| Helicopter "camera ships": Part 1 | - Heli Cameraships 1 |
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The Bergen Observer EB from http://www.bergenrc.com/Observer.php |
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Helicopters are expensive, hard to fly and have issues with vibrations. So why would anyone want to use one of these things for aerial photography? They are extremely flexible, can lift large loads and don't need a large area for takeoff and landing: that's why. That flexibility comes from their ability to easily hold at various altitudes, which allows many photographs to be taken from each angle ensuring you get what you need. A good pilot can put a helicopter anywhere in the air you want to get pictures from, and can hold it there until you have all the photos you need. Then they can quickly move to another position allowing multiple angles per flight. One of the more debated issues with a helicam system is the camera mount. The mount used has an influence on how the helicopter will hover, fly, land and recover in an emergency. nose into the wind. Some underslung mounts offer full 360 degree pan capability: this way the pilot can always point the helicopter where he wants and the camera can still look the right direction. A nice bonus of the underslung arrangement for the older pilots is that it is easier to see the helicopter and the orientation of the helicopter when flown far away. Underslung mounts can be used for photography as well as video photography. Underslung mounts do have a few downsides to consider, though. In the event of a forced auto or emergency landing the camera mount will take a majority of the force from the landing. Because your camera is below the helicopter it may also be damaged. Landing with an underslung mount should be done with very little, or, no lateral motion, because the helicopter is so high off the ground it is easy to tip over on landing. This is generally not an issue, but should be considered. Some argue that for video to be taken in forward flight a front mount is better suited, but that is arguable.
Front mounts are somewhat more rare to see in use. Bergen makes a gasser with a front mount, the Bergen Observer and DJ of the HeliFreak forums sold many front mounts for the Raptor 50 platform this summer. However, I believe the Raptor front mounts are now out of production. Thanks to DJ many people have made the jump to front mounts using a affordable Raptor and his lightweight front mount. Others have simply built their own custom front mounts to fit their current helicopter. With a front mount it is usually not practical to remove and re-attach it for each job, so this generally means a dedicated photography helicopter. This is not a problem, though, as most people have a dedicated ship they use only for aerial photography work even with a underslung mount. Front mount setups can be lighter than a comparable underslung because you don't have the weight of a full undercarriage. Landings don't need to be as precise and slowed down as with the underslung because you are using the regular landing gear of the helicopter you set it down as you normally would without worry of a tip over. This is especially important when doing an auto rotation as you can maintain some forward speed for the landing. This makes autos somewhat easier with a front mount. Because most front mounts are built into the helicopter frame vibration can be an issue if no dampeners are used. Most front mounts bolt to the frame through vibration isolators to help with this. Since the camera is attached to the front of the helicopter it is not possible to do a 360 degree pan with the camera without the helicopter blocking a portion. Some current designs feature 270 degree of pan and 180 degrees of tilt which allows you do get most shots without moving the helicopter. For video, a 360 degree pan isn't as essential, or, useful, as it is for a person doing photography. One thing that the front mount lacks is the stabilizing effect that the underslung has. While the weight of the mount will help the helicopter in wind and help settle it some it does not have the same effect of the underslung. Conclusion I currently use an underslung mount from Airfoil Helicam and love the flexibility it gives me. I have looked at front mounts but prefer the underslung characteristics for what I am currently doing. My thoughts on the Gas, Electric Nitro DebateThis topic comes up just about anytime someone asks what helicopter they should get to use for aerial photography work. This will be focused on helicopters but many things will carry over to fixed wing platforms. When I asked this question when I first started looking at aerial photography, here is one response I got that pretty much sums it up.
This was very true at the time, however there are some new battery technologies that are making electric a much more cost effective solution. Nitro - Nitro is what most people start with when they get into helicopters. I started with a Raptor 30 6 years ago as did many people at that time. Nitro engines have good power output at the expense of being loud and messy. If you plan on running a nitro cameraship you will need to route the exhaust away from the camera, most people do this with a piece of hose or tail boom. A 50 size nitro ship is a good setup for those looking to use their current helicopter as a helicam for experimenting in the AP world.
