Special Exhibit:

Annco One

(Click on any of the images on this page to see a larger version)

Whatever plane the President of the United States flies is called Air Force One. Whatever servo the President of Annco flies may similarly be deemed Annco One. This was Fred Wallman’s personal Annco servo he flew in his planes. Fred was the President and founder of Annco Engineering. From 1961 to 1967, Annco grew to become one of America’s leading servo manufacturers. Orders for his smaller, lighter actuators poured in from across the country and around the world. Annco had to move its production three times to increasingly, larger plants. Then proportional systems became sufficiently reliable and inexpensive to put reed systems out of business. Annco’s servo business dwindled, then stopped. In the end, this single servo was all that Fred Wallman had left of his once-sizable servo empire.

Annco One.

In 1960, Fred Wallman had a vision of a smaller, lighter, linear arm servo. In 1960 and 1961 he experimented with various models at his little shop in his garage in Richfield, Minnesota. Gradually, he refined his design and the vision became reality.

100% Advantage
The new servo was only 1” x 1 3/16” x 1 3/16” and weighed just 1.2 ounces. By comparison the industry-standard Bonner Duramite servo was 3 x 1 5/8 x 1 and weighed
2½ ounces. In addition to this, the Annco servos were the first to feature push-pull arms extending from either side of the case. This was widely copied (e.g. Kraft, Controlaire, F&M, Min-X and PCS), which amounted to a tribute to Fred Wallman from his peers. The claimed power was over 3 pounds thrust for the Anncos versus over 4 pounds thrust for the Bonners.

While the Bonners had 25% more power, imagine the appeal of the Anncos to weight sensitive modelers given the Bonners weighed
over 100% more.

Here is a picture of the Annco and Bonner servos together:

Here is the new product announcement and first advertisement for the Annco servo (Sept 61 AM).

Family Business
Fred came up with the name “Annco” to honor his wife Anne. In the beginning, this was a true, home-based business staffed by the Wallman family. The shop consisted of a circa 1898 screw machine (turning aluminum push rods, brass adjustable end screws and gears), a 1943 Logan lathe, a ¼ ton and ½ ton punch press, a shaper, floor and table drill presses, and their pride, a brand new Bridgeport Mill. Fred’s son Michael manned the screw machine, his son Fred III the lathe and his wife Anne and daughter Julia took turns at the various machines and assembly tables. (In 2008 Michael Wallman authenticated Annco One on its back and provided much of the information set forth here). Fred was the inventor, designer, production chief and toolmaker and he conducted his own advertising, marketing, packaging and shipping.

As transistors became commonplace, multi-channel receivers went relayless to eliminate the additional weight, complexity and maintenance of relays. In the February 1962 edition of Flying Models, Annco’s new relayless servo was introduced. Relayless servos required electronic amplifiers and the additional components necessitated enlarging the case to 1 ¾ x 1 ½ x 3/4”, and caused the weight to increase to 1.7 ounces.

This was still considerably smaller than the industry-leading Bonner Transmite relayless servos, and the Bonner actuators still weighed 76% more (at 3 ounces).

Here is the product announcement (Feb/Mar 62’ F.M.):

And here is the first advertisement for the new Annco servos (Feb/Mar 62’ F.M.):

Evolutionary Advances
Notice how Annco had replaced brass and aluminum parts with Nylatron (gears and output arms). Note also that the product announcement credits no less than Phil Kraft as the designer of the 4 transistor amplifier. After awhile Annco substituted 6, and then, 7 transistor amplifiers designed by Don Kam, an electronics “wizard” in Fred Wallman’s local club, Twin Cities RC.

Here are examples of the early Annco amplifier with “Kraft” on the circuit board and the later model with Don Kam’s initials:

Here in comparison, is one of the six-transistor amplifiers designed by Bob Elliot (later of EK Logictrol) for the industry-leading Bonner Transmite servos:

Not long after their relayless servos were rolled out, Annco discontinued the German micro-perm motors and began to make its own. This was either due to difficulty acquiring large numbers of micro-perms as Annco production ramped up, or simply to bring more components in house to better control quality and costs and enhance profitability. Armatures were built from scratch, machining the shafts, stamping the core laminates, fabricating the conmutator and winding each armature on a special machine. A unique circular magnet was employed made of ceramics so it could be ordered to the exact size needed. A special brass eyelet-tube housing was developed for the brushes/contacts so they could be serviced and replaced without having to take the entire motor apart.

Here’s one of these special Annco motors,
in situ, together with, for comparison, one of the orange micro perm predecessors and the much larger motor used in Bonner servos (also made in-house).

Here are specimens of the various generations of Annco relayless servos. The earlier models had metal adjusters on the output arms and deep gold anodizing like the earliest (relay) Anncos:

Here is the presentation Fred Wallman gave at the 1965 DCRC Symposium (first page only), and a picture of him lecturing there: