I did the sums, and a spreadsheet, but that was a long time ago.
The numbers are a guess on both sides of the equation - rental prices can go up and down, and maintenance on an owned aeroplane is a highly variable feast.
We used "most probable" numbers, which have proved reasonably accurate over the past 9 years. For an Arrow III, we found that a sixth share breaks even compared with hiring a club Archer if you fly 23 hours a year.
BUT: if you own a share,
- you get to fly a nicer aeroplane;
- the next hour costs a lot less;
- you can be pretty confident the previous pilot looked after it properly.