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Airspeed as fuel flow
As everything with Stick and Rudder, very interesting. I compared it to the USAF Dash 1 for the O-2A. Best glide is 100 kts at 4400 pounds. The performance charts say best long range airspeed is 104 Kts CAS and best glide is 99 kts at the same weight!
Similarly, at 4400 pounds, service ceiling is 17,500 ft. 2/3 of that is 12,000. By the book, at 12k max MP is about 17 to 17.5 which is the power you need to get ~104 kts CAS! (126 KTAS) Seems like 1944 rule of thumb calculations for SEL planes were still valid 25 years later for MEL!
I don't carry oxygen, but the dash 1 shows 110 kt CAS at 8,000 still gets me 124 KTAS at 8.2 gph/engine. That is just a little slower that 12k at 1/2 a gallon more per engine per hour. But I can breathe, which is a good thing.
But...20 minutes longer for a 300 nm trip vs my normal cruise at 65%.
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