WKM, S900 (7kg), gaining altitude on yaw in atti, & GPS stop.

S

ShackFlyer

Member
Hi there,

Just wondering what FW version & gains people are using, if they get chance to look.
I'm getting a lot of altitude gain on yaw when flying a square (in atti) & turning on the spot at the corners.
Also in GPS when I stop to hover it's doing it as well esp nose/tail into a headwind.
Mines v 5.26. with default S90o suggested gains (new aircraft), although upped altitude gain to 120 from(100), but think it's made it worse.

Any advice welcomed
Thanks
Mike
 


S

ShackFlyer

Member
Hi & thanks Ben.

3-5 metres altitude gain, certainly more than the 2m envelope. It hovers fine, rock solid but as soon as you put any rudder input in, even very gently it's like lifting the throttle at take off.
It's also losing a good couple of metres in initial forward flight.
It seems a lot more than my Naza mv2 on 4kg tarot 680, & the Align APS-M which is on rails by comparison.

Does IMU mounting tape thickness/softness (damping vibration as per DJI faq) make much difference in your experience? (stock mounting position BTW)
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Okay, that is quite a huge amount!

I think it's more fundamental than vibration. I'd double check my IMU/GPS positions on the assistant program.

Maybe have a look at your transmitter and check for an errant mix that may be causing it (something like rudder>throttle).

Recalibrate your transmitter in the assistant also.

Whilst in the assistant program watch what happens when you give a rudder command to see if the throttle increases.

Hmmm, I'm sure there's more but that's it for now.

What transmitter are you using?
 

S

ShackFlyer

Member
Gps position spot on CoG & measuremnt correct.
IMU in stock position but do you measure to centre of case or front & bottom or top of it?.


Radio is Futaba 14SG with no mixes, only switchable expo levels & end points on elev, rudder & aileron to fly slowly for smooth video. No errant mixing.

Everything looks fine in asst.

I've seen mention of people rolling back to v5.20 & solving similar issues (google & search on here).

Are you using IMU v1 or 2? & which FW version?
 



S

ShackFlyer

Member
Cheers.
Had a look & adjusted IMU position in asst slightly (measured to centre of its box as per dji faq) trouble is its 3cm tall & asst only does full cm's.

Do you find IMU v2 flies any different to the v1 I have been supplied with this brand new WKM? Does it only make a difference to over 7kg rigs?
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
I'm not sure. I've been flying the IMU V2 for around 18 months so can't really remember if there was a big difference. I think mine had symptoms similar to yours (in fast forward flight it would lose height) hence why I added the V2 back in the day. All good now!

The hole on the side of the IMU is where the baro sensor is. On IMU V2 it has two holes to prevent 'static pressure build up' apparently. This was the cause of poor altitude hold in the past.

Check the hole isn't covered and try to keep it out of air flow. Although it should be fine in the default position.

Just keep playing around with it. You could always ask your supplier for a replacement otherwise.
 

S

ShackFlyer

Member
Ok cheers.
I'll ring Heliguy on Monday & chat to their tech's.
I don't really want to swap it as just submitted amended Ops to EuroUSC changing aircraft & don't want the beggars charging me another £114 to review it again!
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Ignore EuroUSC. The CAA doesn't require most of the things that they ask. All the CAA want is someone to certify pilot competency, and that's it.

I'd go for the IMU V2 personally. It's nice and heavy so less prone to vibration.

Cool? ;)
 

S

ShackFlyer

Member
Thanks for the info Ben.

Had 2 perfect flights this morning. Only changes I made were thicker/softer gyro tape under IMU, & 1cm vertical change of IMU in asst.

Either that or it was my frozen thumbs ;-)
 

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