Evaluate: Flywoo Explorer LR4 with DJI O4 Professional – The Final Sub-250g Lengthy-Vary FPV Drone

I’ve been flying the Flywoo Explorer LR4 for five years, and it stays one in every of my favourite drones to take when touring. It’s light-weight and affords distinctive flight time—excellent for long-range exploration and capturing cinematic footage. So after I heard Flywoo had launched a brand new model that includes the DJI O4 Professional, I knew I had to purchase one and take a look at it out. On this evaluation, I’ll share my ideas on the up to date Explorer LR4, its execs and cons, and how one can optimize its flight efficiency and reliability.

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Study extra about long-range FPV flying on this information: https://oscarliang.com/long-range-fpv-flying-mini-quad/

Just a few years in the past I travelled overseas with the Explorer carrying the Vista + Bare GoPro 6 on this compact setup.

And it was in a position to produce this degree of footage, very spectacular efficiency. The O4 Professional is simply going to get even higher!

The place to Purchase

You should buy the Explorer LR4 O4 Professional Version from these distributors:

Be aware: You should buy the Explorer LR4 with or with out the DJI O4 Professional Air Unit. Nevertheless, the model that features the O4 Professional is $270 extra—whereas the O4 Professional alone prices solely $220. That’s a $50 markup! If you happen to’re comfy putting in the Air Unit your self, it’s less expensive to purchase the drone with out it and set up the O4 Professional individually. I’ll stroll you thru the set up course of later on this evaluation.

Equipment embrace:

8 × Gemfan 4024-2 Black Props
2 × Battery Straps (15x180mm)
Screws
Extra 3D printed mounts

Specs

Body: Flywoo Explorer LR4 O4 PRO Body Equipment
Flight Controller: Goku F722 Mini
ESC: Flywoo 45A 32bit 4-in-1 ESC
FPV System: DJI O4 Professional Air Unit
Receiver: ExpressLRS
Propellers: Gemfan 4024×2 Bi-blade
Motors: Flywoo Nin V2 1404 2750KV
GPS: GOKU GM10 Mini V3
Battery Connector: XT30
Weight:
- 171g (with out battery)
- 239g with a 4S 720mAh LiHV (sub-250g)
- 266g with a BetaFPV Lava 4S 850mAh LiPo

Construct High quality & Design

Nearly the Identical because the Unique Design

Flywoo hasn’t modified a lot concerning the Explorer’s design for the reason that unique model from 5 years in the past. The principle replace is a modification to the body to accommodate the DJI O4 Professional Air Unit.

Flywoo Explorer Lr4 With Dji O4 Pro Long Range Sub250 Fpv Drone Compare Original Version

Left: Explorer O4 Professional; Proper: Unique Explorer with Caddx Vista

For these unfamiliar with the Explorer, it makes use of a deadcat structure, which helps hold the props out of the digicam’s view. The arms are extraordinarily skinny—this drone isn’t constructed for crashing, however reasonably for staying mild to maximise effectivity and flight time.

The soldering high quality appears nice. The motor wires are soldered vertically, protecting the profile low and decreasing the chance of wire harm. Antennas are mounted in a V-shape at 90°, which is perfect for sign reception—good consideration to element from Flywoo.

Electronics

Flywoo upgraded the FC/ESC stack from 16x16mm to 20x20mm. The bigger board measurement not solely makes repairs simpler doubtlessly, however the brand new ESC now options 45A 32-bit help—a significant step up from the earlier 13A model. It’s an enormous overkill for this construct (you’ll hardly use 10% of its present score), however hey, having further headroom is rarely a foul factor.

All of the elements are linked to the FC by way of connectors – no soldering on the FC in any respect.

The receiver will not be hooked up to something, simply left there hanging freely. With the O4 digicam put in it’s type of being pressed by all of the wires between the stack and digicam, so it’s not free or something and hasn’t been a priority up to now throughout my testing.

