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
3 жыл бұрын
Pinned so others can read these interesting points!
@slowentropy4531
3 жыл бұрын
@@ChrisRosser That was just a cherry on top of another great video. Cheers guys
@mattimehner9193
3 жыл бұрын
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
3 жыл бұрын
@@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
3 жыл бұрын
@@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 :)
@flannyfpv
3 жыл бұрын
Props out is my preferred setup. Started with props in, made the switched never looked back👍🏻
@MatthewTaylor3
2 жыл бұрын
Same for me too
@kaptn_kapton
2 жыл бұрын
Same, had to clean my lens to often when i learnt flying. Still crashing a lot, don't have to clean every time though.
@CruxFPV
3 жыл бұрын
FPV meets science - thanks again Chris.
@ChrisRosser
3 жыл бұрын
No problem, let me know if there is a topic you'd like me to cover next!
@AzizaVFR
3 жыл бұрын
@@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
3 жыл бұрын
@@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
3 жыл бұрын
@@ChrisRosser video on windings
@aakashjana6225
3 жыл бұрын
@@empiirefpv same I would be very interested if he discusses this topic.
@zeekayfpv2484
3 жыл бұрын
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
3 жыл бұрын
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.
@starsstripesjacket
3 жыл бұрын
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
3 жыл бұрын
Glad you liked it!
@m2kfpv449
3 жыл бұрын
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
3 жыл бұрын
I think this matters most on smaller quads where authority and efficiency are less overall so any improvement matters more.
@daveopie1234
3 жыл бұрын
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
3 жыл бұрын
I would love to know if you notice any difference between in and out on your cinewhoop!
@charlsfpv8464
3 жыл бұрын
An Idol Chris, really blow my mind every single video of your!!! FPV BIBLE!!! THANK YOU 🙏🏻😊👏🏻👏🏻👏🏻👏🏻
@ChrisRosser
3 жыл бұрын
My pleasure!! More to come 😁
@desertclimbers
3 жыл бұрын
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!
@skree_fpv436
3 жыл бұрын
I used to run props in back in the day. I switched initially because of camera fouling but quickly noticed the slightly better flight characteristics and bouncing of of branches instead of being sucked into them. Been running props out ever since. Thanks for showing the science behind it!
@ChrisRosser
3 жыл бұрын
No problem! Its nice to see the video is interesting even for those already running props out 😁
@rasta1979
3 жыл бұрын
Best explanation ever found I'm a new subscriber, keep up the good work.
@tonhabraken9339
3 жыл бұрын
Great explanation and detail! Thanks. Been flying props out for ages because it just ‘felt’ good. Now I know why.
@tonhabraken9339
3 жыл бұрын
By the way… something I’ve been wondering about. Why are we still manually ‘tuning’ our quads? Shouldn’t it be possible for ‘the software’ ( using ML? ) to do a BB analysis and adjust filters and pids accordingly? After that.. all we should just tune ‘stick feel’ .. Or has that already been done and discarded?
@ChrisRosser
3 жыл бұрын
It's very hard to predict the effect of changing PIDs in isolation. I'm speaking with a dev from AI drone simulator it might be possible to extract flight parameters from blackbox, auto tune in the sim, then get out the right PIDs for your quad. We'll have to see!
@tonhabraken9339
3 жыл бұрын
@@ChrisRosser Now that’s an interesting experiment. Guess I’ll have to get that sim now… unless it’s Windows only. Hah. Thanks!
@WindjumbieFPV
3 жыл бұрын
I always run standard rotation but this video just made me decide to try “props out” as there is a clear scientific explanation about the benefits of it. 👍🏽
@ashd1930
Жыл бұрын
An amazing explanation to what can be a daunting subject to get your head around. Nice work.
@erlandfpv
2 жыл бұрын
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.
@andywakelin1380
3 жыл бұрын
I've only ever run props out on indoor toothpicks to help bounce off when clipping objects. Most definitely going to explore props out on the other quads after watching this! I really like your copter physics videos. Thanks for sharing.
