CNC 4 Carnage 4" 4mm frame with M12.
40A ESC. 4023*3 or probably 4032*3 5mm props.
Ideally under 20g.

Contenders

HGLRC 2006 2800kv. 21g
KV little low for 4S. T mount. Published idle current and ohms look good, and nice thick windings.
Conflicting data.. is it 9mm mount? is 12mm?

BH LA 2005 3450KV. 20g
KV is right for 4S. 5mm. But 1.8A idle current.. it might suck power just hovering.

Speedx2 2105.5 3400KV 21g
KV right for 4S. T mount. It was my first choice, but means cant use 4032*3 props

BH 1507 3100KV 17g
KV bit low. but its 5mm shaft, and still 12N14P. Bit small, but should be 800g. If only they had 3400KV!!

i use 1806 and would choose it again, not sure if there ia any new nice motor outthere.
if you realy force them, 15xx motors will be worse about bearing lifetime, but thats solvable.

When I started, 1806 was what you used on 250's (5")

I only have one 4", a Diatone Roma Freestyle, I built it for 4S and I fitted really cheap RacerStar budget "Racing Edition"  (Ha Ha) 2205's!

Wasn't bothered about sub 250g as had three quads for that, so its 298g without battery. I use 5" AVAN props trimmed to max length to fit clearance, about 4.2".

It's a streak..................  

I’m using BH 1507 3100kv on 4S with a 4” Ronin MK2 and XNova 1804 3500kv on 4S with a 4” Apex.
   
   The 1804 3500kv are lighter and more powerful.
   
   I fly the Carnage V2 3.5” with t/motor 1604 3800kv on 4S and they do very good.
 They might be a good 4” motor?

I have a 4” on 1408s. It’s a ripper to say the least.. I’m building a Recon 4” for a WS setup.. waiting for xnova 1804s 3500kv w/ 3mm shaft to come back in supply.. I’ve found t-‘motors but the shaft is only 2.5mm

I have a 4" Shendrones Tweaker I have been playing with for months. Tried 2306.5 2450kv motors (32g) and got 1 minute flight times. Tried 2204 2300kv motors (30g) and that was fun, close to 3 minute flight times. I would have kept those ones on longer but 2 motors threw magnets. Over it. They were old Cobras anyways.... Not worth gluing them when they were not perfectly balanced to begin with. Switched to RCInPower GTS V3 2105 2950kv motors (20g) and switched to a less aggressive prop (Gemfan Windancer 4032), and wow! Smooth as silk, less vibration, cleaner gyro noise, very, very fast, and 4+ minute flight times. Striking difference...

Edit: forgot to mention the AUW of the quad with battery and Runcam Thumb Pro is 475g.

(25-Apr-2023, 07:17 PM)EyeBotXander Wrote: I have a 4" Shendrones Tweaker I have been playing with for months. Tried 2306.5 2450kv motors (32g) and got 1 minute flight times. Tried 2204 2300kv motors (30g) and that was fun, close to 3 minute flight times. I would have kept those ones on longer but 2 motors threw magnets. Over it. They were old Cobras anyways.... Not worth gluing them when they were not perfectly balanced to begin with. Switched to RCInPower GTS V3 2105 2950kv motors (20g) and switched to a less aggressive prop (Gemfan Windancer 4032), and wow! Smooth as silk, less vibration, cleaner gyro noise, very, very fast, and 4+ minute flight times. Striking difference...

Edit: forgot to mention the AUW of the quad with battery and Runcam Thumb Pro is 475g.

For a 4”!?!? My 4” has 1408s on it.. a full size ratel, and 800mw vtx.. with a 4s 650 lipo.. it weighs 248g

(25-Apr-2023, 07:57 PM)Rob Axel Wrote: For a 4”!?!? My 4” has 1408s on it.. a full size ratel, and 800mw vtx.. with a 4s 650 lipo.. it weighs 248g

Yeah, I tried what I had laying around. Just felt like trying them before I ordered something else. The 2105's kick ass, btw.

Also, I've been flying 1300mah 4s. It's not a wimpy frame. It's kind of a basher.

