Trex 250 Build Log

[Doozer]

USPS has this heli right now.

Feb. 02 - Happy Ground Hog Day!!! Tracking says it arrived in Phoenix this morning... that's a good sign I generally get it the same day when that happens.

I've been busy mulling over build threads and build videos. I will be choosing the builds and videos that I think are most helpful to me and linking them in this thread.

This is my first time building a Trex. I can tear the Walkera 4#3 down blindfolded, so dealing with sub micro parts is no big deal to me. In a lot of the videos you see, they complain about the size of the parts. I laugh at that. Stab yourself in the hand with a phillips head screwdriver trying to get the screw in a 4#3 blade grip, then talk to me.

Speaking of Walkera 4#3's, I plan on doing a brushless set up thread as soon as people start selling the parts. They are selling the brushless helis, but I have 3 x HM4#3B's that I would rather convert to brushless. But this is another thread.

That's it for now, I'm just killing time until it gets here.

[Doozer]

It's here and I just wanted to say wow! Very impressed with the quality of the packaging alone. Circus packaging for sure. This is a newer version, because from the what's in the box videos I've seen, there is no parts tray, and I was definitely packed differently. So here's some pics:


Here's the box next to my 6" calipers


The box fits in the length of the boom of my Neon (300 class)


I purchase a ton of extra parts. Here they are in front of the unopened box. Extra main shafts; feathering shafts, tail shafts; ball links, flybars, dogbones, main blades, tail blades, frame screws; belt, and a blade holder... which I didn't need.


No battery comes with the kit. This is the one I bought


It comes with an adapter for the charging harness


I wish they'd come pack my car for trips


Parts Tray


Servos; Head; Shaft; The head comes just about complete. All you need to do is put the flybar cage on.


Comes with extra blades.... I didn't read that! very cool


Gyro; Speed Controller; Tail Servo; Glued to the top of the box.


Comes with a useable manual. Imagine that.


The frame and motor; Screwdrivers; Tail; Boom up top


Closer view.


They pack a lot of stuff in this little box.


There it is


Nice skids


Even comes with locktite. I kind of have mixed feelings on this. I'm glad the provided it, but as you can see, they didn't put much in there. For as much money as you pay for this kit. They could give you more. This says to me "you've got enough for your money."

Anyway, I'm going to start on the head as soon as I watch another video. I'll post more pics later.

[Doozer]

I'm about 3/4 of the way done and I just wanted to throw up a quick update w/o any pictures. I've got to work over the next four days so my time is limited. I can post some from work between groups or on my lunch.

Anyway, First impression... very nice heli. The manual is actually a manual. Every detail imaginable is covered, right down to how long your links should be, and the gap size for meshing. It's not Step 1 do this, Step 2 do that kind of lead you down the path type instructions so if you haven't done one of these before you might be a little lost. Everything is in exploded view, and it tells you where to locktite and what screws to use.

The one complaint is that I'm not sure how they went about organizing what to put in each bag. If you follow the manual, you find yourself dipping in one bag here and another bag there. I don't open my bags until I'm ready to use them so their bag strategy caused me some grief. Not much though ;D

Having worked on the Walkera 4#3's a bunch, this build was easy, easy. I only cursed the small parts once, which is a record. The hard part was finding everything I need and stopping to take pictures for you guys. The parts tray was a godsend.

As soon as I'm able, and it may have to be done in stages over the next four days, I'm going to post the build. I really took the time to take pictures where I thought someone might want/need/could use an explanation. Way more pictures than my other builds. If I thought about taking a picture, I took it.

ok... so I'm going to get back to finishing this thing off. Please feel free to leaves comments, questions, ideas .... if you want me to do something different. This thread doesn't belong to me. The question not asked goes unanswered!

Robby

[edit]

Wanted to add a couple of pics... couldn't resist:


This is an example of the manual. First build page. The head is most of the way built for you so not a lot of this applies but you can see at the bottom they want you to make sure the links are all sized properly. With this build, you absolutely must have calipers.


I'll edit the size of these later, but this is where I'm at as I type.


Other side

I'm going to break it way down in the following posts so stay tuned!

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[kiwi1080]

That looks like a nice machine!! Out of interest how much did that set you back? Could be a great future project once I get more comfortable following my HB mods. Where did you get it from also?? Thanks.

