If you create a text field formatted for time, when the prototype runs on an iPhone, the built-in time picker pops up. The time picker can be modified using javascript, but not being a developer, I was not able to get it to do what I want. So this functionality, which picks a number of hours and quarter hours, was not implemented. Instead, when you tap on an hours text box, a modified image of a time picker pops up. Tapping on the image dismisses it, and enters 11.25 hours in the text box. A long day for sure, but accurate, at least for this weekend project.