They’ve additionally lastly added a present sensor, which is a giant plus for long-range flying. Voltage alone might be unreliable—particularly with low C-rated batteries that undergo from voltage sag. With a present sensor, you get a significantly better concept of battery utilization and might higher choose when to land.

Because of the tight house, Flywoo needed to solder the capacitor on to the XT30 connector, which is a bit removed from the ESC. The capacitor can also be fairly small. Whereas not the simplest setup for noise filtering, it’s higher than nothing. Fortunately, the small motors don’t produce an excessive amount of electrical noise, so this ought to be nice most often. Study capacitor on this information: https://oscarliang.com/capacitors-mini-quad/

GPS Enhancements

Flywoo continues to mount the GPS module on the rear, just below the VTX antennas—a location that I’ve all the time discovered problematic. Within the earlier mannequin, the M8-based GPS would take a very long time to get a 3D repair, and satellite tv for pc counts have been typically low as a consequence of interference from the close by VTX antennas. The routing of GPS wires beneath the VTX added much more EMI and made matter worse.

This time round, Flywoo tried to handle the difficulty by:

Shielding the GPS wires with copper tape
Upgrading to a more recent, extra highly effective M10 GPS module

Whereas I nonetheless want that they had moved the GPS away from the VTX completely, these modifications ought to enhance GPS reliability.

Receiver Antenna Mounting

One other design alternative I’m not a fan of is how the receiver antenna is mounted.

Whereas this mounting technique is less complicated for producers and works nice for short-range flights (inside a few km), it’s not supreme for long-range. For finest efficiency, antennas ought to be mounted vertically. Study extra about antenna mounting: https://oscarliang.com/antenna-positioning/

DJI O4 Professional

The DJI O4 Professional Air Unit is securely mounted on standoffs, leaving clearance for wires beneath. This setup permits for first rate airflow, serving to to maintain the air unit cool throughout flight. Regardless that the O4 Professional digicam is simply mounted between easy TPU adapters, I didn’t discover any jello or vibration within the footage, Gyroflow additionally works flawlessly.

One draw back: the digicam tilt angle is extremely restricted, with a most of round 15 levels. This restricts how briskly you may fly, as greater speeds can have you staring on the floor extra. The restricted angle is as a result of body’s compact peak—the O4 Professional digicam is bodily giant, and growing the lean would require a taller body, which in flip would improve weight, drag and scale back effectivity. That stated, for a sluggish cruiser just like the Explorer, this angle is satisfactory.

Onboard Buzzer

Flywoo features a self-powered buzzer—a uncommon characteristic in BNF FPV drones. In case your battery dies or will get disconnected in a crash, the buzzer will proceed beeping for hours, drastically bettering your probabilities of discovering the drone.

If you happen to’ve by no means used one in every of these buzzers earlier than, don’t be stunned when it begins beeping after you unplug the battery—that is anticipated conduct. To cease the beeping, simply press and maintain the button on the buzzer for just a few seconds to disarm it. If you happen to’re merely swapping batteries, you don’t must press the button, merely plugging in a brand new battery will routinely cease the beep.

Flight Efficiency

Right here’s footage from one in every of my take a look at flights:

Battery Selection and Effectivity

Relying on battery weight, the Explorer pulls round 6-7A at 50 km/h and seven–8A at 60 km/h—which is impressively environment friendly.

If you wish to keep beneath the 250g weight restrict, the most important battery you need to use can be 4S 720mAh LiHV, which is available in just below the brink and affords round 8 minutes of cruising flight time. LiHV batteries are barely extra energy-dense than common LiPo, providing you with a bit extra flight time, see my testing right here: https://oscarliang.com/lihv-battery/

With some modifications—akin to eradicating pointless elements—you may be capable of run 4S 850mAh LiPo and nonetheless keep sub-250g. This might doubtlessly offer you over 10 minutes of flight time and as much as 7 km of complete flight distance.

For optimum flight time, the 4S 18650 Li-ion battery pack is the way in which to go. It may possibly present nearly half-hour of flight time (primarily based on my testing with the earlier model of Explorer), although it will increase the general weight to round 365g. Ideally, you need 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 typically use cheaper cells, right here’s a listing of really useful choices: https://oscarliang.com/li-ion-battery-long-range/#Shopping for-Prepared-Made-Li-ion-Battery-Packs

Personally, I like cruising at round 40–45% throttle (45–50 km/h) with 4S 850mAh, or 50% throttle (50–60 km/h) with the 4S Li-ion pack. This appears to be the optimum throttle vary for maximizing flight time.

Cinematic Smoothness

This drone flies prefer it was on rail, very locked in and steady. Within the flight footage, I used to be flying in 20 MPH gusts, and whereas the drone did drift fairly a bit (as a consequence of its mild weight), it didn’t wobble like many smaller micros do. That stability may be very helpful for capturing cinematic footage.

Freestyle Functionality

With hover at 36% throttle and a prime pace of 105 km/h utilizing a 4S 850mAh LiPo, the Explorer will not be a quick drone. Throughout excessive maneuvers, it tends to wobble and expertise instability as a result of restricted energy of the motors.

Let’s be trustworthy—the Explorer feels underpowered. The 1404 motors are thought-about very small for 4-inch props; they’re generally utilized in 2.5-inch freestyle drones, and in my expertise, they even wrestle with 3-inch props! However keep in mind, this drone is constructed for effectivity and endurance, not uncooked energy, so it is sensible.

Whereas it’s no freestyle beast, it might probably deal with fundamental strikes like split-S, energy loops, and inverted yaw spins simply nice. You simply want to regulate your expectations—this isn’t a 5-inch ripper.

Noise

The Explorer is surprisingly quiet. It’s not silent, however it’s a lot much less intimidating than a 5-inch freestyle FPV drone. This makes it well-suited for flying in parks or city areas with out drawing an excessive amount of consideration.

Sturdiness

As talked about earlier, Flywoo hasn’t modified a lot concerning the Explorer’s body design for the reason that unique model—and primarily based on my expertise, it’s fairly fragile. I’ve damaged arms in mild to medium crashes—not even arduous hits—as a consequence of how skinny the arms are. So long as you’re conscious of its fragility and stick with cruising as a substitute of aggressive flying, it’s nice.

GPS and Rescue Mode

Slight disappointment right here: the GPS takes fairly a very long time to get a repair from a chilly begin—about 6 minutes to amass 8 satellites. The max satellite tv for pc depend was round 19. I think the low GPS efficiency is because of its mounting location—it’s beneath the VTX antennas.

That stated, Betaflight GPS Rescue Mode works effectively. I’d nonetheless advocate just a few modifications to make it higher—akin to adapting “throttle fallback” (see my Rescue mode information for element) and decreasing return pace, and so forth.

How one can Setup

Putting in DJI O4 Professional

I purchased the Flywoo Explorer with out the DJI O4 Professional Air Unit, so I needed to set up it myself.

Since that is fairly a small quad, engaged on it is a little more difficult in comparison with bigger drones like a 5-inch, however it’s nonetheless doable with endurance. It took me about half-hour. No soldering is required—simply mount the digicam, air unit, and antennas, plug within the cable, and also you’re good to go. Listed below are the steps.

Take away the antennas from the DJI O4 Professional Air Unit.

Set up the antennas into the TPU holder.

Set up the 4 standoffs behind the body for mounting the air unit.

I most well-liked to run the digicam cable beneath the FC, so I eliminated the FC from the stack briefly.

Set up the O4 Professional digicam within the body.

Reattaching the antennas onto the air unit, plug within the cable from the FC, and mount the air unit onto the standoffs. That’s it!

