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3GX Conversion Experience
The urge to try something new finally overcame the restraints around my wallet and I decided to convert my Trex 250SE to a new fangled Flybarless machine, having picked up so much useful info from this forum I thought I would share my experience, maybe it will help someone else like me.
To put my comments and experience into context; I've been flying proper heli's since around March this year so still consider myself a beginner, I can hover nose-in, fly figure of eights and I'm slowly getting to grips with flying around in full on banked circles. I'm a long way off this crazy upside down stuff and tend to focus on ensuring the heli does exactly what I want it to do. In short I'm a long way away from appreciating any performance differences between the 3GX, BeastX or any of the other FBL systems. My FlyBarred 250 was flying perfectly well with a rock solid tail and my motivation to change over to FBL was really driven by the desire to learn something new and see how much of difference throwing away the flybar would make.
With some absolute bargains available on brand new 3GX units (new from £80!), I went down this route even though the BeastX seems to be the more popular choice. I also went with the Align DFC head which again at £30 was another easy decision to make.
Assembly
I mounted the 3GX unit to the underside of the Gyro plate as putting it there provide full and easy access to the button, pots and lights. The Spektrum AR6100e receiver was going to go on the top of the Gyro plate but I struggled to make it fit without snagging on the tail servo, I gave up and borrowed a satellite from another heli instead for a much cleaner job. I later discovered that this is not a ideal solution if you use a DX6i as you loose the ability to set the Gyro gain and are stuck with rate mode only. I couldn't find away around this and reverted back to the AR6100e this time mounted on the side frame, opposite the ESC, doesn't look as pretty but works fine.
Set Up
I used some uTube set up videos (look for "Freddy Can Fly") and the notes posted on here by Trex-Deanoo, my thanks to both as they makes the set up process pretty simple to follow. I went with the default software settings and gingerly went for the first flight, boy was that fun! The 250 is pretty twitchy bird at the best of times but I had tamed it, my first FBL flight was like going back to my first attempt at hovering with the controls hugely sensitive and chronic over corrections on my part. I managed to land in one piece and messed about with the D/R ad Expo setting but they made little difference.
After a little research on here I found some set up files posted by TourerJim and spent a couple of hours mapping the values in the txt files to the parameters in the 3GX software and trying to understand what they mean. The second flight with the TourerJim settings was an improvement, I could at least hover but nowhere near as well as I could before and the heli was still pretty unstable.
I went back over my mechanical set up having borrowed a digital pitch gauge from friend at the field, I originally tried setting up the heli using my old school mechanical gauge and a flat reference piece held in place on top of the head button, not the best option. I found that my mechanical set up whilst good enough for me to fly with the FB was nowhere near good enough with the FBL unit, I think the key problem was a big mismatch in the cyclic pitch +ve to -ve. I don't think I ever really looked at this before and my brain simple compensated for the different responses while flying, the FBL unit isn't that clever and seems to needs a spot on set up. I bought myself a swash plate levelling tool and went back over the heli eventually getting it spot on.
The next flight was a huge improvement, my heli was stable again but still extremely sensitive. I backed way off on the Elevator/Aileron flip rates (10/5) and added a little cyclic exp and with the dual rates in the radio dialled down to around 50% I have a heli I can fly again, as my confidence grows I'll up the rates.
Was it Worth it?
Need a little more time to get comfortable and fine tune the settings but I think so. The heli seems to bounce around less in the wind and feels a little more planted as I fly around.
I also had hours of fun figuring out how the 3GX works: the stick movement doesn't map 1 to 1 to the swash plate any more, it maps to a roll rate that the swash plate attempts to achieve, the set up process essentially calibrates the 3GX to the swash (at least that's how I understand it).
My heli looks better without the flybar.
I'm looking forward to the fine tuning and will no doubt follow the same path with my TREX 500 in the not to distant future.
