From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Wind tunnel test results and calculated performance figures for a 3 1/2 Litre Bentley model.
| Identifier | ExFiles\Box 160\2\ scan0168 | |
| Date | 30th January 1933 guessed | |
| WIND TUNNEL TESTS. 3 1/2 LITRE BENTLEY. FIGURES FOR MODELS IN TUNNEL. POSSIBLE CAR PERFORMANCES. TABLE: Headers: TEST, FRONT WINGS, REAR WINGS, SCREEN, RADIATOR, TAILS, BODIES, STEPS, FLAT PLATE TUNNEL DRAG IN LBS., CORRESP. DRAG REFLEXION METHOD, REFLEX WITH DRAG IN LBS, THEORETICAL DRAG ON CAR AT 88.0 M.P.H IN LBS, PROJECTED AREA IN SQ. FT., K FROM THEORETICAL TUNNEL DRAG, REMARKS, DRAG AT 80 M.P.H IN LBS (COMPUTED), K BASED ON STD. SALOON - SEE APPENDIX, 1/2 MILE SPEEDS STD. SAL., LAP SPEEDS., MAX. ROAD SPEED. Row 1: Test=1, Front Wings=NIL, Rear Wings=NIL, Screen=17° VERT, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=NIL, Flat Plate Tunnel Drag=1.0929, Corresp. Drag Reflexion=1.243, Reflex with Drag=, Theoretical Drag=257.5, Projected Area=21.70, K=.00130, Remarks=, Drag at 80mph=312.0, K Based on Std Saloon=.001805, 1/2 Mile Speeds=93.7, Lap Speeds=89.7, Max Road Speed=98.7 Row 2: Test=2, Front Wings=NIL, Rear Wings=STD. NO OUTSIDE, Screen=17° VERT, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=NIL, Flat Plate Tunnel Drag=1.0871, Corresp. Drag Reflexion=1.236, Reflex with Drag=, Theoretical Drag=256.0, Projected Area=23.4, K=.00146, Remarks=, Drag at 80mph=311.0, K Based on Std Saloon=.00180, 1/2 Mile Speeds=94.0, Lap Speeds=90.0, Max Road Speed=99.0 Row 3: Test=3/B, Front Wings=VALANCE STD. WITH OUTSIDE, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2442, Corresp. Drag Reflexion=1.415, Reflex with Drag=, Theoretical Drag=292.8, Projected Area=23.4, K=.00169, Remarks=Z. THIS IS A COMPUTED TEST, Drag at 80mph=356.0, K Based on Std Saloon=.00206, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 4: Test=4, Front Wings=VALANCE STD. NO OUTSIDE, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2355, Corresp. Drag Reflexion=1.402, Reflex with Drag=, Theoretical Drag=291.0, Projected Area=23.4, K=.00168, Remarks=BY TAKING THE DIFFERENCE IN, Drag at 80mph=353.0, K Based on Std Saloon=.00204, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 5: Test=5*, Front Wings=VALANCE. FLARED WITHOUT, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2514, Corresp. Drag Reflexion=1.422, Reflex with Drag=, Theoretical Drag=294.2, Projected Area=23.4, K=.001695, Remarks=SPARE WHEEL OUTSIDE, DRAG BETWEEN No. 25 & 26 &, Drag at 80mph=356.5, K Based on Std Saloon=.00206, 1/2 Mile Speeds=89.7, Lap Speeds=85.7, Max Road Speed=94.7 Row 6: Test=6, Front Wings=MUDLIP FLARED WITH, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2254, Corresp. Drag Reflexion=1.393, Reflex with Drag=, Theoretical Drag=288.5, Projected Area=23.4, K=.001668, Remarks=ADDING IT TO No. 2., Drag at 80mph=350.0, K Based on Std Saloon=.00202, 1/2 Mile Speeds=90.6, Lap Speeds=86.6, Max Road Speed=95.6 Row 7: Test=7, Front Wings=MUDLIP, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2525, Corresp. Drag Reflexion=1.423, Reflex with Drag=, Theoretical Drag=294.5, Projected