I was reading comments on a review of the Beta85 (on Youtube) the other night and one of the people said he had swapped the original BetaFPV 1103 11000kv motors you get with it, for the 8000kv version (used on the Beta75X).  This yielded flight times between 5-9 mins on a 660mAh 2S pack and tamed the beast quite a lot.  It's a bit too spirited for me in its default setup and 3 min flight times are a bit short.  The 11000kv is apparently good for racing.  I'd prefer better flight times to how it runs now (touch throttle and it's heading towards outer space).

I can't find these motors locally, but Happymodel do 1103 7000kv motors, that are available.  Would they work as a substitute?  I can't find a spec sheet for the 7000kv motors, only the 6000kv, 8000kv and 12000kv.  But they are apparently the motors used on the 2-3S Larva X (according to happymodel.cn).

For now I'm restricting motors to 50% power in the hope of making it a bit more manageable.  At 90% it's scarily fast.  If 50% is too much i will try dropping it to 40%.


Thoughts?

No need replacing motors. Just reduce power as you have done while you are matching pace with the quad.

Its all about throttle discipline. I do not apply any throttle limits/scaling. You just need to calm your nerves and practice flying slowly/smoothly.

I have a 5" Racer style build where if I go aggressive I can drain a 6S lipo in 2 minutes. On the other hand on the same setup I can get 10 mins if I slow cruise (very gentle with the throttle).

I am still quite new to flying so haven't got it down yet, but find it quite disconcerting when I touch the throttle (and i'm not talking a lot), like what would be maybe a few percent and its screaming towards 30-40m high in seconds. I cut the throttle to zero and it took a good 5-6 secs to come back down, while testing yesterday. I could have disarmed, in which case it might have fallen out of the sky, but would prefer a controlled descent. It almost seems like at default I don't have that linear throttle control I see other pilots have. They push the throttle up to 10-20% and the drone takes off, but it's smooth, not like a rocket. On mine 10% is too fast.

I will try it on 50% later today and see how it handles.

Is throttle limit in BF the same as adjusting motor power? Or can this be used in tandem to create a more linear throttle behaviour?

I read Oscars page on Reducing Power and Capping Throttle and intend to try and setup the method using a potentiometer type knob, as I have two of them on my Jumper which are unused. It seems this might be a good use for one of them.

Thanks for the help Kafie1980.

Can you point me to exactly which article you are referring to that covers "Reducing Power and Capping Throttle"?

I do not user any throttle limits or scaling myself. So does it make the throttle more linear, I can't comment on the feel since I do not use it.

Now the part where you say it just shoots up has got me concerned. Do you have any form of an expo applied on the throttle or any custom curve you are using on the transmitter? Quad shooting up at 10% throttle seems a bit concerning unless you had a 10:1 power to weight ratio which is highly unlikely.

I used to run it on 60% motor power (recommended in a Captain Drone video) and upped that due to the windy conditions. So that probably accounts for some of the skittishness. No expo applied. Everything is mostly default. Only things I've altered in terms of the PID page was Angle/Horizon mode settings, to tame it a bit and they are at default currently.

From what i read and watched, this whoop is (dare I say it) somewhat overpowered, so a high thrust:weight ratio is definitely a possibility, but I can't find any exact numbers for these motors. The other things is probably because I fly these light 380mAh packs, I still retain the power. Maybe using 660 (32g) or 550 (29g) would counter some of the thrust. I don't have any so far, so can't test.

The article on Oscars site is this one: https://oscarliang.com/reduce-power-thro...etaflight/

I know in six months I probably won't use any of this all that much, but capping the throttle could be useful in certain places like playgrounds and when letting others fly.

Ok, in that case just use the Betaflight throttle limit as per Oscar’s post:

Set throttle_limit_type = scale
Set throttle_limit_percent = 80
Save

Reduce that based on your preference.

With the throttle_limit_type set to scale you should get more stick resolution.

2S to 1S doesn’t play well with most AIO boards but helps as well. I have flown 6S quads on 4S and loose top end speed but the flight times increase and I seem to plan my flight with more technical focus on improving my skills.

I wasn't planning on going to 1S. I have ordered a couple of 2S 660mAh packs. They weigh an additional 12g more than the 380's I fly at the minute. I've been meaning to do it for a while. Then i guess it's try, tweak, repeat.

I will also try the throttle_limit_type = scale and see if it smooths out the twitchy throttle. Also will try and setup the "Using Slider/Knob to Change Max Throttle (Mixer Multiplex)" method, so i can adjust it on the fly. If it's a windy day, I might need a bit more.

Thanks for your help Kafie. I now have some ideas to try.

the larva x is used on 2,5", a different world about efficiency.
to gain better flighttimes on that small rotorsizes, low weight/lower rpms are more important than capacity. i would suggest a turnigy nanotech 2s 300mah. i used exactly that combination on a pusher whoop in the past - it wont come to good flighttimes but some more flighttimes and general better flightabilities and response

I'm hoping that scale option will smooth out the throttle a bit. That is the main issue, beyond all others. I kind of want my throttle to be smooth and slow, so full power is at max throttle and minimum throttle doesnt make the drone fly at insane speeds. Flight times, yeah if it flew for 7 mins that would be sweet, but better handling is more important for now. So I can learn to handle the insane speeds.

On a side note, does anyone know where I can get motor mounting screws and especially what size. They are insanely small. One of mine has fallen out and BetaFPV in their infinte wisdom put only 2 screws in each motor instead of 4 (and didn't put any spares in the box). If i'd known, I would have locktite'd them all, but i'm new to all of this.

I finally found the spec info.

Quote: 1103 11000KV Motors

Shaft diameter: 1.5mm
Axis length: 6.4mm
Motor mount holes: 8.5mm
Size of motors: 13.5mm*13.5mm*16mm
Weight: 3.25g/pcs
Pull: 23-40g
Power: 6.7-28W
Efficient: 3.4-1.4g/W

Usually they are M1.4 or M2.

This is why I have been hoarding screws and fasteners for years as finding any below M3 in the correct length can be a huge challenge.

I've ordered M2 screws in 4-8mm lengths. Hopefully one of those will work. If not I will order some 1.4s and try again.