GB2501892A

GB2501892A - Drag reducing clothing

Info

Publication number: GB2501892A
Application number: GB1208082.6A
Authority: GB
Inventors: Robert William Lewis
Original assignee: UK Sport Ltd
Current assignee: UK Sport Ltd
Priority date: 2012-05-09
Filing date: 2012-05-09
Publication date: 2013-11-13
Also published as: GB201208082D0

Abstract

An item of clothing, suitable for use by a sports person, comprises one or a plurality of air flow disruption devices disposed on the rear outside of one or more limbs. The devices, which are positioned generally transversely to the axis of a limb of a wearer, reduce air drag on the body, in such sports as cycling, skiing and motorcycling. They may be positioned on the arm or the leg of the sports suit and preferably comprise chevrons whose apexes point towards the top of the limb concerned. Other shaped devices may include kicks in the form of dams, which may be arranged singly or in groups. The air flow devices may also comprise pockets whose openings are downwards away from the top of the limb concerned.

Description

DRAG REDUCING CLOTHING AND METHOD

This invention relates to clothing to reduce air drag on about the body of person, particularly one involved in cycling, skiing or motor cycling.

It is an aspiration in sports such as cycling, skiing and motor cycling as far as possible to reduce air drag on the body. This invention particularly relates to devices to reduce such drag on arms and leg According to the present invention an item of clothing for a sports person is characterised in having one or a plurality of air flow disruption devices disposed on the outside rear limb of the item of the clothing item, and generally transversely to the axis of a limb of a wearer.

In this context "rear" means the part of the limb opposed to the anticipated direction of travel.

The limb is eithoran arm or a leg. Normally, clothing on both arms and legs will incorporate the invention.

Increasing the number of devices per limb reduces drag further although the practical maximum is about ten In practice best results were obtain using nine such kicks spaced at about 50mm apart.

The air flow disruption devices in one embodiment comprises kicks in the form of a chevron or dams, normally in ilie chevron arrangement the apex points to the top of the top of the limb concerned.

The air flow disruption device in another embodiment can comprise pockets whose openings are downwards away from the top of the limb concerned.

It has been found that in cycling, air to the rear of an arm or leg flows upward along the arm or leg and is a significant cause of overall drag on the cyclist. By including an air flow disruption device on the rear of the arm or leg, this flow is broken up, reducing the overall drag.

In another aspect of the invention, a method of reducing drag around the body of a person includes the step of providing an air flow disruption device to the of a limb of The person, said air flow disruption device being disposed transversely to the axis of the limb concerned.

Examples of the invention are illustrated in the accompanying drawings, in which: Figur 1 A, 1 B, 10 and 1 D show the use of kicks on the rear of the arm a cyclist's suit; Figure 2 shows the use of pockets on the rear upper arm of the suit a cyclist.

In figure 1A to 1 D, a cyclist has a cycling suit 10 whose arms 12 have disposed on the rear thereof, a plurality of kicks. In figure 1 A the kicks are in the form of dams 14, in figure 1 B they are in the form of chevrons 16 whose apexes point down the arm to the hands, in figure 10 they are in the form of chevrons 18 whose apexes pointing up the arm. The ends of the kicks can be chamfered to avoid a sharp angle at the ends as shown in figure 1 D, which shows a dam 14 of the kind used in figure 1 A with a chamfered portion 15 at either end -the same principle can be applied to chevron shaped kicks. A sharp angle at the end of the kicks would itself be a cause of vortices in and air flow and a source of drag.

Table 1 below sets out the results obtained for a sprint cyclist using 3mm kicks.

Example Form No of Drag reduction Drag reduction Kicks on body on arms compared with (average of left no kicks and right) ______________ __________________ __________ (Newtons) (Newtons) 1 DamsasfiglA 3 -0.29 -0.18 2 Dams as fig 1A 5 -1.09 --0.73 3 Dams as fig 1A 10 -1.35 -1.04 4 Ohevrons as fig 1 B 3 0.89 0 Chevrons as fig 1 C 3 -1.04 -026 6 Ghevrons as fig 10 5 -1.22 -1.02 7 Chevrons as fig 10 10 -2.10 -1.74

Table 1

Chevrons whose apexes point towards the wrist have little impact on arm drag and it anything increase over all drag. In contrast when reversed, so that apexes point up the arms towards the shoulders, chevrons achieve considerable reductions. It was also found that if the upper chevron was too close to the shoulder, drag in its wake tended to increase; this was not apparent with the dams of figure 1A. Interestingly the drag raluctionwas found to have occurred both on the back of the arm and side of the arm Some optimisation is possible by trimming the width of the kicks by 10mm back from extending across the whole width of the arm. This reduces the variation of performance arising from varying arm positions, ensuring that the edges of the kicks were never caught in the wind. Overall best results were obtained with nine reversed chevron kicks having an angle of 90° between the arms of the chevron The kicks, reverse chevrons and dams, perform best with a height of 3 mm and spaced about 50mm apart, increasing the height tended to decrease slightly the drag saving, although heights up to 7mm all produced significant reductions, Increasing the number of chevrons beyond nine also reduced the drag saving. For the configuration of nine chovrons, 3mm high and spaced apart by about 5ommthe total drag reduction obtained was 2.08 Newtons with a total reduction on the arms of 2.10 Newtona It has also been found that as air speed increases the drag saving on the arms with this invention also increase with ten chevrons each 3mm high from 1.33 Newtons total at 1 4m/s to a total of 2.94Newtons at 20m/s. However, the greatest overall drag reduction occurred at 1 7m/s, with the total body drag saving declining somewhat with air speeds above that (but still significant).

