FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1919
1919 - 1560.PDF
TABLE VA—Observed Horse-Powers, R.P.Ms, and Barometric Pressures for X Fuel, Series 99 to in Horse-Powers corrected to Standard Temperatures Approximate Altitude = 5,500 ft. 99 100 101 105 106 no in Av. DECEMBER 4, 1919 TABLE VB.— Observed Horse-Powers, R.P.Ms, and Barometric Pressures for X Fuel, Series 99 to in Horse-Powers corrected to Standard Temperatures Approximate Altitude = 19,200 ft. 02 61 62 02 62 61 61 62' 1 ft en h.p. •8 ft en 1310 1325 1300 1375 1365 1305 1315 119- 126' 114 124 122 118 116 1504 1515 1518 1525 1536 1480 1485 h.p. ed. ft en h.p. i ft en h.p. 0 ft en h.p. 141' 147. 135 141 140 i39 i37 1710 1715 1715 1725 1763 1695 1700 1328 120-3 1509 140-5 1718 Approximate Altitude 158' 162 • 154' 158 153 159 157 1923 1935 1920 1965 1925 1890 1910 168 173 165 173 165 171 171 157-5 1924 leg 's 11,500 ft. 2110 2140 2155 2140 2140 2120 2156 174-2 181 o 177 179 174 182 181 82137178-4 Tes t No . 99 100 101 105 106 no in Av. • v> U Ui 37-6 37-5 37-8 37-7 37-5 37-5 37-6 37-6 Speed . 1300 1310 1310 1355 1360 1289 1310 1319 h.p. 71-2 71-7 69-4 71-4 72-8 74-0 71-1 71-7 1 Sp e 1500 1500 1520 1528 1515 1513 1487 1509 h.p. 84-6 »3-3 81-o 82-3 82-6 88-3 82-8 83-6 13 B Sp e 1715 1720 1725 1725 1745 1718 1717 1724 h.p. 95-2 95-° 88-9 90-6 91-7 96-7 94-2 93-2 1 Sp e 1920 1920 1940 1923 J925 1896 1910 1919 h.p. 100-6 995 95-6 98-4 98-6 99-4 101 -9 99-1 % Sp e 2100 2135 2120 2140 2140 2100 2125 2123 h.p. 103-3 107-0 98-5 105-4 102-5 105-7 105-2 103-9 Approximate Altitude = 29,600 ft. 99 100 IOI 105 106 110 in Av. 49-90 49-80 49-90 50-20 49-80 49-80 49 95 49-9 1310 1315 1315 !340 1370 1327 i3°5 96' 96 93 95 96 101 92 1517 1500 1505 1515 1540 1540 1500 114 "3 109 no in 119 in 1715 1725 1730 1715 1750 1710 *737 127-0 126-7 118 124 120 130 126 1907 1930 1925 1910 1945 1915 1927 T34 138 127 J34 130 138 ^37 2105 2115 2107 2135 2150 2120 2130 139-5 143-0 133-2 140-5 135-0 144-8 144-5 99 100 IOI 105 106 lie III Av. 25-7 25-5 26-0 25-9 25-7 25-7 25-7 25*7 1303 1330 1314 1310 i37o 1290 1310 1318 47-7 48-4 45-1 47*3 47-6 48-2 51-2 47-9 1535 1505 1512 1505 1560 1510 1S05 I5J9 56-6 55-8 52-9 55-8 54-4 57-2 59-1 56-0 1730 1725 1707 1705 1735 1723 1710 1719 61-4 61-8 5«-3 61-4 59-6 63-6 65-7 61-7 1930 1930 1924 1914 1885 1900 1937 1917 62-6 64-4 62 -4 65-9 6o-8 64-8 69-9 64-4 1326 96-21517112-8 1726 124-9 1923 134-5 2123 140-1 TABLE VI.—Table of Data for Averaging Horse-Powers for High-Compression from Series 67 to 79 and 99 to in Horse-Powers corrected to Standard Temperatures 2105 2105 2120 2115 2085 2I20 2I30 2112 65-1 64-1 63-1 68-8 60-8 63-2 72-0 65-3 A—Averages from Table IV. Average of Nine Tests, Series from 67 to 79 Bar. Press. 62-1 49-8 37-6 25-6 h.p. 137-7 no-8 82-6 54-o B—Averages from Tables VA and VB. Average of Seven Tests, Series from 99 to in Bar. Press. 62-0 49-9 37-6 25-7 h.p. 140-0 III -O 82-8 55-3 C—Averages from A and B. Average of 16 Tests, Series from 67 to 79 and 99 to in Bar. Press. 