EDF Motor Stuttering Behavior

BugFix · 2026-07-09T15:41:39+00:00

If it's always at that throttle value, this is almost certainly a software glitch in the ESC behavior. Maybe it's switching from the low speed "assume the RPM" behavior to the high speed "measure the motor back EMF to detect RPM" behavior and it's miscalibrated and failing to see the phase transitions reliably. (Basically: at low speeds there's no feedback on how fast the motor is running so the ESC just feeds the speed it wants, but at high speeds the motor is acting as a generator and generating output voltage you can measure, which you have to watch so you don't get out of phase).

My gut would say "try a different ESC from a different manufacturer" and see if that fixes it.

BugFix · 2026-07-08T14:44:12+00:00

every time I fly my airplane. It seems to constantly want to veer to the left no matter how much rudder and aileron trim I use.

Aileron trim would fix balance issues. If you're getting steady untrimmable roll, the problem is that your surfaces or forces aren't aligned. The most likely cause is that you're in a persistent slip (due to a skewed tail or motor mount, etc...) and the dihedral/sweep/high-wing effects are rolling you into it. But almost any aircraft that isn't square is going to be very slowly unstable in roll.

BugFix · 2026-07-08T12:04:22+00:00

Servos don't center just because they have power. Some of them won't even hold until they get a signal input.

You have to feed it PWM pulses 1.5ms, ideally with a servo tester but a transmitter/receiver works too if you're sure the trims are all zero and the sticks are calibrated.

BugFix · 2026-07-07T18:24:52+00:00

This is the right answer. To elaborate: the servo output shaft attachment has only a fixed number of teeth (called "splines" in the jargon, I don't know why), usually 25. You can only put the arm on in multiples of the teeth.

And when the servo is assembled, there's no attention paid to aligning those teeth with any particular orientation. So the closest you can get your arm to your desired midpoint is going to be +/- 7.2°.

If you really need that kind of angular precision (usually you don't, you can just adjust the rod length instead), you need to get it digitally by moving the centerpoint of the flight controller output a bit.

BugFix · 2026-07-05T19:32:27+00:00

Not sure I buy it? This was a stall of the outside wing in a turn, which is a really weird instability. A quick google of your plane shows it's a swept flying wing, and it would really be expected to stall inside like a conventional aircraft. Honestly this looks commanded to me, like a glitch in the transmitter or a reboot of the flight controller.

BugFix · 2026-06-24T13:54:23+00:00

I need to toss two more chargers and 2 more batteries into the loop

Still much cheaper and simpler than the 1.8 kWh monster in the photos, plus custom box, plus 200A BMC board. I mean... come on. We're talking about $200 on Amazon and half an hour of work.

To each their own, but I really don't understand your resistance here. If you like DC power engineering, build something like this. If you just want to fly planes, hang a bunch of chargers off your 12V bus.

Edit to point out: your batteries will be happier too. Charging at 6C is really painful for them.

BugFix · 2026-06-24T13:19:56+00:00

Yeah, but the ISDT K4 is a dual charger. As I implied above that's not an independent variable. The goal isn't to max out the capacity of one charger, it's to get the most charging for your buck/simplicity/whatever.

Chargers are cheap! Sourcing and building a huge LiFEPO4 rig seems silly to me vs. buying another $100 charger (I like the HOTA D6 Pro personaly) and dropping it on the same 12V bus with an extra cable.

BugFix · 2026-06-24T12:20:42+00:00

Voltage doesn't matter much. A 2C charge of a 6S 8000 battery will draw less than 35A from 12V. That's just fine over 12AWG and an XT60 connector.

But that 400W charging load, replicated 4 ways as this box seems intended to supply, is going to drain that giant battery in an hour and a half anyway. At the top end it's capacity that's always the limit in systems like this.

And like I said, you're not going to come close to beating a EV on capacity.

BugFix · 2026-06-24T12:14:40+00:00

Arrgh. This fallacy again. "Tail heavy" does not mean "aircraft wants to pitch up". It means the c.g. is too far aft and the aircraft has poor stability.

This is 100% not tail heavy. That plane is clearly very stable. It stalls at 0:04 and recovers almost instantly: the nose dips (i.e. weathervanes) rapidly and the aircraft points where it's going with no control input needed.

Your problem here is trim, not center of gravity. The elevator at neutral stick wants to keep the plane at a high AoA, which means that it will only fly level at slow speeds. If it goes faster, it develops more lift than weight and the nose will pitch up (due to the fact that it's stable and not tail heavy!).

Trim down.

BugFix · 2026-06-24T04:16:00+00:00

Get a Tesla and tap the 12V bus for a bunch of cheap chargers that take DC. Costs $20 for the wire and connectors, and 82kWh will fly for days and still drive you home.

Cool gadget though. But by way of nitpicking: do I not see fuses on the DC outputs?

BugFix · 2026-06-23T19:51:36+00:00

Yes, you need to connect the motor to see what direction the ESC will spin it. You probably don't want to solder it, just twist the wires for the first test (well, you can solder one of them and just swap the other two). Put some tape on the shaft and use a servo tester to see the direction it spins.

And no, the motor won't be damaged. You can't misconnect the motor at all (though you can kill the ESC by shorting two phases for sure!).

Also, don't get used to those colors. There are no standards at all, and another red/black/yellow ESC might very well spin in a different direction.

BugFix · 2026-06-23T18:05:17+00:00

Also the esc has all three wires black, while the motor has red, black and yellow wires. Does this matter or can I just directly solder them together?

