Mini-2 vs Mini SE

[Chaosrider]

I can second @scro info on the Tello. It is the closest you will get to a 'real' drone for the cost/value. As has been mentioned, it has a very good camera for the price. @Chaosrider you should really check out the TelloPilots forum and ask your questions over there as you will get lots of great feedback on your questions over there.

Chris

I didn't know there was a Tello Pilots forum! I'll go check that out at some point.

Thx,

TCS

 

[vindibona1]

The only thing that affects wind resistance is the max speed of the drone...
The speed of the drone is all you need to know.

That's what I think as well. The Beufort scale is relatively useless. What new pilots need to know is the max speeds in each mode of their drones and comparisons of those speeds between different models. If you have a a 20mph wind and your max speed flying into it is 20mph, your drone is going nowhere at full throttle and will run out of batteries while going nowhere. If the wind is 18mph and you're flying into it with the rating of 20mph, it will move at 2mph.

Getting back to having been challenged on this, there IS a difference in the power of the Mini 2 vs the SE as well as PRACTICAL wind resistance, not just hovering in the wind. The Mini 2 is significantly less likely to be blown away than an SE. The Mini 2 has 19% more power than the SE in a practical real world sense.

 

[Crash and Burn]

While I saw that the "rating" was the same as the Mini 2, the max speed indicates otherwise. As I understand it max speed vs wind is what determines true wind resistance. SE speeds displayed on the right, Mini 2 on the Left
36mph max speed/Mini 2/sport mode. 29mph max speed/SE/Sport mode. Bottom image is Mavic Mini (1). Same speed rating as SE. I think someone got a little over-eager or made a typo when they rated the wind resistance of the SE as a 5. I don't see how that can be unless somehow they adjusted the attack angle, but I don't think that's the case.

View attachment 142876
View attachment 142877

There's a thread where this is discussed in detail and people who actually own an SE have tested and contributed their thoughts. Wind Test?

Ann

 

[cheddar-man]

Why does speed matter so much?
Right now I have both SE (for sale) and a 2. Both excellent drones but the biggest difference for me is the control distance and here the 2 far outstrips the SE. Flying from the same place I had solid control of the 2 at double the distance of the SE (for sale)

 

[scro]

Speed determines what wind resistance the drone has. Regardless of how solid a control signal you have, if it's too windy for your drone you can't fly - that's why speed matters

The Mini 2 has a much better control signal range than the Mini 1 and Mini SE. However, in practice, I find the Mini 1 control signal is generally reliable out to the limits of VLOS and often well beyond. I've very very rarely felt the need for a more reliable signal for the kind of flying I do. On the flip-side I have wished for more power/better wind resistance on numerous occasions.

 

[vindibona1]

There's a thread where this is discussed in detail and people who actually own an SE have tested and contributed their thoughts. Wind Test?

Ann

Yes. And most of the posts confirm what I ascertained in my reply. DJI implying that the wind resistance of the SE by changing the Beaufort scale rating from the Mini1 to the SE is disingenuous. How could one drone with a lower max speed possibly have the same wind resistance as one that could fly 20% faster?

 

[Chaosrider]

The Mini 2 is significantly less likely to be blown away than an SE. The Mini 2 has 19% more power than the SE in a practical real world sense.

This is interesting.

What values go into making that power comparison?

I haven't flown a Mini-SE yet, but my Mini-2s seem almost impervious to the wind. Of course, I don't fly in storms much...

Thx,

TCS

 

[Chaosrider]

Why does speed matter so much?
Right now I have both SE (for sale) and a 2. Both excellent drones but the biggest difference for me is the control distance and here the 2 far outstrips the SE. Flying from the same place I had solid control of the 2 at double the distance of the SE (for sale)

Thank you for this!

The control signal on my Mini-2s starts to drop substantially at about 3000 ft. So this suggests that, in my terrain and signal conditions, the Mini SE should get about 1500 ft.

Greatly less, but still respectable.

TCS

 

[scro]

What values go into making that power comparison?