It was found that similar kicks on the lower leg towards the ankle produced drag savings too. The results were more variable than those obtained from the arm, because or greater variations in the leg positions of the trial riders, however the principles are the same. Placing kicks on the thigh also reduced drag on the thighs but at a cost of an increase in overall drag on the cyclist.

In figure 1 the kicks can be made of any suitable material, but conveniently they are moulded plastic material stuck onto a cyclist's suit. Alternatively they can be made by heat moulding the material of the suit itself.

Generally the kicks should be 50mm or more across, although kicks extending across the whole width of the rear of the arm (less 10mm at their edges) are most effective.

Pockets sewn onto the arm of racing suits also produced drag savings, although not as great as those for kicks. In both tie case pockets the width of the pocket should be at least 30mm. The effect of the depth of the pockets was similar to that of the depth of the kicks.

The pockets are illustrated in figures 2A and 2B. A portion of a cyclist's suit 30 between the elbow 34 and shoulder 36 is shown. A number ot pockets 38 are sewn onto the suit with the pocket opening 40 towards the elbow 34 (fig 2B). The airflow 32 passes into the pocket opening, which disrupts its progress up the arm, thus producing a similar effect to the kicks discussed with reference to figures 1A to 1 D. It has been found that pockets less than 30mm wide are not effective. The height of the pocket opening seems less critical.

Claims

Claims 1. An item of clothing for a sports person is characterised in having one or a plurality of air flow disruption devices disposed the rear outside of one or more limbs of the item of the clothing item, and generally transversely to the axis of a limb of a wearer.
2. An item of clothing comprising a cyclist's racing suit characterised in having one or a plurality of air flow disruption devices disposed the rear outside of one limbs of the item of the clothing item, and generally transversely to the axis of a limb ot a wearer.
3. An item of clothing according to claim 1 or 2 oharacterised in that the limbs are the arms.
4. An item of clothing according to claim 1 or 2 characterised in that the limbs are the arms.
5. An item of clothing according to claim 3 characterised in that the limbs also include the legs.
6. An item of clothing according to claim 4 or 5 characterised in that the air flow disruption devises are disposed on the lower leg just above the ankle.
7. An item of clothing according to any preceding claim characterised in that the air flow disruption devices comprise kicks.
8. An item of clothing according to claim 7 characterised in that the kicks comprise chevrons whose apexes point to the top of the limb concerned.
9. An item of clothing according to claim B characterised in that the arms of the chevron from a right angle at the apex of the chevron.lOAn item of clothing according to claim 7 characterised in that the kicks comprise dams.11.An item of clothing according to claim 8, 9 or 10 characterised in that the kicks are less than 7mm high.12.An item of clothing according to claim 11 characterised in that the kicks are about 3mm high l3.An item of clothing characterised in that between three and ten kicks are disposed on any one limb.14.An item of clothing characterised in that nine kicks are disposed on an arms.15.An item of clothing according to claim 13 or 14 characterised in that the kicks are spaced about 50mm apart.ThAn item of clothing according to anyone of claims 7 to 15 characterised in that kicks extend across the width of a limb on which they are mounted.17.An item of clothing according to anyone of claims 7 to 15 characterised in that kicks extend genorally across the roar of a limb but are cut back by 10mm at each of their ends short of the full width for the limb concerned.18.An item of clothing according to any one of claims 7 to 17 characterised in that the kicks are chamfered at their ends.19.An item of clothing according to any one of claims ito 6 characterised in that the air flow devices comprise pockets whose openings are downwards away from the top of the limb concerned.20.An item of clothing according to claim 19 characterised in that the openings in pockets are 30mm or greater.21.A method of reducing drag around the body of a person inducing the step ot providing an air flow disruption device to a limb of the person, said air flow disruption device being disposed transversely to the axis of the limb concerned.22. A method of reducing drag around the body of a person according to claim 21 said method utilising kicks extending transversely across the rear of a limb o the person.23.A method according to claim 21 said method utilising pockets having openings extending transversely across a limb of a person, and the openings of said pockets facing down the limb.24.An item of clothing substantially as hereinbefore described with reference to the accompanying drawings.25.A method of reducing drag around the body of a person substantially as hereinbefore described with reference to the accompanying drawings.