MK to WKM conversion

[RTRyder]

Now that I have the small APV quad flying under a Naza controller, the next step of the project was to swap out the Mk stack on the Droidworx AD6 for the WKM I removed from the quad. Yesterday I spent the better part of the day performing the transplant surgery and just before dark I was able to make the first flight of the AD6 with the WKM in control. I have to say in the year I've had the AD6 flying it has never flown this smooth or stable, the difference between the Mk and WKM flight control systems is very noticeable. The other thing I noticed is the AD6 doesn't seem to be plagued by the slight wobble that the larger hex I have used a WKM on had, from what I've been able to see of the AD6 in flight so far is that it's rock steady and looks like it's going to be a great platform for APV, better than it has been so far.

One minor problem to be sorted before I can get it out to a field and really fly it, after the seccond flight the #4 motor lost a phase when I went to start the motors. Initially I though it was an ESC so I swapped it out only to have the problem return as soon as I got outside to test fly. It appears to be an intermittent problem with either the wiring between ESC and motor or in the motor itself. In any case it won't be leaving the ground until it's 100% sorted as in in flight failure is not something I want to deal with. I have a set of Avroto sitting idle at the moment and that may become the fix, problem is they aren't the short shaft version which is what he Droidworx frame requires, so to use them they all have to come apart so I can shorten the shafts on the lathe, looks like I won't be flying the WKM AD6 anytime real soon.

Ken

 

[iceman]

Hi Ken, I have the AD6 with WKM FC but it's no where near as stable as it should be, I posted a question regarding my prop size (using APC 13x6.5) and I hear your results may be better with smaller props. I was wondering what props you use and would smaller improve my stability. I realise all craft are different (my total takeoff is 5kg).

 

[Droider]

@ Iceman.. which APC props are you using? Motors? Batteries?

Dave

 

[iceman]

Hi Dave, I'm using 13" x 6.5e props, 2X 5000mah 4s, Pulso U28 (2214/22) and HiModel Pro 30amp esc (I'm also not sure of correct timing for this motor, esc set at medium).

Andy

 

[RTRyder]

A quick update, new ESCs arrived and have been installed, the WKM/AD6 has now done a few test flights and I'm quite happy with the performance so far. What I'm seeing as I'm getting the gains dialed in is that it wants 10 inch props with just the basic lightweight airframe! Using the Graupner 11 x 5 on the big Pulso motors it's almost impossible to get rid of all the slight wobble at the current RTF weight. As a test late yesterday I added about 3 pounds of weight in the form of a much bigger main battery and another 4S pack strapped to the camera platform. I dropped the basic gain settings to the mid 200s and put the ATTI gains on a TX slider. Amazingly smooth flight at a much lower ATTI gain than I would have thought it should have!

It was a little bit windy and the AD6 flew the smoothest I have yet seen a WKM do in windy conditions so it appears I have two options, I can use smaller 10 inch props at a lower RTF weight, or pack on some extra pounds to fly with the 11 inch props. I think 12 inch props are not going to work at all on this setup unless the RTF weight increases significantly with the resulting loss of flight time. I'd rather keep it a bit on the light side and use smaller props to give me the most time in the air that I can get.

This pretty much confirms something I've suspected for a while now, large multis can fly quite well on the WKM provided they're heavy enough for the amount of lift the props are generating. I tend to build as light as possible so that explains some of the issues I've had and the necessity of putting smaller props on to get the best flight characteristics. People that are getting good results with larger props than I'm using on a similar setup probably have a higher RTF weight that makes the bigger props the right choice for their setup. More testing to be done and sometime today I'll try to find the time to get the older AV130 hooked up to the WKM on the AD6 and dialed in as best I can. Parts for the bent 130 that goes on the CS should be here by 10:30 AM and the new ESCs arrive tomorrow so I should be back to full APV capability by the end of the weekend, now I just need to get the NEX 5N repaired and I'm good to go.

Ken

 

[Droider]

@ Ken nice to here.. have you changed the new ESC timings? what are they set at..

Dave

 

[GGoodrum]

Just getting caught up, reading all the threads here. Ken, did I miss the one where you crashed your CS6?

I think you are spot-on with your conclusions regarding weight vs prop size. I just got my first Naza/F450 in the air, and I'm having a heck-of-a-time getting the gains adjusted to remove the wobble. This thing is way overpowered, with Graupner 11x5s on 4s. I don't have any 10" Graupners, so I went with the 11x5s. Even with precisely balancing the stock 10x4.5s, I still get a slight bit of the high frequency vibrations, that I don't see with the Graupners.

-- Gary

 

[RTRyder]

@ Ken nice to here.. have you changed the new ESC timings? what are they set at..

