GPS 2 setup

[dogbreath]

I have Jeti xmtr, TREX 550L, 720BE, GPS2. I'm starting initial set up, and here is where I'm not sure what to do.

Previously, I was using a spring loaded switch as bank switch, with the spring loaded bank switched to self level ON. This was my rescue. I have separate A & B switches to control the GPS.

I can set Switch B to rescue now, but will my spring loaded bank switch continue to work as a rescue switch as well? The swash is not responding on the bench, but I'm guessing that could be that I haven't done a compass swing yet or the throttle is off (I read about a 10 percent signal) so this behavior may be changed from previous.

The module is 27cm aft of the shaft, but my magnetic field is 2.7. Is it affected by my work bench (tools) and things like the water heater to my right? I can move it farther aft using the longer cable. Anyone with a 550L have an optimum location?

Thanks in advance, Dan

[Xrayted]

Originally Posted by dogbreath

I have Jeti xmtr, TREX 550L, 720BE, GPS2. I'm starting initial set up, and here is where I'm not sure what to do.

Previously, I was using a spring loaded switch as bank switch, with the spring loaded bank switched to self level ON. This was my rescue. I have separate A & B switches to control the GPS.

I can set Switch B to rescue now, but will my spring loaded bank switch continue to work as a rescue switch as well? The swash is not responding on the bench, but I'm guessing that could be that I haven't done a compass swing yet or the throttle is off (I read about a 10 percent signal) so this behavior may be changed from previous.

The module is 27cm aft of the shaft, but my magnetic field is 2.7. Is it affected by my work bench (tools) and things like the water heater to my right? I can move it farther aft using the longer cable. Anyone with a 550L have an optimum location?

Thanks in advance, Dan

Basic SL will work as always. I have mine still set up on the momentary switch independent of the GPS rescues.

Keep in mind that any GPS rescue feature uses the SL function as part of the rescue. There is no reason that you would be using the SL switch if you already have rescue now activated in the first place, as the model will already be in SL and being held in position by the GPS until you switch back into manual flight.

Connect up to your PC and press the SL button while all GPS features are set to manual. You should see your banks change indicating the SL is working.

[dogbreath]

Thanks, XRayted.

Yes, banks change with the spring loaded switch, but on the bench there's no swash response like I got before the GPS install. I thought this might be due to the 10 percent throttle requirement or the lack of a compass swing yet. Throttle is locked out and motor also unplugged while I get things going. GPS eventually turned solid blue and had a position, and SuperBright was flashing green (may have been green/blue, I don't see those changes well), which means GPS had control.

My overall plan is to leave rescue on momentary, fly with GPS in manual mode 95 percent of the time, and use the GPS for it's other functions (It will go get a beer, won't it?) Dan

[Xrayted]

Originally Posted by dogbreath

Thanks, XRayted.

Yes, banks change with the spring loaded switch, but on the bench there's no swash response like I got before the GPS install. I thought this might be due to the 10 percent throttle requirement or the lack of a compass swing yet. Throttle is locked out and motor also unplugged while I get things going. GPS eventually turned solid blue and had a position, and SuperBright was flashing green (may have been green/blue, I don't see those changes well), which means GPS had control.

My overall plan is to leave rescue on momentary, fly with GPS in manual mode 95 percent of the time, and use the GPS for it's other functions (It will go get a beer, won't it?) Dan

I'm not personally aware that the GPS should have anything to do with anything, as the 10% rule only applies to the GPS functions, and your model will fly normally without the GPS being set up first. The LED will still turn green and the model will go into a ready state. It's easy enough to test in flight and see if the SL is still performing normally after getting it all set up.

On another note.......you do know that you dont have to use bank switching just for SL functionality since V4 software was released last year dont you? Its no issue to leave it as is, but you can simply assign the "self level gain" function to the same button rather than bank switching with a gain of 1 (there is no zero) for SL off position and whatever SL gain you want for the SL on position, and SL will work all within the same bank. You use the channel endpoints for the button to set the gain values.

[dogbreath]

Originally Posted by Xrayted

On another note.......you do know that you dont have to use bank switching just for SL functionality since V4 software was released last year dont you?

