HappyModel Sailfly-x review; best value quad I've reviewed in 2019 so far

The Happymodel Sailfly-X is available with free shipping internationally for around $88

Introduction
​I'm a scientist by training so not usually one to use hyperbole (especially where it feels click-baity in titles) but I really do mean it here: This is the best value quad I've reviewed so far this year. It is not the best long range, it is not the best free-style and it is not the best racer. But for those occasions where you are looking to fly in a small to medium park, empty office or commercial area out from your back yard which is 90% of my fling, this is the ideal tool for the job.

The HappyModel Sailfly-x is a "toothpick class" ultralight micro quadcopter. It has an all up weight of 38g without battery and can take 1s, 2s or 3s batteries. It is available with onboard FRSKY, FlySky or DSM reveivers or without a receiver where you can add crossfire or anything else. It is a fairly complete kit (see below) and is available for just $88 at full retail. Availability seems to be somewhat limited to Banggood at time of writing but my guess is that many retailers will pick this one up.

For this review I'll break down what is included, the specs, document differences from the stock betaflight and then cover off in the actual review performance on 2s, 3s, FPV performance and close with a summary and my recommendations. I'll also list spares and upgrade parts as the become available.

Pretty good list of parts for $88

What is included?

• 1x Sailfly-X FPV Racing Drone (see specs below)
• 1x 3D Printed 30 Degree Angle Canopy ( Red) (BG listing is wrong - red is 40°)
• 1x 3D Printed 40 Degree Angle Canopy ( Purple) (BG listing is wrong - purple is 30°)
• 1x 3S 11.4v 300mah 30C/60C battery (nice to have this included on such a low cost model)
• 8 x propellers (this is missing from BG listing)
• 1x Propeller disassemble tool (meh)
• 1x Screwdriver (useful but if you are like me you probably have a dozen of these by now!)

Specs and what this means

Crazybee F4 V2.1 2-3s Mainboard: This is the single-board brains behind this quad and features an f4 flight controller, BLHeli_S DSHOT600 capable 4 x 5a ESC and onboard reciever (flysky, frsky, dsm). It has 2 full UARTs: one for smart audio VTX control and 1 spare you can use for an external reveiver. V2.1 offer the minor improvements over V2.0: plug for AIO camera attachment, stronger solder pads and better through-holes.

EX1102 8500KV Motor: These are super-light motors at 2.7g each and nicely built. Best news is that compared to the prototypes and those found on the Mobula7HD they have 1.5mm shafts (instead of 1.0mm) and a much more suitable kV of 8500. I'm impressed by these little motors

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