I've wanted to post some case-studies of some "aero-modded" vehicles for the benefit of members and lurkers whom don't have access to some of the technical press.
The M-B 111/III knocked my socks off when I read about it, and I was still very impressed with the car when I got to see it first-hand at the Mercedes-Benz museum in 1997.
I can't format the material with tabs,'n such,so please forgive me for the "randomness" of the material.---------------------------------
| The car | Mercedes-Benz 111/III |
| Height | 1,029mm(41.16 inches) |
| Width | 1,688mm(67.5 inches) |
| Length(competition) | 4,784mm(191.36 inches) |
| Curb Weight | 1,347 kg(2,965 pounds) |
| Power | 171.58 kW(230-hp) |
| Final Drive | 1.65:1 |
| Engine | 5-cyl TD with intercooler |
| Chassis | all-composite,fiberglass and carbon-fiber |
| Cd(competition) | 0.195 |
| Roof slope @ tail | 11.5-degrees(my measurement) |
| Maximum cross-sectional area location | 2,589mm(103.56 inches from nose) |
| Fineness-Ratio | 4.64:1 |
| Truncated Boat-Tail Length | 700mm(28 inches) |
| . | . |
| PERFORMANCE | . |
| Top Speed @ Nardo Test-Track,Italy | 315.157 km/h(195.398MPH)-continuous 24-hour driving. |
| Fuel Economy | 6.26 km/l(14.7mpg) @ 195.398 mph |
Development of the car included an investigation of a full boat-tail,which added 1500mm length to car and dropped drag to Cd0.178.
A compromise was set at 700mm,which reduced the cars "base-drag" of Cd0.2378 down to Cd0.195 (a 18% drag reduction)
The full boat-tail reduced drag of the base car by 25%.
In full-tail form,the C-111 has a fineness ratio of 6.106:1,which in free-stream,above ground-effect would equate to 3:1,near the ideal teardrop.
Reference: CAR and DRIVER,September,1978,also Dr.Hans Liebold,Research Engineer,M-B,Report,as cited in Hucho,page 142,2nd edition.