The next illustration shows a pull-rod set-up. The components and function are the same.
There are two differences: the suspension arm is connected from the top of the upright to the bottom of the chassis, and the internal components are lower in the chassis.
This set-up has two advantages over the push-rod. By placing the suspension components closer to the ground the centre of gravity is lower. Also the suspension arm is better able to condition airflow from the front wing towards the sidepod so in theory there is a small aerodynamic gain.
However, the chassis shape is constrained by FIA guidelines so the aero gain is not as great as it is when pull-rod suspension is used at the rear of the car.
There are two main disadvantages to front pull-rod suspension. One is that the the upper wishbone must transmit more load, some of which would otherwise have been carried by the push-rod. This means the chassis and wishbone needs to be strengthened – see the yellow circle. This adds weight and negates somewhat the CoG gain.
The second disadvantage is it takes longer tune a pull-rod. This is important given the limited testing time in F1 today. Teams need to rapidly tune spring and damper settings and if the components are hidden away this is trickier and potentially reduces valuable track time.
In summary the net benefit of switching to a pull-rod is a (very) small aero gain at the expense of tuning simplicity. The final illustration shows the pull-rod and push-rod side-by-side and the difference in geometry and CoG are apparent.
However, Gary Anderson raised an interesting point in Autosport that may further comprise the front pull-rod set-up.
By connecting the push-rod to the wheel upright the driver can use steering angle to affect the suspension. Under steering the natural movement of the push-rod reduce load transfer across the chassis and effectively allows a softer set-up.
The opposite happens with a front pull-rod so it is connected to the wishbone rather than the upright to counter this effect. Hence all else being equal you need to run a stiffer suspension set-up which compromises mechanical grip.
In short, Anderson’s assertion is that the pull-rod also has mechanical compromises that more than offset the (small) aero gains.
Without having access to a dynamo data and proper car models, quantifying the effect is difficult. But the logic appears sound. There is no doubt that when Red Bull introduced the rear pull-rod with success teams will have evaluated a front pull-rod set-up as well. That only one team has adopted it suggests if there is a gain it likely is not worth the hassle.
Please ... I want to hear more ... go on!An ex-Honda employee was at the McLaren factory, buying a P1 [some peoples have the worst of times :biggrin:], when he ran into some old faces from Honda big brass also visiting the McLaren factory. It seems there are some high level discussions going on over there............................
Please ... I want to hear more ... go on!
Interesting article, sounds like Honda thinking about being the engine supplier for McLaren in 2015:
"McLaren poised to switch to Honda engines for 2015 season"
http://www.bbc.co.uk/sport/0/formula1/21655985
Interesting article, sounds like Honda thinking about being the engine supplier for McLaren in 2015:
"McLaren poised to switch to Honda engines for 2015 season"
http://www.bbc.co.uk/sport/0/formula1/21655985