RC Helicopters Do Amazing Things

April 25, 2010 8:46 PM

Most people consider the remote control helicopter quite intimidating. As a beginner, your first few hovers are pure white-knuckle terror. Thanks to negative pitch, these little helis can fly inverted. And some people can do truly awe-inspiring freestyle routines (this style of flying is called "3D"). Part of the reason they're so intimidating is that nearly every crash is a total writeoff. Keep in mind, these aren't Radio Shack toys; they sometimes kill people

The principles of flight are complex, but mimic full-scale helicopters. Often described as balancing a soccer ball on a broomstick, attaining a hover takes many hours in a simulator (or, here's a free one), and many separate skills. Even after attaining a hover in all orientations, you need hours of airtime before moving to forward flight. And then, there are many advanced tricks that'll take you years to master.

Airframe-only kits start at $200US (with no electronics, engine, or transmitter), and a fully rigged competition-level machine can run you as much as a used car.

Of course, not everybody's into 3D tricks. Some people go all out on scale helicopters. These use a completely different, much more expensive, rotor head system that does away with the standard flybar system so essential for 3D flight. And recently, through the magic of realtime programming and MEMS gyros, you can simply get a computer to substitute for the flybar, bringing RC helicopters well into the realm of magic--as if they weren't already.

posted by Netzapper (27 comments total)

These always call to mind the aerial drones in William Gibson's books. I'm amazed anyone gets in a real helicopter after reading about how difficult they are to control.
posted by mecran01 at 9:02 PM on April 25, 2010

My dad took me to an R/C flying club event when I was about ten. We left when they brought out what he called the "flying saws."
posted by The Potate at 9:18 PM on April 25, 2010 [5 favorites]

I imagine it is so difficult to fly an RC helicopter because you don't have the immediate physical feedback of orientation and acceleration like you would as the pilot of a full size machine. You have to rely completely on visuals, and those controls must be really touchy.
posted by wigner3j at 9:25 PM on April 25, 2010

Great post.

I got into RC helis back when the dominant technology was "nitro" — single cylinder, two-cycle, nitromethane glow engines. They have a great power/weight ratio but are in many other respects a pain in the ass. Lots of noise, oily smoke, perishable fuel, a whole boxful of stuff to get them started … but they worked.

The thing that made electric helis possible was really the introduction of inexpensive lithium-polymer batteries. Before them, your highest energy density was in NiMH cells, and it didn't approach what you'd get out of nitro. But with LiPos, a brushless, and a good solid-state controller (the latter two developments came from RC racecars), suddenly you had something that could compete, or at least come close to closing the gap, with nitro.

So now it's possible to get into helis without screwing around with nitro. You can go there if you want, but you don't have to right out of the gate like you used to. And that lowers the barrier to entry quite a bit, although at least to my knowledge it's still quite a bit higher than fixed-wing RC aircraft.

I put mine away a few years ago when I moved and haven't gotten them back out again, but maybe I'll have to this summer ... I'm sure the technology has moved forward quite a bit though.

It always seemed to me that the next big thing would be putting gyros not only on the yaw (tail rotor), but also on the roll and pitch servos (cyclic), so that you'd get something close to "auto hover" in the absence of operator commands to do something else. The biggest barrier to RC helis for most people, I think, is the perceived difficulty of learning to fly them. The proliferation of high-accuracy 3-axis gyro chips (used in, among other things, the Wiimote) ought to make this much less of a challenge and expense than it would have been ten or even five years ago.
posted by Kadin2048 at 9:31 PM on April 25, 2010 [4 favorites]

I imagine it is so difficult to fly an RC helicopter because you don't have the immediate physical feedback of orientation and acceleration like you would as the pilot of a full size machine. You have to rely completely on visuals, and those controls must be really touchy.

This is precisely true. I didn't feel like filling the FPP with my personal experiences, but it's really the orientation that makes so much of it so difficult. In a simulator, you can usually set the camera view to first-person. In first-person mode, flying the thing (sloppily) is almost trivial. In real life, even a tail-in hover (where all controls are "properly' aligned) is quite difficult and requires absolutely every bit of your attention and concentration. Nose in? I'm not even there yet on the simulator.

As for the controls... you learn pretty quickly to make tiny, quick, smooth movements. It's like boxing with a hummingbird.

My dad took me to an R/C flying club event when I was about ten. We left when they brought out what he called the "flying saws."

