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700 Class Nitro Helicopters 700 Class Nitro Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 12-02-2008, 11:54 PM   #1
HeliSmith
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Default Issues with Trex 700n to keep an eye on!

We owe it to the guys after us to report what we have heard or experienced. Not to spread rumors or fuel panic but to just let a guy know what to watch out for. I would like to know if I am missing any too. Most of this information has been reported to me by others or on this forum. Most of it is not personally verified.

Links shouldn't be flown near freezing. (Myth?) swapped to QuickUK forget it.
Main gear is definitely failing perhaps more under near freezing. Mine is not wearing funny though.
Don't leave your tank empty or the seals will leak. (Bad practice anyway)
Start with a thin main shaft spacer and end up having to use a thicker one (Mtyh?)
Head button known to strip threads. Red thread lock or Epoxy is a good preventative step.
Head button said to cause more damage in a crash and a 500 head button can be used but I didn't.
Stock paddles will probably slip, Epoxy is a good bet I used blue thread lock.
Stock tail blades could fail if they have a lose eyelet so check it.
Governor mount holes might need to be elongated to be 1mm for the sensor.
Frame screws could be impossible to remove if you use lots of thread lock.
Tail rotor could possibly come apart if you push the envelope with head speed.
Probably a good idea to pin the boom at the boom block, no reported failures I seen yet.

Undeniable problems / Can't be build related
Crooked links on early kits
Untrue clutch / weak clutch materials *** Be ready to auto ***
Dust cover on swash plate won't last 5 flights. (Who test flew this one guys?? lol)
Boom notch could be off center and need to be filed to get tail straight.

I am very happy with my Trex 700 and I maintain even with the problems I am glad they released it now.
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Old 12-03-2008, 12:15 AM   #2
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Quote:
Originally Posted by HeliSmith View Post
We owe it to the guys after us to report what we have heard or experienced. Not to spread rumors or fuel panic but to just let a guy know what to watch out for. I would like to know if I am missing any too.
Good list based on what I've read here. Here's my experience in each case.

Quote:
Links shouldn't be flown near freezing. (Myth?) swapped to QuickUK forget it.
Main gear is definitely failing perhaps more under near freezing.
Have to take everyone's word on this one. I fly in sunny California and I have never had a link or a main gear failure. After reading so many stories, though, I did chicken out and put the QuickUK links and balls on the grip links only. Cold weather will eventually find us soon, even in NorCal. We'll see.
Quote:
Don't leave your tank empty or the seals will leak. (Bad practice anyway)
I now fill the tank at the end of a flying day and then empty it to expel exhaust gases. I recently disassembled my tank and the original Align clunk line is in fine shape and I didn't even have to replace the fuel magnet. The stopper almost seems softer than when new and a little puffy. Good seal, though. All fuel so far has been Byron 30% heli. My first tank of Coolpower will be next week.
Quote:
Start with a thin main shaft spacer and end up having to use a thicker one (Mtyh?)
Okay, similar experience here. I started with no shim. After a few flights, I added the thinnest one. I had to bevel the ID and sand it down a bit to get the right fit. No change since and the fit is still perfect.
Quote:
Head button known to strip threads.
Not yet here. I installed my button when I built it and have used it to stop the blades on every flight since. No problems yet.
Quote:
Stock paddles will probably slip.
No experience here. Went right to Super Stubz, out of the box.
Quote:
Stock tail blades will fail if they have a lose eyelet so check it.
Radix 105's from day 1.
Quote:
Governor mount holes to be elongated to be 1mm for the sensor.
I saw this in Finless build video. However, I measured the spacing between the magnet and the sensor on mine and it was well within the 2mm maximum. I'm using the Align sensor with the MultiGov Pro governor.
Quote:
Frame screws will be impossible to remove if you use thread lock.
If you keep the blue locktite down on the last 2mm or so of thread, you get a tight fastener that is easily removed. I was a little too locktite happy on the first go round and removal was indeed difficult.
Quote:
Tail rotor could possibly come apart if you push the envelope with head speed.
I believe that well designed tail grips have 2 radial bearings and a thrust bearing. Based on my experience with my 600E, QuickUK from day 1.
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Undeniable problems / Can't be build related
Crooked links
Got lucky. Mine were all straight. My kit was from the very first batch. I paid an idiotic price for the first bird on eBay.
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Untrue clutch / weak clutch materials *** Be ready to auto ***
I practice several autos every trip to the flying field. No clutch failure yet. I did replace it after a hot start but that was over 20 flights ago.
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Dust cover on swash plate won't last 5 flights.
I've read about this one but mine seems to be stuck in place very well. No sign of it falling out yet.
Quote:
Boom notch could be off center and need to be filed to get tail straight.
I didn't file mine but if you close one eye, squint, and concentrate carefully, it might be just a smidge rotated. No effect that I can tell on flying.
Quote:
I am very happy with my Trex 700 and I maintain even with the problems I am glad they released it now.
Agreed. I'm not looking for perfection. Making things work well is part of the joy of the hobby for me.

Me baby here:
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Old 12-03-2008, 12:20 AM   #3
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Nice addition cdbane and yeah my friend didn't elongate his governor mount hole either and his seems fine.

I love that canopy! Heli looks nice!
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Old 12-03-2008, 02:21 AM   #4
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Your missing one:

Check if your maingear can move up/down about 1mm (obs not tail gear),
If it can, Loctite residue from the factory has wedged between the upper bearing (inside the one-way unit) and the unit itself, so the upper bearing is not seated fully in.

Solution: Take it apart, clean, reapply new loctite & put together.
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Old 12-03-2008, 10:09 AM   #5
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Nice I forgot about that and also I took apart everything they put together. I cleaned thread lock out of my lever arm bearings and other places too.

I did take apart my one-way as I trust no one. Finless pulled it apart in the video so I took that thing apart, cleaned it up and added quality bearing grease.
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Old 12-04-2008, 10:07 PM   #6
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The only problems I've experienced;

Lost the dust cover on the swashplate 2nd flight.
Fuel tank leaking. I fuel the heli once a week or so weather I fly it or not, and haven't had any problems since.

Other than that I had a tail glitch, not a wag, but a twitch. ( looked like a bad servo )I went through every bearing, linkage, and setting. Finally replaced my gyro (Fut. 611) and the problem was solved.
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Old 12-05-2008, 05:34 AM   #7
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Quote:
Originally Posted by bloftin View Post
The only problems I've experienced;

Other than that I had a tail glitch, not a wag, but a twitch. ( looked like a bad servo )I went through every bearing, linkage, and setting. Finally replaced my gyro (Fut. 611) and the problem was solved.
I too had this with a 611 on my 600, interesting!
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Old 12-05-2008, 10:56 AM   #8
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My only problem! was the bad link, who was replace by Readyheli, I fly my 700 hard, i never add any problem!

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Old 12-05-2008, 12:50 PM   #9
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I too had this with a 611 on my 600, interesting!
Similar here. I had a drift at the top of loops with the 611. I replaced it with the Spartan and problem was solved.

My theory: the gyro sensor mounting location in the 700 is too close to the two aileron servos which, with modern high current servos, may cause electrical interference. The 611 manual talks about keeping adequate distance between the gyro sensor and possible sources of eletrical noise. Along these lines, I think that my drift in loops was related to the head collective adjustment (servo motion) as I went over the top. Somehow, the Spartan seems more immune.
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Old 12-05-2008, 01:08 PM   #10
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Did you use a metal plate between the sensor & servo, that helped on my Stratus when I had the same problem (different gyro though)
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Old 12-05-2008, 10:40 PM   #11
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Did you use a metal plate between the sensor & servo, that helped on my Stratus when I had the same problem (different gyro though)
I used the metal plate on mine. Remounted the gyro, changed settings, replaced the one way bearing, inspected every bearing from front to rear (all smooth), upgraded to a metal tail, ran different head speeds, tuned the motor, and nothing worked... until I replaced the gyro. I went back on with another brand new 611 (wish I had a Spartan) and it flies great for now, but if any new issues come up I'll keep you guys posted.
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Old 12-05-2008, 10:50 PM   #12
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Geez what a headache to find out it was a gyro who would have thought though. Glad you have it sorted out.
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Old 12-06-2008, 04:15 PM   #13
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+1 w/ the twitchy 611 here too! It's anoying to say the least but I don't really hover much anymore. I'm kinda waiting for the GY520 to solve the problem.
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Old 12-06-2008, 04:24 PM   #14
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I am having 0 problems with my 611 this thing is locked in so tight you guys. I never even had the slightest bit of trouble setting this thing up even when I bog it the tail holds like on rails.

Really sorry to hear that isn't the case for you. I'd be happy to share settings if that might help running DX7, 1950 headspeed, 50 gain on gear channel that is all I can remember without looking.
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Old 12-06-2008, 07:26 PM   #15
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Mine too holds great in everything but the hover where it just twitches slightly. I'm running 38% gain with 100% travel on the 611 screen. Could still be en engine tuning thing but it flies great w/ fistfulls of power. Dunno what the problem is...
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Old 12-07-2008, 05:11 PM   #16
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Is it ok to still fly without the dust cover?
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Old 12-07-2008, 05:16 PM   #17
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Is it ok to still fly without the dust cover?
I still fly without mine, couldn't tell you how many flights I have on the bird, but no problems so far. I do put a drop of oil on the swash bearings every so often.
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Old 12-08-2008, 12:55 AM   #18
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Well my Rex has been well behaved Links good, swash good, fuel tank good, main gear good, gov mount all GOOD, but the clutch. I just snapped another one this weekend. Does anybody know if there is an upgrade clutch or if a clutch from another machine will work on the 700.
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Old 12-08-2008, 01:49 AM   #19
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Well my Rex has been well behaved Links good, swash good, fuel tank good, main gear good, gov mount all GOOD, but the clutch. I just snapped another one this weekend. Does anybody know if there is an upgrade clutch or if a clutch from another machine will work on the 700.
There are rumors of a new one from QuickUK on its way.
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Old 12-08-2008, 03:31 AM   #20
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+1 w/ the twitchy 611 here too! It's anoying to say the least but I don't really hover much anymore. I'm kinda waiting for the GY520 to solve the problem.
yep, I wouldnt buy another 611, spartan all the way now, I have a feeling the 611 is susceptible to damage in a crash as mine was fine until after its first crash, then i got the twitching, swapped out for a spartan and all is good!
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