Hirobo SRB Quark SG

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Hirobo SRB Quark SG
Manufacturer Hirobo
Class Collective pitch electric
Build Kit,RTF
LevelIntermediate to Advanced


The Hirobo S.R.B Quark SG (aka Quark SG, Quark CP), is a micro-sized collective pitch electric helicopter manufactured by Hirobo Corporation. “S.R.B.” stands for Single Rotation Blade to distinguish it from Hirobo’s coaxial “X.R.B.” helicopters. “SG” stands for second generation that follows the original Quark which is a fixed pitch electric helicopter. The Quark SG was announced around February 6, 2010 at the Nuremberg International Toy Fair and was released for sale in April 2010.


  • Gear Ratio: 5.29:1 (Main Blade)
  • Length: 361 mm
  • Height: 146 mm
  • Width: 72.5 mm
  • Main Rotor Diameter: 373 mm
  • Tail Rotor Diameter: 106 mm
  • All Up Weight: 200 g

“Second generation” features

  • CP head and mild 3D flight capable.
  • The Quark SG is capable of loop, roll and inverted flight.
  • Flybar moved below the main blades.
  • Gyro mounted on the back of the helicopter which avoids effects from heat.
  • Status light moved to the rear of the heli for increased visibility.
  • Blades are harder for handling aerobatic flight.
  • 3 cell (11.1V 480mAh) battery.

Stability features

Flight stability is a result of a combination of design features that includes:

Safety & damage resistance

Safety features of the Quark make use of polystyrene (Styrofoam) blades (semi-symmetrical airfoil), and a flybar with rubber paddles. In a crash, the blades are meant to break which helps to absorb impact and prevents damage to other components.


The helicopter uses a brushless main motor and a direct drive brushless tail motor. Both are outrunner. The main motor is the same as the Quark SRB 1st gen, but just runs at a higher voltage (3 cell lipo instead of 2 cell)

Lipo battery

A 3-cell 480mAhLipo. The stock battery is reported to yield a flight time of 10 minutes.


  • 40MHz or 72MHz FM-PPM RX (Futaba, JR, Aitronics/Sanwa compatible)
  • Hirobo stock 4ch TX for XRB or SRB FP is usable only with normal mode.
  • 3 versions available: assembly kit, RTF, RTF with transmitter.

Kit contents

assembly kit:

  • main frame, head and tail parts
  • canopy (cabin)
  • landing skid
  • horizontal stabilizer and tail fin
  • battery holder
  • SRB control unit with gyro sensor and LED lamp
  • 3 SRB servos
  • 4 sets (8 pieces) of main rotor blade
  • 4 one-piece tail rotor blades
  • 3S480mAh Li-Poly battery
  • charger with AC adapter
  • blade balancer
  • extra screws
  • +screw driver, plastic - driver, hex Allen wrenches 0.89mm, 1.5mm
  • decal
  • instruction manual
  • registration card

receiver crystal is not included.


  • MSRP 58,000JPY or about $650 USD as of February 2010.
  • Street price of approximately $725 - $800 USD as of December 2010.

Hirobo upgrades

The following high performance parts ("High precision CNC cut parts, blue anodized") were expected to be released by Hirobo in October 2010:

  • SG-EX blade holder: "Additional hole for more tuning options. More pitch stroke."
  • SG-EX seesaw: "Additional hole for more tuning options. More pitch stroke."
  • SG-EX mixing arm: "More precise control with rigid parts. Bearing used instead of collars. Additional mounting hole on outside."
  • SG-EX washout control arm: "More precise control with rigid parts. Bearing used instead of collars."
  • SG-EX slide block: "More precise control with rigid parts."
  • SG-EX swashplate: "More precise control with rigid parts."
  • SG-EX main motor: "20% more power compared with stock parts."

Other upgrades

Aftermarket upgrades from other vendors include:

Known issues/shortcomings

Design/Manufacturing items

  • The tail motor may spin too slowly at very low throttle causing the heli to spin on the ground. Pilots may have to bring up the throttle quickly from start and/or try several times for the tail motor to engage at the correct speed.
  • Foam blades are fragile and break easily. It is for safety and to protect the head mechanism in case of crush.

Flight issues

  • Requires significant right aileron trim in idle-up for hover. This issue can be overcome but requires the use of a programmable radio that has different trims for normal and idle-up modes.

Radio system issues

  • No modern 2.4 GHz system except for 3rd party conversion (see above).

Hirobo eccentricities



Flying aircraft is a dangerous activity and can cause injury or even death. Follow all safety procedures as outlined in the manual and local regulations.

Tips for the beginner

General tips

Trivia/interesting tidbits/rumours etc.

  • A Quark with collective pitch (CP) was rumoured in August 2009 for release in late 2009 but was formally announced as the at the Nurnberg International Toy Fair, around February 6, 2010. The assembly kit was released March 31, 2010 in Japan.


"Flies like it was on rails...", gratefulfrog, October 21, 2010.

"If I thought the FP Quark was an 8/10, then the SG has to rate at least an 11/10 in comparison. And I haven't even moved up to Sport Flying yet! Not to say I'll never buy another helicopter, but this has the potential to be the only one I'll ever need.", Harv, June 12, 2010.


Links to selected quark videos

Nice 3D Quark SG Video [1]

External links

Hirobo Quark official website

Main discussion forums


Mods and repairs


Parts and product support

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