Hahah. Although, those two news stories were all I could find of RC helis killing people. There are lots of stories of RC planes killing people.
posted by Netzapper at 9:44 PM on April 25, 2010

I prefer my foam glider, thank you.
posted by RobotVoodooPower at 9:51 PM on April 25, 2010 [1 favorite]

And I'll stay in my club's fiberglass glider myself.

This "flying saw" nomenclature is good, though. I've often thought that we could enhance aviation safety by replacing some of the terms with new, more evocative words. Propeller is a fine word, but perhaps people would be even more careful around a manthresher.
posted by tss at 10:53 PM on April 25, 2010 [11 favorites]

From the ground it's really hard to tell if you're seeing a real helicopter or a mini so I like to fly mine around mobster's homes just to freak'em out.
posted by HTuttle at 10:56 PM on April 25, 2010 [6 favorites]

Don't forget the Helicopter Obstacle Course.
posted by Tenuki at 11:31 PM on April 25, 2010 [3 favorites]

There is nothing like spending a hundred hours or so building a kit that you know you will likely ruin in the first hour or so after it is completed.
posted by caddis at 3:34 AM on April 26, 2010 [2 favorites]

Yeah, the lack of feedback can be really disorientating, especially when it's a fair distance away from you in poor lighting. Combine that with a lack of nose-in control (heli facing you, so left is right etc.), some blustery winds, and things can be a bit nerve-wracking when you're a beginner. Thankfully the twitchy controls are balance by a lot of power that can get you out of trouble, when applied correctly.

I learnt to hover confidently by practicing a few days a week over a month. Still can't nose-in hover, though, which really limits my flying. Need to get a sim and just practice.

I learnt on an Align T-rex 450. Quite small and twitchy for a beginner heli, some say, but I've cart-wheeled that thing along the ground and only broken a skid. The bigger they are, the harder they fall.

Like others say, it's the orientation that is the hardest thing to learn. At least for my dyslexic self. I've raced RC cars before and never had a problem when the car was coming straight on. For helis it's different.


Kadin2048: There are a few flight stability systems around. Some are more basic, while others can turn an RC heli into a UAV.
posted by Soupisgoodfood at 3:35 AM on April 26, 2010

I've been hearing that these RC helis have come way down in price, so I've been half thinking about investigating the possibility of maybe looking into getting one. It takes hours of training just to hover? No thanks.
posted by DU at 4:36 AM on April 26, 2010

If you're Jerry Baber, you can mount a recoilless automatic shotgun to one and sell it to the Pentagon!
posted by clockwork at 4:52 AM on April 26, 2010

You can buy very cheap gyros, both regular and heading lock, these days. I used two of the cheapest ($15 from HobbyKing) to stabilize the roll and pitch axes of a twin-engine RC plane (a Twinstar II) to make a stable camera platform.

It's possible to get into RC for very little these days if you shop online. My 6-ch TX/RX cost $30 and works perfectly.
posted by unSane at 4:53 AM on April 26, 2010

DU: I've been hearing that these RC helis have come way down in price, so I've been half thinking about investigating the possibility of maybe looking into getting one. It takes hours of training just to hover? No thanks.

Whoever's been telling you that is mistaken. You're going to spend probably $1500-2000 getting set up with your first .30-scale nitro, collective-pitch, single rotor heli. That's airframe kit, 5 servos, tail gyro, nitro engine, and receiver. And you'll also need a transmitter and field gear (to start the engine, pump fuel, etc.). But your transmitter (and most field gear) will work with every RC aircraft you ever fly, so you can amortize those costs if you keep with the hobby.

An electric CP helicopter can be obtained, in box with exactly the transmitter you want*, for around $500US--each battery gives you about 5 minutes of flight, charges in 90-120 minutes, and costs around $60.

And as a beginner, you don't want to cheap out. Sloppy gear can be compensated for by an experienced pilot. As a rookie, you want gear that is as close to mechanically perfect as you can afford.

However, what you may have heard is that indoor micro helicopters have been coming down in price. This is absolutely true. this little guy only runs $100--and batteries, providing about 5 minutes of flight apiece, are only $8 and charge in 20 minutes. It's a coaxial helicopter, so it doesn't have a tail rotor, but controls yaw by varying the relative speed of its two rotors.

