Notes to self: took at look at a used single seat CGS Hawk Arrow for sale (ad link). This one is registered as an ELSA (N4209F), powered by a Rotax 503 DCDI 50HP 2 stroke engine with electric start. The engine was rebuilt in 2004 and has about 50 hours on it. TBO for this engine is listed at 300 hours or 5 years, which ever comes first. It is a simple engine and could be rebuilt for parts cost (link) or by a rebuilder for considerably more. It has pretty complete VFR instruments, with a hand held radio, but no transponder, electric fuel pump in addition to mechanical fuel pump, an anti-collision strobe, full flaps and in flight elevator trim. The sails are probably towards the end of their useful life, replacement Dacron would be around $2,200 (link), but would probably go one or two more seasons. This would need to be tested. The machine has an almost complete set of vortex generators, but is missing a few and would probably need to be replaced or eliminated on sail replacement. The machine appears to be well built, but was involved in a minor mishap (2004), which is well documented. The current owner was unable to start the motor, probably the result of old pre-mix gas. Yes, this requires premix (oil/fuel) gas. But there may be other concerns, as the Rotax (and other 2-stroke engines) do want special care and feeding (there are courses). Links to non-ethanol gas stations in NC.
There are others Hawks for sale, even listed on one site, and there are a number of similar machines available at various prices, such as the Challenger, Rans S-12/S14 series, Quicksilver, Kolb (M3X), Flightstar, and others. Check out UFlyit for sales and courses.
CGS Hawk Service Bulletins.