Republic RC-4 airliner


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26 May 2006
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the Republic RC-4 was a twin engined airliner project,powered by two


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RC-4 is Republic Entry in Short-Haul Competition
American Aviation, September 1964

Republic Aviation Corp.'s entry in the Federal Aviation Agency's short-haul transport competition is a twin-engine, high-wing design bearing some resemblance to Fairchild's F-27.
Designated the RC-4, the aircraft would be powered by two 800 eshp PT6-A (SEM-117) turboprops built by United Aircraft of Canada. It is designed to accomodate 14 passengers and 500 lb. of cargo at a gross weight of 16,610 lb. or, in a high-density configuration, 20 passengers and no cargo for a gross weight of 17,244 lb.

First flight of the prototype could be made 20 months after the initial go-ahead. About 11 more months would be required for FAA certification. After certification, a production rate of five aircraft per month could be reached in 10 months.

A summary of the non-recurring RC-4 costs includes $10,390,940 for design and development and $6,489,430 for tooling— a total of $16,880,370. List price of the aircraft would vary with the number of units ordered. But Republic is estimating prices as follows, with the first figure including recurring costs and the second figure including non-recurring costs: 100 aircraft, $575,351 ($744,155) ; 200 aircraft, $500,535 ($584,940) ; and 300 aircraft, $460,176 ($516,444). The company also suggests three different electronic packages for the RC-4 at estimated costs of $44,240, $61,350 and $84,770.

The Republic proposal also includes inboard and outboard flaps and lift spoilers. In-flight reverse thrust could be added if the requirement is sufficient.

At the present time, two alternate versions are being offered. One, with an eye to the military, no doubt, is an ambulance configuration which would carry 10 litters plus two attendants. The second carries its total fuel, 540 gal., in tip tanks only. A rear-loading version is also optional.

A 20-passenger configuration could carry a 4000-lb. payload over a stage length of about 680 miles, more than adequate for most short-haul operators. A 3500-lb payload could be carried 800 miles.

The 14-passenger configuration with 500 lb. of cargo and a cruise altitude of 8000 ft. would have a direct operating cost (DOC) per airplane mile varying with the initial cost of the aircraft. At a unit price of $800,-000, for example, the DOC per aircraft mile would range from 85c for a 200-mi. stage to about 75c for a 600-mi. stage. With an aircraft unit cost of $600,000 the DOC per aircraft mile would be approximately 76c for a 200-mi. stage and 68c for a 600-mi. stage.

Under the same 8000-ft. cruise altitude conditions but in a 20-passenger configuration, the DOC per aircraft mile for the $800,000 unit price would be about 86c for a 200-mi. stage and 164 for a 600-mi. stage. With an aircraft unit cost of $600,000 the DOC per aircraft mile would range from 77c for a 200-mi. stage to 68c for a 600-mi. stage.

The DOC per aircraft mile for a $700,000 aircraft unit cost falls almost exactly between the costs listed above for both configurations at all stage lengths.

The total aircraft cost less fuel (DOC per aircraft mile) for the $800,000 unit ranges from 99c at a block speed of 140 mph to 78c at a block speed of 180 mph, and down to 65c at 220 mph. Total aircraft cost less fuel for the $600,000 unit would run from 86c per aircraft mile at a block speed of 140 mph to 70c at a block speed of 180 mph, ant to 58c per aircraft mile at a block speed of 220 mph.

Assuming the average cruise speed of the 14-passenger and 20-passenger versions, 204 kt. and 202 kt. respectively, to be 203 kt., and that this speed could be made good as a block speed, the $800,000 aircraft would have a DOC per aircraft mile (less fuel) of about 60c with the $600,000 aircraft having a cost of approximately 55c per aircraft mile.


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Two more puctures from
Cradle of Aviation Museum



That's first time I see project of this aircraft, another item in "RC" (Republic Commercial") line, incuding SeaBee RC-1 and RC-3
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