Are my props too big?

[iceman]

I need some help with general stability, so, what I have is Droidworkx AD6 HL 360 frame and Photohigher AV200 powered by Pulso U28s swinging APC 13x6.5 props and DJI WKM FC. The bird flies but I can’t seem to get good stable flight, dialled in attitude hold until oscillation occurred and dialled that setting back 20, set pitch and roll to 150 and all other are 100. The flight is somewhat generally wobbly especially when roll or yaw commands are given. Most flights have been in light winds less than 10mph and one day with no wind but still can’t get it stable. Are my props too big for DJI? I read somewhere that DJI prefers smaller props spinning faster, I have noticed when looking at video footage from GO Pro (when I hear the props spinning faster) it looks more stable. Any help or advice much appreciated.

 

[Gunter]

I had loads of wobble with my 13" wooden props. I have gone down to 12" plastic and it's made a huge difference. I am just waiting for some 11" thin Graupners to arrive which I'm sure will be even better. Ken has tried the smaller props with very good results.


Regards,

Gunter.
Sent from my iPhone using Tapatalk

 

[iceman]

So the question now would be 12" or 11", are there any pre balanced and would I still get enough thrust with 11" on my HL hexa?

 

[Gunter]

So the question now would be 12" or 11", are there any pre balanced and would I still get enough thrust with 11" on my HL hexa?

What weight is your hexa?

What I have done is to buy a set of cheap props and try them out. Get yourself a cheap set of 12" and 11" epp props and see which ones work best. Then when you find the ideal size, get a decent set and fit those.

Every setup is different, so difficult for anyone to suggest the ideal props for your heli.

The cheaper ones probably won't be balanced, but I did that myself by applying a bit of sandpaper on the heavier blades or putting a bit of epoxy on the underside of the lighter blades. Not ideal, but good enough for testing and good blat around the field. You can also keep them afterwards as a backup.

Good luck!

Gunter.

 

[iceman]

Total takeoff weight Inc payload is 5kg, good idea using cheap props for test. As long as I'm on the right track to improving stability with something smaller than 13"

 

[Gunter]

Total takeoff weight Inc payload is 5kg, good idea using cheap props for test. As long as I'm on the right track to improving stability with something smaller than 13"

My takeoff weight is 4kg with 12" props at the moment and it's fine. I'll let you know what the 11" props are like next week, after they arrive

Gunter.

 

[iceman]

Thanks Gunter, that would be great, keep me posted on 11" can I ask where you get your props from and are graupners factory balanced?

 

[Gunter]

Thanks Gunter, that would be great, keep me posted on 11" can I ask where you get your props from and are graupners factory balanced?

Apparently they are balanced in the factory. I have never used them before, but they look the part A lot of peeps use them, so I think they should be good.

I get them from HERE

Gunter.

 

[Gunter]

Thanks Gunter, that would be great, keep me posted on 11" can I ask where you get your props from and are graupners factory balanced?

Oh, just remember to get the inserts if your shafts are smaller than 8mm. They don't supply the inserts with the props.

 

[Droider]

Which APC props are u using?

Think RTryder is using the APC electro 12x6 on his CS6

Search RTRyders posts. He went into great detail on how he set up his hexa..If I can find the post Ill link it

Dave

 

[iceman]

Thanks dave, I did try to find his post as it was said the he was having great sucess with prop size but couldn't spot it.

 

[Macsgrafs]

I use APCE 12 x 6 props on my SJ8, flies really nice.

Ross

 

[Droider]

Aye Up Iceman

Check out this

http://www.multirotorforums.com/showthread.php?1396-CineStar-6-WKM-build

 

[iceman]

Thanks Dave, that's the info I was looking for. Makes sense that the FC can make quicker adjustments to rotor speed if the prop/motor combo are not too big for the application.

 

[Gunter]

I fitted my 11x5 Graupner Eprops this weekend and it make another huge difference! I took a guess at setting my gains at about 150%, and it just flew lovely! The AUW is around the 4KG mark on 6 rotors.

You can see how smooth it is in the video I did testing the new firmware. There are a couple of wobbles here and there, but that is mainly down to wind and not really taking note of flying very smoothly!

 

[iceman]

I fitted my 11x5 Graupner Eprops this weekend and it make another huge difference! I took a guess at setting my gains at about 150%, and it just flew lovely!

This is just what I wanted to hear, my Graupner 11x5 Eprops came last week but I ordered the wrong size step down inners, got the right ones on order now and can't wait to get fit them and give it a try. I did get some flights in today and got things better with my 13x6.5 props but not to the standard I need for video, it dit get better when I added extra weight. Gunter, did the Graupner 11x5 need balancing or where they factory ready?

 

[Gunter]

This is just what I wanted to hear, my Graupner 11x5 Eprops came last week but I ordered the wrong size step down inners, got the right ones on order now and can't wait to get fit them and give it a try. I did get some flights in today and got things better with my 13x6.5 props but not to the standard I need for video, it dit get better when I added extra weight. Gunter, did the Graupner 11x5 need balancing or where they factory ready?

I checked them all beforehand and they were all **** on. Also, the aerial footage on the video above seemed vibration free - TBH I didn't check that closely, but it seems okay. That was done with the gopro hard mounted directly to the front boom!

Gunter.

 

[iceman]

Thanks Gunter, your video looks good, very stable even the hard mounted footage. I just can't get my Hexa that stable, the AV200 gimbal is working real hard to keep up. Can't wait to try 11" props. I know it is capable of good steady flight but just can't dial it in with 13" props, there always seems to be some wobble especially when I yaw.

 

[Gunter]

I expect I might well need to go to 12 " when I add a bit of weight to get more lift, but she flies lovely at 4kg.

One thing about the Graupners, they are very stiff and the edges very sharp. I dare say it would cut your finger to the bone if it caught you at full throttle!!


Regards,

Gunter.
Sent from my iPhone using Tapatalk

 

[iceman]

One thing about the Graupners, they are very stiff and the edges very sharp

Is that why the instructions that came with the props tell you not to let them dry out? I think I will keep the hexa in the bath tub, I don't want dry props!