Someone already wrote a really nice review of this copter so I'll keep this fairly short. First and foremost, if you think you know how to fly helicopters from flying 3ch coaxial helicopters, you don't. Although they have provided you with some of the physics of rotary flight, they've also provided you with a huge comfort level in that they are able to hover continuously. Forget most of that with this one.

A 4ch single rotor is getting the user closer to collective pitch flying will still providing a greater degree of safety via being able to hover for brief periods and with some input from the flyer. More challenging but a lot more fund when you've mastered it. This is a great beginner copter for someone who hopes to progress to 6ch CP and likes to fly outdoors. Most coaxials do very poorly in the wind, this does better. Still not great but able to be confidently flown in 5mph breezes.

The copter itself is very well made IMO. Real hobbyists will probably tell you differently but for the price, it really can't be beat. The transmitter that comes with it has far more features than anything else in this price range with the ability to fly in two modes (slow/fast) that changes all the controls. You can even go in under individual controls and get throw rates and percentages to soften the initial flying - make all those adjustments under the slow setting and use that to train yourself. Don't get impatient trying to figure out all the ideal settings for flying - it took me three battery charges to get it right and even then, I still have to use the minor trim buttons to get it perfect for each flight.

Suggestions: Buy the spare parts kit, either on here or from and overseas supplier and buy an extra tail boom/motor combo as the tail motors are not real durable from what I've read. Personally, I bought a DH 9100 here on Amazon for $45 shipped to use as a parts copter - about 85% of the parts are identical to the 9116 plus you'll get a spare battery. It ends up being about the same as what you'd get from various vendors and plus you'll have all those little screws leftover when you're done and they are extremely nice to have.

Double Horse is never going to produce the highest quality on the market. If you want a more well built unit, get a Walkera but if you think you're eventually going to progress to 6ch, get this and save your big money for the next step up. Durability of this unit hasn't been proven yet, might even be described as a little sketchy if you read the radio control forums. I think some of that is unrealistic expectations that it should fly perfectly right out of the box like your coaxial did - isn't going to happen.

One very strong suggestion - always buy this from Amazon where Amazon is actually doing the fulfillment. Most vendors not selling on Amazon will not take returns unless it's absolutely DOA and you call within a day of it being delivered, even then some will assume it worked and you crashed it and may not be as accommodating as you would like. Amazon has basically a no questions asked return policy where if it is defective, they pay return shipping and the refund is very quick.

UPDATE: Having now flown this copter for many hours, my initial impression remains - great value for the money. I have since learned how to make some mechanical adjustments that allow it fly much better and hover almost hands off. If you join the rcgroupsDOTcom forum, you will find a long thread dedicated to this copter and how to make it fly better than it does out of the box. Basically, when you get into 4ch and above flying, there is no such thing as ready to fly perfectly, they will all need some adjustments. Playing with the sub-menus on the controller really makes a difference in training as you can slowly increase various features as your skills improve and then finally go into the "quick" mode where everything is preset to 100% (although can still be changed).

If you're on the fence about this copter, get it. Unless you are an accomplished flyer already, this will be challenging enough to be be fun and durable enough to put up with amateur mistakes. I've flow it into the house, crashed it onto pavement and even got it trapped under a car upon landing. The blades are unbelievably strong because they have taken a beating. Now that I'm a bit more accomplished, I can see one set of blades lasting for the life of the copter.

Do yourself a favor and order a 900mah battery to replace the one that comes with it. Increased flight times will be the result and it fits perfectly in the existing battery cradle. Little bit heavier so you may have to dial in some forward trim to offset it but that's no big deal.

I purchased my Double Horse 9116 from a seller on Ebay. Got a great deal on it as well ($89.88- current price) with free shipping. I was very pleased with my experience from the Ebay seller.

