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Miss Shilling's orifice

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engines and did not suffer from this problem as injection pumps kept fuel at constant pressure. German pilots could exploit this by pitching steeply forward while opening the throttle, a manoeuvre that pursuing British aircraft would be unable to emulate. The British countermeasure, a half roll so
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manoeuvre (pitching the nose hard down), fuel was forced up to the top of the carburettor's float chamber rather than down into the engine, leading to loss of power. If the negative G continued, fuel collecting in the float chamber would force the float to the floor of the chamber. Since this float
143:, invented a simple device which could be fitted without taking the aircraft out of service. She designed a thimble-shaped brass flow restrictor with precisely calculated dimensions to allow just enough fuel flow for maximum engine power. It came in two versions, one for 12 163:
inverted V12 powerplant had utilised fuel injection since 1937. During early 1941, Shilling travelled with a small team to fit the restrictors in one RAF base after another, giving priority to front-line units. By March 1941 the device had been installed throughout
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While not completely solving the problem, the restrictor, along with modifications to the needle valve, permitted pilots to perform quick negative G manoeuvres without loss of engine power. This improvement solved the drawback of the RAF's
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manifold pressure and another for the 15 psi achieved by supercharged units. The design of the thimble-shaped flow restrictor was later refined to a simplified flat brass washer.
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This simple measure was only a stopgap: it did not allow inverted flight for any length of time. The problems were not finally overcome until introduction of the
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the aircraft would only be subjected to positive G as it followed German aircraft into a dive, could take enough time to let the enemy escape.
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The Rolls-Royce Merlin engine originally came with a direct carburettor, prone to cut-out due to fuel flooding in negative G.
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was a very simple technical device created to counter engine cut-outs experienced during negative G manoeuvres in early
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with an over-rich mixture. The consequent rich mixture cut-out would shut down the engine completely.
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controlled the needle valve that regulated fuel intake, the carburettor would flood and drown the
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Cracking the Zero Mystery: How the U.S. Learned to Beat Japan's Vaunted WWII Fighter Plane
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Complaints from pilots over engine cut-out during dives and brief
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led to concentrated search for a solution. Engine manufacturer
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produced an improved carburettor, but this failed in testing.
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explaining the Merlins carburettor and the Tilly orifice
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Fuel flow restrictor retro-fitted to Merlin engines
294:Koga's Zero: The Fighter That Changed World War II 62:, it was referred to under various names, such as 369: 341:Negative Gravity, the Life of Beatrice Shilling 86:engine came equipped with dual-choke updraught 257:. Marlborough, Wiltshire: Airlife Publishing. 225:Negative Gravity: A Life of Beatrice Shilling 222: 77: 255:British Piston Engines and their Aircraft 31: 290: 252: 210: 14: 370: 276:. London: Arms and Armour Press Ltd. 271: 198: 118: 155:-powered fighters versus the German 378:Rolls-Royce aircraft piston engines 24: 334: 274:The Spitfire Story: Second edition 227:. England: Charlton Publications. 25: 389: 355: 216: 204: 192: 70:in reference to its inventor, 13: 1: 223:Freudenberg, Matthew (2003). 185: 135:, an engineer working at the 137:Royal Aircraft Establishment 7: 10: 394: 343:, by Matthew Freudenberg ( 245: 112:gasoline direct injection 72:Beatrice "Tilly" Shilling 311:Originally published as 58:. Officially called the 78:Engine cut-out problems 41:Miss Shilling's orifice 272:Price, Alfred (1986). 253:Lumsden, Alec (2003). 110:, German fighters had 82:Early versions of the 64:Miss Tilly's diaphragm 54:aeroplanes during the 37: 291:Rearden, Jim (1995). 35: 180:pressure carburettor 157:Messerschmitt Bf 109 141:Farnborough Airfield 166:RAF Fighter Command 161:Daimler-Benz DB 601 170:Sir Stanley Hooker 153:Rolls-Royce Merlin 119:The RAE restrictor 84:Rolls-Royce Merlin 38: 323:978-0-8117-2235-3 133:Beatrice Shilling 108:Battle of Britain 60:R.A.E. restrictor 56:Battle of Britain 16:(Redirected from 385: 327: 308: 287: 268: 239: 238: 220: 214: 208: 202: 196: 104:Battle of France 92:negative G force 21: 393: 392: 388: 387: 386: 384: 383: 382: 368: 367: 358: 337: 335:Further reading 332: 324: 312: 305: 284: 265: 248: 243: 242: 235: 221: 217: 209: 205: 197: 193: 188: 159:E machine. The 125:inverted flight 121: 80: 28: 23: 22: 15: 12: 11: 5: 391: 381: 380: 366: 365: 357: 356:External links 354: 353: 352: 336: 333: 331: 330: 329: 328: 322: 303: 288: 282: 269: 263: 249: 247: 244: 241: 240: 234:978-0954616502 233: 215: 203: 190: 189: 187: 184: 120: 117: 88:SU carburettor 79: 76: 26: 18:RAE Restrictor 9: 6: 4: 3: 2: 390: 379: 376: 375: 373: 363: 360: 359: 350: 349:0-9546165-0-2 346: 342: 339: 338: 325: 319: 315: 310: 309: 306: 304:0-929521-56-0 300: 296: 295: 289: 285: 283:0-85368-861-3 279: 275: 270: 266: 264:1-85310-294-6 260: 256: 251: 250: 236: 230: 226: 219: 212: 207: 200: 195: 191: 183: 181: 178: 173: 171: 167: 162: 158: 154: 148: 146: 142: 138: 134: 130: 126: 116: 113: 109: 105: 100: 98: 93: 89: 85: 75: 73: 69: 68:Tilly orifice 65: 61: 57: 53: 50: 46: 42: 34: 30: 19: 340: 313: 293: 273: 254: 224: 218: 213:, p. 32 211:Lumsden 2003 206: 201:, p. 78 194: 174: 149: 122: 101: 97:supercharger 81: 67: 63: 59: 40: 39: 29: 129:Rolls-Royce 102:During the 199:Price 1986 186:References 182:in 1943. 49:Hurricane 372:Category 45:Spitfire 246:Sources 66:or the 52:fighter 347:  320:  301:  280:  261:  231:  177:Bendix 362:Video 345:ISBN 318:ISBN 299:ISBN 278:ISBN 259:ISBN 229:ISBN 106:and 47:and 145:psi 139:at 374:: 316:. 74:. 351:) 326:. 307:. 286:. 267:. 237:. 20:)

Index

RAE Restrictor

Spitfire
Hurricane
fighter
Battle of Britain
Beatrice "Tilly" Shilling
Rolls-Royce Merlin
SU carburettor
negative G force
supercharger
Battle of France
Battle of Britain
gasoline direct injection
inverted flight
Rolls-Royce
Beatrice Shilling
Royal Aircraft Establishment
Farnborough Airfield
psi
Rolls-Royce Merlin
Messerschmitt Bf 109
Daimler-Benz DB 601
RAF Fighter Command
Sir Stanley Hooker
Bendix
pressure carburettor
Price 1986
Lumsden 2003
ISBN

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