The mini 2's max speed of 16m/s is approximately 19% faster than the Mini SE's top speed of 13m/s. Being pedantic, actual power of the mini 2 is probably more than a 19% increase on the SE

I have a mini 1 and that has a top speed of 13m/s. The firmware limits this to a ground speed (ie GPS speed) of 13m/s too as you can't really push past this by flying downwind even in a good breeze. The mini 1 most likely lacks thrust reserves to get past an airspeed of 13m/s. In weight lifting tests the mini 2 demonstrates it has significantly more thrust than the mini 1 (approx 280g vs 180g, from youtube videos). I've not come across a test where someone has quantified the amount of thrust reserves the Mini SE has. This would give a good indication of its ability to resist wind compared to the MM1 and Mini2 since thrust is the one thing that matters. With the SE being the current "base model" in the DJI lineup there's every possibility that the max speed has been limited so as not to encroach on the Mini 2's specs too far. Many other aspects of the drones have been "crippled" slightly to maintain DJI's preferred hierarchy of drones.

 

[vindibona1]

This is interesting.

What values go into making that power comparison?

I haven't flown a Mini-SE yet, but my Mini-2s seem almost impervious to the wind. Of course, I don't fly in storms much...

Thx,

TCS

I think you are asking how does a company come assign a Beaufort Scale number? I think it's largely subjective. Obviously for a company wanting to sell a product, if there are shades of gray they're going to make it look as good as they can on paper. Below is a shot of the Beaufort Scale and if the SE can fly at 29mph in sport mode the SE technically falls into the Scale 5 category. But then using this standard the Mini 2 with a top speed of 36mph could be assigned a scale 6 or 7. But that's not realistic.

The Mavic 2 Pro with a max speed of 45mph (72kph) does not have an official Beaufort rating on the DJI spec sheet, but some peg it at Scale 5. DJI does stated the max wind resistance as copied/pasted below.

It seems highly unrealistic for the two drones, one that can fly 90% faster than the other with much more power to have the same Beaufort Scale rating. The other thing to consider is gusts and out inability to judge the intermittence or consistent force of any gust. As an example, right now I'm looking at UAV Forecast and wind is at 12mph but gusts double that at 24mph. Seems fine for a Mini 2 or SE based on Beaufort. But at 250 feet the wind is noted at 18mph and 28mph gusts. Bottom line, for me personally in the current wind conditions I'd be ok flying my Mavic 2 Pro (which is largely why I bought it), *might* take a chance on the Mini 2... but my Mini 1/SE would be grounded. JMO

MAVIC 2 Max Wind Speed Resistance	18mph-24mph/29–38 kph

 

[Chaosrider]

The mini 2's max speed of 16m/s is approximately 19% faster than the Mini SE's top speed of 13m/s. Being pedantic, actual power of the mini 2 is probably more than a 19% increase on the SE

I have a mini 1 and that has a top speed of 13m/s. The firmware limits this to a ground speed (ie GPS speed) of 13m/s too as you can't really push past this by flying downwind even in a good breeze. The mini 1 most likely lacks thrust reserves to get past an airspeed of 13m/s. In weight lifting tests the mini 2 demonstrates it has significantly more thrust than the mini 1 (approx 280g vs 180g, from youtube videos). I've not come across a test where someone has quantified the amount of thrust reserves the Mini SE has. This would give a good indication of its ability to resist wind compared to the MM1 and Mini2 since thrust is the one thing that matters. With the SE being the current "base model" in the DJI lineup there's every possibility that the max speed has been limited so as not to encroach on the Mini 2's specs too far. Many other aspects of the drones have been "crippled" slightly to maintain DJI's preferred hierarchy of drones.

So, you calculated the (relative) power from the performance figures, and not from any actual measurement of engine power. That can be a crude indication, but there can be a lot of things that impact performance besides engine power. For example, if your hypothesis about DJI limited the Mini SE is correct, that could be done via firmware, rather than a reduction in engine power. In that event, it would have a lower speed, but might have the same ability to fight wind, which requires power and not speed.

Did I miss anything?

Thx,

TCS

 

[Chaosrider]

I think you are asking how does a company come assign a Beaufort Scale number? I think it's largely subjective. Obviously for a company wanting to sell a product, if there are shades of gray they're going to make it look as good as they can on paper. Below is a shot of the Beaufort Scale and if the SE can fly at 29mph in sport mode the SE technically falls into the Scale 5 category. But then using this standard the Mini 2 with a top speed of 36mph could be assigned a scale 6 or 7. But that's not realistic.

