Radically new technologies, of which ‘the functionality was new to the market or the price-performance ratio was much better than contemporary products’ (Ortt, 2012), can be both risky and rewarding to develop. The innovation phase is the period from invention of a radically new technology until the first market introduction. This research into the first phase develops a model that provides guidance during the innovation phase. The main research question is: How can important factors that help or hinder the development of radically new technologies during the innovation phase be modelled? A literature review, to understand the role of the innovation phase in innovation models, uses papers from several fields of research: S-curve, pattern of development and diffusion, conditions for large-scale diffusion, Strategic Niche Management, Minnesota Innovation Research Program, Fuzzy Front End, and Sectoral Systems of Innovation. A second literature review, to understand characteristics of the innovation phase, is performed, using the same fields of research as in the first literature review, but complemented with more applied research that provides even more empirical data through case studies. All topics of interest from both the innovation models in the first literature review and all claims in the second literature review, come together in the search of factors for the innovation phase. Two case studies are performed: 3D printing and Augmented Reality. Both case studies provide new insights and improvements to the list of factors. The centre of the model is formed by a group of five factors. Those five factors go from Expectations to Strategy to Resource to Knowledge to Product. The Innovator is the self-appointed process owner who wants to create the product. The Innovator tries to manage those five central factors to maximally improve the technology’s chances. There is a special role for Resources, because insufficient focus on this factor results in a complete stop of all development efforts. The four other factors all have influence on the five central factors. It is up to the Innovators to increase help to the five central factors and to decrease any problems. Examples are to use demonstrations to increase expectations or to secure funding, or to deal with a complete lack of demand for the technology, or with laws that prohibit the product from commercialization. An important limitation to the research is the hindsight bias in which the definition of a technology is based on what the technology eventually became. It is also hard to prove a model that is based on factors: the best option is to make it as plausible as possible. The most important recommendations are to add a measurement of the number of Innovators to the innovation phase of the pattern of development and diffusion, to explore the transition from the innovation phase to the market adaptation phase, and to formulate strategies for the innovation phase, based on this model and its factors.