Does Catto make a prop for the J-3 Cub? I contacted them but got no response as of yet.
The following is from the Type Certificate data sheet A-691.
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/ec36f12e6e139c5b8625785c006c09c8/$FILE/A-691%20Rev%2034.pdf
101. Propeller - Wood (fixed or adjustable pitch). +9 lb. (-51)
This also:
IV. - Model J3C-65, L-4H, L-4J
Propeller Limits
Static r.p.m. at maximum permissible throttle setting (No additional tolerance permitted):
(a) With A-65-1 engine: Not over 2300, not under 2000.
(b) With optional engines (Item 311C) and propeller Item 2 or 101:
Not over 2300, not under 1950.
Diameter: Not over 81 inches, not under 69.7 inches (with fixed pitch wood propeller).
Not over 74 inches, not under 72 inches (with propeller Item 2).
Entry in the aircraft log: Installed Catto model xxxx wood propeller in accordance with T.C. A-691 Item 101. Weight change negligible. signed Joe Blow 1234567 A&P.
It is a minor alteration since it is defined in the type certificate.