Walkera V Clone Projects (T-rex, ect.) - Page 2 - RC Groups
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Jul 23, 2011, 05:36 PM
Human Being
hey kdean, thanks for the info, i didn't get a manual because I ordered it from ebay and it came wrapped in chinese newspaper.

Turns out though the servo problem is my own fault... you mentioned digital servo, which I thought I had bought, but turns out I bought the ES08MA instead of the ES08MD. The A for analog and D for digital The servos on my 400 however are digital, so maybe i'll steal those for a while since the frame is cracked and awaiting repair. Tho, since those are all hacked up to fit that heli with holes drilled special for it, I don't really want to do that, but the temptation might get to me.
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Jul 23, 2011, 08:07 PM
Human Being
Alright, i replaced my servos with the ones from the v400

haven't had a chance yet to try to set it up like you mentioned, just finished modifying them and installing them. I'm getting ready to go out now, so probably won't finish until tomorrow. If I can do my bench testing and setup of the servos and controllers tomorrow, maybe by the afternoon i'll have her in the air

You weren't kidding about those screw heads wanting to strip really easy. especially the tiny hex bolts, who thought that super tiny hex bolts be a good idea anyway... just asking for trouble.

How's your v500 project coming along?
Jul 24, 2011, 03:03 AM
kdean's Avatar
Everything is on hold right now. Waiting for parts.
Jul 24, 2011, 04:37 PM
Human Being
finally got the v450 put together, set my swash and pitch, programmed the esc, went through the servo setup (per your steps, thanks), checked that the gyros appeared to be in the right direction (they were, but moved more slowly than i recall), ran it all without the blades, set my rx potentiometers based on a vid i saw on youtube, then took it out back for one more check over and a test flight.

Well things didn't go so great....
I would throttle up, and right about the time it was ready to lift off, it kept wanting to tip left or right real bad (mostly left i think). I'd try to straighten it out but it wouldn't stay. I was messing around with the knobs on the rx and trying again (I thoroughly confused myself as to which way would make more sense to turn it up or down, the + and - are around a circle, so it could be either way). I tried about every combo I could think of, but it didn't seem to help much. At one point i had it about two inches off the ground before it took a dive. I think that one busted the shaft inside the tail (maybe belt driven would be better..) cause all the gears up to the shaft move fine, and it looks ok, but there is no power transmission through the tail boom anymore. I'll take that apart and see if I can fix it, then i'm just back to my original problem.

Not too sure if I just haven't found the right settings for the rx/tx, or something is wrong with the gyro in the rx. Hopefully it's just my settings, I haven't had a chance yet to reverse the Aile switch on the rx, it's possible this is the issue. When i tilt the helicopter though, it looks like the swash plate goes to the correct direction, though they only move very slowly and very little. Anyway, i'll try to take apart the tail and hopefully fix it, then try reversing some of the gyros. Did you have to reverse any of yours, kdean? I think I have mine located in the same place as you do. I have my rx mounted where the gyro would typically go, it's behind the main shaft with the antenna pointing toward the tail and wires pointing toward the main shaft
Jul 24, 2011, 06:33 PM
Human Being
still working on it.... I fixed the tail, it had just pulled out too far and disengaged, and then reversed the aile switch on the rx. I thought it was feeling a little more stable when just scooting, so I went to see if i could hover when she took a quick dive left and snapped off both the blades and sent them wizzing past me The flybar also got all bent up. I have spare blades, and maybe i can straighten the flybar and try again....
Jul 24, 2011, 07:17 PM
kdean's Avatar
Thats sounds like the problem i had with the 4f200 rx. I still cant figure out why the gyro / servos cant do what i want it to do. On my 2702v rx i have the alie and elev switches in the off position, so none of them are reversed. In my tx i had to reverse the elev and pitch servos, but thats using the stock v450 servos. Your servo type might make your set-up different. Also, i turned the sesnitivity and balance delay all the way down because of the flybar. I did try adding the 3 axis gyro while testing it the last time, and like you the alieron gyro hardly moves and its hard to tell if its going in the right direction. The elev gyro is not a problem. I can see and feel it working, but i dont know what the alieron gyro is doing...

I wont get a chance to fly it today, i really want to check the pitch changes i had to make. Hopefully tomorrow.

Take it slow. Good luck.
Jul 24, 2011, 08:22 PM
Human Being
wooohoooo! well, kinda, but...

the good news is that i finally got it to hover for about 10 seconds, the bad news is that it wobbles like a s.o.b. Think i bent the main shaft during one of my collisions trying to get it set up right. since it's trex parts though i can go to the hobby shop tomorrow

thanks for all your help kdean, and maybe my troubles here can shed some light on your 4f200. In the end it all had to do with the on off switches on the rx. Even though the gyros kinda looked like they were working correctly, they weren't, it was just my mind playing tricks on me. You know how i said they were kind of slow (more so the aileron than the elevator), well it could be because the movement i was paying attention to was the "return trip" of the servos instead of the correction.

