Backbone chassis
Backbone tube chassis is a type of automobile construction chassis that is similar to the body-on-frame design. Instead of a two-dimensional ladder-type structure, it consists of a strong tubular backbone (usually rectangular in cross section) that connects the front and rear suspension attachment areas. A body is then placed on this structure.
Design
The backbone chassis is a design feature of Czech Tatra heavy trucks[1] (cross-country, military etc.). Hans Ledwinka developed this style of chassis for the Tatra 11 in 1923.[2] He further enhanced the design with 6x4 model Tatra 26, which had excellent offroad abilities.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/02/%C5%A0koda_Rahmen_r.jpg/220px-%C5%A0koda_Rahmen_r.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/91/Lotus_Elan_car_chassis.jpg/220px-Lotus_Elan_car_chassis.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/3/30/De_Tomaso_P70_chassis_at_Turin_Motor_Show_in_November_1965.jpg/220px-De_Tomaso_P70_chassis_at_Turin_Motor_Show_in_November_1965.jpg)
This type of chassis is also often found on some sports cars. It does not provide protection against side collisions, and thus has to be combined with a body that would compensate for this shortcoming.
Examples of cars using a backbone chassis are De Tomaso Mangusta, DeLorean DMC-12, Lloyd 600, Lotus Elan, Lotus Esprit and Europa, Škoda 420 Popular, Tatra T-87, Tatra T111, Tatra T148, Tatra T815 etc., as well as TVR S1. Some cars also use a backbone as a part of the chassis to strengthen it; examples include the Volkswagen Beetle, where the transmission tunnel forms a backbone.
Hybrid backbone-ladder chassis
The Locost may appear to be using a backbone in addition to the outer space frame; however, examination shows that, in standard form, it is adding negligible stiffness and only serves as a convenient support structure for the sheet metal panels forming the transmission tunnel. The Triumph Herald and Triumph Vitesse used a twin flanged box section[3] backbone carrying the main torsional[citation needed] and bending loads, with light channel section side rails to stiffen the body, while the Triumph Spitfire and Triumph GT6 sports cars used only the twin-box section backbone, with separate side members in the body, and rear suspension fore and aft loads were also taken by the floor, not the backbone chassis directly.
Advantages
- A standard-conception truck's superstructure has to withstand the torsion twist, and subsequent wear reduces vehicle's lifespan.
- The half-axles have better contact with the ground when operated off-road. This has little importance on roads.
- The vulnerable parts of the drive shaft are covered by a thick tube. The whole system is extremely reliable. However, if a problem occurs, repairs are more complicated.
- The modular system enables configurations of 2-, 3-, 4-, 5-, 6-, or 8-axle vehicles with various wheel bases.[4][5]
Disadvantages
- Manufacturing the backbone chassis is more complicated and more costly. However, the more axles with all-wheel drive are needed, the cost benefit turns in favor of backbone chassis.
- The backbone chassis is heavier for a given torsional stiffness than a uni-body.
- The chassis gives no protection against side impacts.
See also
- Tatra concept
- Frame (vehicle)
- Body-on-frame
- Chassis
- Coachwork
- Monocoque
- Spaceframe
- Subframe
- Superleggera
- Swing axle
References
- ^ "Tatra AS". Archived from the original on 28 March 2010. Retrieved 22 August 2013.
- ^ "TATRA TAKES YOU FURTHER". Retrieved 1 July 2015.
- ^ http://www.paulstriumphherald.co.uk/wp-content/uploads/2016/08/10-1.jpg
- ^ "Build your own TATRA - Segment selection". Retrieved 1 July 2015.
- ^ "An all time longest and heaviest TATRA has been produced!". Tatra. 21 August 2015.
External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- Comparison of standard ladder chassis and backbone chassis with half axles on offroad testing track with emphasis on the twist of superstructure (video):
- Ladder chassis (Renault fire engine)
- Backbone chassis (Tatra T815 fire engine)