The Comet 7-cylinder radials were a family of air-cooled radial engines, designed and built by the Comet Engine Corporation at Madison, Wisconsin from around 1927.

Design and development

Comet designed the 7-cylinder radial series to take advantage of the boom in private aviation in the late 1920s; intending to replace the large number of relatively unreliable wartime surplus engines that flooded the market in the early 1920s. First produced by the Aircraft Engine Corporation of Oakland, California, new interests acquired the California company and the Comet Engine Corporation was formed under the sponsorship of Air Investors Inc., the Crocker First Company of San Francisco and the Gisholt Machine Company. Production transferred to workshops adjacent to the Gisholt Machine Company in Madison, which acted as production supervisor. Comet 7E (5272720037)

The Comet radial was fairly standard with steel finned cylinders, cast light alloy cylinder heads and two valves per head. The valves are operated by a single rocker arms and push-rods, to the rear of the cylinder, which are in turn operated positively by inner and outer cam tracks operating rollers on the pushrod. Oil pumps and magnetos are driven by the camshaft drives as well as the Heywood air starter and tachometer. The two-piece crankshaft, with counter-weights, is carefully forged from heat-treated chrome-vanadium alloy steel and drilled for lightness and lubricating oil flow. Master and slave connecting rods are forged and machined from the same material as the crank-shaft. The rear of the crankshaft carries an induction rotor to ensure even mixture distribution to the cylinders from the Stromberg carburettor. The two-piece crankcase is split in the plane of the cylinder centres, with the forward half supporting the fwd crank /prop-shaft bearing and the rear half housing the rear bearing, induction rotor, cam drives and accessories.

Variants

''Data from: ;7-RA: From 1928 with Approved Type Certificate No.9, rated initially at at 1,800 rpm. ;7-D: After improvements rated at at 1,800 rpm (maximum continuous) from . ;7-E:From 1929 with Approved Type Certificate No.47, delivering from the same .

Applications

''Data from:'' Aerofiles : Aircraft of North America 1903-2003 *

Adcox Student Prince The Adcox Student Prince was a two-seat open- cockpit biplane designed by Basil Smith and built by the students of the US Adcox Aviation Trade School in 1929. It was based on the one-off Adcox Special, and the first example flew on 17 September. ...

Alexander Eaglerock Bullet C-4 The Bullet Monoplane or Alexander Eaglerock Bullet was a low wing cabin monoplane that was a departure from traditional biplane aircraft of the era. Design and development The Bullet was built at the beginning of the Great Depression. Company ow ...

(7-E option not installed) *

Alexander Eaglerock A-12 Alexander is a male given name. The most prominent bearer of the name is Alexander the Great, the king of the Ancient Greek kingdom of Macedonia who created one of the largest empires in ancient history. Variants listed here are Aleksandar, Al ...

7-RA and some re-engined with 7-E * Bach 3-CT-5 (2x 7-RA) * Bach 3-CT-6 (2x 7-RA) *

Bird Wing Imperial The Bird Wing or later, Bird Wing Imperial was a light sport biplane of the 1920s and 1930s. Development The first Bird Wing took McCrum and his assistants 63 days to build at a cost of US$12,000. The prototype flew over 5000 passengers over a p ...

(option) *

Briggs Briggster Briggs may refer to: People * Briggs (surname) * Briggs (rapper), Australian rapper Places ;In the United States * Briggs, Nebraska, an unincorporated community * Briggs, Ohio * Briggs, Oklahoma * Briggs, Texas * Briggs, Virginia * Briggs Lake, ...

* Cessna AC * Curtiss Robin J-1 (7-D) * Fairchild KR-34B (aka KR-34B-1) 7-RA * Fairchild KR-34C (7-E) * General Aristocrat 102-D proposed 7-RA * Kreider-Reisner C-4 7-RA * Kreider-Reisner C-4B 7-D * Marine Water Sprite Marine Aircraft Co, Sausalito CA. - 7-E *

Maximum Safety M-2 In mathematical analysis, the maxima and minima (the respective plurals of maximum and minimum) of a function, known collectively as extrema (the plural of extremum), are the largest and smallest value of the function, either within a given r ...

7-RA * Maximum Safety M-3 7-D *

Neilson Golden Bear The Neilson NC-1 Golden Bear, aka Neilson Coach was an American, three-place, high wing cabin aircraft, flown in 1929. It did not go into production. Design and development The Golden Bear was a high wing aircraft built around a welded steel tu ...

Parks P-2 The Parks P-2, powered by a 150 hp Axelson-Floco B engine, was a biplane designed and built at the Parks Air College in the United States circa 1929. A change in engine type to the Wright J-6 resulted in the Parks P-2A, which was ultimately ...

(option) * Schroeder-Wentworth 1929 monoplane 7-RA * Sierra BLW-1 7-RA * Sierra BLW-2 7-RA * Spartan C3-166 7-E * Stearman C3L 7-RA *

Thaden T-2 Thaden is a municipality in the district of Rendsburg-Eckernförde, in Schleswig-Holstein, Germany. Geography Thaden is located about 25 km southeast of Heide in a rural environment. North of the community runs the Kiel Canal The Kiel Ca ...

7-D * Timm C-165 Collegiate 7-E * Timm K-100 Collegiate 7-RA * Towle TA-1 7-D * Towle WC Amphibion 7-D * Travel Air 4-U conversion to 7-RA, 7-D and 7-E by O W Timm Aircraft Co. * Triton Water Sprite, Triton Aircraft Co, Sausalito CA. 7-E * Warren CP-1 7-D

Specifications (variant)

References

{{DEFAULTSORT:Comet 7 radial 1920s aircraft piston engines Aircraft air-cooled radial piston engines