It sounds like your 2702 is opposite from mine. On the rx I had to reverse both the aileron and elevator servos, and on the tx I had to reverse the aileron.

Having to reverse the elevator gyro really threw me off, because when I had both of them in the off position the elevator gyro seemed to be working better and quicker than the aileron gyro and i was pretty sure that one was in the right direction. Maybe having both of the gyros in the off position when they both had to be on is what made me think they were working. On your 4f200, it might be worth a shot to switch both the elevator and aileron gyros at the same time and see what you get... even without flying you might notice a big difference in the gyro swash correction, once mine was working right i could definitely tell.
Jul 24, 2011, 09:03 PM
Human Being


I just want to post some useful youtube videos I came across.

The first one is from somebody with a 450 clone (though not pro) with the walkera 2702v rx. He also still has the flybar on it, and demos a flight, so you know it works. He talked about the knobs on the rx, which I followed his settings with and got mine to hover (i had to look close at his to tell which way all the way up and all the way down is). However he does not talk about the switches for the gyro reverse (the tiny on/off switches on the rx). On mine I had to turn Aile R and Elev R on, but kdean did not, so you may have to mess with these. Here is that vid, about 2 to 3 minutes into it he spends a minute or two talking about the rx.

Walkera 2801 Pro/Rx2702v setup for Trex 450/clone helicopters, plus test flight. (16 min 24 sec)

Another video that is helpful is about setting swashplate and pitch with a flybarred heli. I had to revisit this, because this is my first heli with a flybar.

CopterX 450 pitch & blade tracking W1008 (1 min 40 sec)

The last video shows the ccpm servo arm setup, similar to what kdean wrote a few posts back. Reading kdeans post specific to the 2702, and watching this general video should get you there.

Crash Course in 120 CCPM Setup (9 min 2 sec)

Hope that helps anybody else with a similar project that comes across this thread. If you do have a similar project going on and find this at least somewhat useful, feel free to post and say hi
Jul 25, 2011, 10:28 PM
kdean's Avatar
Here are some pics of my 450 por projects. I just had the one in the front out for some 17 tests. I think things are good, i added some gyro sens to both alie and elev and did not get any wobble. There is a pic of the rx settings. Im still not sure if the alieron gyro is working. I tilt the heli and the swash does not move. It did feel a little tippy, and it does correct yaw eventualy, but needs constant alieron inputs to stay level. When i get my new 2702v i'll check to see if it is normal for the alieron gyro to act like its not working. I may just be the flybar that is saveing the heli from tipping without corection.

I did adjust my swash mix in the tx to make it more agile. It is recomended that all swash mix be set at 70%, but i found that it made loops difficult due to not enough elev extent. So, i now have elev at 80%, alie at 70%, and pitch at 80%. I was able to do much tighter loops today. Still not perfect at it, i seem to be leaning on the alieron a bit when i pull back on the elevator. The tail is very locked in. The breeze was blowing my v400 tail around, but the v450 held nice. Piros are fast and stop on a dime, very crisp. (as tony from xheli would say)
Jul 25, 2011, 10:56 PM
Human Being
Glad to hear you're having a good heli day! I finally got my 450 into a decent hover and flew around a bit, so i finally had a maiden flight

After replacing my main shaft and flybar shaft (still need a feathering shaft cause the blades aren't tracking great, but forgot to pick that up), I had the wobble almost totally gone. I was flying around, then the wobble all of the sudden came back with a vengeance. I had been meaning to secure my rx better because I had only taped it on with double sided tape, barely hanging onto the location for the 450 gyro. When flying the wobble kept increasing so I had to land in the tall grass and my tail rotor chopped at the grass. This stripped my tail drive shaft gears (the little differential type angle gears near the main gear). I zip tied my rx on and it's much more secure now, and it seemed more stable in the air, but when I took off I had tail wag issues due to the stripped gears, so I've had to ground it for a bit until I can get some new gears. Looks like another trip to the hobby shop tomorrow I think though once I get that worked out (and a new feathering shaft), it'll be flying nice. That one flight around the backyard really got me feeling good about this heli

That pic of your rx setup is pretty handy. Are the servo sensitivities turned mostly up there? Mine are probably 80% up right now, but i haven't had a chance to play around with them much yet. I have tail delay and balance delay all the way down.
Jul 26, 2011, 04:29 AM
kdean's Avatar

2612v rx

After some youtube research, i found the this rx (from 4f200) can be used on t-rex type helis. Due to the difference in servo placement, the rx needs to be mounted upside down. Common placement is under the heli, or on the 250 size under the rx mounting plate.

