It took half season for HRT to launch the first update of its 2011 spec wing ( the version raced back inAustraliawas actually a 2010 wing ) . The revised wing with the oversized and reshaped cascade winglets wasn’t able to change the natural grid order of course and HRT remained at the far back. However it is admirable to see small teams put hard effort to gain speed with minimum budget .
In slow and high downforce street track of Monaco , HRT F111 inherited an extra single element winglet over the rear light to increase the stability of the rear end . Nevertheless during the whole weekend the team faced balance problems on both cars , problems difficult to be delt properly due to reduced amount of free running . Luckily for the team both drivers managed to finish race , something really important for HRT .
In China Liuzzi raced with a fin-less engine cover in contrast to Karthikeyan ( lower illustration in yellow ) . The shark fin improves car streamline but has a negative impact as it makes the car more sensitive to side winds . Liuzzi choice to reject the shark fin can be justified by the fact that his car version in Sinopec had less rear axle winglets ( https://formula1techandart.wordpress.com/2011/08/20/hrt-f111-rear-axle-winglets-revisions/ ) which provided less aerodynamic grip to the rear axle. So keeping the shark fin could potentially cause handling issues of the rear end and even excessive ware to the rear tyres . Liuzzi returned to the standard version of F111 after China , with three winglets per rear brake and an engine cover with the shark fin .
More rear wing revisions took place at Turkey with a series of 5 curved gills were put on the endplates to lower significantly drag production generated by the wing , with a small downforce loss as a side effect but giving more freedom for steeper attack angles at the same time . This was the first serious upgrade for the rear wing as the previous were only refinements of the original version .
It is very interesting to investigate HRT rear brake winglets development over season, which reflects in some occasions the different driving style between the two drivers of the team . Initially the F111 run with asymmetric winglets (red arrows).This asymmetric configuration offers sufficient grip to the inner rear car side, which is shadowed in a right hand turn , something important to reduce rear pitch sensitivity having in mind that both Melbourne and Sepang circuits feature more right hand turns than left ( 10R/6L , 10R/5L respectively) .
Later the season at China two versions of symmetric configurations were applied on the rear axle. More experienced Liuzzi raced with single winglets while Karthikeyan raced with double winglets which offered a more stable rear end .
Finally since Turkey both drivers race with symmetric rear axle winglets but increased in number up to three elements at each side . The brake winglets are considered to be part of the braking system and as long as they are within FIA dimension rules are considered to be legal .
F111 rear wing is consisted of a rather large movable flap compared to other teams with a black colored tab fence (1) across the trailing edge , two flap fasteners (2) , gill-less endplates and finally the wing is supported on a single vertical element (3) which also houses the flap moving mechanism .Having a closer look on the endplates we can observe the uncovered flap angle adjuster (4) and the flap connecting spots (5) to the endplate body .
In China HRT decided to put elegant white colored coverings on rear wing’s flap adjusters to cut turbulence created by the anomalies on endplate surface . Meanwhile the two lower dot style flap connectors to the endplate were already covered since Malaysia( red arrows ) .
The F111 follows also the trend of exhaust blown diffuser having the exhaust pipelines ending close to the rear crash structure . There is a pair of vertical fences (in yellow) twisted outwards in either side section of the diffuser pattern and also a high tab fence across the diffuser roof extending even to its vertical sides to improve air sanction. Of course the tab partially blocks the hot exhaust emissions preventing a stronger blending of them with the air coming from under the floor, a situation by passed by some teams, like Red Bull, Lotus Renault and Toro Rosso for example, using a slotted tab fence .