Prop Direction. Should you run Props IN or Props OUT?

[@MrShutterBug]

Another great video! Thanks Chris. I have been flying props-out on all my quads for years for all the reasons you mentioned. I fly everything from whoops to 5" drones and I fly both freestyle and racing, at all sizes. I agree with your points, but I think there is actually more that could be said on the topic. Here are a few things that might be interesting to expound upon if you ever feel inclined: 1) You showed the combined effect of roll and yaw, but not pitch. The ratio of each will depend on the maneuver and on the amount of camera tilt. If you ever have a coordinated turn that involves all three axes at once, the effect can be even more dramatic (a single motor can be tripple-slowed or tripple-accelerated to accomplish change on 3 axes at once). 2) In my experience, micro drones are affected by prop direction even more than larger quads. I believe one reason is that micros are often flown at higher throttle (using most or all the thrust that is available), whereas larger drones have so much thrust on full throttle that most people use full throttle more sparingly. If a micro drone is already in a high throttle maneuver then it may not have a lot more torque in reserve. Thus, the FC might ask it to speed up to accomplish double or triple duty in a coordinated turn, but it might fail to do so. 3) In my 65mm whoops are affected by prop direction the most. I believe the reason is that the props are tucked in very close to the canopy and the canopy typically rises high above the props (relative to the distance). In a fast forward turn, the canopy badly disturbs the airflow over one of the back props, especially on the inner side of the prop. Everyone I know who races whoops runs props-out. We have even had new pilots show up with props-in whoops that struggled on the turns, and we helped them switch to props out, and even the new pilots could feel the difference in stability. 4) All the assumptions here assume airflow is coming from the front. That is true more than any other direction, but certain moves might involve significant airflow from the side, or even airflow from underneath (such as pulling out of a dive). It would be interesting to discuss how those situations are affected by prop direction. 5) I have seen one case where props-in was clearly better. If you have a whoop that is heavy for its size (like a 2-3S whoop, or a whoop with an HD camera), and you fly props-out, then you might find that it experience yaw "wash outs" (undesired yaw spin and wobbles) while pulling out of dives or power loops. If the drone is light enough, it won't happen at all. In that situation, I have found that switching back to props-in significantly improved stability. Unfortunately, switching to props-in makes those fast forward turns worse, so I still choose props-out. Side note: adding a carbon stiffener also reduces yaw washouts (heavy whoops flex more than people think in high G maneuvers). Nothing contradicting what you said, just some interesting cases to consider. Cheers.

[@ChrisRosser]

Pinned so others can read these interesting points!

[@slowentropy4531]

@@ChrisRosser That was just a cherry on top of another great video. Cheers guys

[@mattimehner9193]

Great video with great explanations, as always! Keep up the great work. Props out being better is known for a long time and has been proofed countless times. Especially whoops show this a lot. Once you count in Pitch and just calculate the thrust vectors needed for a turn you find out props out has a clear benefit in net thrust created. I do not know how strong the turbulent air effect is in comparison to that, but anyhow it is also less in props out config. Interesting would be to look at hybrid designs (front 5 inch arms, back 6 inch arms, all props 5 inch) or on back arms mounted up compared to the front arms (CMW Banggod frame) and how beneficial that is… I don’t think there is a difference between pusher and puller configuration, but I am sure you will find out!

[@slowentropy4531]

@@mattimehner9193 With the pusher configuration on whoops when I flew FPV I really liked how the pushers felt. I loved the TH for that reason and I made a Mob6 pusher and loved the way it flew also, especially with the 25k motors it felt so planted for 65mm platform and had no washout. Interested to see actual testing results on it, cheers mate.

[@MrDokturp]

@@ChrisRosser I think there is one more factor that could be considered here. This is pretty known for helicopter design at least AFAIR. Haven't done the math for quads thought. For a spinning prop in flight, the amount of lift generated is dependet on linear velocity of air flowing over blade - so it's (lin. vel.) close to zero at prop root and highest at tips. Additional air sped added by horizontal flight causes a region of zero/reverse flow on downwind side of prop disc close to its center. This creates uneven lift on prop disc and additional torque with it. As prop has a lot of angular speed this will probably be "transferred" with gyroscopic effect ono another (pitch) axis. As I said, haven't done the math to verify how influential this effect could be on quad. Quad props are also built differently when compared to helis as they seem to have variable pitch (changes with dist form root). Overall this seem like a good opton to check as it could potentially explain different behavior depending on propeller size as Mr ShutterBug observed. Would love to see someone more experienced than me verifying that :)

[@mlentsch]

Well, then... why in Christ is the betaflight default "props in"???????

[@ClubbyGT]

Thanks again Chris 👍 props out 👌👍

[@ChrisRosser]

No problem 👍

[@bladeaudio]

My experience has also been that props-out provides better cooling to a DJI Air Unit in the frame as well.

[@ChrisRosser]

Thanks for sharing that's another important consideration, especially for the vista

[@noobFPV]

This probably is most convincing argument. All others are debatable, but cooling is really important.

[@TomRolfson]

Props In = No More Spin (You're done) Props Out = You'll Bounce About (but keep on flying).

[@noobFPV]

That is weakest argument. When you fly you are more likely to hit something sideways, cause you can actually see in front of drone.

[@flannyfpv]

Props out is my preferred setup. Started with props in, made the switched never looked back👍🏻

[@MatthewTaylor3]

Same for me too

[@kaptn_kapton]

Same, had to clean my lens to often when i learnt flying. Still crashing a lot, don't have to clean every time though.

[@thecakeisalie7070]

I'm going to try props out today! EDIT: I'm back after absolutely amazing flights! For my 2.5", switching to props out improved throttle response and significant prop wash reduction. I typically have trouble keeping altitude doing a tight orbit around a post/flag. With props out, the quad felt like it was able to keep altitude by responding closely to stick input.

[@CruxFPV]

FPV meets science - thanks again Chris.

[@ChrisRosser]

No problem, let me know if there is a topic you'd like me to cover next!

[@AzizaVFR]

@@ChrisRosser Chris, I suggest you take one of you AOS5 quads, collect blackbox logs with the only variable being propeller direction, and compare its noise profiles? Design a course of flight and see if there is any actual tuning differences seen and felt. I personally have been running props out since I started flying for the very reasons you stated in your video.

[@empiirefpv]

@@ChrisRosser Hey Chris i have two other topic request which might be interessting to some. How does the Frame configuration (TrueX, SquishedX, Deadcat and others) and Center of Gravity (eg. Standart hight vs Slammed) affect flight characteristics in the real world? The theory seems pretty basic but i also thought that about props in vs props out and you blew my mind with a 17 min Video. My second request would be how to design a frame with durability and noise in mind? I and many others want to dive into frame design but we are scared of designing a noisy junk frame. Loving the Videos. Keep it up!

[@justhackitfpv]

@@ChrisRosser video on windings

[@aakashjana6225]

@@empiirefpv same I would be very interested if he discusses this topic.

[@jimmynature7661]

You convinced me to switch to props out on all my kwads. I know what I'm doing tomorrow! Great info, Chris!!

[@ChrisRosser]

Go for it! Hopefully you feel an improvement!

[@zeekayfpv2484]

Excellent video Chris - The 'Aerodynamic Efficiency' you refer to is commonly known as the Asymmetric Blade Effect among General Aviation. This is one of the reasons why a propeller driven aircraft will yaw to the right upon rotation. An interesting point to note is that when the quad is flying in fast-forward flight (straight and level), the outboard phase of the propeller will be generating more lift than the inboard (assuming props in), thus moving the effective point through which the torque (relative to point zero - for this we shall define as the centre of the frame) acts on the frame, further out. This increases responsiveness and authority as proven by T = f.d as the moment arm has increased in distance from the fulcrum. Contrary to this, when operating in a props out scenario, this moves the effective point through which the torque acts in the opposite direction (as the propeller generates differing amounts of lift throughout the cycle due to the asymmetric blade effect) which, logically, reduces responsiveness and authority. A common misconception is that the rear motors are working harder due to the 'rear section of the quad being pushed down by the oncoming air'. This is not always true. This is purely dependent on the position of the centre of pressure (COP) and centre of gravity (COG). If the COP is forwards of the COG, this will push the nose down, requiring the front motors to work harder. If the COP is rear of the COG, this will push the tail down, requiring the rear motors to do more work. The COP can change depending on the relative profile (effectively the angle) of the multirotor to the oncoming airflow and will not always be constant. I'm surprised that manufacturers haven't started developing forms of natural aerodynamic stability or instability into their airframes like they do in aviation (look at dihedral on a passenger jet and then the anhedral of a fighter jet). Take this with a grain of salt, I do not have an Aerospace Engineering degree, I only have a Commercial Pilots License with a thick interest in aerodynamics and physics.

