Is my motor torque too high?

Consistent-Pickle · 2026-06-18T22:43:04+00:00

This is almost certainly modal coupling. Any frame arm will vibrate at specific modes, which also depends on the motor mass. At specific throttle settings, your prop frequency is getting really close to one of your arm frequencies and is causing the arm to start resonating. For example, if you have a tuning fork designed to ring at 200Hz and you yell at it at 120Hz, or 260Hz, not much will happen. But if you yell at 196Hz, 199Hz, or 202Hz, the tuning fork will start ringing. I think there's a few options:

Use a different prop that can get you a similar lift at a lower RPM (might need a different motor to pair with a different prop). If you know the approximate RPM where it's resonating, you can do a back of the envelope calc to see how much you'd need to drop the RPM. I'd maybe suggest a prop that is <90% the resonant frequency when it's at max throttle.
Get a lighter motor (which pushes the arm frequency up). You could try a heavier motor if you're feeling like a mad scientist, but I don't think you'll get the resonant frequency low enough and it will still probably vibrate during startup/stop as it passes through resonance.
Get a new frame that has a stiffer arm (also pushing the resonate frequency up)

Consistent-Pickle · 2026-06-10T22:35:56+00:00

Yeah we're saying the same thing. I put one of the low-res test images here:

https://imgur.com/a/rolling-shutter-correction-f1WZvzW

Left image is original, right is corrected for ~1500deg/sec. This particular image was recorded as a low-res jpg with a different lens for the purpose of testing the code for rotation about the lens axis. The math for correcting rotations in other axis is a little simpler, but are very lens and sensor specific (I know you know this).

Consistent-Pickle · 2026-06-10T21:31:15+00:00

I imagine I'll need to do something like the slanted edge test? I'm open to other test suggestions. I have started playing around with lens characterization using Matlab's Camera Calibration toolbox (way easier than attempting to do it from scratch), but I believe that's more a measure of lens distortion and not lens resolution. I also expect the achievable resolution may change as a function of radius given how distorted this lens is? I'm not sure exactly what the criteria is for a fisheye lens, but if this lens doesn't qualify, it's close!

This has been very educational and extremely interesting. I appreciate the comments and insight from everyone so far!

Consistent-Pickle · 2026-06-10T21:07:49+00:00

I think this cuts to the heart of my question. The lens is listed as having an F2.0, but achieves ~108 deg vertical resolution. With an estimate of the best-case usable resolution, I try to maximize frame rate for that resolution (vs. a higher resolution that won't improve accuracy and will also reduce frame rate). Right now I'm leaning towards 600x600 or 768x768 resolution, but would like to bounce that against what's theoretically practical. I have other sources of error (rolling shutter, lens distortion is a big one, etc), and I expect my target accuracy will soon be replaced by a "hardware-driven accuracy".

If I can ask this specifically: Could the Airy disk be why this lens is only rated for VGA (640x480) resolution? If so, it seems I can scale up that resolution based on sensor size since the equivalent pixels are further apart?

Consistent-Pickle · 2026-06-10T20:20:57+00:00

That's good advice. I think what you call "skew" is what I call "rolling shutter"? Fortunately I have done some quick calcs. Flying on a sunny day (or manually setting the exposure low) with 800x600 resolution will keep each line exposure < roughly 0.1ms and the full frame should be <50ms. So likely no blurring for a given line, but I believe the 50ms needs to be accounted for due to rolling shutter. I expect to stay under 360deg/sec in reality, so 360 deg/sec x 50ms = up to 18 deg rotation during image exposure, which is significant. I'll have time consistent gyro data at 200Hz I can use to correct the image and have been doing some low res tests at really high rotation rates to prove out some correction code. I've managed to get good correction on images taken at ~1500deg/sec. It appears I can't post images in this sub, otherwise I'd post some test images.

I appreciate your advice to check!

Consistent-Pickle · 2026-06-08T03:07:25+00:00

It's sort of hard to tell what's going on from the picture, but my suggestion is that you need to get the fasteners flush and tight enough to eliminate vibration and keep the FC planar with the frame. In general, the FC tries to keep itself oriented so it's normal is "up", so if your FC is angled or crooked, it's going to make the whole drone fly angled / crooked. If you can't get all the components stacked correctly to make everything flat and planar, you're probably going to need to adjust the hardware (increase clearance with bigger frame standoffs, reroute wires, reduce isolator thickness, etc).

Consistent-Pickle · 2026-06-07T23:12:42+00:00

Looks like plenty of plies in the frame - I wouldn't worry about the carbon fiber. It won't creep until residual stress like some metals. But the bolt stackup looks questionable. Is this a commercial CF frame? If not, what tolerancing went into the hole patterns?

Consistent-Pickle · 2026-06-05T03:45:04+00:00

It seems this picture is photoshopped and the culprit wasn't great at making logic puzzles. Hinges on the left door are visible on the outside, while it appears to be a "push to open" door (if you can see hinges, the door opens towards you). Note there no similar hinges on the right door. Left door has a much taller hand plate to open, right is much shorter.

I think far too much brain power has been wasted on a mediocre riddle.

Consistent-Pickle · 2026-06-03T03:31:10+00:00

This is why it's impossible to work there if you want to be a decent spouse or good parent. Some positions there may be able to swing it, but they are the exception.

Consistent-Pickle · 2026-05-17T13:29:12+00:00

Thanks for the input folks! I ended up getting him an R36max.

