The term double-propeller plane is identified in base64 scheme by the sequence ZG91YmxlLXByb3BlbGxlciBwbGFuZQ==, while the MD5 signature is equal to c72a59dd162d204d57942fa1e16ca9c4. The ASCII encoding of double-propeller plane in hexadecimal notation is 646f75626c652d70726f70656c6c657220706c616e65.