The fact that you incorporate actual science instead of "Oh, I flew this one, then that one, and then I liked this one better." Well done mate.

I’d love to see an updated take on this with the new wave of all these 5.1 props like 51433, 51466, 51477, etc.

Bardwell sent me over to check your channel out, really glad that he did. Being an ex aircraft and helicopter mechanic, I guess that from my technical education required to get my license, a lot of the principles that you explain seem to be common knowledge, but that is only because of my own education. You did a great job of explaining a uncommon topic! Ain’t no perfect prop for all conditions, you have to choose the one that fits your flying parameters.

How much do I like your videos? I watch them twice. They are so full of great technical analysis that I pick up details I missed the first time through. Keep it up!

Love this, Looking forward to the next load of knowledge you can share with us. Keep it up !!

This is insanely good content. Learned more about props from this video than an entire course in aerodynamics at uni! Your explanations are great, thanks for taking your time to make these videos!

Good video. Appreciate your hard work in making such quality content.

Thank you very much for this video and your scientific analyses. I have been waiting for discussions like this in FPV. I look forward to all of your future content.

G'WeekenD Mr. Thanks 4 everything U do 4 this great community. I really enjoy your content, takeCare mate

I learned something today! Great video, thanks for uploading!

This video was fantastic. Thank you for doing this.

Your channel has given me a while new excitement for drones, I'm now extremely interested in the building and perfecting of the quad to squeeze performance. Before I couldn't digest it all, but giving us an understanding in more understandable terms will allow me to further delve in

Again a really good video!

If my algebra teacher would talk in the same interesting way, I would graduate from high school with A+ Just found why need to decrease kv, going to 6" and higher diameter props. I knew before that I had to do this, but now I know why :) I didn't even think about the speed of the propeller tip before. Thank a lot! You doing great job!!

This content is awesome kabab fpv had a video on the babyhawk 2 hd and had talked about how it’s frame resonance was really good then bardwell talked about it now I can’t stop thinking about this is awesome stuff you are doing !!

thanks Chris, very informative content

Thank you this helps tremendously!! Your'e video's are very educational I appreciate the knowledge!

Brilliant! I really like the academic approach! Well done!

Thank you for sharing so useful information! Keep on going!

At last, I understand prop wash, your videos are soooo good. Thank you so much. Having the equations and their explanations to understand the physical phenomenons is absolutely marvelous.

I've been here from day #1, and I don't regret it. I love how it's nothing but straight information. Keep up the the explanations coming, it's always interesting

*Chris Rosser* 💯 🏆 🥇 Щиро дякую за просвітницьку 🧑‍🔧🔬🧠✨ діяльність, дуже корисно!

Excellent work. Very informative video. Keep it up

Very excited to watch as your channel inevitably grows tremendously. You combine some of my favorite aspects of the likes of Joshua Bardwell and KababFPV. Please keep up the good work because I definitely learned a lot and enjoyed every second of this video. Also, I literally checked to see if you had a review of the Glide frame and what a coincidence that it's your next video

So detailed and complete, I love it!

Great content.

Awesome information Sir

I finally understand why all the top pilots use low pitch props for freestyle and what I've been doing wrong with my own prop choices. Thank you!

The man Chris does it once more...outstanding vid bruh

Now this is CONTENT!!!!💯👍 My only mistake is that I didn't find out about Chris until recently!!!! When the Yoda of fpv had his quad filter set by Chris and absolutely loved it I was like ok.....I need to find this Chris guy 🤣 I subbed immediately after watching the first vid I saw....just great information all around man✌....PS.....YODA IS JB 😁

I was scouring the internet for equations to solve for the right props, and I have FINALLY FOUND IT. also I'm so glad I took AP physics

dude you are my new favorite person, thank you!

Great content for some one luke me who wants to understand everything thanks Chris !

Damn. You posted this just after I passed my canadian rpas exam. Stall mechanics was one of the questions!

your videos pushed me to the other side of peak on dunning-kruger curve. thank you.

Some great content dude

Great info. Thank you!

I feel like this is a very expensive lesson for free. Amazing level of detail here in a science I don't know jack about

I can only imagine a prop hitting 1.0 Mach and hearing a bang as a trail of fire burning on a road is all that is left as the drone travels back to the future.

