Editing Water wheel (section)

=== Hydraulic wheel part reaction turbine ===
A parallel development is the hydraulic wheel/part reaction turbine that also incorporates a weir into the centre of the wheel but uses blades angled to the water flow.
The WICON-Stem Pressure Machine (SPM) exploits this flow.<ref>[http://www.oewatec.de Oewatec]</ref> Estimated efficiency 67%.

The [[University of Southampton]] School of Civil Engineering and the Environment in the UK has investigated both types of Hydraulic wheel machines and has estimated their hydraulic efficiency and suggested improvements, i.e. The Rotary Hydraulic Pressure Machine. (Estimated maximum efficiency 85%).<ref>[http://www.energy.soton.ac.uk/category/research/renew-energy/hydropower/ Low Head Hydro]</ref>

These type of water wheels have high efficiency at part loads / variable flows and can operate at very low heads, < {{Convert|1|m||abbr=on}}. Combined with direct drive Axial Flux Permanent Magnet Alternators and power electronics they offer a viable alternative for [[Low head hydro power|low head hydroelectric power]] generation.