FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1934
1934 - 1425.PDF
MAY 31, 1934 37 THE AIRCRAFT ENGINEER SUPPLEMENT TO FLIGHT The jacket losses are increased by offsetting the plug, but in the optimum swirl region the difference is negligible. The head losses are about 25 per cent, of the cylinder losses and vary with swirl in the same manner. This ratio does not, however, necessarily represent the pro- portion in which the head and cylinder receive heat from the gases, for experience indicates that there is a good heat-flow path from head to cylinder via the head-rings and sleeve. iSeries D. Detonation Tests at 1,300 r.p.rn. (Fig. 11). —As stated above, tests were made by two methods, the first that of throttling, and the second that of fuel mixtures. Both methods show minimum detonation with a swirl of 1.5-2.0, or practically the same value as the optimum for power and efficiency. The total range of requirements in fuel quality is, however, not great, the extreme difference being only one " octane number." Incidentally, it appears that this engine is very sensi- tive to the fuel quality as far as audible detonation is concerned, a difference of 0.1 octane number being distinguishable by ear, but, on the other hand, it does not suffer seriously from the secondary effects which normally render detonation dangerous. Thus the jacket heat loss is not appreciably increased by detonation, and there is no tendency to pre-ignition with any reasonable degree of detonation. These characteristics were, incidentally, also shown by a similar air-cooled sleeve-valve unit, which could run continuously with a really alarming intensity of detonation. The path of the detonation noise is affected by the swirl varying from the usual " pink " at low swirl ratios to a dull thud with high swirl. (To be concluded) INVESTIGATION INTO THE VARIA TION OF ENGINE POWER WITH HEIGHT By W. R. ANDREWS, A.F.R.Ae.S.* (Concluded from p. 31) A similar treatment is given to the alternative form of the power law of equation 10, when /a = 0-0674, so that Pe = 1-0674 P (1-5 -0-5 T) - 0-0674 . . . (14) Tables 4 and 5 give the characteristics and calculation of N \/<7 corresponding to Tables 2 and 3. The plotted value corresponding to Fig. 3 are given in Fig. 4. It is at once apparent from Table 5 that the correction for temperature quickly increases with height, and does not • Mr. Andrews is on the Technical Staff of A. V. Roe & Co., Ltd. TABLE 4 P;. = 1-0674 P(1.5 _ o-5 T) - 0-0674 Height Hfeet a P a P.: V!In . i— Equivalent Standard Height HE TT IT Xlfi — xlg= AH Standard Temperature 0 ... 5,000 ... 10,000 ... 15,000 ... 20,000 ... 25,000 ... 30,000 ... 1-0 0-8616 0-7384 0-6291 0-5327 0-4480 0-374 10 0-836 0-6921 0-566 0-4567 0-3625 0-2821 10 1031 1-067 1-111 1167 1-236 1-325 1-219 1-257 1-301 1-355 1-423 1-507 1-615 1-0 0-9282 0-8593 0•7932 0-7298 0-6693 0-6115 0-915 0-838 0-763 0-6913 0-622 0-5555 0-4920 — — —- — — — -— — — — — — — — Standard Temperature + 30° 0 ... 5,000 ... 10,000 ... 15,000 ... 20,000 ... 25,000 ... 30.000 ... 0-9055 0-7775 0-6640 0-5635 0-4754 0-3980 0-3306 0-9444 0-7804 0-6365 0-5104 0-4011 0-3065 0-2265 0-959 0-996 1-0435 1-104 11855 1-299 1-460 1-169 1-214 1-272 1-347 1-445 1-585 1-780 0-9516 0-8818 0-8149 0-7507 0-6895 0-6311 0-5750 0-887 0-8075 0-731 0-656 0-5835 0-512 0-442 1,800 7,050 12,250 17,650 22,900 28,400 34,000 1,800 2,050 2,250 2,650 2,900 3,400 4,000 Standard Temperature — 30° 0 ... 5,000 ... 10,000 ... 15,000 ... 20,000 ... 25,000 ... 30,000 ... 1116 0-9655 0-8315 0-712 0-606 0-5125 0-4305 1-0556 0-8916 0-7477 0-6216 0-5123 0-4181 0-3377 1-056 1-083 1-1125 1146 1-183 1-226 1-275 1-288 1-321 1-357 1-397 1-4425 1-495 1-555 1-0565 0-9876 0-9129 0-8438 0-7785 0-7159 0-6561 0-943 0-866 0-7955 0-7255 0-6595 0-5965 0-537 3,100 7,850 12,600 17,400 21,950 26,500 . - 1,900 - 2,150 - 2,400 — 2.600 - 3#50 - 3,500 540 e
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
