Very good control, low flying time (those ducted fans use an insane amount of energy like this).

print a slipring

At this rate, HN is responsible for my whole adult education.

  >Not sure if it counts as under-actuated

Generally these aircraft still have three+ actuators, they just replace the rudder with differential spoiler or split elevons. Three actuators, three axes. Same number, so it's not under-actuated.

You're referencing the fact that it's dynamically unstable, and thus needs to be stabilized with a computer. That's a different thing.

You can also have aircraft which are under-actuated yet are dynamically stable. One example is a parafoil, which achieves controlled flight using only two actuators (pull lines).

I'm not super familiar with heavy equipment like dozers and such, but some of them may also have a single motor to pressurize hydraulic fluid and valves to articulate the various pistons. So may be able to make the argument there too

Is there a way to track what's going on in the battle bots community? It was pretty cliche, but battle bots was fun to watch in the 90s/2000s.

> but they are tremendously difficult to steer without computer control.

they are not humanly pilotable without computers. they are inherently unstable.

Only to figure out that the vibration in his drone was due to vibration and it was easily fixed by swapping to rotors that he should've used in the first place. Oh well! Live and learn.

Yep, he mentions the video you linked as well. (Mentioning because I watched the video you linked first.)

I don't think it would be all that useful, give the very way it works (modulating motor speed) - your rotation would not be consistent in speed during even a single turn, which makes exposure times different each frame, and possibly too low.

You absolutely could, and that's exactly how a lot of RC helicopters have been flying around for decades now.

https://www.scribd.com/document/840293339/Lama-V3

Yes. Mine does actually fly though, you can run it for as long as you have juice and make it go where you want it to. This one is not controllable, it is stable but it doesn't really go where it is told to go. Though in the longer term he may be able to fix that, I doubt it will work without at least one additional actuator.

It is possible to get full control with just one motor and one control surface but not with offset payloads.

Yes, servos are motors too. But you'll notice that this drone here is not quite controllable. It is still unstable in flight. It can take off but it is seconds before it runs into something and it is yawing all the time.

It means my eyesight and control/reflexes are shot to the point where I can't fly a drone but my kid is super sharp with this stuff and can do it easily. Drones are fast.

Yes, I’ve spent a couple hours lately asking Gemini about various home improvement topics in fundamental detail. I’ve learned a lot about:

- How to correctly hang a pre-framed door (shim it, tack it in place with 16 gauge nails, and use one wood screw in the top 2 hinges to prevent the door from sagging)

- How to properly adhere MDF trim to the ceiling to hide a closet door track (screw a furring strip or a header board to the studs above the drywall, shim it so it’s level in case the ceiling is uneven, and then nail through the face of the trim into the strip)

- What the difference is between the 27 DAP putties and spackles in the paint aisle (turns out Painters Putty 53 is typically used to hide finish nail holes, because you tend to make a lot of them and can just smoosh it in and level it off with a palette knife!)

The best part about using an LLM for learning new things like that is not having to deal with snarky and snobby comments from the community members involved in them. Thanks to an LLM, I learned how to install, maintain, and winterize an above-ground pool. It's not rocket science, but it was not easy either. I peeked into the forums surrounding the pool communities for help first and they were always so hostile towards newcomers. It's very demotivating when you're excited about something new and half the people that are supposed to be helping you are just rude elitists; completely ruins the whole experience.

For optics through photography (not CCD operation or post processing which are vast subjects themselves) I highly recommend View Camera Technique 7th Edition and Scientific America Image, Object and Illusion as general audience applicable introductions.

MMs have their own set of issues though and calibrating them and knowing how the environment can influence them is a requirement for being able to use them productively.

He leads the video with claims of being the first, and it’s reasonable to expect him to have done sufficient research on that claim. It’s a different claim than what GP thought.

It can be single motor too.

Every gram of weight you remove is another gram of explosive you can add. Also consider the difference in supply lines for aerodynamic surfaces and mechanic parts and motors and servos. If you have four hundred servos, you can make one hundred quadcopters, or four hundred of these things. If you only have one hundred control boards powerful enough to control the single motor design though, you can still only make one hundred. (Tho the quadcopter can lift 4x the weight)

What's interesting is that the Ukrainians are building drones near their front lines because if they build them too far away and ship them in, the game has evolved and those drones are already yesterday's news.

The next iteration is the drones removing those pesky humans from the command chain too :/

You are overly hopeful, I suspect.

A significant portion of Russia's attacks are purely on civilians. Even Ukraine's attacks on RU targets have civilian side casualties.

Terrorism will probably always be a thing.

No arguments here.

I guess the most important thing is to spread the tech then... make it fair at least? (Like this guy is doing)

I think the recent winner of the DARPA life challenge was a 'traditional' single rotor helicopter with tailrotor. The very large disc area of the traditional heli design made it more efficient than quad/hex/octo designs.

https://www.google.com/search?client=firefox-b-d&q=darpa+lif...

I know very little of the field, but aren't there applications where the ability to carry ad hoc payloads doesn't matter? Integrating a fixed sensor suite into the ring and balancing it ahead of time is possible then, right?

And what can be learned from full-scale classical helicopters that frequently carry underhanging payloads?

