The aim of this construct is to make a 7″ FPV drone as affordably as attainable whereas nonetheless attaining greater than 5km vary. I managed to supply all of the elements for round $150, delivering efficiency that surpasses the $215 Darwin129—generally thought-about because the “most cost-effective 7-inch” from DarwinFPV. Sounds promising, proper? Let’s dive into the elements I used, and I’ll share my expertise with constructing and flying this setup.
Should you’re new to FPV, try my FPV Drone Construct Information, the place I cowl many ideas and methods about drone constructing: https://oscarliang.com/how-to-build-fpv-drone/.
In case you are new to lengthy vary flying, try my tutorial on the matters: https://oscarliang.com/long-range-fpv-flying-mini-quad/.
Components Checklist
Listed below are the inexpensive {hardware} I chosen for this construct:
Complete: US$152.77
Notice that this value doesn’t embrace import tax and delivery prices, which may differ by area. You’ll additionally want a battery, and I’ll provide ideas on what to get later on this construct log.
Flight Time and Vary
With this construct, I used to be capable of obtain the next flight time, flight distance, and vary utilizing a 6S 3600mAh Li-ion battery pack:
In calm climate circumstances (~12km/h wind):
- Max Flight Time (touchdown at 2.8V/cell): 18 minutes 40 seconds
- Max Flight Distance (touchdown at 2.8V/cell): 16,100 meters
In ~27km/h wind, with a tailwind outbound and headwind inbound:
- Max Flight Time: 14 minutes 30 seconds
- Max Flight Distance: 13,050 meters
- Vary: 5km+ simply (I may have pushed additional, however I turned again after reaching 5km because of the windy circumstances)
Inexpensive 7″ FPV Drone Package
This funds 7″ FPV drone equipment contains the body, 4 2806.5 motors, a set of propellers, an F405 flight controller, and a 45A 4in1 ESC—all for simply $105, which is unbelievable worth!
Get this equipment on AliExpress: https://s.click on.aliexpress.com/e/_DFAJ26n
This equipment presents a lot of the trendy options you’d need in a 7″ long-range construct in 2024, at a fraction of the price. Nonetheless, there are some drawbacks that is perhaps deal breakers for some customers, which I’ll delve into extra particulars now.
Body
I actually just like the design of this body—it has a protracted physique that may accommodate a big battery on prime, with varied mounting holes for various FC stacks and VTX. Meeting and constructing this body are easy regardless of the dearth of directions.
This 7″ body weighs round 120g, which could be very mild for this class. Nonetheless, the arms are solely 5mm thick, and the highest and backside plates are 2.5mm thick. The development feels a bit flimsy, and it’s not as sturdy or stiff as I’d hope for a 7″ FPV drone. A body that lacks stiffness can contribute to vibrations and tuning points, which may impression flight efficiency. However we simply need an inexpensive body to get us within the air, it will suffice for now.
Flight Controller
The flight controller is the YSIDO F4 V3S Plus FC, and on paper, it has spectacular specs.
Firstly, it makes use of an F405 processor, permitting you to run 4K PID loop frequency and DShot300 with GPS enabled.
It has 3 UARTs, which is sufficient for my wants:
- UART1 for RX
- UART3 for IRC Tramp
- UART6 for GPS
It contains 5V and 9V BECs, in addition to 4.5V pads—these are mainly 5V pads that may draw energy from the USB port, so that you don’t must plug within the battery when testing the receiver or getting a GPS lock earlier than takeoff. The 9V BEC is nice for powering the VTX, which additionally provides additional filtering.
It even has a barometer (BMP280), which is shocking for a funds FC. The primary draw back of this board is the MPU6500 gyro, which is noisier and tougher to tune than different gyros.
The FC firmware goal is OMNIBUSF4SD, and it comes with Betaflight 4.1.1 firmware from 2019, so it undoubtedly wants an replace to benefit from newer options like GPS Rescue.
I deliberate to tune filters and PID settings, however the SD card for Blackbox logging cracked in a minor crash, and I don’t have a spare readily available. This brings up a possible design flaw within the FC: the SD card slot location – when inserted, the SD card stands out and is uncovered to break in crashes.
Given the noisy gyro, enabling RPM filter is a should—it flies extra stably, and the motors come down cooler. I’m at present utilizing UAVTech’s 7″ preset; the quad nonetheless wobbles a bit, but it surely’s undoubtedly higher than the default settings.
ESC
The 45A 4in1 ESCs included aren’t notably highly effective, however they’re greater than satisfactory for this construct. A 14AWG XT60 pigtail and a 35V 560uF capacitor are additionally included.
