Conversion of Lansbergen Delta II to fly on 18mm motors. The particular Delta II that I chose to model was Delta 7920-8 247, launcher of the solar observation satellite ACE. The plans are available on the Caltech web site . Modifications: The model is a 10 page PDF file. I printed the 3 pages of instructions on regular paper, the 3 sheets of boosters was printed on 65lb cardstock, ...