RunRyder RC
WATCH
 1 page 681 views Post Reply
HomeScale✈️AircraftScale HeliScale Helicopter Main Discussion › Hirobo ch-47 weird problem.
07-30-2012 10:27 PM  9 years ago
Topic Vote0Post 1
spy29

rrApprentice

USA

MyPosts All Forum Topic
Hirobo ch-47 weird problem.
hello all,
with the help off "doorman" i have finally got my hirobo ch-47 to hover., but i have noticed a weird problem..While in hover
there was a significant YAW and roll issue.and once i got it trimmed both mechanically and on radio..heres what is saw while hovering 5ft off the ground.

..the back rotor disc/plate is tilted to the left,and i do not know how to correct.

heres what happens:
on the ground on target (gv-1) headpeed of 1525 ,(just before lift off), Both front and rear rotors are level with each other.

BUT Once its in Hover the Rear rotors show a significant
"tilt" to the left ( front is level) as if the frame twists.
,,Nothing is loose or crooked when on the table all blades track
straight..
anyone encounter this?. any inputs. OS 50HYPER MOTOR.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
07-30-2012 11:23 PM  9 years ago
Phoenix NOTAR

rrApprentice

Tallahassee, Florida USA

MyPosts All Forum Topic
This is very normal (on these models) based on (gyro) yaw input. That is how the Tandems rotate, opposite roll (tilt) on the front rotor verse the rear rotor.

To minimize the tilt that you see, the collective pitch of the front rotor verse the rear rotor can be adjusted so that a "yaw" input is not needed to hover. BUT, this collective delta will also vary the angle the helicopter will sit when hovering (slightly nose high is desired). Depending on the direction the rotor spinning, adding collective will increase the tendency for the model to yaw in the opposite direction.

Your model is naturally trying to yaw nose left in the hover, so the gyro is adding a nose right command, resulting in you seeing the rear disk tilting left relative to the front disk. Assuming that the rotations are stock Hirobo (not scale), if you reduce the collective pitch on the front disk (change the length of all 3 rods to the head) it will reduce this tendency. Adding collective pitch to the rear head will do the same thing. You can do one, the other, or both

Sandy
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
07-31-2012 04:43 PM  9 years ago
Copter Doctor

rrProfessor

Enterprise/ft.rucker ,al- home of army aviation

MyPosts All Forum Topic
Sandy is correct, you see it as well on the fullsize chinook.drive a rotary, fly a rotorcraft
SHARE  PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
08-01-2012 05:07 PM  9 years ago
spy29

rrApprentice

USA

MyPosts All Forum Topic
Success !!., sandy/phoenix notar was right..I Rechecked both heads leveled the swashplates (meticulously) , reduced gv-1 headspeed a little. and added pitch to the rear rotor and viola, chinook.hovered with very little yaw and no roll/sideslip at all.. all it needed was a 5 subtrim at the rudder and its perfect.
having half turns on the hirobo links is the key, the chinook is very sensitive to even half turn changes to he links
..flew a round a bit.left to right..landed due to high winds..
thankx sandy..and stan,,, i can sleep well again
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 681 views Post Reply
HomeScale✈️AircraftScale HeliScale Helicopter Main Discussion › Hirobo ch-47 weird problem.
Print TOPIC

 3  Topic Subscribe

Sunday, September 26 - 1:13 pm - Copyright © 2000-2021 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online