Whereas many FPV drone producers are busy copying one another and releasing near-identical merchandise lately, HGLRC is without doubt one of the only a few firms nonetheless making an attempt to innovate and do one thing genuinely completely different. I’m genuinely impressed by what HGLRC has achieved with the Rekon35 V2, a 3.5-inch micro FPV drone purpose-built for long-range cruising. It’s clear that a number of thought went into this design. After flying it and tearing it down, I’ve gathered loads of ideas—each good and unhealthy. Right here’s my hands-on evaluate.
Inquisitive about flying lengthy vary? Listed here are some sensible suggestions: https://oscarliang.com/long-range-fpv-flying-mini-quad/
The place to Purchase
You should buy the Rekon35 V2 from these distributors:
What’s Included
- 2 units of propellers (8 in complete)
- USB cable for charging
- screws for mounting the props
- screwdriver
- stickers
- handbook
Specs
- Body: Rekon35 V2
- Flight Controller: HGLRC H743 20A ELRS 2.4G 2S V1 AIO
- FC Firmware: HGLRCH743
- Gyro: ICM42688P
- Motors: Specter 1404 5500KV
- Digicam/VTX:
- HD: DJI O4 Lite Air Unit
- Analog: HGLRC Zeus Nano VTX 350mW
- Receiver: Onboard ELRS 2.4G (or 915MHz)
- GPS: HGLRC M100 Mini
- Propellers: Gemfan 3630 triblade
- Supported Battery: 2× 18650 Li-ion cells
- Marketed Weight (with out battery)
- HD Model: 180 ±5g
- Analog Model: 174 ±5g
- Energy Equipment Model: 169 ±5g
- Weight (My Measurements)
- DJI O4 model with out batteries: 187.5g
- With 2× Molicel P30B 18650 cells: 278.5g
Design and Construct
The HGLRC Rekon35 V2 is a 3.5-inch, 2S FPV drone.
Instantly, it stands out due to its distinctive building. The drone encompasses a absolutely enclosed injection-molded plastic physique that protects all inside electronics, giving it a clear, skilled, and sturdy look.
One frequent problem with the DJI O4 Air Unit is overheating when powered on with out airflow. Fortunately, HGLRC addressed this with a big heatsink mounted beneath the air unit. I used to be in a position to go away the drone powered on the bench for over 5 minutes with none overheating warnings, which ought to be even much less of a priority throughout precise flight with fixed airflow.
HGLRC additionally changed the inventory linear-polarized O4 antenna with an extended circularly polarized antenna, enhancing each vary and penetration. Based mostly on my testing, its efficiency is great.
The flight controller and motors are mounted on a carbon fiber plate, with 3mm-thick arms that really feel very stiff and strong.
There are two rows of vivid RGB LEDs on both sides of the drone. Fly this factor at night time and it genuinely appears like a tiny UFO gliding by the air. The LEDs are configurable in Betaflight and can be utilized to show helpful info similar to GPS standing, throttle degree, or battery voltage degree. Out of the field, they default to a rainbow impact.
Study configuring Betaflight LED on this information: https://oscarliang.com/setup-led-betaflight/
The drone is powered by two 18650 cells housed in a hinged battery compartment (battery shouldn’t be included). Merely insert the batteries and also you’re able to fly.
Even higher, you possibly can go away the batteries contained in the drone and cost them immediately through the USB-C port on the rear like a DJI Mini, which is extremely handy.
The “no uncovered wires” design is considered one of my favourite elements—all the things appears clear, modern, and properly protected.
You’ll be able to entry the DJI O4 Air Unit’s USB port and bind button from the edges of the drone.
To attach the drone to Betaflight, there’s one other USB-C port positioned slightly below the charging port. You’ll must push the spring-loaded antenna mount downward to entry it.
Battery – It Solely Takes 18650!
Open the battery compartment by holding down the 2 locking tabs and lifting the duvet to disclose the battery tray—simply probably the most fascinating side of this drone.
The Rekon35 V2 does NOT assist LiPo battery. As a substitute, it runs on two particular person 18650 Li-ion cells—sure, the identical cylindrical batteries you’d usually use in radios, flashlights, or vaping units.
At first, this may sound limiting, but it surely’s really the core id of the drone: long-range.
Li-ion batteries are extraordinarily common for long-range FPV, however they’re normally assembled right into a battery pack and linked to the drone through an XT30 or XT60 connector like an ordinary LiPo. Immediately inserting particular person 18650 cells into the drone itself is genuinely distinctive. Whereas we’ve got seen related concepts earlier than, they had been restricted to 1S setups—that is the primary BNF FPV drone to do it on 2S.
