In your description of the Gregoire car the gear ratios are quoted in an apparently noveI fashion, which I find incomprehensible. May we, please, have some further information?
In connection with the same article, I fail to see how a 7-1b. supercharge could raise the power output from 15 to 25 b.h.p., unless the engine speed is also greatly increased. Even if the supercharger were completely efficient, I believe that 22 b.h.p. is the most that could be hoped for.
I quite agree with your editorial comment about the use of three cylinders.
I very much hope that Motor Sport will shortly be able to publish a road test of this important newcomer; also the Healey, of whose roadholding and cornering powers I hear golden opinions from one who should know.
May I express my great enjoyment of once more reading “Baladeur’s” contributions to Motor Sport after an absence of, I believe, exactly nine years.
I am, Yours, etc.,
[Mr. Parker’s comments follow. — Ed.!
The gear ratios quoted – 0.325, 0.65, 1, and 1.28 — are the degree of turn required at the input end of the gearbox to achieve an output of one revolution, in the different gears.
It would be more orthodox to quote the gearbox ratios: 1st, 3.08 to I; 2nd, 1.54 to 1 ; 3rd, 1 to 1; over-drive. 0.78 to 1; or the overall ratios (through the 5.71 back axle) as: 1st, 17.59 to 1; 2nd, 8.79 to 1 ; 3rd, 5.71 to 1; overdrive, 4.46 to 1. I am sorry to have caused confusion by using the continental method.
The Gregoire engine is deliberately limited to a maximum of 15 b.h.p. at 4.000 revs. (less than 80 b.m.e.p.) under which conditions the inlet manifold pressure would be well below atmospheric. With a pressure of 7 lb. above atmospheric in the manifold — probably giving a 100 per cent. pressure rise — I feel that 25 b.h.p. (still only about 117 b.m.e.p., allowing for supercharger loss) would be a conservative estimate.
Mr. Clutton’s 1908 12-litre Itala gives, I believe, 100 b.m.e.p., and it is also interesting to consider the figure of 91 b.h.p. obtained by Mr. Ashby in 1934 from an unsupercharged 1,100-c.c. Riley, with a compression ratio of only 10 to 1. Engines with poor or deliberately restricted breathing respond the most favourably to supercharging, relative to their former performances.
The use of three cylinders, either in line or radial, is sound practice. The flat twin, used in the Gregoire, is remarkably smooth and free from vibration for its type, but, as we all know, the range of smoothness of an engine increases with the number of cylinders it possesses. The lighter a car is the more unfavourable is the ratio between the gross weight and the mass of the reciprocating parts, worsening the case for few cylinders.
On the score of air cooling an in-line three-cylinder engine I, would draw readers’ attention to the existence of new Danish-made Nimbus motor-cycles. The four-cylinder, air-cooled power units have o.h.c. and develop 24 b.h.p. I recently observed these in Copenhagen and noticed particularly the lack of finning about the cylinder head and the fact that there were no air scoops. It seemed rather that the pressed frame shielded the engine from the air flow. They were relatively silent, and seemed smooth. D. P.
The letter from Mr. Monkhouse in your April issue is of interest because he appears to be labouring under the same misapprehension as I did myself prior to the war.
I first learnt that I had been credited with holding the Lewes 1,500-c.c. record from the Light Car of March 16th, 1940. Knowing that Mr. Monkhouse had bettered my time on a car of similar capacity, I wrote to the Editor of the Light Car, pointing out the apparent error, only to find that under the prevailing ruling I really was credited with holding the record.
The explanation is found in the reply, published in the Light Car of March 23rd, 1940, to my letter, and reads as follows: ” … the point is, however, that Monkhouse put up his best-ever time when running in the 2-litre class, which still leaves Mortimer the fastest 1 1/2-litre class man, and therefore the 1 1/2-litre class record holder.”
In view of the circumstances, the record is not one that I am particularly proud to hold and I have, in fact, never previously claimed it.
Mr. Monkhouse was certainly “quick to reply,” but I should not like him to think that I had claimed the record without being sure or the facts.
I am, Yours. etc.,
I was glad to see your note referring to “a write-up of some of the ‘now-forgotten’ cars” which appeared after the letter front Graham Dix.
I sometimes wonder if the present-day motorist would be astonished at the performances of some cars such as Seneschal, 9-h.p. 4-cylinder o.h.v., a really snappy and excellent performer; the Vernon Derby ”Ruby” or Chapuis Dornier editions, “Subaisse” Amilcars, the twin-cam 1,100 Salmson, to quote, four, all of the 1,100-c.c. class and excellent performers by present. standards. Even now, twenty years later, sports-car enthusiasts still return for another look. Going to larger classes, what of the Ansalsdo (2-litre sports tourer), Diatto, the “Alpine” Steyr, Metallurgique and the later but still forgotten Imperia, with its slide-valve engine?
Sounds as if !’m “foreign” car conscious, so I’ll ask again, what of the North Lucas saloon, with it radial air-cooled engine, of the utility style but sound Rover with flat-twin engine air-cooled 8-h.p., or the A.B.C., yet another excellent flat-twin?
Others of interest might be the friction-drive G.W.K., or that intriguing museum piece, the Lafayette, with, I believe, a 3-cylinder radial, air-cooled: the whole engine tipped bodily as one changed gear position in the range of it friction drive ratios. Yet another was the Constantinesco, with its automatic and almost infinitely-variable gearbox; how many average motorists know much of these; just a selection which have come to my mind as creations of the 1920’s?
I am, Yours, etc.,
[Yes, we remember, and honour, them all. – Ed.]
Here is another reader looking for assistance through your letter department.
I own what is supposed to be the only modified Brescia Bugatti in the U.S.A.(?). This winter I plan to completely rebuild the car, concentrating on the engine and transmission. My problem, of course, is obtaining advice and the required parts. The reconstruction job will include new valve guides, bearings, H.C. pistons, two-carburettor manifold, transmission gears, and other odd parts such as wheels, brake drums, etc. I suppose it would be hoping too much to look for a full Brescia engine or block?
Perhaps you have a reader who would give me much-needed advice, or who would refer me to the possessor of the required parts? I would also like any Bugatti handbooks or literature.
Possibly some of you readers might like to swop car photographs across the Atlantic? Thank you.
I am, Yours, etc.,
Paul J. Tiommins.
527 Broadway, S. Boston,
[Can anyone help? – Ed.]
May I suggest that the Vintage Sports Car Club and the organisation Mr. Robson may bring into being have entirely different functions.
As the owner of a very ancient Lambda I propose to support Mr, Robson’s venture with the hope that the service rendered in the shape of the record of cars and spare parts and the data acquired by years of experience of numbers of enthusiasts will help to keep many of the old favourites on the road. On the other hand, I am confident that this support will in no way take from the pleasure I enjoy through being a member of the V.S.C.C., nor in any way weaken that admirable “clearing house,” as Mr. Clutton likes to call it.
I am, Yours, etc.,
J. A. Earle Marsh.
I hasten to compliment you upon your vigorous and outspoken denunciation of that immeasurable disgrace – the rape, sale and extinction of Brooklands.
I am, Yours, etc.,