Walkera Scout Improvement Program.

I am starting this thread to document my Scout Improvement Program.

I like the scout it is a cool little quad. (Particularly the Back Carbon body version.) But has a number of flaws in its default shipped state. But it also has great potential. e.g. Converting from X4 to X8.

I have 2 generic Scout X4s and all the parts to construct one but include a DJI flight controller to do a direct comparison of Walkera vs DJI flight controllers. This is unlikely to be a fair comparison as the A2 FC from DJI cost more than the RTF Scout.

The end state of this little program will be 3 Carbon Black Scouts. 2 upgraded with Dual GPS plus shielding, One of these converted to an X8, and one built from parts as a test mule to test various DJI FC combinations. I have bought for this test rig.

DJI Naza M Light with GPS
DJI Naza M V2
DJI Wookong M with GPS pro
DJI A2 M with GPS Pro Plus.

In case you haven't guessed I am retiring from the workforce in 19 days (and Counting) and I have my retirement planned so I have no chance of getting bored. (I have a large room filled to the brim with "Projects".)

I have the same in my Project room for 3 Tali H500s. And another set of DJI FCs. I like the Tali Too.

So the first step was to do the Dual GPS upgrade on one of the RTF Scouts and test both of them simultaneously so a direct and conclusive comparison can be made. Two Scouts side by Side one upgraded one not.

The results are in the video below.

The Dual GPS / Glonass upgrades were sourced from:

GPS MODULE FOR SCOUT X4 with GPS and GLONASS

Now you need to be careful here. The current shipped GPS model on the scout has the same GPS model number shown here. The important detail is that the GPS receiver needs to be the BeStar BS-300 with the Cirocomm T0010 GPS antenna. The Shipped GPS is a BeStar BS-300 with the Cirocomm 580 GPS antenna. (Which is awful)

Walkera have removed the BeStar BS-300 labelling from the latest shipments of the GPS upgrade to avoid confusion.

Pictures Attached.

 

Step 2 The introduction of a Ferrite Choke to the GPS wiring. This is to prevent RF from the ESC / Motors and the 5.8 Ghz Video transmitter overpowering the GPS.

I have noticed that when a gimbal is attached to these Scouts the GPS reception and number of sats locked tends to reduce. To make matters worse the Scout is pretty well balanced for CG without the Gimbal and iLook+ camera. But when attached it has a significant nose heavy attitude and forward lean. So losing Sat Lock a flyaway will scream forward.

Another interesting issue I have found with my initial GPS testing is that you "Do not want" to takeoff in GPS mode if you arm the Scout motors on uneven ground. Either with the sticks or the Auto takeoff switch.

For some reason in GPS mode on uneven ground the IMU calibration at motor arm causes the GPS and IMU to fight each other. You will also notice if you throttle up slowly the Motors will randomly stop as the IMU tries to level the Scout while still on the ground. I have tested this on both Scouts and it is consistent behaviour. Once airborne it will start to rock and then flyaway and crash. Chopping the throttle in this scenario has absolutely no effect. I have not tried this with the upgraded GPSs as it costs me a set of props per test. (It flips on its back and crashes props down with the motors not stopping as its still trying to self level. And eats the props.) You have to flick the TX to manual to stop the motors.

So big warning. Do not Arm and fly in GPS mode off the ground unless the ground is Absolutely level. I will film this prop stopping behaviour and post in this thread. i will try and not film a resultant crash.

So next Step in the Upgrade program is the Ferrite Chokes. I have gone down this path rather than just grounding the Shield as an inflight aircraft has no ground as such. There is no way to dissipate the RF energy accumulated in the Shield. The descriptions of shielding I have seen on the web have connected the Shield to the "-" battery connection on the receiver. To me this means that you are pumping RF into the RX itself. Whilst this may protect the GPS from RF it introduces RF to the "-" battery line to the RX and the Flight Controller. This to me can create other non GPS related issues.

I have a couple of EagleTree Vector flight controllers and an elogger with GPS The best reception I get on any GPS is the elogger GPS that has a Ferrite Choke preinstalled.

This purely acts as a Low Pass filter allowing the GPS data transmissions to pass but blocks the RF from getting to the GPS itself.

So the outcome of the Step 2 tests is in the video below.

One thing I did get wrong was after upgrading the Scout with the choke and new GPS / Compass I did not do a new calibration I only realised this when I subsequently attempted to fly this Scout

In the video you will see that the uncalibrated Scout with the choke was a couple of sats behind the non choked version. But they did sync up after a while with about 7 blue blips, or 11 Sats locked each.

I subsequently calibrated the Choked Scout and flew it. The video shows it hovering incredibly stably with 10 Blips. 14 Satellites in its lock. It hovered within a couple of inches continually. And maintained a 14 Sat lock for the entire flight.

Next steps will be to test the Scouts Choked and Un-choked with a inflight 5.8 Ghz video transmission.

The chokes were sourced from here.

Soft Ferrite Rings 16x7x9 (5pc)

Installation Pics. The ferrite ring is quite large and you need to ensure that it fits with the flight controller and allows the 2 halves of the Scout to clip together unhindered. I had to move it around a bit so it ended up being placed next to the FC.






I will take a break from this for a while and do some flying. Stay Tuned.

 

See the end of the Second video. Its the most stable loiter hover I have ever seen from a Scout. 14 sats in the lock.

 

Thanks have a 3DH Gimbal as well to test and compare.

Yes always short of breath now. Now a non smoker but a bit late.

 

Thanks, I will have a look at that. Its unclear how that would help to me but I will investigate and try.

 

Not yet, Will be a while. I am closing out my work career and retiring on the 18th of December so really hectic. Still got a Voyager 3, and a new Tali that I have not flown. And the Marina just put my Motor-yacht back after the marina upgrade so I have access to it again. Its been without power for about 3 weeks, so I need to spend the weekend on her.