I did see one vid with the rx right side up but he did not share his rx/tx settings.

So, i'll continue to play with the idea, and try to find a nice place to mount my upsidedown rx.
Jul 26, 2011, 09:07 AM
Human Being
Originally Posted by kdean
After some youtube research, i found the this rx (from 4f200) can be used on t-rex type helis. Due to the difference in servo placement, the rx needs to be mounted upside down. Common placement is under the heli, or on the 250 size under the rx mounting plate.

I did see one vid with the rx right side up but he did not share his rx/tx settings.

So, i'll continue to play with the idea, and try to find a nice place to mount my upsidedown rx.
good deal, as long as you know that it works on this type of heli then that sheds some hope on it again. Uspide down is kinda strange though... Walkera does seem to like to put their elevator servos in the front though, so things could be all mixed and matched. Plus based on that your 2702 receiver is mounted the same way as mine, but you didn't have to reverse your gyros, then it's probably that different servos can cause all types of different combos. I just hope you can get through the trial phase of testing the rx without bending parts of the heli like I did
Jul 26, 2011, 08:41 PM
kdean's Avatar

Servo Warning

Hey guys,

Once again walkera servos cause me grief and leave me on the bench with repairs.

I had my V450 out yesterday, and got 4 flights without a hitch. Took it out againg today and the first flight was perfect. The second flight started out fine, was able to get some loops in, and ran some ff circuts, i even did a roll. Then, while doing a circut about 40 feet up, comeing out of a left turn, the heli suddenly tilted to the left. I was able to correct but it then tilted forward and i lost all elevator control. So she went down face first into ground. As i picked up the pieces, i could smell the familar white smoke that came out of one of my other wk 09 09 servos while testing on the bench. And yes, it was the elevator servo that burnt.

Damage includes, blade grip, horizontal shaft, canopy, tail boom, and a new servo. I dont think i'll be flying with walkera servos anymore. When my heli budget allows, i'll be outfitting my helis with hitec servos.
Jul 26, 2011, 10:55 PM
Human Being
that's too bad about the servo issue, and unfortunately when one part goes bad, many end up needing to be replaced I might look into upgrading my servos to the hitec before they go out on me (tryin to learn from your mistakes, as i hope people learn from mine...)

for me though, i've had a great heli day I had a rock solid hover in my garage tonight with the v450pro Once i replaced the main shaft and the feathering shaft after my severe blade strike when setting up, I started again to hover and it did ummm ok. It still seemed to want to wobble, and i noticed when it started wobbling it amplified itself to an uncontrollable mess, so i needed to land quickly (good reflexes combo'ed with reeeaaaalllly not wanting to crash my heli again did me well tonight). Since I knew everything should be straight enough with new parts (and i could see blade tracking was excellent), i started messing with the gyro settings. I tried little by little, but in the end, turning the gyro potentiometers (little screw looking things) on the rx all the way down ended up being the best. I tried with tail d. and bal d. up half way but couldn't tell much of a difference so i turned them back down. When everything was turned down, and I had the rx ziptied in real tight, she seemed to hover wonderfully can't wait to take her out to the park in daylight

fyi for anybody with this rx, the + and - sign may not be that intuitive. I found that Negative ( - )is CounterClockWise, and Positive ( + ) is Clockwise. Another way of saying that is if you line up the flathead screw slot so that it sits right between the + and - , then you would want to look where the + and - are real close to each other, and that's the direction you need to turn the knob.
Jul 27, 2011, 03:56 AM
kdean's Avatar
After some parts swaping, i now have a flyable v450 pro. Its really a mix of t-rex parts from 4 different places. Its got some EXI, some Tarot, some Alzrc, and some Align.

The alzrc flybarless head has one exi blade grip (grey), and one tarot grip (black). I just have to reset the swash links for the fbl head, and set up the servos with the 2702v rx. Im a little sceptical about this gyro system. Espicialy after the quick nose over this heli did when i was testing the fbl head with the 2612v rx. I still dont like that i cant see the aileron gyro working. I can see the corection tilt on my v400s', and i'm now wondering if it is faulty or not. I will need to have success with this flybarless set-up in a 450 before i try it in a 500.

I'll run alot of bench tests tomorrow before i even think of putting blades on it.

That reminds me, i need to order more blades. My V400s' never crashed this much, but i never flew them as hard.....

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