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Mikado Modellhubschrauber . GrandRC . CanoMod

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Aerial Photography and Video > First HC flight ... could do with some input please!
 
 
nooobs
Key Veteran
Location: Toronto, Canada

By moving it in the front, inside the canopy, you will no longer have use of position hold as the "lens" is blocked. Personally, I don't think you need to play with the position hold. It's only good for very low level position hold.
06-27-2008 09:00 AM
HOMEPAGE  
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

I'm sorry if this has been repeated but I'm confused as to what settings the horizontal mode uses to keep the heli level. Are these the settings calibrated by the autotrim or set button procedure?

I converted my Logo 600 to the flybarless head this morning using HC's rigid mode. I initially hovered for 10 seconds, landed and pressed the set button... all good. I then hovered for another 10 seconds and clicked the autotrim and found the heli then started drifting backwards with sticks centred.

Horizontal mode also seemed to be a little unpredictable. I first increased the hoz mode gain and the heli hovered beautifully. I then reduced the gains and did a few circuits, hovered again and applied hoz gain upon which the heli started drifting rapidly backwards.

I'm a little confused as to how the HC learns it's horizontal mode settings and how it maintains settings for a level hover. Perhaps I'm doing something wrong but it was so much easier to get a solid hover using the Spartan AP2000i.
06-28-2008 06:16 AM
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Anyone???

I've tried emailing Helicommand but have had no response.
06-30-2008 04:33 AM
 
 
rroback
Key Veteran
Location: Irvine (UCI), Ca

You're doing the correct procedure. Basically, you do the trim-push the set button to give the HC unit a gross ideal on the null (i.e. horizontal) trims. Let me use a numerical example, as I'm having a lot of trouble using words. The HC unit uses an accelerometer ( a few) to measure changes in angle. Let say 0 is the proper value indicating the unit is perfectly level. You mount the unit imperfectly, and the sensor now reads 257. You do the initial trim , and say hey, 257 is what the actual null value should be. The unit saves that. Then, you switch cameras, and say well, now my cg is off. You hover, and autotrim, and say, Look, 257 was the true value, but now you're reading 290, so use enough cyclic compensation to keep it at 257.

Does that make sense? Horizontal hold is dependent on how well your heli is cged, and how well you autotrimmed. That is the same for the small units, as well as the Profi. If you need more detail, ask away.

Also. a little note for engineers out there. I understand the details of accelerometers ( and the ideas of magnitude and direction for different vectors), and how everything is based on the gravity vector, so forgive me if I left out a few details. It was for simplicity.

Rhett... I can't fly, luckily the HC Profi Can!
06-30-2008 04:46 AM
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Thanks Rhett, yes that makes sense .

Forgive me but I'm still a little confused as to why the autotrim I set for a perfect hover at the biginning of a flight then changes after doing a few circuits and figure 8's.
06-30-2008 07:48 AM
 
 
rroback
Key Veteran
Location: Irvine (UCI), Ca

That I can't help you. Once it is autotrimmed, it should be good to go, unless you change cg. I'm assuming the unit is secured very tightly?

Rhett... I can't fly, luckily the HC Profi Can!
06-30-2008 07:58 AM
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Yes everything's rock solid. No movement in the payload or HC unit whatsoever.

It's like the unit is constantly trying to learn centre stick.
06-30-2008 08:08 AM
 
 
rroback
Key Veteran
Location: Irvine (UCI), Ca

So you trim, it hovers great, you fly around, and it's out of trim? Could be a dumb question but, nothing is causing the unit to auto-trim in flight ( i.e. incorrect tx. mixing?)?

Rhett... I can't fly, luckily the HC Profi Can!
06-30-2008 08:11 AM
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

That's correct.

I initialy suspected the same thing so I checked the software diagnose tab and the autotrim slider seems to be functioning normally. No TX mixes to mess things up.

I don't touch the TX trims either so I know it's not that.
06-30-2008 08:14 AM
 
 
Ben H
Senior Heliman
Location: South / South West , UK

David,

How are you finding the HC compared to the AP2000i?

I'm using AP2000 on my trex and Maxi joker but my biggest issue is having to re-trim when I yaw.

Is the helicommand any better in this respect? I imagine if your using the autotrim function then you would have to re trim when you yaw round to a different heading, much like the AP2000.

And if you manual trim then I guess you'd drift downwind excessively (like calibrating the AP2000 on the ground)

Is there any distinct advantage to changing over as far as changing heading is concerned?

Ben.... "what goes up, must come down!"
08-25-2008 10:30 AM
HOMEPAGE  
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Ben,

I assume you are refering to yawing the heli in a breeze?

Both the AP2000i and the HC will require retrim for a stable hover through yaw in a breeze. Of course neither unit should require retrim in zero wind conditions, unless the horizon isn't level (ie mountains, built up areas, etc) in which case the AP2000i would require slight retrim as the IR sensor pans around the uneven horizon line.

GPS would be required to keep the heli in a stationary hover in a breeze and neither unit has this feature. Some might argue that the HC has "ground mapping technology". IMHO this technology is useless at any altitude above 3-4 feet and should not be considered as a real advantage over the AP2000i.

I have actually found the stabilser trim on the AP2000i to be more reliable than the HC so long as you know it's limitations and fly within them. The HC gyro's seem to drift during flight and I often find it difficult to rely on them to really lock that hover in at altitude.

Having said that both units have their pros and cons. I much prefer the HC over the AP2000i for video work.

