I was talking with Matt in the chat a few days ago and again the Commander came up and it was said it was a high-drag aircraft. After that I looked at airliners.net and found some specs of other similar aircraft and some were slower but didn't seem to have a larger cabin and while some were ok fast they couldn't climb that fast compared to others. For a car you have have wheel-alignment, gear-ratios, engine torque-curve characteristics, tire-types/sizes that vary in rolling-resistance etc. that all influence acceleration, top speed and fuel-economy but what goes for an aircraft? Is it basically just the fuselage/wings that have a say or can a different prop give a significant difference in top-speed/fuel-efficiency? What about RG planes without wheel-covers like the Commander, would a plate over the wheels give anything, or removing the grip handle on the outside where you step up?
Here's a list of data for aircraft with 4 seats, retractable gear and around 200hp engines.
Edit: Hmm, for some reason, in the forum the tab-spaces aren't working unlike in the editor so the data isn't organized in coloumns but I hope you can read it all the same.
Aircraft Weight Power Max speed Initial Climb
Beech D35 Bonanza 760kg 205hp 306kph/165kt 1100ft/m
Cessna C177RG Cardinal 800kg 200hp 290kph/156kt 925ft/m
Money M-20E 714kg 200hp 317kph/171kt 1120ft/m
Piper PA-28R-201T Arrow 786kg 200hp 330kph/178kt 940ft/m
Rockwell Commander 112B 804kg 200hp 277kph/150kt 880ft/m
SIAI-Marchetti S-205-20 760kg 200hp 270kph/146kt 826ft/m
Socata ST-10 723kg 200hp 280kph/151kt 1005ft/m
I must say though, the Arrow seems unbelievably fast, any idea how come? I can't remember if it's turbocharged/normalized but when looking at the Commander data in the next paragraph then it could be the answer.
There was a new version made of the Commander in the 90s where they listed some aerodynamic improvements, a new engine cowl for one. However looking at the data between the original Rockwell GA-114A and the new Commander 114B there doesn't seem to be much difference, although that would depend on which of airliner.net's speeds are correct, the kph or the kts. If it is the kts then the improvements could perhaps make the Commander 112 faster than a C177RG. However how come the TC model with just 10 extra horsepower is so much faster? Is that because top-speed usually is achieved at well above sea-level where the turbo would help keep the engine-power?
Rockwell Commander 114A 885kg 260hp 307*kph/157kt 1088ft/m *) 157kts = 291 kph
Commander 114B 927kg 260hp 304kph/164kt 1070ft/m
Commander 114TC 1018kg 270hp 364kph/197kt 1050ft/m
During my research for these planes I also found a very special plane I hadn't seen before, a Ruschmeyer R90. Aerodynamically clean body made of glassfiber with Rohacell core, rain-tolerant laminar-flow wing, a 230hp flat-six (de-rated from 260hp) and a top-speed of 324kph / 175kts with an initial climb-rate of 1140 fp/m although 1650ft/m is listed as possible. Now here's the really interesting part, something I haven't seen on any other small GA plane before, a 4-bladed propeller.
http://www.airliners.net/photo/Ruschmeyer-R90-230RG/1369794/M/Frank