Are the Mini2 motors actually more powerful than the Mini1?

[scro]

I think you could do that with ATTI mode -- it turns off GPS position hold but leaves altitude hold on.

You're correct, but on the Mini you can't remotely put the drone into atti mode, like some of the larger mavics. You can fudge atti mode indoors by covering the VPS sensors with tape, and outdoors with a piece of foil over the front top of the drone where the GPS receiver is.

 

[RogerDH]

You're correct, but on the Mini you can't remotely put the drone into atti mode, like some of the larger mavics. You can fudge atti mode indoors by covering the VPS sensors with tape, and outdoors with a piece of foil over the front top of the drone where the GPS receiver is.

Ah, thanks -- I only vaguely remembered that there was some way to get the Mini to use ATTI mode, but that's not a particularly graceful solution, is it.

 

[EyesWideShut]

Ah, thanks -- I only vaguely remembered that there was some way to get the Mini to use ATTI mode, but that's not a particularly graceful solution, is it.

@RogerDH , Litchi beta for the original Mini has the option in settings to turn off "Landing Protection" and/or "Visual Positioning System (VPS)" which gets you close to a true "ATTI Mode". I wish it also had an option to also turn off GPS to put it into full ATTI.

*** Caution*** I was flying with the Fly App outdoors in no wind conditions and the mini wasn't holding it's position very well and found out that by having the VPS turned off in Litchi, it was also turned off using Fly. Problem was solved when I went into Litchi and turned the sensors back on. Wonder if it was because I had just closed Litchi and opened Fly without turning off my device and AC?

 

[DanMan32]

7.2V, 7.7V, 8.0V, it's all marketing. Charge and measure. 8.4V.

The MM2 measures 8.4v after being charged by an MM2 AC or hub? It's supposed to be 8.8v.

There are different versions of LiPo, and I believe 4.4v are the HV versions.

 

[RogerDH]

The MM2 measures 8.4v after being charged by an MM2 AC or hub? It's supposed to be 8.8v.

There are different versions of LiPo, and I believe 4.4v are the HV versions.

Yep, by DJI's specs, you're right: They must be HV, 4.4v max charge and 3.85v average discharge for each cell.

 

[OregonEd]

Well, the batteries are 7.7V instead of the original 7.2V, so even if they used the same motors, they would have more power available.

I'm not an engineer so I don't know squat about technical things, but will note that the Mini1 has a top speed of 26mph in sport mode while the Mini2 has a top speed of 35mph. Some of that has to do with increased pitch angle, but I suspect some has to do with increased volatage and possibly stiffer propellers.

Does anyone know what the maximum speed of the MM1 is using Drone-Hacks?

 

[scro]

Does anyone know what the maximum speed of the MM1 is using Drone-Hacks?

I've achieved 14.7m/s horizontal speed with tilt set to 40deg. It only seems to use the full 40deg tilt for initial acceleration. At top speed it had reduced tilt to between 15-20deg. Vertically I've achieved 6m/s reliably, which beats the Mini2's 5m/s.

 

[RogerDH]

I've achieved 14.7m/s horizontal speed with tilt set to 40deg. It only seems to use the full 40deg tilt for initial acceleration. At top speed it had reduced tilt to between 15-20deg. Vertically I've achieved 6m/s reliably, which beats the Mini2's 5m/s.

I wonder if it backs off on the tilt if it detects altitude loss?

 

[EyesWideShut]

I wonder if it backs off on the tilt if it detects altitude loss?

There's another thread somewhere here where the operator was flying the mini 2 over the Snake River into a very strong wind and put it into sport mode and full tilt forward towards home. The extreme tilt into a strong wind may have been the cause of the drone unable to maintain altitude and forward motion and pushed the drone seriously lower.

 

[dwallersv]

Power consumed might be V x I, but useful power out needs to consider whether these 2 are in phase or not.

Not sure what you're driving at.

Energy is conserved. Therefore, V x I power will be dissipated, regardless of the dynamics of the the two factors. If the voltage pulses are out of phase in the motor, it will draw less current.

 

[dwallersv]

Just a quick note about batteries. 7.2V vs 7.4V is just nonsense. Lithium Ion batteries have a range between 2.5-3V at the low end, and 4.2V at the high end. This is a limit of Li-Ion chemistry. Going out of this range shortens the battery life significantly. In general, 3.6V is considered the average Voltage for a cell, and 7.2V is twice that (Two cells). I can guarantee you there will be no measureable difference between a fully charged '7.2V' battery and a '7.4V' battery, because fully charged they will both measure 8.4V.
The new battery might have a slightly higher Amp Hour rating, but it won't be much, considering they both appear to use 18650 cells.

There are two different formulations in widespread use, the older design with a peak charge voltage of 4.2V, and a newer formulation that charges to 4.35V, and has a corresponding higher flat discharge region. In terms of stored power, the difference is significant.

