They had a swing-arm Mk3 prototype running about towards the end when BSA pulled the plug on Ariel 4 strokes. They really should have done that 5 years earlier with the mk2 however.
I must agree with you but maybe the decision makers at Ariel were thinking that most Squariel buyers were sidecar riders.Back then Plunger frames were rightly or wrongly considered the best suspension for Sidecar rigs. John
The concept was taken further again in later years by the Heeley brothers, with an Egli-type frame. A nice looking ride IMHO.
Another .. 1949, the first year for the S7 Deluxe. OHC engine and a cantilevered sprung (spring in the top frame tube) seat, luxury.