Propellers 

I just became aware of the relationship between the hypetrain race quads' propellers disc radius, disc radius of an electric saw blade, and fidget spinner toy disc radius - Thank you so very much. Outstanding Video - You may not realize it but you helped to save my life.

I think we need an episode where you guys race quads against the top gear guys in cars... make it happen!

Ok, so I know this is a pretty old video, but there is something you guys got wrong in this video around the 10:00 point when you talked about hang time. You're right that if you're throttled up and pointed downwards, more thrust equals less hang time, but whenever you're throttled down then the speed you fall at is dependent on the prop shape. The air will start to spin the props instead of the motors, assuming you're throttled down. This is what helicopter pilots call autorotating. If you have a high disk space, then more air is hitting your prop as you fall, and more energy is dissipating into rotating the propeller, making your prop act kind of like a parachute. So a higher blade number or a lower pitch will give you more hang time, because it gives a higher disk space. Btw, I absolutely love you guys, I don't mean to insult you or anything, I just know this is something a lot of people forget about. I also know you guys have more experience flying quads than I probably ever will, so I'm perfectly happy to accept that I'm completely wrong if somebody explains it to me. Thank you guys for making these awesome videos and helping people learn and get interested in this hobby, you do a great job, keep it up!

Awesome video. I'm a noobie and you guys just made a lot people's prop choices suddenly make sense to me!

I still have a big bag of Gemfan 5x3 props if anybody wants them. They are great for mixing epoxy and stuff like that.

You guys gotta make update videos like these!!! These type of vids are what get people into the hobby!!

Chad tried to get me to blow up my thrust stand last night testing these props :) the HQ 5x4x3 pulled almosgt 1300grams!

Thank you for bringing back the original intro! It's way better. (:

I love it when you elaborate on the technicality and still keep it understandable. Best review of the series for me. Thanks a lot guys!

Great episode guys. Very down to earth and full of information.

seriously 1 of the most informational. vidz out.. it answered all my questions. thank guyz.

Thanks guys, I've recently changed my HQ 5045bn for 5040 3 blades and I won't go back now! Love these props, really enough speed for me and great response, and a real advantage I discovered is that even if you broke a blade with touching a branch you can still fly and go home and don't have to walk and search the quad....ok....the noise is terrible but the quad still fly.... ;-)

great vid guys. I went back to a 5x4 from a 5x4.5 and dumped the bull nose all together. flight time is way better now. and both quads handle great. Thanks

Excellent analysis and comparison to car physics. The knowledgeable insights and personal experiences supporting quad dynamics is unrivaled in RU-vid. Great episode Team RR!

Finally! Everything (almost anyways) in one place! This is the type of video that helps promote interest in our hobby from noobs to ace pilots alike. Well done RR.

Best video on props so far, to the point and very easy to understand. Been thinking about trying some tri's and bullnoose, so this really pointed me in the right direction!

Brilliant run through guys thanks. Trying to encompass the theory of propeller efficiency in 15mins takes some doing. The helicopter designers have all been through this process. If you equate the type of flying you want to do with a helicopter you will find that machine has the appropriate rotor design already. I.e. Fast, nimble machine, look at a MD500e with 5 short blades. Pro's = Small, high loading disc area, but really biting hard, using those 5 blades to max effect for rapid/agile response. Cons = High fuel consumption/reduced endurance. Slow, cruiser machine, look at Bell jetranger with 2 longer blades. Pro's = Very efficient, larger disc area with lower loading. Low fuel consumption/increased endurance. Cons = Reduced responsiveness, require more clearance from fuselage. The key difference with multirotor blades is their requirement to accelerate and decelerate rapidly to generate the torque for Yaw as well as the asymmetric lift for Roll (all at the same bewildering time!!) The glaring next step would be variable pitch blades which would transform performance. That would be like going from riding a bike with one fixed 3rd gear to a 10 speed racer. fast at accelerating (fine pitch) to high speed blitzer (coarse pitch). BIG problem with that is added complexity and much MUCH more expensive replacement costs when you hit that tree or race pylon etc!! Please do more of these talk through's and you guys should link to your store and sell these blades so we can support your Rotor Riot posts.

Really good video, maybe the best one! Everyone that builds/flies drones should watch this!

Great info . Thanks Chad and Steele. I flew a gimp-fan tri a while back.... you could hear the blades flexing when you pumped it into a 180° corner and jammed the throttle on to get moving forwards again. I took them off straight away. DAL props all the way for me. 6x4.5 on my robocat with 2206 1900kv... heavier quad and 5x4.5x3 on my qav210 with rs2205 2300kv pocket rocket. Cheers guys!

