Walkera #4

[Ozzyeureka]

OK, I have tried to fly this thing and it is a pig! I lost control so quickly I hit some stairs and broke one of the padles from the fly bar, by breaking the flybar! But I didnt hit or damage the rotors, thats how fast it went into the stairs.
The main problem I have is that the tail rotor does not start to spin up until the main rotors have taken a lot of weight off the skids, which means the heli is spinning around on its skids.
Then the tail rotor kicks in and the heli either goes over on its side as a torque/gyroscope reaction, or the tail starts to spin in the opposite direction and you have wind a heap of trim in asap.
I have managed three horrible but 'lived to tell the tale' takeoffs with a max altitude of about 6 ft and no forward travel , all had 'power chop' landings. Very ungraceful. I have had about 30 attempted take offs, most were aborted.
Also , the charger is not a peak detection type, nor does it cut off by itself so watch the battery carefully, or better feel the battery every 20 minutes and when it gets hot, stop the charging, or get a better charger.
And the NiMh batteries are rubbish. Very heavy, low in capacity and barely enough to let the heli fly at all. I owuld suggest you go for the 11.1V LiPo option battery and a decent 3 cell LiPo charger straight up.
The tail rotor issue is because it is a 3 pole armature in a very strong feild and so it cogs quite strongly. Because of the cogging, it takes a lot fo volts to get the motor to spin, which is then too high for the job we are asking it to do.
Also the thing vibrates like crazy, even with re balanced main rotors. I think the main gear is unbalanced, I know it is slightly warped.
I like the look of this heli very much , but the implementation is poor.
Only a C- for this one I am afraid.

[skeeve666]

erm i am new here but i have been flying a dragonfly 4 for several months and never encounted the problems you have, the tail always spins up with the main rotor, the tail motor does no cog that much this is basically because your tail motor is stuffed, i have gone though 6 already as they blow easyly, the vibration is due to the paddles been out of alinement spin it up with the main blades removed, and watch them paddles and ajust them, this normaly happens when you replace the flybar, also sounds like you bent the main shaft.

do not get a 11.4v lipo, it will fry the receiver/mixer it is not rated at that voltage a 7.4v is perfect, one of my friends did that.

i agree with the standard charger it screws a battery if your not careful but a semie decent peak charger is not that expensive.

the dragonfly 4 is VERY crash resistant, if you get the training kit, the carbon poles from that will make new flybars and most of the frame (though i have never managed to snap the frame) I have only gone though 2 sets of main and tail blades after dozens of crashes, just remember to kill all power if its going to hit somthing.

these little fixed pitch helis are great to just fly around your house, great for a beginner, the tail can be a bit twitchy but you get used to that, upgrading to a superskids skid mod is well worth it, no i am not a spokeperson but it makes it stronger and more stable on the ground and hard landings.

i give this a B+ the only thing that lets it down is the nafo charger and the low life of the tail motors.

[swatson144]

I don't have a Walkera but I'll address this topic since I do have a couple FPs all from the same roots. I'm very pleased with them and have had much enjoyment from them.

On your tail not starting with the main. It sounds as if you need to adjust the mixer pot to start mixing main to rudder earlier. I know the instructions with the #4 leave much to be desired on this point. 1 pot will adjust the gain (how hard the gyro reacts to a yaw) the other will adjust the mix percentage from main to tail.

On the Nimh. Right on man they'll suck the fun out of it.

On 3s LiPo, I fly all mine on 2s. plenty of power and the motors last very well provided they are carbon brushed. To go with 3s you really need to drop a couple teeth on the main pinion and drop the voltage to the tail motor with a couple series diodes or go Direct Drive with the GWS 12-rxc motor and a 3x2 prop. I have been brushless main and brushed DD tail for a long time now as I got tired of replacing main motors every 10 hrs or so. on the 4n1 3s is a nono and you will be upgrading to seperates sooner than you may want.

I strongly recommend anyone flying these tough little helis put fuses on the motor leads 6A for main 3A for tail to protect the 4n1. If the fuse blows the little buggers just fall with no real damage and it's a lot cheaper than a 50$ 4n1. You stall a motor in grass for a micro second you could blow the 4n1, if a motor goes bad and shorts same.

Serious vibes are almost always caused by a bent main shaft or the flybar not being centered.

If parts are a problem in your location you can replace assemblies with Century GWS or esky parts. If you start mixing parts the GWS or century HB are the best as they exchange amongst themselves on the component level. I have noticed that the ball sizes are different. on the upper swash(#4 V others) . I had a #4 swash laying around and tried to install it on a HBird I just wound up swapping the upper swash so the same would work backwards.

Some info on my favorite and a couple vids are in this thread http://www.helitown.com/forum/viewtopic.php?t=91 These all came from the same exact heli (which was a semi clone of the piccolo) and have diverged a bit from it but nothing significant.

