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250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 04-01-2018, 04:22 PM   #61 (permalink)
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I may have made progress...

I tried feeling what the servo feels when up to speed. Unhooked pushrod from servo and spooled it up using fingers as servo.

DAMN! That servo works ITS ASS OFF. Makes me wonder how stiff other tails are. My whole pitch linkage chain is quite loose and floppy but just even at mid throttle I was like, damn!...at 3/4 throttle I had to rearrange my hands/the model to grip everything better to be able to move pushrod. So stiff I thought it was seized out at one point but its just that stiff under force. Excellent learning moment. I now understand the benefit of a better tail servo AND the Chinese weights.

Changes:
*Assembled blade grips properly.

Fearing my arbitrary anti-slop washer was at least a contributor..I got into new parts that I was in the return pile. Of the two ways to assemble bearing grips I went with the two smaller bearings separated by the washer (old way?) instead of one bigger bearing with washer (new way?). Results were surprisingly nice. Only tiny bit of acceptable slop but more importantly it's now closer to OEM than with my washer. Maybe it matters under force.

* Went back to bat wing tail blades

My 250 does not like the KBDD rectangle blades. At the either extremes of movement..the pitch would get smidge tighter then POP FULL. (I doubt my recent flying style ever took pitch slider to its full extreme but obviously something wasn't right)
Put old bat wings back on and now maybe only a smidge easier to move pushrod but more importantly..no full pitch pop at extremes.

First flight after:
Gyro up to 30 (which is nuts for me..usually around 17)
No wag!
Gyro over 30
Wag returns

Optimism. I can live with this (for now anyway)
Second batt charging...

If second batt confirms progress I'll return (at least) the aluminum pitch slider in exchange for metal pitch arm and a lynx blue arrow digital servo. If I'm this close..the new faster servo should seal the deal.

I'm thinking the rectangle blades were my biggest problem.

Last edited by Tech 4 9; 04-02-2018 at 12:22 AM..
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Old 04-01-2018, 05:46 PM   #62 (permalink)
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Second batt:

All was fine...
Playing with tail..refining gyro settings...tail input input left then right..over and over..adjustments..
...at one point, tail input caused whole model to balloon up somethin fierce. Pop up is more like it. In my living room. So fast I thought it was gonna go through the ceiling.

Panic ensued.
Lost it.

Boom strike...feathering shaft..main blades...battery tray..boom support...blade grip...two holes ripped in cf panels...

Finally lost some wag only to have it replaced with this psychotic, unpredictable ballooning/pop up shit.

This is nuts.
Decision made.
Life is to short to own a t-rash 250.

Done.

Everything that's 250 and returnable is going back to fund rebuild of it AND fix the 150x.

F. U. T-rash 250,
..even my nano cp flys better than you.
Get out of my house so that 'fun' will return this hobby.

Due to Align repairs denting budget...
Now considering Blade 180cfx

Last edited by Tech 4 9; 04-01-2018 at 06:58 PM..
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Old 05-23-2018, 07:55 AM   #63 (permalink)
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OP I understand your frustration...................

Save up some money and grab an oxy 2 plastic edition.

This is coming from a guy that hates micro helis.

I took a gamble getting an oxy 2 and it paid off for me.

It is a no maintenance heli with a great tail.

Stick with the Lynx package deal electronics you can buy for it and you can't go wrong. Lynx cyclic servos, blue arrow tail servo and Lynx eox motor.

Oxy 2 flies great for it's size

Oxy 2 crashes very well. It is built like a tank
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Old 01-08-2019, 02:04 PM   #64 (permalink)
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For what it's worth, after a year of messing with mine I was able to get it flying without issues. Here was my journey.


Align Trex 250 DFC
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Old 01-16-2019, 08:17 PM   #65 (permalink)
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Quote:
Originally Posted by flyingaoc View Post
For what it's worth, after a year of messing with mine I was able to get it flying without issues. Here was my journey.


Align Trex 250 DFC
Well...I'll consider this a honor of sorts and take opportunity to compliment you. Excellent write up.
It was your write up that taught me how to make the custom tail pitch rods!
Thank you!
I've learned a ton in the last year and I'm fairly ashamed of this thread. It was mostly borne out of ignorance and emotion. The RC Heli hobby has taught me a lot...and a little about rc helis, too.

Still have the 250. I didn't kick it out after all.
After learning about the Chinese weights and 80 dollar tail servos I saw little point in continuing anything without solving tail issue.

