walkera vs. align
 

just got turned on to electric helicopters and have narrowed it down to the dragonfly #36 or the 450 xl. the local hobby store carries t-rex parts but said that they can get the walkera parts. i am leaning towards the 450 xl but i can't find a complete kit (heli,electronics,batteris,charger ect.) for what i want to spend. even some of the transmitters take up more than my budget. does the dragonfly have as many upgradeable parts like the 450 (cf frames,cnc parts ect.)? can a good complete kit w/ EVERTHING in it be bought for a reasonable price? (i am wanting to do 3-d manuvers one day)

RE: walkera vs. align
 

Walkera electronics is total crap! Their transmitter is the worst piece of s&*#t I've ever seen!
Of course, you can make a decent or even great heli out of a Dragonfly, but only if you replace a bunch of parts and all its electronics. Don't be fooled by the low price of "ready to fly" Walkera package--you'll spend tons of money upgrading it. Just put Dragonfly and T-rex side by side and compare their quality. There will be no comparison. Then, take Walkera transmitter and compare it to, say, Hitec Optic 6. You'll see what I mean. Of course, T-Rex with a decent radio will cost a bit more, but avoiding the frustration of crappy Walkera is priceless!
:)

If that will be your first heli, consider reading this Electric Helicopter Beginner's Guide:
http://ehbg.rchomepage.com
(look for the file "ehbg-15-pdf.zip")

Boris

RE: walkera vs. align
 

thanks bluesky123 that reference will be a real time saver when i'm building one of those machines. i would still like to hear everyone else's opinion on the walkera and align helicopters. this stuff is awesome!!!

RE: walkera vs. align
 

He's right STAY AWAY FROM WALKERA!!! You'll be needing to replace everything as soon as you get it and regret buying it!!! The trex is the way to go!!!

RE: walkera vs. align
 

Hey ewr101,

Got an RTF T-Rex 450X as my first CP-heli from http://www.rc-expert.com/

For around 600 US Dollars, you get everything you need to fly, including the choice between 3 good computer-transmitters. I went for the Airtronics Sanwa RD8000, because I read good reviews about it and liked the idea of having 2 spare channels to connect future gadgets to. Seemed to give me the most bang for the buck feature-wise. It's a great radio and I haven't regretted my choice so far.

I got the "T-Rex 450X with carbon-parts", as described on: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5989129871 (in fact, this was that auction where I got it from :-).

The motor, servo's and flight-packs are all "RC Expert"-branded and I don't know the real manufacturers. The red 1800mAh 10C LiPo's are OK and give me 5-10 minutes of continuous hovering. Servo's seem to be OK as well. Precise motion, not too much slack, no chatter or slipping and quite fast. The carbon-coated "RC Expert" brushless motor that came with mine seems to deliver a good amount of power, but runs quite hot, even with the free heat-sink RC Expert sent me in an attempt to resolve the problem (although that helped quite a bit). I'm still investigating this problem, but mention it as something to check for with any new heli, as a burned motor can cause all kinds of nasty things to happen and excess heat-buildup in the motor seems to be quite common.

Read my reports in the "RC Expert"-thread on this forum for more info and tips.


Grtz,

Traveller

RE: walkera vs. align
 

the heating problem could be :gears too tight or your motor could be underpowered, if it's a too tight motor that's shortening your flight span.

RE: walkera vs. align
 

sweet set up traveler. the smart thing for me to do is save up more money and get one like that (angel on left shoulder) but i would like to just buy an el-cheapo helicopter to fly RIGHT NOW!! (devil on right shoulder) impatience is a very bad thing and i must resist. ha-ha

RE: walkera vs. align
 

Hey thecheatscalc,

Thanks for the tips. The gear-mesh between the motor and main-gear seems smooth, although I don't have a similar heli to compare the rest of the meshing to. Tail-belt seems to be at the proper tension, when checked the way the manual suggests it and there doesn't seem to be any binding in the swash. It is intresting that if I spool it up to around 50% power with 0 pitch, that even then the motor will eventually get very hot after 5-10 minutes of running (that was before the heat-sink was attached, so it could be significantly longer now). Could be an underpowered motor for the Rex, but it does feel like it provides plenty of power and even lifted the heli easily with my early home-made 175 gram training-gear attached to it. I'm going to try some pitch / throttle-curve adjustments and a lighter training-gear this evening. Maybe that helps a bit. If all else fails, I might try a different motor.


Grtz,

Traveller

RE: walkera vs. align
 

also what is the general opinion on the e-sky products??

