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/
Table of Contents
Where to Buy?
Get the DarwinFPV FoldApe from these vendors:
- DarwinFPV: https://oscarliang.com/product-pvmu
- AliExpress: https://s.click.aliexpress.com/e/_DFQm7Ez
- Banggood: https://oscarliang.com/product-rvkd
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 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.
Battery I was using: https://oscarliang.com/product-m4n8
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 of range without significant 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:
- Install a proper M10 GPS module, good options here: https://oscarliang.com/gps-review/
- Update to the latest Betaflight 4.5 for the most up-to-date GPS Rescue feature, update guide: https://oscarliang.com/betaflight-4-5/#How-to-Update-to-Betaflight-45
- Install an external ExpressLRS receiver, good options here: https://oscarliang.com/setup-expresslrs-2-4ghz/#Receivers
- Change the antenna to a better one and see if it performs better, good options here: https://oscarliang.com/best-fpv-antenna/#Omni-Antennas-Top-Of-The-Line
- Install a self-powered buzzer: https://oscarliang.com/best-5-inch-fpv-drone-parts/#Beeper
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:
- DarwinFPV: https://oscarliang.com/product-pvmu
- AliExpress: https://s.click.aliexpress.com/e/_DFQm7Ez
- Banggood: https://oscarliang.com/product-rvkd
23 comments
Didn’t want for my message be lost under Michael’s thread, but it could be reply to it as well.
Received my foldape4 this week and was simply testing it at home when suddenly after only 5th arm or so, one of the props just fell out from the motor…
Sorry for caps, but’s it’s really crucial…EVERY SINGLE PROP FIXING PLATE WAS PLACED UPSIDE DOWN on my drone FROM THE FACTORY!!!
Yes, they’re not symmetrical – there are indentations for screwheads on the top.
1) screws seem 1-2mm too short when it happens – there’s only ~1mm of free tread left
2) you cannot tighten them up because fans stop turning freely due to this metal insert being pressed by this plate
After fixing it no more troubles seen yet…except issues with GPS mentioned here…and yes, soldered CRSF to it
As for the longevity…well…I used 4000mAh 21700 3s battery that makes total of 363g with the drone…and simply was too bored hanging in the middle of the room for 20min and after disarm OSD displayed 10.2V (starting from 12V) Plus wind and human factor – yet to be tested. Overall, really smooth thing.
Can anyone point me at where I can find matching props for this bird? My right rear prop had a sudden unscheduled disassembly event mid air and the pieces of the prop disappeared in all directions. I found some “F4019-2” on Ali Express, but when they arrived, the prop size and shape is a good match, but the central bar system is quite different. It has both a top and bottom plate the sandwich the pop blades, and no screws. So, I guess it would just pressure fit on, which doesn’t seem very secure.
Alternatively, I’m not that committed to the folding aspect of this drone, so if anyone can recommend some alternative props that would be great too. Something that favours quiet, efficient flight would be ideal….
Spare props can be found on Darwin’s website: https://darwinfpv.com/products/darwinfpv-f4019-2-folding-propeller?ref=oscarliang
Oooh, that seems to be a new addition! Thanks Oscar!
From their page: “The DarwinFPV F4019-2 folding propeller is an upgrade based on the Gemfan Floppy Proppy 4019-2 propeller. We abandoned GEMFAN’s original plastic propeller clamp and used a high-precision stainless steel bushing with a carbon fiber propeller clamp to control the accuracy to ±0.05mm. It vibrates less, is lighter, and is more resistant to explosions than the original propeller.”
It would have been nice to know that what they call a “Gemfan F4019-2” prop actually is not that at all, before I went and ordered a whole bunch of spares. Oh well.
You can still use those blades – they just replaced the center part I believe? So it’s not all a waste.
Oh, okay. I assumed that because the original gemfans are pressure-fit, that they wouldn’t work on foldape motors that are using screws? I haven’t used a pressure-fit prop on anything since brushed miro-drones. How much pressure is okay to use to force a prop onto the motor shaft? I had a quick go at pushing the gemfans on, but wasn’t sure how much force should be required and didn’t want to break anything….
Regarding your plans: Is it possible to connect an receiver instead of the internal one? Does it have a free UART?
How will you add an external ELRS Rx? Does the board have a free UART Port?
Yes, one UART for external RX, one UART for GPS, and you can setup soft serial for Smart Audio.
Thank you for your review and support.
How will you add an external ELRS Rx? Does the board support that?
The price is seems pretty compelling. It seems like the main downsides are:
1) the folding mechanism adds to the complexity and cost, while reducing the robustness
2) The GPS isn’t very good
3) It uses less-common 3 cell batteries
4) The VTX maybe isn’t too good
Any recommendations for which other drones to check out that might be better overall in the low-cost 250g long-range segment?
Nothing really comes close to the Darmwin in terms of value, but performance and quality wise, the Flywoo Explorer still reigns (the Analog and Vista versions).
I am still waiting for mine, been seeing some mixed reviews on weather you actually need to use the 2 screws when unfolded or not….does anyone know?
It has a really tight tolerance, the arms stay in position quite well without the screws due to friction between the arms and the top/bottom plates. But personally I wouldn’t trust only friction, if the arms fold during flight it might crash. Install those screws when flying for max safety, it’s only 2 screws anyway.
The extra F4019-2 propellers are quite a mess.
Original joining plate between the 2 blades has “a hole for the screw head” and in photos here it even seems deeper than on mine. The extra propellers are same 2 blades without the metal insert to wrap around m2, that’s easy to press it in, but the extra joining plates don’t have the “hole for the screw” and the provided screws are thus too short.
There is around 10 slightly longer m2 screws in the screws packs that fit just right, but I should get more before I crash.
The extra joining plates also have a small notch from where it was broken of some form, that can be sanded down. But to make a “a hole for the screw” requires some extra tools and nerves I don’t have.
Mine came with the plate for the props installed upside down and the screws kept coming out. Only realized after I removed the plate and the props simply to find the countersunk hole for the screw head was installed wrongly. Flip the plate around and now the screws can go deeper as it should be into the prop holder.
Overall love how quiet this bird is and it flies like a toothpick quad – amazing. I can fly it almost anywhere without bothering anyone. Love it.
Thank you for the review! Does anybody know the name of the tape (presented at the pictures), the motor cables were fixed to the arms? I tried to find it in some webshops, but unfortunately unsuccessful.
Thanks in advance!
It’s called cloth tape, check out my supplies and tools page: https://oscarliang.com/fpv-tools/#Clothes-Tape
If it’s the same as emax tape it’s, specifically acetate cloth tape. I don’t like the fabric cloth tapes they’re not as strong, get dirty and are not really waterproof, not to mention they don’t look as nice.
It’s the same sort of things just depends on the quality and where you get it from.
I accidentally connected a 4S battery to that DarwinFPV F411 15A ELRS AIO board and flew my 2″ drone for a few minutes. Nothing bad happened. I didn’t even notice I was using the 4S. Let’s say this FC is compatible with 4S
Guess the Motors wont like it though. :/