[@ChrisRosser]

Thanks for your comment! I completely agree with everything you said. In general I don't think for my quads the COP is very far away from the COG because I don't see much I term in fast forward flight. If there was a strong pitching moment from aerodynamic effects it would certainly show up there. Authority wise, whether running props in or props out one prop per side will have the outboard phase making more lift and the other prop will have the inboard phase making more lift so I don't think that confers any advantage or disadvantage to either configuration.

[@alcoholeague6705]

So many good information well done, but why i have filling like i am again in University again 😅

[@stevo43068]

This raises the question, why is the default "props-in"?

[@MrShutterBug]

I would be interested to hear your take on "pusher" whoops vs. traditional whoops. People like to say that pushers are aerodynamically superior because the frame does not block the air that exits the prop. However, with a "pusher", the frame does block the air that is flows into the prop. Isn't that just as bad? I have never observed a benefit in performance, but I have not done an apples-to-apples comparison, so it's hard to know for sure. For me, the main advantage of a pusher whoop is that it is easier to mount an HD camera near the front, where it won't see the guards. The main disadvantage is that you can only take off from a perfectly flat surface. If you try to take off from grass or dirt, you'll probably just make a mess of things. Anyway, the difference between clean air in vs clean air out could be an interesting thing to discuss in the future, if you're interested.

[@ChrisRosser]

Very interesting. I'll add it to my list of science videos and take a deep dive look.

[@Ugly_Baby_Gaming]

the air being sucked in is like a dome/half a ball the exiting air is in a straighter cone shape expanding from the prop this is why you see air-conditioning units and car radiators suck air

[@theronin48]

Very interested in this as well.

[@Ugly_Baby_Gaming]

@@theronin48 check out jet blast from an airliner and next time you go on holiday check out a line marked just behind the cockpit telling ground crew not to go behind that point or they will be sucked into the engine that is the dome size I was on about and is 90 to the side of the engine too taking it to near the wing tip air needs to come from anywhere to fill the void of what has just been chomped up by the engine

[@kampkrieger]

@@tripleheart2970 but it will be no difference if u add a higher pressure area on the bottom/outflo or a lower pressure area on the top/inflow. However the outstream is stronger and more focused so pushing harder into the wrong direction as the inflow does on the pusher. the ducts suck in air from all sides at a lower speed than the output stream

[@anvyfpv]

So, why are Props IN default in all firmware? :D

[@ChrisRosser]

I think its just historical, but maybe I'm wrong?

[@harryhalfmoon]

@@ChrisRosser Indeed, setting in Betaflight tend to 'stick' to legacy settings for compatibility / safety reasons and / or to prevent any big surprises for existing users when upgrading (=safety).

[@srossi88]

I think one important consideration regarding clipping objects: if you fly around a lot of trees, in my experience, props in is more likely to let you continue your line through things like ghost branches, where as props out will tend to deflect you away. I prefer to just plow through those light obstacles. second consideration: cross-coordinated rolls have the exact opposite effect on authority: front motors work harder props in. this is irrelevant to racing and cinematic, but smewhat relevant to freestyle, considering any roll move when shooting footage you want to cross coordinate, otherwise your shot is just spinning around your camera angle. Of course, throughout the flight, coordinated turns will likely be more present than cross coordinated rolls. third, taking freestyle in to consideration again, Im not sure that forcing the front motors to work harder in turns is advantageous when you consider that the front motors are closer to a gopro, and thus are already working harder than they should be considering they have to work a short torque lever situation with that vertical weight. It seems in that scenario you inch closer to motor saturation sooner. lastly: shouldnt we use some sort of fluid dynamics simulation to determine the difference in advancing/retreating turbulence? I ask because, in your diagram, you seem to gloss over the fact that in props out in, the more turbulent air on the outside edge at least has a clear path to the rear prop, whereas in props out that more turbulent air is directly next to the body of the quad, and I have to imagine that is going to _something_ to that turbulent air.

[@morshaFPV]

how much is slightly better? Does the efficiency fall under the non-marginal category? Great vid! Just subscribed.

[@ChrisRosser]

It depends on prop size. An excellent pilot can notice it on a 5 inch quad. It's very noticeable to most pilots on a tiny whoop because they have lower thrust to weight and less authority.

[@powersfpv]

Wouldn't the rest props always be in clean ish air during forward flight because they're angled up above the front props?

[@ChrisRosser]

Yes. Forward flight is not the critical case though. The important situation is in high angle of attack moves where the rear props are in the wash of the front props. If you are only cruising in forward flight it doesn't matter as much.

