Every so often in the world of multirotors, a company comes along with a game changing idea that make’s you think “why wasn’t this done before!?” The new POPO (Pop On, Pop Off) motors by Lumenier are exactly this type of revolutionary product. Just like the advent of smart audio, Lua Script control, or FC based OSD. The new POPO system addresses one of the most mundane interactions we regularly make with our machines and makes it exponentially quicker and easier.[vc_single_image image=”2289″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]You might be wondering so what is POPO? Well, to be honest you probably aren’t. Unless you have been living under a rock, you have most likely heard of Lumenier’s new propeller fastening system for their motors. The new system replaces the traditional, ‘easy to lose, and time consuming to fit’ locknuts used to hold the propellers to the motors. It replaces them with a simple push button that securely locks and quickly releases the propellers, requiring no tools to do so.
I think everyone that has spent significant time dealing with multirotors has at one point, or another, avoided removing props due to the hassle of having to get out the 8mm wrench and fight with undoing the locknuts. I know I’m guilty of hooking the quad up to the PC to adjust settings and leaving the props on, simply because I’m dead tired, trying to sort out an issue and it’s early in the morning on the night before a flying day. Now I won’t.[/vc_column_text][vc_single_image image=”2292″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]
The Motors
Currently the POPO motors are offered in just one version, a very nice, blue/black bottomless 2206-9 2450KV. 2206 is pretty much the standard size of multirotor motors these days, and 2450KV is smack bang in the middle as far as KV offerings go, making it a great motor for an all round flyer or freestyle machine. The machining of the motor both on the base and bell is top notch and you can tell right out of the box that they are a quality piece of kit. The windings are the multistrand type and the magnets used a N52sh with a nice and tight airgap. They are flat, not arc magnets though, which surprised me a bit. The motor screws are all 16mm PCD so as long as your frame is drilled for 16mm PCD or has slotted screw holes they will mount up fine. The motors use C-clips to hold the bell in place, but the C-clip is slightly recessed into the base of the motor so you wont have any issues with clips fouling on the carbon when mounted to the arm of your machine.[/vc_column_text][vc_single_image image=”2295″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]
The POPO System
The secret to the POPO motors is the repurposed ball lock retention system. I say repurposed, because ball lock retention has been around for decades and is much more common than you might think (remember those old push to release keyrings? They were ball lock), but ball lock retention is usually only used in axial retention situations (two pieces trying to pull apart) not rotational locking. Lumenier have designed a propeller hub that takes advantage of the axial retention of the ball lock to hold the propeller onto the motor, then uses the small ball bearings themselves to fit into special moulded grooves in the hub to prevent the propeller spinning on the shaft.
When I first saw the system I was sceptical, the small points of contact provided by the ball bearings doesn’t seem to be very much to hold the propeller. But, when you consider when a normal nut is used, the prop is only gripped on the sides to prevent it from spinning, it’s easy to see that the same, if not more force can be applied by the bearings in the grooves to keep the propeller from spinning.[/vc_column_text][vc_single_image image=”2298″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]A quick way to visualise this is to grab an old prop and a pair of pliers or multigrips. First grab the top and bottom of the prop hub with the pliers and try rotating the propeller with your other hand, you will find that even with a strong grip on the pliers the prop will rotate easily. Now grab the sides of the prop with the pliers and try rotate the prop, you will see that even with a light grip, the prop is almost impossible to rotate. This is indicative of the difference between a usual Nut fastening and the new POPO system. Even though the ball bearings holding the prop are small, they will take a lot of force before they slip.[/vc_column_text][vc_column_text]
My Experience
The motors come boxed in the typical way, fairly plain box with SKU details on the side. Motor, Locknut, and mounting screws on the inside. First inspection showed them to be very nicely made. They look light, but durable.
I decided to put these straight onto my Remix frame but noticed two things. The motor wires were too short at only 100mm (the Remix really is the worst case scenario with a 4in1 combined with having to wrap the motor wires around the arms) and the supplied screws were only 4mm long so didn’t even make it through the arms. I have talked with Lumenier and they have informed me that both these points have been addressed and motors are being sent out with the correct hardware and slightly longer wires. (My motors are technically a pre-release sample)[/vc_column_text][vc_single_image image=”2300″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]To get around the short wires, I decided to rewire the motors (I hate untidy extensions!) this was pretty straightforward but did take quite a while. I found some suitable screws and bolted them up with the obligatory threadlocker.[/vc_column_text][vc_row_inner][vc_column_inner width=”1/3″][vc_single_image image=”2302″ img_size=”full” alignment=”center” onclick=”link_image”][/vc_column_inner][vc_column_inner width=”1/3″][vc_single_image image=”2304″ img_size=”full” alignment=”center” onclick=”link_image”][/vc_column_inner][vc_column_inner width=”1/3″][vc_single_image image=”2305″ img_size=”full” alignment=”center” onclick=”link_image”][/vc_column_inner][/vc_row_inner][vc_single_image image=”2306″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]Along with the motors I got a few sets of both Lumeniers ‘Butter Cutter’ and ‘Gatebreaker’ props with the POPO compatible hubs, of course I ripped open a fresh pack and had a play with the system! This is where I came across the first issue, for some reason the Butter Cutter props use concentric hub rings which need to be installed before the prop is used.
