Attention 120SR Fly-Away "Victims" - Please Reply

[poor_red_neck]

In Lieu of the thread "120SR Flew Away (http://helifreak.com/showthread.php?t=395724)" I'd like to make this poll.

I do not personally own a 120SR, but I'm just curious to figure out what is causing it, whether it's TX related, 5 in 1 related, and if so what component. If you haven't been following the thread, the synopsis is this:

The heli will suddenly goto full throttle, and you lose all control. If all things were working correctly, you should be able to turn off the TX, which will enable the factory set failsafe of 0 throttle, and she should fall onto hopefully soft terra firma.

There are many things that could be causing this, but I would put my money on all these being related to one.


So if you don't mind taking the time to just give me some basic details on your setup, to find the common denominator. The other thread has got a little too cluttered.

Transmitter: Stock RTF TX, DX6i, DX7, DX8, etc etc
Did you lose all control? Did your heli start pirouetting?Did the heli retain tail authority while the TX was on? Did you turn off the TX and then the heli started pirouetting or the second it went full throttle it started spinning and lost all control. If you can remember, try and specify the "timing" of the events, and any actions you took.

(If your heli was recovered)
Did unplugging/replugging fix the problem? IE: It either goes full throttle as soon as you plug it in every time, or it re-started the next time with no problem.

Thank you very much for your time! Try and keep this thread clean. If you want to further discuss, and read up on the number of "reports" follow this thread:

http://helifreak.com/showthread.php?t=395724

[Imzzaudae]

My 120SR flew away twice on me. Both times I was using a LP5DSM. Both times I was no more than 10' from the helicopter when it went full power and flew off uncontrollable.

I blamed the TX but I just do not know for sure.

[chuck1073]

I've had one flyaway. TX was a DX6i in "acro". Unplugging stopped the heli once caught. Re-binding solved the problem.

I did write to HH. They said that "was a new one" to them and to make sure my TX batteries were charged. I think when I had the fly away the batteries were down around 4.6v. I try to keep it up around 5.0 or better now. I'm also flying it in a mostly unmodified "heli" tx profile now so that I have the throttle hold switch available.

[nbells]

I had a fly away last summer.

The heli was flying no problem when all of a sudden it went full throttle and took off, but as the battery was almost run out and flight stability was not controlled it soon fell to earth at full throttle.

I watched it do the funky chicken on the ground for a few minutes before stopping it with a size 9 boot. :wow2:

After some small repairs and a rebind, the problem never occured again.

I put it down to low TX batteries, I was using my DX6I at the time.

nbells

[Heli-cat]

I did write to HH. They said that "was a new one" to them....

perhaps HH should try monitoring the RC forums a bit....well, perhaps not - they might learn of something they don't really want to know about ;)

[GSPI]

perhaps HH should try monitoring the RC forums a bit....well, perhaps not - they might learn of something they don't really want to know about ;)

...actually... they are monitoring... I've seen them post on here before.

[SoccerDadof2]

Transmitter: DX6i

Series of events:
Stable hover at approx 6'. I applied a small increase in throttle, however the heli's response appeared to be that it went to full throttle and heli started climing very quickly as it piroetted. No response to any TX input. Heli got to approx 35-45' when it stopped climbing. As the piroetting slowed (then stopped), the heli transitioned to FFF (still not responding to TX) then as it was entering into a nose dive, it slowly keeled over onto right side. I watched in shock as it Impacted the ground at full throttle.

As part of my occupation, I had worked with gyro inertial trackers and it appears as though the gyro lost orientation to its coordinate system [ie, first rotated around z, then pitched forward (y-axis), then onto side (x-axis)].

Damage incurred: Broken frame. Destroyed right skid. Destroyed canopy. Destroyed CF canopy mounting rods. Battery mount broke into three pieces. Damaged battery. Broken blade grips, broken swashplate.

Contacted Horizon Hobby; they were good in that they replaced the 5-in-1 board. However, the cost of all the other damaged parts tempers their generosity given what appears to be something that is not just an isolated case.

[Pfloyd]

Maybe we need to install chips like they do on dogs and cats....then we can have the pet people find our helis...just a thought.

[Drivinfast247]

Transmitter: DX6i

Series of events:
Stable hover at approx 6'. I applied a small increase in throttle, however the heli's response appeared to be that it went to full throttle and heli started climing very quickly as it piroetted. No response to any TX input. Heli got to approx 35-45' when it stopped climbing. As the piroetting slowed (then stopped), the heli transitioned to FFF (still not responding to TX) then as it was entering into a nose dive, it slowly keeled over onto right side. I watched in shock as it Impacted the ground at full throttle.

As part of my occupation, I had worked with gyro inertial trackers and it appears as though the gyro lost orientation to its coordinate system [ie, first rotated around z, then pitched forward (y-axis), then onto side (x-axis)].

Damage incurred: Broken frame. Destroyed right skid. Destroyed canopy. Destroyed CF canopy mounting rods. Battery mount broke into three pieces. Damaged battery. Broken blade grips, broken swashplate.

Contacted Horizon Hobby; they were good in that they replaced the 5-in-1 board. However, the cost of all the other damaged parts tempers their generosity given what appears to be something that is not just an isolated case.

I thought they were talking abouy the 120sr? That doesn't have a 3 axis gyro.

[Heli-cat]

...actually... they are monitoring... I've seen them post on here before.

They only post after they announce the latest release. Once it's out and people start posting about the issues they're experiencing, they seem to magically vanish....it's really strange :thinking

[SoccerDadof2]

I thought they were talking abouy the 120sr? That doesn't have a 3 axis gyro.

That may be the case; just describing the events.

In my past work history, I worked with mems gyros for helmet/head tracking applications. Because of where we were operating (inside a big metal vehicle) the magnetic tracker wouldn't work, and the gyro would lose orientation. We wrote a utility that monitored the data coming off the tracker. The behavior of the 120SR duplicated the typical observation as the coortinate system searched trying to establish orientation.

Sorry for the long description - I don't know what the 120SR comes with on the 5-in-1. Thanks for your info. Can you give me any insight what level of stability the 120SR has or how it is achieved?

NOTE: Moderator - if this is cluttering the forum too much, please move to the alternate 'fly away' thread.

[jackovart]

it happened so fast i can hardly tell what happened, but one day i was flying from inside the house looking out a glass door. using stock tx and about 90 feet out. i went full throttle to avoid a ground strike, when i pulled back on the stick the throttle never released. it just kept going. it clipped the top branch of a giant oak tree in my back yard and crashed to the ground, otherwise i fear it would be gone. the only damage was a snapped main blade and cracked canopy. it is the only time it has ever happened, i still fly it every day.

what are the possibilites of interference with 2.4 GHz. i was very near some high power lines, if that could mean anything. i really want to know what is going on here, i hate flying in fear this will happen. i don't fly from inside anymore, and am using a dx4e now.

[Heli-cat]

oh man, I would never fly from inside the house! I wouldn't be comfy with that at all :wow2:

[poor_red_neck]

That may be the case; just describing the events.

In my past work history, I worked with mems gyros for helmet/head tracking applications. Because of where we were operating (inside a big metal vehicle) the magnetic tracker wouldn't work, and the gyro would lose orientation. We wrote a utility that monitored the data coming off the tracker. The behavior of the 120SR duplicated the typical observation as the coortinate system searched trying to establish orientation.

Sorry for the long description - I don't know what the 120SR comes with on the 5-in-1. Thanks for your info. Can you give me any insight what level of stability the 120SR has or how it is achieved?

NOTE: Moderator - if this is cluttering the forum too much, please move to the alternate 'fly away' thread.


There is a yaw gyro for driving the tail rotor FET, but that's it. Pitch and Roll stabilization is done via the fly bar tilting the rotor head to affect blade pitch (one increases pitch the other decreases pitch), mechanical stabilization.

Your situation sounds like some kind of interference. The fact that servos and tail rotor came back into operation (even though you didn't have control) seems different from the other accounts where the heli starts pirouetting and just climbs and climbs and climbs until its either lost, or hits something.