These 5" Motor Myths have been repeated time and again, but are any of them backed up by the real data? Support me on Patreon so I can spend more time working on FPV: / chris_rosser AOS Frames: www.aos-rc.com/
I'm sitting on the side of a windy old hill watching my scale asw28 flying overhead and learning about motors. Bardwell in my heart & Rosser in my head. ❤😎
You have no idea how much research I did for my first 5", and right this moment, you come around with the absolute perfect video for my questions. Thank you so much for your very high quality research, helpful as always.
Chris, this is amazing. Thanks for these tests. It always pissed me off when people say 2306 is more low end torque and more efficient lol. But I didn't have data to back it up.
But it absolutely is true for the way freestylers fly and the graph proves it. You need a higher throttle value with a 2306 to get the same thrust as a 2207. Freestylers need precision in the low end of the throttle and responsiveness in the top end. So 2306 will always provide more precision at low throttle and less responsiveness at high throttle when compared to 2207. I also remember a Rotor Riot episode where Vanny and Le Drib were able to identify the two motors in a blind test based on that same observation.
@@kandredfpv As Chris mentioned, if you want low end throttle control and resolution it's better to use the Throttle Expo in Betaflight. Which makes more sense and you can tune it more to your liking.
@@BowserMG absolutely agree, there is no question about that. The point I am making is the graph does show there is a difference in throttle resolution so it isn't accurate to say it's a myth.
Thanks for this timely info. Looking forward to your next videos. Now I know what size, just have to decide on kv for 5in 6s. Glad we have you here contributing in this field.
Better explained or better explained, a precise and concise approximation allowing me to open my mind to knowledge previously without any possibility of understanding. Thank you very much Dr.
Thought I left my comment but apparently not lol 😅 this video is definitely one of my favorites from you well done 👏 I am in the process of slowly changing out all my 2207 2750 kv motors I was using for 4s but have been using on 6s with lowering the motor output limit and this was nice to know for me I will be sticking with 2207 for my preferences and getting lower kv for better efficiency of consumed power on 6s. Thanks for these awesome videos Chris!
Well done, Chris. Some of my opinions have definitely changed thanks to your video. I'll still be running wider stators for their cooling performance (I live right on the equator) but it looks like I'll need to be getting 6s motors in the future
Thanks for doing these great technical analysis videos. I admit to having a few surprises in this one, though these were on details on which I did not have a strong opinion. On the other hand, thanks for quantifying one thing that I have understood and agreed with for a long - that running a higher Kv motor with a throttle limit is far from being equivalent to running the right Kv motor in the first place. There is a huge lack of understanding in our community about the effects and relationship between motor Kv and torque. Even our friend Bob Roogie is challenged in understanding this, though he does seem to be learning. :-) Looking forward to seeing more of your technical analysis videos...
Finally these myths about the differences between 2306 and 2207 on which marketing strategies are based have been busted, thanks Chris, you have publicly demonstrated that the difference all boils down to the difference in stator volume. Anyone interested in the world of FPV should watch this video🙏
Chris is kicking butt and taking names with content like this! One question- would the last topic of the vid remain as true if using Motor Output Limit instead of Throttle Limit?
Throttle limit doesn't prevent the PID controller applying full power to the motor. Output limit prevents PID controller applying full power. Output limit is the right setting for 4S motors on 6S. 👍
Awesome content Chris. I always felt like 2306’s were less powerful and you have confirmed it. They just make less thrust compared to a 2207. I’m recently a new convert back to 2207 2050kv from 2307 1950kv and I honestly don’t know why I went up to 2307. The 2207 flight characteristics is everything and more that I prefer.
where did buy a 2307 motor ? ive been chasing 2308 motors for my 6 inch rigs or years after the only ones i available stopped being made? wha are those 2307 and are they still available ?
