WKM on SJ6 teething issues

[139 jockey]

When I first started flying my sj6 I got the pitch/roll/yaw gains right up to 250% and it flew well. But with a pay load on it ( Cannon 550d on AV200 AUW now 7.8 KG's) I found it way to twitchy. I have ended up with the gains right back at the defaut 100 to get rid of the twitch. Is this normal with other peoples heavy hexa's ?

With the pitch, roll,yaw gains at 100 now it is reasonably stable, reasonable video with no jello.

I am running 5s with 14 inch props and wondering if I would get a better stability if I went to 6s with slightly smaller props?


I have been considering this from a battery endurance point of view as well. At the moment I am pulling about 36 amps in hover ( I am lucky enough to have a good clamp meter at work so I can check ) with 2x wild scorpion 5500mah, giving me about 9.5 min. flight time. (I have the low battery second level warning set to 16.8v, is that about what other 5 s users run down to?)

So I am looking at 2 options, either getting some 8000mah 5s ( I simulated the extra weight on the A/C today and it pulled about 41 amps ) hence giving me a conservative extra 2 minuites of flight time, or going to some 6000mah 6s with smaller props. Both batteries weigh about the same, around 930 grams for turnigy nano techs. It would be simpler for me to stay 5s so I can use my current batteries but I am not covinced that is the best combination.If any one has tried these combinations for batt/props with the WKM I would really appreciate some advise as to the best way to go.

Rick.

 

[BorisS]

Hi Rick,

flying the CS 8 with arround 5.5 KG fully loaded with a 6s 8000 mAh or 1 or 2 5s 5000 mAh. None of the bigger props 13 or 14 inch have given me good results with the WKM setup. My best choice up to know were 12 x 3.8 CF props 11 grams weight. In general in my eyes all these 14 inch props if XOar or APC are to heavy and also reduce the RPM which is important for WKM to reach some stability. Before you start buying Lipos i would give smaller props a chance. If you dont want to step into the expensive 12 3.8 Cf props right from the start try some 11 x 5 graupners just to see if smaller props do it for you !

Do an ecalc.ch before so see if the 11 x 5 dont run you into trouble.

Boris

 

[Siteline]

Hi Rick,

flying the CS 8 with arround 5.5 KG fully loaded with a 6s 8000 mAh or 1 or 2 5s 5000 mAh. None of the bigger props 13 or 14 inch have given me good results with the WKM setup. My best choice up to know were 12 x 3.8 CF props 11 grams weight. In general in my eyes all these 14 inch props if XOar or APC are to heavy and also reduce the RPM which is important for WKM to reach some stability. Before you start buying Lipos i would give smaller props a chance. If you dont want to step into the expensive 12 3.8 Cf props right from the start try some 11 x 5 graupners just to see if smaller props do it for you !

Do an ecalc.ch before so see if the 11 x 5 dont run you into trouble

Boris

Hi Boris.
I'm hoping you could share a screen shot of your e-calc. We are missing some information and I don't really know where to find it? We are getting requests to put heavier loads on our crafts and I want to make sure I don't cause any problems by doing it.

 

[BorisS]

Hi Site,

Sorry everything I wanted to reply to you guys I got distracted. Will get back to today !

Boris

 

[139 jockey]

Hi Rick,

flying the CS 8 with arround 5.5 KG fully loaded with a 6s 8000 mAh or 1 or 2 5s 5000 mAh. None of the bigger props 13 or 14 inch have given me good results with the WKM setup. My best choice up to know were 12 x 3.8 CF props 11 grams weight. In general in my eyes all these 14 inch props if XOar or APC are to heavy and also reduce the RPM which is important for WKM to reach some stability. Before you start buying Lipos i would give smaller props a chance. If you dont want to step into the expensive 12 3.8 Cf props right from the start try some 11 x 5 graupners just to see if smaller props do it for you !

Do an ecalc.ch before so see if the 11 x 5 dont run you into trouble.

Boris

Hi Boris,

Thanks for the link to the ecalc.ch. Great tool. I put in my current set up and it told me that I would be using 75 amps but my clamp meter tells me only 36 amps in the hover? I may have got something wrong with the clamp meter though. I hope I was on both the positive leeds.

Any way, the calcs look bad for the 11x5s. It says it wont even hover. It looks like the smallest prop I can run is 12x7 but even then I need to go to 6s to make it work.

In your experence is it the weight/inertia of the props that make the difference to the speed that they can react at hence the additional stability, or are their other aerdynamic factor coming in to play such as disc loading etc? I am running Xoar 14x7 at the moment and as you say they are very heavy @ 30 grams.

It looks like 12x7 with 6s might be an option for me but it could be an expensive experiment, would be great to find out what other heavy hexa users have discovered if they are willing to share.

Thanks,

Rick.

 

[BorisS]

Hi Boris.
I'm hoping you could share a screen shot of your e-calc. We are missing some information and I don't really know where to find it? We are getting requests to put heavier loads on our crafts and I want to make sure I don't cause any problems by doing it.

I sent an email give me more info !

Boris