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Old Jul 18, 2011, 03:07 AM
BahamaHeli
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Walkera V Clone Projects (T-rex, ect.)

This thread is inspired by the stable flight of the walkera 3 axis gyro / recievers.

My first cp heli was the Walkera V400D02, and I'm so impressed with the flight characteristics and ease of use of the flybarless rx, I decided to use one in a T-rex Pro clone project. I was not impressed with the quality and durabilty of the walkera frames and other componants that come with their kits. And the V450 is just plain ugly. So, my first project heli was an EXI 450 pro (tt), with a Hobbywing Platnium 40a esc, Turbo Ace 804 (3950kv) motor, and the servos and flybarless reciever from the walkera V450.

My maiden flight of that heli ended in a crash due to not haveing put thread lock on the center bolt of the pitch slider. It now has the updated wk 09-09 cyclic servos, and the walkera tail servo did last for 20 flights before it just stopped working completely. With my experience with the V400, I can safely say that walkera does not make good servos.

Once I had that project flying I was able to pick up another 450 pro frame, this one by Tarot, and started another clone project. I had a smaller budget on this one so I went with the rx from the walkera 4f200, Exceed Alpha 400 (3500kv) motor and 40A esc, Blue Arrow digital mg cyclic servos, and high speed tail servo. This servo is now in the EXI frame along with a Alzrc flybarless head and other upgrades such as, cf tail boom, and aluminium battery mount. I've also been replaceing certain parts for genuine align like main gears and tail gears.

I've been running into my share of problems along the way, and that is why I started this thread. To share my problems with you, who may already have a hybrid heli, or are thinking about getting started on your own similar project.

Lets talk about it...

I also have an hk500 cmt (tt) on the way, and plan on converting that to a walkera flybarless (V) as well.
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Old Jul 18, 2011, 09:01 AM
Human Being
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I also have a walkera/trex clone project that I will begin as soon as my parts start showing up. I have a V400 and a little cb100, and now i'm looking forward to getting this project heli up and running. I plan to start with the flybar, and then maybe after a few weeks of flying, when i'm ready for a change, i'll try to mod it to take the flybar off. The good thing about the walkera rx is that it has all the flybarless gyros built in, and I think kdean had it figured out that to modify it to flybarless is only about 40 bucks.

Here is my part list that is on the way for anybody interested:


Kit: EXI 450 pro shaft driven tail, xheli $70 + 11shipping
http://www.xheli.com/18h20-exi450pro-shaft.html

Motor: Alpha 400 3500kv brushless motor, xheli $13 + 2 shipping (bought with kit)
http://www.xheli.com/al4003oubrmo.html

Transmitter: walkera 2801, hobby-wing $145 + 30 shipping
http://www.hobby-wing.com/walkera-wk...radio-set.html

Servos: (EDIT: don't get these the cyclic ones don't work, you need the digital servos ES08MD, with the D being the key letter there) EMAX ES08MA ES020 Servos Combo, hobby-wing $35 + 2 shipping (bought with transmitter)
http://www.hobby-wing.com/emax-es08m...vos-combo.html

Receiver: walkera RX2702V (typically comes on the v450), ebay, $99 + 5 shipping
http://cgi.ebay.com/ws/eBayISAPI.dll...m=250848715924

ESC: exceed 40A brushless esc with BEC, (volcano series), hobbypartz $21 + 5 shipping
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Last edited by dilberto; Jul 23, 2011 at 07:30 PM. Reason: wrong servos
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Old Jul 18, 2011, 01:53 PM
BahamaHeli
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This is the link to the blog i started on the Helifreak fourm.

www.helifreak.com/blog.php?b=1629

It also has alot of videos and info on the 450 pro build process.
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Old Jul 18, 2011, 03:31 PM
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I'll have to register with helifreak i guess, because it won't let me view unless I do. no biggie, i'll do that later.

Meanwhile, i placed an order from 3 gen ace batteries for 16 bucks a pop (& free shipping)
http://www.hobbypartz.com/98p-25c-2200-3s1p.html

and the first of my 450 shipments should have come in the mail today, the 2801 tx, so i'm going to go home and mess around with it on my v400.
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Old Jul 20, 2011, 12:16 PM
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Got all my parts in except the receiver. That one still doesn't show a tracking number and says estimated delivery June 28th - Aug 10th Maybe i should have spent the extra 20 bucks and gotten it from somewhere else... Ah well, it'll give me plenty of time to build the rest of it right (loctite every screw, etc..)
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Old Jul 20, 2011, 09:30 PM
BahamaHeli
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So, after makeing some changes between my two 450's, I got the flybarless head on the V450 pro (with 2702v rx) and took it out for is maiden 'flybarless' flight. Did some fooling around with the rx cause i had turned all the gains and sesitivities down because i was using it with the stock exi flybar head. I think i for to change something cause it just did not want to liftoff, kind of like the F450 did when i was trying to get it in the air. In my desperation i just went for it. I was already up to 70% throttle/pitch, so i pushed a bit more. Whats the worst that could happen? Well, the worst did happen. It went up a bit then forward, right on to the blades. It happened so fast i could only pull down the throttle and look in amazment. I have a feeling something is reversed in the rx/gyro. I need to go watch that youtube vid again, i'll post it when i find it. The damage is onlt the main gear, cracked the cf tail boom, bent the tail blabe shaft, and stripped a main blade ball joint out. Im pleased with the walkera 09 09 servos for holding up. I was expecting at least two of them to strip. I have the spare parts, except for the blade grips.

I did realize the 4f200 rx is backwards on my F450, and i need to mount it the other way for the gyro to respond properly. I'll test that one tomorrow.

My hk500 is here. Now i can go ahead and order the 2702v to put in it. Along with some other things i want to swao out right away. For some reason i thought i orderd the tt version but i got the belt version. When/if you order from hobbyking double check before checkout. It does'nt matter, im ordering a complete align tt tail section anyway. The hk tail are prone to throwing a blade every now and then.

That right dilberto, loc tite everything you can get off. Some screws and bolts wont budge, if you dont have to move it, dont. You will end up stripping heads and getting frustrated. Have fun.
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Old Jul 21, 2011, 01:17 AM
BahamaHeli
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Just spent the last few hours trying to get the 4f200 rx to work with the 450 pro with no success. I tried reversing it, using different swash settings, but it wont do what i want it to. Either the elev gyro is swinging the wrong way or the alieron gyro swings the wrong way. When i try different servo hookup combinations, the swash does some funky things with alieron controls. I give up. I'll use it in my V400 brushless tail conversion to bypass the stock esc and signal convertors.

So, i'll be ordering another 2702v for the 500, and get a quark and the 2801 rx and leave one of the 450s' as a flybar.

If anyone has any idea on how to make the 4f200 rx to work with the 450 pro servo layout, let me know.
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Old Jul 21, 2011, 02:17 AM
BahamaHeli
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I spoke to soon. Doing some bench testing on the V450 pro, to make sure the gyro was responding in the right directions, and the magic puff of smoke came out of the alieron servo. Its burnt, and I just said how suprised i was that all the walkera servos survived the crash. I guess its a delayed response. One more thing on my next order list.
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Old Jul 21, 2011, 10:14 AM
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too bad you're having all those problems. part of the hobby i guess. frustrating, but i'm sure you're learning a helluva lot

I have most of my parts for my 450 project, still waiting on the 2702 rx, but I finally got a tracking number, so it's on it's way

I haven't yet began to put together the v450pro yet. I was sick the last two days, and once sat down to try to work on it, but ended up staring at it for about an hour and picking up parts, staring at them, and setting them back down cause I couldn't think straight. I'm feeling better now though, so this evening I might start on it.

A couple of things I wasn't sure about so was looking up: it looks like the servo arm length for the cyclic (swash plate) servos should be at 15mm, and the tail at 10mm. The other thing, it looks like some people took apart their frame to put the servos inside it, and bolted the one side servo onto the inside of the frame. I plan to just take off the front plastic piece of the frame to install the 2 servos that are next to each other. And for the servo that is on the side of the frame, I was just going to bolt that from the outside, instead of trying to bolt it from the inside. I don't think it'll make much of a difference for flight, and from pics on the internet, i've seen it done both ways. If you know what i'm talking about kdean, which way did you bolt on that servo (the way it's easy to get out, or the way you would have to take the frame apart a little to replace it)?

anyway, that's all my observations for now, i'll post more little quirks and questions and whatnot when i start to build.