Congrats on 10k subs today! I was one of the latest 😎👍 I only comment here because this is the video I was watching when I noticed the change from "9.99k" to "10k." Your almost purely scientific approach lifts the fog of uncertainty in several aspects of quad build considerations. I fully agree with the rest of these comments saying it was great to find you and learn so much more than expected! Keep it coming!

thanks the video clarified what prop should I use thanks a lot

both your disk loading and prop tip speed lessons helped me 1) verify that someone's 3.5" digital toothpick actually matches kabab's analog 3" toothpick characteristics, and 2) how to calculate the ideal and maximum motor output % to make my over-kv motors match that same config. you are a legend for bringing sanity and safety to this hobby

Its really helping

Very informative videos.

Best FPV video I have ever seen, beats even JB in my opninion. Do more please!!

Very useful, thanks!

The moral of the story is that 5043 props are all that you ever need as it seems to strike the ideal balance.

very well done video. i like the maths and thinking.... bravo!!!!

So much insight! Thank you. I have always thought that props with more pitch should be more efficient. Many youtubers told otherwise and it really confused me.

So where my physics teacher ears are burning. Because I am set here like WHY DID I NOT LISTEN IN CLASS!!!!. Good info really putting this with your motor video I have a better feeling about the props I am picking for my rigs. Instead of just well so and so use this let's see.

i have a big box with 30 packs of differents new props (for test only) and when i have a new quad, i take the box to test and know for the quad i have buid what props are the best. thank you for this video ;)

this was a very useful 18+ minutes of my life, thank you! now choosing a new props would be much less of intuition/reviewers influence and much more of understanding of physical processes which make quadcopter fly. subscribed!

yes excelent video thank u.

Hi Chris- love the scientific approach- would be really great to see how theory stood up to practice by setting up a double blind trial with some experienced pilots - suspect it would be difficult to get sufficient numbers for a significant result though

Really good information thanks 👍😎

The high pitch for lr was a big ah ha momemnt for me. Thanks man.

As a scientist and also a pilot... FOUR THUMBS UP for you my man

This justifies my findings in my prop reviews.

This series of videos is amazing. I have some questions, do these same pitch recommendations apply to all propeller diameters?, for example 3-4 in; and what would be the best propeller for a cinewhoop to get the maximum flight time?

(I really wish the x and y axis where labeled in the 'prop tip speed efficiency' graph😬) Great content Chris! Thank you for the educational material.

Awesome

Thanks - helpfull

thumbs up new sub, thanks for sharing

awesome video. I just recently went from a 5135 that came with my nazgul 5 and went to a 5043 and I was noticing I was having trouble getting it to float over things while trying to split s over them andbai could hear it grabbing more in the maneuver this video really helped me understand why it's doing that. What do you think of the really low pitch prop that it came with. When I look them up it says the pitch is 3.5

The video, and many of his other videos are marked with "FPV", however they apply more broadly; namely any fixed pitch electric multirotor. He owns FPV "vehicles" and operates them, and he choses to cover the science behind these vehicles for the benefit of us all. but it should apply wholly to any fixed pitch electric multirotor. Most of his videos probably also apply to some VTOL plane configurations.

I would really love a video about cinewhoops. The trends are covering the actual data. The Shendrones Squirt is supposed to benefit from a "duct effect" (and I feel like it flies really bad). Everyone is jumping on the "Slammed Squirt" trend and getting rid of the ducts. Who is right ? Meanwhile, HQprop is making a 6-blade and now 8-blade 3" prop. What's the science behind these choices ? I'm using 6-blade and it feels alright, but it's supposed to be quite inefficient for a quad that already has a big disadvantage in weight to power ratio.

Thanks for the insights. I though do not exacly buy into your concrete prop spec recommendation. I guess that also heavily depends on the prop manufacturer and how they form the tip ends. So as relative recommendations in the line of one manufacturer, I do buy into this. For freestyle imho the compromise is that you need "punch" and you have to deal with all this adverse flow conditions. Most freestyle videos are so appealing because there is smoothness and flow interrupted by phases of hard punchs. But certainly going for the most high-pitch prop is not the right thing to do.

