Using Arduino Uno to flash the Turnigy 9x transmitter with er9X

I used my Arduino Uno with ArduinoISP to change the software running in my Turnigy 9X transmitter. I replaced it with er9X, a firmware released under the GPL v2.0 license. The er9X firmware is an improvement over the stock one. You can find the instructions I followed at I also modified it so I can power it with one of my LiPo batteries. I'm mounting the battery to the outside until I get a battery that fits in the battery compartment.

3D printed Axial Fan Test Bench

Image 1: 3D printed air flow test bench. Measures RPM, flow rate, pump head and power.

3D printing EDF ducting for an axial fan test bench.

Photo: Warming up the Replicator 2 to 3D print some EDF ducting.

So I started 3D printed the ducting for the EDF test bench I've been working on. The plan is to generate some fan curves, and better understand the behaviour of the fans. I'll post more about the test bench soon.

85% fan area exhaust duct experiment

I started working on the design of a test bench for EDFs. I drew up an exhaust duct in ALibre, 3d printed it, and ran the fan. The duct has an outlet area of 85% of the fan area; as recommended by experienced aeromodellers for maximizing thrust. The fan used for this test is a 64 mm Haoye ducted fan I bought from Hobby King. The fan is coupled with a 3800 kV, 500W motor; also from Hobby king. Powering the unit is a 3 cell battery 15C 1700 mAh battery.

3D printed EDF rotor survives 20,000+ rpm

Figure 1: Side view of 3D printed EDF rotor. Reaction = 0.9, flow coefficient = 0.6, stage loading = 0.3.

Other turbomachinery library applications

Some potential RC applications for the turbomachinery design library:

- electric ducted fans
- aircraft propellers
- boat propellers
- jet boat propulsion

High reaction vs. low reaction compressor stage

Reaction is one of three non-dimensional numbers used to describe a compressor stage. It is defined as the enthalpy change over the rotor divided by the enthalpy change over the entire stage. Basically it expresses where the work done in moving the fluid is done: across the rotor or across the stator.

Figure 1: Low reaction compressor stage

Neat axial flow compressor video

This is just a neat video that talks about axial flow compressors.

I've been thinking, 3D printing isn't super precise and leads to unbalanced rotors. I have to figure out how to balance these blades, I find it difficult.

Blender Cookie - UI scripting tutorial

Learning more more about Blender scripting. Just sharing in case anyone is interested in learning Blender scripting. I'm a big Blender fan and have been using it for a good 5-6 years. Visit Blender Cookie, they have high quality Blender educational videos.

Ducted Fan Design Library using the BlenderAPI

I've just released my Blender Python scripts that parametrically generate the geometry for an EDF rotor. The scripts are in a very early, proof of concept state. They'll currently only generate the geometry for the rotor. WARNING: Manufacturing and use of the turbo-machinery designed with this software is at your own risk.


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