AllMYRC.com-A Radio Control Helicopter, Airplane and Car Community » R/C Helicopters » Ask the Pro's » Nick Maxwell

[Kenny]

Hey Nick

Question on mixes. I have watched you fly several times now and have noticed on some models you will use a mix in the transmitter to correct some of the flight controls on flybared machines.

So far I have been trying to learn how to correct the model in flight. Basically pitch to elevator, pitch to rudder, elevator to aileron etc.... So if you could give me some guide lines to get started that would be great.
My fear about this is, putting the wrong mix in the tx and botching a perfectly good model. My goal is of course to make the model fly better.

Last thing, I assume all of this will go away using the flight control system?

Thanks

[Nick Maxwell]

Hi Kenny,
Nice to see you this weekend.

Regarding mixes, it usually seems be a series of about 4 "core" mixes then 4-6 additional ones that can be used to tweak little things you notice the heli doing.

Usually to start off, on the ground, from bottom pitch to top pitch try to get the swashplate traveling as true and flat as possible using the End Points to adjust the servo throw.

Seems like these are the first 4 "core" ones, in the order that (IMO) is the easiest to tell what the heli needs:

1) Pitch to Aileron- to set this, let the heli fall slowly upright in medium paced forward flight and proceed to start a climb out. Observe which way the heli drifts (regarding aileron input). Just adjust that mix number -for positive stick input number- until it doesn't want to roll out of the climb. Do the exact some thing inverted -for the negative stick input number- until both are as close as possible.

2)Pitch to Elevator- this is the exact same method as the P-A just watching for the elevator to drift. The additional thing to watch here is to make sure it maintains the same forward heading speed from the decsent.

3)Elevator to Aileron- This is just for if the model pulls to one side consistantly when entering a loop/stall turn/any elevator input manuever. Applies for both up and down elevator inputs. Just doing inside and outside loops going away from yourself seems to show the best angle to see which side its falling off to.

4) Aileron to Elevator- This one is for roll correction if you find your heli consistantly corkscrewing through rolls. With certain blades/paddles/RPMS/etc. this might not even be needed. But if it is, just take note of it the nose is going high or low in the 1/2 roll to inverted. Nose high needs a slight up elevator mix, nose low needs a slight down mix. Same for both right and left rolls.

Depending on radio brand, I beleive most of the top end radios have graphs to see the mixes, if not, there will be dual numbers one for one direction whether it be pos-neg, right-left, or up-down depending on what the slave control is.

The follwoing mixes don't make really big differences, but can be useful on some models:

1) Elevator to Rudder- this is to correct any consistant yawing through loops/flips

2)Aileron to Rudder- to keep the nose leveling during the knife edge portion of the rolls (this can be tricky with HH gyros, as the entry on the roll has to be strait, if not the HH gyro will just maintain the offset tail heading). Usually this isn't needed.

3) Aileron to Pitch- if on the ground under aileron inputs the swash plate climbs or descends applying pitch to the blades under just aileron inputs. Usually this leads to the "barrell" effect during vertical rolls.

4) Elevator to Pitch- " "


All of these really should only need very slight amounts (depending on radio numbers) anywhere from 1%-10%. And the great thing is, if you do happen to go the wrong way with the mix, it of course is not a drastic enough change to make a crash, but also, if you decide not to mess with it, just inhibit the mix and it'll be back to normal

And as you mentioned, thankfully, with the Flight Controls that basically takes care of all that

Thanks!
Nick

[Bobby Barr]

Nice!

[Kenny]

Hi Nick,

This past weekend was a lot of fun!
By the way, my wife tried to throw my old hat away. I told her NO

Thanks for the information Nick. This is great!

Question:
Just for clarification, if you have a few clicks of trim on eleavtor or aileron in a hover should you remove those before adding in any mixes in the model? I have always understood a small amount would be exceptable.

[Nick Maxwell]

The trims are fine (IMO) its the subtrims that may cause some weird swash walking. While the cyclic trims affect the CCPM trim as a whole, subrims only affect individual servo trims that could change the total throws and curves of an individual servo.

Poor hat... it should be framed

Nick