[Doozer]

Well, the sticker price on the super combo is $429 but after I bought it from Helidirect, I found it a Miracle Mart for $368 shipping was $18 dollars so that put it in the $385 range. Shipping is free from Helidirect, but I would have waited the few extra days to save the $40+ dollars. However, I also bought another $100 dollars worth of spare parts i.e. Blades, tail blades, all the shafts (main, feathering, tail), linkage, control arm balls, belt for the tail... etc. Also, the battery was another $30 dollars (included in the $100 dollars above). The AR6100 rx was $50. So I've got about $580 in the heli. Yes it was. (the answer to the question you just asked).

I could have gone cheaper... with some cheaper servos and a cheaper speed controller, and probably a cheaper motor. But I wanted to experience the "Align" experience just once at least. See what all the Hype is about. Are they overrated... maybe. Do they make a nice product... yep they sure do. I was very impressed with this heli, but then again for the money, I ought to be.

The real reason I came on to post was to say that It's finished and running. I haven't set any trims or set my pitch curves yet. I'm going to go with a normal pitch curve for now since forward flight with a few fast piros is all I have right now. Probably something like a -2 at low stick and 0 at mid stick and +10 at high stick. I'll keep my Idle up curve linear.

Here's a little movie of the first power up:



I will start on the build photos tomorrow! ...(well today actually its early in the morning here).

[rmhovis]

Great pictures and explanations!
Thanks for a great post, helps us new guys to see where all our money will be going from now on! ;D

[Doozer]

Thanks RM,
I try to be clear, but I don't always do things in a linear fashion. It's good to know that someone else gets it. Anyway I'm getting ready to put up the build thread. I'm going to reserve the next four posts for this purpose. Thanks for understanding.

Robby

[edit Feb. 04]
All of the build pics are ready, had to draw arrows on some and resize them all so that took some time. I haven't uploaded them to my personal webspace yet, I'll do that after work tonight. You should start seeing some build photos tomorrow morning.
[/edit]

[Doozer]

Here we go....

First things first, a brief summary of the build. It wouldn't have been easy if I hadn't had a little experience building other easier kits. It's doable for a fresh beginner but you'd have to do a ton of research, and you would need to watch Jasmines videos. Even though Jasmine thinks this isn't a beginner heli, I do think that its a great third heli to buy (Coax, FP, CP). If you've flown any of the Walkera sub micro helis, which I don't think Jasmine has, this little heli is cake to fly. I'll link Jasmines videos at the end of the build, I would disregard her opinion on having to be an experience flyer to own this heli. There are other more technical builds out there, but she makes it very simple to follow her. Take some 5 hour energy though because her voice is quite hypnotic.

The Manual was quite complete. I could have done without all the Chinese writing because that makes it looked a bit cluttered. I understand why they do it though. The cool thing is that you can apply all of the generic heli setup procedures to the 250. So if you've done another set up before this will be easy. Even if you haven't, as long as you get your servos at 90 from the shaft, and your links the correct length, there isn't a whole bunch more you'll need to do.

If this is your first Align, like it is mine, you'll be very pleasntly surprised. But be warned... I was setting up trims in the garage and it started to drift near my workbench so I reduced power... oops didn't set up pitch curves. It was like a huge vacuum cleaner had sucked it to the garage floor. I wasn't used to that quick of a reaction to negative pitch. I broke both skids, with the training wheels on. It hit hard. I didn't do any other damage so I was quite lucky, but don't mess around here, as tempted as you might be to just go fly, make sure you set your normal pitch curves before you fly.

I've set my normal curve to -1 at low stick, 0 at mid stick, and +11 @ full stick. I didn't do any pitch set up photos because there are better videos out there. Nuttcaze's are very good as well as Finless' @ Helifreak. If you have no experience at all, I would suggest, at the very least, that you watch as many of the "101" videos as you can. I will link them at the bottom.
Now for the pics:


Building the flybar cage... don't forget the pushrods or you'll be unscrewing it and rebuilding it again. Also... Metal to metal... Blue locktite is your buddy.


Those bars above go into these. If you're not used to working on sub-micros, these screws can seem small. I mean yeah they're small, but you can see these on the floor. Oh... and that brings me to another point. Make sure to use something like a towel to work on. Screws tend to stay where they fall on a towel. When I'm working with black screws I like a yellow towel. I think it makes them stand out more.


Completed flybar cage. Notice the pool of Threadlock... I lightly spin the first few threads. I also suggest getting some sort of magnetizer or a magnet for your driver. Makes it a lot easier to keep screw on the end of your screwdriver.


This blue driver is the workhorse on this build. I only use the black phillips to mount the servo horns to the servos. Everything else was this driver.


Fairly standard flybar assembly. Two grub screws lock the flybar in place. The manual says 49.50 mm from the beginning of the cage to the beginning of the paddle.


The grub screws are very small.... again, if you're not used to this size have a magnifying glass handy.


