Perfecting the Best Sub 250g FPV Drone. Fixing flaws and increasing reliability and performance.
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- Опубликовано: 8 июн 2022
- This is part 2 of my ideal sub 250g DJI HD design and build series, where I take the best tested motor and propeller combination and use them to build a lightweight drone with a thrust to weight ratio as high as possible, without sacrificing durability, reliability, and essential features. This video I work towards fixing identified flaws in the frame design from part 1.
Part 1 (includes a lot of additional information relevant to the build in this video): • Best DJI HD Sub 250g F...
Build Information
Scythe/Reaver frames:
Scythe: www.cncdrones.com/scythe.html
Reaver: www.cncdrones.com/reaver.html
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Scythe Carbon Replacement/Spare Parts + Walksnail (25-26.5mm mount top plate): www.cncdrones.com/scythe-repl...
Reaver Replacement/Spare Carbon Parts: www.cncdrones.com/reaver-repl...
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Other Build Components:
Motors: T-Motor F1404 3800kv - www.banggood.com/custlink/3Kv...
Propellers: HQProp T3.5x2x3-PC
Video/Receiver: Caddx Vista Nebula Nano Pro - www.banggood.com/custlink/K3v...
Flight Controller/ESC: Jhemcu GHF420AIO - www.banggood.com/custlink/KmD...
Battery: Tattu R-Line 550/650mAh - www.banggood.com/custlink/KDD...
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Relevant Test Videos:
3" vs 3.5" on 1404 (Incl 3.5" comparative propeller tests): • 3.5" vs 3" Propeller P...
3" vs 3.5" on 1404 (Incl 3.5" comparative propeller tests) Part 2: • 3" vs 3.5" Propeller T...
1404 vs 1408 on 3.5": • 1404 vs 1408 on 3.5" P...
1404 comparative motor testing: • Recursion Labs - 1404 ...
Previous 3.5" build video: • Best DJI HD Sub 250g F...
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Build Propulsion Reference Data Charts:
Thrust to Motor Utilization: i.imgur.com/pu2KzNG.png
Efficiency by Motor Utilization: i.imgur.com/FPHusm8.png
Thrust to Watts: i.imgur.com/3RQSiGo.png
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Contact: expfist@recursion.tk 
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Unfortunately I find CNC Drones really expensive, especially for small frames like yours. Maybe you could push it to some aliexpress distributors? :)
That is awesome. You have cracked the code with this one.
Just got the frame stoked can't wait to try it
I’m blown away by the weight of this build…as I said before my 3.5” is coming in at 179auw I’m super interested in this build. My build isn’t much different than yours either
Looks really fun, impressive how light you got it. 150g seems like the lower bound for DJI without having the FPV system take up too much of the AUW. I'm not really a fan of unibody frames or bottom mount batteries but I guess that's part of why it's so light.
Yeah making replaceable arms would increase the weight significantly, and having it lighter helps reduce the chance of it breaking, but nothing is indestructible. One of the reasons I have the vista stack on the top is so that swapping out the bottom plate would be much easier.
It was a worthwhile trade-off for me personally since I'd rather have the possibility of having to spend 10-15 minutes to replace the bottom plate to get the reduced weight and increased performance/agility all the time.
Best video yet! Love it man beautiful build and nice thinking. If you wanted to save a touch space and weight you could mount the vista on the stack using little spacers. Been single stacking for a couple years with no problems ;)
I used to build all my 3" that way, but it's a huge pain in the ass to get at the flight controller or swap a base plate since you have to take the Vista apart/off first. Worth the extra gram for sure.
Your work on microquads is amazing and strangly not as popular as it should be.
I've decided to do this drone as my first full build. I've done modifications to my others but never a full build and i'm looking for exactly a freestyle ripper under 250 grams that could fly a gopro. You're really nailing the one-size-fits all and I'm excited for the parts to arrive.
That's awesome! I look forward to seeing it in action.
The DJI mini 3 pro has 6 inch propellors and has amazing flight time. I'm wondering if we can do that with an fpv quad, sub250g, 6inch and dji o3.