RE: walkera vs. align
 

seem like it's ok.... you should be able to slip yet bend up a piece of paper when i goes through the gear mesh. Also i.v heard that the Trex usually takes a more powerful motor to lift it, it might just be something as simple as they miscalculated the best gear ratio and it just makes the lesser motors work a bit harder.
ok what pitch ae your blades at? if there too high that could be a problem, or, the moto is just going to run ot no matter what you do...:eek:
oh i forgot what size is the motor I'll bet it's a 380-400 brushed right?

RE: walkera vs. align
 

T-rex 450xl ccpm
over any walkera product

even though i got a walkera 36. mine has no problems except i need a new pinion

RE: walkera vs. align
 

the 36 was just the model i was looking at . what's the deal ?

RE: walkera vs. align
 

most 35 and 36 have power problems.
they just cant get the heli to fly cos the blades arent at enough rpm
some pople can get it to lift off for about 20 secs but thats about it

RE: walkera vs. align
 

Hey thecheatscalc,

The gears seem to pass the paper-test and when I turn the rotor, everything seems very smooth. When I'm on the ground after landing and cut throttle, it auto-rotates for 8 to 10 secs before coming to a stop, with 0 degrees pitch. Does that sound about right? The motor is 3200KV and (from counting) has a 12T or 13T pinion on it. I don't know it's exact specs but it is brushless and seems to provide plenty of power. There's not much specs about it on RC Expert's site.

From just listening to it, the head-speed around half stick (where it hovers comfortably) seems about right and the same as other T-Rexes I've listened to in several movies I got off the web. I don't have a tachometer, so I can't give you exact figures. I don't have a pitch-gauge either and adjusted the 0-degree point by spooling it up a bit and adjusting the pitch center-point to where there's as little wind from either side of the rotor as possible. This is also very close to the mechanical center-point, as shown in the manual. Made that 50% of pitch servo-travel in my TX and used the throttle and pitch-curves from http://www.trextuning.com/setuptrex.htm

As I said, that brings it into a nice hover, 0.5 to 1 meter off the ground around half stick. I emptied all of my 4 flight-packs this evening and must have had it in the air for at least 40 minutes total. Tried to give it a bit more head-speed and decrease the pitch a little, but that didn't help much. With the heat-sink on, it gets too hot to touch and starts to emit that familiar smell you get from overheating transformers after just 4 minutes of hovering. It also worries me that the motor gets very hot reasonably fast when spooling up at 0 degree pitch and leaving it running at 50% power for a few minutes. Do you have any experience with the Align BL-420LF 3200KV brushless on a T-Rex 450X? Does it have enough power and which pinion would be best to use? I'm planning on giving that one a try. If you have any other tips after reading the above, let me know. Thanks!


Grtz,

Traveller

RE: walkera vs. align
 

well it seems that every thing is in order (minus the hot elec. smell) I don't know what to say the heli is lifting off at the right amount of throttle and everything... try making it hover at 3/4 throttle that might help a bit and release a bit of strain.

just a wild (and random) guess is that the tail rotor belt could be tight and causing a bit of problems i don't know this does seem strange though. also how hot are the batteries getting?

RE: walkera vs. align
 

Hey thecheatscalc,

I'll try adjusting the pitch to get it hovering around 3/4 stick next time. As I mentioned earlier, the belt-tension seems to be OK, when tested as the manual describes. Again, I don't have anything to compare it to, but it feels right. Doesn't require much pressure to almost make the insides touch near the gear. I read somewhere on these forums that the belt should be so loose that it slips if you hold the main rotor and turn the tail-rotor with little force. Mine doesn't seem to slip very easily, but I don't dare to put too much force on it. Besides, the belt and the gears it runs between seem to have a mesh as well, which seems to be there to actually prevent slipping. Maybe they were talking about a different heli, but I seem to remember that it was the Rex.

The batteries get little more than hand-warm during most of the flight, but their generated heat rises sharply to around 40 or 50 degrees C at the very end of their discharge. AFAIK, this is normal for LiPo's. I've set my (soft) LVC to around 3V per cell under load. Unfortunately, I don't have the correct cable to measure current-draw at the moment. Calculated from the approximate flight-time I get from my 1800mAh LiPo's (around 10 minutes), I estimate the average current-draw to be around 10A.

Anyways, thanks for your help. I'll probably try a different motor if I can't find another fix.