What's in the box?
You will receive a very nice looking DH9116 4 channel electric helicopter measuring 19.5 inches in length if you stretch the main and tail rotors out front to back and measure tip to tip. It stands 5.5 inches tall if measured from the bottom of the skids to the top of the main rotor assembly. Main rotor length is 15 inches. The DH9116 is fully assembled and ready to fly (after it's charged). You will also receive a four channel, mode 2 radio with a high/low rate switch and four trim buttons. The radio also sports a lighted LCD screen that shows trim and stick positions as well as battery life. The menu button allows for stick reversing and set up for left or right handed flyers. You will also receive a wall charger, plug and manual.

What is "Mode 2":
Mode 2 simply means the radio is set up as follows: The left stick is throttle (altitude up/down) and yaw (left/right rotation), while the right stick is pitch (forward/reverse fly) and roll (left/right fly). Mode 1 radios would basically be the opposite. Mode 2 is the most common radio configuration for leisure and sport flyers in the United States, but mode 1 is generally most popular everywhere else in the world.

Capabilities:
The 9116 is a fully articulated fixed pitch, single rotor helicopter. You can fly up, down, forward, backward, cyclic left fly, cyclic right fly and/or turn (yaw) left or right. Just about every movement a real helicopter can make, the DH9116 can imitate. I have flown mine to nearly 150 ft. high with no issues. It is an extremely robust machine that will take some nasty spills and survive pretty much unscathed. It is also a very powerful, fast and nimble little heli.

Preflight preparation (just info):
I unpacked the helicopter and charged it up. The helicopter should be unplugged from it's battery (red plug on the side) when charging or anytime the helicopter is not in use. Upon powering up the radio, you will hear a series of low tone beeps followed by one high pitched beep. It is suggested that you allow the radio to complete its system checks (beeps) before powering up your helicopter. You must make sure your throttle stick (usually the left one for right handed fliers) is in the down or off position before powering up your helicopter, not because your helicopter will take off unexpectedly, but because it will not communicate with the radio until you do; this is a safety feature designed to keep the helicopter from causing any injury, or launching into the air unexpectedly when you turn it on. Once your radio is ready, it's time to power up the helicopter. Plug in the little red plug on the side, set the helicopter on a level surface and turn the power switch on. After a couple seconds, you will see and hear the servos and main rotor move slightly. If you do not, check the position of the throttle stick on the transmitter. Remember, it must be in the down or off position. Once you see and hear the servo movement, your transmitter and helicopter are communicating. It is important at this point to move the right stick around to check movement of the swashplate servo's. I always run the throttle stick up just enough to start the rotor turning and move it side to side to test the tail rotor response as well. If all is working correctly, you are ready for your maiden flight. Consider your skill level before flying the 9116. Don't be ashamed if you're uncomfortable and have butterflies - that's normal. If you're nervous about your abilities, perhaps you should consider a training kit. It may save your nerves and your 9116. Or, if you have the available funds, investing in a good flight simulator is another way to sharpen and maintain your flying skills before tackling more aggressive four channel and up helicopters. Simulators can range in price from as little as $50.00 on up to over $200 depending on the level of realism you are looking for. The "Realflight 6" simulator is my personal favorite, but there are many good ones on the market. Effortless 4 channel flying doesn't happen overnight, but you will get there with practice.

Maiden flight/indoor flying:
It's first fight was ok, but a little shaky. It flew very slightly to the rear and to the left. I am an experienced pilot, so I started out with the radio on high rate or quick response, which means the servos respond quickly to your input and will operate to their full extent... This can be a bad thing for the novice pilot who may not realize how quickly the helicopter will respond to his or her inputs. This can cause a novice to accidentally throw their helicopter out of control, resulting in a possible crash.
My 9116 required a small amount of trim adjustment to make if fly perfectly indoors, - very stable thanks to its gyro technology. Flying indoors will require a fairly large room, unless you plan on just hovering and yawing one direction or the other.
Note: If you're yawing the helicopter indoors or in a confined area, be prepared!! When you yaw (rotate) one direction or the other, the helicopter will drift one way or the other a bit as the gyro tries to compensate and bring the helicopter back to hover against the forced yaw (rotation) given by the tail rotor. This is perfectly normal, but if you're not expecting it, it can result in panic reaction and overcompensation especially if your transmitter is on "High Rate", which can lead to a horrible crash and the death of millions.