[@TheGeordietheWitchandtheWench]

Plus frame is better than an X !! People fly X because it’s the trend and it looks nicer….. 👍

[@Peter_FPV]

Hey Chris when it comes to authority I’m just curious if you also factored in variable of pitch of the quad when flying? The rear props will no longer be placed directly behind the front props which gives more allowance correct? What are your thoughts?

[@ChrisRosser]

The pitch of the quad will be very variable depending on the movements in flight. In general however the quad is moving forward so that's a place to start 😁

[@Peter_FPV]

@@ChrisRosser correct. My thought is the more the quad is pitch forward (like racers) the more “clean air allowance” the rear motors will receive this rendering more authority to PROPS IN when at high pitch angles. You no longer have to pull air in and down as much leaving a clean air pocket for the rear motors as now you are pulling and forcing air in at much greater efficiency due to the angle. Just my thoughts on how the higher the pitch angle your quad is flying at will minimize the dirty air to the rear motors.

[@overbese]

I am a prop outy. I was hoping you would answer why betaflight default is in, & so many prebuilts come as innys.

[@ChrisRosser]

I wish I knew too!

[@scooby3133]

That made me think I was doing it wrong. Like, it's default for a reason, right?

[@BuZZarDFPV]

Luckily the difference is so pronounced to feel its really not a difficult switch. I honestly think steel is the only guy who runs props in just for its yaw feel specifically. Rest of us peasants already run props out.

[@TheDiegoAranda]

I'm certainly loving all of your videos and the information you provide based on science... but I gotta say you're probably going to make an enemy of Joshua "FPV Know-It-All" Bardwell LOL. The other day I listened to one of his podcasts and he made some snide comments about your frame greasing recommendation, and now you're recommending Props-Out configuration while he has recommended Props-In for basically forever. You should make your motto "And today you're going to learn something... based on science!"

[@ChrisRosser]

I don't think so. JB has always shown that he is prepared to consider new points of view and new information. I hope he finds this video useful.

[@ChrisBe88]

thanks for this, its great ;) just want to add for authority in turns: props out is also better because if you fly straight forward the rear motors do work harder than the front ones, so the extra work in turns in props out configuration do not add to the rear ones too, which also leads to the advantage of props out

[@ChrisRosser]

Absolutely! Another advantage of props out.

[@robinfpv4858]

I can't wait until JB sees this. Will he finally change? It's great to finally see it all laid out so clearly, and finally someone that knows what they're talking about is getting some traction. I'd also not really considered the retreating blade effects. I believe the advantages it gives in cornering has been fairly well known in the whoop racing world for a while

[@ChrisRosser]

I think this is well known in whoop racing. It's not surprising because these aero effects matter more on smaller quads with lower blade tip speed and less overall authority.

[@Retset]

I'm sure I remember a video from a long time ago where JB said props out was better

[@repairengineer]

For woops there is no question you can feel the difference props out is way better. I'll probably switch my 5" to props out the next time I tinker with it at least to try it.

[@CarbonGlassMan]

Barely hitting a twig in a tree and getting sucked into the tree, causing camera wires to be cut by props made me go to props out. That's never happened to me again.

[@onemanmob6756]

Honestly, when I just started watching this video, I thought the final conclusion would be less definitive, with both configuratios having their advantages and disadvantages. I did not expect the 'props out' to be such a clear winnner... Personally, I started on the default 'props in' config, simply because this is how my first quads (Emax TH ii whoop and TH ii Freestyle) were set up by the manufacturer, but as soon as I learnt how to reverse the props I switched to 'props out'(I first reversed the motor direction by swapping wires, because I didn't know yet of BL Heli software 😶) and never went back to the 'props in' on any of my quads again - whether I build or buy kwads I always make sure they run in props out set up. It's reassuring to learn that there are other important reasons for running the props out, beyond just not wanting the kwad to look like a dirty lawnmower 🙄

[@ChrisRosser]

When I started looking into this I though it would be more balanced too!

[@cloudcamdrones]

I always fly with IN props, but my new drone came with OUT props, I can´t explain what i am felling but it´s strange for me fly with OUT props. Today I´ll change the direction of the props to see if(for me and the way I use the drone) change something or it´s because is a new drone(I discovery the props are OUT after fly a few times, so I think it´s not a placebo hahaha). I will return here to tell if changed something in flight or not. My drone is an iFlight Green Hornet.

[@jandomingo9806]

Ive tried props out it does feel something is helping me in turns... but i dont like that feel.