@RobertLeeuwerink
3 жыл бұрын
Thanks, had not thought about switch prop in vs out direction, just used the default betaflight. After your video I gave it a try and men I just got an extra 3 to 4 minutes flight out of my quad, from nearly 9 to 10 min to over 13 minutes. Not to mention banking turns are much smoother plus better turn control in general. Same quad, battery, blades and that in heavy winds... flying a light weight 5" which is setup for long-range. just around the 250grams
@ChrisRosser
3 жыл бұрын
Great to hear! I'm glad the video was useful to you. 😁
@RobertLeeuwerink
3 жыл бұрын
@@ChrisRosser watch your video on prop size and motor choice, I'm running 1404 4850kv on 5" bi blade low pitch. To me this is my best quad yet, this is my 4th quad and second that I put together myself. To be fair this is the first I got good PID setup after watching tons of videos on it of AUV. But there is something quite different from a 4" to a 5" quad that I would like to know more about. The responsiveness with same setup just going up that inch makes it feel much more stuck/grippy
@tripleheart2970
3 жыл бұрын
Thanks for another great and informative video Chris. I tested props in vs props out on low authority whoops to see if I could eliminate washout problems. With props in I would get uncommanded rolls during a washout, and with props out I would get uncommanded yaws. Washout would cease to be a problem if the quad had enough authority. Washout was also reduced by making sure I gave the quad extra throttle during a hard turn. On a quad with good authority, I had a hard time telling any difference between props in or props out, but I need to do a lot more testing on that as my flying skills have improved greatly since my initial experiments. Thanks again, I am grateful for all I have learned from you.
@ChrisRosser
3 жыл бұрын
These aero effects matter more on whoops than bigger quads. The difference in feel is quite slight on a 5inch I think.
@MUNKYFPV
3 жыл бұрын
Great video mate 👍😎 I’ve been running props out for a long time for the reasons you mentioned but didn’t know about the potential aerodynamic benefits. Theres another benefit to props out if you run rx antenna backwards off the rear arms etc. they are less likely to be damaged by a prop strike, turtle mode aside. There’s two caveats I would say. Don’t land or take off on long grass, or disarm quickly when landing, or your stack will get covered in it. And best to have all your quads in OR out, a mixture can easily end in putting props on backwards which can suck big time 😂
@ChrisRosser
3 жыл бұрын
Definitely. I only run props out to avoid that problem. The trick is to land like a freestyle pilot. Disarm when you are still 2m off the ground flying 10mph😜
@ClubbyGT
3 жыл бұрын
Thanks again Chris 👍 props out 👌👍
@ChrisRosser
3 жыл бұрын
No problem 👍
@godsun358
3 жыл бұрын
You are the MAN Chris and what you just explained makes good since brother so I'm switching to props out. Thanks good buddy.
@gammagonad1657
3 жыл бұрын
I absolutely can with out a doubt can tell a HUGE difference when I clip a tree or even a post. I probably bounce off at least 50% of the time, depending on how hard I clip something. Sometimes it’s amazing how well it works. That is the main reason I ONLY fly props out. I don’t know why it isn’t the standard configuration. I have definitely noticed other advantages, but now see more through the turbulence diagrams. I always FELT that it flew smoother, and just makes more sense to me.
@SpiritOfAirbender
3 жыл бұрын
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.
@MikeBogartRealtor
3 жыл бұрын
Subbed! This is the first of your vids I’ve seen. This is great stuff!
@ChrisRosser
3 жыл бұрын
Welcome aboard!
@aakashjana6225
3 жыл бұрын
The back motors work harder anyway because we fly pitched forward which means there is a bit more drag pushing the rear down and the motors work harder to maintain that angle. So by running props out we basically relieve the rear motors. Credits: JB
@bladeaudio
3 жыл бұрын
My experience has also been that props-out provides better cooling to a DJI Air Unit in the frame as well.
@ChrisRosser
3 жыл бұрын
Thanks for sharing that's another important consideration, especially for the vista
@noobFPV
3 жыл бұрын
This probably is most convincing argument. All others are debatable, but cooling is really important.
3 жыл бұрын
These videos are so good and informative but so hard to get through, not that it's boring just to long and there's only so much time in a day.
