How to choose the right props for your quadcopter: FPV Freestyle, Racing, and Long Range 

Thank you, I try to take feel out of the equation a little bit because 1. I'm not a pro pilot 2. It's very subjective and can sometimes lead you down the wrong path for the right reasons or the right path for the wrong reasons!

Thank you! I have an advantage over your algebra teacher: FPV is more awesome than calculus 😎

@@ChrisRosser i was gonna say the same thing: you have interest in the subject. Changes everything haha

Thanks! I appreciate your support.

It is!!

Wow, thank you! I appreciate your positive support.

Glad it was helpful!

Glad you enjoyed it!

It depends a lot on how you fly but if you fly reasonably fast and are gentle with the throttle you can really benefit from a steeper pitch prop! Thank you for your comment 😁

Part of the reason for the confusion is that most pilots don't mean the same thing when they say "efficiency", as Chris does. When testing motors, efficiency means grams of thrust per watt of power. But when pilots talk about efficiency, they usually mean longer flight time. A lower pitch prop will usually give longer flight times all else being equal, because it makes less thrust and so it draws less power. Lower pitch props also load the motor less. This is especially true when talking about a high kv motor, which will need to draw more current to generate the torque to try to spin the higher-pitch prop at higher rpms. I think the effect of the prop loading down the motor is not taken into account when it's said that lower pitch props are more efficient. Rather, the motor is assumed to have infinite torque reserve, and so the motor's performance doesn't change as the prop changes. But real motors don't have infinite torque reserve. Take a 6S battery and a 1900kv motor and spin a Ethix S2 prop and a Gemfan 51499 on it. I think you'll find that the 51499 is less efficient in terms of grams per watt due to it heavily loading down the motor, and because at higher rpm you enter the stall condition that Chris discussed. But even if that turns out to be false, I'm 100% sure that you'll get longer flights on the S2, simply because it's making less thrust. And that's what lay-people usually mean when they say a prop is "more efficient".

@@JoshuaBardwell Totally agree. Most pilots mean flight time, when they say "efficient". I also think that manufacturers are partly to blame. Such as every motor is advertised as efficient, light, powerful, and easy to control.

You are so welcome!

Thank you! Will do!

Thanks so much! I hope you found it useful and enjoy the other videos 🤠

Thanks, will do! It's really nice of you to leave a positive comment 😁

I really appreciate the positive comment and can't wait to hear what you think of the analysis of the FPVCycle Glide Frame.

Thanks Vitroid! I really appreciate your support

You're welcome, we're all on the climb up the next slope now!

I was freestyling at 2700 kv 4s with 5042 props already though :p.

Thank you! Very excited to keep producing the videos 😁

Thank you for your wonderful comment. I'm not sure I'm quite at JBs level but I love that you are finding my videos valuable.

even Paweł Spychalski, if nothing else Chris does not say "basic-A-lly" (I pick on Paweł only because I have the same outrageous accent)

Glad I could help! Thanks for your support.

Glad you think so, thanks for your comment!

I'm glad to hear that, hopefully you'll find the perfect props for you more quickly now you know what to look for.

Happy to help!

Ducts are on my radar as another topic to apply some science to, I think you are right people need some more information on when and how to best use ducts to get the most from them and when to go with just prop guards.

Perfect! 😀Having both options on the Squirt and on a 3D printed frame, it will be easier to compare them with a bit more knowledge on the physics behind it.

Is the slammed squirt trend actually getting rid of the ducts? still looks like a duct to me, just a bit shorter... Anyhow Rosser has since made the duct video and I have just ordered a slammed squirt, I'm a little concerned that maybe I won't get the actual beneficial effect he described in the video from the slammed version, and maybe I should ask for a regular non slammed version. The slammed version looks nicer though 😅😅

@@definingslawek4731 It is actually different because it doesn't benefit from the "turbine" effect. Chris made a video about it if you want all the details : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7f2DZIC8a1k.html

@@LenordeFPV I'm told the slammed squirt still has ducts, and there's a video showing an increase in thrust with the duct versus without. Anyhow I ordered a slammed one and I hope that it wasn't the wrong choice vs the non slammed version. In OP's video on cine whoops he says the most interesting part of the ducts is not the extra thrust but how it makes it more stable and thus comfortable for flying slow proximity and Indoors and stuff

You're welcome!

Thanks for the support! 😁

@@ChrisRosser one of my group friends keep asking me if placement of VTX above Power Cables will affect the components from the VTX. I just simply says yes for micro magnetic field. Might be a good theme to cover, maybe?

Thank you! Cheers!

No worries, don't forget that throttle limit otherwise you might be tempted to use all that performance and kill your flight times.

Glad it was helpful! Hope this helps you to find your perfect props.

@@ChrisRosser it will for sure!

Thanks for the comment. I really appreciate that you watch and comment on every video 😁

@@ChrisRosser hey you’re producing some of the most interesting technical videos in the hobby that I’ve seen in a long time mate 👌 I have so many questions I would love to ask you, like the does putting seperate ESCs on the arms have any appreciable effect on resonance compared to using a 4in1?

