The Flywoo Explorer LR4 is arguably probably the greatest sub250 long-range FPV drones in 2025 when paired with the DJI O4 Professional Air Unit. However like several drone, it’s not excellent. There are a selection of mods and upgrades that may considerably enhance efficiency—similar to putting in a variety receiver, optimizing antenna and GPS mounting, decreasing weight, and a customized PID/filter tune.
Take a look at my full assessment of the Flywoo Explorer O4 Professional: https://oscarliang.com/flywoo-explorer-lr4-o4-pro/
Range Receiver Improve & Antenna Mounting
The inventory receiver makes use of a single antenna mounted horizontally on the entrance beneath the body. Whereas that is effective for short-range flights, it’s removed from ultimate for long-range flying.
By upgrading to a real variety receiver with two antennas, you’ll be able to mount them vertically on each side of the body. This setup ensures that no less than one antenna is in line of sight together with your transmitter more often than not, leading to a much more constant and dependable radio hyperlink.
I’m utilizing the RadioMaster RP4TD receiver, get it right here:
It’s a bit too huge to mount contained in the body, so I hooked up it beneath utilizing a tiny 3D-printed TPU strap – I made it free to obtain right here: https://www.thingiverse.com/factor:7062885
I additionally designed an antenna holder you’ll be able to mount on the standoffs, it has a small 10-degree tilt so it stays vertical when cruising ahead. I made the STL file free to obtain right here: https://www.thingiverse.com/factor:7062886
This variety receiver, together with the additional antenna, provides about 3g in comparison with the inventory RX. Nonetheless, for the development in sign reliability, I feel it’s effectively value it. If you happen to don’t fly lengthy vary or are proud of the inventory efficiency, the unique receiver remains to be completely usable.
Optimizing GPS Mounting
Out of the field, the Explorer LR4 takes a very long time to get a GPS 3D repair (Betaflight recommends no less than 8 satellites for dependable GPS Rescue). Additionally, I hardly ever noticed greater than 20 satellites, and I believe it’s as a consequence of Flywoo’s option to mount the GPS beneath the VTX antennas, which introduces vital interference.
My resolution? Transfer the GPS to the entrance of the drone.
In earlier Explorer variations, this wasn’t an choice as a result of I needed to mount a Bare GoPro up entrance. However due to the DJI O4 Professional’s onboard recording, I now not want a separate digicam, releasing up the proper spot for GPS.
I designed a customized front-mounted GPS holder, free to obtain right here: https://www.thingiverse.com/factor:7062882/
You too can safely take away the copper tape from the GPS module to avoid wasting a bit extra weight.
The development is substantial. After relocating the GPS:
- 3D repair (8 sats) in beneath 1 minute from a chilly begin
- Virtually prompt repair between battery swaps
- Most satellite tv for pc depend elevated to 29
Switching GPS and Receiver UARTs
This mod is non-compulsory—however value contemplating in case you’re mounting the GPS and receiver like I did above, as a result of the inventory cables aren’t lengthy sufficient. It makes extra sense to swap the UART ports (i.e., transfer the receiver to UART5 and the GPS to UART2). This additionally retains the wiring cleaner.
Necessary: The connector pinouts for UART2 and UART5 are totally different (why, Flywoo?!). You’ll must re-pin the wires within the connectors. It’s a bit annoying however not troublesome.
Weight Discount
I’ve optimized weight on dozens of BNF drones, and the Explorer was really one of the vital difficult – it’s already fairly effectively optimized, so there are usually not many locations you’ll be able to scale back weight. Additionally it’s similar to light-weight drone, saving a number of grams would possibly really feel underwhelming. However in case you really care about efficiency, a gram right here and there provides up.
Warning: Eradicating {hardware} reduces crash resistance. Proceed at your individual threat.