@ChrisRosser
3 жыл бұрын
Some people watch at 1.5x or even 2x speed. Might be helpful 😁
@alexegorov8774
2 жыл бұрын
Amazing explanation👍🏻
@ermannobona2755
3 жыл бұрын
Complimenti Crhis...domani provo a invertire, e mi iscrivo subito al tuo canale,finalmente qualcuno che parla di questo argomento interessante.Grazie👍
@ChrisRosser
3 жыл бұрын
Thank you for your comment. I hope you like props out!
@ermannobona2755
3 жыл бұрын
@@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👍
@JasonMatthewCrabtree
3 жыл бұрын
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
3 жыл бұрын
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.
@docmatt31765
3 жыл бұрын
I use to only run props in and switched this year and it is way better
@KrotowX
2 жыл бұрын
I'm using props out for 5 years already, when it became a thing. Definitely easier to escape from contact with tree branches at one side which may happen a lot when you do freestyle between trees. Inward props in such circumstances usually tie branches around quad in a second with known outcome. Also cleaner camera lens. With props in often had dirt and grass thrown on camera lens on liftoff which annoyed me a lot. Didn't noticed authority problems for outward props as well.
@ChrisRosser
2 жыл бұрын
Exactly the same experience I had. Props out for me now 100%.
@jejefpv
3 жыл бұрын
I run props in because I prefer to take 5 seconds once in a while to clean my camera than risking to short something on my FC or ESCs because of wet grass projections (and spending much more time cleaning electronics). But statements about authority and aerodynamic are very interesting and make me hesitate to switch... ;) Thanks for the video !
@edfroxt7294
3 жыл бұрын
I cover all of my electronics with silicone isolation liquid, this helps with wet grass projections)
@ChrisRosser
3 жыл бұрын
I don't blame you. Never had it happen to me but I do get worried when my stack looks like a grass box from a lawnmower!
@jejefpv
3 жыл бұрын
@@edfroxt7294 I was used to do so, but it makes maintenance quite messy and silicone coating is a bit fragile when cleaning with a toothbrush, always pros and cons ^^
@BonemysterFPV
2 жыл бұрын
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.
@b1icky
3 жыл бұрын
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
3 жыл бұрын
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.
@CarbonGlassMan
3 жыл бұрын
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.
@butcher
3 жыл бұрын
Wow, super impressive explanation again. Thanks!
@ChrisRosser
3 жыл бұрын
Glad it helped!
@butcher
3 жыл бұрын
@@ChrisRosser We always arguing with the local guys in Hungary ( central europe ) now I simply share your video and no one will arguing on this again, so yeah, thx again :D :D
@neilfpv
3 жыл бұрын
Cool! I will try props out. I've never tried it. I should be able to notice difference since I've been flying props in for close to 2 years now.
@kwadkenstine4988
3 жыл бұрын
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.
@xevox3d627
3 жыл бұрын
I really enjoyed your scientific explanation :) I have been running props in all the time, cause its the default on betaflight, but after your video I am defenetly trying out props out now
@alcoholeague6705
Жыл бұрын
So many good information well done, but why i have filling like i am again in University again 😅
@TheDiegoAranda
3 жыл бұрын
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
3 жыл бұрын
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.
@BuZZarDFPV
3 жыл бұрын
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.
@YotaGuy_Kyle
3 жыл бұрын
I never thought of trying props out. Until I bought a Iflight xl5 BNF. That came props out. I did notice slight differences compared my built iflight Xl5
@aerialimagery3216
3 жыл бұрын
Amazing content! Going to switch to props out and see if I notice. It would be cool to try to do two similar flights back to back props in versus props out and compare box logs.
@nathanielakkermans
3 жыл бұрын
Good video again, I run all my quads pros in. Just because it is default. One time I experimented with reverse direction but when I got a broken prop and replaced it on autopilot with a new prop with the prop in direction the quad was almost eating my face at arming😝 so after that incident I never did it again. But your theories sounds interesting so I will give it a new try. Thx
@alextravine9422
Жыл бұрын
I noticed long ago that props out had a huge difference in the agility of a quad using stretched x frames as opposed to agility of compressed x frames using props out. I think props in was actually preferred on those butterfly (dead cat) frames because the ofset positions of front to back props.
