Hi, I’ve been battling for ages trying to get a nano talon setup with a pixhawk. I’ve run through the v-tail setup page:
http://ardupilot.org/plane/docs/guide-vtail-plane.html
After lots of trial and error the best I could was to reverse the weighting of the Ele and Rud channels (2 and 4) on my Taranis, then reverse SERVO2_REVERSED but leave SERVO4_REVERSED normal. After this I get the correct responses from the http://ardupilot.org/plane/docs/guide-vtail-plane.html#servo-reversal section, the correct responses from http://ardupilot.org/plane/docs/guide-vtail-plane.html#confirm-servo-reversal section, but I get the opposite responses from the ‘vtail rudder direction’ check - ie. when I roll the plane to the right, the right aileron goes down but the right v-tail goes up.
I cannot for the life of me work out how to get it all working correctly. Has anyone got the nano talon working with arduplane and could share settings? How can I reverse the vtail rudder direction - is there a setting somewhere?
I really think this is the last step before I can go flying!
You’re correct that that page can be confusing. It needs to be rewritten like this one – http://ardupilot.org/plane/docs/guide-elevon-plane.html
Use it as a reference for the procedure, but repleace “elevon” with “vtail” and “pitch/roll” with “pitch/yaw.”
To see if the stabilizing behavior is correct in the yaw direction, add a bit of YAW2SRV_DAMP. It will add rudder to counteract yaw.
@fnoop
Here is my nano talon running 3.8.5 with an mro pixracer and no airspeed sensor. I tuned it slightly but still need to tune it more, thunder and lightning scared me out of the sky. Nate is right that page is the one I used to figure out how to get mine setup. Also make sure in whatever flight mode you fly (me FBWA) in you have enough pitch, I found with the default mixing_gain setting of 0.5 did not have enough pitch and found 1 to work very well.
Nano_talon_tuned_3.8.5.param (14.3 KB)
@Naterater @anon94298870 Thanks for the responses! I just couldn’t work out what was wrong so wiped the firmware and started again. @anon94298870 your reversals are different to mine, can you confirm that you have normal weighting/reversals on your RC, and that you have left vtail servo plugged into rc2 and right vtail servo plugged into rc4?
Do all of the tests on the vtail page: http://ardupilot.org/plane/docs/guide-vtail-plane.html work as expected?
I couldn’t get the FBWA tests and the rudder direction tests to work together, one of them was always wrong no matter what I tried to change.
I have a pixhawk mounted upside down in the lower downward facing bay, so set the AHRS_ORIENTATION to ROLL180.
My taranis x9d+ is setup as AETR, with the elevator reversed in the mixer setting. I can confirm this worked and flew about 8 hours in the past 10 days with that setting. Also make sure and put some fiber tape where the wings and tails attach to fuselage. I had a wing detach from about 40m. Nano survived very well minus the wing support plastic piece, which if you look on yeggi there is a 3d printable replacement. Also my param file is by no means tuned perfectly but will get you flying comfortably.
Oh great tip about yeggi! I had already broken the middle plastic wing spar bit and one of the front plastic thingees that the front cover goes into, in some of my many crashes trying to get airborne.
I now can’t get the damned ESC working after wiping the firmware, it just beeps incessantly. Will try again…
Just re calibrate esc according to http://ardupilot.org/plane/docs/guide-esc-calibration.html. either option one or two. Option one worked for me many times although I usually forget a step hahaha. Your board orientation is correct. Again make sure and put some sort of lightweight tape on tail and wing sections, if anything goes wrong it will keep them attached and the autopilot will recover but without them its got no chance. And anyone looking for parts for this platform go to yeggi.com and search nano talon plenty of stuff there
@MCR87 Does this mean go to the mixer screen, edit E and change the weighting to -100?
Yes sir that’s how mine is setup, can you describe your control motions in manual and then in fbwa just using the rc?
@MCR87 - OK so I’ve done the entire setup again from scratch, compared my settings to yours and the important ones are the same.
So following the tests on this page: http://ardupilot.org/plane/docs/guide-vtail-plane.html
The roll and pitch tests are correct. The yaw is incorrect, in that if I yaw to the right (stick bottom right), then the right vtail goes down and the left vtail goes up. That’s the wrong way round isn’t it? The doc page is poorly written here, it should be less ambiguous, but I assume by ‘Both vtail surfaces go right’ it means the same directions that the right roll gives?
