Gunspray.
Page 13
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A Petrol-economizing Device of Proved Merit.
Gunspray is a carburetting device which has been , before., us for some time. We have been, however, _ well aware that certain tests were being made by the Army Service Corps, and have delayed publication until the report of these tests came to hand. In the main, it is a device for enabling petrol engines to be started easily. It has been applied to practically every type of machine, not excepting aeroplane engines and heavy-vehicle engines. It is, perhaps, to large commercial motors that its application will be most useful, e5pecially on those having powerful engines which are somewhat difficult to start. It is really, a device for admitting finely atomized petrol and air into the induction pipe; If reference be made to the illustration which we reproduce, the majority of our readers will gather the means of its application. A short description, however, will be useful.
The small tank seen near the bottom of the detail_ of the device carries a store of petrol. Upon the starting handle being turned and a partial vacuum created in the induction pipe, some of this petrol is Rucked through the small vertical tube seen within the container, and along with it a stream of air which enters through the spindle of the plug. The arrangements of the jets from which the petrol and air issue is such that the petrol is very finely atomized, andlt forms a mixture which has proved to be successful for starting the most stubborn of engines. The illustrations are so clear that space need not be devoted to much descriptive matter. Control is from the dashboard, and on the switch there are three positions marked, one for starting, one a, neutral position in which the device is inoperative, and a third with the apertures so arranged that it allows of a little extra air being taken in with the mixture from the main carburetter but no petrol. It is necessary that this device be fixed betw,een the throttle valve and engine, so that all other air than that which enters
through the Gunspray is excluded. If it is not pus-) sible-to fitthe device in this position, other meanof excluding air must be provided. Generally a separate tank is supplied for fuel to the Gunspray, but it may alternatively be arranged to draw from the main tank.
Not only is Gunspray particularly useful for starting stubborn engines, but it may be used and supplied with petrol for starting while the main running . is done on a substitute or mixtures of petrol and some substitute.
• We have perused a, copy of the report which was submitted to the War Office by an officer of the Army Service Corps. The trials were carried out for a period of four weeks with four makes of lorries. In
• each case a vehicle was selected which under ordinary conditions gave considerable difficulty in starting. Crown brand petrol of a specific gravity of 735 was used. In all cases was the usual starting -difficulty entirely overcome. Owing to the fact that the trials were carried outain summer weather when conditions are not so severe as in winter, the officer making the test being wishful of imitating winter conditions so far as possible, packed the induction pipe and cylinders with a layer of ice for a period of two hours previous to making the test. The officer submits a number 'of figures and calculations which show that. in connection with his M.T. Company alone, if Gun•sprays were fitted througheut, an economy of £487 per month. would be effected during the winter months owing To the exclusion of the need for abnormal amounts of petrol for starting.