@scooby3133
3 жыл бұрын
Not knowing which is best, props out seemed the most logical to me when I first started. I print shields that attach to stand offs to protect the electronics from getting dirty.
@justinslaight
3 жыл бұрын
I subbed to ya, very informal and you do an amazing job, thats the least I could do. Thank you!
@ChrisRosser
3 жыл бұрын
Much appreciated!
@russwishtart
3 жыл бұрын
Chris' channel is a National Treasure
@ChrisRosser
3 жыл бұрын
Now I'm paranoid Nick Cage is going to show up! Thank you for your kind support.
@russwishtart
3 жыл бұрын
@@ChrisRosser Quick question for you my man: have you ever found Dmin to be beneficial? In any quad, for any application? Seems to be a total dog of an option any time I have tried it regardless of size, motors, etc.
@ChrisRosser
3 жыл бұрын
@@russwishtartI use Dmin as a Dboost. So I have my Dmin set to the maximum possible D gain an then I crank the Dmax up higher to allow me to push P gains up more. On my AOS 5 build I have Dmin set to ~50 and D gains of ~70. P gains are ~90. I'm working on a tuning video to take everyone through my process, I hope you enjoy it.
@russwishtart
3 жыл бұрын
@@ChrisRosser Wow! I never heard of anyone tuning Dmin this way. Interesting!
@slinkyfpv
3 жыл бұрын
I wish we had some numbers to go with this. I agree with what your saying but without numbers I fear switching over may be a moot point. Opinions based off of personal experiences are rarely reliable. I've got racing builds that run props out and freestyle builds that run props in. No preference so far.
@dieguerson
3 жыл бұрын
so interesting! even for a newbee! Thank you!
@jonchappell9544
3 жыл бұрын
Great video thanks for the information!
@ChrisRosser
3 жыл бұрын
Glad it was helpful!
@mazyarahmadi5424
3 жыл бұрын
Very interesting and makes sense. For me, I’d hate to get all the crud on the electronics though, but I think that’s the minority of time. I recently just damaged my quad camera, I wonder maybe it would have been spared if it was props out. I’ll try the out, ty for the analysis
@rumenradkov6797
3 жыл бұрын
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
3 жыл бұрын
That's a great point, props out does throw you clear of objects, sometimes quite forcefully! I have had that experience too.
@MPQuads237
3 жыл бұрын
I am running props out for a long time mostly because I don't want dirt on camera, I don't use turtle mode because of long grass and I also liked the idea that props are pushing out objects. I do not recall any significant impact on flight performance when I made the switch.
@erlandfpv
3 жыл бұрын
Im always using props out, 2inch...2,5inch...3inch,, 4inch,,5,,even my 7inch quad .. i feels more comfort when im using props out...
@Adam-kb2mn
3 жыл бұрын
Hi.How about a soft mount of motors test?Was all the rage a couple of years ago but don't see it anymore.
@maggoffm7586
Жыл бұрын
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?
@crazicat
3 жыл бұрын
Keeping my quads out of trees is why I go props out on my 3-5" quads. But after trial and error on my 75mm whoops where that's a moot point, I have found props in flies better for me.
@ufopilotFPV
3 жыл бұрын
Regarding clipping objects.. when I race I often clip gates with my rear props as I pre-turn through them (see my last vid for a perfect example of this, first lap I clip the gate before the ladder), coupled with not wanting grass on my stacks i run all my racers props in !
@bkfpv
3 жыл бұрын
Thank you. Very informative.
@deckyrizkiadi
3 жыл бұрын
Very nice video analysis. Would this works on whoop (ducted) quad?
@powersfpv
2 жыл бұрын
Wouldn't the rest props always be in clean ish air during forward flight because they're angled up above the front props?
@ChrisRosser
2 жыл бұрын
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.
@triggermovies
3 жыл бұрын
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 ?
@MadDragon75
3 жыл бұрын
Props out 😏👍 all of my quads are props out.
@Tonynux
3 жыл бұрын
Great explanation!
