MEMORANDUM REPORT ON
Medium Bomber (B-26) Airplane, A.C. No. 40-1361
Subject: | Performance Test |
Section: | Flying Branch |
Serial No.: | PHQ-M-19-1184-A |
A. | Purpose | |
1. | Report on flight tests of Martin Medium Bomber (B-26) airplane equipped with two (2) Pratt-Whitney R-2800-5 engines and four-bladed constant speed propellers, blade design No. 814C03-18A, normal range 23° to 55° at 42" radius. Gross weight normal military load 26,734 lbs., c.g. wheels retracted 14.63% m.a.c. Landing gear retracted, wing flaps neutral, cowl flaps zero degrees, oil cooler flaps flush with cowling, carburetor cold, except where otherwise stated. Propellers equipped with cuffs, radio antenna in place, de-icer equipment not installed, airplane not camouflaged. |
B. | Test Results | |
1. | High speed, wide open throttles in high blower ratio, mixture controls automatic rich at 14,250 ft., is 323 mph at 2400 rpm at 1440 bhp per engine.
Speed, wide open throttle with mixture controls set for maximum power at 14,250 ft., is 326 mph at 2400 rpm at 1480 bhp per engine. The airplane will not meet Air Corps cooling requirements when leaned for maximum power. | |
9. | Cruising data in low blower ratio at 15,000 ft.: |
True Speed MPH | R.P.M. | BHP per Engine | |
293 | 2110 | 1085 | |
266 | 1890 | 860 | |
246 | 1740 | 725 | |
210 | 1600 | 615 |
10. | Climb data, low blower used up to 10,000 ft. with throttles open to 38" Hg. manifold presure or wide when below, high blower usded above 10,000 ft. with throttles open to 40" Hg. manifold pressure or wide open when below: |
Altitude | True Speed MPH | R.P.M. | B.H.P. per Engine | Rate of Climb Ft/Min | Time of Climb Min. | |
S.L. | 152 | 2400 | 1400 | 1700 | 0 | |
5,000 | 164 | 2400 | 1415 | 1720 | 2.9 | |
10,000 | 176 | 2400 | 1340 | 1450 | 5.9 | |
15,000 | 188 | 2400 | 1265 | 1175 | 9.5 | |
20,000 | 198 | 2400 | 1080 | 575 | 16.4 | |
25,000 | 207 | 2400 | - | 100 | 36.0 | |
26,200 | 209 | 2400 | - | 0 | - |
MEMORANDUM REPORT ON
Martin B-26A, A.C. No. 41-7347
Subject: | Comparative Speed Tests |
Section: | Flight Section |
Serial No.: | PHQ-M-19-1421-A |
A. | Purpose | |
1. | To report results of comparative speed tests on the B-26A airplane, A.C. No. 41-7347, conducted in order to determine the difference in speed due to the installation of a leading edge glove on the wing. Airplane equipped with two Pratt and Whitney R-2800-5 engines with torque meters and two four-bladed constant speed Curtiss Electric propellers with cuffs. Gross weight as tested with the standard wing was 31,277 pounds with c.g. location, wheels down, at 17.3 percent m.a.c. Airplane was not weighed with the "glove" installed on the wing but was loaded with the same useful load consisting of three crew members and with the wing tanks and right bomb bay tank filled. |
B. | Test Results | |
1. | Speeds in level flight at 5000 feet with the landing gear up, wing flaps up, cowl flaps and oil cooler flaps closed and carburetor cold. |
r.p.m. | Torque Meter b.h.p. per engine | True Speed with Standard Wing m.p.h. | True Speed with Glove Wing m.p.h. | |
2400 | 1350 | 285 | 285 | |
2300 | 1150 | 268 | 268 | |
2125 | 950 | 246 | 248 | |
1900 | 750 | 215 | 220 | |
1700 | 600 | 176 | 181 |
MEMORANDUM REPORT ON
Medium Bomber B-26C, AC No. 41-34678
Subject: | Exhaust Nozzles |
Section: | Flight |
Serial No.: | FS-M-19-1499-A |
A. | Purpose | |
1. | Report on comparative high speed tests with and without the standard exhaust nozzles. Tests conducted with wheels up, wing flaps neutral, cowl and oil cooler flaps closed, mixture auto-rich, carburetor cold. Gross weight unknown; airplane flown in the "as is" condition with full fuel load in wing tanks. |
B. | Test Results | |
1. | Both tests were made with exhaust stack shrouds removed, throttles wide open in low blower ratio at 10,000 feet pressure altitude. |
True Speed MPH | RPM | Avg. b.h.p. per engine | Density Altitude | ||
With nozzles | 289 | 2400 | 1435 | 11,680 | |
Without nozzles | 284 | 2400 | 1435 | 11,500 |
MEMORANDUM REPORT ON
Medium Bomber B-26C, A.C. No. 41-34678
Subject: | Airplane Performance |
Section: | Flight |
Serial No.: | FS-M-19-1500-A |
A. | Purpose | |
