Walkera 4#3B micro RC helicopter

The Walkera 4#3B electric rc helicopter is a long-awaited fully functional radio controlled micro helicopter that sits comfortably in the palm of your hand, and brings indoor model helicopter flying to a whole new level!

Shop for the Walkera 4#3B on eBay.

The 4#3B follows on from the 4#3, the first 'affordable' conventional RTF micro rc helicopter, and is essentially a scaled-down version of Walkera's hugely popular Dragonfly 4 Fixed Pitch (FP) electric helicopter. While FP helicopters may not have the smoothness and agility of a Collective Pitch (CP) helicopter, they do give the pilot all the right feelings of proper model helicopter flying.

Indeed, it's fantastic news for the hobby that such micro helis have finally become so easily available, and it's thanks to manufacturers like Walkera that model helicopter flying has become so popular in recent years; traditionally rc helicopters have been both expensive and difficult to fly, but modern-day models are certainly rewriting the books.

Walkera 4#3B in detail

With a main rotor span of just 202mm and an overall length of 213mm, the 4#3B truly is a micro rc helicopter. A good size room gives you plenty of useable airspace for a helicopter this size, but if you're a newbie then don't be fooled in to thinking that it'll fly straight out the box for you. It's still a conventional helicopter and they are inherently difficult to fly at first, regardless of their size.
An advantage that the 4#3B has over its larger cousins, of course, is that its tiny spinning rotors won't do too much damage to whatever they come into contact with!

So if you've never flown a single rotor helicopter before, be warned! The Walkera 4#3B is very stable in experienced hands, but for the complete beginner it will seem virtually uncontrollable - it's absolutely no different to learning on a larger single rotor rc helicopter, it's just the nature of the beast.

4#3B alloy rotor head parts To improve on stability and durability over the original 4#3, Walkera have equipped the 4#3B with alloy parts in the rotor head assembly. CNC machined, they not only improve the helicopter's performance but also give it a great look.
The simplified 90 degree swashplate is connected to two sub-micro (3.5g) servos for left/right and fore/aft cyclic control operating the metal flybar.

Under the hood is a single 1220 motor which gets its power from a single cell (3.7V) 400mAh li-po battery which gives the helicopter around 8 to 10 minutes of flight time, after a 40 minute (or so) charge with the supplied wall charger.
In front of the motor is where it all happens - the 3-in-1 mixer unit plays host to receiver, main and tail motor speed control and gyro.

Above, mixer unit, motor and servos of the 4#3B

Shop for the Walkera 4#3B on eBay.

Flying the 4#3B

As stated earlier, learning to fly any single rotor rc helicopter is no easy task - only coaxial rc helicopters can be pretty much flown right out the box by a beginner.

But the Walkera 4#3B is very stable, and my previous experience with my trusty Dragonfly 4 meant that I could have a successful first flight. The helicopter needed no setting up whatsoever, everything was balanced to the point that there were no obvious vibrations at all.
The rc system supplied with the 4#3B is 2.4GHz technology, which cuts out the risk of unwanted and dangerous interference. Control response is very good, and the helicopter has ample power.

The only negative characteristic I found was that it does tend to 'wander' sometimes, when the pilot isn't paying full attention. This I put down to the weight of the 4#3B in relation to the amount of thrust coming off the tail rotor; right cyclic is definitely needed to maintain a steady hover without the helicopter being pushed over to the left by the tail rotor thrust (or maybe it's just my flying...).

Here's a short video of my Walkera 4#3B in action...

As you can see, the Walkera 4#3B can be safely flown in a small room. Trying to keep it in the camera's field of view is another story, however, but that's just my flying ability...

Below are some detail photos of the helicopter, click any image to view it larger:

Canopy	Main rotor blade
Servo, motor & mixer	Mixer unit & motor
Alloy rotor head	Cyclic servo
Li-po battery in place	Tail rotor & motor
WK-2401 transmitter	Wall charger

Walkera 4#3B features & specs

The official specifications are...

Main rotor diameter: 202 mm
Tail rotor diameter: 48 mm
Overall length: 213 mm
All-up weight: 48g (inc. battery)
Min motor: 1220(strong magnet)
Tail motor: N51 (strong magnet)
Battery: 3.7V 400mAh Li-Po
Transmitter: WK-2401
Receiver: RX-2406
Gyro: Built-in
Servo: weight 3.5g
speed 0.11sec/60o(4.8V
torque 0.30kg/cm(4.8V)
dimension 17.5mm x 6.5mm x 21.5mm

In summary, the Walkera 4#3B electric rc micro helicopter is an excellent product indeed. Being able to fly a model helicopter around the bedroom was a very unrealistic dream when I was a kid, but now it's an affordable reality! That's great news for the hobby of rc flying.
NB: Since this page was written, the 4#3B has been upgraded to a brushless motor, and there is a 3D version on the cards - where's it going to stop?!!

Shop for the Walkera 4#3B on eBay.

Micro rc helicopters - an overview of palm-size helicopters.