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Servo issue

yankee24

Junior Member
#1
I've searched for an answer with no success, so here's my first post.

Just put together a MPX Blizzard with HS55's and all four servos only have about 10-15 degrees of throw each way….? My only other experience with HS55's was on an Easy Star II and they have about 60 degrees (30 each way)

Any suggestion would be greatly appreciated.
 

jetpackninja

More combat please...
Mentor
#2
Are you talking about the amount of throw on the control surfaces?

Or, are you talking about the actual travel of the servo arms?

What radio are you using?
If you are using a programmable radio, you may be able to adjust the amount of servo travel. On my Dx6i I typically dial mine up to 125%, especially on my flying wings.

It is preferable to achieve the amount of desired throw mechanically first. Use a hole closer to the control surface for more movement or a hole further away from the center of the servo arm.
 

yankee24

Junior Member
#3
Thanks for your reply, I'm talking about the servo arm travel. I use a DX6i as well and I did dial up to 125% before posting question.

I'll also note my only other experience with HS55's was on an Easy Star II and those servo arms travel at least 30 degrees each way.
 
#5
...odd

:confused: ...odd, do you have a servo tester so you can check them without your RX/TX...i had tons of problems with all kinds of rc-stuff but never something like that before...have you tried to reset the model in your TX to make sure there is no programming error somewhere?...just guessing here :confused:
 

xuzme720

Dedicated foam bender
Mentor
#6
It almost sounds like you have low rates selected. Throw values of 125% should get you just past 60 degrees of throw since HS55's definitely have 60 degrees of travel, as most conventional servos will. I think Warbird has a very good idea with the servo tester or resetting the memory for that model. That will get rid of any spurious programming and hopefully solve the travel issue.
 

quorneng

Active member
#7
yankee24
I presume you are using the V tail mixing option on your DX6i.
This is likely to limit the servo movement on say elevator as it has to allow for rudder movement as well.
For some reason the DX6i does not do this very well. I had exactly the same problem with the elevons on my FD2. Even with 125% set it did not make much difference.
I eventually resorted to a dedicated mixer unit which did a much better job giving nearly full travel with a single command and a degree of over travel when both were applied.
 

xuzme720

Dedicated foam bender
Mentor
#8
Good catch, quorneg. I didn't even think about the v-tail mix since my radios all give me full throw on v-tail...but then, I don't have any Spektrum's
 

yankee24

Junior Member
#9
I'm using the Thunder 54 ESC with 3 AMP BEC.
I'll try resetting in transmitter first, I do not have a servo tester unfortunately, best purchase one.
I am V-tail mixing with DX6i, as well as Dual aileron, so using rudder, aileron, elevator and aux1 plugs.
I'll try running Y-harness for ailerons to see if it makes any difference as well.
And YES, it does seem like it is just set to low rate… Stumped on this one.
 

xuzme720

Dedicated foam bender
Mentor
#10
I'm using the Thunder 54 ESC with 3 AMP BEC.
I'll try resetting in transmitter first, I do not have a servo tester unfortunately, best purchase one.
I am V-tail mixing with DX6i, as well as Dual aileron, so using rudder, aileron, elevator and aux1 plugs.
I'll try running Y-harness for ailerons to see if it makes any difference as well.
And YES, it does seem like it is just set to low rate… Stumped on this one.
Try disabling the v-tail mix and see if you have full travel on the servo's. if you do, then you know it's only the mix causing it and can go to a dedicated wired mixer to help solve it as quorneg did.
 
#11
I well try all of the above starting with resetting tx and disabling mix on Tail/Aileron as soon as I can get back in there… I'll post up what I find…… or don't find.
 
#12
Okay, resetting tx and binning didn't do anything different…
Disabling dual ailerons didn't change anything either…..
Disabling V tail mix did change things however… when V tail mixing enabled I have about 2.5-3mm of throw on the right side (at control surface) and 3mm on the left for both rudder and elevator. When not enabled right side has about 5.5mm and left side about 6mm of throw at the control surface. Guess I'll pick up and install the dedicated mixer for tail, however I assume this bird would fly okay with 3mm of control surface throw on tail.
That said can anyone who flies the Blizzard confirm if 5mm up and 5.5mm down of throw at control surface for ailerons be okay? I know the manual states:

Control surface travels:
Measured at the broadest chord of the control surfaces
Ailerons: 14 / 6 mm +/-
Elevator: 5 / 5 mm +/-
Rudder: 7 / 5 mm +/

So, I assume requiring 14mm up and 6mm down for ailerons that 5mm-5.5mm both ways well not be okay…

Still stumped !!!
 

jetpackninja

More combat please...
Mentor
#13
V tail mixing-is similar but different than elevon mixing right? So left right (rudder, not aileron) only gives half the range. Have you tried joining the stick movements i.e. full left rudder combined with full up elevator?

Another way to confirm would be to set it up on a channel with a regular wing type selected. Does full rudder and full elevator act as suspected now?