Cox Wing F15 Falcon propeller

Hi,

Just found a 3 blade safety tip prop that came originally from my old Cox Wing F15 Falcon, it came with a small red spinner, and measured 4.5" diameter. I wish to use this for breaking in my new Cox engines. I don't know what's the pitch, nothing written on the prop.

Anyone know the pitch of this prop? don't know if its suitable for breaking in new engines , I've heard some say we need slightly light load prop for break-in process. The reason I wanted to use it just because I found that its balanced perfectly, no need to re- balance again.