I did NOT know that. That's the way I've been setting up rescue since my first Blue, and just kept on going. I've learned a lot today!

thanks, Dan

[Xrayted]

Originally Posted by dogbreath

I did NOT know that. That's the way I've been setting up rescue since my first Blue, and just kept on going. I've learned a lot today!

thanks, Dan

Yep, its another option and you can clean up things by clearing out the second bank if that is the only reason you are using it. It will disappear when connected up if not being mapped to anything.

As stated, there is no "zero" gain, so a value of one is as low as you can go using the channel end points, but this is OK and there will be no self level at that value. It will however show up in every flight event log that SL is initiated because it still sees that "1" value.

Just make sure to connect up to the software and look under View/Gains used in flight to verify what actual SL gain you are getting, as this is not always 1 to 1 with your TX channel values. In my case 100 on my TX channel = 250 SL gain on the SK side, and its the SK side that matters.

[dogbreath]

I'll check the S/L out after the GPS gets set up completely. I'm only going to change one thing at a time. I'm ready to swing the compass when I get some time today. When I went back and powered everything up the SK led was solid and I had swash response to S/L engagement.

Dan

[dogbreath]

I got the compass swung. I had forgotten about the titanium in my wrist (it's fused), and I got errors a couple of tries about magnetic interference. I did take off my belt (think airport security), so one time my pants wound up around my ankles, but I wasn't going to stop mid-swing.

I get no swash response on spoolup with the GPS solid and the EXLED flashing quick blue/green. My Mezon is plugged into the R3, not the 720. Does that mean I need to use the 720 gov or does it just need to see a throttle signal in the UDI stream?

edit: In throttle cut, the swash DOES respond. in norma/idle1/idle2 it does not. In fact, it looks like it drops a bit more negative when the collective/throttle is above bottom.

double edit: Well, this one appears to be on me. I didn't have one of the switches set to manual! I'll test fly later. Duhhhh, me not so smart.

Hopefully this is the last little bump in the road.

Dan

[Xrayted]

Be very careful! Spooling the heli up with the GPS set to hard deck can result in the heli going autonomous and flying up to the set deck limit on its own completely out of your control. We have been asking for this to be corrected for some time now with still no correction from the SK side, so it falls on all of us to be aware of this "feature" for the time being.

It can be a very frightening situation especially since you havent tested yet to see if the GPS is even performing correctly, so who knows where it might take the heli!

You get used to the process after some time, but always make sure all GPS switches are set to manual before spooling up, and do not test any GPS feature without a lot of altitude and be ready to flip back quickly into manual mode if needed.

Always start by testing and verifying that position hold works first before trying anything else, as that is the end result of all other rescue modes and RTH. They can't work properly if PH isnt working

[dtfeld]

Also, if you spool up before the GPS has signal lock, the swash "Bumps" when it does get signal. This caused my 550 to jump up about 2 ft and plant right back down almost instantaneously.

Scared the holy SH*T out of me. Took me a minute yo figure out what happened

Now I keep throttle hold on until the GPS shows solid signal, then spool up.

[dogbreath]

I waited until the GPS was solid blue, & the ExLED was solid as well. The symptoms were that I had gps switch 1 reversed, so manual was down instead of up. Just made a quick hover with one finger on thottle hold! I won't get to check until this evening or tomorrow. I was 95% sure I sorted it out correctly in the setup software, but will go through it all again. I added GPS switch positions to the Jeti preflight check now, which I should have done first thing.

There was a lot of brain burnout by the end of the day which is why I decided to stop troubleshooting. I'll get it figured out...with help which I thank you all for. I post my self-induced problems because someone somewhere may not have to repeat them if they read about mine! The whole GPS thing for me is aobout learning how/why/what it does and see if I can gain something from it. The set up challenges are a good learning experience and keep my brain engaged. I'll never be a great pilot but I enjoy understanding electronic systems--a throwback to my young adult days troubleshooting/repairing electronic countermeasures equipment (1970s, F-111s).

