AR6335 on a T-rex 250 Pro DFC

[qntt]

It weighs 2g! It is very tempting if it's possible. Anybody tried it yet?

I have to tell you it works exceptionally well on my 180 CFX.

[pgoelz]

It doesn't look like the stabilization system understands 120 degree CCPM mixing so I doubt it would work in anything other than a straight 90 degree swash setup.

Paul

[qntt]

Originally Posted by pgoelz

It doesn't look like the stabilization system understands 120 degree CCPM mixing so I doubt it would work in anything other than a straight 90 degree swash setup.

Paul

It is used in the 180 CFX -- 120 degree CCPM mixing...

[pgoelz]

Originally Posted by qntt

It is used in the 180 CFX -- 120 degree CCPM mixing...

From the 180CFX page:

Spektrum™ DSMX® AR6335 nanolite receiver with AS3X flybarless technology

I read through the AR6335 programming manual and there is no mention of "AS3X flybarless technology" so perhaps the AR6335 in the 180 uses different firmware? Really cool if it was standard (but un-documented).

I am using a BeastX clone in my 250 but using the AR6335 would save quite a bit of weight. Plus, I prefer the way Eflite flybarless works. The BeastX and clones use rate mode gyros and I have to hold a small amount of forward cyclic in forward flight. Eflite stabilization is heading hold, so after forward flight is established, no continued forward cyclic from the transmitter is required.

Paul

[qntt]

Originally Posted by pgoelz

I read through the AR6335 programming manual and there is no mention of "AS3X flybarless technology" so perhaps the AR6335 in the 180 uses different firmware? Really cool if it was standard (but un-documented).

Paul

My thoughts exactly!

[pgoelz]

Hmmmm.... I still own and (occasionally) fly my old Ikarus Piccolo. It uses a 90 degree swash, so the AR6335 would be a drop in fit and include heading hold stabilization. If I could adapt the Eflite servos to it instead of the HS50s it currently uses, the combined weight savings would be huge. Thinking......

Paul

[qntt]

Something tells me the price for crimping tools will go up in the near future with all the guys wanting to change servo connectors to pico blade.

[vtown nick]

The 3gx mrs is 1 servo 90 degrees setup so why not try this? Only issue is that blade mounts the elevator servo in the front and align in the back. I don't think you can change gyro direction compensation in this FBL?

[pgoelz]

If anyone wants to try a 3GX MRS, I have one I'll sell. You might be able to flip the device around end for end and /or top for bottom to get the corrections going in the right direction. Note that it is correct as-is for the Trex 250.

I have to say though that the reason my MRS is not being used is because the gyros have stability / drift issues. It likes to tilt in random directions after successful initialization. Sometimes this is subtle and sometimes not so subtle. Sometimes it goes away during the flight and sometimes it gets worse.

Paul

[skunkworx]

Originally Posted by pgoelz

. . . I prefer the way Eflite flybarless works. The BeastX and clones use rate mode gyros and I have to hold a small amount of forward cyclic in forward flight. Eflite stabilization is heading hold, so after forward flight is established, no continued forward cyclic from the transmitter is required.

This is an interesting observation. Is this a documented difference? The AR7200 shouldn't need further input unless you have the pitching-up compensation set incorrectly.

[pgoelz]

Originally Posted by skunkworx

This is an interesting observation. Is this a documented difference? The AR7200 shouldn't need further input unless you have the pitching-up compensation set incorrectly.

I fly the Blade 130X and MCPx. Both have heading hold gryo action on the cyclic once you raise the throttle. You can, for example, balance them on a skid on the ground and they will remain there for quite a while until the gyros drift enough to move them away from that attitude. Lean it forward into forward flight and it will hold that attitude in spite of any aerodynamic pitch up tendencies.

I also fly a couple BeastX clones (the separate controller, not the controller with integral receiver) with V2 and V3 firmware. The cyclic gyros in those units are in rate mode full time. If you lean it over on a skid, the swash will slowly return to level in a few seconds. It isn't noticeable in normal manuvering, but it is noticeable in fast forward flight since it wants to return to a level swash instead of holding the attitude you last commanded. It resists movement and therefore reduces the normal aerodynamic / gyroscopic pitch up tendencies of a flybarless rotor system but it does NOT hold a commanded attitude indefinitely.

