On Jul 8, 2:45 pm, Gig 601Xl Builder
wrote:

Treat it as you would any other business deal. Run the numbers. Since
you trust the guy running you can probably trust the estimated number of
hours he gives you for hour/month. Keep in mind though that the price of
fuel will have a direct effect on the number of hours the plane will be
rented.

I can't speak to the 152 directly, but we used to run 150s and
their poor performance plus the fact that the O-200 often needed upper
cylinder work halfway to TBO (and sometimes more often) meant that
they cost us as much to operate as the 172s. The student spent most of
his time climbing, either in the circuit or during upper air work, and
didn't get through the syllabus as quickly. More hours means more
money he has to spend, not good value for the student, so we let them
go and I don't miss them.
We did look into replacing them with 152s, but my research
indicated (Aviation Consumer and so forth) that they had plenty of
issues with their 24-volt system, not least of which was poor battery
life due to heat and vibration, and those batteries cost three or four
times as much as a 25AH 12-volt battery. The only advantage I could
find was the 2400-hour TBO on the O-235, but we have a Citabria 7ECA
with one of those and it suffers corrosion problems in the cylinders
because it runs too cold, and I've heard the same thing about that
engine in other airplanes. The corrosion causes pitting in the
cylinders, and the rings wear the cylinders faster as they run over
those pits, so that a sharp ridge is formed at the bottom of the ring
travel that starts shaving the aluminum piston pin plugs. More
teardowns and repairs and downtime halfway to TBO. Add to that the
solid lifters (the O-235 is the only Lyc with them) that need checking
every 100 hours, meaning that baffling has to be pulled off and the
rocker covers removed, more time and money, and any savings over a 172
disappears.
Lots of stuff to consider. It's worth noting that Cessna
didn't bother building them anymore. Not many people interested, I
think.

Dan