UDI U841 (In-Depth Review)

The UDI U841 is a micro quadcopter that has a diagonal rotor size of 100mm and comes with a few unique features that sets it apart from other quads in the same class. At first glance, the 6-axis U841 appears to be another Hubsan X4 clone as it seems to have roughly the same propeller size, motor and dimensions. But upon closer examination you’ll notice that the motors are slightly larger than your average X4 and when you throttle it up, it becomes apparent that this is no X4 clone by any means.

Thanks to the larger and more powerful motors which are some of the biggest I’ve seen so far on a 100mm-size micro quadcopter, the U841 has a far more punchy throttle response and a lot more reserve power compared to the ubiquitous X4. The extra power also means the U841 is very precise in the way it flies and super easy to control. But more powerful motors also means a power-hungry drone and although the U841 comes with a 3.7V 450mAh battery, it has an average flight time of a little over 7 minutes without any payload. In contrast, the X4 comes with a 240mAh battery and has an average flight time of about 9 minutes (without payload).


Despite its shorter flight time, I’d still choose the U841 over an X4 anytime when flying indoors — those powerful motors can be quite addictive. Put the U841 against a X4 in a vertical drag race and the U841 will easily smoke the X4 anytime.


The U841 is also more than just a little micro quad with powerful motors. It comes with a set of propeller guards that double as wheels, giving the U841 some unique features such as the ability to “climb” walls and ceilings as well as rolling on the ground like a small RC car.


  • Size: 100mm (diagonal)
  • Weight 64g (with battery, micro SD card and standard prop guards)
  • Battery: 3.7V 450mAh Li-Po
  • Flight time: 7 minutes (no payload), 2-3 minutes (with video recording and prop guards)
  • Dimensions: 176.5 x 140 x 60.5 mm
  • Control range: Up to 30m
  • Control frequency: 2.4GHz
  • Maximum memory card support: 64GB
  • Video recording modes: HD 1280 x 720p
  • Max bitrate of video storage: 30 Mbps
  • Supported file formats: FAT32, Photo: JPEG, Video: AVI

I’m a big fan of UDI’s quadcopter designs. The entire range of UDI products have an overall aesthetic appeal that is a lot more refined than what the average drone maker has to offer. If you take some time to contemplate on any UDI product, you’ll notice that extra effort has been put into its looks and styling.


The U841 is no exception to this. It almost looks like a black mini Lamborghini with white racing stripes, four small propellers and a pair of menacing blue “headlights”. In my opinion, the U841 is one of the most good looking micro quadcopters around today. It also comes with a really nice radio transmitter that looks as good as it feels.

The flexible plastic used on the U841 and its prop guards appears to be the same plastic used in the UDI U818A which is known to be somewhat immune to abuse. That said, I believe the U841 is one very tough micro quadcopter that can survive extremely hard crashes and knocks.

Strip all that extra weight and the U841 becomes a mini beast of a quadcopter.

Each U841 comes shipped with an extra set of propellers, 3 different sets of prop guards, a USB charger, a 2GB micro SD card and a USB micro SD card reader. My unit came with an extra battery which was great since this little quad drains batteries pretty fast.

Not your average micro quadcopter

The U841 is unique from other micro quadcopters by its special flying configurations. Besides the standard prop guards, the U841 also comes with 2 sets of special prop guards that also double as wheels. The first is a set of four small wheels that attach to the sides of the quad, allowing it to skim the ground like a RC car. The second set consists of two large “Ferris” wheels that allow the U841 to “climb” up walls and move against ceilings. I find the U841 hardest to control when having those large Ferris wheels on although it can appear deceivingly easy to fly in its promotional videos. Hit a wall or hard surface too fast and the propellers will rub against the large wheels. Due to their bigger size, these wheels are also the heaviest props which means shorter flight times.

The U841 can be flown in 4 different configurations.

Apart from these special prop guard configurations, the U841 has all the standard features of typical micro quadcopters. This includes the ability to flip. By pressing down the right stick inwards, the transmitter will start beeping which indicates the quad is ready for a flip. Pushing the right stick in any direction will make the quad flip in the direction you chose.

The transmitter is powered by 4 pieces of AAA batteries and comes with a mini LCD screen that shows you how much battery power it has, radio signal strength, throttle trims, gyro sensitivity level and throttle level. The transmitter has good ergonomics and feels really good in your hands — a far cry from the cheaper transmitters that often come with other micro quadcopters.

The U841 can fly at 3 different gyro sensitivity levels — Low, Medium and High. In “Low” mode, the U841 will fly slower and is easier to control while “High” will unleash the full power of its motors. To toggle between levels, press the left stick inwards.

The U841 also comes equipped with a built-in 720P HD camera for recording stills and video at 30fps.


Due to its unique prop guards and because it was released only a few months ago, the U841 carries a price tag that’s slightly higher than the competition (it currently costs about $60 with shipping). However, in the coming months it should become more affordable.

The U841 looks great in white and red too.

This is a powerful little quad that I’d recommend if you want to fly mostly indoors. The power and raging sound of its motors will convince you it’s not your ordinary 100-size quadcopter. Due to its powerful motors, the U841 has a lot of traction and responses fast to stick movements unlike other quads with smaller motors that tend to feel a bit sedated.

Those bigger motors also have their drawbacks. Due to higher power consumption, the U841 has less than average flight times. Without any payload, it can fly for about 7 minutes. With video recording turned on and prop guards attached, it gets a paltry 2 to 3 minutes of flight time.

More power on the motors also means more damage on the propellers whenever you crash. Despite having prop guards attached, the U841 can still grind its propellers really hard whenever you crash. Always remember to throttle down whenever you think a crash is inevitable to avoid grinding your propellers.

Other than these minor issues, the U841 is really a fantastic micro quadcopter to own and fly. Whether you’re flying just for fun or whether you’re using it as a trainer drone — the U841 won’t disappoint. It’s also a drone that can operate fairly well in tight spaces thanks to its size and control precision.

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