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Saturday, February 29, 2020

Deutsch Bonnet, DB and CD: The Path of Least Resistance

The firm Deutsch Bonnet was formed in 1938 by Charles Deutsch and René Bonnet to build race cars at the location occupied by the Deutsch family coachbuilding firm, which Bonnet had bought in 1932. The first cars were based on Citroen power plants, and had some racing success before war ended all that. After the war the partners built a few more Citroen-based cars, but limited availability of engines prompted them to switch to Panhard power trains.  Because this was the postwar Panhard Dyna X, front-wheel drive went along with it.  By 1950 the firm (now known simply as DB) exhibited  a handsome cabriolet at the Paris Show. The smooth forms by Carrosserie Antem cover a horizontally-opposed twin cylinder air-cooled engine with four-speed transaxle in a special backbone chassis.
By 1952 DB had won its class at the Mille Miglia, and celebrated by releasing a Mille Miles model, a steel-bodied coupe designed and built by Frua in Italy.  The race car above shares its grillle design with Panhard's production cars, while the version below features a simple air intake and functional porthole fender vents.

By the time DB introduced the HBR-5 coupe below in 1954, all their production car bodies were fiberglass and engine displacement was up to 850cc. This was their most popular model, with several hundred produced; total production of DB cars has been estimated at over 900.  Road & Track tested a similar car in 1957, heaping praise on the roomy, well-furnished interior, while pondering features like the transparent orange plastic sunroof (non-retractable), the inscrutable controls for heater, windshield washer and hood release, and the even stranger cable-operated lateral floor shift, in which first is back and to the left, 2nd is straight across to the right, 3rd back to neutral, forward and then left, and 4th straight across again to the right. This was changed to a more conventional pattern after 1957, and at some point the tidy little coupe traded its retractable headlights for the covered units shown below.

