WALKERA 22E.   

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I’ve had a Walkera 22E V2 for a little over three months and found that even the latest edition of the manual is just not up to the job. There is plenty of information around the internet but it can be hard to find so I'm  attemptting to record my experiences and try to consolidate the information I have acquired for those who are new to this model helicopter in one place. The lay out of this webpage is not ideal but's the best I could find at the moment so please bear with me.

About me:

I'm an ex-RAF helicopter engineer with experience on Gazel,Wessex and Sea King. I once did some stuff on a Whilwind as well but mentioning that might show my age! I think it's now in a museum.I've been building and playing with models on and off for as long as I can remember and flew RC gliders and a powered model about 16 years ago. I'm relatively new to RC Helicopeter's but I read a lot and have completely stripped my 22E a couple of times now so I think I know my way about now. As for my flying, I've mastered the hover tail and side in and can manage a ragged figure of eight. I've also managed a steady hover at about 30ft which was pretty nerve racking followed by a sweet landing which I was rather pleased with myself about. I suppose I  could claim nearly 200 flights and only two crashes due to poor flying but thats only an estimate. As hard as I try I can't claim to be an expert but I hope I can help out. If there are any glaring mistakes (including the spelling) please let me know, or if you wish to contribute you can drop me an  E-mail here.

walkera22e@zoomshare.com 

Anyway back to the 22E:

The main Walkera Web site is here: http://www.walkera.com/en/?la=en

and the latest 22E manuel is here: http://www.walkera.com/cn/upload/explain/Z322E0104_expe.pdf

I'll put the other links I have in the links tab when I get that far...

 Specifications. 

Main Rotor diameter   550mm

Tail rotor diameter      150mm

Overall length              580mm

Receiver (Rx)       4 in 1 (receiver, speed controller, gyro and mixer)Transmitter (Tx)    6 channel PPM/FM

Stock Motor      370 SD

Tail Motor         N30

Stock battery    Nickel Metalhydride (Ni Mh) 10.8 Volt 650 mAh

All up weight                            374g (including Battery)

Introduction 

The 22E arrives almost ready to fly (ARTF) rather than ready to fly (RTF) according to all the advertising on the box. Ok, it comes with all the parts and equipment to get off the ground right after you have charged the main battery and fitted 8 AA batteries in the transmitter but in reality it isn’t quite that simple. To get the best performance out of it and to make sure that it is safe to fly it is necessary to carry out a few checks. Where do you start? Well everybody wants to fly as soon as possible, right? But first I’d recommend that you try a simulator. There’s plenty available and as usual all have their advantages or disadvantages. I use FMS which I down loaded free from here: http://n.ethz.ch/student/mmoeller/fms/index_e.html

Now it might not be completely accurate or the best graphically but it does give you some idea about what to expect once you get into the air with the real thing and it can be quite fun (and it’s free!). Some people spend hours and hours on these and I think many find they can do stuff on the sim that  they wouldn’t dare try on the real thing. That’s fine but the main lesson here is to learn what each control does and just how difficult it can be. Later on you’ll find that orientation is extremely important and can be improved with simulator time. A bit of sim practice can work wonders and it’s something you can do before you even buy your machine. It might even save you some cash if you find it really isn’t that fun and not for you. It’s also handy for keeping your hand in while you are waiting for spares, the weather or the weekend.  Flying a model helicopter is a little like learning to juggle. But if you drop a ball you are juggling it normally won’t cost you anything. If your model falls, nine times out of ten something will break and not always part of the model! These things bite, and bite hard. The first and most important lesson is SAFETY! They are not toys and are not suitable for kids. Not only do they take quite a bit of looking after and setting up but little fingers in the wrong place can be upsetting to say the least. They also have the tendancy to try tricks and push the bounderies. I know I have two young sons ! Please take care and respect your model for what it really is, a miniature flying machine. When you are flying it is easy to worry about crashing and breaking your helicopter but the bigger risk is to yourself, people and the property around you. It’s not hard to be safe but a few simple rules have to obeyed and I’ll try to incorporate those as we go. 

First things first. 

