Linked below are some model research papers by high school and college students. Not all of them are as long as yours will be, nor do they all touch on the range of topics that you are writing about. Most of these emerged from pure research interests and do not have a project component, as most of yours do. Nevertheless, it will be helpful to look at these papers as the outcomes of the same kinds of research processes you are engaged in.
Effects of Food Deprivation on Concentration and Perseverance (APA; 12 pages)
The Origins of 20th Century Islamic Fundamentalism (Chicago; 30 pages)
Toward a Recovery of Nineteenth Century Farming Handbooks (MLA; 11 pages)
Adaptive Manipulation of Offspring Sex Ratio as a Means of Ameliorating Sexual Conflict in Drosophila Melanogaster (APA; 28 pages)
Developmental Psychology Paper (APA; 19 pages)
Lollard Bible Translation (Chicago; 17 pages)
Promoting Renewable Energy Generation in the United States (23 pages)
Music Education: Its Importance and Place in Today's Education System (APA; 24 pages)
Governance, Club Structure, and Spending Power in the German Bundesliga (Chicago; 24 pages)
For those of you who are going to El Salvador, you might also be interested in the work of these students. You won't be able to see all of these papers, but some are available, and you can see the titles and abstracts.
For more student research papers, visit these sites at Yale, University of Puget Sound, University of Michigan, Virginia Commonwealth University, Columbia (science or sustainable development), The Concord Review, W. W. Norton (publisher), and The Council on Undergraduate Research.
