Vortex Bail Out

[waveydavey]

Anyone know where they are with this. I've looked on their site and HF but can find only bits and pieces. I'd heard there was beta firmware but don't seem to be able to find any info

[tomatwalden]

The only beta firmware out at the moment is the V4 with e-gov. No hint of a "rescue function" that I'm aware of. Bearing in mind that the term "bail out" to many/most means auto-rotation bailout ... ?

eGov interim firmware - HeliFreak

[myxiplx]

Heya,

From what I've read on HF from Angelos' posts, it's something Angelos is looking at, but there's no ETA or anything like that. I believe Angelos and his beta team have done some testing of it, but my guess it that it could be a while before it's released, Angelos is only one chap and he doesn't like to release things until they're solid.

What there is out now is an interim firmware release for the electric governor with soft start and autorotation bailout. It's basically the current release plus the eGov feature. I'm running that now on my Gaui X3 and loving it, it's working very nicely.

[myxiplx]

Found the thread, complete with a video from Angelos:
Bail out - HeliFreak

[jimmyhorns]

Last time I spoke with Angelos (about a month ago, maybe longer), its something that is in the possible pipeline, but no timescale at present as there are a number of things that need to be worked through before even a beta is possible.

A reasonable amount of processor time is required to have the FBL unit actually know where you are relative to the ground, so its pretty complex stuff...

[tomatwalden]

Not to mention, a busy CPU = more current draw, and more heat ...

[waveydavey]

The thread on HF appeared to highlight the fact that the only unit that could support this at the moment is the VX1e because of the type of sensors.

The interim E gov seemed to work okay for me for the record

[waveydavey]

Does the unit really need to know where you are relative to the floor, surely if upright collective and levelling would be enough and inverted the same. Knife edge then go the quickest way to upright and add collective, I know I've simplified it but isn't that all there is to it.

[jimmyhorns]

Does the unit really need to know where you are relative to the floor, surely if upright collective and levelling would be enough and inverted the same. Knife edge then go the quickest way to upright and add collective, I know I've simplified it but isn't that all there is to it.

Working it through in my head im guessing there is a bit more to it, and I think it would have to know where the horison is from the chat. It has to know where the heli's disk is relative to the horison, and know in which direction its moving, and then work out the quickest way to get back to a flat disk, and then which direction to apply collective in.

If it didnt know where it was relative to the ground or horison, how would it know how to correct?... you cannot just use a snap measure of gravity, as that will depend on what acceleration the heli is under when you hit the switch...

[tomatwalden]

Does the unit really need to know where you are relative to the floor, surely if upright collective and levelling would be enough and inverted the same. Knife edge then go the quickest way to upright and add collective, I know I've simplified it but isn't that all there is to it.

How does the unit know it's upright? As far as I know, the MEMS sensors only tell the FBL unit what movement the heli is subject to. I suppose if you assume flat/upright at the start, you could theoretically record every movement (pilot induced or otherwise) and thereby know where the heli was in space, but realistically I guess errors would creep in fairly quickly ...

I'm not sure how Neo or BD work this out to be honest .. ??

EDIT : Just found this post about the Bavarian Demon (HC3SX) ... The following paragraph seems to imply that the BD uses dead reckoning (the recording every movement I mention above).

"Only one time did I have an issue, and I only had myself to blame. I hit the rescue switch at the beginning of a flight, and the Goblin shot up and to the side at a 45 degree angle. Remember I said it needed to be kept still during initialization? Well this is what happens when you don’t. I later learned that the gyro is constantly calculating the horizon and that if I had let the helicopter hover for a few seconds it would have adapted, and gotten over the fact that I didn’t exactly keep it still when I plugged it in." .... http://www.rcgroups.com/forums/showthread.php?t=1761516

[tomatwalden]

The thread on HF appeared to highlight the fact that the only unit that could support this at the moment is the VX1e because of the type of sensors.

...

Funny thing is though, I think the difference with the VX1e is that it has accelerometers (MEMS Gyro-Accel | Gyroscope | Accelerometer | Processing - MPU-6000/6050). But the BD-3SX makes a big deal about the fact it doesn't rely on (vibration sensitive) accelerometers ...

[waveydavey]

I don't know I ain't no physicist boys I'm going along with good old Daves logic which is how does the bubble in a spirit level know it's level, if theres an electronic way to record where the hypothetical bubble is then you would know where the heli is IE level in both X and Y axes, doesn't matter a fanny about Z. I get that it wouldn't know where it is height wise but as long as it's not cutting daisies surely thats all you need a calibrated electronic bubble The difference between the calibrated level and where you are is the angle you're at. Theres more to it than that obviously, trajectory, speed etc I know that

More thinking, which isn't good for me. When you switch on and your unit initialises the swash will jump level IE the reference is taken from something it's only when you start moving the heli that the swash will start moving about. So relatively the unit doesn't care about where it is in space as long as it's not upside down or on it's side. Even then I think it would set square to the mainshaft which is where it needs to be in order to climb to safety with collective added

[tomatwalden]

I don't know I ain't no physicist boys I'm going along with good old Daves logic which is how does the bubble in a spirit level know it's level, if theres an electronic way to record where the hypothetical bubble is ...

The bubble doesn't "know" - rather it's simply gravity pulling the heavier liquid towards the earth. There are ways to mimic the spirit level electronically, but they're complex. Wikipedia has a breakdown here : Attitude control - Wikipedia, the free encyclopedia

The interesting thing is that the sensors are broken down into two fundamental types - relative and absolute. The MEMS sensors in FBL units are relative. A spirit level is absolute. The difficultly is how you mimic an absolute sensor with a relative one. Dead reckoning (ie. tracking from a known good point - eg. take off) seems to be the method that the BD3SX uses, but as James mentioned, the constant calculations to achieve that are difficult and CPU intensive ...

Then again, I could be completely wrong about all this! But no FBL manufacturer seems keen to discuss their actual methods for achieving bailout. Except I do seem to remember an early helicommand unit that used thermal sensors to detect the earth's horizon ... (edit: Bavarian Demon Rigid V2)

[waveydavey]

But surely the 2nd part of my musings where the unit is calibrated against the squareness of the mainshaft IE setup gives the absolute setting, everything after that is relative.

[tomatwalden]

But surely the 2nd part of my musings where the unit is calibrated against the squareness of the mainshaft IE setup gives the absolute setting, everything after that is relative.

Well yes, that's the "dead reckoning" method. From the start of the flight, you have known good fixed point. But as soon as the heli takes off, you have to track every movement from that point. That movement could be affected by wind, gravity, aerodynamics, etc. etc. The MEMS sensors will pick up those movements, but the the FBL unit will have to constantly track how that movement affects the heli ... Cumulative errors in the calculations will creep in, although maybe our flights are short enough for those errors not to get too bad? The point is though that tracking those relative movements in 3D space is complex!