Now as I’ve already said Walkera claim the 22E will fly straight out of the box. That’s not true. The favorite route as far as I can make out (and I’m guilty as sin) is fill the transmitter with batteries and put the main battery on charge. Fit the training gear and get out to fly as soon as possible. But a warning. The main battery will probably have some charge on it already. These things can get extremely hot whilst they are charging and have to be watched closely. The Walkera Charger has two lights on it. Once you plug a battery into it the green light will come on whether it is plugged into the mains or not. The red light will come on once there is power to the charger. Neither is an indication that the battery is charged, getting to hot or that there is a problem. Over heating your battery is not a good thing as it will reduce it’s life. Leave it too long and it may well explode and spontaneously ignite (this is definitely not good). So once it’s plugged in please keep a watch on it. It will take about 1hr ¼ to 1 ¾  to charge but once it starts to get a little warm disconnect it and the charger at the same time as this can burn out as well if left connected to the mains for any length of time. The charger can also get quite hot, so be carefull. 

Update on Batteries: I've now go my hands on a Li Po (Lythium Polymer) battery and quick charger. Now beware. Once you plug the battery in you get a greenlight. Plug it into the mains and the green turns red.Once the battery is charged it turns back to green ! It's taken some time to figure that out! The results are great. I'm getting almost 3 times the flying time to what I'm used to ! Take care with them though I've seen some terrible photo's and scary vids of these things exploding.

So got the battery on charge? Right how about those 8 AA for the transmitter? You can opt for either regular batteries or re-chargeables. I’d recommend the latter as they tend to be more powerful and will be cheaper in the long run, but regular ones are fine as long as you realise it’s important that the power for your transmitter is always strong. The indicator on the transmitter is just that and cannot be relied on to be very accurate. If your transmitter power fails then your model will become uncontrollable and again this is really not good. I wouldn’t want to be anywhere near a model helicopter that’s allowed to do it’s own thing, they can be unpredictable at the best of times. So keep those batteries fresh. 

Now to the Helicopter itself. These models are massed produced in the far east. The quality of the parts is generally good but the assembly can be dubious. I’d suggest that you dig out or purchase a few tools. It’s nice that Walkera provide a set of Allan keys but a set of watch makers screwdrivers is also a must. Later on a pitch gauge can be a great help and maybe a necessity. A bottle of locktite (non-permanent) and some cyno-acrylate glue (super glue) is also very usefull. Some epoxy glue can also come inhandy and pair of long nosed pliers for those with fingers like pigs' trotters. 

Before you attempt to fly the assembly of the model needs checking. This means having a good look around. Not only because of the build process  but for any possible delivery damage. Helicopters vibrate tremendously which can cause nuts, bolts and screws to come loose. Dire if you are flying, so as you look around it’s not a bad idea to make sure all of these are locked in some way to avoid this. Either using locktight or some other glue and that they are all done up snuggly, but not over tight! Over tight causes stress and reduces life! Walkera do apply what looks like a glue but I found quite a few screws just a little loose and the glue was doing almost nothing. So as you go around give each nut, bolt and screw a try. Remove them one a time and apply locktight if you wish or put a very small drop of cyno or epoxy across the screw/nut joint. Even a little wood glue will do but it takes rather long to dry. Remember that you will almost defiantly have to remove these parts in the future so don’t over do it. Think about the weight as well.

Now the 22E is actually quite simple as helicopters go. The main part of the model is known as the Main Body Frame (pt no. HM022E-010). This is the heart of the machine so to speak, onto which all the important parts are attached. 

HM022E-010 Main Body Frame	The tail boom is attached at the rear by a screw which passes vertically down through the main frame and into the boom itself. It is also held in by a clamping screw and nut which is underneath. It’s worth checking at this point that the tail rotor mounting is in line with the main frame. You can do this by sighting down the tail boom and comparing the angle between the tail rotors' shaft and the main beam. If it is not then remove the screw which runs into the boom and slacken the clamping bolt. Turn the boom until everything is correct retightening the clamp and refitting the screw. Don’t forget to lock them.  Almost in the center of the main beam is the support for the main drive shaft. In here you would find a couple of metal bearings for the main shaft but initially there is no need to strip the model down that far to inspect them.  Also attached to the beam is the motor fixing board. This is a bit of a misnomer as you could attach the motor direct to the main frame, but there would nowhere to hang the battery or the 4-1, either way it is attached by four screws. Two of them run though both the main frame and the motor fixing board into the motor. The other two attach  the rear skid. Check the tightness and locking once again.
HM022E-011 Motor Fixing Board