Road & Track recorded a zero to 60 time of 21.3 seconds while noting that a French journal managed it 3 seconds quicker with a slightly lighter DB.  While the car was not a rocket ship, R & T noted the DB might be fast enough to take home a Class H Production trophy, and do it in style. The price in San Francisco that year was $3,850.  For perspective, the Porsche 1600 coupe the magazine tested that same year had a list price of $3,790. 
The streamlined HBR-5 Le Mans barquette shown above was probably quicker and certainly faster; it resides today in the United States. The same pursuit of the Index of Performance at Le Mans that produced this streamlined open car in the late Fifties led aerodynamicist Charles Deutsch to seek the lowest possible drag coefficient in his designs: C.D. chasing a lower Cd, as it were...  
Seeking the path of least resistance was important because the firm limited itself to Panhard's twin-cylinder; in Class H this was 850cc. The slippery barquette design shown above appeared in 1959, and won the Index of Performance at Le Mans in 1960 and '61. The race organizers calculated the Index by comparing a car's average speed during the race with its engine capacity. The Index allowed French sports cars powered by tiny production-based engines—that is, all of them after the disappearance of Talbot-Lago* and Gordini*—to bask in their own winner's circle until the late Sixties when Alpine Renault and Matra would seek an overall win with V8s and V12s.  The blue spider in the foreground, like the black Lotus Eleven in the background, represented a kind of grand finale for the aerodynamics of front-engined road racers. To reduce their air resistance and frontal area further, and to improve their physics, the next step was the mid-engined car.  René Bonnet wanted to make that move; Charles Deutsch preferred to chase the ideal Cd by making low-drag closed coupes with front-mounted Panhard power trains. Note the metallic blue coupe above our DB spider, also numbered 46, and hold that thought for a moment... Deutsch and Bonnet dissolved their partnership in 1961, after Bonnet had signed a contract with Renault. Deutsch continued to coax maximum performance from Panhards, releasing the CD Dyna coupe, a version of which finished 16th at Le Mans in 1962 with a 702cc engine.  Following it in 17th place was a mid-engined René Bonnet Djet coupe like the metallic blue one above, with a Djet 2 spider in 18th. The mid-engined revolution was not complete, and hadn't yet convinced Charles Deutsch...
After running a DKW-engined car without success in 1963 (when a Bonnet Aerodjet finished 11th) Deutsch had one more try, building two supercharged, 850cc CD Panhard LM64 coupes. Chassis design was similar to the production CD coupes but with coil spring front suspension and 5-speed ZF transaxles. The long-tailed, flush-windowed body with its stabilizing fins offered lower air resistance than either the production coupe or the previous open racers, but both cars retired with mechanical maladies…
Remember that other #46 parked above DB's #46 racer?  René Bonnet designed his mid-engined Djet around Renault engines in 1962, and finally achieved his idea of a dual-purpose car for racing and touring by mating the 1,100cc motor with a transmission from the Renault Estafette, a front-wheel drive van.  The #46 coupe raced at the 1962 Le Mans and shown below, used a special engine with dual overhead cams on the Renault block. What Jean Redelé, who had just introduced the future rally champ Alpine Renault A110 the previous year, thought of Bonnet's competing agreement with Renault has not been recorded, at least not in English...        
The mid-engined Djet (Bonnet added the "D" so the French would pronounce "jet" the English way) never attained the rally and racing success of the rear-engined Alpine A110, but caught the eye of aerospace concern Matra, which partnered with René Bonnet's firm after he had sold almost 200 Djets between 1962 and '64. These Djets are sometimes considered the first mid-engined production cars, though 66 cars a year is pretty limited production.  Matra Djets sold better, with nearly 1,500 produced between 1965 and '68.  The cars never had the level of development Alpine gave the competing A110, which remained in production until 1977.  Instead, Matra sought a wider public and sold over six times as many of their M530, a 2 + 2 with mid-mounted Ford Taunus V4 power and avant-garde fiberglass bodywork. That car, however, was not a project involving René Bonnet, who left the car business and died in a road accident in 1983.
Charles Deutsch, finally convinced to take the mid-engined route, designed a sports prototype based upon the then-new single overhead cam Peugeot 204 engine for the 1966 Le Mans. The compact 1.1 liter inline four parked behind the smoothly rounded cabin necessitated a search for low drag, as had the tiny Panhards. The body design, by aerodynamicists Lucien Romano and Robert Choulet, must have pleased Deutsch because it brought the Cd down to an astonishing 0.13.  Three CD Peugeot SP66 coupes were built with adaptable short tails and elongated, finned tails (shown above and below), and these could be easily changed to adapt to track conditions. The cars dropped out from the '66 and '67 runnings of Le Mans with clutch and other maladies, but one SP66 took 2nd in class at the '66 Magny-Cours race, and 3rd in class at the '67 Reims 12 Hours.  Charles Deutsch left his role as car designer in 1967 to take a job as director of the Le Mans 24 Hours, and also served for a time as Minister of Transport.  Aerodynamicist Robert Choulet moved into the era of big-time French road racers with his design for the radically streamlined, similarly finned Matra MS640 coupe in 1969, but the saga of the big V12 Matras is best saved for telling another day...
*Footnote:  The history of the Gordini sports racers and GP cars is surveyed in our post from March 27, 2016, "The Etceterini Files Part 6----Gordini: French Connection, Chicago Subplot." 

*Postscript:  Talbot-Lago cars were finally given a retrospective, with a trove of previously unpublished photos, in "Talbot-Lago:  Darracq by Another Name", in these posts for May 22, 2020.  And we finally had a look at the Matra saga in "Forgotten Classic: Matra---Maybe It Was Rocket Science", posted on December 31, 2021.

Photo Credits:
Top: classiccarcatalogue.com
2nd: panhard-racing-team.fr
3rd & 4th:  bonhams.com
5th thru 8th:  wikimedia.org 
9th & 10th:  en.wheelsage.org 
11th:  petites-observations-automobiles.com 
12th:  wikimedia.org
Bottom:  FIVA (Fédération Internationale des Véhicules Anciens)

2 comments:

  1. Thank you for posting this wonderful blog about the firm Deutsch Bonnet. I'd like to congratulate you on your work. Have a great rest of your day and keep up the posts.
    Lawyer

    ReplyDelete
  2. Thanks for having a look; we'll try to get back to Matra later this fall.

    ReplyDelete