Contemporaries and Peers
Frank Costin [1920 -1995] and his Designs for Lotus
In this article we examine the work of Frank Costin and describe his work for Colin Chapman and Lotus.
Frank Costin made a significant contribution to Lotus at a time when the application of his scientific principles allied to Chapman’s chassis and suspension design helped compensate for the less powerful engines available to Lotus.
Frank Costin was a good applied engineer and extrapolated technologies in particular materials and aerodynamic principles from aircraft where he started his career. Its possible that some of his major designs might have been inspired by the Mosquito and Comet which was under development at the time when he worked for de Havilland.
“Applied aerodynamics is a combination of knowing physical laws, a great deal of experience and the right feel”
Frank Albert Costin was born on the 8th June 1920 in London. He was the first of four children .He was always very close to his brother Mike. In later life both brothers would be associated with Colin Chapman. [Mike would become famous for his partnership with Kith Duckworth forming Cosworth Engineering]
Frank had a “gift for acute observation, quick analysis and remarkable understanding”
Like Chapman he had a streak of non-conformity whilst aspiring to academic excellence. Frank preferred applied engineering where he could engage both hands and mind and have total responsibility.
From our analysis it will be evident that Costin’s ideas were extremely forward thinking particularly in the area of petrol / fuel efficiency extracted through aerodynamic design. His concepts and principles live on and in may respects have been copied or inspirational in many modern day city car designs.
Readers will also be aware of the significance of aerodynamics in current FI. Costin and Chapman were not the first but applied critical analysis and were committed protagonists.
Frank Costin possibly did not get all the credit he deserved. It’s hoped that this article will provide a perspective.
This article will be used as focus for a more detailed analysis of aerodynamic principles to follow.
Frank Costin: CV
Frank Costin was a gifted versatile engineer, thinker and industrial designer specialising in aerodynamics. He was also a cultivated man and competent musician and composer. As a young man he was a talented athlete [swimming] Like Chapman he enjoyed flying, gliding, sailing and with friends built a glider called Condor c 1949.His close friends included Ron Clear, Bert Parslow and Peter Davis. He started early working as an aircraft fitter but soon found promotion. By 1951 he was Flight Test Engineer [in charge of the Experimental Dept] at de Havilland and promoted in 1953 to Engineer in Charge [Aerodynamic Flight Test Dept; Chester]
His career included employment with:
Percival Aircraft Co.
Costin Drake [General Consultancy]
Family base consultancy towards the end of his life.
His design work included:
Costing-Nathan Group 6 Sports Racing Car c 1965 and GT coupe
Protos E2 single seater racing car with Brian Hart
Vanwall GP Racing car
Lister Jaguar sports racing car with Low drag body and space frame chassis
March 711 single seater racing car c 1971
Airport crash tender
4WD vehicle for JCB
TMC Costin sports car c 1983
Light weight aircraft and micro lights
Marcos GT c 1959 [world first wooden monococque]
Costin Amigo c 1968
The Ultimate Low Drag Vehicle
Maserati Le Mans Coupe c 1957
Costin Shopping Car
Costin Walker F4 [modular space frame c 1974 patent]
The Ultra Economy Car c 1975
Single Seater / mono road car
Costin Sports Roadster c 1990’s
Costin Designs Explained
The Marcos GT. 
This small sports car was the first to be built with laminated 1/8” marine plywood and spruce bonded with synthetic glue monococque chassis. The concept was inherently strong and comprised three torsion boxes running long ways and three across the car. These were linked together by he stressed floor. Also in wood were the boot and doors. It’s possible that it might have been partly inspired by the Mosquito aircraft of the Second World War. Strength and lightness were primary considerations.
Its believed the first prototype was registered DFF 529 and powered by an 1172cc Ford side valve engine. Costin designed the suspension based on Triumph Herald components. The coupe design incorporated a fixed roof and gull wing doors and by practical necessity a fairly crude windscreen and side screens. The overall weight is thought to between 8cwt- 9.75 cwt approximately.
Frank Costin joined in partnership with Jem Marsh [Speedex Castings and Accessories] and Peter and Dennis Adams to construct the car. Costin formed the Monocoque Chassis and Body Co and started assembly in North Wales.
The name Marcos was a derivative of surnames.
The Amigo 
This sports car was based on the plywood monococque chassis with glass fibre outer skin. The basic chassis was similar in principle to the Marcos GT. It is estimated the Amigo chassis weighed 187 lbs. The mechanical parts were from the Vauxhall VX 4/90 Victor or SL 1975 cc engine [96bhp -108 estimated]. As standard the engine was canted over which contributed to the low bonnet line.
The car as expected was very low and long [13’-7”x 5”-5” wide approx] and aerodynamic with a distinctive Kamm tail and flying buttress from the rear of the cabin. The windscreen was flush fitted .The efficiency of the body allowed performance figures of 130 mph, 0-60 in 7.2 seconds and 30mpg at 60mph approximately. The seats were of curved plywood.
The car was expensive. £3,326 in 1970. It had some very attractive practical features but also some significant drawbacks. It required development.
The Lotus Mk. VIII etc
A fundamental principle of aerodynamics is that there is a correlation between resistance speed and power. In the early Lotus trial cars with their low speed there was little requirement for drag reduction however this changed when circuit racing was entered.