The Mavic 2 Pro with a max speed of 45mph (72kph) does not have an official Beaufort rating on the DJI spec sheet, but some peg it at Scale 5. DJI does stated the max wind resistance as copied/pasted below.

It seems highly unrealistic for the two drones, one that can fly 90% faster than the other with much more power to have the same Beaufort Scale rating. The other thing to consider is gusts and out inability to judge the intermittence or consistent force of any gust. As an example, right now I'm looking at UAV Forecast and wind is at 12mph but gusts double that at 24mph. Seems fine for a Mini 2 or SE based on Beaufort. But at 250 feet the wind is noted at 18mph and 28mph gusts. Bottom line, for me personally in the current wind conditions I'd be ok flying my Mavic 2 Pro (which is largely why I bought it), *might* take a chance on the Mini 2... but my Mini 1/SE would be grounded. JMO

MAVIC 2 Max Wind Speed Resistance	18mph-24mph/29–38 kph

View attachment 143169

Well, this wasn't what I was asking about, but it's independently interesting!

Assuming the "Effects" column is accurate, I've flown my Mini-2 in Level 7 winds on several occasions. By that I mean entire large pine trees were waving around, and you definitely got resistance walking in the wind.

That's not really surprising in this canyon. Clear Creek Canyon is the atmospheric drainage point from the Lake Tahoe basin into the Carson Valley. If the Tahoe Basin is getting 30 mph winds, we'll easy see 50 mph in this canyon, and not steady either. Sometimes, the wind will set up weird low frequency standing sound waves as it bounces around in the canyon, and they will rattle the walls of my house, not just the windows.

As my previously posted crash video shows, flying in those conditions next to moving big tree branches isn't really a good idea...

;-)

Next month I plan to trade one of my Mini-2s for a Mini SE, so I'll be able to do some apples-to-apples wind resistance comparisons in my actual conditions.

Thx!

TCS

 

[scro]

So, you calculated the (relative) power from the performance figures, and not from any actual measurement of engine power. That can be a crude indication, but there can be a lot of things that impact performance besides engine power. For example, if your hypothesis about DJI limited the Mini SE is correct, that could be done via firmware, rather than a reduction in engine power. In that event, it would have a lower speed, but might have the same ability to fight wind, which requires power and not speed.

Did I miss anything?

Thx,

TCS

It's the relative speeds, and not relative power. How much deadweight each drone can lift is a better indication of power, and also thrust. The Mini SE may or may not have its top speed limited by firmware. If it does have a speed limiter then that would explain the improved wind rating compared to the mini1.

I've flown my Mini 1 in what would be classed as 5 on the Beaufort scale. I could tell it was about at its limit, but it could still make headway into the wind, and reliably hold position in a hover. However, I think it might be a bit ambitious to say it can fly well in those conditions.

 

[Meta4]

In that event, it would have a lower speed, but might have the same ability to fight wind, which requires power and not speed.

The drone's speed is what matters.
A faster drone can push through the air faster.
The drone's top speed in still air gives a correct indication of how it can deal with wind.

 

[Meta4]

The Mini SE may or may not have its top speed limited by firmware.

All current DJI drones have their top speed limited by firmware.
Speed is dependent on the forward tilt angle and the max tilt angles are set in firmware.
And all models have an additional limit that prevents them getting more than a tiny boost in speed with a tailwind.

 

[scro]

All current DJI drones have their top speed limited by firmware.
Speed is dependent on the forward tilt angle and the max tilt angles are set in firmware.
And all models have an additional limit that prevents them getting more than a tiny boost in speed with a tailwind.

While not wrong, this is a little misleading. As standard the mini1 has a firmware limited max tilt of 30degrees. At its maximum speed in still air the mini 1's tilt is typically around 25deg. Clearly the firmware set tilt limit is not what is preventing the drone going faster. Further evidence to support this is the fact that the drone does not fly any faster when the firmware tilt limit is increased beyond 30deg.