[@ChrisRosser]

Feel can be dealt with in rates and RC filtering. If the quad is handling better you should still be able to get the feel you want by changing your rates settings.

[@daveopie1234]

For the reasons you give, I generally run "props out". However, I am currently building a cinewhoop. With the ducts/prop guards cutting down on the crosswind, many of the advantages of "props out" don't matter any more. So I think I'll go with the Betaflight default of props in for my cinewhoop.

[@ChrisRosser]

I would love to know if you notice any difference between in and out on your cinewhoop!

[@charlsfpv8464]

An Idol Chris, really blow my mind every single video of your!!! FPV BIBLE!!! THANK YOU 🙏🏻😊👏🏻👏🏻👏🏻👏🏻

[@ChrisRosser]

My pleasure!! More to come 😁

[@erlandfpv]

Im always using props out, 2inch...2,5inch...3inch,, 4inch,,5,,even my 7inch quad .. i feels more comfort when im using props out...

[@majki5900]

great content, thx for that🤘But it made me wonder. Why most DJI drones have props IN if it has little advantage? I can't get it? They must be aware of this, right?

[@moek]

Try to make a fast turn with a TINY-WHOOP and watch how the back side will dip, not sure why but this effect is exaggerated on tiny whoops… props out FTW

[@ChrisRosser]

Tiny whoops have so much less thrust and authority I think aero effects matter even more.

[@desertclimbers]

I turtle mode so much, with props OUT, turtle mode covers my lens with junk (or pits the lens with rocks) during reverse direction. Therefore I only fly props IN. This way, turtle mode doesn't make it impossible to see (or ruin my camera lens) when I get back upright and flying. I conformal coat everything, and use plugs in my USB ports to keep wet junk from killing my electronics, since turtle mode throws stuff into the flight controller. 🤣 Nothing else matters to me since I claw my way out of pretty much everything using turtle mode. LOL When I crash much much less both racing and freestyle- then I'll go back to props out. Great video, though. Mad props to ya!

[@John-zj3kg]

Hi Chris, I have a floating-at-zero-throttle problem on my two cinewhoops (a slammed squirt and a terraplane) that I've spent quite some time debugging with advice from people in the community. I got a video about it here kzbin.info/www/bejne/qXzJcmBmf8-Lh6s. This is a few experiments old but it sums up the issue I've been seeing... I have more videos/data to share if you got the time. I had some discussions with Brian White, who highlighted one of the BBX signatures is that there's a fixed PID-I on YAW when the quad is 'floating'. Some theories were that the quad lacked yaw authority or there's some drag on one end of the quad which causes there to be a constant yaw request from the PID controller. After trying to fiddle with Yaw I/P gains, I discovered the only solution was to flip from props-out to props-in. Worked on both quads without any changes other than the props and ESC direction. And I re-wired the ESCs to flip the direction on the front 2 motors to rule out the ESC. Not sure what to make of that. Have you heard anything like this or have thoughts on this?

[@volodymyr3169]

Would be nice to see some proof to your theory about air turbulence effects on the blades in a form of a cfd analysis or real world measurements. While you can argue qualitatively about advantages/disadvantages in the case of object collision, you cant get away with qualitative arguments when it comes to air flow, you need some numbers.

[@pinewaves_]

The one time I switched to props in, I shattered my fpv camera. I'm switching back to props out!

[@xflixfpv]

Nice So i been doing it right all the time :) Thanks for this great preparation and presentation as always :)

[@maggoffm7586]

Nice videos. Bit one question. For ducted whoops its the complete opposite. With props in you dont get a yaw blowout during a dive. Qith props out you will get a yaw blowout. Can you explain why this behaves so different compared to non ducted rigs?

[@SeismicCWave]

This is 2 years old and I am not sure if anyone will read this. However I have three AOS T3 quads in different configuration. I asked Chris about tuning because I was having issue with at least one of them. It bobbles a lot. Chris suggested lighter props which I bought. It helps but not the one that bobbles. Then I noticed I was running props in on that particular quad. After changing rotation direction of the motors I am now flying props out on the quad and it is behaving much better.

[@ermannobona2755]

Complimenti Crhis...domani provo a invertire, e mi iscrivo subito al tuo canale,finalmente qualcuno che parla di questo argomento interessante.Grazie👍

[@ChrisRosser]

Thank you for your comment. I hope you like props out!

