Trimming (Rudd mix Vs Side thrust)
 

Hello all
I am having trouble trimming my Pattern model and need advice. My model is a 2x2 Matrix (similar to a CPLR Alliance) running an RX140 with a 16x12 APC.

Is it better to use side thrust or a rudder/throttle mix? How much side thrust becomes to much?
At the moment I have about 3.5 degrees of side thrust and 4% throttle/rudd mix. Up lines and down lines are fairly straight althought with varying speeds the model tracks off line such as through a 1/2 loop.

Also I have trimmed the elevator to give a good vertical downline, while having to hold a far bit of up elevator to maintain level flight, Inverted requires little down elevator stick. Is it better to just hold some stick while level or use a mix?

Help me pattern pros[8D]
Anthony

RE: Trimming (Rudd mix Vs Side thrust)
 

Provided your model is actually built straight(eg no banana fus,fin not warped,&c.),it should be possible to get very,rather than fairly, straight,lines,using just the methods you've described.
If you have to use a bit of throttle-to- rudder mix, try this:
First, climb vertically directly into wind,at full power,and use the ordinary rudder trim,to add right trim,to get a truly straight vertical line.
Then, fly level, again directly into any wind, away from yourself,again at high power, and reduce power to tickover.
The model will yaw right as it slows.
Add enough left throttle-to-rudder mix, at this low power setting, to prevent the yaw.
This may do all that you need---or, you may need to use one of the multi-point mixes,to find the left rudder percentage mix needed, at differing throttle settings up to around mid-stick on the throttle.
I think you'd find it more comfortable to retrim the elevator to give level flight, or just a very slight dive, whilst upright.
Then, if necessary, adjust the c.of g. to give just a slight dive whilst inverted---or,better, the model holds a 45 upline after a half roll to inverted,with no tendency to drop its nose after the half roll.
(This is assuming that you've set the engine downthrust to give a straight vertical power-on climb).
With most modern designs, with the decalage set so that the wing is 1/4 to 1/2 degree positive relative to the tail, the power-off downline will then show a small tendency to pull to the canopy, if you've set it up as above.
So,then, you can use a small percentage of down elevator-to-low-throttle mix (typically just one or two percent) to get the downline straight.
You won't notice it flying level at low power(landing approach for example), and it feels a lot easier than constantly having to hold up in at all power settings during level upright flight.

RE: Trimming (Rudd mix Vs Side thrust)
 

I think you'd find it more comfortable to retrim the elevator to give level flight, or just a very slight dive, whilst upright.
Then, if necessary, adjust the c.of g. to give just a slight dive whilst inverted---or,better, the model holds a 45 upline after a half roll to inverted,with no tendency to drop its nose after the half roll.
(This is assuming that you've set the engine downthrust to give a straight vertical power-on climb).
With most modern designs, with the decalage set so that the wing is 1/4 to 1/2 degree positive relative to the tail, the power-off downline will then show a small tendency to pull to the canopy, if you've set it up as above.
So,then, you can use a small percentage of down elevator-to-low-throttle mix (typically just one or two percent) to get the downline straight.
You won't notice it flying level at low power(landing approach for example), and it feels a lot easier than constantly having to hold up in at all power settings during level upright flight.

The upline on power is straight up or near enough. I'll try and move the C.G back slightly, last resort will be to adjust the tail incidence.

cheers Anthony