Hitec Flash 4 SX Radio Transmitter unlocked.

The Hitec Flash 4 SX transmitter is actually a stripped down version of the Flash 5 SX, which is a more advanced computer radio with extra functions. The Flash 5 SX got an additional channel, the 5th channel which can be used for landing gear retraction and extension, flaperon and spoileron function. The transformation of the Flash 4 SX into Flash 5 SX can be done only by adding a few switches(which the Flash 5 SX have), a few resistors and doing some pin programming(by adding or removing jumpers or resistors). Both transmitters share the same processor.

Hitec Flash 4 SX, 4 channels for basic functions like the elevator, rudder, aileron and throttle.

There is only 1 switch on the Flash 4 SX

Remove the resistors circled in red. These resistors inhibits channel 5 and tells the processor that this model is a Flash 4 SX, so there are only 4 channels.

Resistors removed, ground yourself by touching the chassis of a computer before working with delicate electronics. it's a pain in the a** removing surface mounted components as they are smaller than a grain of rice.

Nah, look at the size of the resistors, shaky hand while desoldering these componenets may render the transmitter useless as you might bridge a lot of contacts on the circuit board causing a short circuit.

Wire all the switches and resistors, 3 additional switches have been added.

Short the 2 contacts circled in red and power on your transmitter. Tada, it's a Flash 5 SX now, scroll through the menus, it's showing the same thing as described in the Flash 5 SX manual.

4 switches in total

Circuit diagram of the Flash 5 SX

Functions of the switches from left to right, namely switch 1, switch 2, switch 3 and switch 4:

Switch 1: Elevator dual rate. An aircraft needs less control surface deflection when it's travelling at high speed, so you can set the amount of deflection by flicking this switch in flight. Up position=less deflection. Down position=max deflection.

Switch 2: Trainer switch. I'm not using this function.

Switch 3: Up position=spoileron. Down position=flaperon. Center position=off. Flaperon works well on my plane. I managed to land my plane at a very slow speed with flaperon deployed despite having a high wing loading on my plane. The high wing loading is due to the weight of the petrol engine used which is very heavy as compared to methanol powered engine. I'm astonished at the landing speed. Now I can call it an STOL, thanks to the flaperons. The spoileron does it's job pretty well too by slowing down the plane when im decending at a very steep glidepath.

Switch 4: Aileron dual rate.

Before using the flaperon function I tip stalled the aircraft during the landing phase where the ground to aircraft seperation was only 1 feet, even at high landing speed. Luckilly the main landing gear absorbed all the impact.

Wooden propeller

Bought a wood prop to replace the composite prop that I'm using currently, as the composite prop's diameter is a bit too small for my liking, I prefer more static thrust. The new wood prop got larger diameter and finer pitch as compared to the composite prop. Based on calculations, this prop should generate about 8.8kgs of thrust at 8000 rpm at sea level. That equates to a power to weight ratio of about 2:1.

Way cheaper than composite prop, Rm35 only. A composite prop with a similar profile and dimension costs about RM100. However wood prop won't last as long, it wears out faster.

Precautions

Hovering the edge 540 26cc, I think I need more practice and crashes to be able to do this. Look at how he lands the plane, it's simply phenomenal!