Several CWL /CZL propellers exhibited – most likely in 1921, place yet to be confirm.  Four different types of decals are represented with these propellers. Most airscrews are made of mixed wood, which can be typical for early stage of propeller building (for later version mostly ash plies were used).  The dark one with unknown coating. Two propellers with sheathing. Thanks to Robert Gretzyngier, who sent us this photo! (entry: 2022).