What’s It Really Take?
Back in November 2009, I posted an article about choosing (radio controlled) helicopters for aerial photography. At the time, I was looking for the cheapest way to get professional quality results for both still and video. Back then, you’d need about $3k worth of helicopter (or more). You’d also need to hire a pilot, or spend a year or more likely two years learning to fly it yourself.
Well, all that’s changed. There are new helicopter designs with ever more sophisticated electronics. The new designs are cheaper, more stable, easier to fly, stay in the air longer, and are safer and easier to repair than “conventional” helicopters. And as digital cameras get smaller and lighter, the loads placed on these helicopters are reduced. This makes it possible to use smaller, less powerful helicopters to get the job done. Sound good? Here are the details…
It’s All In The Computer
As I was building a conventional RC helicopter (an Align TRex 600 ESP) for aerial photography, I was also surfing the web to learn as much as I could about alternative ways to get cameras in the air. One day, I discovered quadcopters (aka quadrocopters). A quadcopter is a type of hovering aircraft that has 4 propellers and 4 motors to drive them. The propellers are often simply bolted onto the motors. There’s no variable pitch as with a conventional helicopter. There often aren’t even any gears or servos in a quadcopter. It’s just 4 motors and a computer to control them. Very simple, very reliable.
A Good Practice Quadcopter
The first quadcopter I encountered was called a Draganflyer V. I quickly snapped up a used one on eBay for about $150. It’s not really powerful enough to lift a camera, but it’s great for learning to fly. Here’s a picture.
Because it is small and light (475 grams without battery), the DraganFlyer is great for practicing in small spaces, even indoors. It doesn’t usually break when you crash it. And when it does break, it’s very cheap and easy to fix (You can get parts from rctoys.com). It’s very stable, but not so stable that it’s too easy to fly. It will definitely help you develop some skill. But it’s way easier to fly than a collective pitch (conventional) helicopter. The propellers are made of soft plastic and geared down (unlike most quads) so they are not spinning fast enough to hurt you if an accident happens.
The Learning Curve for Quadcopters vs. Collective Pitch Helicopters
My other practice helicopter is an E-Flite Blade 400. It’s a conventional, collective pitch helicopter. It’s a b***h to fly and always hours of work after a crash. You can make some hardware and software (in the transmitter) changes to make a Blade 400 more stable and easier to fly. But, and this is a big but, a collective pitch helicopter will never be as stable as a quadcopter. So, quads are inherently better for photography (and beginning flyers).
Here’s the kicker. After about 6 months of flying both quadcopters and collective pitch helicopters, I can fly a quadcopter with confidence. This includes both hovering and flying various patterns. Nothing fancy, but competent basic flying. In the same amount of time, I’m still using training gear on my Blade 400. I can hover it and move it around a little, but I don’t feel that I’ve got it fully under control. I find it very twitchy and difficult to land. I would NOT risk a camera on it.
On the other hand, I had no hesitation strapping a Nikon D90 with a 20mm lens on my quadcopter and test flying it. Friends thought I was crazy. But that’s how predictably a quad flies.
Most expert flyers say it takes the average adult about 2 years to learn to fly a collective pitch helicopter with that level of confidence. That sounds about right to me. It only takes a few months to master a quadcopter. That alone would be a good enough reason to use it for aerial photography.
A Serious Quadcopter
It didn’t take me long to figure out that my time might be better spent building a quadcopter with the same lifting capacity as my TRex 600. Around that time, I discovered the aeroquad.com site. Aeroquad refers to a quadcopter that uses a particular computer and software for stabilization. Here’s some pictures of a quadcopter I built using the Aeroquad computer. (This was NOT a kit, but a home brewed design.)
As you might be able to tell, the airframe of my quad is made from aluminum tubing (actually, TRex 600 tail booms), pvc elbows and other pipe fittings from Home Depot, a plastic project box from Radio Shack, pipe insulation, nylon wire ties, plywood, wire, switches, motors, and connectors from various sources, and even practice golf balls. The quadcopter weighs about 1.7 kilograms without a battery or camera. The distance between motors on the same axis is 32 inches. The total cost to build this quad was about $400 minus the radio gear. That’s roughly $200 for the Aeroquad computer and sensors and $200 for the motors, propellars and airframe. Radio gear varies from around $50 for a transmitter and receiver to around $300.
As it happens, the motors I used (Turnigy 2217, 20 turn 860Kv) are a bit small to match the lifting capacity of the TRex 600. But the difference in the total cost with more powerful motors (and speed controllers) is less than $50. I didn’t have enough experience to know that four 220 watt motors would not quite be enough power to lift a dslr and camera mount. Something around 350 watts is more like it. Here’s a brief video demonstrating the quadcopter with a GoPro HD Video camera on board and a primitive camera mount.
Not Quite Ready for Prime Time
So what’s not to like? There are some issues with the current release (1.71) of the Aeroquad software. The Aeroquad computer and software that I’m using has 3 gyros to stabilitze the helicopter. I also put 3 accelerometers on my computer, but the software doesn’t currently use the accelerometers effectively. The accelerometers could be used to provide a much higher degree of stability than you get with just the gyros.
In the Aeroquad software are experimental versions of heading hold, auto leveling and a high stability mode. I have tried these features and in my opinion they are too buggy to be useful in the current release. Since the aeroquad team is working to correct the flaws, I chose not to modify the code myself. Fortunately, the basic gyro controls work extremely well, so the quad is easy to fly at moderate altitudes. The heading hold, auto leveling and high stability features of the software are likely to be fixed in a near future release. With free software, you must be willing to wait, or go in and fix it yourself. I’ll keep you posted on progress in this area.
What’s Required For Aerial Photography?