1. | Report on performance tests on B-26C. Airplane equipped with two R-2800-43 engines and four-bladed constant speed, full feathering propellers, blade design No. C3821306, normal blade angle range 14.7° to 44.7° at 42 inch radius. All tests conducted with wheels up, wing flaps neutral, carburetor cold, mixture controls auto-rich, cowl and oil cooler flaps in closed position in level flight and wide open in climb, exhaust stack shrouds and exhaust nozzles removed, radio antenae and all guns in place. b.h.p. figures were obtained from power curves No. T-775, revised April 20, 1942. |
B. | Test Results | |
5. | Level flights were made at a pressure altitude of 16,000 feet at wide open throttles in high blower ratio to determine the RPM which would give maximum airspeed. Gross weight at end of test was 29,820 pounds, density altitude 17,400 feet. |
True Speed MPH | RPM | Avg. b.h.p. per engine | |
290 | 2305 | 1300 | |
295.5 | 2415 | 1378 | |
299 | 2510 | 1435 | |
300 | 2610 | 1482 | |
298 | 2710 | 1518 |
MEMORANDUM REPORT ON
B-26, AAF No. 41-17545
Subject: | Flame Damping Exhaust Stacks |
Section: | Flight |
Serial No.: | FS-M-19-1515-A |
A. | Purpose | |
1. | Report flight tests of B-26 airplane, AAF No. 41-17545, equipped with General Aircraft flame damping exhaust stacks and with standard exhaust system. Pratt and Whitney R-2800-5 engines, horsepowers computed from engine curve for R-2800-5 engine, dated August 6, 1940. |
B. | Factual Data | |
1. | High speed, low blower. |
Condition | Altitude Feet | b.h.p. per Engine | RPM | True Airspeed MPH | |
Standard Exhaust Stacks | 8060 | 1500 | 2385 | 294 | |
General Aircraft Flame Damping Exhaust Stacks | 8060 | 1500 | 2385 | 278.5 |
MEMORANDUM REPORT ON
Martin B-26, A.C. No. 40-1385
Subject: | Flight Tests |
Section: | Flight |
Serial No.: | FS-M-19-1528-A |
A. | Purpose | |
1. | To report flight test data obtained in accordance with instructions of the Aircraft Laboratory, on the B-26 airplane, A.C. No. 40-1385, in order to determine the effect of various modifications on this airplane. Airplane equipped with two R-2800-5 engines and four-bladed, constant speed propellers. Left engine equipped with a torque meter. All tests with carburetor cold and two .50 caliber guns in the upper turret. |
MEMORANDUM REPORT ON
Medium Bomber, B-26B, A.C. No. 41-17756
Subject: | Speed Tests |
Section: | Flight |
Serial No.: | FS-M-19-1530-A |
A. | Purpose | |
1. | Report on results of power calibration on B-26B airplane, A.C. No. 41-17756. Airplane equipped with two R-2800-43 engines and four-bladed Curtiss Electric constant speed propellers. Tests conducted in low blower ratio with carburetor cold, cowl flaps closed, oil cooler flaps in the flush positions, mixture auto-rich, wheels up and wing flaps neutral. Airplane not equipped with torque meters, horsepower figures obtained from power charts. |
B. | Test Results | |
1. | Level flight speeds at 4850 feet density altitude. Take-off weight 31,004 pounds, c. g. location, wheels up, 16.9 percent m.a.c. |
True Speed MPH | RPM | Chart b.h.p. per Engine | Gross Weight Pounds | |
281 | 2400 | 1400 | 29,850 | |
250 | 2200 | 1030 | 29,700 | |
208 | 2200 | 740 | 29,600 | |
170 | 2200 | 590 | 29,550 | |
138 | 2200 | 240 | 29,450 |
MEMORANDUM REPORT ON
B-26B-10, Airplane, AAF No. 41-18199
Subject: | Comparative Propeller Performance Tests |
Section: | Flight |
Serial No.: | Eng-47-1675-A |
A. | Purpose | ||
1. | To report results of comparative performance tests run on the B-26B-10 airplane, AAF No. 41-18199, at Wright Field using the following propellers, each assembled in Curtiss controlling hubs, design No. C 543S: | ||
(a) | Curtiss Propeller Division, four bladed, constant speed, full feathering propellers, blade design No. 814-303-18, normal blade angle range 18.0 degrees to 48.0 degrees at 54 inch radius. | ||
(b) | American Propeller Corporation, four bladed, constant speed, full feathering propellers, blade design No. C3821306, normal blade angle range 18.6 degrees to 42.9 degrees at 54 inch radius. |
B. | Factual Data | |
2. | High speeds at 5000 feet at military power in low blower at a gross weight of 31,000 pounds; 2700 r.p.m. and wide open throttles; mixture automatic rich. |
True Speed, MPH | |||||
Manifold Pressure "Hg. | BHP per engine from Power Chart | Curtiss Prop. Blade Design No. 814-3C3-18 | American Prop. Blade Design No. C32821306 | Cowl Flap Position | Oil Cooler Shutter Position |
47.5 | 1880 | 277.5 | 272.5 | Half Open | Wide Open |
Level Speeds |
PERFORMANCE FLIGHT TESTS OF THE
B-26F-1-MA AIRPLANE, AAF No. 42-96231
II | Summary |
The controllability of the airplane was good throughout the normal speed range. The trim tabs were ample to correct for all changes in trim and balance.
