If you’ve ever gone hiking with your FPV drone, you know that weight and bulk are crucial factors when it comes to fitting everything into a backpack. DarwinFPV offers a compact 4-inch FPV drone, the FoldApe, that can be folded into an even smaller form factor! In this review, we will explore its features, build quality, and overall performance.
Interested in long range flying? Check out my guide: https://oscarliang.com/long-range-fpv-flying-mini-quad/
Where to Buy?
Get the DarwinFPV FoldApe from these vendors:
The FoldApe is available in DJI O3 version, Runcam Wasp/Link, and Walksnail; I’m testing the analog version.
The drone comes with these accessories, including extra screws, antenna posts, and zip ties.
Specifications
- FC/ESC: DarwinFPV F411 15A ELRS AIO Board
- Receiver: Onboard SPI ELRS 2.4GHz
- GPS: DarwinFPV GM8
- Motor: 1504 3800KV
- Props: Gemfan F4019-2
- FPV Camera: Caddx Ant
- VTX: DarwinFPV 600mW
- Wheelbase: 168mm
- Arm thickness: 4mm
- Battery Connector: XT30
- Recommended Battery: 3S 1150mAh LiPo or 3S 3000mAh Li-ion
- Weight without Battery: 127.8g
Closer Look
Upon unboxing, the FoldApe4’s compactness was immediately striking. It’s fascinating how such a small package can equip everything necessary for long-range flights.
Compared to the Flywoo Explorer, the size difference is significant.
Folding Mechanism
The most striking feature of the FoldApe4 is, undoubtedly, its folding mechanism. This design choice is not just about aesthetics; it’s about practicality, making the drone compact and easy to transport. This approach is further complemented by foldable props, allowing it to shrink down to a remarkably compact size.
Folding and unfolding the drone is straightforward, thanks to the intuitive design and secure locking mechanism. To unfold it, you pull the arms out and attach two screws in the middle of the bottom plate. When folded, those two screws can go back in those holes so you don’t lose them.
If you don’t like the folding aspect at all, you can just leave those screws in permanently, and it behaves just like a regular 4-inch drone, making the folding optional.
The interlocking arms, 4 mm thick, have a staggered configuration. Note that the rear arms are lower than the front arms and they are not on the same plane. When unfolded, the arms are stiff and have no play thanks to tight tolerance, ensuring optimal flight performance.
Electronics
Unlike 5-inch freestyle quads, which are normally designed primarily for raw power, the FoldApe4 leans towards efficiency and weight optimization.
It’s designed to run on a 3S battery with an XT30 connector. The FC has a built-in SPI ELRS receiver, and it comes with a GPS module. On paper, it sounds like a fantastic setup for long-range flying; however, during my testing, I realized it has some serious limitations as explained shortly.
Sub250 Weight Limit
With a 3S 3000mAh Li-ion battery (typically weighing around 160g), the overall weight is going to be over 250 grams – at around 285g. If you want to stay under the 250g limit, you would have to consider using a 3S LiPo.
Flight Time and Performance
I have very few 3S batteries, so I tested the FoldApe with a 3S 550mAh LiPo – the largest 3S I have. DarwinFPV recommends using larger LiPo batteries to achieve longer flight times, such as a 3S 1150mAh LiPo or a 3S 3000mAh Li-ion.
Regardless I still achieved over 5 minutes of flight time using a 3S 550mAh, which is impressive, but I doubt we can reach the advertised 20 minutes with 3S 1150mAh. This could be because I was flying aggressively; perhaps more conservative flying could allow longer flight time.
The flight performance was exceptional. I wasn’t expecting such a nimble and responsive drone. It flew almost like a toothpick drone, it was very quiet and efficient too! While it may not be the fastest quad I’ve flown, it certainly offers a lot of fun!
As usual, DarwinFPV has managed to build a well-performing drone from budget components, and they have put significant effort into tuning them. Very well done.
Limitations and Considerations
I enjoy flying the DarwinFPV FoldApe, but it leaves something to be desired in terms of long-range capabilities.
The GPS is essentially useless, likely the same module used in the Darwin129 7-inch. I never achieved a GPS lock; it didn’t even detect a single satellite during my hours of testing! Consequently, I couldn’t test the GPS rescue feature.
With the analog setup, I started experiencing pretty bad signal just 500 meters away—hardly inspiring confidence for long-range flights. I’m not entirely sure if the VTX or the antenna is to blame, but with 600mW, I’d expect at least a couple of kilometers or range without much breakup in line of sight. You can estimate FPV range using this calculator: https://oscarliang.com/js/fpvrange.html
The ExpressLRS receiver is a SPI receiver built into the flight controller, equipped with a simple monopole antenna, which isn’t ideal for long-range flights either.
The absence of a buzzer, an accessory that is crucial for long-range flights, is notable.
I also wish this quad supported 4S batteries instead of 3S. Not only are 4S batteries more popular, providing a wider availability, but the increase in voltage also means lower current for the same power, making the quad more efficient, especially considering the thin wires used in this quad.
In the future, with long range in mind, I plan to make the following improvements to my FoldApe:
Unfortunately, the FC/ESC AIO board only supports up to 3S, so you can’t swap out those motors for 4S without upgrading the AIO FC as well. That’s gonna be expensive. So for now, I guess I’ll leave the FC and motors as they are.
How to Setup
The setup process was straightforward, requiring only a couple of adjustments.
It came with Betaflight 4.4.2 firmware, target DARWINF4SX1280HD. The original CLI dump can be found here.
The ESC is already flashed with Bluejay firmware (S-H-50 – Bluejay BETA, 0.14, 48kHz), and it performed well during my tests.
First, you need to bind the receiver to your radio by entering your bind phrase in the “Receiver” tab in Betaflight.
Then, set up modes (arm switch) and finally set up OSD (NTSC camera).
Final Thoughts
Designing a large drone, such as a 7-inch or 8-inch (like the Speedybee Mario 8) to be foldable, makes sense, but a 4-inch drone is already quite compact. It seems a bit unnecessary to fold it into something even smaller unless you’re looking to fit it into your pocket. Additionally, with a folding mechanism, more joints and parts are involved, increasing the likelihood of failure and complications of repairs and maintenance.
However, if you’re limited on space to even pack a full size 4-inch FPV drone, the FoldApe4 presents a compelling option. It offers a unique blend of portability, performance, and price, making it a standout choice in the 4-inch long-range FPV drone category.
While it may not feature top notch components, its thoughtful design, solid construction, and flight performance create a compelling package for pilots of all skill levels.
There’s certainly room for customization and improvement, but I absolutely love how this drone flies—smooth, responsive, and quiet. Perhaps a little disappointing in terms of long-range capabilities, but for something priced at only $180, it’s a remarkable value.
Get the DarwinFPV FoldApe from these vendors:
