The Walkera Dragonfly 4 RC helicopter
The Dragonfly 4 from electric rc helicopter manufacturers Walkera is just one of many FP (Fixed Pitch) electric helis that became widely available thanks to the electronic revolution that has changed the face of radio control over the last few years.
Although the DF4 featured on this page is now discontinued, it was hugely popular in its day and gave a fair introduction to flying a radio control helicopter to those who didn't want a collective pitch model.
China is currently the world leader in manufacture and export of rc products, and proper multi-channel radio control helicopters are being turned out in their thousands, at price levels and 'flier-friendliness' that was unthinkable only several years ago.
The Walkera Dragonfly 4 is one such helicopter - a Ready To Fly, 4-channel, fixed pitch [what's FP?] helicopter that can be bought for a very reasonable price. [The EF Sabre and Venom Night Ranger are two examples of 'same heli, different name' and so these pages should apply to those too, if that's what you have.]
Having resisted the temptation to buy such a helicopter for so long, I finally caved and put a Walkera Dragonfly 4 on my list to Santa...
This page is loosely grouped into 5 main sections, which are:
- The purpose of this page.
- The Dragonfly 4 - what you get in the box.
- Setting up the Walkera Dragonfly 4.
- Stop vibration.
- Re-route antenna.
- Helicopter CG.
- Fit heat sinks.
- Fit training skids.
- Final checks.
- Selecting your flying area.
- Switching everything on.
The purpose of this page...
The sole purpose of this page (and the related ones too - see the column to the right) is to help you understand what to expect from a typical 4-channel FP electric helicopter like the Walkera Dragonfly 4.
As already mentioned, there are several similar helis available but I chose the DF4 because of its apparent popularity, its low price and the wide availability of the essential spare parts.
If you have purchased a similar radio control helicopter, or are thinking of doing so in the near future, hopefully the tips and guidelines covered here will help you through your first flights...
Take note - the info and advice offered here may not be 100% accurate to your helicopter if it's not a Dragonfly 4, and it certainly does not apply to more complex collective pitch (CP) electric helicopters! But it should still give you a good idea of what to expect from a 4-channel FP RTF heli, and help you have a safer experience.
It's also important to note that such 4-channel FP electric rc helicopters are not toys! You need to be sensible and responsible with them, especially while learning - spinning blades can do a lot of damage to people and property.
The Walkera Dragonfly 4 - what's in the box
The Walkera Dragonfly 4 rc helicopter is RTF - that stands for Ready To Fly. In other words, everything you need is in the box apart from 8 AA batteries for the transmitter (abbreviated to'Tx').
Some versions may include a training skid kit and Tx to pc cable so that you can use the FMS flight simulator to practice on. Regardless of whether or not you decide to use FMS, the training skids are highly recommended, and in fact pretty much essential for your first flights. If they're not included with the heli, buy a set for a few dollars online.
The Tx is, unsurprisingly, very 'plasticy' but it does the job, and it's fairly typical of all transmitters sold with the lower-end 4-channel RTF electric helicopters these days. You need to purchase 8 AA size batteries to operate it - you can use good quality disposable cells or rechargeables. I used 700mAh NiMH batteries, and there is a charging socket in the back of the Tx that accepts a standard Tx charging jack.
Incidentally, the Tx 8-cell battery holder is removable with a 2-pin JST connector.
The battery level indicator is in the top/center of the Tx face. 10 vertical bars increase in height from left to right and when the Tx is switched on they illuminate over a range of red (left), orange (middle) to green (right). Obviously you want the green to be there - if they stop at orange then your batteries are in borderline condition, and if only the red is showing then you need to replace/fully recharge them.
You'll need to screw the antenna into the top of the Tx body - a fairly straightforward task. No need to get the pliers onto it, just screw it in as tight as you can get it by hand.
Ignore the 2 chrome toggle switches and small button on the face of the Tx, they have no function and are just a reminder that this is a mass-produced transmitter case designed to cover a lot of different models.
On the back of the Tx, along with the charging socket, is the DIN socket for the simulator cable and the DIP (servo reverse) switches. Check with the instructions that they are in the correct positions according to whether the Tx is Mode 1 or 2 - Mode 2 is more probable, with the left stick controlling power/yaw and the right stick controlling fore/aft and left/right cyclic.
Incidentally, the instructions in the box are about as helpful as an ashtray on a motorbike - you'll get better info from these pages ;-)
Below: the Tx front and back. Lower picture shows the illuminated battery charge indicator and the correct position of the DIP switches for the Mode 2 Tx...
