4" Freestyle / 5" Long Range
Here you'll find links to the best performing products for 4" Freestyle and 5" Ultralight drones based on my testing over on AOS Labs and my own experience and research. Some of these links are affiliate links (affiliate policy).
Motors
Emax ECO II 2004
The Emax ECO II is a solid mid range motor at an exceptionally low price point. These 2004 motors provide comparable power and efficiency to motors costing twice as much. They are well matched to a 5" biblade, a 4" triblade, or 3.5" bullnose prop.
RCinPower GTS V3 2104
A beautifully made and high performance 2104 motor from RCinPower. Whether you go for the M2 mouting system (you will need to drill out your props by hand) or the standard T-mount version this is a fantastic motor for 4" freestyle or 5" Ultralight builds.
T-Motor F2004 1700KV/3000KV Motor
It's hard not to recommend a T-motor product when one exists in the right size and KV for your application. The F2004 1700Kv is well matched to a 6S ultralight 5" setup. The 3000KV is better for 3.5 - 4" setups on 4S.
Electronics Stack
GEPRC F722 AIO - F722 FC+ 35A 2S-6S BLS ESC
For up to 4" Props a 25mm AIO is where it's at. This AIO has everything: 6S 35A rating, F7 processor, DJI Plug and 16MB of Blackbox storage. Yes please!
A great 20 x 20 mm budget electronics stack. The 35A rating will be suitable for most 5" builds UNLESS you are using the most powerful 2207 motors available (e.g. AOS Supernova). Don't let anyone tell you an F4 + 35A BLHeli_S is not enough to have an amazing FPV experience!
SpeedyBee F405 Mini Stack - F405 V3 FC + 35A 3-6S BLHeli_S 4-in-1 ESC - 20x20
A great 20 x 20 mm budget electronics stack. The 35A rating will be suitable for most 5" builds UNLESS you are using the most powerful 2207 motors available (e.g. AOS Supernova). Don't let anyone tell you an F4 + 35A BLHeli_S is not enough to have an amazing FPV experience!
Skystars Fly Stack - F722 Mini HD Pro FC + KM55 55A AM_32 3-6S 4-in-1 ESC - 20x20
This is the dark horse of 20 x 20 mini stacks with a very special secret. F7 processor and 55A AM_32 ESC. AM_32 outperforms BLHeli_32 on my test stand and depite my best efforts torture testing motors I have been unable to kill this thing. For a high power 5" quad I wouldn't buy anything else today.
Holybro Kakute G4 AIO - G4 FC + 35A AM_32 ESC
A 25mm AIO with 16MB of Blackbox and DJI plug paired with a 35A AM_32 ESC. Sign me up.
VTX
Walksnail Moonlight Kit 4K Avatar VTX Kit
The top of the line Walksnail Avatar VTX. Onboard 4k60 recording and 1080p60 or 720p100 video in the goggles. The image quality is not as good as DJI O3 but the price is much more reasonable and this camera does better in low light.
Foxeer HDZero Race VTX
Foxeer made a HDZero Race VTX! I actually prefer the specs of this VTX to the HDZero one because it can be powered from up to 6S LiPo voltage! Everything else is the same as the HDZero Race V3.
HDZero Freestyle V2 VTX
True 1W output power for the HDZero system just got better. The smaller 30x30x14 mm form factor and 20mm M2 mounting pattern make this VTX perfect for 3" - 5" Freestyle drones and pilots who want the lowest possible latency of any FPV system available today. De-cased the VTX can be used on Lightweight 3" builds.
Rush Tank Ultimate Plus 5.8GHz VTX
A solid choice for Analog with a high transmit power and good reputation for reliability.
DJI O3
The DJI O3 system pushes digital FPV in a new direction. Here the focus is onboard recording and image quality at the expense of latency. It is a great looking system, some pilots are reporting issues with vibration sensitivity of the IMU used for electronic image stabilisation, hopefully this will be resolved in a future firmware update.
Caddx Vista Nebula Pro Kit
The Caddx vista is a great option for DJI pilots who prefer to record their HD footage on a Go Pro.
Receiver
MATEKSYS ExpressLRS 2.4GHz Receiver - ELRS R24 TD
I've made my mind up. I'm only recommending ELRS moving forward. At this point it does everything better than any other radio link. LoRa for range and penetration, yes. 1000Hz update rate for crazy low latency, yes. Loads of manufacturers are making receivers for ELRS and I think this diversity offering from Matek (antenna diversity only) is certainly among the best performing and most reliable.
Happymodel ExpressLRS Nano 2.4GHz EP1 RX
Happymodel were the first to bring out ELRS hardware and their EP1 and EP2 receivers closely follow the developers reference design and are incredibly tiny. I lean towards the EP1 as the UFL antenna is much higher performing than the ceramic antenna on the EP2.
Props
Gemfan Hurricane 4023
Gemfan manufacture durable and high performing props. Their Hurricane blade profile is more agressively tapered which improves efficiency while still providing good top end power. The main benefit of these props is that they support both T-mount and 5mm mounting!
HQProp 4x4.3x3 V1S
HQ make durable high performing props and their V1S blade profile combines efficiency with great top end thrust and power. The limitation with this prop is that it is only compatible with 5mm prop shafts.
HQProp Durable T5x3
This is an exceptionally efficient T-mount 5" prop, it's well matched to 2004/2104 size motors and perfect for 5" long range or 5" toothpick quads.
Batteries
GNB 850mAh 120C LiHv
A great performing pack for 4S 3" or 3.5" drones. Energy density, power density and voltage sag are all excellent. The larger 850mAh capacity will extend flight times compared to a typical 650mAh pack but is a little heavier, of course.
TATTU R-Line 750mAh
Tattu packs are expensive but you can't fault the performance. Strong burst performance and good energy density with minimal voltage sag. Similar performance to the 550mAh but scaled up!
XILO 850mAh 6s 100c Lipo Battery
850mAh on 6S is a good size for 5" Ultralights. A 100C rating is typically designed for flight applications. Anything less than 50C is for ground vehicles. Battery availability depends on where you live and who will ship LiPos to you. This is a good value option from XILO.