There are 2 possible explanations as to what is limiting the mini1's top speed:

1. There is a groundspeed limit set in firmware. This would explain why the drone can't fly faster downwind: GPS senses that the max groundspeed has been achieved so backs off the tilt to prevent any higher groundspeed, even though the airspeed is well below the maximum the drone is capable of. If the groundspeed firmware limit is less than the max airspeed the drone is capable of then the drone could resist wind beyond its stated max speed. A mismatch between the max airspeed and a firmware groundspeed limit would also manifest itself by the drone being able to hit top speed when flying into a light breeze. It takes almost no wind for a slight reduction in top speed when heading into the wind with the Mini1 so this can bring us to the conclusion that any firmware groundspeed limit is aligned with it's maximum airspeed. With more powerful motors than Mini1 yet same stated max speed, the Mini SE may have a mismatch.
2. The drone cannot produce enough thrust to go any faster. Some of the total thrust is required to keep the drone airborne, and this amount required could vary with a combination of tilt and airspeed as the body of the drone at different tilt angles could produce some uplift or downthrust. The rest of the available thrust can be used for pushing the drone forwards through the air up to a max forward speed. More powerful motors means more total thrust, and hence more available for pushing the drone forwards once the "baseload" thrust for keeping airborne has been accounted for.

 

[Meta4]

There are 2 possible explanations as to what is limiting the mini1's top speed:

• There is a groundspeed limit set in firmware. This would explain why the drone can't fly faster downwind: GPS senses that the max groundspeed has been achieved so backs off the tilt to prevent any higher groundspeed

All DJI drones have had the anti-tailwind limit since 2015.
But when not flying with a tailwind, the only limit is the tilt angle.

• The drone cannot produce enough thrust to go any faster.

The Mini was always underpowered which is why it was quickly replaced by the Mini 2
In normal mode it can only manage 8 metres/sec

 

[scro]

But when not flying with a tailwind, the only limit is the tilt angle.

How do you come to that conclusion? It goes against the observed and measured behaviors presented in post #36. Acrobatics/FPV drones very often have NO limit on the tilt angle, but they definitely have a limit on their top speed, and that is dictated by the thrust they can produce. On typical DJI drones like the mini 1, SE, 2 etc max speed is a combination of tilt angle limits AND available thrust.

Also, what is the relevance of presenting the normal mode speed of 8m/s in the context of power? The MM1 can "only manage" that speed due to firmware limits, not due to it being underpowered. I fully agree the MM1 is limited by its power (and could do with more), but then so is the SE and Mini2. In the case of the Mini2 that limit is raised sufficiently that its capabilities are better aligned with typical people's expectations.

 

[Meta4]

How do you come to that conclusion?

From analysing the flight data from many Mini flight incidents and knowing how other DJI drones work.

It goes against the observed and measured behaviors presented in post #36. Acrobatics/FPV drones very often have NO limit on the tilt angle, but they definitely have a limit on their top speed, and that is dictated by the thrust they can produce. On typical DJI drones like the mini 1, SE, 2 etc max speed is a combination of tilt angle limits AND available thrust.

Also, what is the relevance of presenting the normal mode speed of 8m/s in the context of power? The MM1 can "only manage" that speed due to firmware limits, not due to it being underpowered. I fully agree the MM1 is limited by its power (and could do with more), but then so is the SE and Mini2. In the case of the Mini2 that limit is raised sufficiently that its capabilities are better aligned with typical people's expectations.

Sorry ... you've lost me, I can't tell what you are getting at.
The Mini is low powered and DJI set a lower Max tilt angle for it than for other DJI drones.
If I had to guess that the tilt angle is less because the thrust from it's motors is less.

 

[scro]

So, if max tilt, and only max tilt is what dictates top speed then why does my mini1 not use its max tilt of 30deg when flying at its top speed in still air or into a slight headwind? Also, why does it not go faster if the max tilt limit is increased to, say, 40deg? I have tried modifying the firmware to increase the tilt limit, and observed the drone use the full 40deg tilt - just never at max speed. From your many mini1 flight analyses, what tilt angles are you typically seeing when the drone is cruising at max airspeed?

Sure, tilt angle has a big influence on top speed (no tilt = no speed) but available thrust is clearly very relevant too. The mini1 has quite limited thrust so it is easy to observe the drone reach it's limits due to thrust. The mini2 has significantly more thrust so can make use of greater tilt angles. I've not seen a reliable assessment of the thrust the Mini SE has, but I expect it is more than the Mini1, and hence can make better use of its 30deg tilt limit.