hrwatson68

Hello all. Even though I have more airplanes(8) than helicopters(1) right now, I still wanted to start this thread to help us poor people who have 4 channel fixed pitch helicopters.

I will post things I have found to help and hope to get help as well on some problems I am having.

One problem I had was that after changing main blades, the heli would'nt achieve lift. I found out that if you give a gentle twist to the mains (give them a bit more pitch), it will lift off again.

I have a glitchy servo problem now. After a hard landing, the servos just twitch at zero stick input. I can move the controls a bit and it stops for a moment but when I try to fly, it starts up again and makes the bird uncontrollable after liftoff. I am going to try some HS-55 Servos I have laing around to see if that helps as I have already moved and adjusted the reciever antenna location.

oops

Walkera 4 forum?

Maybe a Dragonfly forum...

But watch that extra pitch... Walkera 4's have enough out of the box... See if you have enough power or maybe a dead battery cell?

David

hrwatson68

No, both packs were fully charged. The new main blades looked exactly the same as the originals, but it would not lift off, trust me, I changed the main motor and was going to change the speed control next when the guy at the LHS told me to twist the mains, and it worked like a charm, and what's with the question mark about #4?, instead of Dragonfly, that's what Walkera calls it(Model #4). If I just called it Dragonfly, everyone from 6 different manufacturers would be posting here, and Walkera calls all of their helicopters "Dragonfly", so i'd like to keep this forum thread going just with owners of the Walkera #4 helicopter. I realize there are parts from other manufacturers that work on this helicopter i.e. GWS, Century, etc, etc.

hrwatson68

I keep breaking tail rotors because I sometimes slide the tail on my living room carpet(still very green and already tried the parking lot training which resulted in trashing a set of main blades and a tail rotor). Is'nt it ok if I put some sort of extension on the tail stick and just balance the weight with the battery location? I was thinking some sort of skid to help the tail slide sideways instead of the fiberglass/carbon rod (I'm not sure of the composition) just poking it's small toothpick sized footprint down into my carpet.

Also, any ideas on where to find a servo gear set for the #4? If I move the right stick to the full up/right position on the transmitter, one of the servos will grind and click and you'll see the control surface move up and down accordingly

oops

The servo's aren't great... Just replace them. I know it will cost nearly $50, but it's worth it.

I tried HS-55 and they were OK for a while, but are too sensitive to noise for the WK4.

I got some cheap ($22) "Manufactured in China" PFS-09 "Park Flyer R/C Servo's", which have been great. I originally bought them for the tail servo for my Walkera 22a (which flew for the second time today - last flight before I replace the tail gears...). They are good. Very resistant to noise.

Unlike all other servo's I've tried, they don't budge. If you turn the receiver on and off, they remain steady... Not a sound. And since you have center stick when you turn off the transmitter/receiver, they don't move when you turn on either. I literally have to swivel the stick to see them move.

They are a little slow, but fast enough for a WK4. And now I am getting some nice hover... Just dealing with the "Power Cut" problem now... I'm starting to wonder if I have a bad battery connector or maybe a broken aerial wire. Some time I will replace the copper wire with a multicore.

I've gotten mine to take off straight up to a stable hover now. Just add power... But like most Walkera 4's it needs constant attention.
Still I've flown it inside for the first time... Not bad with just 50cm clearance in four directions. Most flights end in grief, but I've kept it close to
center for a 10 to 12 seconds. You need about 1m to 2m clearance in each direction to fly it inside well.

I went through 10 tail rotors. I always buy one more than I have fitted. (Always keep a spare). The original had longer legs than the cheap replacement tailrotors I get from modelshops. I originally put a wire tail on, fixed in 2 spots, but it eventually got bent out of shape. I only went back to the stick today. I got some 1.2mm wire, folder the end 3mm, and stuck it in the hole next to the motor. Then I bent the end around in a half-circle and hooked the end around the tailstick. It keeps it from moving into the tail-rotor arc. A stick of 1m long 2mm carbon stick is only $8, so get some. You will need it. Make the tail stick a centimeter longer. And run a diagonal wire down the line of the tail flag (which I got rid of anyway) and make the end "Bouncy"

That slowed down the destruction of tail rotors a lot for me! Also, I've thought of gluing the broken hub center from a tail rotor to the bottom of the tailstick.

The Walkera 4 isn't too fussy about CoG. They are close anyway. Moving the battery isn't hard, but a few grams at the tail doesn't matter.

My Main rotors are badly chewed out now from impacts... I'm even starting to wonder if that's causing the Gyro to glitch, but the thing still flies, and
when it's not glitching, it's quite good to fly.

The biggest thing with the Walkera is to fix up the head. Clean up any extra plastic.

Also, you usually need to make the blades tight, and they work much better with a 8cell battery Much longer flying times.

