For her around-the-world flight, the airplane that Amelia Earhart chose was a Lockheed Electra 10E, manufactured by the Lockheed Aircraft Company, Burbank, California. The Electra Model 10 was an all-metal, twin-engine, low-wing monoplane with retractable landing gear, designed as a small, medium-range airliner. In the standard configuration it carried a crew of 2 and up to 10 passengers. The Model 10 was produced in five variants with a total of 149 airplanes built between August 1934 and July 1941. Lockheed built fifteen Model 10Es. Earhart’s was serial number 1055.
$80,000 to buy the Electra was provided by the Purdue Research Foundation from donations made by several individuals. George Palmer Putnam, Amelia’s husband, made the arrangements to order the airplane and in March 1936 gave Lockheed the authorization to proceed, with delivery requested in June. The modifications included four auxiliary fuel tanks in the passenger compartment, a navigator’s station to the rear of that, elimination of passenger windows, installation of a Sperry autopilot and various radio and navigation equipment and additional batteries. The Electra was not ready until mid-July.
Amelia Earhart test flew the new airplane at Burbank on 21 July with Lockheed test pilot Elmer C. McLeod. She accepted the Electra on her 39th birthday, 24 July 1936. It received civil certification NR16020. (The letter “R” indicates that because of modifications from the standard configuration, the airplane was restricted to carrying only members of the flight crew, although Earhart and her advisor, Paul Mantz, frequently violated this restriction.)
The Electra 10E was 38 feet, 7 inches (11.760 meters) long with a wingspan of 55 feet (16.764 meters) and overall height of 10 feet, 1 inch (3.074 meters). The standard Model 10 had an empty weight of 6,454 pounds (2,927.5 kilograms) and a gross weight of 10,500 pounds (4,762.7 kilograms). NR16020 had an empty weight of 7,265 pounds (3295.4 kilograms). Lockheed’s performance data was calculated using 16,500 pounds (7,484.3 kilograms) as the Maximum Takeoff Weight.
NR16020 had a total fuel capacity of 1,151 gallons (4,357 liters) in ten tanks in the wings and fuselage. 80 gallons (302.8 liters) of lubricating oil for the engines was carried in four tanks.
Earhart’s Electra 10E Special was powered by two air-cooled, supercharged, 1,343.804-cubic-inch-displacement (22.021 liter) Pratt & Whitney Wasp S3H1 nine-cylinder radial engines, with a compression ratio of 6:1. These engines used a single-stage centrifugal supercharger and were rated at 550 horsepower at 2,200 r.p.m. at 5,000 feet (1,524 meters) and 600 horsepower at 2,250 r.p.m. for take off. The direct-drive engines turned 9 foot, 7/8-inch (3.010 meters) diameter, two-bladed, Hamilton Standard variable-pitch, constant-speed propellers. The Wasp S3H1 is 4 feet, 3.60 inches (1.311 meters) in diameter and 3 feet, 7.01 inches (1.093 meters) long. It weighed 865 pounds (392 kilograms).
A detailed engineering report was prepared by a young Lockheed engineer named Clarence L. (“Kelly”) Johnson to provide data for the best takeoff, climb and cruise performance with the very heavily loaded airplane. The maximum speed for the Model 10E Special at Sea Level and maximum takeoff weight was 177 miles per hour (284.9 kilometers per hour), a reduction of 25 miles per hour (40.2 kilometers per hour) over the standard airplane. The maximum range was calculated to be 4,500 miles (7,242.1 kilometers) using 1,200 gallons (4,542.5 liters) of fuel.
Johnson would later design many of Lockheed’s most famous aircraft, such as the SR-71A Blackbird Mach 3+ strategic reconnaissance airplane. As a student at the University of Michigan, he worked on the wind tunnel testing of the Lockheed Electra Model 10 and made recommendations that were incorporated into the production airplane.
The Electra was heavily damaged when it crashed on takeoff at Luke Field (NAS Ford Island), Honolulu, Hawaii, on the morning of 20 March 1937. It was shipped back to Lockheed for extensive repairs. An investigating board of U.S. Army officers did not report a specific cause for the accident, but there was no evidence of a “blown tire” as had been reported in the newspapers. The repairs were completed by Lockheed and the aircraft certified as airworthy by a Bureau of Commerce inspector, 19 May 1937. The airplane had flown 181 hours, 17 minutes since it was built.
Earhart’s Electra was equipped with a Western Electric Model 13C radio transmitter and Model 20B receiver for radio communication. It used a Sperry GyroPilot gyroscopic automatic pilot.
© 2018, Bryan R. Swopes
This is an excellent and informative summary. Thank you.
Thank you, Donald.
Awesome to read about this famous airplane, I hope one day it will be discovered.
Re the photo with the engine and prop: She sure had long arms 🙂
Sort of glad to hear the tire problem at takeoff, I often wondered why she lost control at takeoff in Hawaii being an experienced pilot. I have been watching videos about the trip lately and i can figure she landed on Nicaromoho ? sp and apparently lost one of the main gears in a collapse on the coral. This landing apparently seriously injured Fred and minor injuries to her. The three days when she did broadcast, after the landing were picked up by a gal in Florida. That short wave girl in Florida was aware of the injuries. The navy did do a flyover and circled around this island but i dont know when they did it accordance with the date of the landing. By then the aircraft remains except for a single landing gear stuck in the coral were wash out to sea. Per a picture which could show the tire, gear. She may have been unable to alert the Navy flyover or was injured too badly to reply with any form of communicating.
I dont feed that pilots make very good visual search agents. Searching in a low wing aircraft is not advisable. Its too bad a PBY wasn’t available i believe they would have found her.
There was no “tire problem” on the 20 March 1937 takeoff attempt. Earhart caused an uncontrolled ground loop which resulted in the Electra’s right side landing gear collapsing. The Army found nothing mechanical which would have caused the ground loop. This was the first time that Earhart had taken off in the Electra without another pilot in the cockpit. Her advisor, Paul Mantz, had criticized her use of throttles for directional control during previous takeoffs.
TDiA recommends “Finding Amelia: The True Story of the Earhart Disappearance,” by Ric Gillespie. (Naval Institute Press, 2006). The book is thoroughly documented, and at least the first edition comes with a CD with includes much of that documentation, including the actual U.S. Army investigation report of the takeoff crash.
Bryan. With her gas tanks empty (1200 gallons volume), the plane could have enough floatation not to sink for a while… assuming she did not crashed into the ocean hard. Has anybody considered this option?
Yes, The original search by the Unites States navy was carried out in the open ocean. I highly recommend Finding Amelia: The True Story of the Earhart Disappearance by Rick Gillespie. Published by Naval Institute Press, Annapolis, 2006.
Is her remains has been discovered or not yet
No, nothing has been proven. In 1940, human bones were discovered on Gardner Island (now known as Nikumaroro). Other artifacts were also located. They were sent to Fiji for evaluation and it was determined that the bones were from an adult male. A modern forensic evaluation of the bone’s measurements concluded, however, that Earhart’s bones would have been “more similar to the Nikumaroro bones than 99% of individuals in a large reference sample.”