475g on a 4".
Im surprised you used small 2306.5on 4", instead of 3115.

a question for more powerfull and more heavy which doesnt give a good answer for me; what rotors to use on motors above 20g?
to get response and power increasement it seems it needs fourblades, there are just some old bullnose rotors which doesnt seem to be promising to me.


what rotors do you uae on the 2205 raceratars?

(25-Apr-2023, 11:43 PM)romangpro Wrote: 475g on a 4".
Im surprised you used small 2306.5on 4", instead of 3115.

It's an old frame that was gifted to me when I started the hobby a few years ago. I should do a build log of how it came to be this today. Nothing about it feels like a brick. I did a lot to lighten it up, including switching to the RCInPower motors and replacing all the steel screws with titanium. Cam is a Caddx Ratel, and Runcam Thumb Pro, modern 30x30 stack. There is literally nothing extra on it, barely any tpu parts, it's just an old frame that can take a beating--bottom plate is a rigid single piece of 4mm bulky carbon. But it also tunes well in Betaflight and flies well, so it hasn't been retired yet. I should post a build log with some photos and flight footage. It's an interesting one. Not many people out there still flying this frame. Only thing I could want more from it is maybe 1 more minute of flight time, but I can settle for 4 minutes of hard ripping.

4min of hard ripping on 475g 4" sounds 100% impossible. But what do I know.

Anyway.. I have too many 1404, 1504.5, 1506 "toothpick" light 4" builds, and wanted something more zippy.

I talked to HGLRC, and they had 2006 3600KV but discontinued.. so only 2800KV.

Speedx 2105.5 is beefy, but T prop mount.
Maybe just wait for better option.

what rotor do you aim to use? an hq4043? a gemfan 4032?


about power, 4inch is great it provides much power on various motorsizes. maybe your goal could be achieved by battery choices more than by motorsize.

a somehow huge lipo, higher volatge to compensate: a 6s 550mah -750mah pack, would remove the feater ultralight feel either.

a 4s racer on a 1000mah pack does also feel like a featerweight toothpick compared to todays common 6s 1300mah lipos.
higher weight and higher voltage does give something close to very huge motors.


the issue on big engines or batteries, high weight, seems to be realy the rotors - none is made for the upper performance are. 4inch does lag there by set new speed records - we saw high speed values on 3inch rotors, on 5inch ... but the 4inch the size between never made some attantion by speed. i believe on 4inch would be much possible if we would have other choices on rotors.

(26-Apr-2023, 01:28 PM)romangpro Wrote: 4min of hard ripping on 475g 4" sounds 100% impossible. But what do I know.

Maybe our definition of hard ripping isn't the same.... I can maybe post a video. My flight times went up a lot after I switched to the RCInPower motors and the Windancer 4032 props.

I have a Chimera 4 on the way to me now. Found it never flown, new, unused for super cheap. It is a hard contrast to the Tweaker. Looking forward to some long flight times. I am still new to the mastery of FPV, including tuning, and custom builds. It's been a fun challenge and learning experience to make Tweaker a great flying quad. But your feedback does inform my frustrations about flight times. I see so many 5" freestyle videos ripping hard with flight times in the 4-5 minute range and I have been left wondering what is off with this one. Even with an 1800mah battery the flight time is about the same. Definitely hitting the limit of mass for the prop size.

Quote:Speedx 2105.5 is beefy, but T prop mount.
Maybe just wait for better option.

The RCInPower GTS V3 has better mount options.

(26-Apr-2023, 01:58 PM)hugnosed_bat Wrote: what rotor do you aim to use? an hq4043? a gemfan 4032?


about power, 4inch is great it provides much power on various motorsizes. maybe your goal could be achieved by battery choices more than by motorsize.

a somehow huge lipo, higher volatge to compensate: a 6s 550mah -750mah pack, would remove the feater ultralight feel either.

a 4s racer on a 1000mah pack does also feel like a featerweight toothpick compared to todays common 6s 1300mah lipos.
higher weight and higher voltage does give something close to very huge motors.


the issue on big engines or batteries, high weight, seems to be realy the rotors - none is made for the upper performance are. 4inch does lag there by set new speed records - we saw high speed values on 3inch rotors, on 5inch ... but the 4inch the size between never made some attantion by speed. i believe on 4inch would be much possible if we would have other choices on rotors.

What motor and build would you use for a Gemfan 4052 flash prop?