Since this is a physical paper model kit from the 1990s, "RAR" files found online are often scans shared by hobbyists. Check these sources:
any downloaded file with antivirus software before opening. Download Fly Model 071 Avro Vulcan rar
specifically for "Fly Model 071 PDF" as it is a more common format than RAR. If you'd like, I can help you: Find physical copies currently for sale. Since this is a physical paper model kit