[@ermannobona2755]

@@ChrisRosser l'ho provato ora...sul mio 6 pollici lo trovo più fluido e silenzioso primo test di 5 minuti e già mi piace....ora vado al lavoro, ti aggiorno👍

[@TheRealStevenGlen]

ty

[@triggermovies]

But in a coordinated turn, we are also pitching back, and the front motors are spinning up for that. Right ? In a props-out configuration, it means that one of the the front motors has to spin up for all 3 rotations (pitch on top of roll and yaw), while in a props-in, it's more evenly distributed. Does this have an impact or is clean air more important ? Edit : I had pause the video to write this comment right before you talked about blade stalling. So in fact, props-in might compound this further, as in your example, the rear-right motor has to spin down "3 times" Versus in props-out, the front-left motor having to spin up "3 times". Which might not be an issue unless we max it out ?

[@kwadkenstine4988]

Hi , please can you do a similar video on X8 quads. I build and fly x8 quads using only 4 motor outputs and running the upper and lower motors on the same arm in the same direction. in effect an 8 motor quadcopter not an octocopter. I know for a fact that i can drop 4 motors or props and it still flies , just at half power. But if you try the same in x8 config it does not work so well . I have tried to inform folks of this , but all other x8 type craft i have seen run octo config with 8 separate motor outputs, If redundancy is important those running 8 motor outputs are doing themselves no favors , but no one listens to me, . Your work is FANTASTIC , keep it up.

[@m2kfpv449]

Thanks Chris. This is exactly what I have been testing and was hoping you would get to it. MrShutterbug (Nate Payne) opened my eyes to props out with his Beta75x washout tuning a couple years ago which dramatically reduced the insane yaw jerks on that model. I now run props out on the majority of my fleet. 🙏

[@ChrisRosser]

I think this matters most on smaller quads where authority and efficiency are less overall so any improvement matters more.

[@colebtl]

the only downside about props out is that USB connector will be jammed or even damaged by debris one of my FC got handicapped because of that but it's a simple fix with some cover thingy other then that it's all pros and no cons for me.

[@deckyrizkiadi]

Very nice video analysis. Would this works on whoop (ducted) quad?

[@rasta1979]

Best explanation ever found I'm a new subscriber, keep up the good work.

[@ZentaRobotics]

Subscribed! I'll give it a go on my quads.

[@h2o-fpv623]

O well at least I got half of my fleet with props out and my last build will change it to prop out. And check it out . Thank u for this video.

[@Gosuminer]

This is a perfect summery of my own thoughts on the topic back when the in/out discussion started around 3 years ago and I flew all my quads props out ever since (not that it would make any difference on the skill level I am at).

[@ShebanFPV]

I've switched over all my quads to props out and feel no difference 🤷🏻‍♂️.

[@freddie514]

After watching this, I had nothing much else to do so I figured I'd swap on my EMax Hawk Pro to props out (did put a new set on for complete fairness), and ran a few packs thru it, decided props out actually feels better. Amazing video, absolutely love the deep dive analysis on the individual subjects!

[@ChrisRosser]

Glad I could help!

[@MSR.]

Amazing job explaining this subject matter. Thanks 🙏

[@ChrisRosser]

You're welcome. I hope it helps!

[@MUNKYFPV]

I have a question regarding props you might have an answer for. Why does everyone I know seem to damage mostly props of one direction, either right hand or left hand so we end up with a stack of spares that are only left or right handed??

[@ChrisRosser]

Everyone has a preferred turning direction. I think its just that you commonly fly closer to objects on one side or the other based on your preference so always crash on one side.

[@MUNKYFPV]

@@ChrisRosser Hey that makes sense, didn't even think about the tendency to fly closer to things on one side.

[@erlandfpv]

I decide to use all my quad is props out , because i never using props in before. I just like it. And feels better, than my friends quad which they always using props in.

[@VisualGadget]

Props out only to keep HD camera clean and avoid collisions.

[@BonemysterFPV]

I would run props out on all my quads until 2019 I was building a 40mm propped tinywhoop carrying a naked gopro. For months it was unflyable until one day i went from props out to prop in as a last resort to try it out. It flew amazing. To this day I make all my whoops run props in but all my bigger quads run props out.

[@wavesummit]

Great video, I've always run props in because it's the betaflight default and I am lazy, but now I am definitely thinking of switching.

[@ChrisRosser]

It's worth trying props in and props out and seeing if you prefer one or the other 😁

[@aphinion]

And here I thought it doesn't really matter and the only real difference is that you either spatter your lens or your electronics, lol. Pretty trong arguments for outies though! I may give it a try! :3

[@Alluvian567]

Love your videos. Orange and green to indicate different things is not a great choice of colors for colorblind people. Depending on the type of color blindness of course. I have all three types to varying degrees and could not tell the orange and green arrows apart at all.