Area=23.4, K=.00170, Remarks=, Drag at 80mph=358.0, K Based on Std Saloon=.00207, 1/2 Mile Speeds=89.6, Lap Speeds=85.6, Max Road Speed=94.6 Row 8: Test=8, Front Wings=BROWNING (O.E.), Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=NO, Flat Plate Tunnel Drag=1.3055, Corresp. Drag Reflexion=1.482, Reflex with Drag=, Theoretical Drag=307.0, Projected Area=23.4, K=.00177, Remarks=, Drag at 80mph=373.0, K Based on Std Saloon=.00216, 1/2 Mile Speeds=88.6, Lap Speeds=84.6, Max Road Speed=93.6 Row 9: Test=9, Front Wings=PANHARD TYPE, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2212, Corresp. Drag Reflexion=1.390, Reflex with Drag=, Theoretical Drag=288.0, Projected Area=22.87, K=.00170, Remarks=, Drag at 80mph=350.0, K Based on Std Saloon=.00202, 1/2 Mile Speeds=90.6, Lap Speeds=86.6, Max Road Speed=95.6 Row 10: Test=Z, Front Wings=CYCLE TYPE, Rear Wings=STD., Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=NO, Flat Plate Tunnel Drag=, Corresp. Drag Reflexion=1.348, Reflex with Drag=, Theoretical Drag=280, Projected Area=22.18, K=.00171, Remarks=PROPORTIONALLY DERIVED FROM, Drag at 80mph=340.0, K Based on Std Saloon=.00197, 1/2 Mile Speeds=91.3, Lap Speeds=87.3, Max Road Speed=96.3 Row 11: Test=12, Front Wings=STD. NO OUTSIDE VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=25°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2438, Corresp. Drag Reflexion=1.415, Reflex with Drag=, Theoretical Drag=293.0, Projected Area=23.4, K=.00169, Remarks=THE FACT THAT THE STANDARD SALOON (CORRESPONDING TO TEST No 5), Drag at 80mph=355.0, K Based on Std Saloon=.002055, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 12: Test=13, Front Wings=VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=35°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2377, Corresp. Drag Reflexion=1.405, Reflex with Drag=, Theoretical Drag=291.0, Projected Area=23.4, K=.00168, Remarks=WITH 92.5 H.P AT ROAD WHEELS AT 4150 R.P.M., Drag at 80mph=353.0, K Based on Std Saloon=.00204, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 13: Test=13A, Front Wings=VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=45°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2416, Corresp. Drag Reflexion=1.411, Reflex with Drag=, Theoretical Drag=292.0, Projected Area=23.4, K=.001685, Remarks=LAPS BROOKLANDS AT 86 M.P.H & DOES FLYING, Drag at 80mph=354.0, K Based on Std Saloon=.00204, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 14: Test=16A, Front Wings=VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=17°, Radiator=LONG, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2600, Corresp. Drag Reflexion=1.431, Reflex with Drag=, Theoretical Drag=296.1, Projected Area=23.4, K=.00171, Remarks=1/2 MILE AT 90 M.P.H. MAX ROAD SPEED, Drag at 80mph=359.0, K Based on Std Saloon=.002080, 1/2 Mile Speeds=89.7, Lap Speeds=85.7, Max Road Speed=94.7 Row 15: Test=16B, Front Wings=VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=25°, Radiator=LONG, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2565, Corresp. Drag Reflexion=1.427, Reflex with Drag=, Theoretical Drag=295.4, Projected