Thanks for the prop class. Students totally got it and now want to test props thanks for the class motivation.

Thanks for answering every question (and then some!) I've had about props in 15 minutes. I can now stop sifting through pages upon pages of forum posts and use this as my prop bible. Cheers.

awwwwww... Steele in 2016... nostalgia hitting

Sweet vid, makes it simple. Would like to see you guys discuss your FPV setups some time - What cams & VTxs you use, how many MW, which antennas you use & why.

Very comprehensive review of props. Thanks guys.

Nice work guys, love the analogies Chad and Steele use, as specially the feel

excellent explanation guys, this explained for in a few minutes than most of my online research. Now you should do a video about prop materials.

Thanks guys, I am just about to start tuning my quad for the first time and your video is a big help. May have to watch it several more times to under stand more about tuning. Cheers

Love the car transmission analogy for prop pitch. I understand the trade-offs now.

This channel is my heaven

You guys should go over your process for tuning PID's and rates. I know that would help a lot of newer pilots like myself, great job guys!

Thanks for the information guys. As someone new to fpv this helps tons.

Thank you very much, I learned a lot here! keep up the good work!

I love the car analogy with the gearing. Perfect explanation Chad!

Awesome video! It may have been worth while mentioning prop balancing though! It reduces vibrations, and increases efficiency - RPM for those of you curious!

Very good video on props. I'm just getting started after flying a Hubsan X4 and a Phantom 4 for a few months, and I really didn't understand the differences between prop sizes, blade count and pitch. Subscribed! I just started flying a Storm SRD250 with 6" props and while I'm still learning how to control it at high speeds, I can really tell that it's a great quad. Hopefully soon, I'll be able to really get the most out of it. Great channel, guys!

Thank you for covering props!

Very informative and one of the best videos you've done.

A spinning prop with more blades will likely act more like a parachute, hence why when cornering it feels more locked in rather than drifting around. Up-side-down hang time could possibly be improved regardless of blade direction simply cause the 4 blade is spinning and is providing more resistance from the air thats bumping into it as it falls.. The difference may not be much, but possibly some people are noticing it especially when compared to a 2 blade flying.

Thanks very much fellas, it answered a lot of my queries, CHEERS👍🏽

great descriptions for the different types and handling and uses. technical stuff and bench tests work, but real world applications are good to know too. Thanks!

Just want to say thank you for doing these vids. They really helps with my knowledge base and educates me on the different aspects and science behind what each piece does. Also through the videos I have learned what I'm doing wrong like 5 DAL bull nose blades with a Glacier 45C 1300mAh 3S 11.1V LiPo Battery which is too small from what I understand from the video. so time for some different props.

great episode, we want more like these!

Awesome video. Thx. Other ideas: matching props to motors, ESCs, batteries. Quad sizes vs props, motors, ESCs. More pid tuning vids. Frame crash strength consideration/what to look for. Fpv setups.

You guys are AWESOME! I love all your videos and this one taught me more than I learned in High School. Ha!

Thanks for all the advice guys It has been really helpful

Educational. Thanks for this episode!

great tuturial guys helps a lot , its a mine field, hq 5x4x3 for me, tried 5x4x4 feels very locked just missing something that the triblades give.

Props to you guys. This video is fantastic!

thanks for clearing that up

Great video as always guys, the info on props was very informative. One suggestion - 90% of my RU-vid viewing is done on an animation/editing suite at work during lunch breaks or render sessions... the title sequence is quite loud (I have to turn the RU-vid slider below 25%) but the actual segment is very low (I turned my slider to 100%). This goes for a lot of RR clips that are "in studio." Flite Test has a similar issue, but not near as bad. A show suggestion - I'm really just starting out in FPV (but have 2 years experience flying quads) and the "proximity" flying (like a number of StingerSwarm's videos) is more interesting to me than "trick" flying... how about an episode on that? Maybe with some tips? Awesome show, guys!

Great video guys I really appreciate the help and dedication to the hobby!!!!

Great and informative video, learnt a lot about props from this!

I would love to see an episode on PID's starting with a stock Cleanflight setup on a Naze32 board and showing how the guys would tune it to get the locked in, crisp, nimble and fast machines that they fly.

THANKS GUYS !

thanks learnt a lot. i was wondering why people choose to use 4' props and this answered my question

LOL, I had to learn tuning my quad on gemfan 5030s ABS. I kept getting frustrated i couldn't get it locked in. Then I got some real props and figured out why.

One crucial thing you guys didn't mention was prop brands...lol, you only talked about HQ props, (except for steele talking about the GemFans), why no mention of DAL "indestructible" props? or carbon fiber props? I myself use HQ 5x4x3 and 5x4x4 as well as DAL indestructible 5x4x3 (for their price/ durability compared to HQs) You should've mentioned this stuff. And why no links to any of these props in the description? Newbies will have no idea what props you guys are talking about, and where the best place to buy them is.