Hey, I was just wondering if it would be better in terms of speed and efficency if I change my sub 250gr setup from 4 inch biblade to 3.5 inch 3 blade setup
The drone I am using is a 4 inch bi blade drone with naked gopro as my speed and freestyle work horse when sub250gr is a requirement.
it has;
1404 3800kv motors
Gemfan 2 blade props
weights 244gr with naked vista, naked gopro and Tattu4s 750mah battery.
i did build one my self and i would love to see the pid tune and filer settings on this one.
Bro can you please modify the scythe design to be able to mount 12mm motor mounting option? I have axis flying 1505 motors. They are great for 3.5 inch props.
really liking how this quad flies. Would there be space for a express lrs receiver? (i would build it with analog vtx)
I 'm running a vista & run cam HD! 1507 motors, 3.5 props. w/ 4s battery! Sub 250!
Hey, nice job! Could I fit dji O3 camera in the reaver? I know you have the helios build but I want to have the dji + naked go pro on top.
very nice!!! where were those cool aquaducts? streetsville? theres some cool ones near millcreek and erin mills parkway that could be fun you you
Hey I just saw your frame on cnc drone and no wonder I believed you where playing planetside haha
Comparing it to a 3” 1s build, do 4” props give this more efficiency and higher disk loading ratio? I saw you tested 4” props on 1404 but what is your ultimate reasons for going with 3.5 vs 4 inch props?
Hi there, the video is quite some months old but maybe you still see it. First, thanks for the video and design! Very informative! I just wanted to buy a frame but being located in Germany, shipping from Canada is a bit pricey. Is there any other shop you collaborate with and has the frame available for purchase?
I would DEFINITELY BUY ONE MAN!!!! I am a sub 250 quad guy and this is sweet👍🏽 the places I fly have gapers so just in case I get bothered I can say F off it's under 250 😁 of course I would buy one prebuilt if possible 😏 ✌🏽
1:48 Blaze it... I want to build THIS, but adapted for Dual 21700 batteries... Will need to learn how to calculate how much bigger props, motors and so on I'll need... Should be 4"? Batteries are 140g, all up then
Would it be possible to get a sub 250g dji hd fpv quad to fly for 20min+, as a cruiser.
Alright, ya got me. I just ordered a Scythe with the Vanguard base plate. I **love** my Crux35, but the base plate isn't the strongest. I misjudged a park bench the other day and delaminated one of the front arms. At least I had a spare already on hand, but I definitely want something stronger. I already ordered a set of the 3800kv T-motors and the updated HQ 3.5" props. I've also been using the 70g RDQ 4S 850mah packs. Can't wait to get it all together. I've got the 1S Lite Walksnail kit, this thing is going to be super light and powerful.
Nice. Show me when you're done. You should really consider some 550mah tattu packs. 850mah is overkill.
@@RecursionLabs Will do! The motors and props showed up today, the frame is already in the US but still has most of a continent to cover. I didn't realize the motors didn't have plugs, so I'm going to wait to install those until the frame shows up and get it all done at once. Current dry weight is 91.3g, AUW is 161.5g. I'm interested to see what it's going to be with all the new goodies. The RDQ 550mah packs should shave off another 14-15g.
@@RecursionLabs Got the frame and it looks and feels really good! The original Crux frame feels downright fragile by comparison. For several reasons it's turning into a more challenging build than I expected, but I think the end result is going to be massively worth it.
@@RecursionLabs Alright, I got it put together about as good as I'm going to get it for now. Found some TPU camera plates my friend had printed up for me and trimmed them to fit the Scythe. Got most of the other issues solved up and did a test hover and video check. Dry weight is 99.8g, AUW is 158.7g. Is the email address listed on your youtube account the best place to send pictures?
I like the scythe now it adds support for 25.5x25.5 AIO. But please also add support for a micro size walksnail camera.
Great progress 👏
I've moved on to more powerful, just a little over 250g, 3.5 inch builds.
Thing I've realized that if it's not loud, people dont care either. Reason for me to go low weight was to reduce noise. Of course its all down to power to weight.
Best props for low noise are HQ T75MMx5 or 85mmx6.
You have to upscale the motors to 1804 or 2004/5 though.
6S is great too. Like the tattu 5506S.
You can get more power with 1408 motors (as per the testing/video I did), but then you'd need a bigger battery to drive it, so it becomes heavier for sure. I'm tempted to build one with them at some point just to try it, but it's not like I'm hitting full throttle when flying this.
@@RecursionLabs 1408 and 2004 are same stator volume.
Lets assume 14 vs 16g approx. But on 2004 you have better throttle control and cooling.
Also the Pro's here on youtube recommend 2004 over 1408 with cinewhoop props. I COULD test myself, but they already did and save me time and money
@@chrisbee5481 I've yet to test cinewhoop props even though I have them to get to eventually (and even made ducts for my stand). 1408 area really good for 3.5" though. I have 2004 motors for testing though so I'll be eventually publishing comparative analysis on them. I've just slowed down a bit with building and it being the best time to just get out and fly (spring).
@@RecursionLabs use the HQ cinewhoop props without ducts! They are so quiet. Also very grippy and lots of thrust. Use your 1408 motor on the HQ T75MMx5 on a flight. You will love it
Nice frame! Do you think you can share the DXF on your thingiverse page?
I'd like to try to cut it myself.
Looks like it's close to the perfect legal race practice quad.
Have any of the "fast guys" you race with tried it out?
Super cool, I aim for this category too and I am saving money to build one.
I am a little scared of the naked vista, but I am sure it will be fine.
The only problem with a naked vista is if you keep it on the ground too long. I've never killed one from heat though, but if you crash and don't find it fast enough it'll shut down (which can be a problem if you're using the DJI controller). I did thermal testing on them with a thermal camera a while back before committing to using them, and it only takes a small amount of airflow to keep it happy.
@@RecursionLabs nice! Thank you for the answer.
I know is not your goal, but can i ask you if you will do a flight time test (like how long can it cruise)
@@damianomotta1809 That was a consideration with efficiency for sure. Check the last video linked in the description. I tested 3 different batteries to show the flight times (should be a bit better now). As mentioned, I have some ideas on how I could have it turn into a long range build with different batteries (and maybe propellers), but that needs some experimenting/testing.
@@RecursionLabs 👍👍👍 thank you
Do you share your CLI file for settings and tune?
Finally! Nice setup
I go for 4600kv on 4s 3.5 Zoll. Weight without lipo 115gramm. I can compete with 5 inch racers on race tracks. Also on larger tracks not only on tight ones
Well at least you have some ideas how on how you could potentially save some weight. Really fun to fly, right?
@@RecursionLabs yes so much fun. Love your testing
Betaflight preset possible? I really wanna your setup.
Will this fit the DJI O3? Cheers
Whats the pids look like on this?
Wow! This is super interesting! I'm interested in building one but with HDZero instead. Would the top plate be big enough to protect the Race 2 VTX? It's 34mm x 34mm, M3 20x20 mount. If it doesn't possible to have a top plate that does?
Did I see that right that this only uses a 2S battery?!
Have you compared a 1404 to a 1505?
It's 4s
Any thoughts on the FPVCycle 16mm? They fly amazingly well on AOS 3.5. I run them with r-line 750mAh and I'm around 249g. I'm really tempted to build one like yours though, I love lightweight!
I have not tested them, so I can't really comment about performance. They are 16g, so not exactly light weight motors.
I built the Scythe. I like it very much. It flies well, but I have a problem with roll axis noise, I can't get rid of it and I can't tune the Scythe as I would like. Other axes, pitch and yaw are absolutely quiet. How is your Scythe, are all axes noise free? Would that help me, I may have a faulty gyro. More on the intofpv site, mini quads and 3.5" Scythe HD thread. Thanks for the help. Momo
I found your thread and have replied to it. Glad you reached out.
I never realized you were Canadian! Greetings from a fellow Ontarian 😁
Such an interesting video, all the way through. The frames turned out great and the builds look like they fly amazingly even with the naked gopro.
Being true-x frames, how low of an angle do you think you could run with the naked gopro without getting props in view? And other than for weight savings why did you decide to go unibody?
