Hi Guys, thanks for the answers so far. I looked in the POH in the Cruise Performance section. Fig 5-7 indicates that 8000ft is the highest the engine can still produce 75%.
It becomes 68% at 10k and then 62% at 12k.
So it looks as if 8000ft is the optimum cruise level for those Cessnas….The TAS increases from 101 kts to 107 kts.
https://www.cpaviation.com/images/do...sna%20152.pdf.
I was thinking it had something to do with the L/D ratio remaining constant whilst the !AS- TAS improved. It does now look as if the engine's performance is the limiting factor.
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