Jim Younkin

Jim Younkin is known by many within EAA ( Experimental Aircraft Association) for his creation of the air racing replicas, the Travelair Mystery Ship, and Mr. Mulligan, as well as the super Stearman "Goliath", the Mystery Pacer, and more recently the Mullicoupes. He is also known for his G Model Staggerwing production line which saw three D models converted to G Models and then upgraded with a number of engineering improvements. Finally, he is also known by some for his activity in the art of forming compound aluminum aircraft parts. All these activities were accomplished in his retirement years. Prior to these, his professional career as an electronic engineer was in the field of designing gyro instruments and autopilots for general aviation.

In the late 1950's he developed the first miniaturized solid-state gyro slaving system which he sold to AIM (Aviation Instrument Mfg Co.), the first company to design three-inch gyros to replace WWII-surplus gyros then being installed in new general aviation aircraft. He also became vice president of engineering for AIM where he did extensive design work on the gyros and electronic autopilot pick-offs.

From AIM, Mr. Younkin went to Mitchell Industries where he got paid for what he would have chosen as a hobby, designing autopilots and related instrumentation. One of his early contributions to the then-existing Mitchell autopilot line was to incorporate the Mitchell gyro sensors into the new three-inch gyros being produced by AIM. In so doing he invented the low-friction (so as not to spill the gyro during set) heading selector (bug) into the three-inch vertical card DG. This basic design concept is used today in all autopilot directional gyros.

Mr. Younkin's primary accomplishment at Mitchell was autopilot design. It has been almost 35 years since the Century III was designed, but it is still widely used and known today. He was the sole designer of the Century III. Even today the dynamic performance of this autopilot is better than most being produced, and is exceeded only slightly by those having velocity feedback of the servo actuator drive motor responding to electronic rate signals derived from position sensors within the artificial horizon. The Century III was the first attitude position autopilot to fly without feedback sensors on the servos. This provided much simplification of design, hardware count, and ease of installation. This breakthrough is copied today in many autopilots.

Mr. Younkin also developed the Century I and Century IV, and contributed to the design of the Century Forty-one, which evolved into the present-day Century 2000. The Century I is the first all-electric so-called "rate-based" autopilot. This was an entry-level product intended to fill a void at the low end of the product line. Another product, the NSD-360 horizontal situation indicator (HSI) is Mr. Younkin's design. This unit is probably in greater use today than any other HSI, and it is still being produced. As could be expected, Mr. Younkin holds numerous autopilot patents.