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Frank! I have never flown around with someone with
another 235, so I have nothing for comparison. I have flown alongside Klaus
several times and he and I had the same IAS/TAS on our systems, with him, of
course, throttled back to stay with me. I have a well calibrated pitot and
static. I've done many two-way runs using my autopilot and altitude hold to
calibrate them vs GPS groundspeed; TAS always comes out within 1 MPH of GPS GS
avg. My two OATs are also mounted out of the airstream, so they show no
stagnation rise and I get correct dalt and TAS. My O-235 has 9.7:1 pistons, and
I get about 125 hp. I get 214 mph TAS at 1000' dalt, 2950 rpm, 206 mph TAS
at 8000' dalt, and 198 mph TAS at 2750 rpm, 14,500 dalt, 5.7 gph, all
when leaned for best power. I designed the prop to give 200 mph TAS at
2800 rpm, 10,000' dalt; I actually get about 201 mph TAS. ROC at 1000' dalt,
2430 rpm, 110 mph IAS, 1350 lb is 1500-1550 ft/min. My induction system
gives me the correct pressure recovery, which is total pressure minus carb drop.
Lycoming charts for the MA-3A shows the carb drop to be 1.1" at 12,500
pressure altitude. I have 43 gallons total, so I can get 1250-1300
miles with reserves, no wind, at altitude. I adjust my flap reflex angle to give
me the best speed. Varying it can change speed 3 mph or more from max (8 deg)
reflex when at higher altitude and higher weight. My wing-tip
additions increase my span to 25.2', area to 77.5 sq ft, and AR to
8.17:1.
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