Completed head. The manual shows the head exploded, but Align was kind enough to build most of it for you. so the head goes together Fairly quick. After this step you should get your ball links set up. The measurments are in the manual.


The swashplate linkage are all different sizes. Consult the manual. I locked my calipers down then twisted and test fit until I got the right length.


The completed head with links. Align does something cool with their links as well, they put a little "A" on the outside of the link. So you can't get which side goes on the ball wrong.


Next I bound my receiver to my radio. I used this old 7.4 battery pack I had from one of my first helis.


On the DX6i, the trainer switch is your binding switch.


To bind your DX6i plug the bind plug into the "Battery" terminal on your receiver, then just plug your battery in on anyone of the other terminals. I used Aux because its right on the end. Make sure that you pay attention to your receivers polarity. It generally goes signal, positive, negative, but sometimes you don't know which side they start on.


They receiver should start flashing at this point


Turn the DX6i on an quickly pull the "Trainer" switch. This puts your spektrum receiver and transmitter in bind mode. Wait for the rx to quit flashing and let the light go steady. The power off the receiver and the radio, unplug the bind plug, put the battery back on the "Battery" terminals with the correct polarity and you're Spektrum receiver is bound to your DX6i.


Kind of a crappy photo here... sorry... but the point is that you should dry fit your Aileron and Pitch servos. I have Aileron on the right, pitch on the left. In this build you should leave the Elevator servo out. Then plug them all in to the receiver. Give the receiver some power. Make sure to have your radio on and set up for your new heli. Then move your throttle to center stick and test fit your servo horns. Apply sub trim if needed to get the servo horns 90⁰ from the main shaft.

With the power still on, remove the servo horns one at a time and screw in the servo's control balls.


Another crappy photo, but the arrows point to where the sevo gears are. The heli is standing straigh up facing you. That's the rx laying down in the background.


You'll find the servo horns in the same bag as the speed controller and gyro. This was glued to the top of the box.


Screw the balls in on the inside of the horns. Use the outermost hole on the cyclic servos.


Shows the servo horn at 90⁰ Screw in the horn and cut the excess off.


I use a small drop of CA on the very end of the threads so the ball will be more secure.

Ok... stopping here for tonight... will post more in the morning.

[Doozer]

Ahhhh, I have some sleep and some coffee ready to go again. I'm going to go back and edit most of these posts. When I get home from work my mind isn't as fresh as it is when I first wake up. I tend to leave out key words. If I leave you puzzled, please PM me with a correction, because my intent is to be very clear.

With that said, here we go again:


Ok... so now I remember why I left off here last night. This can be a little hard to understand if you haven't worked with a good radio. If your servos don't act as they should i.e. When you give the heli throttle the pitch of the blades will change; All three servos, the Aileron, Elevator, and Pitch will move upwards with stick input. If one or more of those servos does not act correctly (goes down instead of up) it is reversed. I use pitch to check my servo reversing. In this case my pitch servo was correct, but my aileron, and elevator servos were reversed. So I went to my radios "Reverse" menu that's in the "Setup" menu. I reversed both my "Aile" and my "Elev" as you can see. What you don't see is that when I put on my tail servo, it was reversed as well.


Swash mix can be tricky for the newbie to understand as well. This also affects how your servos travel. I use the DX6i, so its default swash mix set up is 60% of the the servos throw. This is a good number to start with as it may have to change. Here's an example: Taking this number that they've given me to start with, when I apply throttle, all three servos are getting a pitch throw command. Their movement is limited to 60% of their total distance either way. When I move my throttle stick upwards, I am now increasing my pitch on the blades. If I end up with a pitch that is higher than recommended, I need to lower the percentage of throw, from 60%, until I get the correct pitch I want for full stick. With a pitch gauge this is a snap to do. If you haven't done a setup before you should watch a "Finless" video on setting up the radio. He uses a different radio than me, but I was able to use the information because most good radios have similar functions.

In this case, When I'd give my servos a roll command, they would throw in a different directions from the command they were given. So I reversed their travel by giving the Aileron a negative number. Depending on your radio and servos, this number will be different for you. Again, don't let me confuse you, watch a "Finless" video.


Q: What the hell Robby, why are you showing us pictures of a screw?
A: Well I spent about 45 minutes trying to figure out how they wanted me to secure the servos. It was really right in my face the whole time, but because of the all the Chinese characters, it was kind of hiding in the clutter. This is the screw you use, and the mounting tab that the screw goes into. I'm going to change this as soon as I can get some screw that fit. A Bolt,washer,washer nut system would be much more reliable that using a self tapping screw into a piece of plastic. It's been my experience that plastic tends to stretch and holes drilled in plastic tend to strip. That's one of the main reasons a plastic tail on any heli is a bad idea. This is not really much of a time saver either because you still have to use needle nose pliers to hold this plastic tab in place while you screw it in... overall I'm not sure this was well thought out.