Dave

Only things I changed on the new ESCs was to set the battery type to NiMH, the cutoff voltage to low, and also the timing mode to low since the Pulso were clicking away pretty good on medium. Didn't really make any difference in the clicking going from medium to low, I'll try high to see if that helps, if not I'll just go back to medium and leave it at that.

I got a couple flights in just before dark with a GoPro setup on the old AV130, the video actually looks pretty good other than the occasional twitching of the mount servos which is why I don't generally use this one for video. I'm going to hook the programmer up to the serovs and see where they're set, I did manage to get this one working fairly well with the other WKM when it was on the Y6 but reprogrammed them afterward when I had the 130 under my MK Hexa V1. Now if I can just remember how I had them set on the Y6 I may be able to get some reasonably decent GoPro video with the AD6...

Just getting caught up, reading all the threads here. Ken, did I miss the one where you crashed your CS6?

I think you are spot-on with your conclusions regarding weight vs prop size. I just got my first Naza/F450 in the air, and I'm having a heck-of-a-time getting the gains adjusted to remove the wobble. This thing is way overpowered, with Graupner 11x5s on 4s. I don't have any 10" Graupners, so I went with the 11x5s. Even with precisely balancing the stock 10x4.5s, I still get a slight bit of the high frequency vibrations, that I don't see with the Graupners.

-- Gary

I guess you did miss it, New Years day not quite 6 minutes into a flight as I was flying back to the takeoff point and descending it did a backflip onto it's side then proceeded to roll and pogo off the AV130/Nex 5N and wind up more or less right side up again. Bent the H**l out of the AV130 and busted the NEX, but other than a couple broken props no damage to the CS6. The ESC for #4 died from what I can tell after the fact and once the motor stopped it just rolled to the rear and fell out of the sky. Don't know if it might have stayed in the air if there had been more altitude for it to try and recover, most likely not.

Parts for the AV 130 were supposed to be here at 10:30 AM this morning but Fedex screwed up and dropped the ball, now they won't be here until Monday, I hope. I was furious when I found out as I paid about 2/3 the value of the parts in shipping costs to get them here today and all I got was jerked around by Fedex via email support trying to find out what was going on . Finally called them and got the real story and a "sorry" when I asked about getting a refund on the shipping cost since they didn't get it here in time, I'll be sure to use UPS as much as possible after that...

Ken

 

[GGoodrum]

I guess you did miss it, New Years day not quite 6 minutes into a flight as I was flying back to the takeoff point and descending it did a backflip onto it's side then proceeded to roll and pogo off the AV130/Nex 5N and wind up more or less right side up again. Bent the H**l out of the AV130 and busted the NEX, but other than a couple broken props no damage to the CS6. The ESC for #4 died from what I can tell after the fact and once the motor stopped it just rolled to the rear and fell out of the sky. Don't know if it might have stayed in the air if there had been more altitude for it to try and recover, most likely not.

Parts for the AV 130 were supposed to be here at 10:30 AM this morning but Fedex screwed up and dropped the ball, now they won't be here until Monday, I hope. I was furious when I found out as I paid about 2/3 the value of the parts in shipping costs to get them here today and all I got was jerked around by Fedex via email support trying to find out what was going on . Finally called them and got the real story and a "sorry" when I asked about getting a refund on the shipping cost since they didn't get it here in time, I'll be sure to use UPS as much as possible after that...

Ken

Wow, I did miss that. Bummer. :dread: Do you know what caused the #4 ESC to fail? I've never even heard of one of these failing before. I do know that the WK-M does not try to compensate if an ESC/motor quits. I still don't know why, but I've had two instances now, where my #1 motor has stopped, and it simply rolls over in that direction. Once it gets to 70 degrees, it shuts off all the motors. My first incident was right after arming, when I was trying to lift off. In this case, it just rolled over in the grass. The only damage was one broken prop. The second incident, shown below, happened two minutes into the flight. I too was trying to descend at the time, when the same #1 motor quit. it rolled over and took off in that direction. Again, as soon as it reached 70 degrees of roll, it cut power to all motors, and dropped from about 50-60 feet.

I had quite a bit of damage (two broken arms, cracked lower plate and five broken props...) and I'm just today going to finish getting it back together. I'm not sure what the heck to do about the #1 ESC/motor. I checked all the connections and they are all solid. I thought about moving ESCs around, to see if the problem follows, but I really don't want to suffer through another crash. :black_eyed: I have two more of these ESCs, leftover from my retired X8, so I'll probably just replace the one currently in the M1 position.

One thing that nags at me is that the 70-degree shutdown is only supposed to happen when the throttle is also under 10%, and while I was trying to descend at the time, I don't think the throttle was down that low. But clearly, the shutoff happens, and it drops like a rock. Not sure what this means.

-- Gary