Generally the more blades you have the less efficient it is as each blade has drag.
Just using optical flow is a good idea, I dont need a rangefinder for flow hold
In firmware 4.0.x, I experienced drone continue climbing when optical flow enable WITHOUT rangefinder in 1, I accidentally place another external rangefinder height sensor in 2. I didn’t configure the HEREFLOW onboard rangefinder to 1.
I am not sure does this still happen in latest firmware.
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Your flight times both indoors and out are very impressive given the size of the quad. I’m looking forward to your iteration on this project!
Coincidentally I’d recently bought the same motors off of Aliexpress to attempt the same exercise 
I haven’t gotten far with it but plan on using 6mm CF arms and 3D printed mounts for the motors:
The mount needs some tweaks but I’d be happy to post the STL once I clean it up. I got some of these screws to use 3mm M2 Screws but I discovered I don’t actually have an Allen wrench that small 
I also characterized one of the motors on my makeshift thrust stand: Aliexpress Folding Prop 2750KV Thrust Stand Results
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Those mounts look really nice with the wires going through the arm. How much do they weigh?
One motor mount weighs 1.0g. I think I had infill set at 40%.
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While looking for small compatible boards I have seen there was this AIO board, I didn’t think there was another micro AIO board supported by Ardupilot and that this one had changed the gyro, but the supported version is still available in places, unfortunately it’s expensive but it’s the only one I could find with an analogue OSD.
I keep looking at that HD zero camera, if I can hit over an hour with the analogue camera then il get it to try and make a digital version
I made a 3d centre to glue in rather than carbon plate, I can get it down to just over 1g with the fc mount integrated.
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I have found some ultra light 6mm carbon tube, I think I might be able to get the frame weight under 10g.
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I have found some 6000mah 21700 cells. They are around 3g heavier but it’s 20% improvement in capacity.
https://www.reddit.com/r/flashlight/comments/17hseid/vapcell_f60_217006000mah125a/
https://www.aliexpress.com/item/1005006117697035.html
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What does 21700 means, model, some capability?
What battery type is it?
Does it has the surge or peak capability as well?
Does this type of battery and series it work also, we were discussing it previously. This type too.
“21700” is a specific battery formfactor, similar to “AA”, “Baby”, “Mono”, etc.
21700 is a round lithium cell with 21mm diameter and 70mm length.
Basically the bigger brother of the 18650 lithium cell.
1.5V cells maybe work, I’m not sure if they can provide the needed current and you need more of them in series for the same voltage.
The exact cell you linked however is likely a scam, there’s no way in heaven or hell that they crammed 12.8Ah in there. And even if that technology existed today it would cost more than 4$/cell.
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I bought it for my home digital lock, I date stamp it to see how long it lasts. we will find it out. unless we have an E-Load (electronic load) machine/equipment to verify it.
those batteries are generally around 800mah, they are for xbox controllers and other low power devices not powering a drone. You would need 22 of them to equal the capacity of a single 6000mah 21700 cell.~
you can find the specs fo the cell here
I have ordered some BetaFPV BT2.0 connectors, they are about 1g lighter than XT30
Here you can find my old sub 250 arducopter (still flies well) with analog FPV and optical flow 2s 18650 20 minute flight time. If it helps the hakrc escs can be modified to work on 2s. But do cell phone batteries have a sufficient discharge current like 21700?
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Well, I thought they would but so far the phone batteries I have tested haven’t really been great. One was a cheap replacement for a Samsung and one was a genuine battery for some other brand. Both 5000mah cells got less than 4000mah when using 5A, so smaller cells running 3 or 4s might be better, but these don’t seem to have the output for 2s. im not sure if its just the quality of the cells im using or its what I would generally be looking at with mobile batteries but I’m not spending more to test since the 21700 at 6000mah is looking much better.
my v2 build is currently adding up to around 205G with 6000mah 2s.
Someone else has informed me of that modification, Im going to try it on 3s to see how long it can fly for before I modify it, unfortunately it’s been raining since my last flight.
The problem is the weight of the 21700 with FPV, GPS, Compass, Optical Flow (a quad Arducopter without GPS Compass would make no sense in my opinion). But with a dedicated frame and other measures you could manage to make your quad fit around 110g (without battery).
at 3s no changes are needed (esc works well and discharges at 2.5V anyway). With modified esc I used 18650 at the limit of 2.5V li ion chemistry. The entire quad was flying on 5V power
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So far going with the listed weight of all the parts plus a few grams for 3d printed parts it should be around 65g without a battery, including a gps/compass and fpv.
frame 8g, motors + props 40g, GPS 2.6g, camera + VTX 2.8g, flight controller+esc+rx 3.6g, and a 6000 2s battery at 144g, battery connector 1g, motor bolts 1g,
its basically a 6 inch tiny woop with a giant battery.
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You could shorten the leads to the ESC and the battery lead itself to save a few more grams if needed? I can’t tell from the picture if the connectors are XT60 or XT30…if XT60, you could probably drop down to XT30 as well to save another gram.
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Its currently running XT30 connectors but I have ordered some BT2.0 connectors that are a little lighter. Im only going to be using about 8 amps at most so the BT2.0 should be enough.
I believe the f405 classic version of this will work with Ardupulot, it’s probably a better board for larger motors with its 12A escs. If it had an analogue OSD I would have got it.
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I built a prototype carbon frame using the “heavy” 6mm tube and 0.5mm carbon i cut with some scissors (using a broken hand), Its not for flight, I just wanted to see if the araldite was going to stick and what it would weigh. Unfortunately, it must have got disturbed, so the carbon plates have moved.
This frame weighed 13.9g and was very rigid. I had to put a lot of force into it before I heard any noises from the carbon breaking.
Next version I will turn the centre around, I was trying to line the motor mounts up with the grid and got carried away and ended up with the centre in the same orientation.
The motors mounts are far narrower than I thought, so instead of the large square motor mounts its going to be a much smaller T shape piece of carbon.
The mavic mini 3 pro motors arrived and they are very light, only 7g without the propellers and around 8.9g with them.
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