Designing a quad setup – Scaling down by the numbers20:22

Great video. We need an equation to help determine quad preference

You almost had it sounding like you knew what you were talking about ! ?

Oh man, this technique makes designing and error-checking a quad on paper (in excel :P) so easy! 🙂 Also – if I have a very light setup (lots of headroom under target weight) what would happen if I put in a bigger battery? I’d voilate the 55% rule, but still have T/W ratio and disk loading metrics in the green.

Guys, AWESOME 66gr. 2.5″ build with 97gr. AUW. Thanks for the info Kabab, which led to keeping it 2s and high KV to get both performance and low weight:
Kingkong 1105 8500kv (5gr each), gemfan 2540, KT100 frame with nylon standoffs (super low drag and 11gr. lighter using nylon), 600tvl banggood cam with mic (good color and light change speed), atx3 vtx (25 to 200 mw), 80db beeper with led, lightest 20mm FC with OSD and 20mm 4 in 1 you can find, 2s 450mah (31gr). Simply spectacular handling and power.

HI kabab, I love this theory brainfarts. I have this on my electric ducted fan jet projects as well where my rule of thumb for efficiency is Watt/kmh needed. Basically this formula is bs because of the units used (N*m/s)/(m/s) but it gives me a good comparison of high speed edf projects on forums. I am in need for 650W for 300kmh where others need 3-3.5kW for the same top end speed. My ratio includes frame design, drag, drive line efficiency, dimensions etc and I never could understand why many need gobs of power to pass even a 200mph barrier which is still hard to achieve in edf jets due to lack of efficiency of small rotorblades . Main reason for this is many use multi blade slim rotors which suffer prop wash a lot thus terrible efficiency at high speeds. I use 3, wide blade rotors to cancel out prop wash due to higher pitch thus I can use smaller thrust tube diamaters up to 65% where others need 80%max before blade stall occurs.
It’s great to see mind like theories and I am keen to extend this way of reverse engeneering in drones as well. Props have more efficiency when diameters are larger, 2 blades have less prop wash as 3-4-6 blades. for this reason smaller motors have 2 blades. The tiny whoop has ducted blades but because of the small diameter more blades are added for sufficient blade area.

Have a browse on super light 5″ builds. On rc-groups there are only a few threads where RTF weight is about 270gr. They prefer 2 blades and they do respond pretty impressive at throttle response. For small race tracks it is a very interesting nice market.

The Druckbär Ultralight 2 is a great example. On their website you can even see their parts list for suggested hardware. It would be nice to see more info on superlight builds.

kind regards,
Erik

This is amazing. I spent last 2 months trying different motors, props, batteries and gopro to get my 4s session 5inch and 5s hero6 6inch to fly similar and just got it last week.  And I was more than thrilled when I calculated this….

So i want to build a value light weight quad and i am having trouble picking up some decent budget light weight motors. I have decided to buy the 2205 motors from BH but i want to know which one to buy. First there is the R4 BH 2205 2450kv and then the R2 2205 2600. Will they have same performance. The R4 is obviously an updated design.But R2 are alot cheaper but the problem is they are not available in baseless design from where i am buying. Let me know what you think. The R2 2205 2600kv (14.99) or the R4 2205 2450kv (17.99). And also what are the true kv of both the 2450 and the 2600. Is it the same.

I have a question regarding the Lumenier Asgard AIO Flight Controller Do you know how to get the smart audio working for a TBS unify I’ve been racking my brain and researching stuff and have not been able to get it to work I would really appreciate it if you could help me out.And I love your channel and all the things you’ve been doing they are really amazing thanks and keep up the good

hey Kebab great work there.
I wonder what 1107 Motor you have chosen.
Atm I can only find 1107 that provide about 175g/motor on 3s 2.5 ” and you get about 350g/motor

When I go back and reflect on my different builds… i think this makes sense. Thank you for making numerical sense out of this.