In this review, we’re checking out the Sub250 Whoopfly16, a durable Tiny Whoop-style micro FPV drone designed for both novice and experienced indoor pilots. Sharing many components with its sibling, the Nanofly20, this nimble drone sets itself apart with smaller 1.6-inch (40mm) tri-blade Gemfan propellers. We’ll delve into the Whoopfly16’s features, specifications, and performance to provide a comprehensive understanding of what it has to offer.
Interested in exploring the best Tiny Whoop drones and accessories available in the market? Check out this comprehensive round-up: https://oscarliang.com/best-tiny-whoop/
The Whoopfly16 is the second quadcopter we’ve reviewed from Sub250, following the exceptional Nanofly16, a micro drone we highly recommend for its performance: https://oscarliang.com/sub250-nanofly16/
Table of Contents
Where to Buy
The Sub250 Whoopfly16 comes with two receiver options: ExpressLRS or Crossfire. We are testing the Walksnail/ELRS version. Try using the coupon code “Sub250FPV10” for a 10% discount at the Sub250 store:
- Walksnail Version (Sub250): https://oscarliang.com/product-qxcy
- HDZero Version (Sub250): https://oscarliang.com/product-jlum
- Analog Version (Sub250): https://oscarliang.com/product-y2ub
- AliExpress: https://s.click.aliexpress.com/e/_DFl4DId
Please note that batteries are not included. You can purchase them here:
- Sub250 1S 530mAh: https://oscarliang.com/product-ks7h
- GNB 1S 550mAh: https://s.click.aliexpress.com/e/_De4lTst
What’s Included in the Box：
- Whoopfly16 drone
- USB Walksnail VTX cable for firmware updates
- Spare set of Gemfan propellers
- Two extra sets of foam bumpers
- A small Phillips screwdriver
- Allen wrench
- A few extra motor mounting screws
- Documentation for flight controller and VTX
Key Features and Specifications
- Motors and Propellers: The Whoopfly16 is equipped with 1002 21000KV motors and Gemfan 1608 40mm tri-blade propellers in an inverted, pusher configuration.
- Flight Controller: The drone features an F411 AIO flight controller with ICM42688P Gyro and a micro USB port, as well as a built-in ExpressLRS SPI receiver.
- Battery Connector: The Whoopfly16 uses a GNB27 connector and is recommended to pair with 1S 530mAh batteries that have a GNB27 connector.
- Video System: The drone comes with a Walksnail Avatar VTX, a 1S camera, and a whip antenna for video transmission.
- Frame Design: The Whoopfly16’s frame includes a unique battery tray, foam bumpers as prop guards, and an adjustable camera angle.
- Weight without battery: 42.9 grams
- Weight with 1S 530mAh battery: 55.7 grams
A Closer Look at the Whoopfly16
Left: Nanofly16, Middle: Whoopfly16, Right: Mobula7
The Whoopfly16 is a 75mm Tiny Whoop with a similar size to the Mobula7. However, the image quality provided by the Walksnail VTX is unparalleled when compared to analog video transmission.
FPV System Options
The Whoopfly16 is available with three different FPV setups: analog, HDZero, or Walksnail. Our version features the Walksnail VTX, which delivers HD video quality comparable to the DJI system. In my opinion, the Walksnail image quality is slightly better than HDZero, though HDZero has lower latency. You can learn more about the differences between FPV systems in this article: https://oscarliang.com/fpv-system/
The drone has a good camera tilt angle adjustment range. For indoor flying, I adjusted it all the way down for slower cruising. However, I found that the VTX dipole antenna provided less range and penetration than the circular polarized antenna found in the BetaFPV Meteor75, a competitor drone with a similar setup.
Frame
The WhoopFly16 features a strong, rigid plastic frame that feels more durable than the Meteor75’s more flexible frame. Foam tape around the ducts helps cushion impacts during crashes. The clean build includes motor wires taped down to the frame and air vents for VTX cooling. Additionally, the camera is well-protected within the canopy. However, the frame’s edges are visible in the video due to the camera’s wide-angle lens.
The prop guard (ducts) and canopy are molded into a single plastic piece. The ducts more rigid and sturdy than those on the Meteor75.
Battery Mount
The stiff battery mount, made from the same material as the frame, ensures a snug fit for the battery, preventing it from dislodging during crashes.
The Whoopfly16 uses a GNB27 battery connector and is recommended to pair with a 1S 530mAh battery. Official specs suggest a flight time of four and a half minutes, but our tests resulted in less flight time, even indoors without wind (see flight performance section for detail).
The battery mount is designed for the same battery size as the TPU battery holder in the Sub250 Nanofly16, making it compatible with batteries of this standard size from different brands and capacities. However, I much prefer the TPU battery holder for its flexibility and ease of use. The Sub250 branded 1S 530mAh LiPo weighs 12.8g
- Get the Sub250 1S 530mah LiPo here: https://oscarliang.com/product-ks7h
- Purchase the GNB 1S 550mAh here: https://s.click.aliexpress.com/e/_De4lTst
Powerful Brushless Motors
The Whoopfly16 comes with 1002 21000KV brushless motors, which are larger than the 0802 motors commonly used in Tiny Whoops. These powerful motors were even capable of carrying a small action camera, like the Insta360 Go or Runcam Thumb, though the extra weight makes it fly poorly.
