Any tricopter experts here - trimming problem :)

[Efliernz]

I've been flying KK boards on a (500mm / 20") armed tri for 6 months now. I have several boards - all I find go out of pitch trim after I have looped my tri (or pulled up hard). I need approx 1/3 fwd stick to keep it level afterwards until I power-cycle the board.

I swapped to a Paris V3.0 board for a test this morning and the tri has the same pitch trim problem. The tri flies really nice until I over-bank it. I also have a new Flycam Blackboard (Minsoo Kim) I'm trialing that is the same.

I know I'm pushing the tri but surely I'm not the only one having these trim-change problems? Am I? Any ideas?

Pete

 

[Crash]

Is it possible that the G forces are tweaking your airframe? Possibly the rear motor mount.

I'm just guessing. Keep us informed when you find the problem.

 

[Efliernz]

Thanks.
I'm about to build 3 new machines for club members so I'll be trying to tighten-up a few things. I'm going to drop length to 450 too.

The distance it goes "out" seams too far far a mechanical movement. Oh I don't know... I have one more option - I have a CC board as of the weekend so Time I watched the videos and learnt how to deal with this board.

Pete

 

[matwelli]

that will be a good comparison,talk to me before using the CC board, you have a development one, and needs a setting changed to fly properly

 

[Crash]

Thanks.
I'm about to build 3 new machines for club members so I'll be trying to tighten-up a few things. I'm going to drop length to 450 too.

The distance it goes "out" seams too far far a mechanical movement. Oh I don't know... I have one more option - I have a CC board as of the weekend so Time I watched the videos and learnt how to deal with this board.

Pete

Pete,

It's open source stuff that you are using. Tell your club friends to DIY or help them build. After all, 'getting there' should be half the fun. Right?

I do agree that it does seem 'too far'. However with the same behavior on several different boards, that's the only thing I can think of to cause the problem...

Oh wait: Maybe the ESC on the tail is overheating or the ESC thinks that the voltage has dropped before the others.

What motors and ESCs do you use?

 

[Efliernz]

I'm using the DT750 motors / 10x3.8 props and HK Simple 45A (yes 45A) esc's. I rarely exceed 30A (all up) with hover down at 15A. Basically... it's idling
I have calibrated the esc's.

Here is it idling around 30 minutes ago. Not a bad mid winter day...

As for the club builds. I'm doing instructions and a "short kit" and a support workshop. Components that work and the wood and CF cut to size. Two of them already own helis and have flown my tri - and they love it. It is a very smooth machine.

I'll just behave for a while.

Pete

 

[SpeedfreakNZ]

Thats interesting, I am new to Multi's and Gyros in general and I have had the same problem with my KK board quad. Now that I am getting a little cocky flying the thing, if I do a loop or even a hard turn the board loses its lock and I have to hold a stick or sticks over to hover, I thought it was my setup

matt, did you get that message about the props, I need another two sets urgently

 

[matwelli]

yea, sure did , on the courier in the morning, and two spare arms

 

[SpeedfreakNZ]

Matt, your a legend

I will have some video to share of us trying night flying on Thursday, some out of control UFO moments are guaranteed

 

[Efliernz]

Thats interesting, I am new to Multi's and Gyros in general and I have had the same problem with my KK board quad. Now that I am getting a little cocky flying the thing, if I do a loop or even a hard turn the board loses its lock and I have to hold a stick or sticks over to hover, I thought it was my setup

matt, did you get that message about the props, I need another two sets urgently

Yay - it's not just me

 

[Crash]

Yay - it's not just me

I suppose you could be knocking a gyro out of calibration. However I don't ever recall reading anything about that in all the KK and multiwii posts I have read.

I know that some gyros actually have a matching internal gyro sensor to counteract the affects of acceleration. Maybe that has something to do with it?

At this point, I think I would isolate it to either the gyros or the airframe by strapping the machine down and doing a full throttle run-up. Then see how it flies.

Have you asked about this in the KK or Multiwii threads on RCG?

 

[Efliernz]

I have asked rcg (several times over the last 4 months) but it get ignored - probably because it's just me

I'll throw a new design together for the daughters (and the club build tri project). Something really simple and light and not built to carry cameras like mine.

CC here I come