AERO RESEARCH’S photoreference CDs are absolute goldmines for whichever subject is featured, and this is notably the case with the Grumman S-2 Tracker, E-1 Tracer and C1 Trader. The 193 high-resolution colour and black and white shots of this classic ‘Ironworks’ design include military and civilian operators, and US and export airframes. At just USD $12.95 plus postage (USD $3.35 in the US, $12 overseas), this is a great-value package, regardless of which kit one has waiting to build. The majority of photographs are either sideon or front/rear three-quarter views, but for US Navy machines they highlight the variations in soft-edged demarcation between the Light Gull Gray uppers and white undersides, including wavy, scalloped and straight. Examples of Dutch, Japanese and Italian machines are supplied, while the civilian-owned aircraft add welcome colour highlights. More details are available at: