<<In reviewing the WOT performance curves for O-360-A, I note that they
converge to 0 power at 59,000 ft. This would equate to around 0.24 inHg at 0
C.>>

An interesting observation.

Verrrrry Interrrrrresting!

 

At 59000 feet, probably through the Tropopause and near or into the Stratosphere, I calculate about 2"Hg (Standard) and an OAT of about -50C.  BTW, how does 100LL interact with an ozone component?  Do I need an oil cooler there?  By Walter's power chart, 2500 RPM, 3-4" MAP is about 1% power.  As Gary said, perhaps over extrapolated.  How does a prop work up there? OK, I guess since B-29 was at 47000 in 1946 and Bohanon expects his blown RV to make it to 50000 (he maintains sea level power thru 25000). 

 

Grayhawk