Meanwhile, I noticed on my v400d02 that my frame is cracked and split, and the wobble has become too bad to fly. Looks like i've got some repairs to do on that one too, so right now i'm once again birdless
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Old Jul 21, 2011, 03:57 PM
BahamaHeli
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The only problem you might have, it depends on the shape of your servo, the elevator servo arm might end up centered with the swash link. That would put the link between the servo and the swash at an angle. But like i said all servos are not the same dimentions at the top so it might work out for you. I tried to keep my links as straight line as possible. Though it would be alot easier to have the elev servo mounted on the outside.
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Old Jul 21, 2011, 08:40 PM
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It looks like this servo will be ok mounted from the outside, once i put the ball link on there it should be close enough. I think i'll have to reverse at least the elevator servo, either that or the aileron and pitch servos. I've been working on this some tonight, mounted my motor and ESC and have been setting up the servos. I don't have my rx yet, so i'm using the v400s. Looking at pics of the v450 it looks like its set up a bit different so it's hard to tell, but the servos definitely won't swing the swash plate the right way with the v400 rx the way i have it set up. It should be alright though cause it looks like I can reverse them on the tx if i need to.

It's been coming along though, i've been singing darn christmas songs in my head while i work on it (here comes santa clause), cause i feel like an elf making myself a new toy

think i'm done for the evening though, going to go watch Dexter (good show by the way, just got into it).
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Old Jul 23, 2011, 05:41 AM
BahamaHeli
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Started the 500, still waiting for my stuff from wow...

My wife has me watching all kinds of shows on tv. Things i would never watch if she did'nt turn to that channel religiously on certain days of the week.
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Old Jul 23, 2011, 01:51 PM
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I've been working on my v450 pro, and i'm getting very close to finished, but something's not quite right my cyclic servos aren't working correctly.

I got my rx in the mail and plugged everything in. First it seemed that the servos were working, when i moved the joystick on the tx, they would move. I changed some of the servo settings, making sure i had 3 servo 120 degrees set, etc. After a few times of messing with things and changing things, I no longer get any response from the servos when i move the tx joystick. I thought maybe i messed up too many settings, so I went back to the v400 settings (what I started with for the v450), and still no luck. It's strange, because when I first power it up, one of the servos throws the arm high and holds it there. The other two don't seem to do anything, which they were before. The tail servo seems to be working ok. I wonder if i got bad servos or if my rx is bad..... maybe i'll make a trip to the hobby shop and pay a ton for some new servos to see if they work.

On the 2702 rx there are 4 switches, do you have them all on?

Guess i'll start swapping things with the v400 to see if i can pinpoint the problem.
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Old Jul 23, 2011, 02:05 PM
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plugged the 450's servos into the 400's rx, and they did the same weird thing. Then I plugged the 400's servos into the 450 rx, and they seemed to work fine. I think i just got some bad servos, or ones that don't work with this rx. hmm, was hoping to get flying this weekend, but if i'm going to do that i'd need to make a trip to the hobby store. not sure if i'll do that or just order some new ones online.
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Old Jul 23, 2011, 03:20 PM
BahamaHeli
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Hey dil,

you have to set your swash travel on the rx. If you went into the set up and did not do it right the servos will not travel. The reason the other servos work is because they are anolog and will not respond to the digital commands frim the rx. Did you a manual with your rx? Its a pretty simple process. I'll try to quickly get you through the steps.

Put all your switches on the rx to the off, or top, position. The switch that says 'tail set/sw set', flip that to sw set, (swash setup).

Bind the tx, unplug motor, turn up you throttle/pitch to 50%. Make sure your mechanical set up is good, (level swash, centered swash, washout arms level, 0 pitch on blades). Check your swash movement, if you have to reverse servos do it now. Check gyro directions, the swash should move opposite direction when you tilt the heli. If you have to reverse the gyro direction for either elev, or alie, use the switch on the rx.

Enter set up mode by pressing and holding the set button.

When all the mechanical stuff is good, press the set button a second time to enter ccpm travel setup. The green light for elev will flash. Push the elev stick all the way up and hold until the servos stop, then press set button.

The alie light will now light up. Push the alie stick to the right and hold, press the set button when the servos stop.

It will do a little dance, and thats it.

You may need to go straight to elev and alie travel set firts, just to get you servos moveing again.

Dont throw your servos away, good luck.

There is a similar process for the tail.
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Last edited by kdean; Jul 23, 2011 at 03:29 PM.
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