Electric - Since the introduction of the Align T-Rex the world of electric helicopters has exploded. Some people are using the cheap and readily availble T-Rex as a small cameraship. The next step up from this would be a Mikado Logo 10 or Thunder Tiger Raptor 50 converted to electric. The Logo 10 will lift around 4 pounds of equipment while the Raptor platform can lift around 6 pounds. The heavy lifters in the electric world are the Mikado Logo 24 Bionic, and the ultimate workhorse, the Maxi-Joker 2, which is built with lifting camera equipment in mind. Over the past year battery technology has come a long way. Lithium batteries are standard for good flight times and enough power to haul camera gear around. The batteries are expensive, can be dangerous if handled improperly. However two new batteries have entered the scene. The batteries built for use in power tool are Emoil and A123, they charge fast are nearly indistructible and are about much cheaper that regular lithium cells. This comes as a weight penalty which means shorter flight times but because you could have 3 or more for the price of one similar lithium it is a trade off many pilots are fine making. Because of these batteries I am currently looking at moving from a large gasser to a Logo 10 setup running A123 cells. Gas (actually petrol) setup because the gasser is an overkill for my work. Turbine - The top end of remote control helicopters. Turbines are very smooth with little vibration, have long run times and can lift more than gassers. However a turbine ship starts around $7,000 vs $1,200 for a gasser. They are relatively new on the scene but those using them seem to love the low vibration and long run times. These ships are generally the same size as a gasser. What I am using The Helicopter - We are using a BergenRC Intrepid Gasser EB swinging 800mm blades which is powered by a stock Zenoah G26 gas engine. We run 5 oz of synthetic oil per gallon of Ozark white gas. The white gas runs clean and doesn't have the smell of regular gasoline. This helicopter is rated for something like 20+ pounds of lifting capability using 810 mm blades. My current camera and mount weigh barely 5 pounds and it flies as if the weight wasn't there. Our total flight weight is right around 20 pounds. It therefore takes a good amount of wind to effect it. I went with this helicopter for lifting capability, flight time and factory support. There is a chance I will be selling this as I plan to switch to an electric setup in the future. The Mount - I currently use an Airfoil Helicam M1 Carbon camera mount. It is an underslung mount with servo operated pan and tilt, roll is dampened by rc car shock and rubber bands. The mount straps right onto the landing gear and works good. I am currently designing my own underslung mount as well as a front mount for the Bergen, I will get into the pros and cons of each in a later post. I went with this mount because I found one used for a good price. When shopping for a mount it is easy to think they overcharge for them but you need to think of the time that went into development and testing the product. The Ground Station - I shoot as a two person team as well as alone on occasion so I needed a flexible ground station. We use the Black Widow A/V flexwav down link which displays what the camera sees on an Audiovox portable DVD player with a 7" screen. Everything is mounted on a tripod so it's easy to move and very flexible. It has worked great so far and I would recommend this to those shooting solo and with a dedicated cameraman. Flight Stabilizer - One of the other tools I use on my camera ship is the Spartan RC AP2000i Flight Stabilizer. It can stabilize the helicopter in a stable hover giving me enough time to frame up shots and communicate with my cameraman. I also use it for shots over 100 ft, I can switch it on and not worry as much about holding a hover. This allows me to focus on orientation and altitude. It has proved to be a worthwhile purchase. My answers to the Ever-Popular: How much can my Heli Lift?I see this on average about twice a month on the various boards, someone is looking at AP and wants to try it with their current Helicopter. People are successfully using everything from small helicopters with 315mm blades to large machines swinging 810mm blades or bigger. Now notice I didn't mention any names there, only blade size. I will be doing this write up based on blade size because that is the determining factor for how much you can lift. This article will be a constant work in progress as I find more information. I will list some helicopters running each size blade so you can easier relate it to your helicopter. The amount you can lift also varies by how much your helicopter weighs without the camera mount and extra fear. Blade size is in millimeters measured from the end of the blade to the bolt hole. Keep in mind these are max or near max weights and the helicopter will auto horribly if fully loaded. Blade Size (mm) - Helicopters - maximum SAFE Lifting Capability notes
