Problems setting up cyclic

[gpang788]

Recently came into possession of a Trex 500 DFC Pro. This is not my first heli build. I have build and flown trex 450 helis before.

At this point I have completed the build but notice when giving aileron inputs, the right aileron seem to deflect more than the left one by about 1.5 degrees.

My aileron and pitch servo arms are not set perpendicular (set them up the best I can) to the frame and are at a slight offset angle to each other. Could this be the cause of the difference?

I am really scratching my head over this one. Could someone help me out?

[tonys-heli]

what tx and fbl?
did you go through the setup in the fbl?
did you set the cyclic control rods to 90 deg in your setup menu and zero your pitch links at half stick?
same travel in the tx for cyclic?

[gpang788]

I am using a Futaba T8J + Spirit FBL

Yes completed the setup in the FBL as per the instructions. Swash levelled with leveller.

Cyclic control rods set to roughly 90 deg and pitch links zeroed at half stick

Pictures below are taken with throttle perfectly centred

https://ibb.co/8x0sjjw
https://ibb.co/phPkyy2
https://ibb.co/dkXM7dH

[Felix the cat]

At this point I have completed the build but notice when giving aileron inputs, the right aileron seem to deflect more than the left one by about 1.5 degrees.

How are you measuring this ? Aileron action is observed / measured on the cyclic pitch range setting.phase.

Blades parallel to the boom, so technically there is no left or right unless you'd call the rear (advancing) blade left and the front (receding) blade right.

Having said that, when measuring cyclic pitch I've had instances when the two blades are not alike in their CYCLIC pitch readings and has not affected any. I measure by the one above the boom.

My aileron and pitch servo arms are not set perpendicular (set them up the best I can) to the frame and are at a slight offset angle to each other. Could this be the cause of the difference ?

As long as your swashplate is leveled through the range and most importantly at mid-stick you shouldn't have any problems.

I am really scratching my head over this one. Could someone help me out ?

From your pictures, the right side servo arm seems to be sitting higher. Again, no big deal as long as the swashplate travels leveled. When leveling the swashplate with a swash leveler tool you'd want to look for any "light" .......yes light, between the tool and the swash prongs.

As minute a detail it does matter. If you have a light gap in more than one prong, then correct the opposite till the other two close gap. It's called rule the odd man out.

Your buckles / links are regular ones, as opposed to turnbuckles. Regular buckles are finicky given that adjustments are always a full turn away. Which as good as it gets it's never like the fine tuning of turnbuckles.

My hat's off to you......DFC heads are a PITA to set Zero pitch. Guess that's why Align no longer promotes them in new kits.

T8J is a great little radio, I had one for years and it's awesome, it's currently my sim radio.

Hope this helps some.

[tonys-heli]

that's some good info felix
but it all looks good to me.

[gpang788]

Originally Posted by Felix the cat

How are you measuring this ? Aileron action is observed / measured on the cyclic pitch range setting.phase.

I measured them with a digital guage by deflecting the aileron stick side to side. Guess that's not the right way haha...now I know...

Originally Posted by Felix the cat

Blades.....unless you'd call the rear (advancing) blade left and the front (receding) blade right.

Yes, that's what I mean.

Originally Posted by Felix the cat

Having said that, when measuring cyclic pitch I've had instances when the two blades are not alike in their CYCLIC pitch readings and has not affected any. I measure by the one above the boom.

Yes this is what I notice in mine too. There seems to be a fair amount of difference, even though the swashplate is level, as you can see in the pics below:

Originally Posted by Felix the cat

As long as your swashplate is leveled through the range and most importantly at mid-stick you shouldn't have any problems.

Good to know. Guess I will ignore the difference above.

Just did a brief test hover today. I notice that at about 1/4 - 1/3 throttle, the blades seem to misalign a little causing slight vibrations Otherwise, they track good. Not sure what's causing the misalignment though? Should I investigate further or should I just leave it at that and go fly?

[Felix the cat]

.

Just did a brief test hover today. I notice that at about 1/4 - 1/3 throttle, the blades seem to misalign a little causing slight vibrations Otherwise, they track good. Not sure what's causing the misalignment though? Should I investigate further or should I just leave it at that and go fly?

Still on the ground right ? If so, it could very well be ground resonance. Cut-off main blades are awesome for pitch readings aren't they ? I use them all the time.

Bring it up into a hover, blades at eye level, if sharp and tracked, ENJOY !

Chinook ground resonance - back (0 min 39 sec)

[tonys-heli]

when doing the setup, mark one blade and use that, set zero pitch and track the other blade to that. or what I do is, once out of the setup menu, find your marked blade, go to half stick and set your pitch gauge on it, while blade is over boom, and get zero again, then take it off, rotate the head carefully and put it on the other blade and read the gauge.. zero that blade and then they should track perfect.
other than that, I don't mess with checking the other blade for anything as long as it tracks fine.

[Gladius]

When you swap the pitch gauge between blades, do you re-zero it? If not, it will give different readings.

[tonys-heli]

Originally Posted by Gladius

When you swap the pitch gauge between blades, do you re-zero it? If not, it will give different readings.

I usually don't cause I move it very little during the swap. but I have re-zeroed it as well, with the same results.. dead on tracking.

[gpang788]

Originally Posted by Gladius

When you swap the pitch gauge between blades, do you re-zero it? If not, it will give different readings.

Never occurred to me to do that. Will try it out

[gpang788]

Originally Posted by Felix the cat

Still on the ground right ? If so, it could very well be ground resonance.

Resonance on 2 blades, possible?

Originally Posted by Felix the cat

Cut-off main blades are awesome for pitch readings aren't they ?

Absolutely Felix