I made a real test drive now. Disc brakes are just great by the way. Driving the trike was big fun. I drove it without the streamline this time which had a nasty dissadvantage. I never got so dirty from riding a bicycle before.
Last picture is from the new rear fork with some parts still to be welded.
I took the bike out again. I have been lining up the wheels a bit. It doesn't feel too stable in going straight while using force at higher speeds. Maybe the front wheels should be moved a little more forward. I'll let you know the outcome.