The linear regression expression is Max_Weight = 4.43E-6 * area + 0.0576 where Max_Weight is in [kg] and area is in square mm Blade type will play a role here. Symmetric blades will offer the least lift, semi-symmetric will offer more while flat bottom blades will offer the most lift. However, flat bottom will fly badly if there is any wind. Semi-symmetrical blades will fly worse than fully symmetrical blades in a wind. Some people have three sets of blades that they select from depending on the lift needed and the weather conditions. I used standard fully symmetrical blades with good results. These will vary dependent on power setup, gear ratio, head speed, helicopter weight, and so on, but this should give you an idea. Camera Mount WeightsA very commonly asked question on the boards is what the weight is of (insert mount name here). I have emailed the mount manufacturers and this is what I have found. I am still awaiting numbers from some of the manufacturers. Airfoil Helicam - www.airfoilskycam.com
Helicam Solutions - www.helicamsolutions.com
Askman AP - www.askmanap.com
CopterFilms - www.cfcoptercams.com
Photo Higher
- from http://airfoilskycam.com/
M1 CARBON 30 The new 30-50 size mount is based around the M1carbon design but has had the weight reduced for the smaller machines. The unit comes completely assembled with the tilt servo installed along With the all new hydraulic roll dampener. The unit is CNC machine from carbon fiber and 6061 aluminum . It's designed to carry digital cameras along with the downlink system and battery. The unit can be used with most 30-50 size helicopters and is designed to be used so the pilot can also shoot the pictures to eliminate the need for a second person on still pictures shoots like real estate and similar jobs. By installing a second receiver it still allows for the use of a camera man as a typical M1carbon mount is used. This unit incorporates tilt and roll only and does not have a pan function. The dry weight of the mount is 1 7/8 lbs and as seen in the pictures the weight is 4 1/4 lbs to make for an incredibly light system with all your equipment installed. M1 Carbon 30 is $399 plus shipping, including the new roll dampening system.
- from http://www.airfoilskycam.com/minipro1.php The Mount specs you are looking at will let you land or takeoff in any direction and also has the ability to rotate 360 degrees non stop without any wiring problems. We are certified welding and CNC machining almost every part. The mount is made from 6061T6 aluminum and Carbon fiber. The mount also incorporates metal geared servos and the proven clutch release system on the tilt function as well as adjustable "O" ring roll dampening. The servo torque is 8.5 kg on the pan and 4.2 kg on the tilt. The Mini Pro1 has 150 mm of roll compensation along with the 360 degrees of pan and 160 degrees of tilt rotation. The camera head has now been widened to 150 mm to accept more types of cameras. We didn’t cut any corners: the mount ts built as strong as the Pro1 but lighter and smaller. The dry weight of the mount came it at 1.28 kg. The unit in the photograph with the Sony V3 7.2 camera, 770JR PCM receiver with the downlink system all powered by a 780 mAh, 3 cell, LiPo battery came in at 1.76 kg. The mount comes like all of our other mounts completely assembled. The system is designed to be used with any 50 size electric or nitro helicopter. It will also work for some 60 size electric helicopters using LiPo batteries. The price is $599.00 (as on 14 May 2008) plus shipping.
- from http://www.helicamsolutions.com/html/pro60-3x.html Pan, Tilt, and Roll are servo controlled and ready for gyro stabilization. Both the pan and tilt are controlled by modified for 360 degree rotation Futaba 3004 standard servos enclosed in a "patent pending" servo block. With a 5:1 gear ratio, the Pro 60-3X mount gives you incredible control. Pan as slow or fast as you desire. 1/2 inch fiberglass tubing and HDPE industrial plastic make for an extremely light yet strong mount. $499.00 |
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