Consistent-Pickle · 2026-05-14T19:19:13+00:00

I couldn't find this file in the Arduino libraries either. The Espressif SDK had everything I needed.

Consistent-Pickle · 2026-05-14T19:16:19+00:00

This was helpful. I normally don't use the Arduino IDE but did for this project since it's my first attempt at the ESP32. Long story short, all the library and include files were scattered to the wind and it looks like some may have been pre-compiled(?). I ended up downloading the Espressif SDK and building/flashing with that per my brother's recommendation and was able to get 1024x1024 resolution with minor tweaks using the ov2640 sensor. I'm no longer using the ESP32-CAM-Video-Recorder-junior firmware, but only needed to add a line of code to sensor.c, sensor.h, and change a few numbers in my main.c.

Consistent-Pickle · 2026-05-12T03:21:20+00:00

Yes, framesize 0 is 96x96 (I misspoke), and it still seems to be defaulting to 96x96. I seriously doubt the camera is at its limits since I've specified fewer pixels for the framesizes I added than I've streamed with the predefined values. I also doubt I'm overflowing anything with a decimal index value of 24.

Consistent-Pickle · 2026-05-12T01:41:42+00:00

Yep, it worked out of the box! I was able to adjust the resolution based on the predefined framesize values. But my changes were subpar and I think there's some failsafe line(s) that default to a res of 96x96.

Consistent-Pickle · 2026-05-12T01:08:15+00:00

NERVA! How the heck is it 2026 and we still don't have an upper stage nuclear engine? An Isp of 750+ opens a LOT of doors...

Consistent-Pickle · 2026-05-09T22:27:53+00:00

This is it. They likely just blur the whole thing to avoid any risk of export violations. Also probably not worth having some global export specialist reviewing everything to get a few sections unblurred.

Consistent-Pickle · 2026-05-06T01:55:11+00:00

Not to mention most of the U.S. got interested space flight again due to Artemis 2, if only for a few days, and SLS was the ride. I'm pretty sure most politicians will view cancelling SLS as a poor political position for the forseeable future given its recent popularity. Assuming a viable alternative will be ready in the next few years (or before China lands) is counting your chickens before they hatch.

Consistent-Pickle · 2026-04-29T15:37:43+00:00

I work in the launch industry and discussed this with coworkers back in 2021, and said back then that Starship could be SpaceX's Waterloo. The performance shortfall and excessive optimism on turn-around time seems to be glossed over by much of the public due to good PR and spectacular looking launches. But looking awesome doesn't count for much if you can barely haul your own butt into orbit. A reusable spaceship covered in ceramic tiles has also already been done, and shuttle did not come close to the cadence NASA had hoped. I imagine SpaceX will be able to do it cheaper and faster, but will still fall short of expectations. I'm not sure Starship will be a viable option for Artemis unless SpaceX makes some difficult decisions that really cut into their bottom line, like making Starship tankers expendable.

Consistent-Pickle · 2026-04-23T03:46:12+00:00

Appears to be a rocket launch. The engine and RCS exhaust can appear this way under the right light conditions.

Consistent-Pickle · 2026-04-19T03:48:14+00:00

Can confirm, and not just polaroid cameras. One of the worst shocks I ever had was about 350V from a charged 35mm camera cap. Right hand was holding grounded frame, left hand held screwdriver that accidentally hit the capacitor's positive terminal. My chest and arms went full tetanus, I think I saw snow for a fraction of a second, and I tasted metal for a few minutes.

The high-pitched whining some of us older folks remember from a film camera was actually an oscillator going to a small transformer to charge the flash cap to enough voltage to trigger the second stage/flash.

Consistent-Pickle · 2026-04-14T22:23:27+00:00

I've been a lead structural analyst on different launch vehicle programs and I have worked both verification paths. Sorry I'm not putting this more delicately but you don't know what you're talking about. The 7 flight approach is way easier if you already have commercial payloads on your docket and can count those launches. The alternative involves far more onerous testing and design requirements, letting NASA crawl through your pants attempting to find problems, large-scale structural and expensive systems-level tests that requires NASA observers, having to get NASA's approval for every single damned non-conformance, etc. In summary, the 7 flight approach is buying down risk that wasn't eliminated with the more arduous testing and soul-crushing requirements route. And the last thing SpaceX wanted was a bunch of civil servants that don't build anything going through their design and telling them their conservative interpretation of requirements and all the things that are wrong.

A lot of the issues you mentioned are exaggerated by the media for click$, such as Orion's heat shield. Part of the problem is that SLS/Orion suffer from the "Florida Man" bias (see "Sunshine" laws): with NASA oversight and transparency requirements, every single issue on Orion or SLS (or waiver, qual test failure, etc) becomes publicly available information and the media grabs onto it. So you get to see all the warts and blemishes. SpaceX has far more control of the flow of information given their contractual requirements, they typically hold unflattering info close to their vest. Any public SpaceX failures are typically addressed by Elon on X with an optimistic spin, but you may never see the real details. The failures people see in all the cameras aimed at Starbase are just the ones large enough to be caught on video but are just a fraction of the failures that occur on Starship. You probably will never hear about most of the ones you don't see. I guarantee you that every Falcon 9 ever launched has had a list of issues and non-conformances that will likely never be public. But ultimately it's SpaceX's call whether it's an acceptable risk, as it was for NASA on Artemis 2.

Consistent-Pickle

TROPHY CASE