When Clampett was promoted to director in 1937, Jones was assigned to his unit ; the Clampett unit was briefly assigned to work with Jones ' old employer, Ub Iwerks, when Iwerks subcontracted four cartoons to Schlesinger in 1937.

However, following a rough start, Disney left temporarily to earn money at the Kansas City Film Ad Company, and was soon joined by Iwerks who was not able to run their business alone.

Presented as " Newman Laugh-O-Grams ", Disney's cartoons became widely popular in the Kansas City area and through their success, he was able to acquire his own studio, also called Laugh-O-Gram, for which he hired a vast number of additional animators, including Fred Harman's brother Hugh Harman, Rudolf Ising, and his close friend Ubbe Iwerks.

The new series, Oswald the Lucky Rabbit, was an almost instant success, and the character, Oswald — drawn and created by Iwerks — became a popular figure.

Disney went to New York in February 1928 to negotiate a higher fee per short and was shocked when Mintz told him that not only did he want to reduce the fee he paid Disney per short but also that he had most of his main animators, including Harman, Ising, Maxwell, and Freleng — but not Iwerks, who refused to leave Disney — under contract and would start his own studio if Disney did not accept the reduced production budgets.

The first, The Skeleton Dance was entirely drawn and animated by Iwerks, who was also responsible for drawing the majority of cartoons released by Disney in 1928 and 1929.

(; born Ubbe Eert Iwerks, March 24, 1901 – July 7, 1971 ) was a two-time Academy Award winning American animator, cartoonist, character designer, inventor, and special effects technician, who co-created Mickey Mouse with Walt Disney.

Iwerks was considered by many to be Walt Disney's oldest friend, and spent most of his career with Disney.

The first Oswald the Lucky Rabbit was animated entirely by Ub Iwerks.

Financial backers led by Pat Powers suspected that Iwerks was responsible for much of Disney's early success.

Despite a contract with MGM to distribute his cartoons, and the introduction of a new character named “ Flip the Frog ”, and later “ Willie Whopper ”, the Iwerks Studio was never a major commercial success and failed to rival either Disney or Fleischer Studios.

Iwerks directed the first two shorts, while former Schlesinger animator Robert Clampett was promoted to director and helmed the other two shorts before he and his unit returned to the main Schlesinger lot.

Iwerks ' most famous work outside creating and animating Mickey Mouse was Flip the Frog from his own studio.

Iwerks was known for his fast work at drawing and animation and his wacky sense of humor.

A documentary film, The Hand Behind the Mouse: The Ub Iwerks Story was released in 1999, followed by a book written by Leslie Iwerks and John Kenworthy in 2001.

While working for the Kansas City Film Ad Company, Disney decided to take up work in animation, and Iwerks soon joined him.

However, as Iwerks began to draw more and more cartoons on a daily basis, he soon found himself unable to cope under Disney's harsh command ; Iwerks also felt he wasn't getting the credit he deserved for drawing all of Walt's successful cartoons.

However, while animation for a time suffered at Disney from Iwerks ' departure, it soon rebounded as Disney brought in talented new young animators.

In 1936 backers withdrew financial support from the Iwerks Studio, and it folded soon after.

Mary and Lee Blair both soon began to work in the animation industry, joining the Ub Iwerks studio.

* 1930 – The first color sound cartoon, called Fiddlesticks, is made by Ub Iwerks.

* 1928 – Release of the animated short Steamboat Willie, the first fully synchronized sound cartoon, directed by Walt Disney and Ub Iwerks, featuring the third appearances of cartoon characters Mickey Mouse and Minnie Mouse.

Ub Iwerks reworked the sketches made by Disney to make the character easier to animate although Mickey's voice and personality were provided by Disney himself until 1947.

The initial films were animated by Iwerks with his name prominently featured on the title cards.

* Summertime, a 1934 cartoon by Ub Iwerks, featured in a 1986 episode of Pee-wee's Playhouse

A female cow and male horse were created at this time by Iwerks, but were also rejected.

The first few Mickey Mouse and Silly Symphonies cartoons were animated almost entirely by Iwerks.

( The cartoons created by Iwerks ' own studio remained largely unseen for many decades, but have been released to DVD by several companies.

The documentary, created by Iwerks ' granddaughter Leslie Iwerks, was released as part of The Walt Disney Treasures, Wave VII series ( disc two of The Adventures of Oswald the Lucky Rabbit collection ).

Eventually, Iwerks and Disney had a falling out ; their friendship and working partnership were severed when Iwerks accepted a contract with Disney competitor Pat Powers to leave Disney and start an animation studio under his own name.

However Ub Iwerks left Disney with Powers to form his own cartoon studio since he felt that he was the master behind Mickey Mouse and Disney was getting all the credit.

However, Iwerks left the Disney studio in 1930 to form his own company, which was financially backed by Celebrity Pictures owner Pat Powers.

Iwerks would produce three cartoon series during the 1930s: Flip the Frog and Willie Whopper for Metro-Goldwyn-Mayer, and the ComiColor Cartoons for Pat Powers ' Celebrity Productions.

However, by 1936, the Iwerks Studio began to experience financial setbacks and closed after Pat Powers withdrew financial aid to the studio.

The series was the last produced by the studio ; after losing distributor Metro-Goldwyn-Mayer in 1934, the Iwerks studio's senior company Celebrity Pictures ( run by Pat Powers ) had to distribute the films itself.

Powers responded by signing Disney's head animator Ub Iwerks to an exclusive deal to create his own animation studio.

The Whopper series was the second from the Iwerks studio to be produced by Pat Powers and distributed through Metro-Goldwyn-Mayer.

One scene even involves a plane crashing into a " Fireworks " stand which, afterwards is reduced in spelling to " I works " ( the pronunciation of Iwerks ' last name ).

At Pesmen-Rubin he met cartoonist Ubbe Iwerks and when their time at the studio expired, they decided to start their own commercial company together.

After departing the Disney studio, Ub Iwerks created a Horace-like character, the mule Orace, for his own studio.

The short reflects Iwerks ' own fascination with aviation.