(I don't at all wanna be the typical HN person who thinks their questions about a field they know nothing about are in any way insightful. I'm just trying to learn.)

> For the life of me I can't find the actuators

F3P indoor planes typically use de-cased linear servos which are flat and tiny. Their control rods are made out of piano wire so thin, there's no way it would show up on video. F3P plane designers go to extremes of miniaturization and weight reduction. F3P isn't the corner of RC 3D aerobatics I play in but it's fun to look at photos of crazy F3P planes and the videos just look... wrong :-). https://www.youtube.com/watch?v=lXD6vbGVROw

Unlike the larger, more powerful rotary servos I typically use which need to be mounted near the plane's center of gravity to maintain balance, F3P esoteric, custom linears are so light they can mount them right next to surface they move. F3P seems largely Euro-centric, but there's a growing scene in NA (https://nsrca.us/index.php/flying/f3pindoorsequencesseparato...) and a sub on RCGroups https://www.rcgroups.com/indoor-pattern-f3p-373/.

These days, quads get all the attention (and blowback) but fixed wing is the OG RC. In recent years, meta-materials + SDR + open source have changed fixed wing dramatically, unlocking breakthroughs leading to some crazy extreme flight envelopes and many sub-specialties. There's dynamic soaring gliders which reach sustained speeds over 400mph from hand launch with no motor, cross country motorless gliders can go a hundred miles from launch, and long-range powered FPV (long range = >25 miles), though lately the first rule of LR-FPV Club is 'Don't talk about LR FPV Club' :-)

Personally, I find outdoor 3D aerobatics and slope soaring to both be extremely fun. Although my 3D aerobats are a bit larger than F3P (~ .8 - 1.2M), they are still very light and quite unlike most RC planes in unexpected ways. My planes can fly low, slow and so close I can just launch and catch them by hand. They are quiet, don't need much space and bother no one. Yet, unlike F3P planes, mine can fly outdoors whether in a large backyard, local park or even the beach. Heading into a hint of breeze, they can slow down until they're just stopped, hanging in the air (which looks odd), then zoom off in a blink at over 30 mph, and they keep flying in high winds that ground most RC planes (in fact, it gets even more fun if you have sufficient skill). Because they all have a thrust-to-weight ratio far above 1:1 they also have pretty insane flight envelopes enabling high-torque and high-G aerobatics far beyond the reach of any full-sized planes at airshows. Yet they only cost ~$50 to $200, take maybe 90 mins of my time to build, and can survive high-speed crashes that would turn most RC planes into confetti (the old joke in RC is they tell newbies who insist on starting with too fast and fragile of a plane, "bring a trash bag for all the pieces").

That all combines to make my corner of RC: fun, cheap, low stress and easy to start yet with endless depth to learn ever-cooler aerobatics. I love doing crazy aerobatics only 3 ft off the ground and 20 ft away yet if I 'dumb-thumb' the plane into the ground, it just bounces - or worst case it's a 5 min repair I can do on the spot while changing batteries. All thanks to cutting-edge materials, new motors, HV Lipos, and tiny servos with crazy high torque. It's also engineering-centric and nerd-friendly - so very unlike the vibe of "Your Dad's RC Plane Club." No balsa wood, gas engines or special flying field needed. My radio transmitter looks like an XBox controller yet is modular, runs open source firmware, BT connects to my phone, has SDR features and can be scripted with Lua. I learn new aerobatics with an open source 3D simulator on my laptop or in VR so I can slow down real-time as I learn.

Here's a 1M wingspan outdoor foamy mixing high-energy and low/slow 3D aerobatics: https://www.youtube.com/watch?v=vgkrVimII1E

This design still requires an additional servo for rotor actuation, so the minimum number of actuators is the same as for a fixed wing (roll and yaw are coupled, so the bare minimum is a single rudder servo).

even with the calibration procedure, i've had nearly no success without going into industrial grade components, and as you point out, it's impractical.

gps also won't give you orientation really anyway, and indeed, is mostly outdoors, and rtk is needed for this resolution but also rather inaccessible to amateurs.

If you're working on indoor navigation, that's very cool, when I used to do it, in my context it was easier because we controlled the environment of the robots (markers on walls of a known colour type stuff). We also explored passive radar type arrangements for picking up wifi repeaters, but it became complicated to eg. ignore bluetooth.

Though in the case of this video, the wii sensor bar style approach seems fine, assuming you control reflections

it's not that easy.

You can run your cylinders in parallel, however that means whichever cylinder has its easiest time moving is going to capture a proportion more share of the power. If things are not perfectly balanced, which in reality they're never going to be, that means the cylinder that needs to work the hardest is going to work the least. And so it's going to take a huge amount of effort to control.

Alternatively, you can run your cylinders in series, however that means that if you're trying to feather one to move slow, all the others are going to have to move slower too.

You end up needing multiple pumps in order to make this work well, but pumps are rather expensive and so that's going to bring your costs up. Plus, multiple pumps mean that you're going to potentially want more power than your motor can deliver.

All the above can be solved with careful engineering. However, engineering is expensive too in order to get this right and it's going to take a lot of work.

Almost everything can be improved by making it cost more.

Or more power ;)