Piltdown was hoax designed to spoof some British anthropologists. They had a particular view of brain/locomotion development, so the hoaxer gave them what they wanted to see.
Anthropologists in other parts of the world saw things differently, and soon began to poke holes in the Piltdown finds.
The only people still using Piltdown for anything are anti-evolutionists trying to pretend that all hominid finds are lies. And that in itself is a blatant lie.
Lets try a test; can you cite a second fraud in hominid evolution?
(Warning: Nebraska Man does not count. That was a mistake by one individual.)
(Hint: the creation "science" websites will lie to you, so don't trust them.)
I'm shocked. Shocked!