Here is my build for May's Model of the month.
The Dragon M26A1,after many years of yeoman service,ending up downrange in Germany.



Birds like to rest on them,hence the white spots...



Many thanks to Airwarrior for ideas and a method of replicating rust.
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I'm no expert but looks a bit too shiny to me. The bird#$%@ was a great idea, but shouldn't it be with black little spots too. Would probably look more realistic. Also putting a pigeon or a few would hint to what those markings are. At first I could not figure out what they were until I read your description.

Looking good there Carl. I would add a little more variation in tone on the rust. Add a slightly lighter color on the middle of the panels, and patches of an orange color in places. Overall I do believe it is very good!

Konstantin:
black spots in the center or so of the "droppings" would be possible,I will have to find my 1 hair paint brush.
In sunlight it is very dull,but a flash tends to make the slightest thing shine.
Birds kind of know when to fly away from perching on a target tank,the hits from rounds tend to impress on their bird brains,what time of day is dangerous.

Dave,
having seen these 1:1 scale,this is the monotone of the rust,after a verylong time.When I make the dio base,I will spray up some kicked up dirt on the lower areas.And I have to "spill " a bit of model RR sand near some of the holes,these were filled with sand before being dragged out to the target area.