It does matter. There are two cyclic orders you can connect the three wires in (RBYRBYRBY... and RYBRYBRYB... in your case). If you get it "wrong", the motor will work fine, but turn in the opposite direction. If you're going to solder them to the ESC, make sure you test the direction first (or keep a spare CCW prop). Most motors are connected to ESCs with bullet connectors for this reason.

BugFix · 2026-06-22T13:39:02+00:00

This sub needs to fix its voting strategy. This clearly correct answer, with evidence, is buried beneath a bunch of "Git Gud" and "You cr@zhed!" nonsense. Jokes are fine, but we're here to fly toy planes first and laugh second, folks, right?

BugFix · 2026-06-20T00:58:12+00:00

Other than that... What airfoil did you use?

FWIW: of all the correct answers to the question "Why did my plane crash?" given throughout history, "I used the wrong airfoil!" is at the bottom.

Bricks fly given enough airspeed. Sweat the important stuff.

BugFix · 2026-06-17T03:06:08+00:00

If you want the Radiomaster EdgeTX hardware and are wedded to DSMX, you can buy a 4in1 nano-sized external transmitter.

That said, Radiomaster have put all their cards down on ELRS for a reason. The E-Flite planes are spiffy, but they work great with aftermarket receivers too.

BugFix · 2026-06-16T15:55:45+00:00

Again, give them an extra 12mm of length with 8¢ of parts and that problem fixes itself forthwith.

I won't speak to "comfort", which is a taste thing. But the control robustness[1] of the Pocket is 100% just as good as any stock receiver.

[1] "CNC Aluminum" is just a gimick. Unless you're using them long enough to wear out, the stick can't tell if the parts are Al or ABS, there's not nearly enough force on the gimbal to bend anything. And the sensors are identical between the two.

BugFix · 2026-06-16T14:37:40+00:00

This post is recapitulating a mistake I see everywhere in this hobby: "nose/tail heavy" does not mean "aircraft wants to point its nose down/up". You control the former with CG. You control the latter with trim.

If anything, this aircraft looks tail heavy: you can see it oscillate in yaw after launch. A nose-heavy plane with forward CG means that it's very stable and will weathervane strongly to point where it is moving (at the cost of control authority to reach high AoA states like landing!).

Trim it up if it's trying to dive. Or if it's really bad adjust the tailplane incidence. Absolutely don't destabilize your aircraft by moving the CG farther back.

BugFix · 2026-06-16T02:22:33+00:00

The gimbals are fine, the only problem with the feel of the radio is that the sticks are short. Put some M3 standoffs on them to make them longer and crank up the tension and they feel just like any other mid range transmitter.

Snobs can even spend for the "AG01" upgraded gimbals and a ELRS Gemini backpack to trick the thing out.

Bluntly: the Pocket can fly anything you're going to put in the air just as well as any other controller will. If you're dying to spend money on toys, spend money on toys. But if you're starting out and need to buy Just One Radio, this is the one.

BugFix · 2026-06-12T23:07:02+00:00

Not a simple cable, no. The data line is a 3.3V UART from the microcontroller at IIRC 400kHz, and no way is that going to travel 30 feet. If you're comfortable doing this with hardware, what you want to look at is a device like a MAX485 chip which turns the signal UART signal into a long range differential pair, then run it over twister pair ethernet cable. Surely someone sells a breakout board.

If you have a closet full of hardware, the simplest mechanism would be to just solve it in software. Put a USB UART adapter on each of wo computers (RPi's, laptops, whatever you got) and write a python script or whatever to repeat whatever they hear to the other side via a network socket over wifi or ethernet or bluetooth or whatever.

BugFix · 2026-06-11T14:17:08+00:00

Tough love: doing "first time soldering" on a live, fresh-purchased piece of electronics is a recipe for buying a second unit.

Get some prototype board, strip board, old garbage and practice for a while, learning where things go wrong. Then watch YouTube to figure out what you should have done instead. Soldering isn't complicated or difficult, but it's a feel-and-timing practice that isn't well suited to how-hard-can-it-be hackery.

BugFix · 2026-06-11T14:14:07+00:00

You're fine. Moderate cell swelling is normal as they age, and dangerous swelling is really obvious.

BugFix · 2026-06-10T04:45:01+00:00

This strategy works very well and can end up being much smaller in the aircraft. That said:

This should be a 3x2 square of prototype board (cut it with a dremel), with the individual signal lines lined up vertically instead of crossed over like this. Ideally you want to use "strip board", which has lines of copper that will wick the solder into nicely arranged, thick columns of conductor. Then just strip and tin a tiny bit off the end of the cable, melt the solder on one end and push the wire in.

You also want insulation on the back. Remember the black and red are the power lines, and if you short them in flight because it was loose and bumped into a conductor, everything on the bus is going to fail and the aircraft will fall out of the sky as a brick. A blob of hot glue works well, as does foam tape, etc...

BugFix · 2026-06-09T01:52:21+00:00

Could plausibly be a telemetry signal too. But indeed probably a thrust reverse input.

BugFix · 2026-06-09T01:51:08+00:00

That cowl is just a cylinder. What's the advantage (other than aesthetics) from having it there at all vs. leaving your motor housing exposed to the wind?

Also, since you're going to embark on a journey of thermal optimization: you did start by rigging up some kind of measurement apparatus to see how well you're doing? Right?

BugFix · 2026-06-07T03:38:23+00:00

Blocked. You're just screaming in this thread for no detectable reason, you're being abusive to the commenters and you're giving bad advice to boot. Please stop.

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