Not flying straight

[Raptorman0909]

This issue of the drone not flying straight comes up a lot and you get the usual advise to calibrate the IMU and compass etc., but there's a couple other things it could be as well. You want to calibrate the sticks to make sure the pots are centered and you also want to make sure you're not accidentally putting some side stick as you're flying.

A good way to check this is to download the CSV file for the flight which you can get from HealthyDrones and look at the values for the sticks. You have four values: rc_elevator, rc_aileron, rc_throttle, and rc_rudder and when your hands off the sticks so they're centered the values should all be 1024. The thing to check for when you have video that you think should be straight but isn't is the value for rc_aileron -- when flying straight this should be pretty near 1024 and if it isn't you are probably putting some side stick force without knowing it. This is not hard to do when wearing gloves.

So, if you have this problem download the CSV file and then sync it up so you know what time in the CSV file (column G) is the same as the video time. Just remember the time in column G is in milliseconds so divide by 1000 to get the actual seconds and convert the video time into seconds to match. It's a good idea to just play with this while watching a video so you get a handle on what the values mean.


Brian

 

[GadgetGuy]

The stick inputs are also available in the Flight Log, when you replay the flight, if you click on the transmitter icon.

 

[F3honda4me]

Yep I catch myself doing this fairly often. Moving the stick ever so slightly causing the craft to go a direction I didn't intend. I changed my expo to .2 to .25 which helped a lot.

 

[Raptorman0909]

The stick inputs are also available in the Flight Log, when you replay the flight, if you click on the transmitter icon.

Which Log Viewer are you referring to?


Brian

 

[GadgetGuy]

Which Log Viewer are you referring to?


Brian

The syncable Flight Log within the DJI GO or DJI GO 4 app, that you can select within the app, and play back in real time 1x, or at 2x, 4x or 8x.

 

[Raptorman0909]

The syncable Flight Log within the DJI GO or DJI GO 4 app, that you can select within the app, and play back in real time 1x, or at 2x, 4x or 8x.

I've never seen or used the log viewer with Go, never even knew one existed.

How do you access it?


Brian

 

[Traveler]

I've never seen or used the log viewer with Go, never even knew one existed.

How do you access it?


Brian

Follow these screen shots.

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[TK-421]

I had the same problem on my first P4P (already sent back)...I reviewed a flight last night where I was pushing full forward stick (no side rudder/yaw/pitch) and the P4P traveled diagonally.

Then I went full stick backward and the P4P traveled slightly diagonally the opposite direction. Wonky.

Yes, compass was perfect, fresh IMU cal, no other stick inputs, and RC cal was fine.


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[Raptorman0909]

Follow these screen shots.

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Thanks, the icon on my Go app (Android) was a little different but still found my way there. Amazing that I had no knowledge of this till now...


Brian

 

[NikitaMaru]

also have this problem ? already made all the diagnostics and calibration, any other thoughts ?

 

[GadgetGuy]

Crooked cameras are the most common culprit. If the camera is facing left or right by 5-10° or even by a few degrees, you will always be flying crooked. Out of four P4P's, two of the four had cameras misaligned, from straight facing, by 5° or more! No amount of IMU or gimbal calibration can fix this. Replacement is the only option! Take a ruler and place it across the front struts and look down from above, and see if the front lens of the camera is parallel to that line, or tilted left or right. Two of mine were noticeably off! Fly along the center of a long straight line like the middle of a street, using the camera FPV, and later look at your stick inputs and the direction of the triangle heading of the drone on the recordedFlight Log, with stick inputs displayed. It will be flying slightly sideways and your yaw stick wll show constant input to maintain that straight line.

 

[TK-421]

Crooked cameras are the most common culprit..

Yep. No need to send it back. Here's the fix:

With the P4 or P4P turned off, gently turn the camera as far as it will go in the opposite direction that it is tilted toward when powered on...then keep turning it a bit. There are rubber grommets internally holding the floated gimbal unit in place, and turning the camera beyond its throw will realign the grommets and make the whole floated camera assembly centered again.

