Blade-Style Roll Hoops

[Neco FEROX]

2011 rule changes - blade-style roll hoops
http://www.formula1.com/news/technical/2011/0/816.html

Can someone explain to me what the FIA's mandatory changes (link above) are because they're not banned because the T128 & VJM04 use the design that was introduced on the MGP W01 by Mercedes GP at the 2010 Spanish Grand Prix (link below).

2010 Spanish GP Mercedes GP MGP W01 - revised airbox and roll structure
http://www.formula1.com/news/technical/ ... 8/746.html

[scuderiafan]

They are allowed, but the actual "blade" has to be of a certain thickness to pass.

[MIKEY_!]

FIA Technical Regulation
15.2.4 - The principal roll structure must have a minimum enclosed structural cross section of 10000mm², in vertical projection, across a horizontal plane 50mm below its highest point. The area thus established must not exceed 200mm in length or width and may not be less than 10000mm2 below this point.

[N12ck]

Why dont f1 teams run these anymore, what are the advantages and disadvantages, I expected in f1 2012 for most people to run blade roll hoops, but they didnt, hmmm?

Nick

[MIKEY_!]

so did i. the main advantage for MGP in 2010 was the freedom to change the shape and position of the airbox. there is also the advantage of better airflow to the RW and maybe less drag due to a smaller cross-section. it's usually heavier due to the use of more metals in the blade than a roll-hoop (or so i've heard) and because the hoop shape is inherently stronger than a blade shape. the positioning of the airbox intake can sometimes block air to the RW as in the cases of the force india and caterham last year as the intake were actually right in front of the RW leading edge while a conventional airbox only has a teardrop cross-section in front of that leading edge. A very low intake can clean up turbulent air behind the cockpit but that also reduces it's cooling/engine feeding efficiency.