This is a good test for showing us how they work in a controlled environment...however...we do not fly drones in controlled environments...also would like to see the done a gain but with larger stator difference 2207 vs 2507 for instance
Another great video, thanks mate. My only question is are you able to test torque under more dynamic conditions? For example with your ramp tests the motor/prop combination is sitting on the test bench but that only simulates take off or quick pops of the throttle, but not recovering from a big dive were the torque requirements would be far higher? Anyway, love your work 👍
I love how you scientifically break motors down at the end of the day.. a motor is a motor is a motor.. i was going to swap my motors on my BNF Nazgul Evoque F5x V2 because i thought 2306 would work better than the stock xing2 2207 1750kv for freestyle and just overall make my quad fly better if i got some expensive 2306 1750kv's maybe even the same ratings as the stock ones on the Nazgul just more expensive (eye candy ones) as i thought they would perform better but after seeing a load of your videos and a few others I have come to the conclusion that... A motor is a motor is a motor... I'm better off just sticking with the ones that iflight chose to put on the drone they made as it will have probably been made around them motors anyway so i probably wont find any better performing ones for it anyway lol. Anyway great video's keep them coming my friend!👌👍
Super!!!!! I’m so glad you did this testing!!!! Thank you sooo much for all your contributions to our hobby !!!! I have the GepRC Mark 4 HD DJI V2 vista nebula pro. The quad copter comes with 2306.5 motors. After watching your video I’m thinking I would rather have 2207’s. Basically what I got from this video is that. What do you think if you were going to build this frame from scratch you would put 2207’s on it?
@@ChrisRosser of course not. I have another five inch which is on 2207. I could just tell the difference when I flew the 2306.5 I feel like it would put me where I want on feel. Feel is very important to me so that I am comfortable while flying. Thank you so much for responding 👏 your the best 🙏🏻
@@ChrisRosser It’s also a lot of work for a small change I know that. I really didn’t relish the idea of removing four perfectly good 2306’s to put 2207’s on but I may do it in the end. Something small like this just gives me that edge feeling. You know that feeling where you think you’re invincible and you can do anything ? That feeling is very important to me. When I’m flying I like to feel like I have the edge. For some reason it gives me so much more confidence.
Just something to throw at this? The additional outboard weight on the 2306 vs the 2207, would it not act like more of a flywheel in flight, static bench tests don't account for airflow at speed. Every myth is just some misunderstood science, so the tale of 2306 feeling more torque could be right but just not scientifically proved yet. Lets say quad is descending and you are at say 20% throttle. The resistance of the prop on the air pushing back up from the descent would want to slow down the prop/motor. Would said 2306 not slightly keep the prop at better momentum compared to the 2207 that would need to apply a bit more power to keep the prop spinning at given speed? Or is that cancelled out ultimately by the increase in response of the 2207, or is that the reason why the 2207 is more responsive? This could also be where the tale of efficiency comes from? The heavier fly wheel effect takes less effort to keep spinning at same speed (Cruising). Kabab FPV even went as far as developing pancake style motors, which in practice have proven to be more effective on whoop style flyers which all have 1 thing in common, they tend to cruise at set throttles a lot.
The flywheel effect you speak of would not decrease the power to spin the motor at a certain RPM. We can see this from the torque vs RPM curve and also the thrust vs power curves. A motor with more MOI will take more power to accelerate/deccelerate. In my opinion this 2306 being more efficient myth comes from the fact that it is a smaller, less powerful motor so it draws fewer amps. What people didn't realise is that it also makes less thrust so it is not more efficient, just weaker.
I had a feeling we weren't getting something for nothing by running higher KV with a limit. It might still make sense to do it when transitioning to 6s from a lower voltage just so you don't have to buy all new motors, but it's good to know what the facts are.
😂 finally, someone did the proof of these "feeled" claims. since the beginning of having brushless motors we made stator volume decisions. (except pancakes with different pole numbers). then came the fpv scene and brought a bunch of useless motor variants to the table. some of the stator combinations are just a trend.
Well you answered that question about running 4s motors on 6s battery I have I bunch of 4s motors I wanted to use but I guess I could use them if Im waiting on a set of 6s motors or something thanks
Wow yesterday I was thinking about suggesting you making a video about 2400kv with motor output limit vs 1700kv at 6s battery voltage as you have the motor test bench.. this is really stumping.
In my experience, if you put a 2207 on a bad frame, it can deliver less power than a shorter motor due a higher motor producing more motor wobble due to its higher leverage on twisting the arm. This is perhaps where some of these myths come from. I think that maybe efficiency can only be tested in flight, not on the bench. Heavier flywheel effect motors can be more efficient due to the flywheel effect, this is maybe something that can't be tested on the bench.... Like flywheels in normal car clutches are heavier than racing flywheels for the very reason of efficiency.