Area=23.4, K=.00170, Remarks=94 M.P.H. AXLE RATIO = 4.1 to 1., Drag at 80mph=358.0, K Based on Std Saloon=.00207, 1/2 Mile Speeds=89.7, Lap Speeds=85.7, Max Road Speed=94.7 Row 16: Test=16C, Front Wings=VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=35°, Radiator=LONG, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2578, Corresp. Drag Reflexion=1.428, Reflex with Drag=, Theoretical Drag=295.5, Projected Area=23.4, K=.00170, Remarks=, Drag at 80mph=358.0, K Based on Std Saloon=.00207, 1/2 Mile Speeds=89.7, Lap Speeds=85.7, Max Road Speed=94.7 Row 17: Test=16D, Front Wings=VALANCE, Rear Wings=STD. NO OUTSIDE, Screen=45°, Radiator=LONG, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2446, Corresp. Drag Reflexion=1.415, Reflex with Drag=, Theoretical Drag=293.0, Projected Area=23.4, K=.00169, Remarks=, Drag at 80mph=355.0, K Based on Std Saloon=.002055, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 18: Test=17, Front Wings=PANHARD TYPE, Rear Wings=STD. NO OUTSIDE, Screen=35°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.2413, Corresp. Drag Reflexion=1.412, Reflex with Drag=, Theoretical Drag=292.5, Projected Area=23.4, K=.00169, Remarks=MAX. ROAD SPEED = 1/2 MILE SPEED +5., Drag at 80mph=354.8, K Based on Std Saloon=.002053, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 Row 19: Test=19, Front Wings=NIL, Rear Wings=PANHARD - SEE NOTE ø, Screen=45°, Radiator=LONG, Tails=, Bodies=STD SALOON, Steps=NO, Flat Plate Tunnel Drag=.8982, Corresp. Drag Reflexion=1.020, Reflex with Drag=, Theoretical Drag=211.2, Projected Area=23.4, K=.00122, Remarks=REVERSED, 1/2 MILE SPEED = LAP SPEED +4., Drag at 80mph=257.0, K Based on Std Saloon=.001485, 1/2 Mile Speeds=100, Lap Speeds=96.0, Max Road Speed=105.0 Row 20: Test=20, Front Wings=NIL, Rear Wings=PANHARD - SEE NOTE ø, Screen=35°, Radiator=LONG, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.1028, Corresp. Drag Reflexion=1.252, Reflex with Drag=, Theoretical Drag=259.5, Projected Area=23.4, K=.00150, Remarks=MODEL, Drag at 80mph=314.0, K Based on Std Saloon=.00182, 1/2 Mile Speeds=93.5, Lap Speeds=89.5, Max Road Speed=98.5 Row 21: Test=21, Front Wings=STD WITH OUTSIDE, Rear Wings=PANHARD - SEE NOTE ø, Screen=17°, Radiator=SHORT, Tails=, Bodies=STD SALOON, Steps=YES, Flat Plate Tunnel Drag=1.1922, Corresp. Drag Reflexion=1.357, Reflex with Drag=, Theoretical Drag=281.0, Projected Area=23.4, K=.00162, Remarks=, Drag at 80mph=341.0, K Based on Std Saloon=.00197, 1/2 Mile Speeds=91.2, Lap Speeds=87.2, Max Road Speed=96.2 Row 22: Test=24, Front Wings=VALANCE. B, Rear Wings=STD., Screen=17° VERT, Radiator=SHORT, Tails=, Bodies=STO. SALOON, Steps=NO, Flat Plate Tunnel Drag=, Corresp. Drag Reflexion=1.400, Reflex with Drag=, Theoretical Drag=291.0, Projected Area=23.4, K=.00168, Remarks=, Drag at 80mph=353.0, K Based on Std Saloon=.00204, 1/2 Mile Speeds=90.0, Lap Speeds=86.0, Max Road Speed=95.0 NOTES: B. TEST No. 3 & TEST No. 24 ARE THE SAME THE FORMER USING THE FLAT PLATE METHOD & BEING JUST 88% OF No. 24 BY THE REFLEX METHOD. * STD. SALOON 2 B. 3. ø PANHARD WINGS SLOPING RADIATOR & THE WHOLE FRONT FILLED IN WITH PLASTACINE. | ||