Just my 2c.
Griffo
08-25-2008 10:51 AM
 
 
nooobs
Key Veteran
Location: Toronto, Canada

Quote 
Some might argue that the HC has "ground mapping technology". IMHO this technology is useless at any altitude above 3-4 feet and should not be considered as a tool for AP.


Just by saying "HC" is inaccurate. HC 3A/3D/Rigid is what you're referring to. HC Profi has a better position hold at a higher altitude.

As Griffo mentioned both units, AP2000i and HC 3A/3D/Rigid have limitations. AP2000i relies on IR sources. HC does not. IMO you have a wider range of flying conditions with the HC.
08-25-2008 11:02 AM
HOMEPAGE  
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Ah yes thanks for the correction Noobs. I was refering to the 3A/3D/Rigid. I think the profi comes in at a completely different price bracket and therefore not really comparable to the AP2000i.

I just found that when used correctly the AP2000i was able to provide a far better locked in hover and I never had to worry about drifting gyros. That said the AP2000i did have a number of cons, the biggest being the limitation of the IR signature. On an overcast day it wasn't nearly as accurate as on a sunny day. One also had to consider the position of the sun late in the day as it approched the horizon.

I'm running the Rigid and while it's brilliant in certain conditions I'm just not all that amped about the stabilisation ability in comparison to my old AP2000i.
08-25-2008 11:20 AM
 
 
Ben H
Senior Heliman
Location: South / South West , UK

thanks for the input

So really there is little advantage to make it worth spending out on 2 x helicommands over the AP2000's

I find that the AP is very accurate in all types of weather, overcast, low sun, and water. As long as you get in position, hold the calibrate button for 1 sec then fine tune with trims. If the sun is low or wind is high then the AP2000 will allow for this in the calibration and be very accurate, but you cant use much rudder without turning off the AP, moving position then re-setting.

I guess this procedure isn't that different to the auto trim setup on HC??

Ben.... "what goes up, must come down!"
08-25-2008 12:25 PM
HOMEPAGE  
 
 
rerazor
Elite Veteran
Location: Mich.

Well I guess I'm bias or something. The HC units are way better then the APi. With the HC units it makes no difference your environment, ever. You can yaw and it does not change its last setting (unlike the IR the APi uses).

I suggest if your HC's gyros are drifting that you reset all trims in the software and redo the SET button procedure. That brings it back in line. I tend to do that every 10-20 flights to safe.
08-25-2008 12:59 PM
 
 
Ben H
Senior Heliman
Location: South / South West , UK

Rerazor,

I really like the idea of being able to yaw without re-trimming, are you saying that the HC will keep it's attitude whatever it's yaw position?
Alot of HC users say they are using the autotrim each time (i guess to counteract the wind) and therefore have to re-trim for a different prevailing wind direction. I assume you use the SET button procedure and either fly in no wind or accept the downwind drift?

Ben.... "what goes up, must come down!"
08-25-2008 01:21 PM
HOMEPAGE  
 
 
rerazor
Elite Veteran
Location: Mich.

I auto trim for the wind or change in CG. The HC will drift (on a flat level plane) if its windy or from momentum. I spent more time with the APi messing with trimming etc.. then flying. With the HC unit I might have to auto trim but I find it way more reliable the the Api.
08-25-2008 01:30 PM
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Hmm, maybe we're flying in different environments, or maybe my HC just needs a little more tweaking . I just found the AP2000i to have a more reliable attitude hold in the environments and conditions I fly in.

I'm certainly not pushing either product as having used both I can see each has it's pros and cons.
08-25-2008 01:41 PM
 
 
Ben H
Senior Heliman
Location: South / South West , UK

So if you auto trim for the wind, the 8 sec hover will be tilted into the wind (pitch & roll) to keep it in one place right?
So it will keep leaning into wind (starboard for example) hands off. now if you yaw 180 degrees the heli must still be leaning to starboard but now with the wind coming from port side. My point is surely you have to re-autotrim after yawing much like the APi, or can you get away with not trimming as much as you do with the APi. The less time I have to muck about with calibration, autotrim, trimming etc on a flight is more time spent concentrating on better photo angles

Ben.... "what goes up, must come down!"
08-25-2008 02:00 PM
HOMEPAGE  
 
 
Griffo
Senior Heliman
Location: Canberra, Australia

Ben, you are correct. Both units have to be re-trimmed in order to change the helis attitude to allow for wind.

If I remember correctly the AP2000i does this in around half a second by reading the helis attitude in relation to the horizon as the calibration switch is activated. The HC units require the heli to be in a stationary hover to learn the correct position before flicking the calibration so I assume the gyros take an average of the heli's attitude over the 8 second period. Different methods for a similar outcome.

The sole purpose of each unit is to keep the heli level with the horizon. Wind will still affect them in the same way through different orientations. However, it's important to note that if you are flying in an area with hills or next to a mountain you will find you also have to retrim the AP2000 to allow for the change in horizon level, but then you'll be doing that for the wind anyway .

As far as I'm aware, GPS positioning is the only thing that will allow the heli to remain stationary in the wind (zero drift) without having to repeat the calibration procedure. I believe this will be available as an add-on to the Profi but it has yet to be released. Carvec offers the same thing... Very nice bit of hardware that will give you time to kick back and have a cuppa while you decide which angle suits best .

Griffo
08-25-2008 02:25 PM
 
 
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Aerial Photography and Video > First HC flight ... could do with some input please!
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