Nearly every time I try a new prop I think what a wonderful prop. Everything from a 3" pitch to a 4.9" pitch. I even like the 5.2" pitch but I don't use those because I get about half the flight time. I don't think I'm good enough yet to tell much difference between props.

Great content! It got me thinking though, what if one would (theoretically) construct a prop that utilizes centrifugal force to alter the pitch slightly? Think of how a CVT system works with weights and ramps/rollers.. Would it be possible? Would there be benefits to reap from doing this? And yeah, it would likely not be suitable for a 5" prop for rigidity and durability reasons.. Maybe this is already a thing, I haven't read anything on the subject, but this video just had me thinking about how it could be done.

Thanks.

I have a cinebot 30 any suggestions for different props mostly recreational flying and I love the science behind what you do koodos to you

Another great presentation. I've been thinking about pitch vs inflow speed with airplane variable-pitch propellers in mind. Everything makes sense except the efficiency up to 8 degrees (or 16?) and how that applies to 5" long range propellers with pitches as low as 25. Should we be trying something around 30-35, or even higher? I have ran across people getting surprising efficiency out of very high pitched props. Can't wait for the Glide analysis, and hoping You can get a Fouride in at some point.

I was thinking about this more, do you know if the prop flex has any effect? These fpv props are quite flexible, I presume at a certain disk load the majority of the flex will have occurred and have little impact. I wonder if there is excessive flex at a certain low load threshold.

Once again you have put out some very useful information that will help us all build and design better flying quads. Your points are clear and concise and understandable for even people like me with no engineering background. You more or less answered this in the video but how does weight factor in to prop selection for 5" freestyle quads? I have some that are in the mid 600g and others close to 725g AUW. Would the weight difference lead to choosing different props all else being equal? Higher pitch on heavier quads? Thank you Chris!

I seen you briefly touched on the density of air. I am interested to see what your thoughts are on elevation and prop and pitch adjustments.

This is very very interesting and confirms and extends much of my own investigations. I have a question: how does the inflow velocity calculation change for fixed wing? Obviously the vin from the airspeed but do you need any additional factor to account for the inwash from the prop of can I just plug in airspeed in m/s?

Scientific approach which i like.

Haha dudes giving me a whole ass physics lesson, when all i wanna know what kinda props fit on my motors. ha.

Nice! I graduated as a lawyer, am building my first 4inch semi longrange sub 250gr. 4s quad, and after checking motor load charts, making some calculations I've diside to get 1507 2680kv motors with biblades 4024 on a throttle limited around 20% for LR, and 4023 triblades for freestyle.. (haven't seen less pitch im a triblades 4 inch props yet). Hope I'll get parts of it soon to complete, film, test and finaly have enough footage to start my channel. Ty for your sience, I'll be waiting for your frame, and hope we'll get a affordable shipping cost for it (Russian Pilot in the house 😉)

Hi! Can you help me, what config i should consider for 350g payload for my quad (like gopro as payload), bottom mount, battery on top? Thanks!

What if you had a 5” quad running 2806.5 motors but usied 5” 6 blade propellers? Would you get the trust performance of a 7” quad with tri-blades? Because the surface are of prop should actually be greater on the 5” hex blade. So would you be able to go with a bigger motor on a smaller quad and get similar performance? Better? Worse?

Love your content! I do have a question though: I think I’m comfortable with selecting a good blade count and pitch for a prop, but how would you go about selecting the correct prop size?

@Chris : Thanks for the useful videos . Wanted to bring up one question on props . Lets say while flying a 5 inch quad we tend to keep stock of multiple props . While all props will usually be 51 series , the pitch could vary . Now while flying lets assume we have a 5143 set on the quad and happen to break one or two of the front facing props . Now the only other set i have is a 5148 set . If we replace the front props with the 5148 does it cause problems . what happens if we end up mixing pitch of props mounted on a quad ? Is this a bad practice or something that never must be done ?

Hi Chris, this is reallly good. There is only question regarding AOA. The first diagram showed maximum efficiency at typically 4 degrees and stall at 16 degrees. However later you mentioned that efficiency will be improved all the way up to 16 degrees . Probably I missed something there.