The arrow is pointing to the plastic tab. It would have been just as simple to use a washer/nut here. Also, there is now a sharp screw sticking out, which is never a good idea. Bad move on Align's part.


WTH, really? Glue over a grub screw? I hate this idea. But rather than wait for a new pinion I went with their game plan. The pinion needs to sit so the shaft is flush with the top of the hole like in the next picture.


Thats how I let it dry. I got a little to much glue on it, but I don't trust metal to metal gluing all that much. If this is like any other "Green stuff" I've used, you can heat it up and pull the pinion off. But man, what a PITA that's going to be. Another not so bright idea in my book.


Now for the skids. This picture shows the end cap for the skid. It sits in the end very loose so you'll need to glue it. They kind of cheaped out on the skids here too. I'm going to either manufacture my own out of fiberglass, or look for a super skid replacement. As I said in the introduction, I've already broken these.


Screws into these holes.


Main Gear placement


This Idea I love. Maybe because I haven't worked with high end helis, but man, I generally swear a whole bunch when I have to put the main gear on a small heli. Not this one.... that screw and washer thread into the shaft like butter. Two seconds and I'm done. No pin or Jesus bolt to mess with.


Boom mount.... I will continue with the boom and tail set up in the next section... stay tuned!

[Doozer]

Last section... At the end I'll put some links to setup movies, and a cost breakdown. I've kind of already done that but I don't think that I've provided enough links.

one more time:


This is the tail. It comes completely built including having the belt installed as well. There is nothing difficult about putting this tail on. The hardest thing was threading the belt through the boom, and that really wasn't that difficult.

First, find the tail push-rod guide, its round with at loop on it, and put it on the boom. Then loosen the bolts on the boom mount. Make sure that you've installed the boom with the two holes toward the tail of the heli. The slot in the boom needs to go toward the nose and to the left (port) side. These two screws shown here need to be taken all the way out.


Line this hole up with the hole in the boom


Attach the Vertical tail stabilizer with the two screws you pulled out from the tail, to the plastic piece that locks the tail in place.


Attach it to the tail. Make sure that the long screw is on top


Thread the belt onto the pulley. Make sure that you get the correct tension. This is important. Much like the belts in your car, there should be enough play for you to press down a bit, but not have it reach all the way over to the other side. You can adjust the tension by pulling out on the tail. Once you get the correct tension, lock down the 8 bolts that hold the boom mount in.


Find the round sliver colored piece in your hardware bags. I've taken it apart already in the picture above. Attach the two top screws to the Horizontal tail stabilizer then attach the top part of the the mount to the fin.


Attach the boom support rods to the side of the mount with the screws provided in the mount.


Here they are together


Attach the rods to the frame here. As you can see I've already begun my tail servo set up. Make sure that you have the push-rod guide nose side of the boom support mount, or you'll be unscrewing the mount and screwing it back in one more time.


The servo push-rod should be 204 mm from the base of the ball links. Because you'll need to slide the push-rod through the guide, you'll need to leave one ball link off the push-rod, and attach it; measure it, while its on the heli. Go through your centering set up just like you did for your servos in the cyclic, and attach the push-rod to the servo.


This kit comes with plastic servo mounts. They sell a few types tail servo mounts for this heli. In the previous pictures you can see that I had the silver metal mounts on the boom. First, I couldn't get them tight enough... Second they were big an bulky and added weight to the tail. I saw some metal ones that look like the plastic kind on helidirects site last night. I'm going to order those I think and make do with the stock ones for now. Again, they kind of cheaped out here.


This is my placement for the gyro and the receiver. I have the terminals of the receiver facing out and toward the bottom of the heli for easy removal and replacement. The receiver's bottom is foam taped to the gyro support platform. It worked out well.


This is how I have the wiring for now. I may try to rewire it. Its not the cleanest job in the world. I'm not into shortening wires so I can say that my wiring job is better than someone else's. I may use those servos elsewhere, and this is a small heli. All the wires are out of the way and fairly neat so I'm happy enough I guess.


Battery and ESC placement. I'll need to vent the canopy if I leave them both here together.