To use a quadcopter for photography, you often need to fly at high altitudes, where you can barely see the quad. But when a quadcopter is far away from you, it can get very difficult to tell whether it’s right side up or up side down. It’s just a little + in the distance. I crashed the Draganflyer on more than one occasion because I had a split second of confusion about its orientation. That’s where an auto leveling feature is essential. You want the quad to right itself when you either push a button or just let go of the controls. So whether you can see it or not, you know it’s flying straight and level.
Currently, the Aeroquad software does not stay level if you take your hands off the controls. It will drift and eventually crash. I should mention that the same is true of a conventional helicopter, except that the conventional helicopter will crash a lot faster. So, an auto leveling feature is a MUST.
What’s Nice To Have
In the ‘nice to have’ category is the ability to set the position and altitude and have the helicopter stay hovering in place while you let go of the controls and operate the camera (also by remote control). You need a barometer and a GPS for these two features, and the software to use them.
Will the Aeroquad platform have all these features in the near future? I think probably yes. The Aeroquad group recently merged with a group at DIYDrones.com. The folks at DIYDrones have an autopilot system for planes with all of the features I’ve mentioned and much more. They are currently working with the Aeroquad folks to provide all these features for quadcopters and even conventional helicopters. I expect a release within the next few months. This is especially exciting because this will be open source, public domain software and non-proprietary hardware. The benefits of this approach, not to mention the low cost, will be huge. Stay tuned.
What If I Need A CameraShip Now?
Does having all these stability features sound like a lot to ask? Well, there are systems that have auto leveling, GPS position hold and altitude hold. You push a button and the helicopter stays in position within the accuracy of the GPS unit (a few meters) and the altimeter. You can buy them ready made, or as kits. Or you can just buy the flight control computer (see below) and build your own helicopter around it. The fully assembled and ready to fly versions of these systems are very expensive (often around $10,000). Manufacturers of fully assembled units include www.microdrones.com and www.draganfly.com. Video taken from these helicopters is quite amazing. Check out their sites.
But there is a vendor who sells a very high quality system for a moderate price. We’ll talk about this system next.
MikroKopter quadcopters, hexacopters and octocopters
MikroKopter.de is a German company that makes quadcopters, hexacopters and octocopters (spelled with k’s in German). The US website can be found at mikrokopter.us. It is the brainchild of Holger Buss and Ingo Busker. What got my attention is this amazing video where Holger demonstrates the stability and stunning capabilities of his hexacopter (6 motors). By the way, the unit he’s demonstrating can be purchased in kit form complete for about $1500.
In the video Holger uses a light weight point and shoot for demonstration, though the hexacopter can lift about a 1 kilogram payload. Notice that throughout the demonstration, there’s always a camera mounted underneath flight controller (circular hub in the middle). You may also notice that the airframe of all the MikroKopters is very thin and light. If you want to build a MikroKopter to lift a heavier, professional camera, you need to buy or build a stronger airframe, buy bigger motors, and use the MikroKopter computer and motor controllers in it. I may try this. If I do, I’ll post the results.
The cost of building a MikroKopter from a kit or using their computer ranges from about $600 US to about $2000 US depending on which model you buy and whether you provide your own airframe and motors.
A fellow New York photographer, Anthony Jacobs, has gotten a lot of press with his quadcopter, which is built around the MikroKopter computer. Here’s Jacobs’ video page where you can see how stable his quadcopter is. Nice work.
Make Your Conventional Helicopter Stable
There are several devices you can use to tame your conventional helicopter and make it more stable. One is the Copilot II Flight Stabilizer from FMADirect.com. Another is the Helicommand from Captron.
The Copilot II and Helicommand use completely different approaches to stabilization. The Copilot II uses 6 thermal sensors to orient the helicopter. The Helicommand uses a 3 axis gyro and a low res video camera.
To determine the horizon and orient the helicopter, Copilot II uses 4 sensors that look N,S,E,W, one sensor looks up and another looks straight down. If there are no trees or buildings close to the helicopter, then Copilot II can accurately determine what’s up and down and where the horizon is. When you let go of the controls, it can quickly right an inverted helicopter. It can also hold the helicopter in a hover. But, it can only maintain the helicopter in a specific orientation. It can’t prevent drift. So, if there’s wind, the helicopter will not stay in one place without human control.
The Helicommand, on the other hand, uses a 3-axis gyro to maintain orientation. It also has a small video camera, pointed downward that “looks at” the ground to detect and correct for drift. So, if there’s enough texture to the ground, the helicommand can hover in one place without drift. Another advantage of the helicommand, is that it isn’t affected by nearby trees or buildings. So you can use it anywhere without worrying that it’s going to mistake a tree for the horizon and flip your helicopter over.
I haven’t tested the Helicommand myself. A short review of it can be found here.
The Copilot and the Quad
I have a Copilot II that I’m currently using on a Blade 400. It does a very good job of stabilizing the heli when there’s no trees or houses nearby. I plan to reinstall the Copilot on my quadcopter, to see if that helps the quad stay level when it’s a dot in the sky. I’ll let you know how it works.
We’ve discussed some great options for getting an easy-enough-to-fly helicopter or quadcopter for aerial photography.
- One option is to use Aeroquad or Arducopter computers and software with a home built or kit airframe. The estimated cost of such a project is around $500 for the quadcopter. This option depends on software that has yet to be released, but should be available by Fall, 2010.
- Another option is to build your own airframe and use a MikroKopter computer. This option will probably cost around $800-$1000 US depending on lifting capacity.
- Another attractive option, if you’ve got deeper pockets, is to buy a Mikrokopter kit. They range in price from about $1200-$2000 US. Their airframes are light so you can get flight times of around 30 minutes with a light load.
Post a comment to let us know how your project went.