[@JasonMatthewCrabtree]

The only caveat to the camera issues is if you use Turtle mode in areas that have gravel and loose aggregate. If you run props out, they'll be throwing rocks and gravel at the lens of your camera. I have a runcam hybrid betnow has a textured lens do to sand getting thrown at it while in Turtle mode. The issue is soft pretty easily though, it's as simple as not using Turtle mode when gravel is present

[@lanxang173]

We have screen protectors for phones. I often wonder why manufactures don't include a small insert and method to attach it just in front of the lens. I now leave the crappy plastic lens protector that comes with the camera on because of how delicate those lenses are.

[@staticfpv881]

Props out for me , props in pulls u into anything you hit . Pros out saved me many many times . Down side , in turtle mode yr lens will get dirty

[@k1ortia]

What people fail to realise is that this hobby is about fun..and not complicated science.. come on?

[@ChrisRosser]

For me complicated science is fun! I am a hopeless nerd 😁

[@k1ortia]

@@ChrisRosser Hats off to you, you,ll be my go to guy when I have a scientific problem I require answering..😉

[@ChrisRosser]

@@k1ortia You bet. Looking forward to it 👍

[@starsstripesjacket]

I started running props out when people started saying it was better for whoops and I just wanted to keep it the same with all my quads. Thank you for these videos, they're great :)

[@ChrisRosser]

Glad you liked it!

[@XENON13]

Is this why I always heavily prefer to turn to the left?? 😲

[@ChrisRosser]

Haha, the same is true for right turns just mirrored 😋

[@XENON13]

Ah I see now after rewatch. Shouldn't have watched this while I was half asleep lol

[@TrentTationnaiseXization]

TLDR; Props out.

[@ChrisRosser]

Go science!

[@ampedfpv]

Thank you Chris. You just answered every question I've had about this topic!

[@ChrisRosser]

My pleasure!

[@rubinhodrone9204]

Passando pra prestigiar aquele like e 🤜🤛👍👍😉

[@BayLA415626]

sweet I knew I liked them out for more than just my cam getting junk in it

[@dandan1364]

Wow very interesting. I always thought it was mostly a symmetric system when to end but when you couple a turn and realize you’re also going forward then it’s not at all symmetric. Very cool!! Thank you.

[@ChrisRosser]

That's it, the forward flight makes everything asymmetric and gives props out an advantage!

[@ojkolsrud1]

Would be interesting to see a blackbox log. Fly the "exact" same path with the same quad in the two different configurations and everything else equal, and discuss the difference=) I'll switch to props out to check this out! I've always ran props out on my 3", but the 5" is props in.

[@KrotowX]

It would require computer controlled flight. Because no way hoy you manually would repeat exactly the same path. Though I got the idea.

[@ojkolsrud1]

@@KrotowX But you can go "powerloop under this tree, fly straight past the field, do a punch by the house, hover at the rock", and so on.

[@KrotowX]

@@ojkolsrud1 Indeed I can. It will not be exactly repeated previous flight route, but yes ;)

[@GoatZilla]

Alright, now do regular prop-on-top vs. lawnmower!

[@192kalle1]

why is props in the default on betalight ?

[@docmatt31765]

I use to only run props in and switched this year and it is way better

[@daich]

@snakefpv used to do blind tests all the time...i miss those. This needs a blind test.

[@ChrisRosser]

100%. I wonder if you can feel the difference for a 5in. You definitely can for whoops!

[@SpiritOfAirbender]

When i switched to props out after the first few months of flying, I never went back until recently with iNav. It started mostly with wash out on whoops when coming out of a dive, etc.

[@Dragonewiz]

and reposition the props in the right order??? so it will fly in this prop out ???

[@Lucas-eq1ul]

Tomorrow i will change my motors orientation

[@lanxang173]

Awesome video, thank you for doing this! It answered everything I was pondering, and clarified my main sticking point which was reversing props should just "flip" torques. I hadn't thought of the clean vs. dirty air issue with the front props and advancing/retreating blades. Also made me happy that I didn't waste my time swiching quads to props out this week. 😅

[@spikester]

Less frame resonance too it seems with props out, at least on my deadcats, must be better for the filtering?