@waldemarkraus2855
3 жыл бұрын
Props out is also less noisy on my 7" when running biblades and I see less resonance in my BB logs. It's very strange, but tried switching several times between props in/out and could reproduce this effect every time.
@FPVish
3 жыл бұрын
Wow. alot of information, but makes so much sense. Thank you. Wish KZitem made an additional button just to subscribe again. Id hit it. 🔥🔥🔥
@pawellochowski
3 жыл бұрын
Great video!
@ChrisRosser
3 жыл бұрын
Thanks!
@TweakRacer
3 жыл бұрын
Exactly why I've always run props out. BTW, pusher props are only more efficient than tractor props in theory, as no real world application in full scale or model aviation feeds a pusher setup with clean enough air.
@willfpv4475
3 жыл бұрын
Thanks for the awesome video
@Dragonewiz
3 жыл бұрын
and reposition the props in the right order??? so it will fly in this prop out ???
@sdover0123
3 жыл бұрын
Awesome video, very clear and understandable. I'm going to change to props-out on my cinewhoop to see what change it makes tonight! However, I did feel that my tinywhoop (tinyhawk 2) felt better, somehow more precise with props in? Would this perhaps have anything to do with the fact that the angle of flight is not as significant?
@192kalle1
3 жыл бұрын
why is props in the default on betalight ?
@moek
3 жыл бұрын
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
3 жыл бұрын
Tiny whoops have so much less thrust and authority I think aero effects matter even more.
@colebtl
3 жыл бұрын
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.
@a_mouse6858
3 жыл бұрын
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
3 жыл бұрын
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.
@CalleyyyC
3 жыл бұрын
Running props in, if an object is grazed, would it be less susceptible for the object to also come in contact with the rear prop? Given that the impact provides just enough torque from the front prop impact to fish tail the rear of the quad around the object? And the opposite for props out - more susceptible for both front and rear props on a given side to come in contact with an object that is grazed?
@ChrisRosser
3 жыл бұрын
An interesting thought I have rarely seen front and rear props damaged from clipping something running props out so I don't think its a problem.
@CalleyyyC
3 жыл бұрын
@@ChrisRosser thanks, I’ve only flown micros and with props in but now considering props out. Sounds like this is a non issue, and would be even more so on larger (more powerful/heavy) quads that are less impacted by the same objects
@andrewut7ya511
3 жыл бұрын
Very interesting, ive been curious about this but not curious enough to look into it. I needed this. Currently running props in as thats just hiw my nazgul came, can any drone be switched in betaflight? Im thinking i want to go out since all of my crashes have been clipping trees and feeling like im getting sucked in deeper, makes sense now.
@ChrisRosser
3 жыл бұрын
You need to change ESC settings too. JB has a good video on it I think.
@lanxang173
3 жыл бұрын
Switch your props around, change your ESCs to the opposite direction (normal > reversed ; reversed > normal) , and select the motors reversed option in Betaflight. That's all you need to do. On whoops slide tweezers between the motor and prop to get them off easily.
@Dragonewiz
3 жыл бұрын
Can I just revers the prop config in bataflight to try props out????
@ChrisRosser
3 жыл бұрын
No you'll need to change your ESC settings.kzitem.info/news/bejne/lGirtn14soWYn6g
@TomRolfson
3 жыл бұрын
Props In = No More Spin (You're done) Props Out = You'll Bounce About (but keep on flying).
@noobFPV
3 жыл бұрын
That is weakest argument. When you fly you are more likely to hit something sideways, cause you can actually see in front of drone.
@qpmkro
3 жыл бұрын
Props out always since i first changed my props
@stevend12
3 жыл бұрын
I have changed to prop out but straight away I got more prop wash. Can this happen, should I just revert back or tune it out.
@spikester
3 жыл бұрын
What ESC? Stop running 48khz if its blheli_S and use 24khz instead, or if you have blheli_32 the new variable pwm 24-48khz, its better to start there instead of trying to tune it out of the controller if thats the cause.