Best episode so far guys. Keep up the good work!

A vid on how you go about Tuning PIDS would help a lot of people out!!!

Thank you guys so much for this...as a noob..this has been on my mind for awhile...cheers:)

Loving your videos guys, thanks for educating us all in this great sport. I'm really curious about your battery habits, how many you have, do you have different batteries for racing and practicing, how many cycles do you normally get, do you break your batteries in.... would love to see a video on this. Keep up the good work!

I think you guys are great! SUPER helpful! Thanks soo much!

A very insightful video guys!

I love seeing that basement again! Just like the old times from FliteTest :)

Learnt a lot there - thanks. I'm hooked on the speed so I'll not bother with the four blade tris.

Nice explanation guys!!! Very useful!!!

great vid.. I've had a lot of luck with the new gemfan 5050 triprops & my 1300mah lipos still have long flight times

I guess hobbyist and engineers speak a different language. Still good to hear the felt response of the props. One thing to consider though, is matching motors, props, and the lead afforded by the control loops. Lets co sider just thrust. A motor with a torque a back emf at a give rpm will match a prop at a drag torque, resulting in a steady state rpm at a given throttle setting. A 4x40 prop on a motor and battery at a given throttle might be 6000 rpm, when a 6x40 will be 3000 because the prop produces a higher drag torque at a lower rpm. Its also not just the diameter, but also the pitch, camber, and wet area of the rotor. In general you should match motors, props, and baterries. Now onto how they feel. A snappy response is dictated by how fast a refernece signal ca be tracked by a system. Now on a quad there are several systems to consider. Propulsion. Given a combo batt, motor, and prop there is going to be an associated delay between how fast a given throttle (pwm->esc>voltage) will be tracked and reach steady state. Ignoring transient aerodynamics, this value is almost entirely dictated by three parameters, prop moment of enertia, motor time constant, and prop drag torque. The more mass further away from the axis of rotation, the more torque is required to speed or slow down the prop. The more powerfull the motor and lighter the bell of the motor, the more torque is on hand. And finally, the more lift a prop produces and the faster it spins, the more drag is produced. One other source to mention is vibration caused by unbalanced torques. A two bladed prop is less stable then three bladed prop, and by stable i mean that if you look at the physics of the eurler cross products during a rotation of the quad crossed with the rotation of the prop, a term ca cels out in the three prop case, but not the 2 prop case. This causes a vibration in the motor shaft, which is picked up by the imu. So ok, the reference signal gets lagged by the low pass nature of the motor rotor combo, but how is that reference made anway. Well worki g back, by the esc. The faster the esc can transfer data, the better more often the motor can try to track the refefence. The typical servo pwm runs at 50Hz, with a pusle of 1-2ms every 20ms. Shitty really for a quad. Instead we try to aim for a rate of 1000Hz, which can be accomplished with newer protocols like Onshot125, which can be sent around 2000Hz. This allows for a much snappeir resp9nse of the throttle and allows the controler to correct more often. The controller now does two things. It tracks a reference command via feedback, such as angular rate or Brian-Tait angle (will people please stop calling them euler angles!), aka roll-pitch-yaw and it introduces lead in the form of a new refernece signal to the motors, which compensates for the slow nature of the motor, prop combo. For iinstance a motor prop I am using has a time constant of .07 seconds, but i want a rate command which has a timeconstant of .02 seconds, what do i do? Simply put i design an algorithm to sends a faster command to the motor briefly and then slow it down in a simular fashion. This can be done with a PD controller or PID if you want zero steady state. How this can be designed is by examing the frquency content of the motors and props as well as the moments of ernertia of the entire quad. I did this and designed a lag lead network which outpreformed a manual pd co troller. It is scary how fast it can flip. The point is the felt perfomance is a combination of many things, and its simply not just due to the surface area of the prop, though that is something to consider. I can make large quad rolling on 8 inch props feel like a 250 if i can design an aggressive enough controller given that the sensor noise is low enough and the motors dont saturate.

Wow! Great info. Thanks guys!

Thanks mates! that will save me money and time !

Great video Guys very informative . Keep em coming

I also see the force multiplier or electromotive force in the hypetrain race quad motors and the dewalt electric saw blade - Thank you.

great vid guys thanks for the break down.

Really good episode, cheers guys

Great vid guys. Well explained.

Guys thanks for the review very informative, been playing around with different prop sizes 2 blade vs. 3 and 4 blade. You did a great job explaining the differences 5’ tri blades works best for me, now I know why.