@@ugpfpv361 I d'know, only a theory I heard... The breaking level of the ESC does depend on quite a few factors... And I think, in BF 4.3 we're getting some freewheel effect on reductions of throttle, not sure if that's global or a feature you turn on or off.
Fantastic testing, Chris! Really interesting results, thanks! 😃 I just subscribed!!! Stay safe there with your family! 🖖😊 BTW, I remember some people complaining about the quad "looking down" (for a lack of a better expression 😬) when you give zero throttle after a full throttle punch... But I believe it's a turning issue. Right?
Conclusions from there should be written in bold above every motor comparison article. Already had idea that main difference between 2306 and 2207/2208 is caused by KV difference and particularly due to lower KV for 2306 motors in historical comparisons. 4S motors being less efficient on 6S is nothing new. But because we are killing remains of our old 4S stock on 6S because no one want to buy them anymore and some of us think that throwing out working motors is bad idea, make it non-issue. Can you advance topic about throttle lowering for long range setups more? I see that it would be great way how to make all-rounder quad: flying freestyle on full throttle then switching to lower throttle profile for casual long range. This actually made me think what to do now with 2306 in my shelf...
interesting results, i wonder if the load/unload aspect of bench testing has any bearing on the outcomes, i'm still running xing e 2207 2750 kv,s , i dont do any wild thrashing freestyle so the voltage drop isnt a hufe issue for me, but i would like to see some tests of a 6s pack on the 2750kv's, running auw 690g.
Very interesting, great video and presentation! Question about the KV 'adjustment' using throttle limit: I feel the most likely reason someone would run 6s on 4s motors with a throttle limit would be to try out the voltage sag and efficiency benefits of 6s without having to buy a new set of motors. Did you also test those parameters with the same KV motor (2400KV) just using two different batteries (4s vs 6s)? Cheers
Very interesting video! I still have some good old 5" 2204 motors running. Maybe it would be a interesting video to compare how much the size effects flight performance since right now the motors get bigger and heavier. I am saving almost 80g compared to some of the recent 2505 motors or similar. But how much performance am I getting ? At some point bigger motors cannot be beneficial anymore on 5". Am I right?
@@ChrisRosser and some smaller for comparison would be cool :) I want to know if I need to upgrade my old, but perfectly fine 2204 on about 450g AUW. What do you think?
I've been flying rcinpower 2107+ 1980k for maybe a month after flying 2405 for a while then the fpvcycle imperials for a bit then some 2207s. At first I didn't know about 2107 it seemed weird to me (so is 2405 but I like weird shit who cares) but man oh man I have been loving them so much they are super responsive and I still get my same old 3-4 min flights I was getting on any the other motors I flew before and they seem pretty durable. I wouldn't mind seeing you test some of these strange size motors like mine, the 2505 t motors, maybe fpvcycle and any other odd ball 5-5.5 Inch motors we can find I'd love a video like that
What prop do you use? In my flying test I switch between F40 and F60 on my quad. I really saw difference and really enjoy 2304 motor with gemfan 5552 props on a ~650g quad. The feeling when turning st low speed in circle around trees was great. According to your test, This mean in blind test it would be really hard to see difference ?!
Do you have any ballpark estimates as to what the sample variance would be if you tested a batch of motors? For instance, actual-versus-advertised KV can vary not insubstantially from sample to sample.
The 2306 is only 9.2 grams/set lighter than than the 2207......So on a 600g 5" .....9.2g/600gx100 = 1.53% lighter........that's the difference of a short/long 12ga battery lead......or different battery mfg of the "same" mah capacity;-)
Hey, can you make a video to explain how Motor output Limit works. I'm not sure how ESCs work and if it Limits the output voltage to a motor or the amps. And I'd like to know if it might still have the advantage not having that much voltage sag running a 4S motor in 6s with MOL
Motor output limit just limits the max signal to the ESC which limits the max motor current. Running 4S motor on 6S is going to be 10% less efficient regardless of voltage sag.
