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  • in reply to: Free/Open source CAD software for 3D printing? #64119
    Kevin_Erik
    Moderator

    I use Fusion 360 for all my stuff…
    https://www.thingiverse.com/1Smug_Bastard/designs

    in reply to: Tricopter "Whirlygig" frame #64022
    Kevin_Erik
    Moderator

    @Adamcooney1

    That’s awesome! What material did you make the frame from?

    Just so you know I’ve made significant changes to the design, thus allowing the copter to be 30 grams lighter and flown inverted. The inversion grants a much smoother Yaw response, while keeping the motor thrust away from the frame.

    Once I feel happy with the build I may release the .STL. Though, not 100% sure of this yet as there’s also the desire to sell the frames to for cover the cost of future design improvements. In the mean time, I can have a copy made and mailed to you directly. Just need to work things out via PayPal to cover the costs of the print (Nylon / Carbon) and shipping ect.

    What you see in the attached photos, flew using…
    * BetaFPV 2-4S F4 Flight controller. (12 amp)
    * Openlog serial data recorder
    * Runcam “Robin” camera and TX200U transmitter
    * BF 4.1 and New RPM based filtering
    * 1105-5000kv brushless motors
    * Avan 3″ mini props
    * FrSky R-XSR F.Port (UART 2)
    * Bluebird Mini Servo, BMS-101HV (LED pad)
    * Mini-300 UBEC (Servo 7.4 voltage supply)
    * 50V capacitor

    Unfortunately, I’ve a defective BEC so the flight controller must be replaced. (still waiting for it)
    Edit: Can you please post your build on https://rotorbuilds.com/?

    Cheers!

    Kevin

    in reply to: Impossible LR #63988
    Kevin_Erik
    Moderator

    Just my opinion mind you but you may run into problems with the prints being fragile around the splines contact area. One good hit and while the servo maybe be fine, the tilt mechanism will be drastically off center from it.

    SLS Nylon and injection molded parts are by far the most resilient.

    in reply to: Kakute F4, RCE servo, and betaflight #63973
    Kevin_Erik
    Moderator

    @Bleek

    Correction…

    The standard Betaflight works with servos as I’ve several of my Tri’s running it. Only things Betaflight doesnt support is feedback and servo calibration. Neither of which are required to fly a Tri.

    Now as for the why, Triflight support stopped some where around Betaflight 3.2, as that was Lauka’s last release. (That i know of) Maybe someone can reach out to him and see if he’s managed any updates thats yet to be published?

    in reply to: Kakute F4, RCE servo, and betaflight #63963
    Kevin_Erik
    Moderator

    Older versions of Triflight can.

    Dont think that there has been any discussion about Tail Calibration being ported into the current version of BF.

    in reply to: Impossible LR #63940
    Kevin_Erik
    Moderator

    @Jihlein,

    What your seeing is the Mass of the Motor / Propeller as well as their Gyroscopic-Mass (GM) is being held closer to the Servos pivot point. This reduces the amount of induced Roll that results from the copters Yaw.

    Case-in-point: Your copter Yaws Left, thus bringing its Tilt-Mech Mass / GM Right, inducing Right Roll that the copter must now compensate for. The compensated Roll, induces both Yaw and Pitch changes that also must be compensated for and so on and so on. While some of this interplay can be compensated for or dampened by the Flight Controller, this doesn’t always work due to the Servos slow response time.

    The same is also true for the Mass / CG being too far above or below the copters true CG. However not to the extent seen from the Mass / GM being held far from the Servos pivot point. Now by using the shorter Tilt-Mech, the amount of interplay between each axis is drastically reduced. The closer the Mass / GM is held to the Servos rotational axis the smoother / faster the Tail-Mech can respond. (This can be seen in the tail calibration results)

    The Gyroscopic mass is based on the propeller length / mass. Which is why smaller Tricopters with lighter / smaller propellers appear to behave better. This IMO is one of the short comings of dRonin managing very small or very large copters due to the differences in propeller GM. If you don’t believe me, try running a large copter that has tuning issues using smaller propellers. The difference is night and day…

    Beyond all that, I’m still a fan of the “inverted” Tail-Mechanism. Simply because the copter Rolls in the direction of Yaw. Making the overall flight feel smoother and more predicable. Attached is a Step-Response from a 3″ inverted Tricopter I’ve been working on. (125-130 grams with 4S LiPo) While there is a little bit of P overshoot, the rest of the plot is really smooth. Keep in mind that I’ve yet to tune this copter and am currently using the BF (4.06) default PID’s. (except for Yaw) Previously, i built up a non-inverted version of this copter and the Step response wasn’t nearly as clean.

