Ascot Roadster Page

Ascot Roadster Construction Pages

Rogers Automotive Design International, Inc.

Completion Projection Summer 2002

Ascot Roadster Construction Project (Click Images to Enlarge)

PLEASE READ BEFORE PROCEEDING

The Design, Engineering and Construction of a Limited Production Automobile

This information is intended for the benefit of the designers, engineers and enthusiast working on the Ascot project and those intentionally directed to the site. This is not a commercial site and is intended for information exchange only. These pages follow the construction of a limited production roadster, from design concept to an operational prototype ready for testing and production. In many cases the latest revisions will not appear on these pages and the reader is cautioned to confirm the information provided here before using any of it in an important manner. Vendors, suppliers and contractors should contact the company directly for the latest revisions.

Project Overview

The Ascot Roadster is a two seat roadster with an 85" wheelbase and front and rear tracks of 58 and 57 inches respectively. The physical size of the roadster can best be considered about 3/4's the size of a typical, large, mid to late 40's style American car, with a wider front and rear track. It is a limited production, component vehicle, using fabricated or new parts only. The overall design is driven by the need to reproduce multiple identical vehicles, in production. This need changes the perspective from developing a one off Street Rod type vehicle, and in may respects is far more difficult. Cost of the construction and individual components are of major consideration in the design. As such, no donor vehicle is utilized. It is a design utilizing a purpose built rectangular tube frame, purpose designed suspension and a GRP (S fiberglass) body structure. Both the chassis and body will be produced completely in a prototype shop, in a manner consistent with a small, limited production facility.

Power is delivered by a new 225 HP rotary engine (Mazda 13B 6 Port, 225 lbs. with full accessories). This is a normally aspirated engine, using side draft carburetion. The torque characteristics of the rotary engine are ideal for a light weight, rear drive vehicle. The prototype uses a 5 speed transmission and solid rear axle with a limited slip differential. The engine bay has been designed with sufficient width and length to accommodate V6 and V8 alternatives as well, although this would increase the weight and effect handling considerably. The front suspension is un-equal tubular A arm and the rear is a 4 bar, offset Watts link locating system. Suspension, front and rear, are coil over shocks, adjustable in stiffness and ride height. The total vehicle weight is less than 1200 lbs, with a power to weight ratio of 5.33 lbs. per horsepower. This power ratio will provide extreme performance in the hands of an accomplished driver.

The same general techniques used in designing and producing a professional racing vehicle (the company has over 25 years experience in producing such vehicles) are being used in the development of the car. Suspension design and development has been accomplished on an in house vector generating computer program, capable of evaluating all relevant suspension movement interactions, simultaneously. The basic suspension design has been tailored for the expected use of the vehicle.

The original chassis and body concept hand drawings were converted to computer line drawings, then into rendered, solid 2D objects. These were then evaluated for proper location and function. The CAD output is then used as prints for fabrication or full size templates for cut-outs. In the case of the body construction, CAD templates are used to generate small scale body cross sections, which are used to develop a scale model for 3D evaluation.

Concept

The Ascot Roadster was designed as a affordable, high performance, fun vehicle, with highly visible, mid to late 1940's styling. It is a lightweight, precision design by race car designer Wayne Rogers. Styling of the roadster is being directed by Rick McDaniel. The American Bantam roadster undoubtedly has had an influence on the styling, both in size and concept. This is a mating of an extremely efficient, high performance mechanical design with the fun and romance of a mid 1940's classic body style.

The Ascot Roadster, represents in style, the car that was never made in American, due to the second world war. It represents the probable styling projections of a small American manufacturer, of perhaps 1945. The design was developed keeping the styling in the 1940's period and offers few visible hints of a modern productions design. It was not intended to be a "retro" styling effort, looking backward, but represents what might have been for that period alone. This same goal has been applied to the visible interior of the roadster. It is a continual struggle to achieve this design goal, and is all probability will not be 100% successful.

Construction Techniques Being Used

Chassis

The prototype chassis is built on a purpose constructed surface table. The chassis is constructed of rectangular steel tubing, laid out in a perimeter design. By using steel tubing, all chassis members are fully boxed. MIG welding, in a purpose designed jig, is used on the chassis, to reflect the production techniques to be employed. In this design all of the components of the vehicle sit on or are recessed into the chassis, but not below the bottom of the main frame rails. This allows a very low ride height without the concern of damaging vital engine or suspension parts.

Body

The body is constructed of GRP, or fiberglass. The paper design, transferred to the computer, is transformed to a scale foam model for evaluation. A wooden armature of precision shape, derived from the 3D model and computer output, is used to support the buck/plug for making the mold. A mold is taken from the completed buck and body parts are hand laid in GRP in the mold and pulled out for use. These pages will follow the progress of this construction.

**Basic Design Specifications**
Two Seat Open Roadster Four Wheel Disc Brakes 225 HP Rotary Engine 5 Speed Transmission Limited Slip Differential CAD Tubular Frame Construction 4 Bar Watts Link Rear End CAD Tubular A arm Front Suspension Rack and Pinion Steering	Adjustable Coil Over Shocks Adjustable Ride Height Front and Rear GRP Body Construction 1200 Pounds Total Weight 85" Wheelbase Front Track 58" Rear Track 57" Wheels 14 X 6 Front and Rear Tires 205-60-14 Wide Whitewall Front and Rear