Tractor-trailer Combination Research Articles

The Tractor-Trailer Concept as a Timber Forwarder

SYNOPSIS The problems experienced with tractor-trailer combinations when operating with the conventional drawbar hitch, and how this knowledge led to the development of the weight transfer hitch, are outlined. The design parameters for the successful off-highway performance of a timber forwarder are discussed and it becomes apparent how the Prime Mover-Trailer combination fulfils these requirements. The factors affecting the selection of the right tyre for the job are discussed in detail, because these have a considerable influence upon the vehicle being a “go” or “no go” vehicle. The substantial cost savings that can be expected with the adoption of a Prime Mover-Trailer system for timber forwarding, as compared with the use of conventional vehicles, are substantiated. A single axle configuration should be adopted in preference to bogie axles for Timber Forwarders. The reasons leading to this conclusion are discussed. Timber Forwarders based on the Prime Mover-Trailer concept have been developed in Canad...

Reduced truck fuel consumption through aerodynamic design

Full-scale fuel consumption and drag tests were performed on a conventional cab-over-engine tractor-trailer combination and a version of the same vehicle with significant forebody modifications. The modified configuration had greatly increased radii on all front corners and edges of the tractor and a smooth fairing of the modified tractor top and sides extending to the trailer. Concurrent highway testing of the two configurations showed that the modified design used 20% to 24% less fuel than the baseline configuration at 88.5 km/hr (55 mph) with near-calm wind conditions. Coastdown test results showed that the modified configuration reduced the drag coefficient by 0.43 from the baseline value of 1.17 at 88.5 km/hr (55 mph) in calm wind conditions.

5. The braking performance of tractor-trailer combinations : M. J. Dwyer.J. Agric. Engng Res.15 (2) 1970

5. The braking performance of tractor-trailer combinations : M. J. Dwyer.J. Agric. Engng Res.15 (2) 1970

The braking performance of tractor-trailer combinations

Equations are derived for the maximum decelerations which can be obtained with balanced and unbalanced trailers with and without trailer brakes. The equations are used to produce graphs showing the maximum decelerations of trailers having typical dimensions, of different weights relative to the towing tractor on surfaces of different adhesion coefficients and with different types and degrees of braking on the trailers. Results measured during braking tests on tractors and trailers are given. Unbalanced trailers are shown to have a better braking performance than balanced trailers and it is therefore, recommended that trailers should be designed to carry the maximum permissible proportion of their weight on the tractor. Both over-run and power brakes on trailers are shown to provide very useful improvements in braking performance. Power brakes are preferred because of the difficulty of fitting over-run brakes on unbalanced trailers. The tractor's external hydraulics are considered to be the most convenient source of power. On-off brakes providing a fixed braking force equal to approximately 5–10% of the trailer maximum gross laden weight are considered to be a useful and simple means of improving existing trailers, but the development of trailer braking systems providing a braking force proportional to the tractor brake pedal force up to a maximum of approximately 20–30% of the trailer maximum gross laden weight is considered to be very desirable.

Handling characteristics of tractor-trailer combinations: F. Jindra.S.A.E. Paper, Combined Powerplant and Transportation Meeting, October 18–21, 1965, 14 pp.

Handling characteristics of tractor-trailer combinations: F. Jindra.S.A.E. Paper, Combined Powerplant and Transportation Meeting, October 18–21, 1965, 14 pp.

Off-tracking of tractor-trailer combinations: Jindra, F., Automobile Engineer, Volume 53, March, 1963

Off-tracking of tractor-trailer combinations: Jindra, F., Automobile Engineer, Volume 53, March, 1963