Saturday, August 18, 2012

The 1982 Grand Prix season: A bibliography

Autocourse 1982 (Maurice Hamilton).

Decent race reports from Maurice Hamilton, old-style lapcharts, and an excellent technical survey from Doug Nye. Photography, however, is mainly black-and-white, and fairly average.

1982: The inside story of a sensational Grand Prix season (Christopher Hilton, Haynes 2007).

A desert-island book, this one. A superb account of the season, full of insight from the major players. Good selection of photographic images as well.

Autosport 1982 (Nigel Roebuck, available on

The best race reports from 1982. Roebuck at his peak: pithy, judgemental, and on occasion, devastatingly sarcastic. Although there's a somewhat curious over-use of ellipsis...Only disappointment of the downloadable versions is the photography, which consists of some very bland images from the LAT archive.

When F1 Ran Wild (Autosport, August 16th 2012).

Interesting Mark Hughes profile of Keke Rosberg, and Frank Dernie annotated cutaway of FW08, but the latter is less informative than one would have wished (compare and contrast with Frank's guide to the FW07 in Motorsport, November 2004, pp75-77).
Formula One's Wildest Year, (Motorsport Magazine, February 2002).

Short insights into a particular facet of each race from various authors, but accompanied by Keke Rosberg's race-by-race recollection of the season. For this reason alone, indispensable.

Monday, August 13, 2012

Autosport and 1982

A 1982 extravaganza is promised this week, both in Autosport magazine, and on The latter, in particular, are undertaking to publish all of Nigel Roebuck's 1982 race reports, and this will be a real treat.

Back in the 1980s, there seemed to be an understanding that the entire race weekend provided a captivating story, replete with numerous strands, which could be followed from practice on Friday all the way through to the end of the race. Each report duly began with an 'Entry and Qualifying' section, in which the context for the weekend was established, the main plot-lines drawn, and the technical innovations were explained, all tied together via anecdotes and conversations with the drivers. 

To some degree, things have changed irreversibly in the years since: the drivers are no longer directly accessible to journalists, and practice no longer features the mechanical dramas it once did. The engineers, however, continue to be reasonably open to enquiry, and there is still very much a weekend-long story to be charted. Thus, whilst the quality of the technical information these days is incomparably superior, and whilst the writers themselves are not to blame, something important has been lost from motorsport journalism.

Anyway, as some recompense, enjoy the video above of Keke demonstrating the art of overtaking at Zandvoort. Pay particular attention to how close he's able to sit behind Tambay going through Bos Uit, the fast corner onto the main straight. 

And watch out for Warwick's rear wing flying off in the corner of the picture as Rosberg overtakes Lauda!

Saturday, August 11, 2012

Experimental British Nuclear Reactors

The book featured here was published by the Atomic Energy Research Establishment in 1960. It contains cutaway drawings of several British reactors. All the experimental reactors featured have now been shut-down. Replacements have not been commissioned.

Suffice to say, there are no plans for a second edition of the book.

Publications you can look forward to, however, include the following:

Indian Nuclear Reactors
Iranian Nuclear Reactors
The Occidental power crisis of 2025
The technological decline of the West
The Triumph of the Thickos

Saturday, August 04, 2012

The Grid Girls' Guide to Wind-tunnel/CFD Correlation

A number of grid girls have contacted me recently, complaining that the F1 Show on SkySports fails to provide the level of informative technical discussion they seek in a programme nominally targeted at the motorsport enthusiast.
In particular, they've asked to understand a little more about the correlation issues which crop up between Computational Fluid Dynamics (CFD), wind-tunnel testing, and full-scale track testing. 

Perhaps the best way to begin such an explanation is to introduce the concept of a commutative diagram, familiar to all mathematically inclined grid girls.

The idea here is that two operations can be applied to object A. One operation is depicted as a horizontal path, the other as a vertical path. If the same result is obtained irrespective of the order in which the operations are applied, then the operations are commutative. In terms of the labelling in this particular version of the diagram, it is written that:

Now, in the motorsport arena, aerodynamic data can be acquired by four distinct means: (A) Scale-model CFD simulation; (B) Scale-model testing in the wind-tunnel; (C) Full-scale CFD simulation; and (D) Full-scale track testing. 