I just had real live test but it was somewhat a little different. I put another brand new 2207 in the mix with 3 old 2207. The new motor is emax eco ii 1900kv mixed with RCINPower 2207 1860kv. It was weird that it still flies but I noticed it there was some performance loss. I noticed it every time I punch the throttle. I was expecting it won't change since it's a single 1900kv only. Any ideas? It was actually my latest video upload. I like what you said about "if you want more torque, check out throttle expo". I think that's what you said. Do we just increase it by few decimals? Amazing myth busting video!
When using motor_output limit in betaflight does it reduce the output in the PID loop also or is it more like a throttle cut? You do a fast roll on a motor that is cut to 70% does it actually stop the roll at 70%?
With output limit at 70% the motor can only ever get to 70% no matter what. With throttle limit the PID controller can still drive the motor to 100% in sharp moves.
I think it would be fair to factor that in but the way it was told to me it was the sape of the 2306 that supposedly made it more efficient not the fact that it was lighter. Also if its just weight a lighter 2207 would also be more efficient.
Absolutely right. If you don't need the extra power of the 2207s saving the weight is really worth it. We should never carry more motor than we need it's just wasted!
For the last test, did you confirm the kV ratings of the motors? They are often not accurate. Could try running both on your test stand and use the tachometer setting to find the right throttle limit, where both motors turn the same RPM at full throttle.
It's a good point that I didn't experimentally confirm the KV. However, I don't think most pilots who run 4S motors on 6S voltage experimentally confirm their KV to set their throttle limit either, so it's still a representative test 😁 Regardless of the throttle limit(which will affect the max top end) the efficiency penalty seems to be there across the whole throttle range.
@@ChrisRosser Thanks! Very interesting. I suppose if they are running the exact same prop (like physically move it from motor to motor) then the thrust produced tracks with RPM anyways. I’m curious how 65% and 75% throttle limits with the 2400kV would plot against the other two.
Thanx Chris! What I wonder is where motor volume becomes irrelevant, at what point in prop vs motor volume is the motor big enough to be limited by KV and prop.
I’ve tested the cheap Racerstar 2508 2522KV and they felt ok in the air, maybe the rpm’s felt like not being that much affected by the props. That 5" felt good in heavy wind, pretty locked in, but not having the top end power It felt like it should have. I guess that is an indicator for bigger stator volume than needed for what the KV demanded. The JB 2407 2500KV felt like it had more top end power, and a bit more… «connected to the prop». Maybe 3000mm3 is a robust target for a steep 5-5.2" prop 🙂
nice, i can confirm i have an older 4s rig 2400kv 2207 emax eco (v1) motors that i run on 6s/ and a 6s rig running on the emax eco V2 1700kv 2306 motors. so i thought it was the 2306 that give me almost e minute more flighttimes but now i see 1700kv 6s is a lot more efficient than a higher kv motor with a trottle cap. tkx i gonna swap my older 4s motors to 6s (al my battteries these days are 6s. tkx for the great work. So for 650fg AUW freestyle/cinematic flying 2306 will be enough.
I think the graph for the first myth actually proves it true. For a given thrust (a horizontal line through both curves) the 2306 motor will always have a higher throttle value than a 2207 (i.e. 2 vertical lines down from where the thrust line intersects the curves). Therefore I have to push my throttle stick much further with a 2306 motor to get the same thrust. This equates to better resolution across the entire output range (not just the low end). But freestylers (who often make this claim) don't care about fine movements at the high end of the throttle, they care more about responsiveness at the high end which a 2207 has more of across the range. So at the low end 2306 has better control but at the top end it is less responsive so it feels like a 2207 has more control.
Absolutely right. But you can achieve the same effect by running a throttle limit, or running a 4S motor on 3S. I don't think you can claim more low throttle control just by reducing the max thrust. Throttle expo gives more resolution at the low end without losing top end.
Finally a true test on these myths, and let me add a comment on most of the "talks" flying around these things... I would like to know how many are really experiencing differences piloting something which flyes like a "crazy fly"... 🤦. The power of self-suggestion on nothing "real" greatly exceeds the reality... as commonly said in Italy, people heat up talking about "fryed air" 😃
I would be curious to see at what motor output % in betaflight does the 4s motor put out the same power as the 6s one. And the corresponding efficiency %. If it was producing 10% less thrust. Would 77 or 78% motor limiting equalize the thrust, and what would the efficiency loss be at matched thrust?
