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 all drone, it’s not good. There are a variety of mods and upgrades that may considerably enhance efficiency—similar to putting in a range receiver, optimizing antenna and GPS mounting, decreasing weight, and a customized PID/filter tune.
Try my full assessment of the Flywoo Explorer O4 Professional: https://oscarliang.com/flywoo-explorer-lr4-o4-pro/
Variety Receiver Improve & Antenna Mounting
The inventory receiver makes use of a single antenna mounted horizontally on the entrance underneath the body. Whereas that is nice for short-range flights, it’s removed from ideally suited for long-range flying.
By upgrading to a real range receiver with two antennas, you possibly can mount them vertically on either side of the body. This setup ensures that at the least 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 possibly can 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 range receiver, together with the additional antenna, provides about 3g in comparison with the inventory RX. Nonetheless, for the advance in sign reliability, I feel it’s effectively price 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 at the least 8 satellites for dependable GPS Rescue). Additionally, I hardly ever noticed greater than 20 satellites, and I think it’s on account of Flywoo’s option to mount the GPS underneath the VTX antennas, which introduces vital interference.
My answer? Transfer the GPS to the entrance of the drone.
In earlier Explorer variations, this wasn’t an possibility as a result of I needed to mount a Bare GoPro up entrance. However due to the DJI O4 Professional’s onboard recording, I 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 may as well safely take away the copper tape from the GPS module to save lots of a bit extra weight.
The advance is substantial. After relocating the GPS:
- 3D repair (8 sats) in underneath 1 minute from a chilly begin
- Nearly instantaneous repair between battery swaps
- Most satellite tv for pc rely elevated to 29
Switching GPS and Receiver UARTs
This mod is elective—however price contemplating when 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.
Vital: The connector pinouts for UART2 and UART5 are totally different (why, Flywoo?!). You’ll must re-pin the wires within the connectors. It’s just a little annoying however not troublesome.
Weight Discount
I’ve optimized weight on dozens of BNF drones, and the Explorer was truly one of the crucial difficult – it’s already fairly effectively optimized, so there will not be many locations you possibly can scale back weight. Additionally it’s similar to light-weight drone, saving a number of grams may really feel underwhelming. However when 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 a substitute of metallic on the FC/ESC stack
- Changed screws (elective):
- 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 in a position to shave 9g off my construct. Nonetheless, as a result of I upgraded to a range 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 may most likely eliminate one other 10g or extra. Nonetheless there’s presently no such “Bare O4 Professional” conversion package exists (like what Flywoo did with the Bare O3 package), however hopefully, some producers would launch one sooner or later.
You might think about eradicating the warmth shrink on the battery for a ~2g saving. However it’s not advisable when you plan to journey by planes—batteries with out labels won’t go 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 underneath 250g, the heaviest battery you need to use is round 80g. The most important 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 can be the best choice, 30+ minutes of flight time and 20km+ flight distance are doable. 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 may as well purchase pre-built Li-ion packs, however they usually use cheaper cells, right here’s an inventory 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 disenchanted Flywoo didn’t even attempt to optimize the filters. Meaning 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 doable.
In 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
Wish 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 inexpensive choices obtainable: https://oscarliang.com/betafpv-nd-filters-dji-o4-pro/
Discover ways 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 scale back CPU load)
- Enhance 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 possibly can take the already glorious Flywoo Explorer LR4 O4 and push it to the following degree—bettering sign reliability, GPS efficiency, flight efficiency and effectivity, all whereas staying underneath 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!
