I am aiming for a quad under 250gm AUW with gps and fly using 2 x 18650 li-ion.
I have to restrict to 2s due to weight. Many people told emax 1106 4500kv would give more flight time.

Parts used,

130mm dead cat style frame, it can take 20x20 or 30x30 stacks and can take 11XX or 13XX style motors.
EMAX RS1106 II 4500KV motors
Gemfan 3025 2 blade props
Hackrc 15A 4 in 1 ESC.
Matek F722 SE FC
BN-880 GPS/Compass
Eachine TX806 VTX
FrSky R-XSR Rx
No Camera yet.
2 x Sony VTC6 3000mah 18650 Li-ion. These can discharge up to 20A. I think my current requirements would be around 10A

I know the FC is heavy, but I needed one with baro and F7. There wasn't many choice available in 20x20.
VTX too is heavy, soon will be replacing it with light weight 20x20 stackable type.


Dry weight came to 128gm and battery weighs around 103gm.
Yet to do a hover test.

This is a very cool build! Thanks for sharing with us.  Looking forward to some in-flight videos.  

I did an indoor hover test.
Hover throttle percentage starts from 70% and I got around 13min flight time. In the end I did not have any more movement available for throttle.
But there was still juice in the battery. It was 6.8V (while quad on air). I know I could reduce it down to 6.2V at least.

Is there any adjustment I can do in INAV or x9 lite to adjust throttle, so that my hover throttle percentage come down? So I have more throttle stick deflection available?

# get min_check
min_check = 1020
Allowed range: 1000 - 2000

# get max_throttle
max_throttle = 1980
Allowed range: 1000 - 2000

As your voltage drops, so will your rpm's. I'm curious if you might want to go to a higher KV motor instead, then do a throttle limit.

(11-Jan-2020, 05:23 PM)sloscotty Wrote: As your voltage drops, so will your rpm's.  I'm curious if you might want to go to a higher KV motor instead, then do a throttle limit.

I had initially tried with 1104 7000kv motor. Flight time was around 10min. But hover throttle was between 60% and 70%.
What is throttle limit? And how is it done in INAV?

You may not need a throttle limit if you go to say 6000kv of the same motor.  Bardwell has a video on throttle limit in BetaFlight.  Not sure about iNav.  I just know that the 4500kv is really made for 3-4s.  The 6000kv is for 2-3s.  EngineerX on youtube doesn't provide thrust data on 2s on the Emax RS4500. With the 6000kv on 2s with 3020 2-blade he gets 215gr thrust at 9.5a.  (Older version of that motor though). Don't know how that would compare with the 4500kv.

I believe adjusting your endpoints and throttle curve will allow you to alter that value.

https://oscarliang.com/adjust-tx-channel-mid-end-point/
https://oscarliang.com/throttle-curve/

1+ throttle curve solve the throttle resolution on a 1s build with low power to weight ratio for me.

high kv would solve the issue, 4500kv on 2s would have max rpm of 37800 in theory - at 8,4v. on 6v there would be 27000rpm in theory. not much on 3“.
i beleive a reason about performance and efficiency would be a 4“ blade. as the motor can handle 4s on 3inch, this should work well on 2s with a light 4inch blade. 15a esc should be fine aswell.
https://m.banggood.com/2-Pairs-HQProp-T4...90493.html

lower weight would help aswell. i flew 1106 3800kv motors on 2s with good results for flights in tight spaces, but my was about 90g and with a 450mah2s lipo lightweight in comparison. i got about 5minutes flytime. it was on a diatone grasshoper 160 frame - a 4inch frame sadly these hq 4025 wasnt available
about weight aswell, did you try different battery options?

I tried hover test again today with 3000mah 18650 3s pack. now AUW is 277gm.
Got 20 minutes+ flight time. Brought down voltage up to 7.5v (air)
Definitely flyable till 18 minutes at 70% hover throttle and voltage being 8.7V  under 10A current pull.
Now hover throttle range is from 55% to 70%.

But my goal is AUW under 250gm.
With smaller vtx, I could save some 10gm.
I still got to shed some 30gm weight. 
GPS and its mount taking around 15gm.

(12-Jan-2020, 02:50 PM)sim_tcr Wrote: I tried hover test again today with 3000mah 18650 3s pack. now AUW is 277gm.
Got 20 minutes+ flight time. Brought down voltage up to 7.5v (air)
Definitely flyable till 18 minutes at 70% hover throttle and voltage being 8.7V  under 10A current pull.
Now hover throttle range is from 55% to 70%.

But my goal is AUW under 250gm.
With smaller vtx, I could save some 10gm.
I still got to shed some 30gm weight. 
GPS and its mount taking around 15gm.

Nice build,hope you enjoy it. I have a question what antenna do you have installed?
THANK YOU

(12-Jan-2020, 04:42 PM)Armandoaulet Wrote: Nice build,hope you enjoy it. I have a question what antenna do you have installed?
THANK YOU

Rx is normal frsky r-xsr antenna.
VTX antenna whip antenna.

Super cool build! I just got all the parts to build something similar, even the 18650 batteries

in attempt to reduce weight, i made another frame with abs plastic mimicking original cf frame.
I saved 14gm. So now dry weight 114gm.
Arms were bit flexible. Any way I gave it a try with 3s first and 2s next.

With 3s, it sounded different, and current draw was also more than when i flown original frame and 3s. And within a minute motors got hot to touch. Did not continue further.

Then tried with 2s, it flown ok. same flight time of 13min  (original frame and 2s gave same results).

   

   

Any update flights? You are getting almost double my flight time and am enjoying your build adventure!

(21-Jan-2020, 02:38 AM)kaitylynn Wrote: Any update flights?  You are getting almost double my flight time and am enjoying your build adventure!

Yes I could easily get 10min+ on 2s and 15min+ on 3s.
With 2s there isn’t much room left with throttle . With 3s that’s improved but weight increased above 250gm.

Not sure if I can have a real outdoor flight soon. I don’t have any flying field close to me.
I can trying to put a video of indoor hovering.