Trex250 Manual

[Jasmine2501]

Could you put two step washers back to back in there to fix it? Or just one?

[ndoren]

Jasmine,

Very interesting idea! Actually, maybe two step washers front-to-front. However, you'd have to make sure the step is just the right height to properly preload the bearings. Too much step, and the there's too much side pressure on the bearings. Too little step, and you still have slop in the races. You could grind down the degree of step as necessary. You'd also need a pretty doggone small step washer, with a 5mm OD and 3mm ID, or something like that.

[thomasgen]

thank you!!

[PlastikPilot]

Originally Posted by jurassic5

Hi bob,

I just did a new version of the PDF manual with the production manual (other one is pre-series)

Please find it there to share with all the HF members:

http://www.gamani.org/trex250/TREX250MANUAL.pdf

Cédric

Looking at the manual posted on this link I see a potential error. The directions for the belt tracking look backwards to me. If this is a clockwise main rotor the tail should rotate CCW up into the rotor wash. The way the manual shows it is reversed.

[Soarmax]

The manual's correct. You're forgetting that the Tail Drive Gear Assy reverses the direction the belt turns. It turns CCW which in turn pulls the belt from the bottom of the Tail Pulley. CW looking from the left side.

[ivc]

I received my T-Rex 250 Super Combo today, and scanned the fresh manual. It's the Feb.2009 revision includes the new tail (1x bearing), longer servo ball head, T22 threadlock, and a few added notes.

Also scanned the GP750 gyro instruction piece.

Both are scanned at 200 DPI and the PDF is created using JPEG high image compression. Zoom to 200% for the real resolution and details.

Downloads:
align-trex-250-supercombo-feb2009-manual.pdf (13.6 MB)
align-gp750-gyro-manual.pdf (1 MB)

Feel free to mirror those.

(as posted in rcgroups)

[Finless]

Special thanks to HF user Average Joe for supplying the latest Trex250 SE manual!

The download link is posted in the first post.

Thanks Joe!

Bob

[dbruncati]

links not working any ideals

[HelloJim]

Thanks for all the help in so many areas. I'm new here and new to rc helicopters. I've got it bad though, spending way too much money getting started.
Have a new EXI plastic I need to build and a new CopterX 25-se on the way. Found some T-Rex 250 manuals here. Hoping I can follow them!
Thanks to all for the help, hopefully, I can contribute to the forums in the future after getting more experience.

Jim

[Steve Joblin]

The manuals will be very helpful, but do note that there are a few very slight differences.. you may find that the CopterX has an extra washer here or there, or that the manual refers to inserting a spacer or something that the CopterX does not use. They are extremely similar, but there are a few small differences.

[zambz]

Nice manual.

[applegeekz]

Thank you so much

[CyberPlainsDrifter]

Ive got a manual dated April 2010. is this useful and if so how do I get it "out there"?
If you can read the bloken engrish...that is...

Im not so sure Im likin' this bird so much. The tail blade holders are loose and very sloppy. Theres only one bearinge per grip.... Is this the "new" set up or the "old" set up?
Remeber that movie "wag the dog" ? well waht about Wag the bird? I thought I had it covered but I was mistaken. This bird wanders to the left in headlock and wander to the right and REALLY wags when in normal mode. ~sigh~ Speaking of which. Im having difficulties with setting up the GS780 in combo with my DX7 Ive looked high and low for a thread or vid... and I cannot find anything.. so... I post it here... Haaaalp!! : ) please.

As well, Ive found a number of threadlocked/stripped screws (from the factory) that I cannot remove... ~sigh~ So how is a guy s'posed to dismantle this thing with out destroying original parts?

Someone, please tell me that I didnt make a mistake buying this machine. I Thought Align was a good , reliable and quality manufacturer. This 250 'o mine seems like it was slapped together and put into a fancy but tiny box. The bottom plate doesnt fit well and needed to be filed. (no biggy but....) some of the more important threads werent secured with Thrdlck and others were stripped and are not removable... What gives?
I spent good money on this thing.. - as another member so eloquently put it.