[@b1icky]

I crashed my 5” quad and had to replace my esc. After doing that and making few other adjustments, (Lighter battery straps, less tpu mounting, no motor wire sleeving) The quad was actually 40 grams lighter. But It flies noticeably worse, the motors run hotter, and low ground passes were harder to pull off. I adjusted the pids and noticed I can’t push them as far. The only real variable that would make performance that much worse would be my prop direction. I got lazy and hate using bl32, so my motors are running inwards now. Never knew it made that big of a difference, I just ran props out because I used to crash my whoops often.

[@ChrisRosser]

Crashes can cause delaminations in the frame which will affect vibration performance. Even if the frame looks OK it can become more flexible. That might be the cause. If you're still having trouble after switching back to props out check that all the arms feel equally stiff.

[@Moustafa-Eldessouki]

how does it works for Cinewhoops ?

[@muggzzzzz]

Motors with CCW props are usually have CW thread on the axis, and vice versa. Should I resolder my motors to switch from props in to props out? Or could I just change settings in betaflight?

[@ChrisRosser]

Nowadays most motors have the same thread for both directions and use a nyloc nut so it doesn't come loose. No need to swap motors just change it in BF.

[@jkpoynter]

Very persuasive explanation without showing any advantages to props in, do you work for CNN by chance? 😂

[@ChrisRosser]

Which advantages did I miss?

[@InteractiveDNA]

All my drones are in Props outs, I always told people that out is pure commonsense in many ways. Like swimming 🏊‍♂️ Front Crawl in witch is most effective just like Props Out! Physics always win over ignorance. Great Job!

[@rumenradkov6797]

I totally agree with all this in your video. Great job with it and and some benefits of flying with props OUT. There is something to be taken in consideration with props OUT is in scenarios when they impact with a HARD object (hard to be moved by kinetik energy of the quad) the quad is being "thrown away with a dangerous speed of non predictable direction". So best is when you dont have damage to your quad or anything else but mostly a strap is cut, battery is away from quad etc. and not last no body hopefully is not hurt. I was flying with props out for an year being witness with these unxpected and upredicted "quad thowbacks" since then I fly with props IN. Did you experience same behaviour of an impact? Thank you!

[@ChrisRosser]

That's a great point, props out does throw you clear of objects, sometimes quite forcefully! I have had that experience too.

[@alexegorov8774]

Amazing explanation👍🏻

[@luckyfpv323]

I like props in. I'm wondering why didn't you draw the second set of red ellipses on the props out dirty air example? It looks like props in leaves cleaner air under the body of the quad, in the same direction the quad is likely moving. Any thoughts on this?

[@ChrisRosser]

In the props out configuration there isn't such turbulent air on the outboard side so no red ellipses. This shows an advantage of props out. 👍

[@gji25]

Thanks for the info

[@elis51501]

I have both and after watching this video all the facts make sense, and the glancing reaction to scraggly and what not makes it all worth while to go with pros out rotation

[@Bean-Time]

For the coordinated turn point, wouldn't you also have to account for the fact that the quad will pitch forward given no pitch input, needing the pilot to pitch back to keep the same angle. This would cause the the front motors to work harder regardless of prop direction and could reduce the possibility of a stall in the front left motor (on a props out quad) but also could max out the front right motor. JB covered the whole 'pitching forward in a coordinated turn' thing on a video called "why pilots don't pitch forward as much as you think" or something. (Sorry I can't link I'm on mobile)

[@Bean-Time]

kzbin.info/www/bejne/apTInZh_ptNoja8

[@MrSmithFPV]

Ok, you got me. I will change my quads from Prop-In to Prop-Out! :-)

[@ChrisRosser]

Welcome to team props out!

[@MrSmithFPV]

@@ChrisRosser Thanks!

[@a_mouse6858]

Cool analysis. But if a quad is flying quickly through the air with 45 deg forward pitch, I would think the rear props get pretty clean air. Has anyone modeled this in CFD to see if it is a real issue?

[@ChrisRosser]

Level forward flight is not typically a problem for either prop configuration. It's more important for agressive high alpha acrobatic moves where the rear props can end up in dirty air from the front props. Particularly prop wash situations.

[@whitmeade4834]

Great video, actually made me change my prop direction to props out

[@phillipneyman9338]

how are you only at 3k subs? there is something fundamentally wrong with that....

[@ChrisRosser]

I'm very happy to see the channel growing quite fast. Tell your FPV friends!

[@MadDragon75]

Props out 😏👍 all of my quads are props out.

[@maelradec6766]

Props in because chief said so

[@kantony6694]

I am at one with the props!!! Lol

[@sleepingbearffg5008]

Out by far

[@ChrisRosser]

Yeah, another Props out pilot! Thanks!