YAY! Awesome as always! I'm curious how the HQ 90mm 8 blade stacks up in testing to a 5" prop. I've been using them on my AOS 5" UL for a while to fly in places where the noise of a screaming 5" might be disruptive. While they certainly aren't as efficient, i've not felt i was lacking thrust over a 5" tri-blade, and they certainly seem much quieter. Of course, none of that is Science, just my impression when using them. :D

Another banger video chris thank you

Fascinating finds, Chris! Fantastic testing!!! 😃 Stay safe there with your family! 🖖😊

Great video Chris.

i’d really like to see open-air props from previous video directly compared (using the same motor) to the ducted fans

Great work Chris! As a person whose done duct design work, a large impact of designing proper ducts is the gap between duct and fan. You hit the nail in the coffin by stating that open air prop guards are much actual better "ducts". Keep up the great work.

those 8 blades are super fun on a 5" quad with 4S motors and a 6S lipo !! you lose in efficiency but the sound is awesome and the speed is not bad at all.

Nice test. Wished you tested the 4 inch props, because that is like the max size to build when we need to keep it under the 250g law.

Chris, insightful as always, I understand some stuff and you debunk the techy stuff with bar charts, that works for me. Your motors vid was great too, just cannot find the Shysters anyway on the planet!

Now I'm curious how much effect a smaller prop guard will have.. Thanks for your great videos

And of course, the 2 cinewhoop props I run are not tested. The HQProp D90x3 and HQProp D90x5. I feel like the D90x5 is one of the most efficient props I use, but it would have been nice to see hard data on that. I guess I can infer that from the data from the T90x3 and Gemfan 76x5? Maybe?

Great video! My experiment from last year is the same as what you've discussed. That's why I got rid of the duct. It makes the flight really bad.

Iflight nazgul are by far the best for whoop. You should try them

Hi Chris, it would be interesting to see the comparison between your straight ducts and "normal" (by normal I mean what is used on full sized ducted fans with bell mouths exploiting the coanda effect)? Best regards Sarah

Thank you

I’m glad I found your channel now but damn if only I had seen this before guessing on props for my CineBot…

Your measurements explain quite a lot what I got as a result in real life: My Beta FPV 95x gets only about half the flight time than my Cine25 despite having smaller props... but they basically run freely. It also feels better in flying and makes significantly less noise - both in volume and in subjective feel.

Unfortunately, this is missing the Gemfan D90-5, I really wanted to see how it compares to the HQ 89-8

Curious about what you said about auditory noise, HQ x8 props are some of the quietest sounding props I have flown on my 5-inch without ducts. The moment you put them in ducts they scream though.

So Chris, what props are recommended overall for cinematic cruise , fully ducted or inducted, with AOS cine35 which is quite a heavy build, even with O3 setup only. ? Thank you for all the content 🙏🏻

Well, love the video but i have a question regarding the ducts. The Bumblebee is not a pusher cinewhoop and the prop is pretty far up. I think there are some other people too, that fly a puller-cinewhoop. I would have loved to see a test for that too.

perhaps plot the thrust vs rpm graph in a log scale instead of linear scale. So it's easier to see the cross over points between different prop designs.

The duct lip (which yours havent got) is the source to an possible increase in lift. The lip works as a wing airfoil when properly implemented. Excellent video and sum up!

Curious what motor people are running with the 76 5 blade?

Okay so what about prop guards right at the edge of the props?

I run the Gemfan D76-5 without ducts on a little 3" i cut from leftover carbon sheets, man that prop does some interesting things when ran without ducts, I'm getting close to 5 minutes flight time with a full size hero 8 on it and a 850mAh 4S. It honestly surprised the hell out of me, because it really feels quick and responsive even with the insane overweight. Probably shouldn't talk about durability when ran without ducts though..

Idk how ducks exactly work but i imagine if you design them so they dont go that far over the prop where it would suck the air in they may still give a boost

As far as my experience goes, this should hold for 2-inch props, too. I've tried a couple of tri-blades [LDARC/KK 1935 {absolute crap}, HQ T2x2.5x3 {better, but still crap}], and a quad blade [LDARC/KK 2045 {kind of okay}], before landing on Gemfan D51s {perfection}. That design fits my LDARC/KK 1103 7800 kV motors and LDARC/KK 1.9" prop guards like it was meant to be there, delivering true duct performance. The blades are quiet and efficient; smack dab middling in performance - not too fast, and good with propwash.

I think this is why all the new ducted drones have slits or air holes in the ducts

I can't help but wonder if the ducted setup would do better as a puller, can you spin the motor/prop the opposite direction to test that?

Where’s the first video?

You tend to get better low-pressure thrust without a duct and better high-pressure thrust with one; the issue you are seeing here is you're comparing *static test values*, unducted props have good static thrust but lower high-end thrust, and ducted props generally have poor static thrust but better high-end thrust.

Ever since i tried gemfan 5 blades ive never went back to 3 blades for any of my cinewhoops. Flying indoors my cinelog35 felt heavy, sluggish and flew shorter with 3blades carrying 1500mah and full go pro. But with 5 blades it just flies better and much more efficient and even more efficient if you go lower kv. And theres barely any difference flying indoors or outdoors. I get 12mins of flight time no gp 1500mah and 10.5mins with full gp same batt

It would be interesting if you tested a proper duct with a flared opening and non pusher configuration... I've been trying to explain how inefficient moving to pusher and removing the flare on the duct actually is. Sure, pushers have an unobstructed column of air but they're receiving turbulent air to the prop itself.. The prop and motor will be impacted by this. in a standard configuration, the motor gets clean and unobstructed air.. it doesn't care what happens after it (within reason). The flare is one of the major contributors to lift/thrust for a ducted setup as well. the flare should start just above the prop which allows for the prop to achieve the same surrounding air intake that you speak of whilst avoiding losses due to tip vortices

oh, and why don't you streamline the duct struts too.

I was saying this before I like the gemfam 5 blades the shape of the blades I feel is more efficient and quieter to my ear anyway 🤷🏻‍♂️ I was running some on my rekon35 switched to the gemfan 3 bade because like you said normally more blades are less efficient but now I might go back to the 5 blade given your data because I feel the 5 blade was quieter 🍻

Youre opinion and findings about the ducts efficiency doesnt explain why the dji at 410g with ducts have 13 to 15min flight time compared to a caged 3 inch cinewhoop that weighs 410grams but doesnt get close to 10 to 15 mins. Imo opinion, youre duct design is very poor and does not compare to the design efficiency of modern cinewhoops with ducts

your duct design is flawed with it's sharp cornered and non laterally transitioned inlet not to mention the duct makes the inherent air blockage of your test stand even worse. I think you need to redesign the duct shape and use a 2-3 inch standoff behind the motor in order to get better airflow into the duct. You might even put a shroud on the stand elements in order to smooth airflow. Your effort is to be applauded but this test needs a redo.....

Chris the duct you used here are one of the worst designs, modern pusher cinewhoops have better design which makes them super efficient, one of the best example is the oddityrc25 probably the best 2.5inch frame out there