Quote:
Originally Posted by ennored
Percent of wake area reduction is NOT proportional to drag reduction. There's some plots of the difference here at ecomodder - somewhere.
You need to draw up some ideal and proposed boattails then compare that to a plot of drag vs. boattail truncation. Throwing random numbers out: 20% of an ideal boattail is worth a 50% reduction in drag (but only like a 10% reduction in area). Again the real numbers are here at ecomodder - somewhere.
(I'll search a little. See what pops up for me.)
|
At the bottom of this table is the boat tail which AeroStealth will be constructing.
Here's a relationship between wake and Cd derived from Mair's boat tail research.If you look at the 'skinny tires' line,you get a sense of what the wake's relationship to drag can mean.
One unknown that we're aware of is,that the Prowler's roofline is cambered downwards,unlike the Ahmed body from which the tail is derived.So it IS an unknown quantity.But without a $50,000 research grant from DARPA,it's the only thing that will fit Aero's budget.It will be the 1st 5th-wheel in the world to be streamlined this way.We'll get some valuable real data from it.And it won't cost taxpayers a cent.
We know of better boat tail designs,but they're 2-magnitudes higher in fabrication complexity and expense.