Need 40 year old Casement Window Operator

I'm looking for a replacement casement window operator for a house that is 40 years old. The old mechanism has no manufacturer's label or mark of any kind, neither does the window. A major problem is that the operator arm is 11" from pivot point to center of wheel and I don't find an 11" arm anywhere. I'm attaching a picture of the part in the hope that someone might be able to identify it.
Thanks, Robert

Dave, thanks for your response. I guarantee you that it's not 13-1/2 inches. But I can understand your skepticism, I took it to several local hardware and window dealers and they had trouble believing it even when the part was right in front of them. The hardware people all said I had no hope of finding a replacement. The window dealers all insisted I had to install a new window.

I think your suggestion of a 9-1/2" operator as a substitute is a good idea, and a lot cheaper than replacing the window. Moving the track would not be a problem. Thanks a lot for your time, I appreciate it very much.

Robert