I'm still playing around with the final composition, as it is possible to have as many as eight further Thunderbolts in the background behind the main pair. While I think it will be exciting to include so many aircraft I don't want the overall composition to be weakened, or over crowded.
In the meantime as a little light relief, and as an excuse to actually do some art I scribbled a quick value study down of one of the main pair.
This study is on tracing paper, which allowed me to overlay it over the already completed line drawing. This is the first time I have used this method, and it is obvious why it is recommended. However the quality of the tracing paper I had to hand is far lower than it needs to be. However as quick exercise it served it's purpose.