Starting Out

In the last article I gave you a list of items you’ll need in order to get flying, and I talked in-depth about helicopters and engines. In this article I’ll talk you through the radio equipment; servos; and the gyroscope.

Just to recap; the list I gave is:

• Helicopter and engine
• Radio
• Gyro
• Fuel
• Starter
• Glow lead
• ‘Gell cell’ battery and charger
• Fuel pump
• Blade caddy
• Sticks & balls
• Tools & other bits

Radio
So, after sorting-out which heli and engine you’re looking for, you’ll need some radio gear to control it with. Once again there are many on the market, so how can you decide which one’s for you? Well, the first factor I considered was what the other club members were using. I considered this important because I knew I’d want help when learning and I figured that having the same radio transmitter as others would make life easier all round. On my early visits I found that the most prominent transmitter was the Futaba 9CHP (or Field Force 9), but there are a number of JRs and Hitecs too. Now, the FF9 is an expensive beast – more costly than the Sceadu 30 kit (!) – so you may want to think about other options. Just bear the following in-mind when looking (especially if you’re going to purchase mail-order and aren’t getting independent advice first):

• The radio must use the 35MHz frequency – whilst it's legal to use 27MHz radio with aircraft we wouldn't advise it as it's shared with CB radio (NEVER use a 40MHz radio as it is illegal - further frequency information can be seen on the BMFA website**)
• You’ll need at least 6 channels – aileron; elevator; pitch; throttle; rudder; gyro
• You must be able to control pitch and throttle from one stick
• I’d advise being able to programme pitch and throttle curves independently, with at least 3 points on each curve (5 would be better)
• You’ll need 5 servos; all at least capable of the minimum specification set by the helicopter kit’s manufacturer

I think I should just elaborate on that last point about servos. When I bought my radio I got 5 servos in the box, however their torque rating wasn’t good enough for the Sceadu’s pitch mechanism, and I also decided that I needed a faster servo for the tail (I use a ‘heading-hold’ gyro which works best with a fast servo – more of which later ) so I bought better ones. Now, the Sceadu in standard form uses a conventional cyclic and pitch mechanism, but some other heli's use something called eCCPM (electronic cyclic and collective pitch mixing) and it’s very important that you use ‘matched’ servos on these. Matched servos are a set of three or four servos (depending on the eCCPM layout of your model) which all rotate at the same speed and travel as each-other. I think I’ll leave an explanation as to why this is important for someone else – it’s really beyond the scope of the beginners section – suffice to say; if your model’s eCCPM you need matched servos…

In short: I guess I'm saying get a helicopter specific radio and you won’t go far wrong!

Gyro
What’s next? Ah yes, the gyro (or to give its full name: the gyroscope).

As well as being used to change a helicopter’s heading, the tail rotor is used to counteract the natural tendency of the fuselage to rotate in the opposite direction to the main rotor-blades (the ‘torque effect’) – if the rotor-blades are rotating in the clockwise direction the fuselage will tend to rotate counter-clockwise (turning left). We can, and indeed should, set the tail-rotor’s pitch so that it counteracts this torque effect when the model is in a steady hover with the rudder stick in its neutral position. This is fine for a steady hover, but rotor pitch and speed will change constantly throughout any take-off; flight; and landing, and it's rotor pitch and speed that affect the size of the torque effect. In the early days of model heli flying the pilot had to manually counteract the torque effect during flight by moving the rudder stick, which we could still do, but these days we’re spoilt because we can use a gyro.

Essentially the gyro ‘sits’ between the receiver and the tail rotor; ‘listens’ to what we want the tail rotor to do, and then decides how far to change its pitch. If we’re not asking the tail rotor to do anything, either because we’re sitting in the hover or we’re in straight flight, then the gyro will adjust the tail pitch so that the fuselage keeps pointing in the current direction. Bear in-mind that a helicopter is also affected by wind direction – acting just as a weather vane would – so if we’re hovering side-on to the wind, or flying straight backwards, the heli will naturally try to face into the wind or direction of travel. Therefore, not only does the gyro counteract the torque effect, it also has to adjust to the direction of the wind and travel.

Which one to buy then? Well that’s a tricky question to answer. I started with a cheap (about £50) CSM ICG180 which was OK, but my heli still suffered with torque effect which caused me a lot of problems during my early hops. It may have just been my gyro of course, but I never got to find out; as I was fortunate enough to get my hands on a higher spec’ Futaba GY401 ‘heading hold’ gyro! Now, there are lots of ‘heading hold’ (or ‘heading lock’) gyro’s on the market (I’ve heard that the latest CSM SL560 is the ‘dogs sphericals’) and essentially they all claim to be the fastest at sensing and reacting to unwanted direction change – there’s no way your heli will change it’s heading unless you want it to! – which is perfect if you’re learning to hover and you’ve got your hands full enough trying to keep the beast in one-place, let-alone worrying about what the tail’s doing!

So is a gyro essential? – not really, no! There are ways to programme some transmitters with something called ‘revo. mix’, but this is a relatively crude way to set tail rotor pitch and takes a lot of setting-up. We could also learn to fly as the early pilots did; relying on our own skills to control the tail, but since we’re in the beginners section of this website I’d strongly suggest you buy a gyro instead – it’ll help you get into a stable hover much more quickly.

Phew! I know that’s been a bit ‘heavy’ so I’ll leave it there for now. In the next article I’ll work my way through the rest of the list, and maybe tell you about some of the non-essential items too.

I hope you’ve found my articles helpful and informative but, like my flying, I know I can always improve! So why not send us your questions or suggestions and we ’ll see what we can do?