[Jasmine2501]

It's a good heli but it's picky about some things and it does not tolerate he-man torque values. Be gentle with those little screws - hold the screwdriver with one finger and thumb and tighten it that way. I'm pretty convinced most of the problems people have with the screws are due to over-tightening - since I've had my 250 almost two years and have only stripped the heads on the screws in the tail, and it was totally my fault.

The tail drifting is just because your setup isn't quite right yet. This bird is very sensitive to super-small adjustments, so you're going to need to fly it to get the final adjustments - eyeball gets you close, but not quite.
[ame]http://www.youtube.com/watch?v=_W7lLEuFSds[/ame]

[CyberPlainsDrifter]

Hi Jasmine, Thanks for the advice.. I am aware.. Tiny screws tiny torques. Its not me however.. I was fidling with the butt end of the machine last night and discovered all these foo foo's.... ~From the factory~ So ... WTF??? (thats "why the face" to those of you not in the know... -see avatar)

Anyway.. I will watch this vid you've pasted in. My gyro is a 780. Is the set up the same as the 750? I guess watching the vid should answer that huh? Duh...

Thanks for the link to youtube.

[Besen]

I had a drift problem in HH and re-binding fixed it.

[Jasmine2501]

Originally Posted by Besen

I had a drift problem in HH and re-binding fixed it.

Yup - typically this happens when you have entered some trim on the rudder channel. If the rudder channel position differs from that which you bind with, then the gyro sees that trim as an off-center signal, like you're holding the stick a little off center, and it gives you the slow turn you're asking for.

Remove the trim from the rudder channel and re-bind - this should set the fail-safe and the operational center to be the same, so the gyro won't initialize with one value and then see another value after the radio connects.

The problem here is the value sent on the rudder channel during gyro initialization, which usually happens before the radio connects, causing the gyro to read the receiver's default value as the center of the channel. Then the radio connects and you're sending some different value, which is seen as a request to turn.

[Besen]

Just to be clear, you can have sub trim and bind successfully. Also, I think other things, like tail geometry changes, will cause drift that can be corrected with re-binding. For the record, I have a Dx6i and a GP750.

[Jasmine2501]

Originally Posted by Besen

Just to be clear, you can have sub trim and bind successfully. Also, I think other things, like tail geometry changes, will cause drift that can be corrected with re-binding. For the record, I have a Dx6i and a GP750.

There isn't any difference between sub trim and regular trim - they both change the center of the channel. The 'lucky' difference that most people see with it is they just happened to do a re-bind after they put in the sub-trim - which re-centers the receiver default. Changes to the mechanical center won't affect a heading hold gyro's ability to hold position, but it can change the piro rates on either side if you get the limits off center.

With a heading hold gyro, your rudder input is interpreted as a request for a particular action to happen (turning, or holding) - it tries to satisfy that request by moving the servo around, and wherever the servo ends up is none of the pilot's concern, usually. This is very different from all the other channels on the helicopter, where we are telling the system to move a servo to a specific spot, regardless of the effect of that control surface change. The gyro is very special - you request a specific result and you don't control the servo position.

The problem here is not the trim or the mechanical setup itself - it's due to what the outputs of the receiver are sending BEFORE the radio connects. This can be different with various receivers or radio systems. The most common issue is that Spektrum systems don't connect immediately, the receiver has to look around and find its radio - during that time it is sending a default rudder position signal to the gyro, and most gyros finish initialization before the receiver connects - so they never get to see the value that the radio is sending until after initialization. That "after connect" value can be pushed off-center by sub-trim, and if it differs from the default receiver value, then it will be interpreted as a request to turn.

Remember, the receiver just gets a number, like 100... that's it. It doesn't have any way of knowing that the 100 is really 95 input and 5 sub-trim. It just sees 100. Wrap your head around that and a whole lot of confusing crap about these systems becomes really clear.

Your radio sends six numbers to the receiver - that's it, that's everything.

[heli tas]

what would cause receiver light to stay on steady when the bind plug is in spertrum ar6100 and is there a better receiver then this for the trex 250 any anwser will help this my first project