Greetings! Not sure on the angle. I think 35 degrees should be fine though since I was running that originally. Weight savings is the reason for sure. Every 3" I've built (since 2018) has been unibody. This one is the easiest I've had to swap since the vtx is top mounted along with the AIO board. Bit more effort than changing an arm, but it's more than worth it to me for the weight savings.
Thank you for this frame. Sadly it has to be imported expensive but it is worth it. Did my First run in my garden. Video on my channel. Could you share your pid tune?
For long range, you could maybe use a 3s 18650 pack
You read my mind! I want to bench test the motor/props on 3s first to make sure it has enough thrust and is more efficient. I also want to make sure the vista will work at the lower end of the voltage.
What P:I:D balance ratios did you end up at when tuning on 4.3? I'm looking for a starting point for PI:D and P:D balance, there's not much info on tuning ultralight 3.5s
The ratios are close to stock. I have I and the master multiplier bumped up slightly. The real tuning came from tweaking other betaflight settings, like filtering, and giving it more low throttle authority with Thrust Linearization.
@@RecursionLabs Got my Scythe and I've been dry fitting and prepping my build, sadly realized my 1404.5s from Pyrodrone are 12mm mounting as opposed to the required 9mm on the Scythe frame, so I've gotta order some more motors. Looks like the tmotors you used are a good option. I have a question about screw lightening and the naked vista, I'm gonna try using polycarbonate stack screws and am considering reny/pc prop screws with titanium motor base screws. Have you experimented with lightening prop screws? I feel like the reduction in rotating mass could make a big difference, I wonder if metal screws are necessary for the props in particular. I definitely think metal will be necessary for the motor screws though. And about the naked vista, what size spacers did you need for it? Do you think polycarbonate screws also holding it together are a good idea? I've got a bunch of pc screws and can cut em down to any length
@@RecursionLabs One more question, do you think 4600kv on 4s is too much? I was gonna run around 3800kv but since I'm buying new motors I'm considering going all out with the higher kv, I don't have experience on 3.5" so I'm not sure if 4000+ would be overkill and cause tuning difficulties or reduced throttle resolution.
@@avgvstvs96 All my builds have m2x7mm titanium screws now for the props. 7mm seems perfect. I put spacers on thingiverse for the Vista stack that I designed to be the perfect height, and tight enough to become threaded when put on. I printed a batch of them at 1.4mm layer height so I have enough for many builds.
@@avgvstvs96 I did test a 4600kv version (I don't think I published it) and it lost a lot of efficiency, so it wasn't worth it. 3800 is perfect for 3.5" on 4s. 4600 is probably good if you want to run 3s.
Good build. In the first vid you said you would test 4 and 5" props I would be interested to see that testing to see how they stack up. 4 or 5" low pitch bi blades work surprising well on 1404 with a sub 100g build.
That's still coming. I've basically completed all the testing and wanted to get this done/out so I could compare thrust/weight between sizes using this as a point for comparison. I've also just had so much fun flying 3.5" that I wanted to focus on pushing it further before seeing if bigger makes sense.
Edit: I did publish testing with 4" on 1404 3800kv already if you missed that.
@@RecursionLabs Ah that's awesome I look forward to the next episode👍🏻. Did you pre-order a Walksnail? I hear DJI might have FPV2 coming out this year so I held back.
@@changeagent228 No I think preordering it would be a bad idea. No idea how well it works, and the only available goggle is 90hz. I ordered more Vistas after it was announced. Maybe in a year it will be worth looking at. I'm very happy with the DJI system outside of not having full canvas mode.
@@RecursionLabs Same here rocking my v1's still working like a champ. Going less than 120hz no no. The Margerine hack has allowed full MSP displayport support and live audio. This month the gui version should be ready for release. This is massive for v1 and v2 owners. Even the 13.3KM limit is being worked on 😄
@@changeagent228 I mirror your thoughts. I'm hopeful for the work Joonas and co. are doing as well.
Hello, can I buy a dxf of this frame?
I can't order from cnc madness :(
Why not?
@@Wild_FPV No one does shipping to Russia this days
@@LeshaRodin Oh that's too bad...