Hello, thank you for the great video! My Question is: What about tiny whoops (e.g. Moblite 7 HDZero 1S). Is there a way to make it more efficient by changing the Gemfan 1610 2-Blatt Propeller?

Good person good answer.

This explains why I wasn't getting the top end performance for the Ethix peanut butter jelly props. I thought it was the weight, but it's likely my lower KV motors for 4S?

Another interesting thing to consider would be if "Floppy proppies" have an advantage in response time compared to their fixed counterparts. And if so is it quantifiable?

give us a cinewhoop already!! for a batteryless gopro >D ... also check the astrorc carbon fly 25 frame ,, diagonal frame.. keep the videos coming!!! and what controller should we use for maximum wall concrete penetration and dont failsafe and available >D

Would be great o see real life examples with known props and quads during a test? Great video.

I guess the only thing I still feel curious about; is props based around air density... I.E. how would a high pitch props performance be affected by flying at a mountaintop where air is thin? Also another incredible video mate. Doing the FPV God's work!

whats ideal to optimize in-ground effect hover and out-of-ground effect hover?

What Prop would you recommend for a 4s 7“ build (2807 1700kv motors, 540g dry weight)? I‘m not sure if 1700kv is low or high kv for a 4s 7“. I‘m looking for the longest possible flight times, so very low Amp draw

Okay I'm late to the game but everyone says you're the man to go to for facts. And I can't really find any good factual information on whether if the stock props or the prop adapters and a different type of aftermarket prop is better on the DJI fpv.?? It just seems like to me if you add the adapters and a lighter smaller prop than it really is being counterproductive and adding a smaller pop to spin off faster... Any advice would be greatly helpful

Hello sr. Dji FPV drone is 795grams, 1700kv motor and the stock props are 5328. I have the aikon adapter and want to put some aftermarket props, Wich one could recommend me? I want to avoid the prop wash that this drone have. Thanks and have a nice day

So one single blade on the props if it’s skinnier with wise than the stock ones what effect will it have

Chris, these slides are available somewhere so we could quickly refer to your graphs when needed? A blog or server perhaps?

What happens if you keep pushing kv for a given setup? Hot motors? Lipo not being able to provide the amps? What will be your bottleneck/performance issue?

How might the number of blades on a prop affect the overall vibration characteristics of a multicopter? The presence of load changes on the arms from the downwash of each prop blade makes me think that a certain number of blades might perform better or worse for a given frame design.

Hi, I asked myself all the time how to think about this on my Cinewhoop. I just finished watching your new video about ducts, and I have a squirt V2 at home. Also I am just designing my own "megas-quirt", that can handle 3.5" (89mm) props, as my Squirt is barely holding itself in the air with a Hero 8 and a 1300mAh 4s lipo. Now to my question: How do you think that multiple blades change the therory. By that I mean the 6- or 8-bladed HQ props, or the much steeper Gemfan D76 or sth like this. My testing tells me, that two props that both are called to have a pitch of 3 aren't really comparable, doesnt matter whitch size (3", 5", ...). In the cinewhoop-part also the diffrent blade-count makes everything even more uncompareable. I really have problems to compare a Gemfan D90 (3 bladed prop, pitch "3") to a HQ 89mmX8 (also pitch of "3") but they clearly are diffrent in their steppness-angle and will poth have very diffrent thrust. toothpick-class: Gemfan for example has a 3018-2 prop (biblade) and a 3016-3 (triblade), I also cant tell in this case which prop I could expect to have more thrust. The issue is, that we often dont have real numbers to calculate with or alternatively have simulation-values or static-bench test from the manufacture himself (1st hand). Sometimes I have the feeling, the manufacuters dont use the pitch-value to tell us how steep the balde is, rather to tell how much thrust they think the prop makes compared to their other props on the market. By adjusting the pitch value they use for marketing so they can put their props in somewhat of an order they make comparison for us pretty rough, and practically impossible to compare to other companies. Did/Do you think/feel the same as I do, or do you understand my problem? If so, do you have any idea how we could interpret these values we get from the manufactures, or do anything about it other than just buying a ton of props just to find out that 99% arent the ones we where looking for? Thank you so much for your videos, it is great to understand such topics in greater detail, love it, keep it up!