Whilst the data acquired from full-scale track testing can be treated as veridical, it has increasingly been considered to be an expensive means of generating such information, and has therefore become a severely limited form of data acquisition. This has placed greater emphasis on CFD and wind-tunnel testing. However, both of the latter techniques have systematic errors associated with them, and to go from one data set to another requires the application of correction factors and more general mathematical transformations. For example, scale-model testing in the wind-tunnel can only be mapped to full-scale data if correction factors are applied for the blockage imposed by the walls of the wind-tunnel. Moreover, it is impossible to replicate both the Reynolds number and the Mach number of the full-scale flow with a scale model, hence Reynolds number corrections must be introduced.

Given any pair of data-sets, if one of them can be treated as veridical, then a regression analysis can establish the corrections which must be applied to compensate for the bias of the non-veridical data-set. One might, for example, have CFD and wind-tunnel coefficient-of-lift (CL) values for each combination of ride-height and angle-of-attack. By allowing a single parameter to vary (e.g. angle of attack), a particular set of paired CL-values can be isolated and represented as a scatter-plot, the x-coordinate of each data-point being the wind-tunnel CL-value, the y-coordinate being the CFD CL-value. A regression analysis then establishes a functional relationship between the CFD coefficients and the wind-tunnel coefficients.

A vital test to ensure that one has a self-consistent scheme of correctional transformations is to test for the commutativity of these relationships. Thus, for example, if one begins with a set of half-scale wind-tunnel data, one should be able to: (i) map the half-scale wind-tunnel data to scale-model CFD data, then map the scale-model CFD data to full-scale CFD data, and then map the full-scale CFD data to full-scale track testing data;  (ii) map the half-scale wind-tunnel data directly to full-scale track testing data; and (iii) the results of these two transformations should be in agreement, within some reasonable approximation. If there is any doubt, the results should be statistically tested with something like Analysis of Variance (ANOVA) to determine if the variation is simply the result of random sampling error.

Similarly, one should be able to start with half-scale CFD data, and map the results to full-scale track testing data by the two possible routes, without getting different results. In terms of the commutative diagram we started off with, there actually needs to be a bi-directional arrow between objects A and B.

As ever, the generalities are simple, the implementation difficult and messy.

Friday, August 03, 2012

A query about the BT42/44

Gordon Murray's place in the F1 design pantheon is assured, but a question arises over the aerodynamics of the iconic BT42 and BT44.

Speaking to David Tremayne some years ago, Murray explained his rationale as follows:

"I knew a lot about aerodynamics from practical experience. With any moving form you have a stagnation point where air meets it and decides how much is going to flow over, below or around it...I decided, instead of presenting some sort of parabolic-shaped bluff body to the air, I wouldn't give the air a chance." He sketches a triangular shape. "That way the stagnation point was there," he says, pointing to the leading edge of the triangle's base, which is very low to the ground. "So all the air had to go over the top and you had the minimum coming under the car," (F1 Magazine, May 2001, p140-141).

Murray spoke about this issue more recently on the BBC4 documentary, 'How to go faster and influence people':

"The BT42 was like an upturned very little air went underneath the car and most of it went over the top, because all the air that goes under the car produces lift, which counteracts the downforce you're getting from the wings."

This leaves me slightly confused, for a couple of reasons: (i) my understanding is that air going over the top of the car will be accelerated by the curvature, and will therefore produce lift; and (ii) the best way to generate downforce is to turn the region between the ground plane and the floor of the car into a mobile nozzle.

The greater the mass-flow beneath the car, the better; hence the presence of a diffuser, whose 'pumping effect' is maximised by increasing the ratio between the outlet area and the area of minimum cross-section at the leading edge of the floor. The raised nose on a contemporary F1 car also presumably contributes to increasing mass-flow under the car, although it's also designed to minimise the turbulent intensity of the air feeding the underbody.

But Gordon Murray is clearly no mug, so why does he think that it's important to minimise the air going under the car? My best guess is that Murray's idea was specific to cars from the 1970s, which lacked diffusers and raised noses. If there's no diffuser pumping air under the car, then perhaps excess underbody flow can be detrimental.