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Project Notes

#578 Hawker Typhoon

Building the Airfix 1:72 Hawker Typhoon Mk.Ib, electrifying it with an engine and rocket effects and displaying it with a ground attack vignette.

Build

Here’s a quick demo..

clip

Notes

The Hawker Typhoon was originally intended as a replacement for the Hawker Hurricane (which didn’t really pan out), but it later became one of the Second World War’s most successful ground-attack aircraft.

After electrifying a Harrier GR.1 in LEAP#558, I was inspired to try some more tricks to pack in some electronics into a 1:72 scale aircraft. One of the first ideas that came to mind was to try and reproduce the iconic image of a Typhoon on ground attack with rockets over Europe.

I picked up the Medium Starter Set - Hawker Typhoon Mk.Ib A55208 from local supplier Hobby Bounties and have been slowly working away over a couple of months.

The end result:

  • Hawker Typoon with motorized propeller
  • rocket trails with LED effects
  • a diorama base showing the plane on low altitude attack over generic countryside

What follows are my notes from the build, including full schematics…

Typhoon Kit Build

A55208_kit

Hawker Typhoon Mk.Ib A55208 kit from Airfix is a new tool (2013) and packaged as a starter set with Humbrol paints, brushes and glue.

Engine Installation

The kit is designed to have a free spinning propeller, but I don’t think particularly designed to have an electric motor installed. There is ample room however, and I installed a 6.5 x 8mm micro DC Motor rated for 1.5V 0.005A and 20000RPM. This was from my stash of parts - but originally purchased from aliexpress.

Installing the motor means changing the sequence of assembly slightly, and also solving a few problems:

  • mounting the engine securely - I wrapped the motor in masking tape to the required dimensions to fit in the fuselage and glued in place. This provides a secure yet dampened, somewhat flexible mounting
  • connecting to the propeller - this was the biggest challenge, as any misalignment will either overload the motor or prevent the propeller from spinning at all.

Note the reverse protection diode mounted close to the engine on a small piece of protoboard. Also important to get the polarity for the motor correct so the propeller doesn’t spin backwards!

build_01_engine_installed

Test, test, test! Before taking any irreversible steps forward in the build.

Here I’m testing the motor with a 3V 555 timer PWM circuit. Yes, it is working!

build_02_engine_test

With the lower wing installed, motor control wires exit near the rocket pylons:

build_03_lower_wing

Painting the Typhoon

I’m brush painting the kit with mainly the Humbrol paints supplied in the kit. Getting a reasonable finish takes many layers of thinned paint, but it’s hard to get a solid coverage without having the paint end up quite thick. PS: I now have an airbrush, so I think this may be the last time I brush paint larger surfaces!

Colour Paint Notes
Dark Green Humbrol 30  
Black Humbrol 33  
Aluminium Humbrol 56  
Light Grey Humbrol 64  
Cockpit Green Humbrol 78  
Ocean Grey Humbrol 106  
skin tone ad-hoc blend of art acrylics pilot skin
Lemon Yellow Vallejo 70.952 propeller tips and control box

Here are some shots before weathering and final assembly. Note that only 6 out of 8 rockets attached. Two will be in-flight!

After painting, the plane was finished with Mr Hobby Flat Matt Topcoat.

build_04_plane_paint_upper

build_05_plane_paint_lower

Building the Vignette Base

The vignette base is an ad-hoc rendition of an imaginary field with a stone wall and stream. Construction basics:

Basic construction:

  • styrene foam base and structure
  • toilet paper + mod podge
  • plaster of paris for the wall rendering

Detailing:

  • Woodland Scenics earth foam
  • static grass
  • some dyed lichen for bushes
  • mod podge and gloss varnish for the stream (colours a bit off in the photo as it was still drying)

build_06_base

The rocket trails a BBQ sticks with LEDs and current-limiting resistor swathed in cotton wool and air-brished for highlights.

build_07_led_install

The backdrop is a quick hand-painted generic “cloudy sky”. This is from a trial assembly before everything is complete:

build_08_trial_fit

Final Assmbly

The motor control wires cut to length and terminated with pin headers. These plug into a socket embedded in the stardboard rocket tail. I’ve added some small stand-offs (actually through-hole compomenent wire trimmings) to the empty rocket pylon. These will allow the Typhoon to be positioned slightly above the rocket smoke trail.

build_09_plane_final_assembly

The external electronics are packed into a 100x60x25mm black plastic electronic project box. The cover was airbrushed lemon yellow with the Airfix kit identification decals attached, and finsihed with Mr Hobby Semi-gloss Premium Topcoat.

build_10_controller

The controller plugs into a wiring socket on the back of the backdrop:

build_11_rear_connections

The finished project is housed in a 30x20x20cm Acrylic Display Case:

build_12_case

Electronics

The electronics comprise:

  • 3V battery power supply with switch
  • RGB fast flashing 5mm LEDs with 100Ω current-limiting resistor
    • the RGB LEDs run a fast animation sequence
    • by having two in parallel for each rocket, the effects are randomized somewhat
    • a better effect could probably be achieved with red fast flash LEDs or custom flashing circuitry but since I had some of these RGB fast flash LEDs on hand I went with those - the effect is not bad despite some of the colours not being that authentic
  • a simple high-side current control circuit for the motor with variable resistor for some degree of speed control. The current-control approach is smoother than PWM, however it does sacrifice torque at “lower speeds”.

Since the moter control is high-side, only 3 wires are needed to connect to the project: ground; LED power; motor power.

Breadboard

Schematic

Testing the circuit on a breadboard:

Breadboard Build

Some glamour shots of the final build:

Build hero3 hero4 hero5 hero6 hero7 hero8

And a demo video:

clip

Out and About

Added a project page on scalemates.

Credits and References

About LEAP#578 scale modelsCraftAudioLED
Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.