Anyway, my experiences with the Walkera 4 have given me an idea what is needed in a training heli Maybe one day I'll design some simple changes and suggest them to the factories

David

hrwatson68

Thanks oops, that was very informative, and I will start later today on some mods. I like this little helicopter. I have a couple friends even who are thinking of getting one.

mazakari

Good idea this mini forum. The Walkera 4 is a very common heli now and there needs to be a place to turn to when all goes wrong. I should know!!!!
My Walkera 4 went through hell when I was learnig to fly but it always came back for more.

My Walkera as it stands now :
===================

11.1V 800mA LiPo battery - standard motors although both fitted with heat sinks.
Aluminium battery carrier - home made just for my LiPo.
JP Supertec Servo's - your right the ones that come with the heli are cheap and you are best to replace them.
Landing gear of a TRex - heli modded to suit - a lot stronger and looks pretty cool as well.
TRex tail fin - not shown in photo (recent mod)

In the pipeline are Like90 blades and a 7mm conversion tail boom with twin motors to split the current increase from my LiPo.

All these mods have increased the weight of the Heli but because of this it needs a higher head speed to fly and in turn this gives greater stability and more control when flying outside in a breeze. Still too light for a windy day though.



Good luck with you flying and all your mods.

hrwatson68

Mazakari, nice pic! I love the way it looks. My first mod is going to be to replace the servos and learn to fly better. I also want a cool canopy like the airwolf with retracts, or the apache body, but after I learn to fly and not crash.

oops

Hi Mazakari,

Looks nice.

David

mazakari

Thanks guys. It started out as a 99UK pound Heli with the intentions of if I smash it didn't cost much and it would be a lesson well learned. What I have learned is to love this little heli. It doesn't matter what you do to it, it just gets back up for more. Its a stable flyer when set up right and too much fun for so little money.
My heli has been grounded over the weekend due to the head coming off in flight (not the heli's fault - just me trying to see how fast it would go[&:]). I use Twister spares in the UK because it is the nearest heli ' clone '. Unfortunately when I stripped the head down to replaced the main rotor hub ( unfortunate casualty ), when assembling I found the Walkera head doesn't fit the hub. Back to the shops later today for a Twister Head!!!
I should be back up and running later today - and who knows what mods I'll come back with this time!!
The guy in the shop is trying to sell me a TRex. I am buying one so it seems, just bit by bit for my little Walkera.

hrwatson68

Well my #4 is down for a while...

I was testing it today and the main motor just quit...

I disassembled the walkera receiver/gyro/speed control unit and heard a disturbing sound (something small rattling around). Upon further investigation, I found one of the IC's has dropped off the circuit board.

I wanted to try a GWS PHA-01 anyway!

I will post an update after I get the unit.

For the 5 bearings I found in the #4, should I just use a good quality R/C car bearing lube after I clean them?

oops

The Walkera 4 uses a single 4410 transistor, which can handle 8A when they get hot. (Up to 71 degrees C)

These can easily drop off at higher loads, say, 10 amps continuous, and there is no airflow across them.

Solder it back on, then perhaps add a heatsink and some fins, held in by the case with the fins protruding into the airflow.

That should solve that problem.

Also check to see if the motor is binding. Mine barely gets hot, and I've just come in from a 10 minute + hover for the first time...
It was only warm after that.... But if the motor is too tight, it will take more current, and heat the driver a lot more.

Does yours take off and hover just barely under center stick?

David

hrwatson68

My motor gets too hot to touch, that might explain the circuit failure. and yes it starts to lift off a little above center stick.

Now I need a main gear, and I need a tiny iron to solder those pins back on.

oops

You don't need too small a soldering iron. Have a look at the circuit board underneath.

One pin (bottom left hand corner) is the drive, and is just one pin, but the remaining pins on the left side are all soldered together.

Likewise the four pins on the right side are all soldered together.

That might make it easier

Regards
David

hrwatson68

That would make it easier, thanks.

wkb

your motor gets too hot?...well my motor doesnt even get warm after hovering for 7 minuts! heres what you do...take rotor blades off ,lay flat on wood ,cover with sheet of paper .get wiffs iron .set on high and press blades as flat as they will go! hold on for 30 to 40 seconds. about half the pitch comes out. now throw that nmh battery as far as you can! and get a 640 mah kokam 7.4v poly pack. you will need to build a small extension on the front to move the battery out to get your cg right because it weighs 3 times less than the original!!! my heli jumps in the air at quarter throtle and flys for more than 10 minutes. I also have mods for the head that makes it fly so stable ,I can hover over a 5 gallon pail and land on it! Iv also solved the burnt out tail motor problem. let me know if you guys are interested...happy flying !

hrwatson68

Quit teasing, we are interested in all mods for the #4. I just ordered a new main gear, so I will be back up soon, after I get a GWS PHA-01 Mixer/Controller. I followed oops advice on trying to fix the walkera unit, but soldering the IC back on did'nt fix it. I have a GWS reciever and a Pixie 20 speed control and electrfly 10 speed contro. Should I just get an inexpensive Gryo, and use the electrics I already have, or is the GWS PHA-01 controller the way to go to save weight? I do have a JR XP6102 Radio that has heli mixes built in and it's programmable. I was going to try to use some stock HS-55 servos I had laying around as well, seeing the stockers have both stripped out.

