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Fragile -By a different Syma Model
on December 12, 2011
This helicopter flew very well - for a while.
Syma makes a number of very slick little helicopters - I have bought several different models for the nephews and relatives, and everyone loves them. This helicopter, the cobra, looks good and flew very well. All of the Symas we tried so far fly extremely well out of the box. The Blackhawk and Chinook flew very well. The challenge with this particular (Cobra) helicopter is the landing gear. After a few crashes, the strut on 1 of the landing gear broke, meaning that on the ground, the helicopter won't stand up perfectly straight. No big deal - right? Wrong. If the helicopter isn't standing up straight, it won't take off straight, and will probably crash into something before it stabilizes. The Blackhawk and Chinook have different landing gear which are more durable.
For those of you who are first time pilots, focus on hovering for your first few flights. Just tweak the controls to try and keep the helicopter in 1 place. If you can master hovering, the rest gets a lot easier.
Syma's mini helicopters are only for indoor use. The problem with flying them outdoors is wind - the smallest puff of a breeze makes the helicpters uncontrolable.
For those of you who don't know much about Syma's RC helicopters, here is how they work:
1. Stabilization: For real helicopters, the tail rotor controls rotation. Without a tail rotor, a real helicopter would be unable to turn, and would actually spin out of control. The motor for the main rotor wants to spin the fuselage in the opposite direction of the rotation of the main propeller. Think about it - if you were to magically "hold" the propeller in place, the fuselage would spin. The motor of a normal helicopter, if left unchecked, would spin the propeller and the fuselage in opposite directions. In real helicopters, the tail rotor counteracts the rotational force that the main rotor applies to the fuselage
With Syma's helicopters (other than the Chinook), they actually have 2 main propellers stacked on top of each other that have blades that are angled differently, and spin in opposite directions. Both propellers provide down force, but also produce torque on the fuselage in opposite directions. This has the effect of keeping the helicopter stable, since the rotational forces of the 2 propellers on the fuselage cancel each other out. Syma's remote controllers come with a "Trim" control knob. This control is used to make sure that the 2 main propellers are spinning at the same RPM. If your helicopter's fuselage spins slightly on takeoff, use the trim knob to true it up.
2. Turning: In order to turn, Syma's helicopters slow down one of the main rotors by a small amount, essentially using the forces described in #1 to rotate the fuselage. Turning for all of Syma's helicopters is very precise once you have them trimmed.
3. Forward/Backward motion - this is controlled by the horizontally aligned tail rotor. To go forward, the tail rotor spins, producing down force, which pushes the tail up. When the tail is up, the main rotors are angled slightly backwards, so the main rotor pushes the helicopter forward. Reverse has the opposite effect. The tail prop pushes the tail down, which angles the thrust of the main rotors slightly forward, which pushes the helicopter backward.
4. Sideways motion (Yaw)- Syma's helicopters don't have any mechanism for tilting the helicopter's roto sideways, so the helicopters have no ability to move side to side. In real helicopters, the main rotor tilts forward/backward, left and right, and this provides the ability for the helicopter to move in pretty much any direction.
This Cobra heli is not as stable in flight as the Chinook or the Blackhawk. It just seems like the helicopter is a little too responsive.
In short, if you are a good pilot, and won't crash, this helicopter is just fine. For my taste, though, the Blackhawk and Chinook are more durable and easier to fly.
One other note - VERY IMPORTANT! This helicopter comes with an additional tail rotor in a plastic baggie. Save it, and put it in a safe place. The tail rotor controls forward and backward motion, and if you lose your tail prop, all you can do is hover.