Sadly, the present sensor on this ESC doesn’t appear to work—adjusting the dimensions doesn’t change something. I’m undecided if it is a widespread situation or if I simply have a defective unit. No large deal, I’ll simply monitor battery utilizing voltage.
It comes with BLHeli_S 16.7 firmware (J-H-30). I like to recommend flashing Bluejay to those ESCs, because it means that you can allow the RPM filter in Betaflight, considerably bettering flight efficiency. I’ve a information on find out how to flash Bluejay: https://oscarliang.com/bluejay-blheli-s/
After I tried flashing Bluejay, I initially couldn’t learn one of many ESC within the configurator. Nonetheless, swapping the ribbon cable (which connects the ESC to the FC) with the spare one mounted the problem—this might have been a foul cable. I flashed the most recent model with a 48kHz PWM frequency.
Motors
The included motors are YSIDO V8 S2806.5 1300KV.
There are different kits that provide taller motors i.e. 2807 1300KV. I used to be tempted to go for these as a result of giant quads like 7″ can profit from bigger motor stators, however they’re costlier. After a lot consideration, I made a decision in opposition to it as a result of the distinction could be minimal if I’m simply cruising—except you wish to do freestyle with it then the 0.5mm taller motors may make sense.
Video Transmitter
When choosing the VTX for this construct, my essential concerns have been:
- Low price
- Excessive output energy (1W or larger)
- Straightforward mounting within the body (e.g., 30x30mm or 20x20mm mounting)
- Help for SmartAudio or IRC Tramp for VTX settings adjustment within the OSD menu (VTX Management)
- Vast enter voltage assist
The most affordable 1.6W VTX I may discover was the Ultra1600 for under $22.
Get the Ultra1600 VTX on AliExpress: https://s.click on.aliexpress.com/e/_DmxIABp
Though it didn’t fairly hit the promised 1.6W in my testing, it’s nonetheless price contemplating given the low value—observe {that a} brand-name 1.6W VTX would usually price double or extra. In order for you a real 1.6W VTX, the iFlight Blitz and Speedybee TX1600 are good alternate options, however these may solely provide you with lower than 20% vary enchancment.
There’s additionally a VTX from JHEMCU that’s even barely cheaper, but it surely has no heatsink, so it is perhaps much less dependable: https://s.click on.aliexpress.com/e/_DlBNAfZ
VTX Desk for the Ultra1600:
# vtxtablevtxtable bands 5vtxtable channels 8vtxtable band 1 BOSCAM_A A CUSTOM 5865 5845 5825 5805 5785 5765 5745 5725vtxtable band 2 BOSCAM_B B CUSTOM 5733 5752 5771 5790 5809 5828 5847 5866vtxtable band 3 BOSCAM_E E CUSTOM 5705 5685 5665 5645 5885 5905 5925 5945vtxtable band 4 FATSHARK F CUSTOM 5740 5760 5780 5800 5820 5840 5860 5880vtxtable band 5 RACEBAND R CUSTOM 5658 5695 5732 5769 5806 5843 5880 5917vtxtable powerlevels 4vtxtable powervalues 25 400 800 1600vtxtable powerlabels 25 400 800 1W6save
FPV Digicam
When selecting an FPV digital camera, search for one with respectable specs like a large FOV, giant sensor, switchable side ratio (ideally native 4:3), 19x19mm kind issue (micro dimension), low minimal illumination (for higher low-light efficiency), adjustable settings, and so on. Nonetheless, you may’t belief every little thing you see on the product web page—there’s a cause these cameras are so low-cost.
That is the digital camera I picked https://s.click on.aliexpress.com/e/_DEijX7N
The picture high quality is fairly respectable, and I feel it’s higher than the one within the Darwin129 BNF quad.
The primary criticism I’ve is with the fisheye impact—while you do flips and rolls, the picture can look barely distorted. It’s probably not an issue although when flying straight. That is one thing I discover very often with funds FPV cameras, but it surely’s not a deal breaker since we’re primarily cruising throughout long-range flights.
GPS
A GPS module is a should if you happen to plan to fly long-range. With Betaflight Rescue mode, your quad can mechanically return to the launch level or by command if you happen to lose sign or orientation.
That is the $4 GPS I’m utilizing: https://s.click on.aliexpress.com/e/_DdyGkeH
It’s actually inferior to costlier counterparts, but it surely will get the job executed. I’ve used these on a variety of my funds builds, and so they work as meant. They often get round 8 to 10 satellites after 3-5 minutes of being powered on, which is the minimal for Rescue mode to perform correctly. Should you can afford a costlier GPS, undoubtedly go for it! Listed below are my GPS suggestions: https://oscarliang.com/gps-review/#Suggestions
I’m mounting the GPS on the battery strap, which I discovered to be an excellent place for it—it’s properly away from the video transmitter and antennas, with no obstructions that might intervene with reception.
