Hi Andy,
A semi cantilever wing is the type of wing fitted to small Cessna a/c, as well as some others e.g. Shorts 330/360.
This is where part of the loads placed on the wing are channelled into the structure via a strut. This triangular structure is theoretically incapable of bending. In practice, the strut will flex somewhat under the imposed loads. Remember that in this case the strut is a tension member as opposed to being compressed.
On the C152 the strut disappears into an aerodynamic fairing. I guess it must be bolted on or held with a pin. It consists of the actual structural member with an aerodynamic cover over the top.
At the wing root, the wing might be simply bolted on or it may be held on with interference fit pins. This method sometimes relies on cooling down the pins with liquid Nitrogen or similar. The pin is driven home and warms up in the ambient temperatures, expanding and producing a very tight fit.
Somebody help me out here?!
Look at the case of the Cessna 177. This aircraft was designed to replace the C172 over thirty years ago. We can all see what happened there! The Cardinal has a pure cantilever wing with no struts, which improves fuel economy, gives increased speed and greater range etc. Without the struts, the wing has to be stiffer and heavier in order to withstand the same flight loads.
http://www.flyer.co.uk/cardinal.php
Also see Airframe Structural Design by Michael C.Y. Niu
Hope I’ve helped.
Noisy