Very informative video and I really appreciate that you kept it short! However your tests have a point of error, that is the actual kv of a motor is never exactly the same as the advertised (usually +-50kv). It's actually very hard to accurately set the kv of a motor. For example I bet the 2207 and 2306 had some kv difference even though both are advertised as 1700kv. The same thing for the 2400kv. It would have been more complete if you measured the actual kv values
Interesting video. I’d like to see the test repeated with warm motors. I always understood 2306 has more surface area so stays cooler which increases efficiency. But that’s also with the thought that a motor can loose up to 30% efficiency when running hot… only repeating things I’ve heard or watched so probably all myths too.
A simple and rough volume calculation will tell us that a 2306 is 23x6=138 and a 2207 is 22x7=154 cubic mm, So no, 2306 does not have more surface area........we can also deduce that from the higher 2207 motor weight, as they are the same motor mfg construction/design.
What about running 5s on a 2306 2450 motor? No throttle cap? I would assume much less efficient vs 4s but much more thrust and acceleration? I love my 2306 2450 on 5s.
@@ChrisRosser cnhl minister 1500mah packs. Voltage sag to less than 3.5 on full throttle, but it seems as though motors accelerate much faster and I don't need as much time at full throttle to get the throw I want up and over tall obstacles. Running low pitch props so I'm pretty sure I'm not getting max speed but enjoy the low end acceleration. Also I get slightly longer flights than with 4s even with the loss of efficiency due to more wh in the 5s 1500mah vs 4s 1500mah packs. Are these correct assumptions objectively or am I just being subjective?
I did a test on a 350 gram 2fiddy using flywoo 2104 3000kv motors. with different size props and pitches. flew indoors did 2 roof punches around 10 aggressive side to side swings 10 front to back swings and fast rocking on all axis then hovered at eye level until my buzzer called 3.5v (4s 850mah r-line) = Gemfan 51x25x3 got 9:30min... Hq 5x25x3 got 9:30 both at 21% throttle... Hq5x2x3 8:30min 26% throttle (and felt the most stable) Gemfan 45x25x3 8:20min 27% Throttle (felt super aggressive on Response) Hq 4x2x3 8:00min 29% throttle... Hq 3x3x3 7:00min 35%Trottle... Hq 3X25X3 6:00min 40% ... my conclusion was just like jet engines bigger prop steeper pitch = more thrust = more economy = longer flight.. but feel like the Hq 5x2x3 is what I will use the most as I am guessing the Gf51x25x3 were over propping the motor as gps speed run maxed out at 75mph (same motors were on my 4" Hq4x2x3 290gram roma L4 getting 92Mph same quad with T-motor 1404 3800kv got 75mph 250gram) flight times were around 5:00/6:00mins no problem then did a slow 35mph cruse flight easy got 7:40min.. going to do a speed run with the Hq 5x2x3 to see if it flys faster then the Gemfan's? if so then the only way would be if they are not spinning as fast (over propping!!!) ... also did a test with a larger battery(THE FPV 120c) 1500mah (Gf 51x25x3) extra 80grams added (total 380g) gave 12:30mins .... went back to the 850mah added 50gram knife under the batt strap lost 1:00min flight time... Conclusion more Throttle needed to fly means the motor draws more amps, Over propping is only good for long range???
A steeper pitch prop will be more efficient in a hover and for cruising (as long as you keep the throttle low all the time). However it will draw a lot more power and make more thrust at the same throttle setting so that often means people get shorter flight times if they fly the same way. Shallow props give much better propwash handling, which is why I prefer them for freestyle.
@@ChrisRosser I could feel the difference with a matched props others feel air is just blowing everywhere and your trying to sit on top of it. the right ones feel like there cutting the air and the quad is suspended. you wont be able to tell until the right props go on its the same difference as flying an un-tuned drone to a perfectly tuned one
@@ChrisRosser it is kind of my point the motor spins faster use more amps if the motor cant spin up (from heavy props) it wants more amps and it cant get the amps from the battery so the motor never gets full rpm the light prop may give more speed as it don't kill the battery as bad allowing full rpm range
