WordNet
n. a preliminary experiment whose outcome can lead to a more extensive experiment
Wikipedia
A pilot study, pilot project or pilot experiment is a small scale preliminary study conducted in order to evaluate feasibility, time, cost, adverse events, and effect size (statistical variability) in an attempt to predict an appropriate sample size and improve upon the study design prior to performance of a full-scale research project. Pilot studies, therefore, may not be appropriate for case studies.
Usage examples of "pilot experiment".
The buoys which were set adrift last year as a pilot experiment showed that the fastest drift speed we can expect from a buoy is about one knot.
The actual mating, to be sure, would be voluntary and legalized by marriage (at least in the pilot experiment): the whole operation would amount to no more than a sophisticated and programmatic Courtship Counseling, already in its simpler form a popular WESCAC service, and should tend towards improvements in the student body of a sort no right-minded person could object to: better physical and mental health, higher IQ's, intellectual earnestness, Enochian humility, and the like.