Federal Signal Twinsonic History Models and Features

History

The Federal Signal Twinsonic light bar was the creation of Federal Signal’s lead design engineer Earl Gosswiller (1912-2009). Earl created the Twinsonic as a fully enclosed rotating beacon light bar that stretched across the roof of patrol cars in 1967. The Twinsonic debuted at the 1968 International Association of Fire Chiefs convention in Louisville, Kentucky. The light bar was an instant success with 400 being built in 1968 and 1969. Federal Signal also introduced the Model TS24 58-watt speaker to be housed inside the stainless steel enclosure.

Model 12 Series A1 & A3: The model 12 series A1 and A3 was a 54-inch full size light bar with (2) tall triple reflection single direction mirrors mounted next to the rotators. The first additions had black anodized aluminum frames and completely round bulb holders.

Model 12X: The next brain storm from Earl was the model 12X which took the (2) tall triple reflection mirrors and cut them horizontally and rotated the top half 180 degrees to face the rear. Now you had just as many flashes to the front as you did the rear.

Model 12F: The next product line was the 12F light bar which originally consisted of (4) PAR 36 (4414) bulbs mounted next to the rotators and these flashed in a wig wag pattern to the front and rear. By 1972 this was replaced by the new style 12F with lower front facing cascade mirrors and a top flasher housing with (2) polycarbonate filters made from cut down Dietz lenses.

Series A1: Featured metal speaker trays and both Series 1 and Series 2 motors. The series 1 motor has rounded sides and a flat top and bottom. This motor is assembled with stronger windings to reduce fatigue over time. The Series 2 motor had similar properties as the heavy duty Series 1 model but the castings were different. The second series had an X in the cast on the rear of the housing.

Model CTS: In 1972 Federal Signal entered into an agreement to build a special service bar to meet California Vehicle Code Section 25252 states that: “Every authorized emergency vehicle shall be equipped with at least one steady burning red warning lamp visible from at least 1,000 feet to the front of the vehicle. This model of light bar was the CTS series. This light bar featured a PAR 46 (GE 4001) steady burn red bulb on the inner driver’s side and a PAR 46 (GE 4478) mounted inner drivers side to the rear. This bulb was normally mounted in front of a cut out in the dome with an amber panel bolted and glued to the rear of the lens.

Small Models: By 1974 they came out with a “small” line of Twinsonic light bars that measured 47-1/4 inches in length. These were available in all the common models.

Economy Line: In 1974 they also came out with their Economy line which removed the stainless steel strips from the bar and replaced the stainless speaker cover with an aluminum one.

A3 Series: In 1974 they introduced the A3 Series line. This line featured natural color aluminum frames. They also switched to plastic speaker trays and the “skinny” bulb holders for the rotators.

In 1976 we see a change to the new series 3 motor. This motor is round in diameter and was not built to meet the same demands of the Series 1 and 2. The Series 3 motors were offered in the Twinsonic rebuild kits.

Medium Line: In 1977 Federal Signal introduced the “medium” line of Twinsonic’s which measured 47-1/2 inches. These light bars were available in all the common Twinsonic models.

Dual Motors: There were a small number of Twinsonic’s built with dual motors, but I don’t have any information for them. Allegedly the fleet manager at a police department was concerned that going from dual beacons with each having their own motor to a bar with only (1) motor would be a downfall for the Twinsonic. Federal Signal designed a dual motor setup for this agency. Others followed suit but the demand was not great. This option was apparently around a $70 option.

Bulbs: The Twinsonic had  30 or 60 Watt bulbs depending on the used color of the bulb. Clear & red are 60 Watt (GE#4464 & GE#4464R) and amber & blue are 30 Watt (GE#4416A & GE#4416B).

Biggest Production Years: The years 1976-1980 saw the biggest production years of the Twinsonic. These bars lost production numbers when the Aerodynic and Jetsonic light bars came into fruition. The last light bar according to Federal Signal was sold to the Pierce manufacturing company in August of 1984. It was sold to a department in South Dakota.

Federal Signal manufactured 30 different variations of the Twinsonic.

Twinsonic 1981 Price List

The Twinsonic light and sound system set the standards for vehicle warning systems! It has two sealed beam rotating end lamps reflecting on inner mirrors, providing brilliant flashes of light warning. Models are available in single direction (front) or dual direction (front and rear). Choice of 12 or 24 volts.