Beneficial 18650 Batteries
I’ve examined many various 18650 cells: https://oscarliang.com/best-18650-li-ion-battery/
Listed here are my suggestions:
Best choice
Good Alternate options
Essential: The battery holder solely helps flat-top cells. Button-top 18650s is not going to match.
Tear Down: What’s Contained in the Drone?
Disassembling the Rekon35 V2 is easy. There are solely 6 M2 hex screws securing the plastic physique to the body.
The very first thing that stunned me was the unconventional flight controller design. It seems HGLRC might have designed this board particularly for the Rekon35 V2—it’s lengthy and rectangular fairly than the same old sq. form. That is an all-in-one (AIO) board, integrating the ESC and ELRS receiver onto the identical PCB. The upside is a really compact format; the draw back is that if any main part fails, you’ll want to interchange all the board.
The GPS module is the HGLRC M100 Mini, which I examined final yr and located to be glorious. Regardless of its tiny measurement, it makes use of a u-blox M10 chip, delivering sturdy efficiency. I usually get a GPS repair in about 1.5 minutes with 8 satellites, and after 10 minutes it usually locks onto 19 satellites.
The digicam angle is adjustable, however you’ll must take away the entrance cover to entry the mounting screws. Out of the field, the angle is ready to round 20 levels, which is good for long-range cruising, so I didn’t really feel the necessity to change it. In the event you steadily modify digicam angle, you would most likely drill a small entry gap within the cover to keep away from eradicating it every time.
The drone additionally comes with a small bodily beeper hidden between the 2 USB port within the rear, which is fairly loud. In the event you crash in bushes or tall grass, this might be extraordinarily useful for restoration.
Flight Efficiency
Clean, Quiet, and Surprisingly Refined
The very first thing I observed is simply how quiet the Rekon35 V2 is. It’s shockingly low-noise for a 3.5-inch drone—you possibly can barely hear it from 100 meters away, even when doing flips and rolls. It’s excellent for discreet cruising.
The second shock was how steady and clean it feels within the air. It comes with a reasonably aggressive PID and filter tune, which is strictly what I prefer to see in a BNF. This actually reveals that HGLRC put real effort into tuning fairly than transport a generic setup.
However It’s Not Quick
It hovers at round 30% throttle at takeoff. At first, it feels moderately agile—you possibly can even do some freestyle strikes like flips, rolls, and split-S maneuvers. Nonetheless, a couple of minutes into the flight, you possibly can really feel the drone slowly dropping punch resulting from voltage sag, and it turns into more and more dangerous to aim aggressive maneuvers as you’re continually warned about low voltage.
This isn’t a freestyle machine; it’s greatest fitted to relaxed cruising.
Prime pace is round 70–80 km/h, and cruising usually sits between 40–50 km/h at roughly 40–45% throttle.
Lengthy Flight Time
The marketed 15-minute flight time is pretty correct for sluggish cruising. Realistically, you need to count on 13–14 minutes when you fly up and down steadily and blend in some freestyle strikes right here and there, particularly with some wind.
In calm situations with regular cruising, overlaying 10km or extra is totally achievable.
Not the Greatest in Windy Situations
The Rekon 35 V2 doesn’t deal with wind significantly properly. In 20mph wind, the quad struggled considerably and was barely shifting into headwind.
With LiPo batteries, you would usually simply punch by wind, however with Li-ion cells, there may be little throttle response resulting from voltage sag. In the event you fly too far out in windy situations, there’s an actual threat it’s possible you’ll not make it again, so keep away from pushing distance when wind is powerful.
GPS Rescue Labored Nicely
GPS Rescue is configured out of the field, and failsafe is ready to Rescue mode.
In my testing setting, GPS Rescue labored properly and introduced the drone again near the takeoff level.
That stated, you need to all the time double-check your Rescue mode settings to make sure they fit your flying setting.
Take a look at my information on Rescue Mode: https://oscarliang.com/setup-gps-rescue-mode-betaflight/
Present Sensor Wants Calibration
My Molicel P30B has an precise capability of round 2851 mAh, however the OSD reported 6036 mAh—greater than double the true worth. The present sensor scale clearly wants calibration.