Outdoor flying:
Outdoor flying is fair, but as with the 3 channel coaxial helicopters (that you're probably stepping up from), the 9116 is also a bit susceptible to even a light breeze. With swashplate control and vertical tail rotor, it will fly a lot better outside than the coaxials, but still a little hard to control when it's breezy. Just be prepared if the wind picks up. I have flown the DH9116 in winds as high as 15 mph, but I do not recommend that for the novice pilot as you are constantly fighting hard to keep it in the air and in your flying zone. One mistake in those winds and it's Black Hawk Down all over again! It will, however, fly nicely in 5 mph or less winds with little effort.

Getting it flying right:
If your DH9116 can not be trimmed out to fly and/or hover correctly indoors or with absolutely NO breeze outdoors, then perhaps manual swashplate adjustments or counterweights may be the answer (consult your local hobby shop if you are unsure how to do this). Keep in mind that once you turn off your transmitter, your trim settings will go back to neutral. Taking note of your trim settings before you power down will help you re-adjust them before your next flight.
Note: It is not uncommon (and quite innocent) for inexperienced pilots to not realize how much the slightest breeze can affect his or her RC helicopter. Especially the higher you go. You may not feel any air current at all, but your helicopter surely will and it may float around like a feather in the wind, causing you to wonder "why the heck wont this thing hover or fly straight especially since I've been messing with the trim buttons since I took off??!!" Even though you may feel better for a second or two, don't get upset and throw your transmitter at your helicopter - I've learned that it doesn't help at all! Especially when you realize that it could very well be nothing more than the wind.

Battery life/flying time:
The 9116 that I have flies about 8 to 10 minutes on a full charge, which is good and about average. If you're dying for more air time, removing the canopy to get to the circuit board and unplugging the LED lights can gain you a few more minutes in the air (Not recommended when night flying). Despite the box and ad information claiming about 30 to 40 minutes charging time, it may take up to two hours to fully recharge (Mine did -which seemed like an eternity). Some pilots make a wise decision and opt to buy extra batteries and have them charged and ready to go. Charging time is about normal for ANY electric helicopter of this size.
Note: To extend your batteries overall life, it is wise to allow it to cool down for 20 to 30 minutes after flying before you connect it to your charger. Recharging a hot battery will shorten its life dramatically.

Catastrophic helicopter disaster?
Oh yes, it can happen to you too! Even experienced pilots suffer mishaps. Just don't let it deter you from picking up the pieces and trying again, and again. If you do suffer a severe crash (and you probably will), The most common parts to fail on these helicopters are (but not limited to) the swashplate horns, the inner shaft (looks like a "T") and the connection buckles or "dog bones". Both the main and tail rotors will also take a good beating and may get chipped, scratched or dented if you're just learning to fly. Some models of the Double Horse have interchangeable parts (just info). Expect to break things both on the helicopter and around it - which may upset your spouse! Improper handling or abuse of the 9116 will shorten its life. Although it's a tough little helicopter, it's not indestructible. There is no such thing. The builders of the Titanic thought it was unsinkable, but one big ice cube learnt them didn't it?