Radio Receiver
That is the most affordable ExpressLRS receiver I’ve come throughout from BAYCK: https://s.click on.aliexpress.com/e/_Ddi9WEf
I’m fairly pleased with its efficiency, and I’d purchase it once more. The firmware goal is BAYCK 2.4GHz Nano RX, it comes with ELRS model 3.3 firmware.
VTX Antenna
Get a protracted antenna for the VTX so it doesn’t get blocked by the body or battery when flying away or turning again.
That is what I purchased, and it really works properly: https://s.click on.aliexpress.com/e/_DCnUoJZ
Propellers
A set of propellers is included within the body equipment, so that you don’t have to purchase them individually, but it surely’s good to have spares.
The body equipment comes with Gemfan 7040 triblades: https://s.click on.aliexpress.com/e/_Dcffy47
These are the 7inch props I’d suggest as an improve—HQ DP 7×3.5×3-v1s (Greatest all-rounder):
Further Supplies
Battery
For lengthy vary, undoubtedly think about using a Li-ion battery pack for prolonged flight occasions. Most Li-ion battery packs you should buy off the shelf don’t use the perfect cells, so if you’d like the absolute best efficiency, think about constructing your personal battery packs utilizing particular person cells. Right here’s my information on Li-ion cells suggestions and how-to construct one: https://oscarliang.com/best-18650-li-ion-battery/
Nonetheless, not everybody has the time or abilities to make one from scratch. On this case, shopping for a ready-made battery pack from a well known model may very well be an excellent choice. Truly, I used battery packs from Auline with this 7″ construct, and so they labored fairly properly. True, they aren’t very punchy, however for long-range cruising, they’re completely succesful. Right here’s my evaluation and testing of the Auline 6S 4000mAh battery: https://oscarliang.com/auline-6s-4000mah-45a/
In contrast to LiPo the place you’re suggested to land when voltage reaches 3.5V per cell, you may discharge Li-ion battery a lot decrease, usually down to three.0V per cell, and even 2.8V per cell. It depends upon the specs of your Li-ion cells, examine the minimal voltage it may well safely deal with.
Constructing Steps
Assembling the Body
Mounting the Motors
Mount the motors on the arms utilizing the supplied screws. I like to recommend utilizing threadlocker on the screws in order that they don’t simply develop into free over time: https://oscarliang.com/threadlock/
Putting in the FC Stack
Earlier than putting in the FC and ESC stack, safe the 4 metal bolts in place utilizing 4 M3 metal nuts.
Set up the 4-in-1 ESC within the body, and solder the motor wires to the pads. Solder the capacitor and XT60 pigtail to the ESC.
Set up the flight controller, join it to the ESC utilizing the ribbon cable. Then join/solder all of the elements to the FC: GPS, radio receiver, VTX, and FPV digital camera.
Right here’s a wiring diagram for the YSIDO F4 V3S Plus FC.
Right here’s one other angle displaying how I mounted these elements within the body.
Right here’s a close-up of the soldering/wiring.
Ending Off
Set up the highest plate, and mount the GPS on the LiPo strap—and that’s it. Don’t neglect to safe all of the wires with zip ties too. The all up weight (with out battery) is 473g.
Betaflight Config
I’ll share my quad’s settings and CLI dump at a later date.
What’s Improper with Darwin129
DarwinFPV is a well known producer for low-cost pre-built drones, and so they provide a really inexpensive 7″ BNF drone that gives nice worth—so why trouble constructing your personal? Properly, even with the funds elements on this customized construct, it outperforms the Darwin129. As I discussed in my full evaluation of the Darwin129, it has a number of downsides:
- The Darwin129 solely helps a 4S battery, whereas the upper voltage 6S considerably advantages effectivity and energy—essential for bigger long-range builds.
- The Darwin129 doesn’t fly very properly and requires further tuning, which defeats the aim of “bind and fly.” It has a number of jello and vibration, which I’m not even positive may be eradicated by way of tuning—it may very well be essentially hardware-related.
- The included GPS doesn’t work in any respect, so that you’ll need to spend additional on a distinct GPS, solder it, and configure it.
- Actually, constructing your personal funds 7″ will price rather a lot lower than shopping for the Darwin129.
Conclusion
That is the most affordable 7″ FPV Drone I’ve constructed thus far. It presents a sturdy basis for a extremely succesful long-range construct at an unbelievable value. The {hardware} feels trendy and feature-packed, providing wonderful worth for cash. With a number of rigorously chosen funds elements, this construct permits for a low-cost 7″ long-range drone.