47-47-13: Hartzell Propeller Hub Counterweight

47-47-13 REPUBLIC: (Was Mandatory Note 11 of AD-769-2.) Applies to Model RC-3 Aircraft. To be accomplished not later than next 100-hour inspection or January 15, 1948. If the Hartzell propeller hub model on your airplane is HC-12X20-3, determine the counter weight length and position on the hub in order that the hub designation can be amended as necessary in accordance with the following: (a) Plain counterweights 4.650 inches in length - the designation HC-12X20-3 is unchanged. (b) Notched counterweight 4.50 inches in length - add suffix letter "C" to designation so that it reads HC-12X20-3C. (c) Plain counterweight 4.50 inches in length - a 1/8-inch slug must be added to these counterweights and suffix letter "A" added to the hub designation so that it reads HC- 12X20-3A. Any of these hubs on which the slugs have not been added to the counterweights must be removed from service until the counterweight slugs are affixed. Revise the reverse thrust operation placard as follows: For airplanes with 6A8-215-B8F engines, Serial Numbers 23001 to 23280, inclusive, and HC12X20-2 propeller: WARNING - Reversing propeller in flight prohibited. Operate reverse lever in low pitch only. Maximum 1,750 r.p.m. in reverse pitch. For airplanes with 6A8-215-B8F engines, Serial Numbers 23001 F to 23280 F, inclusive, and 23281 and up and all -B9F engines and (1) HC-12X20-3 or 3-A propellers: WARNING - Reversing propeller in flight prohibited. Operate reverse lever in low pitch only. Maximum 2,300 r.p.m. in reverse pitch. Or (2) HC-12X20-2 or -3C propellers: WARNING - Reversing propeller in flight prohibited. Operate reverse lever in low pitch only.