There’s no must take away the SBUS wire within the O4 Professional cable, as a result of it’s linked to UART1 (particularly RX1) on the flight controller. Because the ExpressLRS receiver is linked to UART2, there’s no battle so long as you’re not utilizing UART1 for anything. If you happen to plan to make use of UART1, you need to take away the SBUS wire within the O4 cable.

Earlier than powering the drone for the primary time, plug in a smoke stopper such because the Vifly Shortsaver, and join a battery and take a look at the drone and see if it powers up appropriately. It’s best to hear the ESC/motor initiation beeps.

Activate the O4 Professional in case you haven’t already: https://oscarliang.com/how-to-setup-dji-o4-pro/#Activation

Pair the DJI O4 Air Unit together with your goggles – Information: https://oscarliang.com/how-to-setup-dji-o4-pro/#Pairing-DJI-Goggles-3-with-O4-Air-Unit-Professional

Firmware

The flight controller (FC) board goal is FLYWOOF722PROV2, and it comes preloaded with Betaflight firmware model 4.5.1. For inventory CLI Diff, see right here. Right here’s the pinout diagram.

ESC Firmware: F4A_4IN1 – AM32 2.16. Listed below are the default ESC settings.

ELRS Receiver Firmware Goal: Flywoo EL24E 2.4GHz RX, firmware model says “merge 481945 CE_LBT”, undecided what model that is however it binds nice with my radio which is on ELRS V3.5.

Betaflight Setup

What May Be Improved

By eradicating pointless elements, I’m hoping to cut back the burden by one other 15–16 grams, which might enable me to make use of a 4S 850mAh LiPo and nonetheless keep beneath the 250g restrict. This may enable 10+ minutes of flight time, which is great for exploring new spots when touring. If there’s curiosity, I can write a publish detailing these modifications—let me know within the feedback!

The FC stack may gain advantage from utilizing plastic nuts as a substitute of metallic lock nuts. Not solely are metallic nuts heavier, however they’re additionally tough to take away whenever you need to work on the FC.

As talked about earlier, mounting the receiver antenna vertically can be supreme. I’m not doing that simply but as a result of I plan to improve to a range receiver, with antennas mounted on each side of the body—identical to I did with the unique Explorer. With that setup and simply 100mW on my T-Lite V2 radio, I used to be in a position to fly out 3km and again.

It’s a little bit of a missed alternative that Flywoo didn’t use their GOKU Nano GPS with an onboard compass. With Betaflight 4.6 bringing place maintain characteristic, this is able to have been an incredible addition. I’m additionally not a fan of the present GPS mounting location—beneath the VTX antennas. I believe it could be higher positioned on the entrance, above the FPV digicam, and away from all of the antennas.

Additionally, there’s no guide included, and the screw baggage aren’t labeled for his or her objective—solely by measurement. It will have saved a while in the event that they have been labeled (e.g., M2x7 for propellers, M2x4 for O4 Professional digicam, and so forth.).

Some Betaflight settings might have been configured extra thoughtfully for the Explorer. For instance, GPS and OSD settings have been left at default. Whereas Flywoo did present a customized PID tune, the filter settings have been largely left untouched. There’s positively room for enchancment in filters, PIDs, and Rescue Mode configuration. I’ll be posting my configuration on Patreon.

Flywoo Explorer Lr4 With Dji O4 Pro Long Range Sub250 Fpv Drone Pid

Inventory PID Settings

Additionally price noting: the present sensor isn’t calibrated correctly – it overestimated present draw. I like to recommend setting the present scale to 440.

Closing Ideas

I’ve been a giant fan of the Explorer LR4 from Flywoo for years—it’s a implausible platform with a great deal of potential. There’s nonetheless room for enhancements, I want Flywoo had accomplished extra than simply improve the FPV system. However total, the Explorer LR4 with the DJI O4 Professional is a implausible long-range FPV drone, particularly for individuals who journey so much and have weight necessities. I’d completely advocate it.