So I 86'd it. Figured out the the Lynx 180 cfx belt tail would replace stock.

Wow. Tail issue solved. 30 dollar tail servo. Between that, replacing BX with Brain and getting it out of house (frigging idiot) I've had two very successful test flights with it. I say test flights because..the journey continues.

The only issue I have now, and quite interested in solving since tail issue is solved, is that collective is wierd around center stick. If I'm decending and want to arrest decent I have to give quite a lot of up-stick just to see decent lesson let alone cease then more to acend. Now it's acending and the reverse process is needed waayyy down with stick..maybe a 1/5(?) into neg before it even responds. There's no controlled hover around 1/4 pos pitch it's just all up and down...up and down. It's literally like dead stick from 1/4 pos to 1/4 neg.
My head geometry is in question. For one I'm using emax cyclics. The specs are comparable to stock without considering torque. Noob that I was then I only considered speed and 'digital metal gears'. They may actually be fine but the truly suspect aspect of them is the fact the I have the pitch and aileron servos mounted inside the frame because the link balls can't be mounted on inside of servo horn. I rationalized the inside mount would make up for the ball revearsal. So, this all equals dubious head geometry. It LOOKS darn proper..minimal slop (ain't no oxy)..just can't think of what else would be causing pitch issue. Blade tracking was good.

Planning $30 kst servos for this spring. Get em outside the frame..balls inside..more to spec. See if pitch issue remains.

There's no money in selling it and the worst part..tail..is solved so what's another $100 into it. (frigging idiot). It's soooo close.
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Old 01-16-2019, 11:03 PM   #66 (permalink)
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Please elaborate on the 180 tail for me. I've been fighting the bad 250 tail for ever. First it was wag got that sorted with chinese weights, new tail rod ect. Then it would only piro smooth in 1 direction and was notchy in the other. I finally got the tail sloppy lose and went to the non weighted grips and fixed the tail for the most part. The weighted tail grips were hitting and binding on the hub.

The next issue that pops up for me is the OWB after a few hard flights the OWB starts to slip on me and I get a yo-yo like effect on the collective. Needles to say after hamfisting it so its stuck now I can get smooth collective.

With all that in the bag the next problem I keep running into is the pinion keeps popping of the motor shaft. I even roughed up the shaft the last time and cleaned with alcohol be for loctite was applied.

The only bright side to it is I now hate the 250 so much that I flog and fly it like I just dont care anymore because I dont. I'm considering going to an oxy2 but wonder if a small heli will ever be worth messing with again. The only thing that keeps the 250 out of the coffin is that in the past 4 crashes there has been 0 damage what so ever. I'm going to give it 1 more shot with the OWB locked solid, a bigger pinion, and possibly a new tail if the 180 setup is possible.

As to your pitch issue try running a bit of an s curve on the pitch channel. 0 30 50 70 100. Also I found the OWB to be problematic for me and the rotor grip bearings get notchy as well.
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Old 01-17-2019, 01:14 AM   #67 (permalink)
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Tech 4 9,

I had a similar collective issue around kidstick with my Oxy 2. Perhaps my experience can help you on your heli.

My Oxy would be descending, then I’d give positive collective but wouldn’t see anything happen. Eventually, with enough collective or after kissing the ground, the heli would jump up, and it’d be difficult to get it to hover. Up, down, up down. Like I didn’t know how the collective stick worked.

My issue was that I installed my thrust bearings backwards in the main grips. Very hard to visually tell that it was backwards. Only 0.2 mm difference in race diameters. This assembly error on my part was causing some binding at running RPM, not at all present when at rest.

I suggest disassembling main grips and checking everything carefully.
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Old 01-17-2019, 01:19 AM   #68 (permalink)
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I have one of the original Trex 250's from when it was first released.

I wrestled with the tail, as many others stated above. I even gave up and set it aside for a few months.

Then I saw videos of people flying and enjoying them, so I gave it another shot (I wondered what the knew that I didn't).

The first thing I did was to change the tail rotor grip/bearing assemblies (I started with the first generation tail assembly, then ended up with what I believe is the third generation-the one with the large Chinese Weights).

I put it together and found points were it would stick. Took it apart and went through it again, then a third time before I got it right.

I installed a JR 3500G tail rotor servo (almost as big as the canopy it seems).

I made sure that the ball links were absolutely smooth.

I then installed KBDD Tail Blades.