    Cheers!

    Kevin

    in reply to: PDP options For Tricopter LR #63727
    Kevin_Erik
    Moderator
    in reply to: Tail motor gets crazy. Need Help :/ #63626
    Kevin_Erik
    Moderator

    dRonin is the issue. Switch to Betaflight.

    in reply to: Betaflight works #63612
    Kevin_Erik
    Moderator

    The old version of Betaflight for Tricopters was called “Triflight”. Far as i know of, the ServoCal isn’t part of the current Betaflight build (4.0 +). Unless someone have made a separate branch specifically for this.

    That being said, a Tricopter will fly just fine using the current Betaflight due to it’s superior handling of filtering and the bonus of being able to use a data logger. Any data gathered can be run thru PIDtoolBox to figure out the copters step-response. Trust me, this is awesome sauce!

    https://github.com/bw1129/PIDtoolbox

    An older Step-Analyzer called Plasmatree does the same thing but doesnt have the nice GUI.

    https://github.com/Plasmatree/PID-Analyzer

    in reply to: Some technical difficulties… Arms folding back in flight #63566
    Kevin_Erik
    Moderator

    The arms would break long before the insert would.

    Kevin_Erik
    Moderator

    You can always ask someone to post their Betaflight log from a flight. This will show the current draw for each motor as well as the peak draw for the entire flight. For 20 ampss draw per motor you could use 18 AWG.

    Kevin_Erik
    Moderator

    Just use a thinner gauge wire. In most cases your line losses would be very minimal but this could also save weight on the copter. Keep in mind that, 16 AWG (1.53mm) wire is almost twice as heavy as 18 AWG (1.19 mm) wire. I mention this because all too often folks over do it when it comes to wire thickness and then wonder why the copters flight weight is much higher then they expected.

    The XT60 / XT30 pigtail, should always be either 14 (1.78 mm) or 16 AWG, depending on the size of the build and its “overall” current draw. On some extreme racing builds, I’ve seen 10-12 AWG used. Where the combined burst current can reach as high as 150 amps! However for our purposes, i doubt we’d see more than 30 Amps per motor without some serious throttling. Even then, the majority of the flight would see only just enough draw to maintain stable long range flight.

    If your flying primarily long ranged, then the copter is drawing a lower amount current over a longer period of time. Thus consider using 18 AWG wire between the ESC’s and PDB. For flights that are more likely to see heavy throttle use (higher burst current), 16 AWG is pretty much the standard. You could always see what others are reporting for the overall current draw (during stable flight) and then base your wire selection on that.

    Some insight from JB, https://www.youtube.com/watch?v=KkRBoa3ywyk

    and

    Oscar Liang, https://oscarliang.com/wire-awg-chart-quadcopter-rc/

    Side note: Always use silicone wires!

    Kevin_Erik
    Moderator

    No it wont cause problems… keep in mind that everything is in parallel already. Oh and yes, it’s VBAT.

    in reply to: Some technical difficulties… Arms folding back in flight #63517
    Kevin_Erik
    Moderator

    Yes, it makes it near impossible to move the arms, without first loosing the supporting screws. Yet, the arms can still move during a crash, which is what you want to happen. Keep in mind that replacing props is easy. Rebuilding an arm assembly takes about an hour, assuming you have the parts on hand.

    Edit: tape could work, but the heat shrink can fits really tight. In the end, i think this is a matter of preference.

    Kevin_Erik
    Moderator

    While Matek makes great FC’s and PDB’s their VTX’s dont fair so well. I’ve had four / five of them, then had one hell of a time gettig a clear video signal. In some cases the VTX is transmitting on the wrong frequency it was set to. (They get really hot)

    IMO, the best combo is the Matek F405 STD / CTR and the FCHUB-W. Both units can stack together and use a ribbon cable to simplifly wiring. Your servo can connect directly to the PDB headder pins without soldering. While the PDB supplies the 6 or 7 volts needed to run it. This makes for a very easy and clean setup. Which is important when you want to add GPS and a high powered VTX later on. Only issue here is that there are only two ESC pads for the motors. Hence you’ll have to double up on one.

Viewing 15 posts - 16 through 30 (of 1,140 total)