250 heli build help - copterx 250

[gimbleguy]

awesome

[nflanagin]

Now, this is interesting. I use the HK 850mah which fit. The relative dimensions are:
Turnigy 850mah 3s: 55x25x31 - 73g
Pulse 650mah 4s: 60x31x21 - 74g

Might have to play with the battery tray just a touch or heat expand the canopy nose a little, but they sure seem like they would fit. Only problems is the pulse web site says 7 week ETA.

[Krager]

Man that would be great if that 4S battery fits. I think the 250 is suited more toward 4S anyway. Kind of like the way the 450 size helis went from mostly 3S to mostly 6S over the years. Higher voltage is always better even if you don't need or want high head speeds.

[bazsound]

might have found the not flipping flat issues (hopefully) and possibly tail issues aswell.

I wanted to adjust gyro settings, which means removing the bottom plate to acces the BAR. once i got all the screws undone the frame looked twisted, the frame sides had popped away from the landing skid and were at an angle.

Motor mount looks funny in one corner.... sure enough the motor mount has been bent in the front corner and also has another bend in the side.

damnit...

[bazsound]

Still waiting on my motor mount should have been here yesterday!!!!

oh well atleast the 450 is flying... eh no it needs the TT gears changed!

[bazsound]

250 is alive again~!

New motor mount fitted, screws loctited including motor screws. mesh set perfect.

Definatly sounds quieter now with a non bent motor mount. Just did a quick test hover in the house took of straight up no tipover so no majour vibe issues.

I discovered that 1 of the wires in the sat reciever cable was held on by 1 strand. the cables that come with the lemonrx sats are horrible cheap cables. Ive ordered repalcements from hobbyking for both the 250 and 450. The much nicer ones with flexible cable instead of the hard black cable on the lemon rx ones.

Thge main problem with the lemon rx cable is that they are not crimped correctly, they are only crimped onto the bare wire so theres no strain relief.

[bazsound]

250 is definatly flying infact it might be slightly better than it was before. seems that its flipping much flatter.

however doing rolls are still problematic, i think ive figured out whats happening, seems tail is shifting by about 45 degrees during a right roll. Why??? i have no idea i cant get the tail to really shift much during tic tocs or flips. Its just aileron rolls that funky stuff happens

[myxiplx]

Originally Posted by bazsound

250 is alive again~!

New motor mount fitted, screws loctited including motor screws. mesh set perfect.

Definatly sounds quieter now with a non bent motor mount. Just did a quick test hover in the house took of straight up no tipover so no majour vibe issues.

I discovered that 1 of the wires in the sat reciever cable was held on by 1 strand. the cables that come with the lemonrx sats are horrible cheap cables. Ive ordered repalcements from hobbyking for both the 250 and 450. The much nicer ones with flexible cable instead of the hard black cable on the lemon rx ones.

Thge main problem with the lemon rx cable is that they are not crimped correctly, they are only crimped onto the bare wire so theres no strain relief.

Common with most satellites, Spektrum, Orange or Lemon.

Good advice is to re-enforce the ends with hot glue or shoe glue. It both prevents the wires getting unplugged, and adds as additional strain relief.

[bazsound]

i hot glued the end to give me some flight time while a better sat cable comes.

[bazsound]

4 batteires on the 250 today, getting better at tic tocs, managed to get 4 in a row before it fell apart.

got a solution to my wierd beaviour during rolls, just dont do rollls! annoying because aileron tic tocs are much easier than regular ones

[bazsound]

well i got a bit excited with the tic tocs, got it really wrong and sent my heli into the ground. it was going down to fast to save it even with full positive collective, sounded like the head speed dropped ALOT i hit the ground bounced back up and i hit TH, did an arc going behind me.

Tried to float it down but you know how that alwasy goes with the 250, and bounced onto its side.

Broke the landing gear and tail fin. but no other aparrent damage. bit of CA and some CA soaked kitchen towel to reinforce.All good again

[bazsound]

have had the 250 out since the last crash. landing skids are holding up and it appears no other damage.

been doing half piroflips with ease. stills truggling on slower circles but i think thats the notchy rudder in slow circles.

[bazsound]

Managed to kill the esc and, BAR

Had my 450 out flying at a flooded quarry i fished. Well next time i brought the 250. Was a bit soft on the collective forgetting the 250 needs more collective faster to catch during a flip. Dunked it upto the bottom plate so esc and fbl soaked.

BAR freaked out givkng full rudder. Not wanting it to go further away i dint hit th waiting for it to come closer hit th and it dropped into the water in front of me.

Grabbed it out the water. Esc complaining about no throttle signal then smoke started coming from under canopy. Before i could get the battery unplugged the esc wires melted.

Damage. Blown fet on esc and BAR. - Correction BAR is fine


got a yep 18 as a replacent and a zyx-s if i cam get a sat to work with it

[bazsound]

Just got done fitting the YEP 18 ESC. Probably overkill but it was cheap and i already have a programming card for when i setup the YEP 40 for the 450. I like them nice options and governer too.

Ill need to get a bigger pinion to run the governer otherwise ill end up with too low headspeed so ill just run it as normal.

I decided to double check the BAR , plugged in rudder servo and it initilised and started reponding to movement, so plugged all other servos, same everything is working. took it for a test hover PERFECT>


I swear there was no response from anything when i powered it up with my 450's esc

[Krager]

Water messes with the connections on the circuit board by providing a high resistance current path. It typically will not cause a short hard enough to fry parts, but it will scramble signal lines.

