OPINIONS FROM OTHERS
Page 20
If you've noticed an error in this article please click here to report it so we can fix it.
Editor invites correspondence on all sub jects,connected with the use of conimerci:al motors. Letters should be on one . of the paper only and typewritten by preference. The riht of abbreviation is reserved, and no respcnisibility for views expressed is accepted.
The side
Steam Road Haulage in France.
The Editor, THE COMMERC1PL MOTOR.
[1679] Sir,—We are largely engaged in the manufacture of steam road engines, so that we are interested in the heavy type which your contributor refers to under Class A. So far as we, or any other manufacturers, are concerned your contributor gives us no assistance, either how to discover the weaknesses which he observed, or to correct them in the future.
Amongst the many engines of this ,type sent tint, some failures were inevitable. It would have been interesting, and it would have had an educative value if we hail been told what percentage of the engines failed from breakage of steerage brackets, soft cross strakes, and broker spokes, diseriminating between those which failed from inherent bad design and those which failed as the result of accident. It is conceivable that some of the breakages were due to this latter cause, such as running into a stone wall, or overturning in a ditch. These contingencies are not provided for in settling the strength of the various parts.
We are not experts in motor wagons, which are dealt with under Class B, but a perusal of the article inclines us to think that in this case also your contributor argues from the particular to the general ; and he gives us no idea of the extent of his observations, and the proportion of the total rolling stock to which it applies.—Yours faithfully, For J. AND H. MCLAREN, LTD., Leeds. J. MCLAREN, Direttor.
The Editor, THE COMMERCIAL MOTOR.
[1680] Sir,—As, we believe, the " Sentinel was the only under-type vehicle adopted by the British or other Governments during the war, it is apparcut that your contributor's remarks on under-type .steare wagons concern this make.
Since your contributor refers only to end-tipping under-type wagons, it is evident that he came into touch with only a very few of the several hundreds of " Sentinel " steam wagons employed in the various war areas. Only about 15 per cent, of the "Sentinel" wagons used by the British Government were of the end-tipping type and none of those used by the Belgian and French authorities were end-tipping. All of the others were of the standard fixed body type and of six tons capacity.
Your contributor's remarks suggesting that special fuel is required for " Sentinel" wagons, or that their range of useful fuels is very limited are rather extraordinary and point to a very superficial knowledge of the steaming capacity of the Sentinel " boiler, since it is appreciated by every user of both types in this country and abroad that the "Sentinel" has a far wider fuel range than any over-type vehicle, and can steam on qualities of,fuel which would be quite impossible for use in the ordinary steam wagon locomotive type boiler. It is, for instance, not necessary to riddle out the dust when using ordinary coal on a "Sentinel" boiler, although such a precaution is quite essential to good steaming on the over-type vehicle. Your contributor's suggestion, therefore, that the facts are the other way about is decidedly nissleading and, we feel, must be based upon a mis s.48 understanding, or inaccurate reports he has received. It is quite true that the " Sentinel" boiler is designed for the efficient use of coke fuel, which locomotive type boilers cannot efficiently use, but this does not prevent the " Sentinel" boiler from using equally well steam coal or -other grades which can be used'-by any other type of steam wagon.
We have never, heard of a single complaint from any of the governments concerned with the hundreds of " Sentinel" wagons supplied, with regard to any trouble whatever with the fire-box tubes and if your contributor is referring to a specific case, such trouble could only be due:to gross and unjustifiable neglect on the part of those in charge of the vehicle in not taking the ordinary trouble to keep the boiler firebox reasonably clean. It is in no wise right to suggest that the design of the wagon is in any 'way to blame for the results of such appalling neglect which would be necessary to cause the state of dirt which your contributor describes.
We are very interested in the article generally and are pleased to have this corroboration of reports we have already had from other areas where " Sentinels" were largely used, of the extraordinary rarity of mechanical troubles with " Sentinel'? wagons or breakages of any uarts.—Yours faithfully, THE " SENTINEL " WAGON WORKS, LTD. Shrewsbury.
The Waste of Power.
The Editor, THE COMMERCIAL MOTOR.
[1681] Sir,—In your issue of April 3rd "Pertinax" raises the question of the recovery of the heat lost to the exhaust in internal-combustion engines, and, so far as I can see,. his calculation would appear to be accurate. Evidently, if only 1 lb. of steam is available per b.h.p. hour, not much can be accomplished in that direction.
Would it not be better, however, to set to work from the cooling water standpoint? After all, as your contributor showed in the article "The Waste of Power," published in your issue of March 27th, more heat is lost to the jacket than to the exhaust. I have heard of proposals for maintaining the jacket at a, fixed temperature, by filling it with steam at a constant pressure, instead of with water. The jacket could then be inseries with a boiler, and the heat units passing to the jacket could be utilized for raising some of 'the steam in this jacket-cum-boiler system. Provided that a suitable use for this steam could be found, the waste of such heat units would be obviated.
But here there arises a difficulty. Suppose 'the pressure in the jacket were constant at, say, 300 lb. Then the jacket temperature would be :— Could some of your readers enlighten me as. to whether this temperature would not be too high to permit an internal-combustion engine to function normally ?—Yours faithfully, ARCHANGEL.