What to look at when buying a second hand drone

Imagine…
You have been flying your learner drone since Christmas, and you are ready for the next step.
A nice GPS enabled drone to take great pictures is on the short list…


You could of course get a brand spanking new one, but what if funds don’t stretch that far?
Right.. Second hand is also a good option, but what to look out for when you buy second hand?

If you’re on a budget, or you have set yourself one, it is important to get as much value from that money, and that is exactly when things get tricky.
A cheap drone doesn’t necessarily has to be a bad one, it depends on what extra’s it has. You can choose for 1 or more batteries, but you can also choose for less batteries and extra’s like a bag/case and a tablet holder.
Everybody that sells has a different idea on what their gear is worth, respect that but also stay sharp! there might be a better deal.

But say you have found the drone you want, what would be the things to check?
Of course if it flies! that is why you want it anyway… but a flying drone doesn’t have to be a good one!

Before you hand over your hard earned money check the following things to ensure a great time flying.

  • General state of the craft

How does it look? does it have dents and cracks? are there any signs of the drone being taken apart?
If that is the case, ask what happened, and why. the person might be very handy repairing things and all could be fine, but there is always a reason for dents and cracks.


Especially the Phantom 3 and 4 had issues with stress cracks, and that is not bad, you might even be able to fix it yourself! but it is a point to consider before you go and buy the drone. If your buying a Phantom 3, and it has anti stress crack mounts installed, ask if they can be removed to check for cracks under them

Also check the charger, make sure it is in good shape and that the contacts are nice and straight.

 

  • State and functioning of the moving parts and battery

Motors

A drone has either 3,4 or 6 and some even 8 motors, and it is important to check for wear on the motors.
There should be no, or very, VERY little play in the motors, but best is to have as little as possible.

Gimbal

The gimbal, if any, should move around very smooth. There should be no signs of sand or anything.
Any kind of noise coming from the gimbal can be considered as not good.
Here is a video how you can check the motors and gimbal.

Battery

The battery is very important and should be in tiptop shape.
Any signs of damage should be considered useless. A puffed up battery should not be used!
Check the terminals, and ask if you can see how many times the battery has been charged.
If you’re buying a DJI drone you are able to see that in the app.
With a DJI Intelligent battery you can also check the state of the battery by pressing, and holding the power button for 5 seconds. the lights will show how much life is left in the battery as shown in this video.

Once all the physical check have been done it is time to check the rest.
First you should power up the drone and it will do a little system check.

  • Check internal hardware like GPS, Compass and IMU

Once powered up the drone will start to connect to GPS and that should take no longer than 2 minutes to get at least 6 sattelites. Power on the remote and make sure it connects.
In the DJI app you can also check the status of the IMU and compass, check for any errors.
Normally any malfunction will be displayed in the app in a red bar, even in the normal FPV mode.

 

If all sensors are okay check if the gimbal functions correct.
Best is to do a calibration, it will only take 1 minute to do, but it will show you if it is functioning as it should, calibration should finish without any errors.

  • Propellers

Check the propellers for any damage. There should be no damage at all, no dents… nothing!
If the drone only has damaged props make sure you get a new set a.s.a.p.

When you are buying a drone with foldable propellers like the Mavic or Spark check the joints of the propellers. There should be no play.


Now that you have checked the craft it is time for a test flight.
Make sure you have enough sattelites, A DJI will show a green bar that says “ready to go”

When airborne don’t go too high and check for vibrations, there should be none or very little.
Vibration is not nessicarilly bad, it could be propellers that are unbalanced, and it is easy enough to balance them.

When airborne and all systems are good, the drone should stay in place pretty good depending on the wind.
A little up and down and sideway movement is perfectly normal but it should not be all over the place. The drone should also keep it’s heading if there is no stick input.

Fly forward, backwards and sideways and let go of the sticks. the drone should hold it’s position straight away.

If that is all good the drone is in great shape and should be able to deliver hours of fun to come.

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