I love it when theory aligns with experience!

You are correct, this can only be a guide, to try and help people know what type of prop might be right for them. Thanks for your comment!

As you increase AUW your inflow velocity in a hover is going to increase and so you might pick a steeper prop for more efficiency. If you do a lot of reverse flow moves that could affect propwash handling so another solution is to go up to a 5.1" or 5.5" if you can and keep a lower pitch.

@@ChrisRosser Thanks for taking the time to answer my question and that makes a lot of sense. I would like to see some more prop manufacturers make 5.5" props especially low pitch ones. I haven't seen any freestyle 5.5" props yet but would love to try some out for my heavier quad that can actually accommodate the 5.5 props (marmotte lol).

@@chibikaiju922 Actually have bought some 5.5" props (also for a Marmotte frame) but only had time to do arround 5 packs or so. I really like how stable they make my heavy quad (717g) and also they just made my marmotte the fastest quad I have, but my batteries hate them. My motors are so much more capable of pulling Amps (before max arrond 96A, now all the battery has to offer, arround 130A). That went that far, that I accidently had a sag (if you can call it like that) to 8.8V on my 4s-Lipo. I hadn't pulled to many mAh at that point, but just the gigantic, onholding load killed it. Just did a dive/half loop over a big tree and hat to catch it, and then the volage began to sag out, so I had to throttle even more, but that only resulted in more amps and so on, untill I hitted the ground (at 8.8V XD ). Okay, now back to the prop: It is definetly a little quieter at hover and also I can hover now at arround 7A, before it was arround 11A which i guess is pretty amazing, and also the normal flying takes a little less Amps, but as I said, when u punch, the motors just can work hader and pull more Amps. So there is just a benefit for me in that area. I had some problems with some pretty significant bounce-backs after fast flips and rolls, guess that will be mostly an issue of retuning the PIDs, but havent had time to look into it. All in all, I really would reccomend everyone that has a quad with 700g+ to just try a set of 5.5" props, I have bought these: HQProp Durable 5535. Also I bought some 5" props with 4 blades, havent had any time to test these, but I hoped to just get more surface area and maybe also a better flying quad when its rather in the heavy part for normal 5" 3baldes, but as I said that is just my hope and will be tested as soon as the weather here gets better. Hope I could help you, have fun ;^D

Typically the best way to combat elevation is to increase the chord length of the prop blade. Steeper pitch can hurt propwash handling.

The best efficiency should occur at the best lift to drag ratio of the prop which will depend on shape but is typically around 8 degrees (this is for a hover). Obviously inflow velocity affects the angle of attack so can get a little complicated. Once you start flying the drag of the quad and the inflow velocity due to your forward speed starts to matter. At high forward speeds a steeper pitch prop is probably going to give you more efficiency in g/W.

No you're awesome! Thanks buddy 😁

I like your positive comment. Thank you!

Thanks for the support and the great suggestion. 😁

@@ChrisRosser Thank you for the content! Next tuning a 7”? :-)

I'm hopeful that my frame will be globally available at a reasonable price! Good luck with your channel.

Hopefully this video has helped you decide what prop to pick for how you like to fly! 😁

At higher altitude the air is thinner so you will get less thrust. I think the best way to combat that without affecting any other parameters would be to use a prop with a longer chord or additional blades. If you change pitch you will affect the stall performance but additional pitch could be another way to get back some of the thrust you're losing due to the thinner air.

I would really appreciate a video relating to altitude. I fly freestyle and long range between 8,000 and 13,000' above sea level. I've enjoyed experimenting, but I also enjoy your videos, science, and experience

I know it will be a very general guide, considering all the lots of thing you have just explained. about different direction of the air flows ext ext. Thank you💪

I think that graph is in my motors video

@@ChrisRosser Hi, yes of course, I mean please add also the props, in order to have the exact position of them between stator volume and inch quad. Thanks

Thank you for the sub. It makes a huge difference when I speak with manufacturers regarding support for testing.

No worries!

I think you should be able to calculate inflow velocity using a momentum balance taking into account that the initial airspeed is not 0 as it is for a quad in hover.

Not really the chord length is much much less impactful than the pitch. A longer chord makes more thrust so you probably have lower rpms with it which will increase propwash. If you have set up dynamic idle that should really help.

@@ChrisRosser Thanks i will try!

I have a video on that! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-zY68Nf9Cobs.html

@Chris Rosser - the rule of thumb I've been using to calculate maximum tip tolerable RPM has been 38k RPM, in nominal cases, for 5". Thanks for that WarpDriveProps calculator tool, since I feel like doing the more simplistic calculations lose accuracy by the time I'm at 7", as I keep finding myself just over the limit on builds I have calculated to be marginal but within bounds (the good news being that throttle limits are easy to adjust downward).

I would add to this that I think manufacturers are designing props that don't require throttle expo or throttle limits because no-one is using these (except to run 2400KV motors on 6S). They are realising they need to reduce thrust to give pilots more control. If everyone tuned their feel using throttle expo I think we would see more props that are designed to get the most from our motors.