On the mainframe beam are the servo mountings. These are held on by two screws each. Now the front two on mine are countersunk. Whereas the two rear are not. Although counter sunk screws are fitted to both which is curious. Walkera saving either on different screws or countersinking the servo bracket which I suppose would be a bit awkward. I’d suggest that once you get down to this level repairing or even servicing your model then these should be changed or the bracket countersunk. It’s not good engineering practice as it is. I’ve countersunk mine as I have the tool to do it although you can use a large drill bit being careful not to go too deep. I did find that the screws were only a turn or two into the main beam which is probably OK but not ideal. Countersinking the holes allows them to go deeper into the main frame and strengthen the joint .

Servo Mounts.

Whilst looking at the servo mounts it’s worth checking the two screws that hold each of the servo on. All there, tight and locked? You’ll soon loose control if a servo comes away! If they are loose it will effect the control of the helicopter so this can be important. Tight and locked.

Back to the mainframe beam and you will notice a horn at the front. I've not worked out what this is for other than attaching the 4 in 1 and as the 4 in 1 is held on with a sticky pad and velcro strap I beleive this could be cut off to save a little weight. Weight being quite important to the performance of the machine.

The Motor fixing board as I have mention already holds the battery and the 4 in 1. I've replaced mine with a peice of carbon fiber which although isn't much lighter is 4 times stronger and I've made it slightly longer at the front to give me more room for the Electonic Speed Controller (ESC) operating a brushless motor, but more about that later.

 Now for the moment I’m going to jump the gun quite a long way as there seems to be some interest in setting up the rotor head and the parts involved. 

FLYING CONTROLS. 

Every movement of the helicopter is dependant on the correct function of this system. Movement in any direction up/down left/right, forward/back is a result of pitch being added or removed from the main rotor blades. Now this can get a bit complicated so I’ll try and simplify. Imagine a clock, 12 o’clock is over the nose and 6’ o’clock is over the tail. To fly straight up the pitch on both the blades has to be increased at the same time (collectively). To move forward the pitch is increased at 6 o’clock and reduced at 12. In effect tipping the rotor disc forward (this is the imaginary disc created by the moving blades) and inducing forward flight. Using some of the lift created by the baldes to pull the model forward. The same effect works for left and right and everything in between. Decrease the pitch in the direction you wish to move and increase it on the opposite side. This movement is know as cyclic. So you can see that by the time you have initially increased the pitch to go up and then adjusted it to move around the blades are doing all sorts of things. Combining the movements of collective and cyclic is simply know as mixing and there are two types used on model helicopters. The first is mechanical and involves complicated linkages and the second is electronic which is used on the 22E. This is one of the jobs done by the 4 in 1. So by now you can imagine setting all this up correctly is very important to the behavior of your model.  Although it probably isn't as hard as it sounds.

THE MAIN ROTOR HEAD.  

To start with just a little aside. The 22E comes with a few spare parts. Now these can be rather confusing because they don’t match any of the parts on the model. They cetainly stumped me. The reason for this is that they are for a different style of rotor head and is a throw back from earlier versions of the 22. I’ve read about this different arrangement and it appears from those who have tried it that it is not as good as the latest edition. So those parts could go in the bin unless you want to experiment. Now I’ll start at the bottom of the head as this is where all of the commands going to the rotors start, avoiding the servos’ for the moment. 

THE SWASH PLATE.

HM022E-009 Swashplate Assembly 

The swash plates’ purpose is to translate the movement from the servo motors to the rotor blades. Now the servos’ are fixed and the rotor head is spinning and the swash plate is the part that sorts this out for us. It is in fact split into two parts. The rotating star and the fixed (or non- rotating) star. The fixed star is attached to the servos’ directly by three adjustable control rods. There is also a pin on it that slots into the rear servo holder. This is just a guide and stops the fixed star from spinning along with the top half.

The rotating star has four ball joints on it and all of them are attached to the rotor head itself. Two of them are joined to the fly bar holder via oval links. The other two are connected by adjustable rods to the moving links on the head. Each pair are opposite to each other if you get my meaning.

