Elevator Wobble on Apprentice STS
02-13-2022, 02:57 AM
#1
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Join Date: Feb 2022
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Elevator Wobble on Apprentice STS
Hello all,
I have this Apprentice STS It seems to have developed a wobble in the elevator constantly moving while in flight and all thought it doesn’t effect flight as such it is quite annoying.
I have not seen anything about this problem so hopefully someone can help.
Any advice will be appreciated!
I have this Apprentice STS It seems to have developed a wobble in the elevator constantly moving while in flight and all thought it doesn’t effect flight as such it is quite annoying.
I have not seen anything about this problem so hopefully someone can help.
Any advice will be appreciated!
02-13-2022, 10:38 AM
#2
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Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 12,856
OK ... questions :
How are your elevators connected to each other or are they separate with own servos ? Is there a long rod from servo to elevators or is servo at tail end of model with short rod ?
How loose is rod in servo arm or elevator horn ?
When on ground and static ... can you move elevators up / down by hand while servo stays centred or still ?
Can you 'pull' elevators out from stab as if hinges are not secure ?
OK ... having looked online ... I assume this is the Horizon Hobby SAFE version ? It has single thin rod from servo via tube ... and also subject to Gyro Stab .....
Therefore question is - have you changed anything with regard to the SAFE settings ? If GAIN is set too high - you can start to make model undulate and as GAIN is increased further - can literally kangaroo along ... basically because the GYRO is reacting too strong and causing model to go past neutral .. GYRO then throws other way .. it repeats.
Another factor in this - wind ... if you set the GAIN for strong wind and then fly in light - the GAIN is too high and you get that same undulation ... this is why its best to have variable gain available while flying.
OK ... another side to SAFE ... you trim out the model and fly happily with SAFE ... then you decide to switch off SAFE ... if the trim was not done while SAFE switched OFF ... then now you can have trim that is not suitable for when SAFE is OFF ...
Conclusion :
Check all physical control connections and hinges - especially if foam hinge - it can crack and looks ok - but when in flight - surface can move about / flex. Also that control rod tubes are secure at ends and not moving / flexing.
Check that servos haven't developed bad centering and that you cannot move arm when powered on.
Once physical checks completed - then proceed to SAFE Gyro settings and how they are ...
How are your elevators connected to each other or are they separate with own servos ? Is there a long rod from servo to elevators or is servo at tail end of model with short rod ?
How loose is rod in servo arm or elevator horn ?
When on ground and static ... can you move elevators up / down by hand while servo stays centred or still ?
Can you 'pull' elevators out from stab as if hinges are not secure ?
OK ... having looked online ... I assume this is the Horizon Hobby SAFE version ? It has single thin rod from servo via tube ... and also subject to Gyro Stab .....
Therefore question is - have you changed anything with regard to the SAFE settings ? If GAIN is set too high - you can start to make model undulate and as GAIN is increased further - can literally kangaroo along ... basically because the GYRO is reacting too strong and causing model to go past neutral .. GYRO then throws other way .. it repeats.
Another factor in this - wind ... if you set the GAIN for strong wind and then fly in light - the GAIN is too high and you get that same undulation ... this is why its best to have variable gain available while flying.
OK ... another side to SAFE ... you trim out the model and fly happily with SAFE ... then you decide to switch off SAFE ... if the trim was not done while SAFE switched OFF ... then now you can have trim that is not suitable for when SAFE is OFF ...
Conclusion :
Check all physical control connections and hinges - especially if foam hinge - it can crack and looks ok - but when in flight - surface can move about / flex. Also that control rod tubes are secure at ends and not moving / flexing.
Check that servos haven't developed bad centering and that you cannot move arm when powered on.
Once physical checks completed - then proceed to SAFE Gyro settings and how they are ...
02-15-2022, 10:07 PM
#3
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Join Date: Feb 2022
Posts: 2
Originally Posted by solentlife
OK ... questions :
How are your elevators connected to each other or are they separate with own servos ? Is there a long rod from servo to elevators or is servo at tail end of model with short rod ?
How loose is rod in servo arm or elevator horn ?
When on ground and static ... can you move elevators up / down by hand while servo stays centred or still ?