Some key takeaways for anyone else looking to do the same thing:
To put my comments and experience into context; I've been flying proper heli's since around March this year so still consider myself a beginner, I can hover nose-in, fly figure of eights and I'm slowly getting to grips with flying around in full on banked circles. I'm a long way off this crazy upside down stuff and tend to focus on ensuring the heli does exactly what I want it to do. In short I'm a long way away from appreciating any performance differences between the 3GX, BeastX or any of the other FBL systems. My FlyBarred 250 was flying perfectly well with a rock solid tail and my motivation to change over to FBL was really driven by the desire to learn something new and see how much of difference throwing away the flybar would make.
With some absolute bargains available on brand new 3GX units (new from £80!), I went down this route even though the BeastX seems to be the more popular choice. I also went with the Align DFC head which again at £30 was another easy decision to make.
Assembly
I mounted the 3GX unit to the underside of the Gyro plate as putting it there provide full and easy access to the button, pots and lights. The Spektrum AR6100e receiver was going to go on the top of the Gyro plate but I struggled to make it fit without snagging on the tail servo, I gave up and borrowed a satellite from another heli instead for a much cleaner job. I later discovered that this is not a ideal solution if you use a DX6i as you loose the ability to set the Gyro gain and are stuck with rate mode only. I couldn't find away around this and reverted back to the AR6100e this time mounted on the side frame, opposite the ESC, doesn't look as pretty but works fine.
Set Up
I used some uTube set up videos (look for "Freddy Can Fly") and the notes posted on here by Trex-Deanoo, my thanks to both as they makes the set up process pretty simple to follow. I went with the default software settings and gingerly went for the first flight, boy was that fun! The 250 is pretty twitchy bird at the best of times but I had tamed it, my first FBL flight was like going back to my first attempt at hovering with the controls hugely sensitive and chronic over corrections on my part. I managed to land in one piece and messed about with the D/R ad Expo setting but they made little difference.
After a little research on here I found some set up files posted by TourerJim and spent a couple of hours mapping the values in the txt files to the parameters in the 3GX software and trying to understand what they mean. The second flight with the TourerJim settings was an improvement, I could at least hover but nowhere near as well as I could before and the heli was still pretty unstable.
I went back over my mechanical set up having borrowed a digital pitch gauge from friend at the field, I originally tried setting up the heli using my old school mechanical gauge and a flat reference piece held in place on top of the head button, not the best option. I found that my mechanical set up whilst good enough for me to fly with the FB was nowhere near good enough with the FBL unit, I think the key problem was a big mismatch in the cyclic pitch +ve to -ve. I don't think I ever really looked at this before and my brain simple compensated for the different responses while flying, the FBL unit isn't that clever and seems to needs a spot on set up. I bought myself a swash plate levelling tool and went back over the heli eventually getting it spot on.
The next flight was a huge improvement, my heli was stable again but still extremely sensitive. I backed way off on the Elevator/Aileron flip rates (10/5) and added a little cyclic exp and with the dual rates in the radio dialled down to around 50% I have a heli I can fly again, as my confidence grows I'll up the rates.
Was it Worth it?
Need a little more time to get comfortable and fine tune the settings but I think so. The heli seems to bounce around less in the wind and feels a little more planted as I fly around.
I also had hours of fun figuring out how the 3GX works: the stick movement doesn't map 1 to 1 to the swash plate any more, it maps to a roll rate that the swash plate attempts to achieve, the set up process essentially calibrates the 3GX to the swash (at least that's how I understand it).
My heli looks better without the flybar.
I'm looking forward to the fine tuning and will no doubt follow the same path with my TREX 500 in the not to distant future.
Some key takeaways for anyone else looking to do the same thing:
Get a digital Pitch Gauge
Get a swash levelling tool
Get your mechanical set up spot on (50% Collective = 0 Pitch, at zero pitch extremes of both Elevator and aileron = 8 degrees)
Understand how the FBL unit works and what it does
For £80 the 3GX FBL unit is an absolute bargain
Get a swash levelling tool
Get your mechanical set up spot on (50% Collective = 0 Pitch, at zero pitch extremes of both Elevator and aileron = 8 degrees)
Understand how the FBL unit works and what it does
For £80 the 3GX FBL unit is an absolute bargain
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