B-24 Liberator

History:
Consolidated Aircraft hit a huge home run with the Model 32 Liberator, an aircraft which General "Hap" Arnold hoped would "fly the skin off" any of its rivals.  It was an extremely advanced aircraft for its time, and utilized a variety of systems that required a great deal of training and teamwork from the crew.  The most unusual feature of this airplane was its high-aspect ratio Davis wing, which was adopted by Consolidated without that firm actually having any proof from the designer that the wing was any more efficient than the NACA designs used on the B-17 and most other aircraft of the time.  Testing of this wing seemed to indicate a slight advantage, however, and it was adopted.  In the end, the Liberator proved difficult to fly, only marginally stable, and was often flown at maximum overload weights which greatly exacerbated these traits.  The Davis wing itself has since been shown to be no better and perhaps worse than other alternatives available at the time, but the science of designing and testing airfoils was in its infancy at the time and the pressures of a war on surely contributed to the decision to use it.

The B-24 was not a forgiving aircraft, and was demanding to fly.  It was important to keep the aircraft properly trimmed or it would wander all over the sky.  The wing loading at maximum weight was quite high and it was sensitive to being flown at the proper airspeeds and in the proper state of trim.  It was never known as a "hands-off" airplane as was the B-17.  In the end, though, the Liberator proved to be very effective at getting bombs on the target despite the demands on her crew, and 18,188 of the type, in all variants, were built.  This compares with 12,731 B-17 aircraft and 7,366 Lancasters.

At the time of this writing, only a single B-24J remains flyable.  It belongs to the Collings Foundation, in Stowe, Massachusetts, and continues to tour the United States ten months out of the year as a living museum and testament to the dedication of the men who flew her.  We flew in this aircraft on two occasions while researching this project and came away with a deep respect for those who operated her in combat.

 

Pilot Comments:

"You could always tell a Liberator pilot by the bulging biceps muscle in his left arm, from hauling on that yoke for 14 hours at a stretch."

"Where the B-17 was an airplane, the B-24 was a truck."

"The airplane has inherent directional stability which may be maintained for long periods of time by slight adjustments in trim.  However, the controls are normally heavy, as they should be in a heavy airplane, and the pilot who fails to maintain proper trim is in for an exhausting workout." (From the B-24 Training Manual)

 

 

 

 

 
Cockpit Layout B-24J

 

 

 

 
Cockpit Layout B-24D

The B24-D cockpit layout is quite similar to the B24-J except for a few differences notes below:

 

 

Panels

 

Electrical Panel

 

 

Sperry Autopilot

 

See the Sperry Autopilot section at the end of this manual for more information.

 

 
Technical Specifications

 

ABBREVIATED CHECKLIST

ENGINE START


TAKEOFF

Apply power smoothly and gradually, walking the throttles forward evenly until reaching full takeoff power in the first 1/3 of the runway.  The aircraft will have a moderate tendency to pull to the left; use right rudder or differential throttle to correct.  Good rudder control is achieved by 80 mph IAS.  At 90 mph IAS, pull back on the yoke to lighten the nosewheel and assist in raising the nose.  Hold the nose up and allow the aircraft to fly itself off the runway at about 120-130 mph, depending on gross weight.  Retract gear as soon as a positive rate of climb is established. After reaching 140 mph IAS reduce power to rated power (46" Hg and 2550 rpm).  Retract flaps before reaching 150 mph IAS.  Hold the aircraft in a very shallow climb until an indicated airspeed of 155 mph is achieved.

Takeoff Distance (to clear 50' obstacle)

Weight, pounds

Distance, feet

60,000

4,250

 


CLIMBING

Climb at an indicated airspeed of 155 mph with a power setting of 46" of manifold pressure and 2550 rpm.  For lower weights use 41" and 2550 RPM.  Cowl flaps are normally set to about 1/3 open or less for climbing.  Maximum cylinder head temperature is 260 degrees Celsius.  This aircraft was equipped with an automatic mixture control.  Therefore, no mixture adjustment is necessary.

CRUISING

The B-24 must cruise "on the step" in order to get the maximum possible range.  To get "on the step" climb to at least 500 feet above your desired cruising altitude and allow the aircraft to accelerate to cruising speed while descending to the cruising altitude.  Normal cruising speeds for the B-24 are 140-160 mph IAS depending on the aircraft weight and altitude.  The aircraft will cruise in a slightly nose-up attitude at heavier weights and higher altitudes.  The maximum cylinder head temperature is 232 degrees.

The B-24 normally cruises at a manifold pressure of about 30" and an engine RPM of 2000 or less.  Use the following chart to determine the correct power condition and speed for cruise at a given aircraft weight.  This aircraft was equipped with an automatic mixture control.  Therefore, no mixture adjustment is necessary.


Cruise at 25,000 Feet Density Altitude
(Chart is for B-24J; figures for B-24D are approximately 1-2 percent better due to slightly lower parasite drag)

Weight

IAS, mph

TAS, mph

Boost

RPM

BHP

GPH

MPG

60,000

155

229

32

2200

754

209

1.09

55,000

155

229

31.5

2200

735

204

1.13

50,000

155

229

31

2100

692

192

1.20

45,000

155

229

31

2050

675

188

1.23

Cruise at 5,000 Feet Density Altitude

Weight

IAS, mph

TAS, mph

Boost

RPM

BHP

GPH

MPG

60,000

155

166

31

1750

540

150

1.10

55,000

155

166

30.5

1700

517

144

1.15

50,000

155

166

30

1700

500

140

1.18

45,000

155

166

30

1690

497

138

1.21

 

 


LANDING

Calculate the power-off stalling speed based on the aircraft weight.  Set engines to 2400 RPM and adjust power as required to achieve an airspeed of 160 mph IAS.  Enter the pattern at either the crosswind or downwind leg at an indicated airspeed of 160 mph and 1,500 feet AGL.  If possible, enter the pattern on the crosswind leg and fly 2-3 miles out from the runway.  This will provide ample room to maneuver the aircraft.  Fly the downwind leg at 150 mph IAS, lowering flaps to 10 degrees abeam the runway threshold.  Turn base 2-3 miles beyond the runway threshold at 145 mph IAS.  Allow the aircraft to descend to 1,000 feet AGL on the base leg.  Lower the flaps to 20 degrees just before turning to your final approach and reduce airspeed to 135 mph IAS.  At this point, move the propellers to the high speed position.  The power setting should be about 25" of Hg at this point.  Do not lower the flaps fully until the runway is made.  Maintain a speed of about 125-130 mph IAS for the final approach.  Pick a point about ten feet in front of the runway threshold and line this up with the end of the nose to set the correct glidepath.  A normal final approach is made with 15-18" of power at 125-130 mph with a descent rate of 500 fpm.  Begin the flare about 150 feet above the runway, reducing power and landing smoothly at an airspeed of about 105-110 mph.  Hold the nose off as long as possible.


 

Special Features of This Aircraft

Clicking on the compass icon will bring up the co-pilot's panel.  Use the "reset eyepoint" key to return to the normal view, or flick the hat switch, cycle the views, or switch to any other view.

More Information

The above procedures are abbreviated but were taken directly from the official manual issued to pilots for training purposes.  This manual is now widely available.  For the most realistic possible flying experience, obtain a copy of this manual and use it to fly your Wings of Power aircraft.  You will find that you can use the manual to fly this virtual aircraft and it will perform exactly as specified in the original training manual.


Wings of Power Certified Specifications (B24D):

Wings of Power Certified Specifications (B24J):

 

Historical Documents