Both the stars rotate about a brass ball and this joint need to be fairly snug. By that I mean that if it wears (which it probably will over time) the response between the two stars will deteriorate and hence the response of your controls. The top should match the bottom 100% The ball should also be snug against the main shaft as it moves up and down the main shaft. I've put a very small amount of light oil on mine to smoothe the movement both on the ball itself and the main shaft. This should help to reduce the wear on the plate but be warned the oil will tend to pick up dust that only adds to the problem of wear acting like an abrasive.

T  SET ASSEMBLY & T-SHAPED HOLDER

HM-22E-Z-10 T-Shape Holder & HM022E-016 T Set Assembly 

The T  set assembly is the hub of the rotor head and is made of aluminum. These parts attach the rotor head to the main drive shaft and drive it. If you should need to replace them they are available as a combined set or just the T set assembly ( see above). The set also includes two small pins. Now I've had problems with these. I was checking over my model one day and noticed they were both missing! Not good as they guide the flybar holder and hold it at 90 degrees to the main blades. I guess I'd lost them in one of my heavy landings. They won't stop you flying but boy the difference in the flying is remarkable. Because the flybar is free to move backwards and fowards it can add or take away pitch on the blades making it rather unstable! The pins can be replaced with a nice straight piece of paper clip or in my case a couple of broken off drill bits glued into the T shape holder.
I think the only important point to mention here is the grub screw. This should be tight and locked as with everything else but it fits into a flat on the main shaft. If not you are going to have problems.

So how do I set up the head? I’ll try to explain how I do it. I’m not going to claim this is right but it works for me. I hope it works for you and as you go along maybe you can tell me a better way.

Starting with the servos’. 

Preparation.    Unplug both of the motors. We don’t want the head and tail rotor spinning up as you are trying to do this and avoid leaving the battery connected for too long as this can cause things to burn out. Only have it connected while you need it. 

Setting the servos’

We need to first check the position of the servos’. To to do this we need to find their center point so we need power. I reset the PLT and PIT knobs at this point. So make sure the dip switch No. 8 is in the unlocked position (over to the left). Adjust both of the knobs on the TX so they are both at the 12 o’clock position. Re-lock the dip switch No 8. Now make sure all of the controls on the TX are centralised, including the trims. The only one that will be different is the throttle. Set that at zero or it's lowest point. Now plug in the battery and after a moment the servos’ will center themselves. The attached arms should all be at 90 degrees. If not remove the screw in the center of the control arm and move it around on the splines until it is as close as possible. Disconnect the battery! Now check that the three control rods to the swash plate are all equal in length. Mine are 36 mm. I dismantled mine and checked that there was at least 2-3 threads into each plastic ball joint connector. It won’t be good if one falls off! While the control rods are disconnected I check that I can move the swash plate down far enough for the flybar holders’ hub to touch the T assembly. This will enable you to get the maximum amount of positive pitch later on. 

So if the servos’ are all horizontal and all of the control rods are the same length the swash plate should now be level with the model. To check this ideally a spirit level should be used but it’s hard to do unless you can make yourself a fork ended plate that will fit onto the fixed star of the swash plate. There is nothing to adjust on the two oval flybar holder connecting rods form the swash plate but I’d have a look and make sure the ball joints are not worn to the point of being really sloppy. The other two connecting rods to the rotor head should now be checked as being both the same length. Mine are 34 mm. 

