Friday, February 15, 2013

Complexity Caricatured: The BRM V-16

1949-1953 BRM 1.5 liter V-16 Formula 1 car, hoodless, at the Goodwood Revival.

This has turned out to be Multi-Cylinder Week on the blog.  It's interesting that, since the earliest days, the most successful Formula 1 engines have had 8, 10 (recently) or 12 cylinders.  Sometimes a 4 has been a winner, usually when other attributes of the car were more important than maximum power.  Never has a 16 been competitive--and BRM tried it twice.  I'm no engineer (although I sometimes play one on this blog...), but the evidence seems to be that 8 to 12 cylinders are the best compromise between piston area, friction losses, and mass.

I've mentioned "that distant sportbike in the night sound" that sends shivers up my spine.  On summer evenings, I often stop what I'm doing to savor it.  No car sounds more like a crotch rocket than the BRM V-16.  The first link is to an audio track illustrated with still photos.  It runs 7:30.  The first part is 3 laps of the car being demonstrated on a short course.  From 5:40 on, it's in-car, with gear whine.  The second link is to a much shorter video which shows the car well in HD.  The audio isn't as spine-tingling, but features some blower whistle.

"Caricatured" in this post title comes from the design and development history of the car.  This BRM seems to have been conceived as an uber pre-war Mercedes W-163 or Auto Union (but half the size).  Each cylinder had a bore and stroke of 1.93 inches and displaced 5.7 cubic inches.  As in small.  Instead of Roots blowers, BRM used centrifugal superchargers, like the ones developed for the Merlin aircraft engine by Rolls Royce (and donated to the BRM project by Rolls).  Centrifugal blowers work fine at high altitude: the faster they spin, the more they boost.  But in race car application they don't boost much at low revs, and come in with a wallop at high revs.  This made the BRM V-16 very hard to control from mid-corner through exit.  On straights, it could spin its tires at well over 125 m.p.h., even when the driver tried to modulate power.

BRM was poorly managed in the 1940's and 1950's.  The V-16 never completed an international race, and was DNS in most of them.  Once, the half-shafts of both cars snapped as they left the starting grid.
BRM was the first Formula 1 team to adopt disc brakes, but the car was so unsorted that they never got to test the brakes at race distances.  The chassis was a similar story.  The car suffered from massive understeer, but retained its trailing arm front suspension long after other designs had migrated to double A-arms with more balanced handling.  Trailing arms had been used by Mercedes and Auto Union before the war.  It seems that BRM, in the V-16 era, never quite got over its fixation with out-technologizing "those bloody German cars" that hadn't raced for over 10 years.   Juan Fangio and the best British drivers of the era tested it, offered suggestions for improvement, and took a pass on racing it.

Taken altogether, it seems the V-16 was doomed from the start.  The design was over-ambitious and ill-considered.  Many suppliers donated parts, usually on an "as time permits" basis, which played havoc with schedules.  BRM couldn't stop tinkering, and the team was managed more like a collection of amateur fiefdoms than a racing enterprise focused on winning.  But if engine sound equals winning, the  V-16 should have been a world-beater.

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