Quick Answer
The Flywoo Explorer LR 4 is a 4-inch sub-250g long-range micro FPV drone that comes in at least five video system variants: DJI O3, O4, O4 Pro, O4 Wide, and Walksnail Avatar. The bare airframe weighs 154g. With a 4S 750mAh LiPo, takeoff weight sits around 246g. For most UK pilots, we would buy the O4 Pro BNF if you have DJI Goggles 3 or N3, or the PNP kit to drop in whichever air unit you already own.
Why the Explorer LR 4 Exists (And Why We Stock It)
Sub-250g matters in the UK, but less than it used to. Since January 2026, the CAA lowered the registration threshold to 100g. A camera-equipped drone like the Explorer LR 4 now needs both an Operator ID and a Flyer ID regardless. The sub-250g weight still matters for where you can fly, keeping you in the A1 category with fewer restrictions. Flywoo's own spec sheet lists 154g for the bare O4 version, and with a 4S 750mAh LiPo pack, the whole quad lands at roughly 246g. That is not a coincidence. The frame, motor choice, and stack were all engineered around that number.
The result is a 4-inch toothpick that cruises. The Nin V2 1404 2750KV motors swing Gemfan 4024-2 props efficiently, and paired with the GOKU F722 Mini stack, you get GPS rescue, Betaflight 4.5, and a flight controller that handles 2-4S natively. For pilots who want to cover ground rather than throw tricks, this is one of the best-value sub-250g platforms available.
The Lineup Problem: Five Versions, Same Frame
Flywoo sells the Explorer LR 4 with five different video systems bolted to the same airframe. Here is what each one means:
| Variant | Video System | Resolution | Best For |
|---|---|---|---|
| O3 | DJI O3 Air Unit | 4K/120fps | Existing DJI ecosystem pilots |
| O4 | DJI O4 Air Unit | 4K/60fps | Budget DJI digital |
| O4 Pro | DJI O4 Air Unit Pro | 4K/120fps | Best image quality |
| O4 Wide | DJI O4 Wide | 4K/60fps, 159° FOV | Immersive cruising |
| Walksnail | Walksnail Avatar | 1080p/120fps | Walksnail goggle owners |
We stock the Explorer LR 4 PNP (without O3 Air Unit) at £199.99, which is the smart buy if you already own a DJI O3, O4, or O4 Pro air unit from a previous build. You get the complete airframe, GOKU stack, motors, GPS, and ELRS receiver, minus the video transmitter and camera. Drop in whatever you have.
Flight Time and Battery Strategy
This is where the Explorer LR 4 earns its "LR" badge. With a standard 4S LiPo, you get 5-8 minutes of sport flying. But the real magic happens when you switch to Flywoo's 18650 Lion pack. The Explorer Lion Pack (4S1P 3000mAh Sony VTC6) pushes flight time to 25-30 minutes of gentle cruising. The trade-off is discharge rate: Li-Ion cells sag harder under aggressive throttle, so reserve them for distance flying, not punch-outs.
For sport flying, we would pair the quad with 4S 900mAh HV LiPo packs. The 80C discharge handles throttle bursts without voltage sag, and the weight stays within the sub-250g budget.
GPS and the GOKU GM10 Mini V3
The Explorer LR 4 ships with Flywoo's GOKU GM10 Mini V3 GPS module, a 4.7g unit using the M10050 tenth-generation GNSS chip. It supports GPS, GLONASS, Galileo, BeiDou, QZSS, and SBAS, with 72 searching channels and a 10Hz update rate. In practice, it locks 25-30 satellites in under three minutes. For a sub-250g cruiser, having reliable GPS rescue is not optional. If you lose video or control link over open terrain, Betaflight's GPS Rescue mode will bring the quad home using coordinates from this module.
What We Would Actually Buy
For UK pilots entering the long-range micro space, the Explorer LR 4 PNP is the best value route. You are not paying for a video system you might already own. If you are starting fresh with DJI goggles, the O4 Pro BNF gives you the best image quality with Race Mode low latency. If you fly Walksnail, the Walksnail variant gives you 22ms latency at 1080p/120fps without the DJI tax. The Explorer LR 4 sits alongside other toothpick-class micro drones in our range, but none of the others match its sub-250g weight compliance with a 4S LiPo.
What we would avoid: the O4 Wide if you care about image sharpness. The 159° field of view creates a strong fisheye effect that some pilots love for cruising immersion but makes footage harder to stabilise. Use Gyroflow, not RockSteady, on any Explorer LR 4 O4 variant. Flywoo explicitly warns that RockSteady causes abnormal shaking due to vibration feedback overload from the O4's sensitive gyroscope.
FAQ
Is the Explorer LR 4 really under 250g with a battery?
Yes. The bare O4 airframe weighs 154g. With a 4S 750mAh LiPo, total takeoff weight is approximately 246g. You stay under the 250g CAA threshold, but the margin is tight. Adding an O4 Pro air unit (heavier than O4) or a larger battery may push you over.
What is the practical range?
Flywoo claims 20km under FCC rules. In the UK, CE mode limits the DJI O4 to 25mW on 5.8GHz, which realistically gives 1-3km. Pilots who enable the higher 100mW 5.2GHz Auto mode report 3-5km in clear conditions. We cover this in our long-range FPV build guide.
Do I need to register this drone in the UK?
Yes. Since January 2026, the CAA threshold dropped from 250g to 100g. Any camera drone over 100g now requires both an Operator ID (around £12.34 per year) and a Flyer ID. The Explorer LR 4 at 154g bare or ~246g with battery is well above the threshold. See our UK drone laws guide for the full breakdown.
Can I fly the Explorer LR 4 indoors?
Technically yes, but it is not designed for it. The 4-inch props and open-frame design make it louder and more dangerous indoors than a 65-75mm whoop. For indoor flying, look at our BetaFPV Air75 II guide instead.
What radio do I need?
Any ELRS 2.4GHz transmitter. The Explorer LR 4 ships with an ELRS receiver by default. We recommend a RadioMaster Pocket or Boxer for this class of drone. See our sub-250g weight budget guide for receiver weight considerations.