Product Review ** DJI 1552 Folding Propeller

[Peterev]

I apologise for resurrecting this topic but having just finished a Sky Hero Spyder 700 (T-Motor U5 - X8) I am currently using T-Motor 15" carbon one piece props but would love the convenience of folding props. I was contemplating KDE's carbon folding props but I can't justify the £400 for them and the adapters which is how I ended up here..

My problem or potential problem is that I only have a 15mm clearance between the front top prop ends and the canopy. That 15mm is in both directions, sideways and vertically (the prop ends run across the top of the canopy by 15mm). Clearly sideways is fine but any downwards flex vertically would be potentially disastrous. Logic tells me that the largest flex would be upwards taking the prop ends away from the canopy but if you have opinion about how flexible the 1552s are, that would be much appreciated.

Thanks,

Peter.

 

[econfly]

I don't know for sure, but I really doubt that the prop will flex that much in flight.

 

[Peterev]

Thanks.. Did you have any misgivings about the DJI adapters? KDE used theirs with the 1552s here:

 

[Peterev]

And this is my 5th flight with the Spyder using TM one piece props and third tune on a Marcia gimbal, getting there:

 

[econfly]

Thanks.. Did you have any misgivings about the DJI adapters? KDE used theirs with the 1552s here:

The DJI adaptors are fine. KDE makes a nice version too. The main thing is confirming one or both will fit your motors.

 

[Peterev]

Many thanks, much appreciated..

 

[Peterev]

I decided to splash out on the KDEs in the end, it's amazing how much more portable they make it.. First flight later, will be interesting to compare the logs after for vibration and current draw.

 

[Mediakopter.no]

It would be really interesting to se å comparison between the folding KDE's and the standard T-motor CF props.

 

[Peterev]

It would be really interesting to se å comparison between the folding KDE's and the standard T-motor CF props.

I have an initial comparison between these two types of prop which indicate that the KDEs produce more vibrations that the T Motor CF props and draw very similar current at hover but I am waiting for a response to this from KDE as both those results are contrary to what I was told to expect. I will caveat that by saying that I had issues setting the prop bolts to the correct torque and despite spending another $75 on a torque driver, there was no consistency between the bolts, 0.35N-m would bind one blade yet the same torque on another blade would see it move relatively smoothly.

So I have adjusted the props back such that each prop requires a similar amount of force to move them and made that force slightly more than with the initial flights last weekend:

I have the flight video but it was not as good/smooth as the previous flight with TM props.

I would also add that, despite claims, some of the T Motor CF props do need balancing, 3 of my 8 were out of hub balance which I corrected with epoxy. T Motor did tell me that hub balance isn't important, which I thought to be a very strange position to take.

So to sum up my experience so far would be to say that I am disappointed with the KDEs, the vibration levels are certainly within the parameters demanded by Pixhawk but, at the moment, worse than the TM props. Weather permitting, I will try another flight later and hope that tightening the hub bolts some will have further reduced the vibrations. The KDEs are exquisitely made, they make the craft so much easier to handle and transport which is a bonus but that was only part of the reasons why I purchased them.

(the top graph is the KDEs)

 

[Peterev]

By way of a brief update on this, KDE kindly agreed to check the props that I was using and resolve any issues with them but I believe that the UK distributor decided not to send them back so I'll never know whether these were as good as KDEs get or if there was a problem with them.
I am now trying a set of Zeal folding cf props and out of the box, they gave slightly more vibrations than the KDEs but having balanced them statically (so each blade weighed exactly the same as its opposite), they improved to the same vibration levels as the KDEs which considering they are around half the cost is great. As each prop bolt relies upon a small amount of tension caused by the top and bottom plates being held apart slightly more in the centre than at the prop, initially I tried using blue threadlock to make sure they didn't work themselves loose. I think that the prop bolts were still too tight but I didn't feel confident in loosening them any more so I have now converted the adapters such that each prop bolt now has a nyloc nut, as per the KDEs. So I have set them all looser and will try them again soon.
I now suspect that folding props won't ever be quite as efficient or smooth as a one piece prop but we shall see.

 

[Peterev]

Update and conclusion:

The Zeal props didn't get better than they had already performed by loosening the prop bolts some so my conclusion is that folding props by their very nature have a hard time matching one piece props, perhaps the mechanism involved is inherently liable to vibration. The Zeal props performed in my tests as well as the KDEs for half the cost.

I have now refitted the T Motor 15" one piece props with a set of quick release prop adapters after I read this post:

http://www.dronevibes.com/forums/th...screw-type-quick-release-prop-adaptors.22220/

The attached is the IMU log from a flight this evening which as you can see is much smoother than both sets of folding props.

 

[Peterev]

 

[_sOnGoKu_]

nice post! thanks

 

[Peterev]

Thanks..

Zeal props now for sale: http://www.ebay.co.uk/itm/232033969373