the game as its now tends to have some problem towards loading and updating chunks as you go thru them.
you see, the starmade univers/map is constantly spining and turning and since all sectors spin and rotate at difrent speeds(fast near star, slow on the edge) it get limeted, and asuming a block is 1m by 1m going 50.000 km/h seems a bit out of place, and having lightyears for spead would be theoretical inposible(even whitin si-fy universes) to manuever at that speed, and fly like that would in all instance slow down time.
you can go faster, as a mater i\'ve seen speeds of 100+km/h but its a temporari stop-gap for not being able to deteremen accuretely how fast you go (yes you can see, but you cant say use only 50/25% power for the engine or something) i think there would be someware a setting you need to change
also the univers is still to scaled down for going faster to(small planets that are just laggy disks and such)