 

[OregonEd]

I wonder if it backs off on the tilt if it detects altitude

I've achieved 14.7m/s horizontal speed with tilt set to 40deg. It only seems to use the full 40deg tilt for initial acceleration. At top speed it had reduced tilt to between 15-20deg. Vertically I've achieved 6m/s reliably, which beats the Mini2's 5m/s.

32.88 mph, thanks scro. Anyone faster?

I believe that the maximum speed is limited by dji and without a hack or tail wind, only the acceleration can be increased with the parameters.

 

[OregonEd]

I've achieved 14.7m/s horizontal speed with tilt set to 40deg. It only seems to use the full 40deg tilt for initial acceleration. At top speed it had reduced tilt to between 15-20deg. Vertically I've achieved 6m/s reliably, which beats the Mini2's 5m/s.

38.22 mph, thanks scro. Anyone faster??

 

[scro]

I wonder if it backs off on the tilt if it detects altitude loss?

It may have something to do with getting close to the max motor speed. At 40deg tilt fwds the rear motors are exceeding 16k rpm often. Maybe one day I'll do a few more test flights and analyse the logs.

 

[scro]

Not sure what you're driving at.

Energy is conserved. Therefore, V x I power will be dissipated, regardless of the dynamics of the the two factors. If the voltage pulses are out of phase in the motor, it will draw less current.

I've not used my electrical engineering knowledge for a long time so maybe best I stop talking about "imaginary numbers" and "imaginary power"? before I start imagining other things too?

 

[Murdoch]

I bought a pair of mini 2 props for my mini to test if the prop geometry is making the mini 2 faster and more quite. I am a tool and die maker/design engineer and measured everything up. The mini height of the hub is .184 compared to the mini 2 measures longer at .219. Hub diameters are the same .232. Hub counterbore diameters are .196 for the mini and .168 for the mini 2. A side by side comparison of the shape of the blades is almost identical with the exception that the mini 2 is much stiffer when bending by hand. The thickness of the blades measure the same so they must use a different plastic. The screw diameters are .090 for the mini and .093 for the mini 2. Thread sizes are different. My plan is to make a fixture at work to mod the mini 2 props to accept the mini screws. I need to do a few more measurements at work. If it works i could make more sets. It may be a few weeks before I would have the time at work to do this so please be patient on the results.

 

[RuudF]

If you judge the capability to handle wind velocity there is a difference between the mini and the mini 2.
Mini up to 28,8 km/h Mini 2 up to 38 km/h.
Max speed in sport mode Mini 46,8 km/h and Mini 2 57,6 km/h.

In answer to the question is there a difference between the motors: yes there is!

Ruud

 

[scro]

If you judge the capability to handle wind velocity there is a difference between the mini and the mini 2.
Mini up to 28,8 km/h Mini 2 up to 38 km/h.
Max speed in sport mode Mini 46,8 km/h and Mini 2 57,6 km/h.

In answer to the question is there a difference between the motors: yes there is!

Ruud

I think this analysis misses one important difference between the 2 models: The mini 1's maximum tilt is firmware-limited to 30deg, whereas the mini2 is allowed to tilt up to 40deg.

Increasing tilt from 30deg to 40deg gives approximately 30% more thrust in the horizontal direction, which would clearly have a significant effect on maximum speed and wind handling capability.

The mini1 has ample reserve power to handle more tilt than 30deg.

 

[TDZHDTV]

I bought a pair of mini 2 props for my mini to test if the prop geometry is making the mini 2 faster and more quite. I am a tool and die maker/design engineer and measured everything up. The mini height of the hub is .184 compared to the mini 2 measures longer at .219. Hub diameters are the same .232. Hub counterbore diameters are .196 for the mini and .168 for the mini 2. A side by side comparison of the shape of the blades is almost identical with the exception that the mini 2 is much stiffer when bending by hand. The thickness of the blades measure the same so they must use a different plastic. The screw diameters are .090 for the mini and .093 for the mini 2. Thread sizes are different. My plan is to make a fixture at work to mod the mini 2 props to accept the mini screws. I need to do a few more measurements at work. If it works i could make more sets. It may be a few weeks before I would have the time at work to do this so please be patient on the results.

Just get some of these from eBay, you’ll probably be able to cut a new thread or adapt

 

[dwallersv]

I've not used my electrical engineering knowledge for a long time so maybe best I stop talking about "imaginary numbers" and "imaginary power"? before I start imagining other things too?

No sweat, my friend. Pure happenstance, you got into a discussion of brain surgery with a brain surgeon. I'm an EE (among other credentials).

As an aside, I'm an old one too (58). Old enough to be permanently amazed by how cool BLDC motors are, something that couldn't exist before we had the chip fab technology to make controllers small and fast enough to make them work.

Before that, people who specialized in DC motors were experts in BRUSHED motors. When I was a kid, I had a period of slot-car fandom, and remember well the technical details and mods to these motors.

My my my how things have changed ?