Otherwise electronic components are encapsulated in an epoxy package so they're waterproof. Though the water will dry and leave a conductive residue on the board. You should give the Kbar board a brushing with rubbing alcohol and dry it with compressed air.

What happened with the ESC is if the switches are not opening and closing at the correct time it will cause a hard short. The water scrambled the control signals to the switches causing them to turn on at the wrong time.

[bazsound]

Originally Posted by CraigHB

Water messes with the connections on the circuit board by providing a high resistance current path. It typically will not cause a short hard enough to fry parts, but it will scramble signal lines.

Otherwise electronic components are encapsulated in an epoxy package so they're waterproof. Though the water will dry and leave a conductive residue on the board. You should give the Kbar board a brushing with rubbing alcohol and dry it with compressed air.

What happened with the ESC is if the switches are not opening and closing at the correct time it will cause a hard short. The water scrambled the control signals to the switches causing them to turn on at the wrong time.

Ill give the kbar a clean with IPA. got a 1 litre tin of the stuff.

The esc got damaged and then failed when i had everything dried out. it destroyed the batterry wires as it drew massive current. But was enough to damage the fets which let out the magic smoke when i put on new cabling. Not really lost anything i paid not very much for the whole electronics package that im surprised ive gotton such good use out of it. I paid something like £35 for the ESC motor and 4 servos (servos im not using they dont work well with kbar).

The YEP has already shown reliability issues. When i was setting it up it seemed to change settings itself on me. 1 time it counted 6 cells on initialisation, and when i put the programming card on sure enough it showed 6 cells.

It blips half way through spool up. It hovered fine but then when i took it to the local flying club it spooled up half way stopped, esc reinitilised and gave me the low voltage double beep.

I had to mess around with it for ages randomly changing options before i finally got it too work. 2 batteries no issues.

My YEP 40 on the 450 on the other hand was solid right from the get it, it complained once until i raised the start up power and been fine ever since

[Krager]

Originally Posted by bazsound

I paid something like £35 for the ESC motor and 4 servos (servos im not using they dont work well with kbar).

Man you got that stuff cheap, was that used? I'm building a new heli right now, Protos 380. I went with the less expensive parts, but still decent quality. It was like two fifty USD for that stuff, KST servos, Castle ESC, HK RotorStar motor.

People don't think much of those HK motors, but I've been using them and they're actually not that bad. A third the price of a an Xnova or Scorpion motor. I'm sure the inexpensive motors don't use the super high temperature rated magnets and coils like the high end motors, but if you don't overheat the motor in the first place you don't need it.

[bazsound]

Originally Posted by CraigHB

Man you got that stuff cheap, was that used? I'm building a new heli right now, Protos 380. I went with the less expensive parts, but still decent quality. It was like two fifty USD for that stuff, KST servos, Castle ESC, HK RotorStar motor.

People don't think much of those HK motors, but I've been using them and they're actually not that bad. A third the price of a an Xnova or Scorpion motor. I'm sure the inexpensive motors don't use the super high temperature rated magnets and coils like the high end motors, but if you don't overheat the motor in the first place you don't need it.

Yeah it really was too good to be true. it was from Eharibo website was "on sale" marked down from almost £100 you can guess why just wanting to get rid of stock. They didnt reply to emails wheen i complained about it being not fit for purpose.

i replaced the servos with a turnigy 306 on the tail and turnigy 213C on cyclic which work great although a little heavy.

the copterx servos worked ok when i was using the copterx 3x2000 gyro but when i moved to BAR it wobbled in the air and the tail took ages to get it to stop wagging and actually hold. The wobble never stopped until i changed it to the turnigy servos, i even tried a set of turnigy anologue metal gear servos but they also wobbled in the air.

[yakky]

Originally Posted by bazsound

I discovered that 1 of the wires in the sat reciever cable was held on by 1 strand. the cables that come with the lemonrx sats are horrible cheap cables. Ive ordered repalcements from hobbyking for both the 250 and 450. The much nicer ones with flexible cable instead of the hard black cable on the lemon rx ones.

Thge main problem with the lemon rx cable is that they are not crimped correctly, they are only crimped onto the bare wire so theres no strain relief.

They switched up cables early last year I think. They used to have nice 3 color cables but then switched to the stiff all black. IMO the Hobbyking Orange ones use wire that is excessively thick. Redcons seems to have a nice balance.

[Krager]

Those Turnigy servos are mostly rebrands. I knew which ones where which at one point, but I don't recall. There's some from a major servo maker and some from another small Chinese company. In any case, the rebrands are decent quality and they're inexpensive. I think it's kind of ridiculous to spend eighty some dollars on a micro-servo, ehem MKS ehem.

You need an unusually fast servo for the tail which limits options. They're not exactly a dime a dozen. I'm kind of on a "down with Spektrum" thing right now, currently moving all my radio stuff over to FrSky, but the Spektrum H3060 servo is a really fast micro-servo that's made for use as a tail servo. It's pretty well regarded in terms of performance and durability from what I've read.

I'm going to try a DS215MG V3 on the tail for my latest build, but it's probably not quite fast enough. If it doesn't work well I'll try that Spektrum servo. It may end up being the one and only piece of Spektrum hardware I still use.