It looks kind of like a transformer here. Sort of crab-like


All done





[edit Feb. 06, 2009]
Quick hover vid:

I would give this heli:

-3.5 out of 5 stars in the quality of parts. Again, don't misunderstand this number. I think that most of the parts are a very high quality, but for the money that I spent, I think they could have done a better job with some things. I really don't want to see any plastic on a heli this size that costs this much. The blades... ok, but I was a little disappointed with the servo mounts and the skids for sure... they suck. I'm tempted to throw 300 size super skids on this.

-4 out of 5 stars in the ease of the build. They put most of this heli together for you. You just have to slide some things in.

-5 out of 5 stars on the manual. I can overlook the Chinese characters... Mainly because I've been manual deprived.

-5 out of 5 stars on the ease of set up. As long as you follow the manuals recommendations this set up was easy.

I'll add more as I start to fly it.

Links:

Where to buy: As a U.S. Citizen I try to keep my money in our economy if I can. Whatever country you're in, its good to try to keep your money at home if you can. This is where I bought this heli. : www.helidirect.com/product_info.php?cPath=29_221_657&products_id=9207

That being said, if they can't keep the price reasonable, they aren't being very patriotic. The price above is, with shipping, $40+ more than here:
www.miracle-mart.com/store/index.php?main_page=product_info&cPath=66_78&products_id=2633

You can speed ship for just another $4 dollars. That means you'll get it in about five days from the ship date. I would have gone this route if I wouldn't have been as impulsive. I've written Sammy @ helidirect and gave him the link to this heli along with the shipping prices. I asked him to lower his prices so it wouldn't hurt so much to buy American. I got no response to this and his prices remain the same. If you want to get it at this price and keep your money in country, I suggest that you send your reseller this link and ask them to match it before you buy. It's the cheapest I've seen yet on the super combo.

I also recommend buying spare parts. I spent a little more that 100 dollars on spare parts before I even put it together. Some gears, belts, all the shafts... I didn't get skids, dumb move now I guess.

Videos to watch, watch as many as you can if you're new:
www.helifreak.com/showthread.php?t=41692

Jasmines 250 build videos:
www.helifreak.com/showthread.php?t=106883

[/edit]

[Doozer]

Just a little more to do here, I just wanted to reserve one more post. Feel free to post at any time.

[Solitaire]

You got that together quite quickly. Such a little cutie, too. Not sure I'd have the patience as I'm sure the parts are even smaller than what we've already been subjected.

What's the length of the boom supports? I know that sounds like an odd question, but I'm looking for something for the Neon and can't find the right length.

[Doozer]

I'll measure them when I get home from work. I broke the CA'd skids again but I hovered a whole pack. Luckily had the training wheels on again. So, I'll be messing around with it tonight.

Got my logitec gyro... smaller than the telebee I'll be throwing it on the 450 tomorrow. Hopefully get some flying done over the weekend.

[edit]

Sol, 190 mm

[/edit]

[Solitaire]

Thanks Doozer.

I wonder if those metal skids from XM would work on that l'il thing.

I didn't figure they could make gyros any smaller than the Telebee. Another one of those situations where you need a magnifier to make adjustments.

I take it you got the Logictec gyro/tail servo deal at RCSupersales.
How does the gyro stack up size-wise against the Align on the 250?

[Doozer]

Not real sure because I haven't used the logitec yet, but I can tell you that the Align gyro GP750 has some very cool featrues. The one I like the most is you can program your tail servo throw limits and it centers itself. This way you can keep the slider from plowing into the hub or the tail. Before I connected the gyro, I had centered the servo horn on the tail servo. I didnt have a horn that would match up just right so I had to use some sub trim to get it 90. When I connect the gyro and set the limits, I had to take all the subtrim out because it was spinning against torque on the ground. So my rudder subtrim sits at 0 with a very quiet tail.

I haven't started any piros yet or setting up piro rates. I've been trying to mend a broken skid. I flew a whole pack yesterday with a broken skid and the tail blades rubbed the ground ever so slightly when it was time to land. I really don't understand how super skids can make a skid that just won't break, and these other heli manufactures don't pick up on that. I mean, yeah I guess I do understand, but the reason sucks. It's a mini cash cow.

Anyway, the GP750 is nice. You can use it on a 450 heli if you set the delay differently. However, my use of it is limited and I really have nothing to compare it to at this point. I need to study gyros a touch more because I'm starting to get beyond the "101" videos.

Thanks for the post. Great to have you here.

Robby

[edit]
Oh... and guys, I'm going to be running back through this thread and cleaning up some disconnected thoughts and try to make sense of some of the babble up above. I worked many hours straight on the build. Then my work week started and I guess my brain wasn't functioning as straight forward as I had hoped it would. So the posts above will change to make things more clear.... I hope.
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