Whittle was without doubt one of the world's greatest engineers and his invention changed our world for the better. At a time when his engines could run for 30 hours between overhaul, German engines could only run for 30 minutes before being stripped down and completely rebuilt. So yes, Whittle's engines were the first practical demonstration of jet propulsion.
And you donīt think that has had "something" to do with the materials situation in Germany at the time ?
So Sir Frank Whittle changed the world for the better and Dr. Joachim Pabst von Ohain didnīt....?