Can you 'pull' elevators out from stab as if hinges are not secure ?
OK ... having looked online ... I assume this is the Horizon Hobby SAFE version ? It has single thin rod from servo via tube ... and also subject to Gyro Stab .....
Therefore question is - have you changed anything with regard to the SAFE settings ? If GAIN is set too high - you can start to make model undulate and as GAIN is increased further - can literally kangaroo along ... basically because the GYRO is reacting too strong and causing model to go past neutral .. GYRO then throws other way .. it repeats.
Another factor in this - wind ... if you set the GAIN for strong wind and then fly in light - the GAIN is too high and you get that same undulation ... this is why its best to have variable gain available while flying.
OK ... another side to SAFE ... you trim out the model and fly happily with SAFE ... then you decide to switch off SAFE ... if the trim was not done while SAFE switched OFF ... then now you can have trim that is not suitable for when SAFE is OFF ...
Conclusion :
Check all physical control connections and hinges - especially if foam hinge - it can crack and looks ok - but when in flight - surface can move about / flex. Also that control rod tubes are secure at ends and not moving / flexing.
Check that servos haven't developed bad centering and that you cannot move arm when powered on.
Once physical checks completed - then proceed to SAFE Gyro settings and how they are ...
How are your elevators connected to each other or are they separate with own servos ? Is there a long rod from servo to elevators or is servo at tail end of model with short rod ?
How loose is rod in servo arm or elevator horn ?
When on ground and static ... can you move elevators up / down by hand while servo stays centred or still ?
Can you 'pull' elevators out from stab as if hinges are not secure ?
OK ... having looked online ... I assume this is the Horizon Hobby SAFE version ? It has single thin rod from servo via tube ... and also subject to Gyro Stab .....
Therefore question is - have you changed anything with regard to the SAFE settings ? If GAIN is set too high - you can start to make model undulate and as GAIN is increased further - can literally kangaroo along ... basically because the GYRO is reacting too strong and causing model to go past neutral .. GYRO then throws other way .. it repeats.
Another factor in this - wind ... if you set the GAIN for strong wind and then fly in light - the GAIN is too high and you get that same undulation ... this is why its best to have variable gain available while flying.
OK ... another side to SAFE ... you trim out the model and fly happily with SAFE ... then you decide to switch off SAFE ... if the trim was not done while SAFE switched OFF ... then now you can have trim that is not suitable for when SAFE is OFF ...
Conclusion :
Check all physical control connections and hinges - especially if foam hinge - it can crack and looks ok - but when in flight - surface can move about / flex. Also that control rod tubes are secure at ends and not moving / flexing.
Check that servos haven't developed bad centering and that you cannot move arm when powered on.
Once physical checks completed - then proceed to SAFE Gyro settings and how they are ...
02-16-2022, 11:35 AM
#4
Super Contributor
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 12,856
TBH ... I have no idea when it gets to SAFE ... if it was a standard common Gyro Stab - then its in the programming of TX.
I assume you have Spektrum TX ?? I would google a solution ...
I assume you have Spektrum TX ?? I would google a solution ...
02-16-2022, 06:48 PM
#5
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Join Date: Jul 2008
Location: Cheshire, UK
Posts: 2,078
more questions
Does the elevator oscillate (can you hear the servo moving) when the plane is absolutely stationary on the ground?
Does it continue to oscillate when you apply some elevator movement?
Does the elevator oscillation actually make the plane pitch up and down when in flight?
Can you switch Safe completely? (experienced mode). When SAFE is off does the elevator continue to oscillate when on the ground.
A video of the oscillation would be a great help.
What this is trying to diagnose is whether the problem is with SAFE, the linkage or that the servo itself is defective.
Does the elevator oscillate (can you hear the servo moving) when the plane is absolutely stationary on the ground?
Does it continue to oscillate when you apply some elevator movement?
Does the elevator oscillation actually make the plane pitch up and down when in flight?
Can you switch Safe completely? (experienced mode). When SAFE is off does the elevator continue to oscillate when on the ground.
A video of the oscillation would be a great help.
What this is trying to diagnose is whether the problem is with SAFE, the linkage or that the servo itself is defective.
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