Starter pack - Kayoumini 2.5"

Interested or already an owner of a Kayoumini 2.5" ? The starter pack was made for you!

The purpose of this page is to bring together all the useful information you'll need to build your quad around this frame.

Summary

Quick Access

Kayoumini ?

Build tips

Electronics recommendations (2S Setup )

Quick Access

Where to buy ?

Kayoumini 2.5" (Frame Kit)
Kayou Spare/3D Prints

Useful links :

Official Printables (3D prints STL files and documentation)
Betaflight/Bluejay Preset

Kayoumini ?

the Kayoumini 2.5” aims to reproduce as faithfully as possible the flight feeling of a perfectly downscaled 5” Freestyle Quad.

The Squished X geometry and Long deck (top mounted LiPo) gives it very different flight characteristics than a toothpick, and makes it very enjoyable to zip around narrow spots.

With builds weighing in at under 100g AUW (incl battery) this little boy is the ultimate urban ripper. Low noise level and agility will allow you to unlock new spots and to send it without bothering your neighbors !

A few key points :

3mm thick unibottom, extremely rigid,
2mm thick top plate,
25.5*25.5 (whoop) and 20*20 mounting holes,
Optimized for analog (with 8mm standoffs included)
HD whoop VTX compatible (Walksnail, Hdzero) (with 12mm standoffs included)

Downscaling

This is one of the most important aspects of this frame : Downscaling, flight feeling and power to weight ratio.

The Kayoumini 2.5" was fully conceived around getting that downscaled 5" Freestyler feeling : hitting full gas won't take you to the moon like a 6s Toothpick or a full scale 5” Freestyle quad, and that's the point ! It'll send you just far enough to extend your lines and rip your local park like a mini bando.

With the recommended 2s setup, you'll find the throttle curve, visual cues and sensations of a 5“ quad properly scaled down to 2.5”, i.e. 2 times smaller, and that's just beautiful.

This point is easy to shown by comparing the thrust-to-weight ratio of a few different type of quads,

The Kayoumini's thrust-to-weight ratio has been thought to be very similar to a classic 5” freestyle setup to get as close as possible to its flight feeling !

Build tips

For this category we'll be going for 25.5*25.5 AIO whoop boards to keep the weight down and the build as compact as it gets.

We're talking 55-65g without lipo, and the recommended voltage is 2s.

Standoffs length

The frame is sold with 2 standoffs options to keep the build as light and compact as possible for all uses :

8mm : Analog

The bare minimum :

Enough room to fit an Analog AIO. (Integrated RX and VTX, check recommendations below).
You can squeeze an external Analog VTX in there (TBS Unify Nano style) if needed.

12mm : HD, or taller builds

Dual PCB option : AIO + HD VTX (Whoop style : Walksnail or Hdzero)

Standoffs are standard Aluminum M2, if you want to play around with different lengths feel free to grab some on Aliexpress !

Build examples

Struggling with assembling and positioning ? Nothing better than a few photos to answer all your questions.

Analog setup based on a Happymodel X12 and a Runcam Nano 3.

Electronics recommendations (2S Setup )

This is by far my favorite setup, and the one we recommend (2S Setup): you end up with a light, responsive, playful build that will let you have fun freestyling tight spots without going to the moon on the first powerloop.

Useful informations :

We recommend a minimum of 12A FETS on the ESCs to ensure good reliability.
You'll need to remove the motor connectors for the AIOs sold with them. (pretty quick to do).

Analog Base

AIO 4in1 (1S-2S ESC+FC+VTX+RX)

1 single board for all the electronics ! Analog is clearly the preferred choice for the Kayoumini, it's easy to build, compact, lightweight and it will deliver the best flight performances.

JHEMCU F411 ELVTX

Entry-level

VTX : 400mW, UFL
RX : Serial, UFL

Unbeatable price.

Happymodel X12

Mid-range

VTX : 350mW, UFL
RX : SPI, Ceramic Antenna

You can grab the "PNP" version without an integrated Receiver and throw an external one if needed (Crsf, Ghost etc)

Flywoo GOKU F405 ERVT

High-end

VTX : 400mW, UFL
RX : Serial, UFL

Renowned brand, the top of the AIO range.

FPV Camera (Analog)

Kayoumini fits 14mm cameras, TPUs are available on Printables for the most popular cameras on the market.

RUNCAM NANO 4

21.90e

Excellent weight/price/image quality ratio for the format.

CADDX ANT NANO

19.90e

Very similar to the Runcam Nano 4, a good alternative.

CADDX BABY RATEL 2

31e

Analog's top-of-the-range 14mm cam, and the price that goes with it.

HD Base

Camera + VTX Combo (HD)

3 manufacturers are producing whoop sized Digital hardware : DJI, HDZERO and Walksnail.

Theses 2 combos will fit between the 12mm standoffs supplied with the Kayoumini 2.5".

DJI Air Unit O4 (aka Lite)

HDZERO Whoop Lite Bundle

Walksnail AVATAR HD MINI 1S LITE

AIO 3in1 (2S ESC+FC+RX)

As you'll be using an external VTX you don't need an integrated Analog one in your AIO.

JHEMCU F411 ELRS

Entry-level

BETAFPV F4 1S 12A ELRS 2.4G V3

Mid-range

Happymodel X12 Lite

Mid-range

VTX-less version of the classic X12.

Other parts

Motors

The 2s 2.5” baseline is 1103. Feel free to go bigger for more power, smaller to save weight, or play around with different Kv.

Pick the perfect Kv !

As mentioned above, the Thrust-to-Weight ratio that gets us closest to the flight feel of a 5" freestyle mini quad is 7.8.

So we've calculated and plotted the curve of the optimal Kv based on weight to hit exactly the flight feel you're aiming for, depending on your build!

Here's what we recommend :

SparkHobby XSPEED1103 8500KV

7.50e

Outstanding quality for an unbeatable price.

Happymodel 1103S

8.75e

Entry-level, excellent value for money.

BetaFPV LAVA Series 1104

13.00e

High end high quality motor, 1104 will give you great punch without popping out of the carbon frame designed for 11xx motors.

Only available in 7200kv, so mostly suited for lightweight Analog builds.

LiPo

The deck is only 50mm long, so be careful which lipo you choose. We recommend 2s 300-450mAh for a flight time of 3 to 6 minutes, depending on how hard you push it.

Flywoo Explorer 420mAh HV 2S 80C

Legend has it that they were born for the Kayoumini. They fit perfectly on the deck and offer the best compromise between weight, performance and flight time for freestyle.