These are small and fiddly and for me it kind of defeated the purpose of the quick release system. There’s not much point being able to install and remove your props from the motors really quickly, if you then have to spend a couple minutes fiddling around trying to cleanly break the hub rings out of the sprue they come on and install them into the props, before you can put the props on the motors.
Considering that Multirotor motor shafts are well standardised, and moulding technology is more than competent of forming accurate and well centred hubs on the propellers (as evidenced by the Gatebreaker props), I see no reason why they have chosen to use centring rings on the Butter Cutter props, a secondary negative side effect is the sharp lower edge of the hub rings makes it difficult to get the prop past the bearings of the ball lock. I used the tip of a pair of scissors to very slightly ream the lower edge of the hub ring and the prop went on much easier.
The actual installing of the props is very easy, just push the prop on while depressing the button on the shaft and prop slips down. A bit of firm pressure while twisting the prop, lines up the locking grooves and the button on the shaft pops back up giving a visual indicator that the prop is securely retained![/vc_column_text][vc_row_inner][vc_column_inner width=”1/3″][vc_single_image image=”2309″ img_size=”full” alignment=”center” onclick=”link_image”][/vc_column_inner][vc_column_inner width=”1/3″][vc_single_image image=”2310″ img_size=”full” alignment=”center” onclick=”link_image”][/vc_column_inner][vc_column_inner width=”1/3″][vc_single_image image=”2311″ img_size=”full” alignment=”center” onclick=”link_image”][/vc_column_inner][/vc_row_inner][vc_column_text]
The Flight
For the maiden of the motors I took the Remix to a spot that I like to go to, where I know I won’t have to be dodging dog walkers and other park users, there was quite a bit of wind but it wasn’t blowing a gale. There’s a heap of trees to climb over and play around with, so perfect for doing some freestyle.
As expected the motors are great for freestyle. They have heaps of grunt both down low and still have plenty of power up top. The 2206-9 (I have no idea what the 9 is for, maybe length of the arms on the stator?) 2450kv is a pretty common across the Lumenier range of motors so I won’t go into details of performance.
One thing worth mentioning is the little rubber gasket/pressure pad on the top of the motor, it simply sits around the shaft and is not in any way fastened to the motor. You don’t get a spare in the box, and it does sometimes have a tendency to stick to the prop when you remove it. I am worried that I may lose it when switching props or if I actually manage to break/knock one off the shaft.
The gasket feels a little bit like an afterthought seeing how well the rest of the system is designed, it would be nice to see it fastened to the motor in some way. I understand cost is probably a big factor in what is already a much more complicated motor system. Even if the gasket was simply cut with some double sided adhesive on one side that could adhere to the motor bell, that would eliminate the risk of losing it in the field.
I started out with a set of the Skitzo Butter Cutters and they felt great, I immediately felt comfortable throwing myself over and under the trees. Everything felt smooth and the grip on the quad was good even with the weight of the HD cam, they felt quite similar to the HQ 5×4.3×3 V1S PC that has been my go to prop for the last 6 months or so.[/vc_column_text][vc_single_image image=”2313″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]After getting a bit cocky, I faceplanted into a tree and bent both the front props. I bent them back, and they returned to their original shape well, though they did feel like they weakened a little where the plastic bent and there was some deformation visible in the plastic. Usually I would have kept flying them (I don’t usually record HD when flying, so jello from slightly bent props isn’t usually an issue) but since I was there to test the POPO system I took the chance to give it a blast in the field. I Switched out the Skitzo’s for some Wild Willy butter cutters and doing this in the field confirmed my hate for hub rings…. The POPO mechanism however, was excellent.
It’s so nice not having to dig out my tools and wrestle with the lock nuts. Except for the sharp edge of the hub ring being a bit stubborn, the prop swap was quick and painless and I was back in the air again.[/vc_column_text][vc_single_image image=”2315″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]I repeated the process flying out another couple of batteries, clipped a few trees with pace and had no issues with the props staying in place. After a few decent crashes the props were a bit dinged up and since I had the HD running I decided to switch the props out again and give the Gate Breakers a go.
