Quote:
Originally Posted by JulianEdgar
And regarding the original topic, I intend doing a video soon on Kamm tails.
The latest SAE paper* on the topic (2020 published! - very rare to find new stuff published on the original low drag shapes), basically debunks so-called Kamm tails as a way to low drag.
(*I found the paper through a reference that Aerohead made to it here - thanks very much for that.)
The SAE guards their copyright fiercely but there is no copyright on facts, so I will be able to summarise the paper in my own words without issues. (But not use any of their diagrams, unfortunately.) |
1) They do mention that, ' the drag reduction from the elongated tail varies almost linearly with the reduction in cross section area' ( which is in keeping with Lay's, Kamm's, Reid's, Heald's, and other investigators ).
2) their comment about ' car-like' shapes implies that they don't know about Jaray's body cross-section morphology.
3) The Kamm-Tail did produce Cd 0.12, and that's without any active suspension/ variable ground clearance or wheel fairings.
4) They also discuss how, ' little data is available on the effects of streamlined tails on non-axisymmetric bodies, whether representative of road vehicles or not.' Guess they don't know about EcoModer.com.
5) The 'Windsor' body they investigated doesn't represent a 'real' automobile either. So that's problematic.
6) I wouldn't recommends NASA's Project Shoebox as an example of boat-tailed 'squareback' vehicles, as it's architecture is problematic.
7) Spirit of EcoModder demonstrated up to a 62% drag reduction by just following the old timers.
