If you look on the various UK websites that sell shares in aeroplanes, you'll see numerous not-for-profit syndicates there with an advert saying something like:
"1/8th share for sale, Cessna 172, £60/month, £85/hr wet" (I just made those numbers up).
Those adverts will tell you very accurately the real cost of operating these aeroplanes. In this case, what it tells you is that the fixed cost of owning that C172 is about 12 months x 8 owners x £60 = £5,760
And that the variable cost for a low useage aeroplane is £60/hr.
So if it flies 100 hrs per year, you can work out the hourly cost as £60+£57.50 = £117.50.
And so on.
You can go thorugh several adverts for shares on each of the types you're interested in, adjust for your local conditions (especially fuel price), predicted number of flying hours per year and you'll get some pretty accurate results.
Look up hangarage prices, and the cost of fuel in various places, put it in a spreadsheet, along with looking at the effects of high and low utilisation and you'll start to get answers that you can justify and thus will give you good marks in your student assignment, which responses purely from an internet bulletin board won't do. Even one as good as Pprune.
G