Mhz Mystic S turning problem

[bjornar]

you said you switched from NEU's to Feigao's and still she turns in straight right?
so this doesn't seem to be a motor/power difference between L and R!
does she turn slowly or is it brutal?
are you running L and R flex? that might sounds to be a dumb question but... if not then one flex unwinds and creates more friction so less power at prop is the result.
beside of this, I can't see any water pick up, are they flush to the bottom?

I have tried different combinations. Neu 1515/1Y and Hydra 120, Neu 1515 and Turnigy 180A, Feigao and Hydra 120. All the combinations did not work. I have also tried another servo just for trying. I have not tried different battery packs.
She turns brutal. The flex are left and right and is on the right place. And yes, the water pickups are flush to the bottom.

More pictures. A litle messy in the boat because of all the testing.

[bjornar]

You're running inward. (more stability)
try reversing the rotattion to outward (more speed) AFTER you figure out the issue first!

Thanks for the tips, it will be tried later on

[ED66677]

well... what radio gear are you using? it's full of carbon in there!!! that could be radio glitches!

[ED66677]

are the pick up really flush? can you make a different picture of the bottom? looks like they stick out a little bit?

[bjornar]

are the pick up really flush? can you make a different picture of the bottom? looks like they stick out a little bit?

I would say the pickups are pretty flush. Cant understand thats the reason.
The hull is Carbon/Kevlar and the antenna is out of the boat. See picture.
I am using Futaba 4PK.

[Rumdog]

I pretty much has to be a radio or servo issue.

[ED66677]

yeah flush enough! can't perturb the flow of water in front of any prop!
another question... does she always turn the same direction?

[bjornar]

yeah flush enough! can't perturb the flow of water in front of any prop!
another question... does she always turn the same direction?

She turns both directions.

[ED66677]

if it's not a radio or servo issue, that's probably because one prop comes out of water, the other creates more thrust and then she goes!
here's my theory, if you were running outward instead of inward this may not happen... when a prop comes out of water, as I said, the other creates more thrust, in you case, you have to add the prop walk effect, because you running inward the prop walk effect of the prop that is still in the water amplifies the turn effect, try swapping prop and flex and see what it does!
just an idea!

[Rumdog]

running inward will completely eliminate prop walk. Twin cats with inward spinning props are way less prone to propwalk than any other type of boat. Where is your cg? It may be hooking.

[RaceMechaniX]

My one guess is the servo and/or linkage system. The thin plastic servo horn and cable system for the rudder seem to be the culprit. First, that thin plastic servo horn that comes with the servo is not strong enough, it may be bending and flexing casuing the rudder to deflect. Also it looks like the pull-pull cable system takes a zig zag path to get back the rudder. The extreme angle of the linkge joints to the rudder cannot be helping.

Although not scale or aesthically pleasing, I would try running straight linkages back to the rudder if possible.

Tyler

[BakedMopar]

I'm going to agree with Tyler on this one. With your radio system powered up see if you can move the rudder with your hand. It should take a lot of force and shouldn't move in any direction.

Alps how are you running your batteries? Are they independant or both escs are wired together?

[bjornar]

I'm going to agree with Tyler on this one. With your radio system powered up see if you can move the rudder with your hand. It should take a lot of force and shouldn't move in any direction.

Alps how are you running your batteries? Are they independant or both escs are wired together?

its not possible to turn the rudder. The batteries are independent.

The turning happens all the time. When I drive straight it just starts turning in one direction (more and more) and if I "force" it the other way it just starts turn the other way.

[ED66677]

can you "feel" or see that the boat banks to the outside of the turn? I mean the inside sponson lifts a little bit?

[bjornar]

I just took a video of her. I am driving straight when it start turning all the way round. I try to straighten it up with the rudder and then it goes the other way around and on and on...

http://www.youtube.com/watch?feature=youtube_gdata&v=1XjA9f9JSkw