Switching to the Gate breakers is when I got to experience the POPO system the way it should be! The Gate Breakers are a single piece moulded hub propeller and even have a taper leading into the shaft hole, so you simply tear open the bag and clip the props into place. They slide over the locking system easily with the help of that taper, and with a bit of pressure (quite a bit of pressure) and a twist, the button on the top of shaft pops back up and you’re good to go again.
I found I like the Gate Breakers better than the butter cutters when carrying the HD around. I’ll be honest when I looked at the spec of the prop and that shape that is reminiscent of the infamous Racekraft 5051’s I honestly thought “RIP Batteries”. But, looking at the prop closer, the pitch is only super aggressive near the root of the blade, where the rotational speed is lowest. About 25% out from the root, the pitch reduces dramatically till there’s barely any pitch near the tip.[/vc_column_text][vc_single_image image=”2317″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]I can only assume that a lot of time and research has gone into the blade design, because it seems to work really well, I felt fast, and despite being quick and having a heap of fun throwing it over the trees and hitting gaps I got a decent amount of flight time out of my battery.
I remember seeing a video where Tommy Tabaija was giving his opinion of the props and mentioned how smooth they are, and I agree. I thought from Tommy’s video it was possibly because the props were heavy and just slow to respond giving a sense of smoothness, but after flying them they seem respond just fine, but they do feel very smooth.[/vc_column_text][vc_single_image image=”2318″ img_size=”full” alignment=”center” onclick=”link_image”][vc_column_text]I only had one mishap with the POPO system and that was a blade coming off the motor after hitting a section of tree at speed. It was a solid hit and POPO system or not, I was ending up on the ground. I would put money down that had I been flying my regular motors I would have had loose props to retighten at a minimum. As for how the prop came off, I can only assume that I managed to hit the shaft release button on a branch as I passed though, because I found the prop in the grass still in perfect condition. The hub was not damaged in anyway and I simply clipped it back on, straightened one of the other blades and carried on flying[/vc_column_text][vc_column_text]
Conclusion
Overall, I was really impressed with the whole system, the motors are smooth and powerful, the props work great with the motors, and the POPO system was really reliable. I love that I don’t have to worry about using tools to switch the props. My only gripe was the hub rings and that’s a pretty small factor. I’m looking forward to doing a whole heap more flying on these motors and just need to stock up on POPO props.
Lastly, I did find when I got home that a lot of my HD footage was filled with jello that looked like something was unbalanced despite the fresh motors and props. It wasn’t visible in the goggles and it was a windy day. I hadn’t done a lot of re-tuning prior to flying, however when I moved to the single piece Gate Breakers, the jello was gone. I need to do more testing to isolate the true cause of the jello but for now I will be going for the single piece props.
Pros
- Quick tool-less propeller changes!
- Very nicely made motors
- POPO shaft locking system works well and is reliable
- Props feel great in the air and are efficient
Cons
- I don’t really have any cons for the motors, I really like them. Knowing they are now packaged with longer wires and correct screws means I have nothing negative to say about them
- Hub Rings on the Butter Cutter props – A small but annoying feature that as a product designer I cannot see the point of. Removing the need for the hub rings is a simple ‘Metal Off’ tool modification. Unless I’m missing something and there’s actually a reason for them, I hope they are removed.
I hope you enjoyed the rather lengthy review, I’ve definitely enjoyed the POPO motors on the Remix frame, they seem like a great match and I look forward to getting out and flying them a heap more now that the weather is getting better and I can see the tree’s again!
Keep those props spinning, happy flying.
Waiting for the new version I heard about from KababFPV that have the button sunken in or flush so no accidental presses are possible.
this should be the future standard
I might consider this buying to upgrade my stock motors for my Vortex Pro 250! Seeing using a proprietary locking mechanism would let me only using Lumenier props
Can’t wait to try these out
It looks as these would hold up well to a crash. Good Job Lumenier!
My next build will have these.
If the price of this was cheaper, this would be taking over the hobby
Very Cool! The ability to quickly exchange props is a fantastic idea, and the Lumenier POPO motor system works very well. After many flights with these motors, I have only had a prop come off once or twice after crashing inverted. I would purchase these motors again.
As POPO props come more readily avail. I plan to try out some POPOs : )
Xlite entry
Now that we are finally getting some prop options I think it may be time to give these a try. Such a Quality of Life improvement for our hobby.
Great concept borrow from quick connect hoses.