Hangtime counter argument: If you flip upside down and bring throttle down to low, the increased area of a triblade/quadblade adds more drag as the quad starts to fall and that means that it hangs a bit better with larger area prop That is why some fixed wing ESCs have braking built in, a windmilling prop acts as an airbrake

Best props for beginners I've found so far are the King Kong props. They will flex in a crash but not break meaning that it isn't going to bend your motor shafts like the DALs will. Inverted into the ground only slightly bent the prop, just bent it back and went back in the air. Same story with hitting another quad head on and a soccer goal at 75% throttle; they just don't care.

Well explained guys thanks

I love your channel, enjoy every episode. At the moment i am just flying planes, but today is my birthday and well see if i will fly a multirotor in a few day. As a student i have not the highest Budget but I do what i can to enjoy the hobby. You and flitetest help me at this alot. +Rotor Riot ;)

Thanks guys ! Very helpful !

I prefer crashing, for a beginner, it REALLY helps you learn more about the ins and outs

props for that atom reference. the kit car is my dream.

great work on this episode guys! very informative! the information was presented well.

you guys are always informative an fun to watch. keep up the good work. ✌

OK that's props...Thank You!! How about what spins them?? Motors; sizes, wire gauge, number of turns in the windings, weights vs power. Basically the SWEET SPOT motor for what you guys do. There are a ton of manufacturers and price tags, just curious as to what you think is the ideal motor for each flying style that you were talking about with the props... Tall order??? Thank You !! Love this channel

Great vid guys thanks very useful! I would also like see a vid on PID's and also a talk through on some of the tricks you pull off in the air. Maybe a slo mo with stick controls in view so we can get a feel for what your doing. Cheers

Are you guys going to talk about hang time and how to practice it, and what you are doing to do it, a how to style vid?

Great video!! Very helpful, you are doing a great job. Btw from my personal experience, harder the props more damage to the motor durring a crash. I used sone Gemfan 50x46x2 BN and bent one of my motor shaft...

Great show. I knew I liked the 5x4x4 for the corners, top speed isn't that important to me flying acro. Shows like these will get the hardcore FPV views, we need shows on motor size, ESCs, PID tuning . . . ;)

Really useful! Thank you very much!

I think when people refer to hang time it's when you do a fast climb out and shut the throttle off. The more blades the more the quad will 'hang' and float down slower.

Think of them (props) as "little wings" what you are doing is increasing the wing area and increasing the amount of "lift". Trade off is, more lift (or area) = more drag or load on the batts and hotter motors, if you go to 3 blade, watch your flight times and refigure them.

very informative guys. can you do an episode on matching prop to motor to esc to battery please

I had some 5" 3 blade bull nose props.. They were sick thrust. 4.5 pitch. Nasty. I went to a dal 3 blad prop, same pitch.. Flight time about the same. bull nose was less, not by much. But the bull nose had crazy thrust. I am going to pick up some more of those... Although I like the fact that Dal props are tuff as hell.

Thanks for the info! I'd love to see a video about minimizing latency (fpv video and Tx input/response).

Hi guys, nice vid but i do have my doubts: 1) You say a a bigger prop will spin up slower. The way i interpret this is: You got more power with a bigger prop, but your not gonna get it as fast as a smaller prop. Like horse power vs torque. Huge engine provide much torque, but a F1 car only has a 1.8l engine that goes up to crazy RPM real fast. This is in my opponion because of the dead weight of the prop itself. That phew extra grams you got to spin around at 30k rpm make it spin up slower, but at the same RPM a bigger prop generates more thrust. My point is that while BN props provide more thrust because of the extra surface area, they are less efficient as their 'not cut' counterparts because they spin faster because of the reduced weight. A faster spinning prop will always be less efficient, because the parallel drag you create just by spinning it (by parallel drag i mean the drag created for example by a prop without any pitch). Another thing is the propwash: An extra blade in a 3 blade will not cut through clean air, instead it moves air thats allready going crazy because of the other blades making it overal less efficient to bigger props with equivalent surface area. The fact that a 4 blade will do better around corners because the reversed airflow: When you're moving in the opposite direction of the pitch angle i think the 4 blade will catch more air, in which case surface area seems more import then a slight change in pitch?

I'd love to see an episode on FPV goggles and mods. Charpu has some interesting mods on his which I assume is HD downlink gear. I've also noticed gold bar/bars on some of your receiver bay doors. I'd love to hear your guy's thoughts on goggle models, antennas, and mods. EDIT - Maybe even just an episode on the gear/mods that each of you guys run and like.

Thanks guys for the explanation it helps 👍😎✌🏼️

Thanks Guys very informative !