Installation Manual ULPOWER UL390i UL390iS 390iSAMI 390A01 Revision No: 3 Date: 2014-09-15 Page: 68 of 69Propeller selectionPropeller with Rotational Moment of Inertia of up to 0.6kgm² has been used with no knownproblems up to date.An all wooden propeller is recommended to absorb engine vibrations. However a few compositepropellers have been used with no known problems up to date. WARNING : Never use the engine without a propeller. Damage will occur in this state.In case of using a ‘constant speed propeller”, only an electrically commanded propeller can beused. ULPower can optionally deliver a bracket to mount the electrical contacts.Part n° E022007Install the bracket as show in the picture. Starting from these you have to build up another bracketaccording to your propeller and the electrical contacts.