User-friendly Design
The Whoopfly16’s design includes a small hole in the canopy for easy access to the button on the Walksnail VTX used for binding (linking) the goggles and VTX. However, to update VTX firmware, the drone must be disassembled to plug in the cable, which fortunately are not needed very often. In fact I managed to bind it to the FPV goggles without updating it.
Flight Cotnroller and Receiver
To access the electronics, remove the bottom piece (battery holder) secured by four screws. This design simplifies repairs and maintenance.
The flight controller comes preloaded with Betaflight 4.4 and has a built-in ExpressLRS receiver. The receiver antenna is just a simple wire. The solder quality appears decent.
It is slightly disappointing that the drone uses an ELRS SPI receiver, which will not be supported in the future. The flight controller features 16MB of flash memory for Blackbox logging, which makes tuning easier. It also has a current sensor, but the scale value is incorrect. By adjusting the scale to 150-160, the current reading makes more sense.
Flight Performance
The Whoopfly16 offers a smooth and locked-in flight experience thanks to its well-tuned PID out of the box. Although it’s almost 3 grams heavier than its counterpart, the BetaFPV Meteor75 (review), it still provides decent control and speed for enjoyable indoor flying. The higher KV motors in the Whoopfly16 effectively offset the extra weight, but at the cost of reduced efficiency and shorter flight times.
Despite its heavier weight, there isn’t a significant difference in flight performance, control, and power compared to the BetaFPV Meteor75. However, flight times are reduced by about 30 seconds. Indoors, pilots can expect just under 3 minutes of flight time.
Left: Meteor75; Right: Whoopfly16
The Whoopfly16 performs impressively both indoors and outdoors. While not designed for racing or freestyle due to its weight, it’s ideal for close proximity flying and is perfect for beginners looking to improve their indoor flying skills.
The drone maintains voltage throughout most of the flight, but pilots should be aware of the voltage drop towards the end of the battery’s charge. As a “feature” of the Walksnail 1S VTX, video cuts out when voltage drops below 3.1V. To avoid flying bind, set a low voltage alarm at 3.3V and land at 3.2V.
Test flight video:
How to Setup
The Whoopfly16 comes with Betaflight 4.4.0 pre-loaded, and the FC board target is GEPRCF411SX1280. The stock CLI diff can be found here. Here’s the provided manual:
To set up the Whoopfly16 for its first flight, follow these steps:
- Calibrate the accelerometer on a level surface to minimize drifting in Angle mode.
- Bind the ExpressLRS receiver to the radio by entering your binding phrase in the Betaflight Configurator Receiver tab. It’s compatible with ELRS 3.0 out of the box.
- In the Modes tab, set the Arm switch and enable turtle mode (flip over after crash).
- In the OSD tab, enable RSSI_dBm and LQ, and set the video format to HD.
- In the Configuration tab, set DShot Beacon (enable RX_SET only).
- Disable “Core Temp” warning in the OSD tab warning section. It’s a false warning which you can ignore.
Final Thoughts
The Sub250 Whoopfly16 offers an enjoyable flying experience for both indoor and outdoor environments, thanks to its solid construction, durable frame, HD camera options, and well-tuned PID. However, some users may find the heavy weight to be a major downside, and the need to take the drone apart for VTX firmware updates might be slightly annoying. While the Whoopfly16 isn’t designed for aggressive flying or performing inverted acrobatic tricks, it’s an ideal choice for beginners looking to improve and develop their indoor flying skills.
5 comments
Hi Oscar,
I received my WhoopFly16 Walksnail CRSF version yesterday and immediately updated the BF version without doing a save of the cli settings…. thankfully I found your cli diff file and was able to recover most of the original settings.
There was a couple of items from the different file that were not formatted correctly so still sorting them out, any chance you will be updating tp BF 4.4.2 and redo the diff file?
Thanks for all your great work.
Pete
I bought the hdzero whoopfly16 elrs as my first fpv and I’m unable to make it work. is it really “bind n fly”? When I connect the battery should it goes into wifi mode by itself? Does it require me to wait more than a minute for wifi mode? Should I see a yellow led flashing as the elrs status? Should the reconnect 3 times trick put it in binding mode? On mine there’s only green and red leds on the fc with blue and reds leds on the vtx. The video transmission work fine but I’m unable to put it in bind mode or wifi mode. Can you help?
Thank you
it doesn’t have WiFi. bind it by either enter bind phrase in Receiver tab in Betaflight or put it in bind mode by plugging / unplugging battery 3 times.
The USB connection on the Walksnail VTX isn’t just for firmware updates, you also need to use it to access video recordings from the on-board DVR. These recordings will have better video quality than recordings from the goggles DVR so having that on-board DVR is a nice bonus of the Walksnail system, especially for micro drones that are too small to carry an external action camera. Consequently having a frame/cover design that requires you to take the drone apart to plug the VTX in may be a significant annoyance for some owners, and it’s hard to understand why Sub250 did this. I can only assume they decided to make a Walksnail version late in the product development process, and it was too late to add an access hole for the USB connector.
This issue, and the SPI ELRS receiver, make me wish for a version 2 of this drone that has better VTX access and a UART RX.
There is an access hole but it is too small to fit the connector through, initially I plan on enlarging the hole enough for the connector to pass through more easily.