The illustration was taken from the Wikipedia page;
The main envelope was constructed first from 'blue' foam which was cut to profile and then plan. I then carved the rough shape with a modelling knife and sanded the shape with medium and rough sandpaper.
I was not to fussed about a final finish as working with 'blue' foam it is very difficult to get a smooth finish.
I then painted the envelope with PVA glue and white acrylic paint, sanded smooth and repeated the actions about six times, before painting with white acrylic paint and Klear (Future in the US)
The rest of the construction can be seen in these photos;
In truth, once the envelope was constructed the rest of the model was very easy, the only hiccup was the attachment of the small window bars to the bottom of the envelope
Painting is moving on apace - and here are a some work-in-progress shots;
There is still work to be done, but these photos show the model nearly finished, I hope that you like them