Hello,
Wanted to share a normally aspirated Cessna 182’s altitude performances.
Climb is done with constant EGT method (Max RPM = 2400)
Cruise is set at PEAK-EGT (RPM = 2200)
In cruise, IAS is between 100 and 105.
It would have climbed, with patience, to FL175 quite easily. I would have expected IAS between 90 and 95 IAS in cruise there.
For complete information, we took off two on board, two bikes, luggage, full fuel, i.e. 80kg below MTOW.
On the return flight, lighter (we did not refuel), same FL, speed was pretty the same, so the mass is not a huge factor.
I also fly a newer 182 non turbo and although I find better fuel savings at altitudes, but substantial loss of airspeed due to low manifold pressures..
If weather is not a factor, FL 75/85 works the best for NA 182’s
Or IFR routing making it mandatory.
We were flying from LFMA to LIPR, and the airway requests FL150 near Nice.
Otherwise, I would have had to fly to Corse before :-) (or at least to file, maybe not to fly)
Dealing with best cruising altitude, I am reaching, more or less, the same TAS range between FL70 and FL120: circa 140kt.
Difference is fuel economy and oxygen supply need of course.
Dealing with best cruising altitude, I am reaching, more or less, the same TAS range between FL70 and FL120: circa 140kt.
That is about right for the TB20 too (250HP IO540-C4). I’d say the TAS is held to FL160+. After that one has to go to “best power”, i.e. ~100-130F ROP, eventually reaching the ceiling which by definition is at best power.
Due to second order factors the best MPG is achieved c. FL100-120 and LOP, and 2200rpm.
On nice days I level off at FL100.
No free lunch in GA; most planes are the same 
I flew a G1000 182T from Dallas to Paris a few years back was indeed impressed with it’s performance at altitude.
IIRC, I averaged about 10.5Gal/H @ 140K TAS generally around FL100 .
With that I had enough range to do the trip without a ferry tank !
Peter wrote:
Due to second order factors the best MPG is achieved c. FL100-120 and LOP, and 2200rpm.
That’s with a FAT & “slow” wing.
As an example, the natural laminar flow wing design on my Lancair / Columbia is at it’s best (in terms of fuel efficiency) when flown @ 140K Indicated.
If I fall below this, the incidence of the wing goes up and of course induced drag increases, so the airspeed drops off dramatically.
