The success of the pioneer monocoque Lotus 25, and its derivative the 33, has long been the stuff of legend, and rightly so. But I sometimes wonder if the BRM P261, which of course followed the leader (as did Ferrari and others), has not been given the credit it deserves.
For one thing, they avoided the “bathtub” design, wrapping the outer shell all the way around ahead of the dash panel, and thus enclosing the driver’s legs, which is inherently both stiffer and stronger, hence safer. Restricted access to the pedal area was a small price to pay for such advantages, I should think.
Somewhat less obvious is the way in which the other end of the monocoque was also strengthened and stiffened. By arranging the V8 with intake ports between the camshafts, and exhaust ports inside the V, instead of outside as is usual, enough space was left for the “wheelbarrow arms” cradling the engine to be made deep and hence stiff. Which should have increased the stiffness and strength of the chassis as a whole, both in bending and in torsion. It would be interesting to see some comparative figures for torsional stiffness of the P261 vs the T25/33. As I understand, measurement of this parameter was not unusual, and, assuming a similar test procedure, such a comparison might be meaningful.
Tucking the exhaust pipework behind the driver’s head, instead of low down on either side, may also have given a small improvement in aerodynamic drag, considering the fairly narrow wheels and tyres of that era. Figures for this might be hard to come by, however, as I am not sure how much wind tunnel testing was done, and if so, whether the tests featured a moving ground plane and rotating wheels.
Anyone have any information on these? Thanks in advance.