On display at the Bournville Submarine Day was this RC Engel U Boat Type IX (Type 9).
The Type IX U-boat was designed by Nazi Germany's Kriegsmarine in 1935 and 1936 as a large ocean-going submarine for sustained operations far from the home support facilities. Type IX boats were briefly used for patrols off the eastern United States in an attempt to disrupt the stream of troops and supplies bound for Europe. It was derived from the Type IA, and appeared in various sub-types.
https://en.wikipedia.org/wiki/Type_IX...