Steve

[skeeve666]

trouble is with a #4 the main pinion there is only one size and the motor pinion is fixed too ;[ so sticking to the 2 cell is a very good idea

i have tried the tried going direct drive on teh tail with a 3x2 prop, but it spins WAY too fast and is VERY easy to break if your tial hits ground for a split second.. i went though 6 blades then i went back to a standard drive, even tried duel motor drive with its pointless weight.

the #4 4in1 only has ajustment for the gyro senstivity, there is no mixing ajustment for the mixing ;[ its just a bad tail motor as the coging says. my carbon ones are near smooth.

that idea about the parts is interesting.. along with the fuses.

can you sugest any good parts that perform better than the standard?

[swatson144]

The stock parts are fine. I only mention it because spares can sometimes be hard to find. The swash on the #4 is a good one with the ball in swash already there.

The pinions can be removed and any 2mm .5 mod pinions will replace it. I used to use my drill press as a press until I broke down and bought a pinion puller. I still use the drill press and a slotted piece of metal if the pinion puller won't fit behind the pinion.

DD on 2s I use the 4.5x3.5 props cut down to about 3" and a gws IPS adapter. those props are much stronger and the same price. Looks like this in my implementation. works pretty darn good. The tail props are a strange thing I can replace them in each crash for a couple times and then get 20-30 crashes no problem :? .

Steve

[skeeve666]

yup thats teh motor and prob i used, but they spin too fast for a crash into a chair or tree, glad you had no problems but after the 10th prob i went back to a single geared setup £3 uk for a motor is alot cheaper than blades.

[swatson144]

If you used 3x2" it can't be the same prop since that was a cut down 4.5x3. :wink: The 3x2" has a very tiny hub for pressing on the shaft directly and very small blade roots. They break just looking at them. The 4.5x3 is much stronger.
on the left is the 3x2" middle is a 4.5x3" R is a cut down 4.5x30 (4530) that was bent, in a tail in crash and replaced.

Just to avoid confusion.

Steve

[skeeve666]

the blades i used were the center one, thanks for clearing that up for me.

it did perform well but i tend to have alot of tail strikes, so the cost overid the effectivness of the setup, that and i have no model shops near me so it was all mail order

[Ozzyeureka]

Hmmm, So the other Helis I have checked have the same tail rotor problem?

Main blades are balanced and in balance within .01 of a gram of each other, that should be close enough!

The fly bar paddles are equidistant from tthe hub centre and track the same and have the same angle of attack as best as I can measure ( I used a laser level to get an even line to reference from)

The main shaft does not look to be bent, I rolled it on my glass table .
So it seems I will need to fit one of my spare main gears now.

I found an online supplier of parts for the heli here in Australia. I ordered my parts Sunday night, they arrived by mail Tuesday some time. Thats not too shabby at all. Along with the email notifications of my order's status and follow ups, I am impressed. That is the sort of service that gets my follow on business. And the price was not bad at all.
2 X main gear sets, 2 x main rotor sets, 2 x tail rotors, flybar rod, main rotor connecting piece and mailing, grand total of $65 Australian, about $30 US. I can live with that.

And yes, my 4 in 1 has only one adjustment, I am not sure if it is a gyro gain ( I think it is) or a mixer control. Anyway, have to fix the heli first!

[jgarrett]

If I were to upgrade my #4 by getting rid of the 3 in 1.. I assume I would have to have a receiver, ESC and gyro. What have some of you that have done this used?? Do I have to use any "mix" for tail??? Also what size main motor if I go brushless??? If brushless can I use stock gearing??(will use 2s LiPo) I have had mine for several months and really like it.. I fly larger gas helis and this little fellow gives me a stress break. When I wear it out I will most likely get another or similar. One tip on shakes, I found out early on that if you break a main you have to change them in pairs. I tried replacing just the one broken blade and even though they weighed the same and had the same pitch it still shook untill I installed the other matched blade.
Thanks,
Julian

[swatson144]

If I were to upgrade my #4 by getting rid of the 3 in 1.. I assume I would have to have a receiver, ESC and gyro. And also you'd need a transmitter as the walkeras are proprietary.

What have some of you that have done this used?? RZ hV2 4200 kv is my favorite, Probably the best deal going at the time is the CC genie. I'm runnih one on my H2, it's over kill on an FP but what a deal. http://www.castlecreations.com/products/geni-25.html. besides pork in a motor where better?

You need mix for tail with a rate gyro.

Steve

[jgarrett]

Thanks Steve, I want to use my regular transmitter anyway as I fly Single Stick normally. What Reciever and ESC do you reccomend???? I had even gone so far as to make the Walkera xmitter single stick.
Thanks,
Julian

[swatson144]

Berg 7 not much bigger than a 4 and not much difference in price, a lot more future proof.

Phoenix 10.

You probably want to go direct drive on the tail.

Steve

[jgarrett]

Steve, I got a error on that link for the motor. Castle did have a close out on a Genie 25 with ESC,..go easy on me with the abbreviations as me being a newbie on the board you are way over my head!!!!
Thanks,
Julian