Right here’s what I did:
- Eliminated arm guards and solely use two screws per motor
- Eliminated the entrance second-row standoffs
- Eliminated copper tape on GPS wires (provided that it’s relocated to the entrance like I did)
- Minimized fabric tape used on motor wires
- Used plastic nuts as an alternative of metallic on the FC/ESC stack
- Changed screws (non-compulsory):
- Prime/backside plates: 5mm (was 6mm)
- Stack: 16mm (was 20mm)
- Motors: 5mm (was 6mm)
- Props: 6.5mm (was 7mm)
After performing all these modifications, I used to be capable of shave 9g off my construct. Nonetheless, as a result of I upgraded to a variety antenna, it added 3g again. It won’t sound a lot, however that’s 5% weight discount on a quad that’s already extraordinarily light-weight, and might probably translate to a different 20 to 30 seconds extra flight time.
I feel the DJI O4 Professional air unit has an enormous potential for weight saving too. If we take away the case, heatsink and use lighter antenna options, we might in all probability eliminate one other 10g or extra. Nonetheless there’s at present no such “Bare O4 Professional” conversion equipment exists (like what Flywoo did with the Bare O3 equipment), however hopefully, some producers would launch one sooner or later.
You can contemplate eradicating the warmth shrink on the battery for a ~2g saving. However it’s not really useful in case you plan to journey by planes—batteries with out labels won’t move safety. Additionally, you possibly can shorten motor wires which could save one other 2–3g, however I didn’t do it this time.
Because it stands, if you wish to keep beneath 250g, the heaviest battery you need to use is round 80g. The largest battery I can discover is the GNB 4S 850mAh LiHV 60C weighs in at ~73g. Get the it from AliExpress: https://s.click on.aliexpress.com/e/_olJ1Gke
If you wish to get the longest flight time, and weight isn’t a difficulty, 4S 18650 battery could be the best choice, 30+ minutes of flight time and 20km+ flight distance are potential. Ideally, it is best to construct your individual pack utilizing high-quality cells. I like to recommend the Molicel P30B 18650 cells, which I’ve examined right here: https://oscarliang.com/best-18650-li-ion-battery/#Outcomes-and-Suggestions. You too can purchase pre-built Li-ion packs, however they usually use cheaper cells, right here’s a listing of choices: https://oscarliang.com/li-ion-battery-long-range/#Shopping for-Prepared-Made-Li-ion-Battery-Packs
PID & Filter Tuning
The Explorer flies decently out of the field—however I’m upset Flywoo didn’t even attempt to optimize the filters. Which means there’s nonetheless room for enchancment, particularly after all of the {hardware} modifications we’ve made. Fortunately, the Explorer has onboard flash for Blackbox logging, which makes filter tuning potential.
To your reference, I’ve shared my customized PID and filter tune on Patreon, together with GPS Rescue config, ports, energy settings, charges, OSD format, and extra: https://www.patreon.com/posts/flywoo-explorer-131255399
Need to tune it your self? Begin right here:
Utilizing ND Filters
Get extra cinematic footage by utilizing ND filters. The official DJI ND filters don’t match within the Flywoo Explorer LR4 body, so I like to recommend low-profile ND filters similar to those from BetaFPV—they’re additionally among the many most reasonably priced choices accessible: https://oscarliang.com/betafpv-nd-filters-dji-o4-pro/
Learn to use ND filters on this information: https://oscarliang.com/nd-filter-fpv/
Different Minor Tweaks
- Disable LED_Strip in Betaflight’s Configuration tab (to cut back CPU load)
- Improve PID Loop Frequency from 2KHz to 4KHz (there’s sufficient CPU headroom)
- ESC Protocol: DShot300
- Present Sensor Scale: 450
- Voltage Sensor Scale: 111
Conclusion
With only a few considerate upgrades and modifications, you’ll be able to take the already wonderful Flywoo Explorer LR4 O4 and push it to the following degree—bettering sign reliability, GPS efficiency, flight efficiency and effectivity, all whereas staying beneath 250g.
In case you are nonetheless debating whether or not to get the Explorer, try my assessment right here: https://oscarliang.com/flywoo-explorer-lr4-o4-pro/
Let me know what mods you’ve tried—or if there’s something I missed!