Are you sure about taking pitch out of the blades??????? I had to twist them more to achieve lift. Maybe the reason I had to increase pitch was because of the poor gear mesh which was overheating the main motor and slowing the rotor head speed down?

wkb

with the 640 mah poly pack its so light you dont need much pitch, the rotor speed goes up making it more stable and both motor stay cool!yes so cool you dont need a heat sink on the motors. add a 1 ohm resistor in series with the tial motor and they last much longer. If your main motor got real hot I think you may have damaged it replace it, its much cheaper than a new speed control! The original walkera gyro, speed cont reciever unit is not bad at all , I think it has one of the best gyros for the price. the reciever also wont allow interferance to make the heli go crazy....Iv had problems with seprates ,I lost 2 helis when they went to full throtle caused by interferance .

HP03 BlackHawk

I have 2 Walkera #4s one using a 3 cell 11.1v 1050mah Li-po and after the first burnt out tail motor I installed a ducted fan from Heli-Hobby, it works like a charm, was only $17 and keeps me from having to buy tail rotors in bulk. I had to shorten the boom 1.5 inches and stuff the battery in the nose with some foam to balance it but now it works great. The other heli is factory stock and the weirdest thing happened today, I had a servo quit and still had full battery charge so I set it on the ground started to spin the rotor to deplete the charge when I dropped my tx, and picked it up hitting the throttle wide open! The poor thing flopped around violently like a chicken with it's head cut off kicking up dirt and cutting the grass but when I got to it and disconnected the battery I couldn't believe what I was seeing: NO DAMAGE AT ALL!!! Whew...This one is a tuff one that's for sure...

hrwatson68

How about some pictures? I am working on getting my #4 airworthy again.

mazakari

A few more pictures of my Walkera 4 Heli. There are some more mod's in the post as I type but its already changed a little since my last picture.

chench

Hi people. I bought a dragonfly #4 a few weeks ago new off ebay but when it arrived and i tried it out it went to full throttle as soon as i connected it to the battery and very nearly took my fingers off before i got it disconnected. I disconnected the main motor and everything else seems to be okay but when i contacted the seller he said to send it back to china to be looked at and replaced and that'd cost £45 and since it only cost £50 it seems kinda silly. So i thought id turn to you guys and ask if you had anything to suggest?

MaxMilli0n

Hi All, anyone got any ideas on fixing my tail rotor problem.

Basically i have to have full left trim on in order to get a straight flight and even then it still turns left a bit. I though it might be the gyro mixing so i have played around with the 1 screw in the receiver and no luck.

I have lost track on the amount of turns now so cant get it back to center as it seems to just go round forever.

I was thinkin of putting smaller blades on the rear that would possibly solve the problem on cut some off the original

What do you think.. or has anyone solved this problem

BOB

hrwatson68

Ok first question from chench.

You made sure the throttle is all the way down and the trim is centered before hooking up the battery? Another thing to check is the reversing switches on the back of the transmitter, on my radio in order from 1-8 on the dip switches they are 1-on,2-off,3-on,4-on,5-off,-6-off,7-off,8-off.

Now those settings could be different on your radio becuse you are in europe and should'nt your throttle be on the right? (I am in the USA and mine was setup for USA with throttle on the left).

I have since burned out the original speed control/receiver/gyro unit from Walkera and refused to buy another, so I just aquired a GWS 3 in 1 mixer to run the speed control and tail motor mixing duties. I would'nt put much more into your #4 to get it right, but I would recommend that you buy a second #4 and use the first one for parts(It sounds expensive, but if you added all the parts prices up and included shipping costs, you are getting a real deal on the parts heli.


Max, for your question...

I think you maybe have a bad mixer in the control unit and I suggest the same thing for you as I did for chench. Before you pull all your hair out, you are centering the trim before turning the radio system on, right?

I am not an expert on the #4 and I am surely learning every day about it.

oops

I don't think you need to center the tail trim before turning on the Walkera 4.

Going left is strange. At full left trim, the tail won't start until you have a lot of rotor speed up. Strange.

The gyro screw shouldn't affect rate of turn, but then I'm not sure. I think it's more response. Since mine works, I haven't played with it though.

Something may be wrong with your electronics. Might be worth opening the transmitter and checking all is OK

Regards
David