpm the tail rotor could only just hold the heading and sometimes started to let go. I solved this by fitting 550 blades (since cut down a bit).
The other was that the align ESC on governor control seemed to be too harsh and the tail gyro in the SAS couldn't keep things steady. It was very twitchy and no amount of adjustment would improve things. I solve this by fitting a Castle75 Pheonix ESC with the governor gain set quite low. Everything now worked very smoothly. I had the ESC connected to the RX via a long jump lead so I could break into he circuit to adjust the ESC parameters and to use its data logger to check currents, speeds and temperatures. I dropped from a 6 cell to a 5 cell battery to keep speeds down. (Already had 11T pinion).
At this point with everything working smoothly I did a tidy up, removed the jumper lead, and connected the ESC control lead direct to the RX before installing in the fuselage for the "final time".
On the next flight the Hughes 500 went berserk on take-off and crashed. I changed the gyro, the RX, the servos with no improvement a which point I stopped using the BEC in the Castle ESC and installed a separate BEC / battery system for the RX /servos. Hasn't been a problem since then. Castle say the BEC (5A) was probably being overloaded but I'm not entirely convinced.
I'm now flying the Hughes 500 with a GT 5.2 SAS not my replacement 5.0 and it's fine. I don't think the PID settings from the TREX 500 to the Hughes 500 needed to be changed much at all. It was all about tail rotor, smoother governor control, tail gyro adjustment and a 5 cell battery.

Oh bugga! bad luck on the Hughes, I was looking at your blog, looked like a real nice job! Hopefully not too much damage....
I've heard only negative things about the align ESC in gov mode, everyone instead advocating just running flat curves. This is what I've done and it's a powerhouse.
Tail on mine is on STD blades but a FS servo, makes a massive difference.
Unless I'm mistaken I think the swash tilt compensation part of the setup IS for piro "levelness" and the PID-->Tail gyro-->Consistency setting is used to prevent whip/weather vaning in FF/FFF.


D

[DFC]

That's pretty much exactly what I did.

Have any of you tried calibrating the sensors? I did it on mine since I was convinced the calibration was out, though not by much.
Again it was done prior to it's first fitting in a bird so I had nothing to compare to.

I do have a slight issue with piro consistency, it tends to stray off axis when piro'd in one direction, not so much in the other.
I've done the setup thing in the same way as the beastx (in fact I'm convinced either the HW or SW or both are made/developed by the beastx dudes!) ie Tilted swash maintains direction as airframe is piro'd.

Any thoughts....

I have now re-calibrated the sensors in both my upgraded GT 5.0s. I was suspicious of the values after the upgrade which did not entirely match some I had noted probably a year or more ago.

I could find no GT 5.2 notes about re-calibration (only about not doing it). There were some notes with earlier GTs. These notes say: "de-install the GT5 from the helicopter, connect it with an external battery and switch on. Now you can select the 3 different menu items of the sensors. First do a 2x tap to activate the menu item. Do another 2x tap to set the value to 0. Now rotate the GT5 around the given axis and you can see how the 0 changes its value. The value in the display has to change from 0 to 89 if you rotate it over 90 degrees. If a higher number is displayed (eg 92) he value of he axis has to be adjusted." etc etc.

When I did it, I left the gyro installed on the heli but used a separate battery, not the BEC (really for safety more than anything else). What I found was that as the heli was rotated through 360 degrees on (say) the vertical axis, the display went 0,1,2,..... 88,89,90,-90,-89,-88,....... -2,-1,0,1,2,..... etc etc. I then adjusted the sensor setting so after a 360 degree rotation the gyro was back at 0 after going through 4 of the 0 to 90 cycles (two in reverse). This seems to have worked very well and is much easier than removing the gyro from the heli. If the gyro is removed then 90 degree rotations are easy because the gyro sides are at 90 degrees relative to each other. If the gyro is left in situ then 360 degree rotations about all three axes are easier than trying to do 90 degrees.

DFC

[maddog7]

I suppose it depends on how the Gyro calibration procedure is supposed to work. Your method sounds very sensible to me. I did it with the gyro off the heli since I happened to have them off at the time. The problem is, without the exact procedure from TT there is no real way of knowing if you have it right or not?
Did you notice an improvement in flight after calibration?
For infromation the GT5 is "just about" square! all of the ones I've looked at (currently 4) have a wobble on the base where the screws go in. Also the sides are not always straight! I just had to get as close as I could. Unfortunatley I've not done a before and after (without touching anything else) so I can't say if I noticed any difference?
D

[DFC]

I don't think it made any difference to the flight behaviour but then I don't do 3D. I am just re-assured that the calibration is better than it was. One axis on one gyro was quite a long way out.