The maximum speed of a Blokart is NOT limited by drag but by stability. That fact should be obvious from all the gyrations in the video - but if not - I suggest you read:

Hyperwind Sailing on Snow, Ice, Land and Water. Kenney, B.C., 2017, Catalyst 52, J. Am. Yacht Res. Soc.

It is available now to Society members on their forum, if you want to join the Society. Otherwise, it will be available on a pay-to-read basis shortly.

Sorry, I forgot.

It's: www.ayrs.org

The notice for Catalyst 52 and link to it is on the AYRS home page (at www.arys.org) but an index or table of contents is not included.

The picture on the cover is from the paper.