After getting the tail right, I upgraded to an FBL head (right before the DFC came out). FBL unit is a first generation BeastX.

Ever since then, it flies very well, and has a solid, predictable tail.

I apologize for the geezer flying (I am an old geezer), but you can see from the video that the tail holds well with good control with the KBDD Tail Blades. A friend of mine (CARBHEAT911) took the video and composed the music for it.

Align T-Rex 250 Dance (3 min 17 sec)
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Old 01-17-2019, 08:46 AM   #69 (permalink)
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Quote:
Originally Posted by Tech 4 9 View Post
Well...I'll consider this a honor of sorts and take opportunity to compliment you. Excellent write up.
It was your write up that taught me how to make the custom tail pitch rods!
Thank you!
I've learned a ton in the last year and I'm fairly ashamed of this thread. It was mostly borne out of ignorance and emotion. The RC Heli hobby has taught me a lot...and a little about rc helis, too.

Still have the 250. I didn't kick it out after all.
After learning about the Chinese weights and 80 dollar tail servos I saw little point in continuing anything without solving tail issue.

So I 86'd it. Figured out the the Lynx 180 cfx belt tail would replace stock.

Wow. Tail issue solved. 30 dollar tail servo. Between that, replacing BX with Brain and getting it out of house (frigging idiot) I've had two very successful test flights with it. I say test flights because..the journey continues.

The only issue I have now, and quite interested in solving since tail issue is solved, is that collective is wierd around center stick. If I'm decending and want to arrest decent I have to give quite a lot of up-stick just to see decent lesson let alone cease then more to acend. Now it's acending and the reverse process is needed waayyy down with stick..maybe a 1/5(?) into neg before it even responds. There's no controlled hover around 1/4 pos pitch it's just all up and down...up and down. It's literally like dead stick from 1/4 pos to 1/4 neg.
My head geometry is in question. For one I'm using emax cyclics. The specs are comparable to stock without considering torque. Noob that I was then I only considered speed and 'digital metal gears'. They may actually be fine but the truly suspect aspect of them is the fact the I have the pitch and aileron servos mounted inside the frame because the link balls can't be mounted on inside of servo horn. I rationalized the inside mount would make up for the ball revearsal. So, this all equals dubious head geometry. It LOOKS darn proper..minimal slop (ain't no oxy)..just can't think of what else would be causing pitch issue. Blade tracking was good.

Planning $30 kst servos for this spring. Get em outside the frame..balls inside..more to spec. See if pitch issue remains.

There's no money in selling it and the worst part..tail..is solved so what's another $100 into it. (frigging idiot). It's soooo close.





You're welcome and I'm glad that I could help a little at least. I'm no where near a pro flyer, but I'm happy with my 250 after all that. I have to admit that it was a great learning experience for a first build and after all that I'm quite attached to her for all the lessons she taught me. Like others said there's nothing wrong with taking a break from it and coming back to it. After all, it did take me over a year to get her flying decent.
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Old 01-17-2019, 11:46 AM   #70 (permalink)
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Quote:
Originally Posted by HeliLust View Post
Please elaborate on the 180 tail for me. I've been fighting the bad 250 tail for ever. First it was wag got that sorted with chinese weights, new tail rod ect. Then it would only piro smooth in 1 direction and was notchy in the other. I finally got the tail sloppy lose and went to the non weighted grips and fixed the tail for the most part. The weighted tail grips were hitting and binding on the hub.

The next issue that pops up for me is the OWB after a few hard flights the OWB starts to slip on me and I get a yo-yo like effect on the collective. Needles to say after hamfisting it so its stuck now I can get smooth collective.

With all that in the bag the next problem I keep running into is the pinion keeps popping of the motor shaft. I even roughed up the shaft the last time and cleaned with alcohol be for loctite was applied.

The only bright side to it is I now hate the 250 so much that I flog and fly it like I just dont care anymore because I dont. I'm considering going to an oxy2 but wonder if a small heli will ever be worth messing with again. The only thing that keeps the 250 out of the coffin is that in the past 4 crashes there has been 0 damage what so ever. I'm going to give it 1 more shot with the OWB locked solid, a bigger pinion, and possibly a new tail if the 180 setup is possible.

As to your pitch issue try running a bit of an s curve on the pitch channel. 0 30 50 70 100. Also I found the OWB to be problematic for me and the rotor grip bearings get notchy as well.

https://www.helifreak.com/showthread.php?t=812511

Start at post #7
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