The airplane had excellent taxiing and ground handling characteristics.
Power off stalling speed was approximately 110 MPH indicated airspeed with the landing gear and flaps down.
The airplane had no single engine ceiling at normal rated power for gross loads over 31,000 pounds.
Excellent visability was afforded for approach and landing and the landing speed was lower than on previous B-26 models although the flair did not appear to be as good.
Emergency escape for the bombardier would be difficult but was satisfactory for the rest of the crew members.
The principal airplane performance corrected to a standard weight at altitude (take-off gross weight, 35,170 pounds less the weight of fuel used in tak-off and climb to the altitudes was as follows: |
High Speed at Sea Level (military power) | 283 MPH |
High Speed in low blower at 3000 feet (critical altitude for military power) | 287.5 MPH |
Rate of Climb at Sea Level (normal rated power) | 790 ft/min. |
Service Ceiling (two engines) at normal rated power | 19,800 ft. |
Take-off over 50 ft. obtacle at 35,100 pounds using 1/2 flaps (20°) | 2310 ft. |
Speed vs. Altitude |
Climb vs. Altitude |
MEMORANDUM REPORT ON
B-26F-1-MA, AAF No. 42-96231
Subject: | Comparative propeller tests on the B-26F Airplane, AAF No. 42-96231 |
Section: | Flight |
Serial No.: | TSCEP5E-1829 |
A. | Purpose | ||
1. | To report results of comparative performance tests run on the B-26F-1-MA airplane, AAF. 42.96231, at Wright Field, using the following propellers, each assembled in Curtiss controllable hubs: | ||
(a) | American Propeller Corporation, four bladed, constant speed, full feathering propellers, blade design No. C-3821306, normal blade angle range 16.0 degrees to 46.0 degrees at 54 inch radius. | ||
(b) | Curtiss Propeller Division, four bladed, constant speed, full feathering propellers, blade design No. 814-3C3-18, normal blade angle range 17.0 degrees to 48.0 degrees at 54 inch radius. |
B. | Factual Data | |
3. | Power calibration at 5,600 feet (Fig. 2) with American propeller blades, design No. C-3821306. Configuration: wheels retracted, wing flaps neutral, cowl flaps flush, oil cooler flaps closed, low blower. |
Average RPM | Mixture | Test Torque BHP | True Speed | Instant Gross Weight |
2670 | Rich | 1750 | 285 | 32,670 |
2390 | Rich | 1520 | 274 | 32,300 |
2200 | Rich | 1405 | 271 | 32,150 |
2100 | Rich | 1340 | 264 | 31,655 |
2100 | Rich | 1163 | 248 | 31,535 |
2100 | Lean | 995 | 228.5 | 31,455 |
1900 | Lean | 820 | 207 | 31,255 |
1800 | Lean | 752 | 196 | 31,175 |
1700 | Lean | 660 | 175.5 | 31,120 |
1700 | Lean | 590 | 149 | 31,070 |
4. | Power calibration at 5,600 feet with Curtiss propeller blade, design No. 814-303-18. Configuration: Same as paragraph 3. |
Average RPM | Mixture | Test Torque BHP | True Speed | Instant Gross Weight |
2670 | Rich | 1745 | 288.5 | 32,630 |
2400 | Rich | 1550 | 280 | 32,380 |
2195 | Rich | 1415 | 273 | 32,250 |
2100 | Rich | 1340 | 268.1 | 32,010 |
2100 | Rich | 1198 | 254.7 | 31,880 |
2095 | Lean | 1022 | 234.5 | 31,770 |
1900 | Lean | 839 | 210.6 | 31,695 |
1803 | Lean | 775 | 200.3 | 31,625 |
1700 | Lean | 670 | 177 | 31,530 |
1710 | Lean | 618 | 164 | 31,490 |
Power Required at 5600 ft. |
Memorandum Report on B-26 No. 40-1384, Comparative Performance Tests |
Operation and Flight Instructions, B-26, B-26A, and B-26B |
Marauder II Data Sheet |
Marauder Mk. III Data Sheet |