The Cessna 310 as a U-2 Trainer

The Cessna U-3A "Blue Canoe"

In 1957 the United States Air Force selected the Cessna 310 twin as its new utility transport for light cargo, liaison, and administrative missions to replace the Beech C-45 which was a military adaptation of the stalwart Beech 18 transport. Eighty were ordered and originally designated L-27 (in 1962 the rationalization of military aircraft designations led it to be redesignated the U-3). That first group of 80 aircraft were delivered within the year thanks to Cessna's already high production output to meet the civilian market. Another 80 were ordered later that same year and in 1960 came the final contract for another 35, this time of the swept fin version of the 310. The older version with the straight vertical fin became the L-27A, later U-3A, and that last group of aircraft were designated the L-27B, later the U-3B. The distinctive blue and white colors used by the USAF on the aircraft led to its nickname, "Blue Canoe" and even though the US Army and the US Navy ordered the aircraft and used their own service specific color schemes, personnel still referred to the aircraft as the "Blue Canoe". But one of the most unique uses of the U-3 was also its most little-known and in the smallest of numbers by the military- that of a trainer for the early U-2 program!

At the time, Lockheed U-2 pilot training was the responsibility of the 100th Strategic Reconnaissance Wing at Davis-Monthan AFB in Arizona. The first-generation U-2 spyplanes didn't have a two seat trainer version in use at the time, which made every pilot's first flight in the U-2 a solo flight- and even back then, the U-2 had the unenviable reputation as one of the most difficult aircraft to land properly. The 100th SRW had already been using a souped vehicle, the "Mobile", which back then was a Ford El Camino modified with a big-block engine which would sprint down the runway alongside the landing U-2 to assist the pilot with altitude information as the U-2's long span wings meant that the only way to land was to land in a full-stall. The Mobile called out altitude down in single foot increments until the aircraft was only a foot above the runway at which point speed was bled off to stall the aircraft into a touchdown. Needless to say, it was a completely counter-intuitive way to land an aircraft and was just one of many idiosyncrasies of the "Dragon Lady". But an aircraft was needed that could help train novice U-2 pilots to the point before the Mobile took over assisting with the landing. The 100th SRW evaluated different types of aircraft and quite surprisingly, found the Cessna U-3 ideal for the role. It was inexpensive, available, dual control, and it had a yoke which the U-2 also had as well. With most U-2 pilots coming from the fighter community, many hadn't used a yoke since basic flight training. The instructors at the 100th SRW specifically selected the straight-fin U-3A as the later swept-fin version was more unstable at the low approach speeds needed to train novice Dragon Lady pilots. 

An early generation U-2 from the U-3 chase plane

The U-3 had a turn rate, descent profile and pattern airspeed very close to that of the U-2; given that airspeed management was critical in the U-2 given its very narrow handling envelope, the "Blue Canoe" could be used as both a training aid and chase aircraft for a U-2 on approach. On training missions out of Davis-Monthan AFB, the pair in formation was known as the U-2 and "Me-Too". The U-3 would intercept the approaching U-2 at 15,000 to 18,000 feet at 160-180 KIAS and stay on the spyplane's right wing through the descent and traffic pattern until the landing was handed over to the Mobile. In addition, the sightlines from the student's seat in the U-3 were similar to that of the Dragon Lady and it was used as a pre-solo trainer. In preparing U-2 pilots for their first flight in the spyplane, the U-3 was known as the "Dragon Lady Pattern". The instructor would manage the flaps and throttles on the simulated approach to mimic the flying characteristics of the U-2 while the student in the left seat concentrated on the approach. Because the U-2 was stalled one foot above the runway in order to land, the student was required to level off and float the Cessna U-3 one foot starting over the numbers and to maintain that one foot altitude the entire length of the 12,500 foot runway at Davis-Monthan. If the student completed this exercise several times to the satisfaction of the instructor, the U-3 would then land and taxi to a waiting U-2 where the student would climb in for their first solo flight with the U-3 flying chase. For the first solo flight, the wing pogo gears were locked into place. 

Note the pogo landing gear still in place as seen from the U-3A.

The instructor in the U-3 then took off and waited at 15,000 feet for the student in the U-2. Once they had rendezvoused, the instructor by radio then walked the student through various approach-to-stall exercises as well as manually trimming the aircraft for landing by pumping fuel amongst the wing tanks to even the aircraft out. With a 100+ foot wingspan and a wet wing, it was critical that the fuel be evenly distributed through the wing tanks before landing. If the student had done this satisfactorily, it was time to shoot some approaches in what was called the "Dragon Lady Checkout". With the U-3 flying as "Me-Too", the student completed three traffic patterns with touch and gos with the Mobile participating in the final touch down. Completion of this exercise meant the newly minted U-2 pilot could proceed with advanced training. Only two Cessna U-3As were assigned to the 100th SRW at the time and the pace of training meant that no more aircraft than that were needed and only three instructors were checked out to train and fly chase in the U-3. The U-3As also flew chase in emergency situations to assist pilots in getting the U-2 back to the base and often flew chase for pilots returning from long-duration missions who were at their most vulnerable due to exhaustion. 

Source/Photos: Cessna Warbirds- A Detailed & Personal History of Cessna's Involvement in the Armed Forces by Walt Shiel. Jones Publishing, 1995, p127-132. Additional photos from the USAF Museum.