Paul

[mba83]

Just de-case the AR7200 if you want to save weight. Much less work and cheaper than changing connectors, learning a new FBL unit, etc. I am using a de-cased IKON, and it's very light for the 250.

[qntt]

Originally Posted by mba83

Just de-case the AR7200 if you want to save weight. Much less work and cheaper than changing connectors, learning a new FBL unit, etc. I am using a de-cased IKON, and it's very light for the 250.

Nowhere near 2g.

[bmc76]

180 uses different firmware wich isn't available yet to flash airplane rx's to work on a heli. It is 120 swash, you set all fbl units to 1 servo 90 in the tx, at least every one I've ever used. The fbl controller handles all mixing.
There doesn't appear to be a tail setup menu though and no way to adjust cyclic pitch on the 180, you can use the pitch channel to adjust collective.

Unless you pull the rx right out of a 180 you aren't going to have any joy getting it to work on a 250.

[skunkworx]

Some types of FBL units do use radio mixing. The old 3G systems used 120 degree CCPM from the radio in order to control the helicopter. Most systems tend to use the one servo or MCCPM mixing, and servos are controlled directly through the gyro unit, they would just take 'different' steps to set it up if you've never worked on an FB heli before.

[qntt]

Originally Posted by bmc76

180 uses different firmware wich isn't available yet to flash airplane rx's to work on a heli. It is 120 swash, you set all fbl units to 1 servo 90 in the tx, at least every one I've ever used. The fbl controller handles all mixing.
There doesn't appear to be a tail setup menu though and no way to adjust cyclic pitch on the 180, you can use the pitch channel to adjust collective.

Unless you pull the rx right out of a 180 you aren't going to have any joy getting it to work on a 250.

I hope very soon we will have the firmware if not you can buy the unit as a replacement part for the 180.
There is a cable from spektrum to update the firmware and an cable for an app but it works only for planckers. I suspect they don't want us to use the unit on the 250 since it is obvious they directly compete so maybe the fact that you can't adjust some things is intentional.
Well, we are an resourceful bunch and we will find a way. The promise of a 2 g fbl in a 250 is very tempting.

Correction: They absolutely have to release a new firmware to resolve the tail kick problem and the save settings problem and then what's stopping us from flashing that firmware onto a normal airplane receiver?

[skunkworx]

Originally Posted by qntt

Well, we are an resourceful bunch and we will find a way. The promise of a 2 g fbl in a 250 is very tempting.

I think stuff like this will be a driving force in keeping helis current. Quads have added a lot of newer people who need this type of technology, so the added benefit is eventually we'll start seeing more and more of these around, just with less proprietary or more open source than the Eflite stuff. I don't doubt that they are keeping a lid on it as long as they can and I can't really blame them, but I agree it would be nice to have a really good, light gyro for these smaller machines, but I'm pretty happy with my AR7200BX in my 250 even though it's a weight penalty.

[qntt]

Originally Posted by skunkworx

I'm pretty happy with my AR7200BX in my 250 even though it's a weight penalty.

I use the same thing (AR7200BX) and it is so heavy that pyro comp doesn't keep up with the offcenter mass. It wobbles. That's why I want something light mounted inside the heli.

[myxiplx]

In all honesty, while its light at 2g, the firmware is going to be totally tuned for the 180, I think its unlikely it will ever fly as well as a proper tunable FBL unit.

If you want something lightweight, there are plenty of modern units that are in the 5g range when de-cased.

And you can also get a 250 under 300g without doing that, and while using stock servos.

There's no need for this in my opinion, there are already better solutions out there.

[jadewarrior]

Originally Posted by skunkworx

This is an interesting observation. Is this a documented difference? The AR7200 shouldn't need further input unless you have the pitching-up compensation set incorrectly.

It doesn't. I have three AR7200BX equipped helis and they all fly great. Set an attitude and forget it. It holds just fine. If it doesn't, then you most likely have vibe issues.