If Pelmanism used to be a memory-training method, Ulmannism might be defined as trying to poke criticism at W.O. Bentley. Bentley-folk will recall how Alec Ulmann, the American historian, suggested that the Bentley BR1 and BR2 rotary aero-engines of the First World War were merely a crib of the French Clerget engine of the same type, and how Ulmann later suggested that Bentley had copied an Hispano Suiza pre-war engine when planning his 3-titre Bentley.
I do not think W.O. would have minded the latter suggestion very much, because in his biography he admits that he had looked at the 3-litre twin-cam Peugeot Coupe de L’Auto engine and the 1914 French GP-winning Mercedes engine before laying out his famous 3-litre Bentley power-unit. But he was very cross with Ulmann over the alleged Clerget-crib of his powerful and reliable rotary aero-engines and there is his letter to Motor Sport to prove it.
As the 1914 GP Mercedes was a single o.h.-camshaft, 16-valve design in which a vertical shaft and bevel gears drove the camshaft, I do not know why Ulmann wanted to suggest that it was an Hispano Suiza engine that W.O. had copied, unless as a compliment to Marc Birkigt, which the great Swiss designer certainly does not need! But that is what Alec did and now he has written to me saying that, following his, and I quote, “contention that W.O., or Walter as you call him, did a bit of plagiarising from the Hispano Suiza de Luxe model OHC 1913/14, let me relate what I learned recently from friends in France”. Ulmann then goes on to reiterate what we know about the T-head Alphonso XIII Hispano Suiza engine being followed by Birkigt’s experiments in Paris with a piston-type supercharger and rotary-valve head and how, when supercharging for racing was banned, he brought out an 85 x 130 mm. competition engine based on his single-o.h.c. 90 x 150 mm. and 100 x 180 mm. production engines, which had rockers operating valves, says Ulmann, inclined at 35-deg. in hemispherical heads. Ulmann diverts to remark that the special competition engine was used at Brooklands and elsewhere, implying that Bentley and others “no doubt examined it and recorded its performance”. He says “Massuger won a number of events with this model and that it did very well in the 1914 Eastern 100 long handicap meeting, driven by Brown at Brooklands”. Assuming that Alec means the Easter 1914 BARC meeting, I checked up, to discover that the 100 m.p.h. Long Handicap that day was won by Robertson Shersby-Harvie’s 8 1/2-litre rotary-valve Itala, from Stewart’s Crespelle and Joerns in a 1914 GP Opel, Brown in Rossiter’s Hispano Suiza being an also-ran. Ulmann says this Hispano Suiza became the 45 cm. wide “Sardine”, a car “capable of beating all comers at Brooklands . . . “
What he implies is that this was the same 3-litre engine as used for Birkigt’s unsuccessful blower experiments but with supercharger removed and a single o.h.-camshaft replacing the rotary-valve head, drive to this being by a vertical shaft, instead of the chain that had operated the rotary valves. This he says was imparted to him by Louis Massuger, Birkigt’s “testing executive engineer”. All this rather departs from Ulmann’s main contention, which is that in early-1914 Birkigt produced de Luxe versions of his single o.h.-camshaft 70 x 110 mm., 80 x 150 mm. and 90 x 180 mm. engines, giving these, not two, but four valves-per-cylinder. Ulmann sees this as confirming his earlier suspicion that W.O. Bentley used this Hispano Suiza design as the “source of information and intuition in designing the first 3-litre Bentley”. “So here”, he adds, “is one more reason to question W.O.’s claim to fame” ….
The matter may be worth investigation by dedicated Bentley enthusiasts and historians – they may think, as I do, that a two-valve hemispherical head would have been more de-luxe than a pent-roof, four-valve-per-cylinder head! For my part, I have not heard of these 16-valve Hispano Suiza power units, which maybe come into the category of the 1913 Espana Hispano Suiza which Vina and Sedgwick wanted us to believe had a twin-cam engine, when putting over their astonishing idea that Henry, far from having created the revolutionary 1912 GP Peugeot engine, had stolen the drawings of it from Birkigt! Yet investigation by researcher Griffith Borgeson, another American automobile historian, proved that the Espana actually had a single-o.h.-camshaft engine! However, Ulmann is emphatic that his French friends know of these four-valve-per-cylinder single-o.h.-camshaft Hispano Suizas, not to be confused, he says, with Birkigt’s other single-o.h.-camshaft engine, of 85 x 130 mm., in which the valves, two per cylinder, were vertical and prodded directly by the camshaft above them, as in the celebrated war-time Hispano V8 aero-engines and H6 car.
Ulmann also has a dig at Sunbeam, saying that, before it was abandoned, the supercharged 3-litre Birkigt engine developed 100 b.h.p. on the test-bed or 26 b.h.p. more than the winning Coupe de L’Auto Sunbeams, whose engines, at 2,500 lb., were 20 lb. heavier, he says. However, the answer here is that a race is won by the first car past the cheque red flag. . . The Hispanos didn’t even appear for the 1912 race, in which Ulmann says Pilleverdi and Derny had been nominated to drive them.
Leaving aside his prejudices against W.O. Bentley, Ulmann is a good fellow, who has just bought in Corsica a 1913 o.h.v. Hispano Suiza four-seater, fittingly for one who is so closely associated with the American Hispano Suiza Society, and he tells me that my ex-Forrest Lycett Alphonso Hispano is now owned by Uwe Hucke in Roquebrune.
But will someone please tell us more about the multi-valve Hispano which Bentley is alleged to have copied? Johnnie Green’s book on the make, being mainly pictorial, is superficial technically, Vina and Sedgwick do not refer specifically to it in “Lost Causes” or “Great Designers” (apart from the mysterious design Henry is said to have robbed Birkigt of; and as Sedgwick thinks this had hemispherical combustion chambers, it would be most unlikely to have more than two poppets-per-pot, even if we do not have proof that this twin-cam engine is apparently a figment of cruel wishful-thinking). Nor does Kent Karslake, in the first definitive Hispano Suiza history, which Motor Sport published 30 years ago. – W.B.