The Walkera Dragonfly 4 comes fully assembled and the theory is that all you need to do is straighten out the main rotor blades, charge the motor battery pack (which also powers the receiver and servos) and take to the skies.....DO NOT DO THIS - read through these pages first, and you'll have a much safer experience!!
Setting up the Walkera Dragonfly 4
Above: the Walkera Dragonfly 4 straight out the box and awaiting set-up
Even though the heli is assembled and set up at the factory, there are some things that you need to do first. But before you start, get the battery pack on charge. With the included charger, this should take around 2 1/2 hours (battery pack is 650mAh, charger is 300mA). At 2 1/2 hours feel the pack, it should be warm but not hot.
Tip: buy a second (or 3rd) battery pack if you haven't done so already, and consider getting a Li-Po pack for more power and longer flight times.
Bad vibes, man...
Unfortunately this type of electric rc helicopter comes with bad vibrations as part of the package! These must be stopped, and the first thing to do, while the pack is charging, is to balance the main rotor blades and flybar. Use those two links to visit the two respective pages - the main rotor blade balancing page also shows you how to correctly fit the main rotors into the holder, and the flybar page includes paddle pitch information.
If the blades and/or flybar are out of balance then the helicopter will vibrate during flight, and this only adds to the frustration of learning to control it properly. Minimising any vibration improves the flight performance, so take the time to do it.
Next, re-route the receiver antenna. As supplied, the antenna is wrapped round one of the landing skids - this is fine for very close range operations but you need to extend it out to be sure of a good, strong signal reception for proper outdoor flying as your experience builds.
Before you do re-route the antenna, decide whether or not you're going to fit training skids. Trying to clip the skid attachments onto and over the antenna will prove difficult, and will almost certainly result in serious damage to the antenna insulation. Fitting the training skids before re-routing the antenna is the best option.
A good route for the antenna from the rx is: down the left front leg, along the left skid, up the left rear leg and out along tail boom. Tape it in position just before the point where the tail rotor tip is at its most forward. From here, coil it round the tail boom back towards the canopy, run it down the right rear leg and wind the remaining amount of antenna round the right skid.
Use tape on the tail boom and tape or small bands of heat shrink tubing (don't heat shrink them though!) to hold the antenna in place on the skids...
Whatever you do, don't cut the antenna! This drastically reduces the radio range of the model, with disastrous consequences. Any antenna that is left over, just wrap around the skid as in the picture above.
Helicopter Center of Gravity (CG):
The next very important thing to do is to check the balance of the helicopter itself - a badly balanced heli will be at best difficult to fly, and at worst completely uncontrollable.
The helicopter's center of gravity (CG) is at the main rotor shaft, and its balance is influenced by the position of the battery pack - so you'll have to do this step with the pack in position on the heli.
Rotate the flybar so that it is perpendicular to the fuselage and lift the helicopter off the ground, with the flybar resting on the tips of your two index fingers, one just each side of the rotor head assembly.
Above left: the well balanced Dragonfly 4. Right: add nose ballast if necessary
- in this case a small coin taped in place.
If correctly balanced the helicopter skids will be level or slightly low at the front. If the skids are lower at the back, then slide the battery pack forward until the model hangs level, and don't forget to slide the clear plastic stops hard against the end of the battery cage.
Also at this point, make sure that you've got the rubber band on the cage to prevent the two halves sliding apart.
If, at this point, the battery is as far forward as it will go and the helicopter still hangs with its tail down, add some weight to the nose of the helicopter canopy - small coins, fishing shots or modelling clay make good ballast.
The disadvantage with adding nose-weight is that it adds to the whole weight of the helicopter, which reduces flight times because more power is needed. But, a marginally shorter safe flight is better than an out-of-control one in my opinion!
Fit heat sinks:
Finally, as an option, you might want to consider fitting heat sinks to both motors.
On this kind of rc helicopter, the tail motors especially are prone to burning out and heat sinks are a good way to help prolong the motor life. They clip around the motor body and carry heat away from the motor itself - they're not available for the Walkera Dragonfly 4 specifically but the eSky EK10223 & EK10224 fit the Dragonfly motors, with a tiny amount of bending.
Fit training gear:
Electric rc helicopter training gear is a great idea and definitely worth the few dollars that they cost. They may not look too flattering, but they do prevent possible damage which can result from the helicopter tipping over in a bad landing.