If I flip the reversals in SERVO2 and SERVO4 then the rudder/yaw is correct, but the pitch up and down is reversed.
This is driving me insane.
if you pretend you are in the pilot seat the control surface should wave at you when facing the direction of the stick input.
roll right; right aileron comes up and waves at you; left goes down; opposite for roll left
pull stick back; elevators come up and wave at you; opposite for pitch down
yaw right; rudder waves right; opposite for left
obviously vtail is just a rudder and elevator mixed but same applies.
if you input only rudder both should move the same direction of the stick when looking at plane from rear down.
have you tried switching the servo input cables on the vtail? this problem can occur on flying wings with elevons as well. it has to do with the way the servos are installed mechanically as the output shafts can be going different directions on each side with same PWM input.
Yes I’ve tried reversing the wiring of servo2 and servo4 (left/right vtail), same problems just in reverse! I can get 2/3 tests work at any one time, unless I’m being really thick (entirely possible), there’s something wrong with the mixing.
It took me quite a bit of trying to get mine setup properly, and I do remember going through the same struggles you did and somehow I got it to work. I will send you my taranis file once home maybe that will help.
Based on your servo connections, I believe it is entirely possible to have 2 “right vtails” so long that the servos respond correctly to all inputs.
As a reference, do all of the setup in FBWA mode. Do NOT use your transmitter – that gets confusing.
Work on 1 channel/servo at a time. Set the function. Leave your transmitter neutral and physically pitch the aircraft up. You should see the vtail move downward to correct the pitch. Return to neutra. Now roll the aircraft in 1 direction. The ailerons should attempt to correct that roll, and your rudder should move in the OPPOSITE direction of the roll (ie. out of that roll).
If one of the responses are correct but not the other, switch the servo function. If both responses are incorrect, switch the servo reversal.
Then proceed to the 2nd servo.Only after that’s done use your transmitter to double-check that your rc inputs aren’t switched.
@Naterater Thanks for the response, lots of ideas here for me to try. A lot of what you say is very different/contradicts the vtail doc page so if you’re right that should be updated ASAP. In particular, are you saying that in FBWA and I roll the aircraft to the right, the right aileron should go down, but the right vtail should go up? They should be opposite?
Correct. FBWA will try to keep the plane straight and level. By using FBWA you eliminate the transmitter as a source of error. Far too many people accidentally have transmitters reversed.
You’re right about the V-tail as well. When everything is correct, your left Vtail will move left and down as well.
@Naterater @anon94298870 @Coby Ok thanks a lot for all the information. After reading up about vtails and yaw, all your tips and the elevon doc page, I think I’ve finally got it all setup correctly, and hope to get flying tomorrow.
I’m also still really unsure about the best way of getting airborne and landing, and how to autotune. Will be a nailbiting experience!
Thanks for all the help.
I can tell you that is is a quite durable platform minus where the wings are held together but if you look up nano talon on thingiverse you will find plenty of spares. I pile drove mine into the ground the other day because it lost a wing mid flight was really hauling. Again tape the tail and wings on when flying save you a crash. not sure what mine weights but i just arm it throttle to mid-60% hold pitch back and let her rip pretty easy to take off and land. For autotune just add the mode to flight modes flick the switch and work the controls left to right and up and down for a good long while the longer the better. once done switch back to fbwa or whatever flight mode you fly in. I have added fiber tape to the outside of mine and can tell you that it made a huge difference, I also tore the flimsy battery tray out and added a 1.5mm carbon plate on the bottom. Mainly bought this as a fun little tester and to let other folks fly. It is a fun little plane.
as tightly coupled as they have that v tail make sure your CG is in the proper range. don’t have a nano talon so not sure what it is. the wing looks pretty rectangular so about 20% of root chord back from leading edge; a guess if you want a little static stability margin. if you get it too far back it will want to nose up too much and stall. not an arduplane guru so not sure how good it is at masking those issues. since the tail moment is pretty short you do not have a lot of control authority in pitch and yaw. i keep reading it’s a nice little plane once it’s set up. i don’t know how many planes i have hauled away in trash bags. probably too many. take your time and have fun. take off is optional; landing is mandatory.
EDIT: ok it has a bit of sweep out at the tips. but since it’s straight trailing edge 20% likely still works. someone around here must know a good CG.