Just curious who among you have tried 816’s and what your experience has been in comparison to other sizes. I know @chime13 and @Bobnova have spoken highly of their power and weight savings. Are we all accidentally ignoring the best possible motor size?
Whatchu say?!?! I never knew this size existed. I must find some.
They are obscure and are 8mm - not 8.5mm. They weigh significantly less than 8.5x20 and may possibly have a power to weight ratio that exceeds the 20 mm big brother. From what I hear they are a replacement part for certain larger geared toy quads. Geared quad replacement motors are most often high kv motors.
Lately I’ve been on an extreme weight reduction mission. Printing lighter frames and even flying my 8.5mm build on the 260mah battery that came with my e011. Surprisingly I’m getting almost 3 min flight time. Of course it’s hard for a 260 to keep up with the demands of 8.5mm - but punch performance is on par with 500mah due to the reduced weight … and handling is better because flight weight is 10 grams less. Anyway - these experiences lead my attention towards the 816 size for even more weight savings. @Bobnova reports running 66mm props on his. I will try to dig up an old flight video now for a refresher on their performance from when he tested.
I’ve seen the same results with a 260 on my 8mm builds. I did see some 817s replacements listed for a Syma quad. I may order some to try. Ill just have to add a later of heat shrink to the motors so they fit the rubber grommets. Do you know if the motor shaft is the same diameter as most 8.5mm brushed motors?
Syma x5uw if I recall correctly, NOT the x5c, which uses 7mm.
This weekend I plan to print a frame and try them out again, will report!
Here are the ones I found. They say they are 817.
I dont know its a mystery if you click the link it says 816 but if you choose the motors from whats available they are listed as 817.
When I get home today I’ll measure mine and figure out which syma they came from.
Might be the u/uw is the 0720 motors I like and c/cw is 0816.
In any event, they go pretty good, both of them!
260 lipo with an 8.5mm motor? I tried to fly my brushed racerstar 8.5mm motor with 240mah 1s lipo but ended up with a super hot, soft battery. After this experience, I’m afraid to test my e011 and Bwhoop lipo with my 39gram, 8.5mm motor setup.
Oh yeah, mine are syma x5c, they work great on e011 batteries and afunta props. 8x16mm.
Meant to post some video, maybe I’ll remember tomorrow.
Mine did ok on hubsan replacement 8.5mm. Warm but not hot. I just ordered a 6 pack for this purpose. Curious to see how long before I kill them. Either way, it’s worth it to me to shave the weight. I’ll do some comparisons to the vier more traditional sized batteries. I’m sure they deliver more current … but they have to haul more weight too. It may be a wash as far as punch goes. In that case I’ll take the lighter craft over the longer flight time.
Ok… I just flew the 816’s line of sight. Build was 24 grams dry with props. Fastest configuration was the 66mm kingkongs. Fastest vertical punch out was with the e011 45c batteries but a tattu 600mah wasn’t far behind. The 816 build was about 7 grams lighter on the scale. That’s huge!
I also put this head to head with an 8.5mm build using exactly the same props, frame, and battery.
It DESTROYED the 8.5mm. Rpms sounded a little bit higher … a few thousand rpm or so… but the weight savings coupled with a little faster rpm was unmistakably superior.
This leads me to call on @Benedikt… please oh chief scientist sir… shed your micro motor wisdom upon me!!! If you can get 816’s built with the same rpm as dark editions … and save weight with the smaller can… wouldn’t this be worth looking into? Is there a reason 816 has not become popular in a quality aftermarket high rpm option?
I accidentally discovered the 0816s due to an incorrect order back in June and thank God I did! Definitely found that the 20% weight savings over 8520s is a major performance gain. I do get the best performance out of 60mm props and consistently get 3+ minutes of crazy flying with 500mah lipos. I’m waiting for my Turnigy 600mah lipos. I think the higher output Turnigys will kick it up a notch.
IMHO - A MMW treatment of these 0816s would be a new level of performance in micro brushed quads.
Same story with @Bobnova… an accidental order when going after 720 syma motors. I still remember his pleasant surprise upon installing them. Well I’m hooked now. If we could only get @Benedikt to chime in on his thoughts with this curious size… or better yet to thrust test them for us head to head against some 8.5’s and give us the behind the scenes info on their availability/kv data.
I have a theory to offer somewhat inspired by @JG101. Could our batteries be giving us a “speed limit” that both 816 and 0820 hit. Maybe given constant voltage - the larger 8.5 would out perform. But given real world current and voltage supply from a 1s battery… both motors hit the same limit and the lighter ones win from weight savings? ?
Analogy : the faucet only flows 20ml of water. Should I carry it in a cup or a bucket.
I think: “Battery speed limit” would depend on the discharge rate of the battery and not so much the storage capability. For our purposes - " Sub 110mm 1s micro brushed fpv quads" I think the 816s are optimal as far as efficiency is concerned. Basically, same performance as 8520s but 20% lighter and 4mm shorter has to translate into better performance. In racing, you only need to carry the necessary fuel (weight) to make it to the end of the race. I don’t think we can get a better performance bump than shedding 4grams.
I’d love to see some mmw 8x16mm motors, I bet they’d be flat nuts. Like the 7x16!
I have some 8x16 motors. A few came out of a Syma, then some of another geared quad that someone brought me. I was not so impressed with performance.
7.0x20 motors and 8.0x20mm motors were already close enough together in performance, so I didnt see the need to add another step to the portfolio at this point.
Also, the use in RTF quads is so limited that I dont expect much demand from people wanting to fix these quads, especially since you usually can modify the motor mounts and fit 8x20mm motors.
Adding a new motor to the list will cost me one or two days of work and a few thousand dollars initial investment.
It’s a bit hard to justify right now, but if I manage to sneak in a small sample batch, I will let you know here.
What I am considering though, is a 7x16 variant with 1mm shaft
I’d love to see a thrust test on one you have laying around with 66mm props if you feel foggy … or feel like proving the 8.5’s are fast enough to justify the weight spread
Might make a neat youtube video