Turn the P4 back on and see if the camera is facing straight again. You might overshoot and need to twist it back in the other direction.

This worked for me.


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[GadgetGuy]

Yep. No need to send it back. Here's the fix:

With the P4 or P4P turned off, gently turn the camera as far as it will go in the opposite direction that it is tilted toward when powered on...then keep turning it a bit. There are rubber grommets internally holding the floated gimbal unit in place, and turning the camera beyond its throw will realign the grommets and make the whole floated camera assembly centered again.

Turn the P4 back on and see if the camera is facing straight again. You might overshoot and need to twist it back in the other direction.

This worked for me.


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I tried this as well, and it "worked" but has resulted in gimbal squeaks and vibrations that were not present previously, and has not stayed straight. Several others having used this "fix" have also reported that it doesn't stay that way! It may stay that way for a while, but if it is that easily dislodged in the first place, and twisted back so easily if loose, it will likely dislodge again, when you least expect it. If that ever happens in flight, or before you notice it, you will be flying crooked again, which can easily lead to a crash when flying close alongside objects, which are just outside the 60° FOV of the OAS! Happened to me before the fix! Highly recommend replacement, instead of the strangling the chicken "fix" which is only a McGuyver fix for in the field, like a solid rubber tire for a flat, until you can get a real one!

 

[F3honda4me]

I tried this as well, and it "worked" but has resulted in gimbal squeaks and vibrations that were not present previously, and has not stayed straight. Several others having used this "fix" have also reported that it doesn't stay that way! It may stay that way for a while, but if it is that easily dislodged in the first place, and twisted back so easily if loose, it will likely dislodge again, when you least expect it. If that ever happens in flight, or before you notice it, you will be flying crooked again, which can easily lead to a crash when flying close alongside objects, which are just outside the 60° FOV of the OAS! Happened to me before the fix! Highly recommend replacement, instead of the strangling the chicken "fix" which is only a McGuyver fix for in the field, like a solid rubber tire for a flat, until you can get a real one!

You're the first I've heard that said it doesn't stay straight. Where are the others that said it too? Everyone that I saw that did the fix has said it has not reocurred both here and on RCG.

 

[GadgetGuy]

You're the first I've heard that said it doesn't stay straight. Where are the others that said it too? Everyone that I saw that did the fix has said it has not reocurred both here and on RCG.

Here is one: RC Groups - View Single Post - Official Phantom 4 PRO ***Owner's Thread***
Despite Blade's reassurances that gimbal squeaks are normal, when the twisting results in gimbal squeaks, and none of my other aircraft have any gimbal squeaks, no matter how they are tilted by hand with the power on, I am not convinced. Squeaks are a sign of vibration which can lead to slipping again. On another note, it occurred to me that the complete lack of gimbal flips on my other P4 and P3P aircraft might be due to the extra weight of external batteries attached, which makes them more stable.

 

[morph]

My p4p would not fly straight tried lots of things to cure it. Then I noticed one motor getting hot other 3 cold. So I rolled back firmware now all is good and cured, it also cured the camera and gimble problems.


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[GadgetGuy]

My p4p would not fly straight tried lots of things to cure it. Then I noticed one motor getting hot other 3 cold. So I rolled back firmware now all is good and cured, it also cured the camera and gimble problems.


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Which camera and gimbal problems?

 

[morph]

All of the above also camera nodding up and down when first turning on


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[GadgetGuy]

All of the above also camera nodding up and down when first turning on


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All of the above is not helpful when alluding to camera and gimbal problems that have supposedly now been fixed by a firmware downgrade. Can you please be more specific? Also, the camera nodding up and down at boot up is perfectly normal. Are you saying it now no longer goes through a full motion test, including up and down, at boot up?

 

[morph]

No mine continuously nodded up-and-down and wouldn't stop. Now it just goes through the normal start-up procedure and all is good


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