When Chapman decided to compete in International level racing he realised that he would be forced into some practical concessions particularly around engine performance and that these would need compensation. To be successful both handling and aerodynamics would have to be superior to the opposition. Also the open wheel cars were prohibited by the regulations.
Great care in design and execution were required as streamlined bodies also increased weight and required additional breaking and cooling as a result of the additional speeds they achieved.
Mike Costin introduced his brother Frank to Colin Chapman c 1954 and they collaborated on the Lotus Mk.VIII.
Costin’s primary design objectives were:
Safety and stability at speed [driver safety/ protection]
Stable handling platform in roll. Yaw and pitch [see A&R article on Aerodynamic principles and terms]
Effective Centre of Pressure
Reverse camber line
Low frontal area
These were translated into detailed design and incorporated:
Very low nose for good air penetration
Twin tail fins
Fairings over rear wheels
Full length under tray
Metal tonneau over passenger side of cockpit
Small Perspex screen
Fully ducted radiator and brake cooling
Sophisticated parabolic curves and radii contouring of body [see A&R article on Williams and Pritchard]
The overall design was based around the major mechanical parameters, suspension movement etc. The completed body was 156” long x 55’wide x32 high at scuttle. The car weighted 10.25 cwt [approximately weights and measures]
Costin conducted scientific tests to compare the actual performance with his theoretical calculations. There are a series of photographs at disused aerodrome where the experiments were conducted. In one Costin strapped himself to the car to observe airflow.
The experiments involved a pressure head and additional readings were recorded on instruments comprising altimeters, air speed indicators and vertical speed indicators.
As a suggestion of the aerodynamic performance the editor quotes from a John Bolster road test. [Note the Mk.VIII was fitted with a M.G. 1467 cc engine equipped with Laystall alloy cylinder head. Estimated output of 85 bhp at 6200 rpm.]
Max speed: 121mph
Standing quarter mile =15.5 “
Estimated fuel consumption =30mpg.
The Mk.VIII had some defects and these were amended in the MK IX.  Costin made the body:
- Shorter overall length
- Altered tail fins to compensate
- Reshaped nose detail
- Drop down hinged doors
- Lower wrapped round Perspex screen
- Reduced drag and weight
- Length 142” width 56” height 27 ‘ at scuttle. Approximate. [Weight varied depending on engine]
At Le Mans the Mk.IX is believed to have reached approximately 130mph on the Mulsane straight. The Mk.IX was both a commercial and competition success. It used a variety of engines including he Coventry Climax and M.G.
Lotus Eleven 
The Eleven was a logical development of the Mk.VIII &IX. There was a new space frame and the swing axle was lowered.
Chapman insured the lowest and most practical frontal area was achieved by canting the Coventry climax engine over. This could be cared through to the scuttle.
Costin’s design for the Eleven included;
Dramatically smooth overall shape
Teardrop in pan [front to rear
Use of parabolic curves e.g. radiator opening
Reverse camber longitudinally for stability
Streamlined headlamp covers of Perspex
Partially enclosed wheels to reduce turbulence
Cockpit in elongated teardrop [plan view] with wrap around screen to prevent buffeting
More steeply swept nose and tail
Tailfins reduced to wings
Metal tonneau passenger side
Head fairing available on some models
Costin’s attention to detail also saw him invent the inflated air bag to act an alternative tonneau to prevent turbulence in the open cockpit.
The Monza World Record Car had further aerodynamic enhancements including a totally enclosed canopy over the cockpit and special attention to panel joints.
The Autocar Road Test of Nov.1956 recorded the following data [1100cc engine]
Max speed: 111.75mph
0-60mph: 10.9 sec
Standing quarter mile: 17.9”
Overall fuel consumption 47.8mpg. Kerb weight 9.1cwt approx
Wheel base 7’-1”
Front track: 3’-10. 5”
Rear track: 11’-2”
Overall width: 5’-00”
Le Mans speeds at Mulsane:
The Lotus Elite 
The Elite was born as Chapman’s attempt to enter a new league of production sports car. This was probably driven by considerations of financial security, cash flow for the GP racing programme, a response to a new 1300 CT category of racing and a genuine desire to evolve into a more sophisticated and advanced car production.
Chapman set the main parameters and criteria; mechanical specification and suspension.
The body design resulted from an interchange of ideas and practicality between Chapman, Frayling, Cambridge, Hickman and Kirwan-Taylor. Significantly and ambitiously the chassis and body were to be monocque construction.
Aerodynamic refinements that Costin introduced were probably more considerable than admitted and included:
A reverse camber line “ invisible centre line”
Refined front end nose detail to improve penetration
Refined wing line
Side screen flush with posts
Insistence on continuous under tray
There is some evidence that Costin suggested the partial Kamm tail.
On completion Costin projected that the Elite’s CD would be near 0.30.In 1962 at MIRA it was measured at 0.336
The Elite was an aesthetic masterpiece.
Approx: Weights and measures:
Weight: 1484 lbs
Flying on Four Wheels
Patrick Stephens 1986
WH Smith/ Sutton Publishing 2003
Picture courtesy of Motorbase