  We report the status of R&D on large triple-GEM detectors for a forward
tracker (FT) in an experiment at a future Electron Ion Collider (EIC) that will
improve our understanding of QCD. We have designed a detector prototype
specifically targeted for the EIC-FT, which has a trapezoidal shape with 30.1
degrees opening angle. We are investigating different detector assembly
techniques and signal readout technologies, but have designed a common GEM foil
to minimize NRE cost for foil production. The assembly techniques comprise
either a purely mechanical method including foil stretching as pioneered by CMS
but with certain modifications, or gluing foils to frames that are then
assembled mechanically, or gluing foils to frames that are then glued together.
The first two assembly techniques allow for re-opening chambers so that a GEM
foil can be replaced if it is damaged. For readout technologies, we are
pursuing a cost-effective one-dimensional readout with wide zigzag strips that
maintains reasonable spatial resolution, as well two-dimensional readouts - one
with stereo-angle (u-v) strips and another with r-phi strips. In addition, we
aim at an overall low-mass detector design to facilitate good energy resolution
for electrons scattered at low momenta. We present design for GEM foils and
other detector parts, which we plan to entirely acquire from U.S. companies.
