The "copper" material is in fact burnt metal as the front part is the exhaust manifold for the Bristol Hercules Engine. The Exhaust of the engine was actually faced to the front of the engine and formed a collector ring around its front.
Please note a few points of etiquette. First, would all contributors please use their real name and/or their actual e-mail address. All contributions are welcome but please refrain from political or abusive comments. These posts will promptly be removed from the server.