Let's see if Recursion would be willing to sell you the dxf
+1 to the question 😄
With the Crux35 along with a Runcam Thumb Pro, GPS and Beeper, I'm still well under 250g. Therefore, I think you need 4 inches to exhaust the 250 g. That's exactly what I want, only it is apparently so that there are really hardly Quads and frames for 4 inches. Too bad because the best sub250 drone has a weight of 249 g.
Being heavier doesn't make it better, since you'll need more thrust to achieve or exceed the thrust to weight ratio, and have more interia. If you look at more recent videos where I test 4" and 5" motors/propellers you can see some good data on that.
@@RecursionLabs Thank you very much for your youtube. There are not a lot of FPV LAB videos out there...
Pls add 25mm FC mounting options? 20mm AIOs are less reliable and way harder to find, and I have 7 25mm aios sitting around right now!
i think its the perfect frame for me otherwise, that 25mm mounting without needing an adapter is crucial for me! i otherwise have every single other part i need for this build and really want it if you can add 25mm electronics
I agree that they've been much harder to find lately. I already have one designed and cut that I need to quickly verify.
@@RecursionLabs please update me when 25mm fc mounting becomes available on cncdrones!
@@RecursionLabs how much of a compromise do you think it would be to run a normal vista with heatsinks on the reaver? i don't really want to risk overheating my vista by stripping it. Also, have you tested the resonance performance of this frame? How do the blackbox logs look?
@@avgvstvs96 Every gram on a small quad is like 4 grams on a larger quad. It does make a noticeable difference in weight. I'm not saying it's not possible, but I've yet to have a Naked Vista die from overheating. I have 3 Scythes, 1 Reaver, 2 x 5", and have had older quads with them without issue. They do overheat without airflow and turn off, but the Scythe is designed to go from an 'overheating' state to cooled in a few seconds since the P1 chip is at the top where there is a ton of airflow during flight.
Unless you have a regular Nebula Pro instead of the Nano, I'd suggest going with the Scythe and a Naked Vista. If you want the 25.5 base plate you'll have to since the one I'm testing is for the Scythe only.
i really want this frame but i have a diatone mini stack so im almost positive the vista wouldn’t fit?! i trust you and your frames and i want it SOOOO BAD. its been on my google bookmarks just staring at me”BEST NEW DRONE FRAME”
If it's the Scythe, then it wouldn't be practical for that stack, no. You also wouldn't want the weight of the extra board/hardware. I've run a 20x20 AIO on a 5" racer, so a stack isn't needed anymore on 3.5".
@@RecursionLabs i get have seen your videos for awhile and you like the jhemcu boards, but the last 3 i received were DOA, I bought a mamba stack because i heard they’re the best and now i haven’t had an issues but the extra weight bothers me a lot too, what aio product have you had great luck with? thank you good knowledgeable sir
@@RecursionLabs i’ve been so heavily influenced by your tests and i have almost the same build with the exact same motors. i REALLY want to try your frame man i love people that are passionate and use actual scientific data
@@brokeboi369Which JHEMCU board did you get, and why what were the issues with them?
@@RecursionLabs JHEMCU GHF405 PRO Bluejay 40A 3-6S AIO Whoop Flight Controller, i got this 3 times, the first one was good lasted me until the usb port ripped off and ftdi adapter wouldn’t work to connect to betaflight, second on i received didn’t connect to betaflight period right out the box, 3rd one i received doa one of the esc had a problem and would reach max rpm at 25% throttle, making it so terrible to fly(i flew for seconds and realized something was wrong) changed motors and esc problem still persisted, now im quite literally scared of AIO boards because if one things wrong its all wrong. i’m sure you could change my mind
Do not buy the new updated JHEMCU GHF420AIO-ICM flight controller! Use the new 25mm base-plate option if you can not find an alternative 20x20 board. See this video for more details: ruclips.net/video/5C3RGUSsdLM/видео.html
Great build......but this just shows the extent people have to go to comply with stupid outdated legislation that makes no fking sense.
Trying to get into FPV, but this remote ID privacy and safety concerns, plus the increased cost to the hobby since 2020/21, is kinda making it hard.
Truth is I'd be flying this if it wasn't for regulations. Components are significantly smaller than when we moved down to 5" from 10". It just makes sense now.
LMFAO... my 3" @ 244g crushes this.