Extra Parts:
I felt it wise to purchase extra parts when I ordered my 9116 as there are none included in the box. Parts availability is sketchy at best from suppliers here in the U.S., but getting better. There are a few suppliers that offer the most common parts (Banana Hobby in California), but I found shipping to be a little on the pricey side as most U.S. suppliers only ship via UPS freight. Overseas (Feala.com) is your best bet for parts and reasonable shipping rates. However, research indicates Feala.com is reasonably priced, but one of the slowest shippers of parts. I've ordered parts from Feala for myself and others (for resale) on a few occasions. The fastest I received parts from Feala was 21 days. The slowest was 45 days. So, as indicated, order extra parts early, because if you do break something, you may be enjoying the 9116 as it sits on the shelf while you wait for parts to come from overseas which can take three weeks or more. There are a few overseas sellers on Ebay that offer parts kits that include almost everything I mentioned above and more for around $13.00 (current prices) with free shipping (shipping averages 2 to 3 weeks). There are two variations of these parts kits. You can get it with either a swashplate (#9116-16), OR an inner shaft (#9116-06). So far, I don't think anyone offers a kit that includes both. (update 02/08/12: I have found some bundles now include BOTH parts!!)

Moving on up?
The 9116 is an excellent stepping stone if you are learning to fly RC helicopters and wish to master the 6 channels. Obviously, a 3 channel coaxial is the best way to start; simple, stable and you have a lot of fun while you're learning the basics off RC helicopter control. When you are proficient with the coaxials, moving on to something like the 4 channel 9116 that offers much more control, requiring more pilot involvement and coordination is the next, safest and logical step. It will surely help prepare you for the larger aerobatic 6+ channel nitro or electric models. I've flown large 6 channel helicopters, and I can say I wish I had something like the 9116 when I was just learning!! It would have surely saved me a lot of money and definitely some pride!! LOL!!

Spy-Copter!
The Double Horse 9116 is also a good platform for mounting a keychain video camera on as-well. I did this and got some great high flying aerial video. If you get the camera centered and balanced right, your 9116 will hardly know it's carrying anything at all.

Overview:
The Double Horse 9116 is a reasonably priced, very stable, durable and exciting four channel helicopter to fly. It teaches you the important techniques you will need if you are moving on to larger aircraft without breaking the bank. Great flier indoors (in a large room), but be ready to struggle a with it a bit in breezy conditions outside. There are issues and delays with getting parts from overseas, so order extras when you buy this machine. The worst part about owning a Double Horse 9116 is waiting for it to recharge!

All in all, I highly recommend this helicopter for beginners and experienced pilots alike.

As with all my reviews, the above is only my opinion or observation of an item that I own or have tested. Consider that it is possible that I may have either purchased/tested a faulty unit or an exceptionally good one. Your experience may differ from mine, better or worse. Paying attention to the up or down trend from several reviewers will help you make an educated decision on whether or not the item is for you.
Best of Luck and Happy Flying!!

I have now purchased 4 double horse 9116's but only have 1 left. I still love them. Excellent for beginners they have power speed and agility desired when starting your new hobby. They can take a crash and keep on tickin. I do have one common issue I have found. The remotes tend to randomly short out mid flight and fail to transmit. Typically the throttle disengage failsafe kicks in and the motor turns off until the remote transmits and syncs again a second later. This was not the case for two of my 9116's. When the remote shorted the failsafe didn't kick in and I lost controll of my helo in whatever state it was in when it shorted (turning, accelerating, backing down...) well twice now it was during take off, so a bit heavy on the throttle. So as the remote went in and out I attempted to pre emptively direct it. With less people around I would have just grounded it but I feared I would injure someone. So in and out, up and down I would slowly lose control until both times it was over our pond. This was all in a matter of 10 seconds, it had been flying great for the previous 3 minutes. Well the pond is large enough that as it flew over I could no longer control it and had to worry about property damage and injury. With minimal control over the helo, my only option was to back off the throttle completely hoping it got the signal the next time. It did. On the first helo, the throttle control mosfet shorted so while underwater it discharged. Once I retrieved it and had it above water the throttle was not controlled and the blades smacked me a couple times til I unplugged the battery. The second time the water was too cold so I couldn't swim to get it. It's now in a large ice cube. So end result, remotes short internally and fail to transmit constantly and the throttle disengage failsafe... fails.