Coaxials are very easy to fly. They autostabilize if you let go of the sticks, meaning that learning to hover takes only a few minutes. The autostabilization, however, means that they never transition from a hover to forward flight. And they certainly don't fly inverted or do stunts.

Then there's a fixed-pitch single rotor micro, like this one ($150, but the same batteries as the mCX). Still no inverted flight or stunts, but much more challenging to fly. That particular model also autostabilizes, but will also transition to forward flight, and is much more challenging and nimble than the coax I linked above. There are other models that don't autostabilize.

Everybody starts with a coaxial, and nobody really thinks they're going to get bored in a month and drop two grand to get the challenge back.

Go ahead, try it out. I dare you.

*Don't buy the $50 analog transmitter, please. The modern 2.4GHz spread-spectrum digital transmitters/receivers are radically better than any FM or AM transmitter/receiver. The biggest advantage is this: if you're using an oldschool transmitter and flying your heli, and somebody else on the field happens to turn on their transmitter on the same channel, your heli will fall out of the sky--it's called "a shoot down". Hundreds of dollars and days of building and tuning, down the drain because some other asshole flipped a switch. Seriously. Buy digital.
posted by Netzapper at 5:27 AM on April 26, 2010 [3 favorites]

I am always amazed by these video clips. I have not seen these copters in real life, let alone try to fly one.
My friend has one of those indoors flyers, weighs about an ounce. I tried that one day and almost joined the "killers" club.
I guess I'll have to stick to the static models.
posted by Drasher at 5:47 AM on April 26, 2010

My babysitter used to fly RC helis in the street. He killed someone, too, but he did it by stealing an oil truck and running them over at 60 mph while high on LSD.
posted by nevercalm at 6:19 AM on April 26, 2010 [1 favorite]

However, what you may have heard is that indoor micro helicopters have been coming down in price.

Ah yes, you are right.

Everybody starts with a coaxial, and nobody really thinks they're going to get bored in a month and drop two grand to get the challenge back.

I had some kind of hovercrafty thing that hovered only and it was boring after just a few days. That said, there's no way in hell I'd spend $2k on a toy like this (and if I somehow did it drunk or whatever, my wife would kill me).

The fixed pitch thing sounds neat, though....but we are still talking about only unidirectional flight, right? Or I guess a vertical plane of flight: up and down and forward? No, I guess not because of the tail rotor. But I see the coax also will move forward and turn, so I guess I have no idea what "never transition from a hover to forward flight" means.
posted by DU at 6:54 AM on April 26, 2010

I have a saying: Every Helicopter Pilot, a Helicopter Mechanic.

One of my copters (I have 11 at last count, mostly the small mall ones but 2 Medium ones and a 4 rotor flying platform from ThinkGeek), a E-flight Blade CP, is approaching Washington's Axe level of replacements.

I also have a box of dedicated parts that break most often for repairs.

Finally, those Mall Copters (the big ones) sold by the Israeli conscripts, are not very talented at all. Just scaled up versions of the hand sized minis that are everywhere.
posted by djrock3k at 8:22 AM on April 26, 2010

nevercalm: "My babysitter used to fly RC helis in the street. He killed someone, too, but he did it by stealing an oil truck and running them over at 60 mph while high on LSD."

That, sir, is what I call "Adventures in Babysitting"! (Elisabeth Shue's got nothin' on that guy!)
posted by notsnot at 9:20 AM on April 26, 2010

Computers can fly them too! (Youtube link)
posted by Vulpyne at 9:37 AM on April 26, 2010

Heh.
posted by Mister Moofoo at 9:54 AM on April 26, 2010 [1 favorite]

Holy crap, that hexacopter is wow.
posted by DU at 11:01 AM on April 26, 2010

Dan Shapiro 's Ignite talk is worth a look Geeking out aero-style for a hundred bucks with some ideas how to get started.

Also some lovely footage from a DSLR mounted in a RC heli.
posted by Z303 at 3:10 PM on April 26, 2010

I can attest that even the little cheapo mall ones, hover-only, etc are pretty fun.
posted by LobsterMitten at 4:10 PM on April 26, 2010

yeah, but you can'tcut anybody's head off with one of those.
posted by caddis at 5:19 PM on April 26, 2010

caddis: sounds like you want a Yamaha RMAX
posted by Soupisgoodfood at 10:14 PM on April 26, 2010 [1 favorite]