Limitations and Potential Enhancements
With this quad, battery high quality issues lots. It’s essential to use respectable 18650 cells—low cost or counterfeit batteries will utterly smash the expertise. Sadly, pretend 18650s are frequent on eBay and Amazon, which might frustrate newbies who aren’t accustomed to sourcing high quality cells.
The drone can also be barely heavy for a 3.5-inch quad, weighing 187g with out batteries. In case your purpose is to remain beneath the 250g weight restrict, this might not be the most suitable choice out of the field. That stated, I have already got a couple of concepts to scale back weight and enhance effectivity, and I imagine it ought to be doable to carry it beneath 250g. I’ll attempt to cowl these modifications in a future put up or replace this evaluate after the New 12 months when I’ve extra free time.
Battery Charging
You’ll be able to cost the batteries contained in the drone through USB-C, with a charging energy of round 11–12W. This implies it takes roughly 2 to 2.5 hours to completely cost two 3000mAh 18650 cells.
Charging seems to cease at round 4.15V per cell, which is definitely a great signal—it doesn’t overcharge. Nonetheless, it doesn’t attain the complete 4.20V, so that you’re doubtlessly dropping a tiny quantity of capability (roughly 50mAh, or about 10 seconds of flight time). In observe, that is negligible.
In the event you choose, you possibly can take away the cells and cost them with a devoted 18650 charger, or perhaps a LiPo charger utilizing a DIY holder like this. These strategies are more likely to be a lot sooner and ensures a full 4.2V cost. Nonetheless, charging immediately contained in the drone is extraordinarily handy, excellent for lazy individuals like me 🙂
Tips on how to Setup
Handbook could be very useful.
Firmware
- FC Board: HGLRCH743, comes with BF 4.5.2
- ESC Firmware: Bluejay, 0.21.0 (F-H-40)
- ELRS Receiver: HGLRC Hermes 2.4GHz RX (3.5.3 firmware)
Binding ELRS receiver
Detailed directions may be discovered right here: https://oscarliang.com/bind-expresslrs-receivers/
Pairing DJI Goggles
Comply with the directions right here: https://oscarliang.com/how-to-setup-dji-o4-lite/#Pairing-DJI-Goggles-3-with-O4-Lite. The O4 doesn’t require activation, so you possibly can fly as quickly because it’s paired.
Betaflight Setup
- Energy & Battery tab: The settings are left at Betaflight default, that are for LiPo batteries, so low-voltage warnings will set off method too early. For 18650, you need to set Minimal Cell Voltage to 3V (relies on the cells you might be utilizing, some can safely go as little as 2.8V and even 2.7V). Most Cell Voltage to 4.2V. Warning Cell voltage to three.2V. Present sensor scale additionally wants altering – I’ll publish my worth on a later date.
- PID Tuning tab: Arrange your personal charges.
- Modes Tab: Configure your arm swap, angle mode, and turtle mode. For steerage, see this tutorial: https://oscarliang.com/betaflight-modes/#How-to-Setup-Arm-Swap
- Receiver tab: Allow Telemetry
- GPS tab: My standard settings are to allow “Use Galileo” and “Set Dwelling Level As soon as”, set Floor help Kind to Auto
- OSD tab: Customise to your desire.
Putting in Propellers
Insert the translucent bushings into the prop hubs, mount them on the motors, and safe every prop with two screws.
Essential: The Rekon35 V2 makes use of reversed motor course.
That’s it—your Rekon35 V2 ought to now be prepared for its maiden flight.
Closing Ideas: Is the HGLRC Rekon35 V2 Value It?
The HGLRC Rekon35 V2 is a daring experiment—a drone constructed solely round 18650 Li-ion. One essential level is that you have to use good-quality cells; poor batteries will end in irritating efficiency.
HGLRC clearly invested a number of effort into the design. That is probably the most well-thought-out Li-ion-only FPV drone I’ve examined to this point. GPS Rescue works properly, the quad is environment friendly, quiet, clean, and cleverly engineered.
Get the Rekon35 V2 from:
That stated, I do want HGLRC had made the drone lighter, ideally retaining it beneath the 250g weight restrict. Because it’s not designed for freestyle or high-speed flight, the cumbersome building feels pointless. I imagine a big portion of the plastic may very well be eliminated to scale back weight.
Even in inventory type, a 5 km spherical journey is solely doable, which is spectacular. Making it lighter would solely improve its potential.
The Rekon35 V2 shouldn’t be excellent, but it surely’s genuinely fascinating. And in a interest filled with look-alike drones, that alone is refreshing.