So up to the head itself. Switch it all on again and level the servos’. Then switch it off again. You’ll notice that as you tip the fly bar back and forth the rotor pitch follows. Now the blade pitch should match the fly bar. To get this right I measure the distance between the forward and back edges of the blade holder and the bottom edge of the fly bar holder. Move the rotor head so that one of the blades is on one side while you do this. The idea is to get the blade holder parallel with the fly bar holder. To adjust it you have to unclip the short link that is attached to the back of the blade holder. First screw it in all the way reconnect it and check the measurement. I guess that the front of the blade is to low (higher measurement). Remove the link again and unscrew it a few full turns, reconnect and measure again. Keep repeating this until both measurements are the same. Bearing in mind the closest you can get is ½ a turn on the link. Just a quick comment on the threaded rods on these models. You may find that as you unscrew them that one end falls off. This is because one end nearly always rotates easier than the other. What I suggest is that you unscrew each one all the way, remove the metal part and put a little drop of locktite/ glue on one end and screw it about 3 full turns into one of the connectors. This will mean that only one end is used for adjustment and there is enough thread in the other to stop it falling apart. Back to the adjustments. My small links are between 16-17 mm. If you’ve done it right you should be getting the same measurement for both blades. In other words the distance between the front edge of the blade holder and the fly bar is the same as the back edge. The fly bar paddles should be level with the fly bar. But be warned the paddles are aerofoils. Therefore trying to place a flat surface across the top of the whole lot won’t work. When we say they are level we are talking about the cord line. This is the line between the front edge and the trailing edge that goes through the width of the paddle. I’ve been trying to come up with a good way to do this but at the moment I’m stuck with the mark one eyeball. Slacken then grub screw on the metal part of the  paddle and turn it until it is a close as possible. Then grub screw sit in a notch on the fly bar so that’s already done for you, but it also clamps the plastic part of the paddle.

It might be worth mentioning here that all of the moving joints on the model should be “snug” and not loose. Make sure all of them move smoothly in the right direction but are not tight. This will put excess load on the servos’ but the better the join the more stable the model becomes. The blades will move all over the place if they are allowed to and each movement will make the model move so they must be under control. Therefore no slopping joints. The plastic ball joints will wear so it’s worth keeping an eye on them and replacing them if necessary.

Now for next bit a pitch gauge is really useful. It’s quite hard to judge the angle of the blades as again we are dealing with the cord rather than the surface. The other thing I have found to be really good is a small spirit level.

To accurately check the pitch you need to first make the sure the fly bar is level (and not with the table). So with it running front to back we can put a spirit level on top of the head, tip the fly bar until it horizontal. I’ve measured the distance between the fly bar and the tail boom and it comes out at 90mm so if you haven’t got the spirit level this should be a good guide. That’s from the top of the boom to the center of the fly bar, as close to the mounting point as possible. Now while you do the next bits I fix the fly bar at that dimension. A piece of dowel or a broken pencil will do it. Then a little sticky tape to hold it firm. Turn on the electrics and wait for the servos’ to centralize with zero throttle and all the trims central. Turn it all off again. You should now have no pitch on the blades, either positive or negative. This is were the pitch gauge comes in. You might be able to do this fairly well by eye but the gauge is better.

With the fly bar strapped down level I then check the pitch with my pitch gauge. Slide the gauge most of the way up the blade and check the top of the gauge is level with the fly bar. This should give you a reading. To adjust the pitch this time I use the two control rods from the swash plate to link on the head. Adjust the pitch to zero and repeat it with both blades. Now, there is the possibility that you might reduce the amount of movement on the head by doing all this. So with everything turned on (motors still disconnected) I wriggle all of the controls and check that the head isn’t binding. Especially with full collective/throttle. Then do the same thing with the 3D switch in the down position. Making sure the sliding hub on the head is not bottoming out either in it’s top position or bottom.

If it is then remove each of the three links on the fixed star. Turn each one half a turn anti clockwise if it bottoming out on the metal hub or clockwise. Whatever is necessary. But make sure you do the same to each link. Now Walkera say that there should be –1 degree of pitch with the throttle in it’s lowest position. This will tend initially to pin the model on the ground. To set this up it fairly simple after you have done the above. Remove the two small links between the lever and blade holder and lengthen to increase the pitch and shorten to reduce it. If you have set things up as above then you will be reducing this. One ½ turn at a time and the same on both links until you get the correct reading on the pitch gauge.

Because the amount of movement on the servos is fixed there is very little you can do about the maximum pitch. The only way I can see of doing it (unless you have a non stock radio set up and can adjust it...sub trims) is to move the position of the links connected to the servos either inwards or outwards. A few people seem to do this to make the model easier to fly. Shortening the distance from the center of the servo reduces the amount of movement to the head but also reduces the maximum pitch. Walkera say that it should be about 7 degrees. It can be higher although I think that unless you are running with a brushless motor and Lithium batteries the motor will bog. In other words you’ll be trying to make it work too hard and you won’t have the power to maintain head speed.