Diatone GT R249 F7

By Rebelution Nova on Nov 17, 2019

10  482  2

Introduction
While everyone is Jumping on the Micro Band Wagon, I decided to build a 3S-4S powered micro quad. Most of the micro quads are pretty generic. They maybe fast, some are strong, hell even some are extreme in their quality of the build. The issue is money. Most of the industry is changing and profits mean more than quality. I am not apposed to them making money, but the money made is lacking in real innovation, quality, and correctness for the purpose.

Goal and Parts Selection
The goal of this Micro freestyle build is to make a reliable 3S-4S powered rig with a high KV motor, long freestyle flight time with excellent flight characteristics.

Weight Reduction
I've used the following method below for shaving weight off the typical micro Build:

Micro FPV Cam over Full-sized FPV Cam
TBS Crossfire NanoRx instead of the Frsky
TBS Unify Pro V3
TBS Micro receiver antenna
I minimized the use of zip ties and shortened wires to the appropriate working length.
I Used the Tattu 450mah Lipo, It's by far the lightest 3S and 4S batteries made to date of this size.
1206 Xing Motors instead of 1105 Mamba motors for more torque and throttle response.

Reliability
I installed a TBS Triumph Pro micro antenna for range and strength
Custom TPU antenna mount
TBS NanoRx for range
RunCam Swift for quality in all lighting
Mamba F722 mini flight controller stack for speed, options, future proof, and capable of 6S at 30 amps for plenty of head room in the electronics.
35v 330ul Panasonic capacitor for clean video and clean power to electrical components
1940 Gemfan Hulkie Props
Standard buzzer to help find
Custom CLI programing in BetaFlight to have a specific tune and throttle used automatically selected based on cell count (total voltage) of battery used.
Props out rotation for handling

The AUW is 138 grams with a 3S Tattu 450ma battery
The AUW is 150 grams with a 4s Tattu 450ma battery

Results
With a 150g AUW, heaps of power, crystal clear FPV feed, and Betaflight 4.1 firmware, this freestyle quad is incredibly smooth and responsive. The build feels locked in and predictable from my initial flights as a newbie. The Swift is a fantastic FPV cam and allows for many adjustments. And finally, the XING 1206 6500KV motors are highly responsive and efficient throughout the rpm band. The native ability of 3S is very fast at 60mph and with a small throttle limit (automatically selected by voltage in BF), the 4S tune hits 70mph. The F722 FC allows it to be very versatile with a lot of processing power and 32-bit action. The GT R249 F7 has awesome range, clean video feed, the receiver goes forever, and the 306 ESC's can handle way more than the quad could ask for. The electroplated body and prop combination allows the GT R249 F7 to be seen easily and it looks great. Although it is very flyable and fast with a 4s 450mah battery, I would suggest a 650mah battery for longer flight times and killer freestyle freedom in the air.

Edit (4/18/2020)
I have made a new TPU mount based of the original custom mount to house a AXII Micro LHCP antenna. It achieves a greater distance and saves a couple grams of weight. No throttle limit is needed with a 4s battery while using proper BF 4.1 tuning. No official speed rating yet without a throttle limit, but the Hulkie props makes it known that it's cruising. LOL

Must Do Mods
These settings/Mods must be made or you will smoke the motors on 4s. Once the mods are made it flies very smooth and the motors are cool to the touch. Also to note no throttle limit is need when using these mods.

Blheli32:
Upgrade ESC's to 32.7
48khz
Demag- off
Motor Timing- Auto

Betaflight 4.1:
Target- Mambe F722 4.1.5
Dshot- 300
Biderectional- On
Pid Loop- 4k/ 4k
RPM Filter- On

Propeller Tip Speed Calculator
Prop Diameter: 1.9 In inches.
Engine Rpm: 96200 (88% Max rev)
Prop Speed: 96200 RPM
Prop Tip Speed: 544Mph 798Fps (MPH to feet per second, multiply by 1.4667)
Outside Temp: 20 Celsius ( Normal is 20 Celsius. )
Speed of Sound: 767 Mph. Calculated using Outside Temperature entered in Celsius.
Actual Prop Tip Speed: .71 Mach.

Theoretical Top Speed
Max Battery Voltage: 16.8
88% (14.8v) motor efficiency (96200rpm)
Aircraft drag: .20 for PPG.
Speed in Km: 117
Speed in Mph: 73
Speed in Knot: 63

Future
Maybe add some LEDs and try 2040 props

Photos

Part List

Frame

2019 GT-R 239/249/249+/349 inch Frame Kit (2 builds)
Diatone.us
$4.99

Flight Controller

MAMBA F722 MINI MK2 STACK
Diatone.us
$79.99

Motors

4 x iFlight XING Nano X1206 6500Kv Micro Motor
Racedayquads.com
$63.96

Propellers

4 Pairs Gemfan Hulkie 1940 1.9x4.0 PC 3-blade Propeller CW CCW for 1104-1105 Motor FPV RC Drone (9 builds)
Banggood.com
$3.19

FPV Camera

RunCam Swift 2 Micro - 2.3mm Lens (289 builds)
Getfpv.com
$26.99

FPV Transmitter

TBS Unify Pro 5G8 V3 (SMA) (167 builds)
Getfpv.com
$39.99

FPV Transmitter

TBS Unify-5V Filter Board
Diatone.us
$2.49

Antenna

TBS Triumph Pro (SMA) (7 builds)
Team-blacksheep.com
$19.95

Receiver

TBS Crossfire Nano RX - FPV Long Range Drone Receiver (649 builds)
Team-blacksheep.com
$24.95

Batteries

Tattu 14.8V 4S 450mAh 75C LiPo Micro Battery Battery - XT30 (21 builds)
Racedayquads.com
$10.11

Hardware

DIATONE General Screws Pack
Diatone.us
$2.49
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Discussion

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lorenzo220580   Nov 19, 2019  
1

very nice

Rebelution Nova   Nov 19, 2019 

Thank you

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