Grtz,

Traveller

RE: walkera vs. align
 

:) I wouldn't really call it free as you kinda paid $ 600,- for the kit in the first place, they should have included it from the start. With the volume it seems like they are turning out they should know you'll need it and what other components that work or not. I for one has told them some...;)

RE: walkera vs. align
 

Hey Norrmannen,

True, if the problem is known, they should try to fix it in the future similar sets they sell. They do seem to try as best as possible to get my 2 problems I still have (motor-temperature and the ESC that doesn't have governor-mode as advertized) resolved and will probably send replacements for those to test with as well. I'm trying to get an Align BL-420LF motor and the Align BL-25G ESC. If that combo turns out to work well, I'll certainly suggest they use that in the future, as the difference in price is minimal. The Align-motor also seems specifically designed for the Rex and comes with full specs.


Grtz,

Traveller

RE: walkera vs. align
 

oh , traveler, I just thought that the blades might be a bit too large (long) for your motor. That WOULD make the motor strain and cause problems, so, making it lift off at 3/4 throttle would help, OR you could clip the wings a few millimeters. (please don't ask me how, I really don't know [:o]) if you have some shorter blades you could put those on and test that theory in any case I'd like to know the results of that

RE: walkera vs. align
 

Hey thecheatscalc,

As I'm still learning and realize that this increases the chances of a crash and wrecking the blades, I haven't flown with anything but the stock ABS blades yet. I think they are 310mm or so, which is the shortest of what came with the set. I don't think I would want to try and clip them at this point. Could try one of the sets of 315mm woodies that came with it, to see if it makes a difference. I also have a set of CF main blades. Could those help, because of their reduced weight? Maybe I'm going for some more flying later this evening, so I'll let you know how it went.


Grtz,

Traveller

RE: walkera vs. align
 

Hey thecheatscalc,

Ok, tried the woodies. If anything, they made the problem worse, but I didn't notice that much of a difference, even in lift. Only the trim changed somewhat, so it was all over the place for the first few minutes. Still not a single crash since I have it *crosses fingers and knocks on wood, for good measure* Only doing simple tail-in hovering and a bit of moving yet, though.


Grtz,

Traveller

RE: walkera vs. align
 

It may be worth noting, that most brushless motors, regardless of setup, will run warm to hot during use. If you can't keep your finger on the motor for more than 2 seconds, it's too hot. If you've got a heatsink, don't touch the heatsink to guage motor temperature, touch the motor it's self if possible. The purpose of the heatsink is to draw the heat away from the motor can. If the heatsink is hot, it's doing it's job. The motor it's self should only be warm to moderately hot. If your ESC and batteries are getting hot along with your motor, then you're pulling to much power. If it's just your motor that's running hot, it probably just naturally runs hot. More efficent motors will run cooler than less efficent (cheaper) motors will. Some brushless motors even have built in cooling fans and/or fins to aid in combating heat. At any rate, most setups will run hot after prolonged flight. Unless the motor is scorchingly hot, I wouldn't worry to much about it.

RE: walkera vs. align
 

Hey credence,

The heat-sink indeed runs hotter than the motor itself. I also used some heat-conducting paste when clamping it on, so it's really as efficient as possible. After 3-4 minutes of flight, the underside of the motor is too hot to touch for even a second. The motor also starts to emit an alarming aroma of overheating windings and plastic. No smoke, but that's probably just because I usually give it about 5 minutes to cool off for every 2 minutes of flight.

The ESC runs moderately hot, but I can still keep my finger on it's heat-sink. The batteries run little more than warm to the touch for most of the flight, but quicly pick up temperature at the end of their discharge-cycle and are usually 40-50 degrees C at the end of the flight, when the LVC kicks in at 3V per cell. I haven't measured exact temperatures yet.

BTW: The Align BL-420LF I'm intrested in as a replacement has a built-in cooling-fan. The heat-sink from my current motor should also fit it, for even more extra cooling.


Grtz,

Traveller

RE: walkera vs. align
 

Well, if you're starting to smell the wonderful aroma of burned plastic and fried electronics, I think it's time to look into a new motor :)

Granted, brushless motors can get pretty hot before they become physically damaged. But if you're running that hot to begin with, well, it's just not good for your setup, and the LAST thing you want, is for the motor to die while you're in mid-flight. Better to be safe than sorry. Align motors are supposed to be pretty good for what you get, from what I hear. Let us know how it goes :)

RE: walkera vs. align
 

Hey credence,

I hope to be getting my replacement motor (Align 420LF, 3200KV) and ESC somewhere next week. I also asked for several pinions (11T, 13T and 15T), in case 13T proves to be a less than ideal match. I'll let you know how it goes. For now, I'll keep flying carefully, allowing the motor plenty of time to cool down in between, hoping that I won't get an accellerated crash-course in auto-rotations. ;-)


Grtz,

Traveller