@stevend12
3 жыл бұрын
@@spikester it’s a matek f722. I am running the 24-48 variable. It was night and day difference between props in and out, I wondering if it was turbulence from the frame arms now the leading and trailing edge of the props have been reversed. I don’t really want to change too many fc/esc settings if the fault is a design issue. Cheers
@spikester
3 жыл бұрын
@@stevend12 Excess frame vibration hitting the gyro, you have all your bases covered on the ESC. Indeed I too seen big differences between props in vs out, especially with how frames can resonate.
@SukSukulent
3 жыл бұрын
2:30 Bzzz Bzzz!
@ChrisRosser
3 жыл бұрын
Battery finished charging!
@kampkrieger
3 жыл бұрын
i think your analysis of the authority is faulty. because what you do in a coordinated turn is not left yaw and roll but left yaw roll plus pitching up. and that puts even more load on the front motors
@ChrisRosser
3 жыл бұрын
Thanks for your comment. It's well understood that for craft with less authority such as tiny whoops props out does confer a benefit. In a coordinated pylon turn pitch remains constant, in fact you typically pitch down slightly to accelerate out of the turn. I think you only pitch up if you are trying to turn like a fixed wing?
@kampkrieger
3 жыл бұрын
@@ChrisRosser i thought you speak about 5"ish free style or racer quads. if you look at the stick movements (e.g. bardwells videos) we always pich up when doing turns in acro mode. you could also look into the log as u do a coordinated turn and analyse what is the command input. another thought that i have is how much work is to be done to accomplish the turns, i would guess the effort for yaw is higher than the other axis
@DudeAteMyHomework
3 жыл бұрын
if props in gives you better control, but makes the front motors work harder, what about if you have a camera mounted on the front and a forward shifted cg? would the front motors have to work twice as hard?
@nickgreenemail
3 жыл бұрын
Fun theory but specifically for racing I have the impression (I could be wrong) all top racers are running props in.. they do a lot of testing, measurable by lap times, so I’d be surprised they’re holding a wrong belief for so long - not to say it’s impossible. Any thoughts on this and any idea as to whether my assumption (that they’re all props in) is wrong? - it would be fun to test this hypothesis with a consistent racer and also measure battery life
@ChrisRosser
3 жыл бұрын
I'm not a racer. But I wonder if that's true and how much of it is to do with what the default in BF is.
@mlentsch
Жыл бұрын
Well, then... why in Christ is the betaflight default "props in"???????
@kwadkenstine4988
3 жыл бұрын
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.
@thecakeisalie7070
3 жыл бұрын
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.
@jimmynature7661
3 жыл бұрын
You convinced me to switch to props out on all my kwads. I know what I'm doing tomorrow! Great info, Chris!!
@ChrisRosser
3 жыл бұрын
Go for it! Hopefully you feel an improvement!
@MrShutterBug
3 жыл бұрын
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
3 жыл бұрын
Very interesting. I'll add it to my list of science videos and take a deep dive look.
@Ugly_Baby_Gaming
3 жыл бұрын
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
3 жыл бұрын
Very interested in this as well.
@Ugly_Baby_Gaming
3 жыл бұрын
@@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
3 жыл бұрын
@@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
@srossi88
3 жыл бұрын
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.
@anvyfpv
3 жыл бұрын
So, why are Props IN default in all firmware? :D
@ChrisRosser
3 жыл бұрын
I think its just historical, but maybe I'm wrong?
@harryhalfmoon
3 жыл бұрын
@@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).
@stevo43068
3 жыл бұрын
This raises the question, why is the default "props-in"?
@ChrisBe88
3 жыл бұрын
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
3 жыл бұрын
Absolutely! Another advantage of props out.
@robinfpv4858
3 жыл бұрын
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
3 жыл бұрын
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
3 жыл бұрын
I'm sure I remember a video from a long time ago where JB said props out was better
@repairengineer
3 жыл бұрын
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.
@overbese
3 жыл бұрын
I am a prop outy. I was hoping you would answer why betaflight default is in, & so many prebuilts come as innys.
@ChrisRosser
3 жыл бұрын
I wish I knew too!
@scooby3133
3 жыл бұрын
That made me think I was doing it wrong. Like, it's default for a reason, right?
@onemanmob6756
3 жыл бұрын
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
3 жыл бұрын
When I started looking into this I though it would be more balanced too!
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