Dan

[Xrayted]

Good luck and great idea on the Jeti preflight switch check! I set vibe and voice alarms on my DX9 for all GPS positions other than manual so it throws a hissy fit if powered up with them in any other position

I cant remember if we have covered this in any other post, but connect up to the PC with your TX powered and verify that positive collective from the TX shows green in the live data and negative red. Do NOT attempt to activate any GPS modes if this isnt correct!

It's possible to somehow get things reversed during FBL setup and the model will fly completely normal in manual mode, but any GPS rescue mode will slam the model into the ground instantly because it thinks down is up. Simple insurance before testing GPS

[georgi UK]

Originally Posted by dogbreath

troubleshooting/repairing electronic countermeasures equipment (1970s, F-111s).

Dan

=] Their base was 5 miles from here, known as 'flying pigs'! they still have display static versions inside the gates,,,,,,

[dogbreath]

I was supposed to ship out to RAF Lakenheath in 1979--I believe they were at Upper Heyford as well. I got selected to finish college on Uncle Sam's dime instead. I got an F-111 ride in 1978, lots of instruments, not much view of the sky. Still pretty cool for this aviation geek. Dan

[georgi UK]

=] Yes, Upper Heyford is where I'm at. To see a pair of Tomcats coming into land, or after-burn take-offs priceless!

[dogbreath]

Update:
Yes, I did have switch one reversed. It now works as it should. Quite windy today, so position hold bounced around a lot. I also tried return home, and realized that I had initialized in the garage. Hover over the garage was not too big of a deal, but I had toggled switch one five times when I sat it down outside. I think after reading the manual that I should have toggled switch 2 (man/RTH/Soft Floor) five times. Live and learn. Watching the heli fly over the house on it's own was a bit nerve wracking.

I double checked swash, positive collective is green. Nose up elevator, right roll, and yaw right are also green. Changed rescue from cyclic two to self-level gain, and set the two values for 1 and 201 per in-flight values. I think I'm there set-up wise. Again, all the help is greatly appreciated.

Dan

[Xrayted]

Great to hear it was an uneventful test! I have yet to ever get the "switch flip" reset of home position to work on my model no matter how many times or different ways I have done it, so maybe you will be more successful there.

My model will also overshoot the home position by at least 30 feet every time, but Im used to it now and flip back into manual before it gets to me. I use a RX pack for my electronics and power it up right where it sits for takeoff and sees throttle, so that should be home but never is. This may just be the error range that my unit exhibits in my particular flying location.

Its very reproducible though, and RTH will always park the model directly over my head every time. I swear it seems it follows my TX

Good luck on future testing!

[dogbreath]

Wind finally died down enough for me to really wring the gps out. My old rescue switch didn't work, but the gotcha there is that in the cyclic menu the rescue has to be set to on, even though gain is showing zero. The gains used in flight show 1 and 200 with the switch. Now that that's figured out, I wound up changing the GPS switch layout. Since switch one overrides switch two, I put the rescue soft floor on middle switch 1, and rescue now on down. Switch two has position hold middle and return to home on down. Panic will still let me hit rescue now, or the old rescue, even if something is set in switch two.

Testing return to home has put me in the Xrayted camp, with later RTH's coming closer to overhead! GPS drift? Crazy, but at least it performs. I got pretty far out once and RTH was the easiest way to come back.

Position hold had some bouncing, and rescue now had some mild toilet bowl, so I lowered the gain to 20 from 25. Will test that out later today. All in all, the GPS is pretty cool, and I've had fun playing with it.

Dan

[dogbreath]

Rescue soft floor seems to become position hold, in that it doesn't give me back control of collective after it stabilizes the heli. Is that the proper behavior of the mode? I seem to remember an old video that showed a heli bouncing back up and continuing to fly away. Was that hard floor?

Dan

[Xrayted]

Originally Posted by dogbreath

Rescue soft floor seems to become position hold, in that it doesn't give me back control of collective after it stabilizes the heli. Is that the proper behavior of the mode? I seem to remember an old video that showed a heli bouncing back up and continuing to fly away. Was that hard floor?

Dan

That is the correct behavior of both of the deck rescues. They both end in position hold until you flip back into manual and take back over.