Question: What type of engine was used in the planes used in the raid led by Colonel James “Jimmy” Doolittle?
Context: James Harold Doolittle (December 14, 1896 – September 27, 1993) was an American aviation pioneer.  A Reserve officer in the United States Army Air Corps, Doolittle was recalled to active duty during World War II.  He was awarded the Medal of Honor for personal valor and leadership as commander of the Doolittle Raid, a bold long-range retaliatory air raid on the Japanese main islands, on 18 April 1942, four months after the Attack on Pearl Harbor.  He was eventually promoted to lieutenant general and commanded the Twelfth Air Force over North Africa, the Fifteenth Air Force over the Mediterranean, and the Eighth Air Force over Europe. The Kawasaki Ki-61 "Hien" (飛燕, "flying swallow") is a Japanese World War II fighter aircraft used by the Imperial Japanese Army Air Service.  The Japanese Army designation was "Army Type 3 Fighter" (三式戦闘機).  Allied pilots initially believed Ki-61s were Messerschmitt Bf 109s and later an Italian aircraft, which led to the Allied reporting name of "Tony", assigned by the United States War Department.  It was the only mass-produced Japanese fighter of the war to use a liquid-cooled inline V engine.  Over 3,000 Ki-61s were produced.  Initial prototypes saw action over Yokohama during the Doolittle Raid on 18 April 1942, and continued to fly combat missions throughout the war. The Airspeed AS.57 Ambassador was a British twin piston-engined airliner that first flew on 10 July 1947 and served in small numbers through the 1950s and 1960s.  The planes are sometimes referred to as "Elizabethans", as they were originally ordered and popularized by British European Airways as the planes used for their "Elizabethan Class" passenger service. Operation Rhino was a raid led by the United States Army's 75th Ranger Regiment (3rd Ranger Battalion), who were led by Colonel Joseph Votel, and the 101st Airborne Division on several Taliban targets in and around Kandahar, Afghanistan during the invasion of Afghanistan at the start of the War in Afghanistan (2001–2014). Gung Ho!  (full title: Gung Ho! : The Story of Carlson's Makin Island Raiders) is a 1943 American war film directed by Ray Enright and starring Randolph Scott.  The story is based on the real-life World War II Makin Island raid led by Lieutenant Colonel Evans Carlson's 2nd Marine Raider Battalion. The Doolittle Raid, also known as the Tokyo Raid, on Saturday, April 18, 1942, was an air raid by the United States on the Japanese capital Tokyo and other places on the island of Honshu during World War II, the first air operation to strike the Japanese Home Islands.  It demonstrated that Japan itself was vulnerable to American air attack, served as retaliation for the Japanese attack on Pearl Harbor, and provided an important boost to American morale.  The raid was planned and led by Lieutenant Colonel James "Jimmy" Doolittle of the United States Army Air Forces. The George's Schoolhouse Raid was a Confederate partisan raid led by local guerrilla John Mobberly on the Union garrison at Lovettsville in Loudoun County, Virginia on January 17, 1865, during the American Civil War.  The raid was tactically inconclusive.  After surprising the sleeping garrison, the Confederates were driven away by superior force, taking with them only a few horses and prisoners.  The raid is notable for being the last partisan action in Loudoun County involving Elijah V. White's 35th Battalion of Virginia Cavalry. Ku Klux Klan activities in Inglewood, California, were highlighted by the 1922 arrest and trial of 36 men, most of them masked, for a night-time raid on a suspected bootlegger and his family.  The raid led to the shooting death of one of the culprits, an Inglewood police officer.  A jury returned a "not guilty" verdict for all defendants who completed the trial.  It was this scandal, according to the "Los Angeles Times," that eventually led to the outlawing of the Klan in California.  The Klan had a chapter in Inglewood as late as October 1931. Carleton's Raid was a British raid led by Major Christopher Carleton during the American War of Independence, conducted in fall 1778 from the Province of Quebec against targets in upstate New York and the Vermont Republic. The Plum River raid was a bloodless skirmish that occurred at present-day Savanna, Illinois, on May 21, 1832, as part of the Black Hawk War.  Most of the settlement's inhabitants, except for a few defenders, had fled for Galena, Illinois, before the raid happened.  A small band of Native Americans, either Sauk or Fox, attacked the settlement while only three of the six defenders were present.  The men who were present fell back to the blockhouse and a firefight ensued for about one hour, after which the attackers withdrew.  No one was killed or injured during the attack, but in its aftermath Colonel James M. Strode dispatched a detachment of militia to Savanna.  They returned to Galena without incident and the settlement at Savanna was temporarily abandoned.
Answer: liquid-cooled inline V engine