how much difference is there (when we talk about lightweight 5" with 1407) motors between 4s on 2800kv and 3s on 3600kv motors

The lower voltage would definetely give less torque which if you're looking for using the 1407s on a 5" you will need.

Since building the 1407 build I decided to let my backup lightweigh RFX185 go if anyone is interested:
https://www.rcgroups.com/forums/show...RFX185-5-build

My new build will be like this. Looking foreward to get the frame and try if its working

Hyperlite Floss V2
Tmotor F30
Hobbywing FC with 4in1 combo (40amp)
TBS unify
3s 1050 tattu 75C
props, I will try dualblade cyclone, and HQ 5x4x3
Full titanium screws
micro swift camera

If this isn't working than I will mount my beloved Luminier 2206-2350 and fly again with 4s 1300 EPS lipo (150gr)

SuperBfight

I'm very happy how it turned out.... had to re-engineer the camera bracket but it worked out more perfect than I could of hoped for! Here's the Build....

Bfight frame with re-engineered camera bracket
Runcam Micro with M2x10mm screws and nylon washers and nylon 3mm nut as spacers..... very secure
F4 AIO 30amp Includes VTX200mw and even the buzzer!
GTS2305-2700kv motors (Awesome Motors!)
Dal 5050-2
Camera Angle: 72 degree's
5s-Capable!
Total Cost: $180

Nice build! That thing is going to be crazy fast.

Originally Posted by DMCfirestar500

Well got to say I'm very pleasantly surprised with the floss on 1407s. Here is the initial build:
Floss v1
BH 1407 3600kv
Flip32 F3 asgard 30a all in one (ESC/PDB/FC/OSD)
Runcam micro swift
Eachine micro vtx
Battery: Venom 4s 1000mah 50c
Props: 5045 biblade pictured but after tuning pids through on some gemfan 5152 bi-blade (both props fly similar).

It is lighter than I thought it would be and flys nicely. It seems to float more than the RFX185 but that could just be the lower torque and how I was flying today.

I'll try and get some dvr footage this weekend if weather cooperates.

Oh man it looks so nice !!! Looking forward to seeing your DVR !!! -- I just found this frame which looks crazy light too: Druckbär Ultralight 2

Here is my 230g Floss 2 build with 2205 2450kV motors. All components and build log are here: http://multigpracing.quadifyrc.com/

So long as the weather holds out I'll be having my first race with it this weekend.

I ended up with a weird hodgepodge of components for my first ultralight.

Floss 2.1 Prototype (will modify mount holes)
HGLRC 1407 3600kv
Diatone and KingKong 5040 bi-blades
HGLRC XJB F428 triple stack
Micro Sparrow
AX II u.Fl
Spektrum 4648
CNHL 3S 1000mah 70C XT60

Weight on paper is 153/267g dry/AUW. I would guess another 25g for the actual build. Still waiting for parts on the slow boat.

From my best guess, 3600kv on 3S is the same theoretical RPM as 2700kv on 4S. Only one way to find out how it actually flies...

I'm getting 2 minutes with 450mah 4S packs on this little nugget, the 4" V1S props are amazing. There's a bit more voltage sag on the tiny pack, but the float is insane. I kinda have to force myself to bottom out throttle on this thing.
AUW of 197g with the small packs.

Im following the long 250g 5" build thread.
After a week of research - not impossible, but very impractical.


Long range light 5".
FC 20mm 4g
4in1 ESC 5g (20A)
Cam w/vtx 5g
Rx. 2g
5030 Props. 10g
850mah 4s 75C 107g - 3 min fly time??
( Smaller is very impractical for high amps)
Total so far: 133g.. looking good?
These are mostly FIXED regardless of size or performance.

117g left for frame and motors.
Most 5" frame us 100g+.
Lightest practical 5" frame is 55g.
https://www.google.ca/amp/s/www.ifli...product_id=496

62g left for motors. 4x 15g 1407? 1507? Barely made it!!

https://www.dropbox.com/s/ka0jj75b3n...00KV.xlsx?dl=0

Whats wrong?
≠============≠
1. What about antennas? Prop bolts? Battery strap? +10g
2. Even honest not underrated new 4s 75C 850mah will struggle pushing 16A/ motor. Enough for only 500g thrust.
A 190g 1500mah 95C gets you to ~25-35A/motor. Enough for 1000g+ thrust.
3. 10g for better 30-35A 4in1 esc.
4. Surely whole point was long range? R9 Slim 4g.
5. Just crappy 600TVL? Hawkeye 4K split 20g.
6. Finally, 1407/1507 struggle on 5".. accidentally put 5045 and they are toast. Upgrade to Hyperlite 2204. 20g each

Upgrade weight:
130g

Total:
380g

Advantages:
≠≠========≠≠
You can fly fast (1300g thrust/ motor).
You can fly far (double battery).. better rx/vtx/antennas.
Record 4K.
Can use high >5040 pitch props for acro.
Higher usable thrust/weight.

Conclusion.
250g just for sake of hitting arbitrary number is stupid

https://www.myfpvstore.com/shop/quad...ick-your-size/

250g is too easy.
Lots of guys already using the 1407/1506 4s 5inch combo.

But, can we go further.. sub 11g motor??1404 or 1206 maybe?

Try some frames from www.can-am-rotors.com

This thread is so old but yes it’s much easier now to to ultralight 5” 250g all up than it was almost 3 years ago when I started. I still fly a 1507 5” that is 160g dry as my yard flyer. Keeping such a light weight adds substantial durability and runs so much more efficient.

I'm also revisiting my 5" build now that we have a 20a aio whoop board. Dave_C with his frame design for that board.

5" Toothpick (Not kidding!) (11 min 25 sec)