The standard kit includes 4 skids, each one a carbon fiber leg with a plastic ball at the end. There is also a central hub and 4 attachments that clip over the main skids of the helicopter, at the joint of the skid and leg.
Fitting the training skids can be a bit awkward, and is best done on a large flat surface. You might need to play around with which holes work best, and there's a good chance that the tension that appears in the training skid assembly, once it's all together, will bend or twist the main landing gear of the heli. Try and straighten it out if you can, but it's not a big problem if you can't.
Above: how the training skids fit onto the Walkera Dragonfly 4
Once you've done the main setting up as outlined above, just take a minute or two to go over your Walkera Dragonfly 4 rc helicopter and make sure everything looks to be in order. Things to look for include....
- both servos, make sure they are clipped in place securely.
- the 2 tail motor & 2 main motor mounting screws are tight.
- both motors and servos are connected properly.
- the rx crystal is pushed all the way in.
- nothing appears to be disconnected around the rotor head.
- legs & skids aren't about to drop off.
....you get the idea.
Selecting your flying area - be sensible!
Small electric rc helicopters like the Walkera Dragonfly 4 can be flown in larger indoor spaces but there are some important safety issues to consider, and this section will compare the pros and cons of learning to fly indoors and out...
Indoors: the larger area the better, obviously. Ideally somewhere like an empty garage or basement, but a cleared area in a large room is fine for limited first hops.
A smooth, slippery floor is preferable to carpet for your very first steps. This is because initially you don't want to get the helicopter completely airborne, you only want to use enough power to take the weight off the skids. By doing this, you can get used to the controls and skate the heli around the floor using cyclic and yaw.
Indoor practice also means no wind and this is a major advantage.
If you are practising indoors, cover any corners, walls or objects with some kind of padding - various bedding material and cushions are ideal for this. Most electric rc helicopters like the Dragonfly 4 are remarkably robust, but they're not indestructible. Landing skids and rotor blades are very vulnerable to being smashed in a heavy impact, so be warned.
Below is a photo of my living room, Dragonfly 4 ready. Really this space is too small but it's all I had available. With lots of care and common sense, you can just about get away with it...
Outdoors: obviously the big advantage here is space. But as mentioned above, wind is a serious issue and shouldn't be ignored. If you're going to practise outdoors choose a completely calm day, or at most a breeze of no more than a couple of miles per hour.
If you've chosen a grassy area, such as your back lawn, try and find something smooth to lay down - a sheet of plywood or something similar, to create a flat and slippery surface on which to skate the heli around on.
The danger of having your first go outdoors is the temptation to whack open the throttle to get away from the ground. Not good! You might be able to get the helicopter up easily enough, but you're not ready to get it down in a controlled way yet.
Whichever flying area you decide on, fit the training skids before you do anything else.
Switching everything on
OK, with battery pack charged and installed, main blades and flybar balanced, the helicopter itself correctly balanced and training skids fitted it's time to test those nerves!
Here comes the most important tip of all... switch the transmitter on first, and set the throttle stick AND throttle trim fully closed.
I can't stress the importance of this enough, and this gives me the perfect opportunity to moan about connectors between battery pack and receiver...
The helicopter is 'powered up' by connecting the battery pack and receiver leads. This is fine when connecting, but disconnecting can be very awkward if the connectors are a tight fit and especially awkward if your fingertips are sweaty! You end up pulling too hard on the connectors, and then they fly apart and your hand shoots into the servos and rotor head, or the leads come out of the connector. There must be an easier way!
If you power up the helicopter without turning the Tx on first, there's a very good chance that the motor will spring into life - rotor blades start spinning and fingers can get caught up in them. If you've ever hit your fingernail with a hammer, then you'll know the kind of pain that spinning rotor blades can inflict ("How do you think I know that?...").
Turning on the Tx with the throttle stick and trim fully closed before connecting the battery ensures that the main motor of the heli is completely shut down, and the receiver can synchronize with the Tx in the correct order.
Similarly, always disconnect the battery pack before turning off the Tx, for the same reason.
I'm going to repeat this so that it sinks in ;-) NEVER connect the battery pack to the receiver before turning on the transmitter, and ALWAYS disconnect the battery pack before turning off the Tx. Make sure that the throttle stick and trim are fully closed before you connect/disconnect the battery pack - make this second nature!!
OK, if you've followed the advice on this page then you're pretty much ready to go!...
Next....what to expect from your first hops.