62-05 49-85 37-60 25-65 h.p. 138-9 110-9 82-7 54-65 being on the high-compression ratio 5-3. The averaged data are plotted in Fig. 6, together with the corresponding data for the other two compressions (4-7 and 6-2) obtained from the last column of Table IV, giving curves of horse power at 1,500 r.p.m. corrected to standard temperatures versus barometric pressure for the three compressions. From these curves the ratios of the different horse-powers for each compression to the horse-power at sea level for the high (5-3) compression were computed. These ratios were plotted in curve, Fig. 7, against altitudes in feet corresponding to the different barometric pressures. The altitudes were computed from the formula : 76 h - 62900 log 10 j obtained from the Smithsonian Meteorological Tables for 1907, page 100, in which k is the altitude in feet, and p is the atmospheric pressure in centimetres of mercury. The curves in Fig. 8 illustrate the variation in horse-power with compression ratio at different altitudes. The horse-power developed with the 5-3 or " high " com pression ratio, at the different altitudes, was taken as 100 per cent., and the other two compression ratios were plotted as percentages of this curve. As will be seen upon examina tion, the gain in horse-power due to " extra-high " over " high " compression amounts to but 2 -8 per cent, at 5,000 ft., while it increases to nearly 5 -8 per cent, at 30,000 ft. Like- Re-Opening of Recruiting for the R.A.F. OWING to the large number of men who are due for discharge on the completion of their engagements, recruiting for the R.A.F. has now been re-opened and there are vacancies for skilled mechanics of various trades. Engagements are for 4, 6 or 8 years with the Colours, with 8, 6 or 4 years respectively with the reserve. In view of the newly-revised rates of pay of the Force, the openings are distinctly attractive, particularly as men will be working at their own trades and constantly gaining fresh wise the decrease in horse-power due to " low " compression, while only 3 -3 per cent, at 5,000 ft., amounts to about 7 -3 per cent, at 30,000 ft. It is evident, therefore, that the value of high compression is more apparent at high than at low altitudes. It should be pointed out that any comparison of absolute horse-powers for the different compression ratios may be misleading, as the engine conditions, such as fit of piston and rings, condition of valves, etc., were not the same in each case. However, the manner in which the horse-power varies with barometric pressure in each case may be taken as characteristic for the given combination of engine, car burettor, and fuel with a given compression ratio. In conclusion, it may be stated that practically all the tests conducted in the Altitude Laboratory have a nearly equal bearing on the relation of horse-power to altitude. Any given set of conditions, which affect the operation of the engine, may be held approximately constant during one test, and the variation of horse-power with altitude deter mined for these conditions. Only a small amount of this information has been collected in this report, as 'the tests upon which it is based were chosen particularly to show the power-altitude relation at different compression ratios. • Supplementary reports will be issued as additional informa tion becomes available either as the result of experiments already completed or ones to be carried out in the future. experience which will be of great value to them on their return to civil life, by which time in all probability there will be a greatly increased demand for aircraft workers of all categories. Skilled aircraft workers who are at present unemployed, of those who are not employed in their own trades, would, therefore, be well advised to consider the possibilities of the careers offered by the Service. Full details as to pay, etc., may be obtained from 4, Hen rietta Street, London, W.C., or from any R.A.F. station. 1562
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
