DJI's New E800 Locking Props

[HunterSK]

A few days ago I learnt about this from RCGroups, and was curious why it wasn’t brought up earlier on this forum and DJI’s forum. So I’m putting this out.

The Inspire 1 uses DJI’s E800 motors, and DJI are starting to sell the motors for people building their own multirotors.

In the E800 manual, the motor bell and propellors have been designed to be self-locking (instead of ‘self-tightening’ which we know is bull).

http://download.dji-innovations.com/downloads/e800/en/E800_User_Manual_v1.0_en.pdf

This is the photo from the manual:

Pure speculation on my part, but I think this is a much better long-term solution to slapping on plastic locks (which can get lost or possibily come off due to wear and damage of the plastic material).

I think this will be on a future Inspire 1 revision at some point.

If I was DJI, I would do the following additional to shipping propellor locks quickly so that customers can use their exisiting self-tightening props:

1. Ship customers a kit consisting of the motor mount, screws and four self-locking propellors (DJI model 1345s).
2. Offer to do the modification if the customer bring back the Inspire to retailer, distributor or DJI themselves.
3. If and when this new motor mount is implemented on the Inspire, clearly label the new model number so that future customers can identify them.

I think the prop locks were a way for DJI to overcome the issue cheaply and quickly, but really they should really aim for a long-term solution and this locking prop design is a much better long-term solution.

Going a step further will earn trust from their prospective customers.

 

[HunterSK]

Hi Joola,

Good point.

Based on DJI's own manual, the motors are also compatible with the self-tightening props if the motor mounts are removed.

From the E800 manual:

From this information, I think existing motors can be modified by simply installing the motor mount.

 

[Tahoe Ed]

Thanks for sharing this information here as well. It's pretty surprising to see this come out so soon after prop-gate.

I agree with your assessment of what DJI should do but I'm also not certain if the threaded spindle for out self tightening props would work with these locking props even if we add their mount. It might require the entire motor be replaced for them to work.

I have several sets coming to test. You just need to screw the lock on the top of the motor bell and then screw on the prop.

 

[HunterSK]

I'm hoping we'll be able to update the ESCs to enable active braking with these new props as well.

Motor braking is already activated on the Inspire 1, that's why the prop locks are necessary for the low-probability event of the prop coming off.

 

[Thomas]

DJI learned of this flaw (and made permanent fix for) at the expense of early adaptors (customers).
Very few customers experienced their props falling off while all customers were told not to fly until locks are received.
DJI should do the right thing by providing the permanent fix to existing customers and that would be an example of a GREAT customer service. We'll just have to wait and see on that.

 

[HunterSK]

I hadn't heard or seen this confirmed anywhere. I know many users were saying active braking caused the props to fly off (versus just a rapid slowing of the motors combined with the larger rotational inertia of bigger props). I checked the manual and couldn't find any DJI support person saying the motors have active braking enabled. When I throttle down, my props don't stop immediately as if they would with active breaking.

Of course I could have missed it somewhere. It's not possible to read every thread of every forum.

You'll find a statement here from a DJI employee:

http://www.rcgroups.com/forums/showpost.php?p=30493871&postcount=3508&lang=en

"E800 and inspire use close loop ESC and apply active brake on the motor. If you did not screw the prop in tight as it required, the prop may fly off in some circumstances."