Quote:
Originally Posted by Ecky
The more I think about it, the more I like your CRX trailer and find my design converging on it, aerohead. It's an elegant solution.
This is what I'm up to now:
I decided it would be possible to keep the rounded nose so long as I didn't slope it at the top, which would require that I cut two fitting ovals. Turning angle is down to 65° if I don't set the nose back, but I'm thinking of constructing the trailer with a plywood frame, bottom, and lid, and siding that you'd use in an RV shower which would give and return to shape if it hits the bumper; plus it's waterproof. 7' length keeps the slope shallow enough that I should hopefully have reattachment of air before the tail end, and lets me cut it from two 4x8 sheets of plywood. I don't think I'll be able to easily round the top edges like you did.
What I haven't decided on yet is what to do about the fenders and underside. As I understand, extending the fenders down to cover the front of the tires should provide aero benefit, but that might be a bit ambitious for my first iteration.
EDIT: I miscalculated the volume of my design #2 in post #33, it should have been 22.5 cubic feet. Volume of this design is ~32 cubic feet.
EDIT2: Should I lower the front an inch or two, do you think? The leading edge of the cylindrical nose is within the template, but moving back, it's not. |
I like the idea of efficient use of materials,and I think your nose will basically slip into the wake area as you've drawn it.There'll be turbulence due to the gap but I think you'll have reattachment everywhere except the belly.
With enough length,even a sharp-edged box will regain attached flow.
The front of the trailer will be embedded within the Insight's wake.Here's a shot of a 1st-gen Golf/Rabbit wake.
The gap-drag is an unknown quantity.Here you can see the drag of a Clark-Y airfoil as a function of gap location,etc..
As to the fenders and bottom,I've gone ahead and enclosed mine,with full sides,complete belly pan,and I'm about half-way with complete wheel fairings.
You might just do simple skirts down to where a belly pan with diffuser might be,and some simple fairings before and after the wheels.
Or just skip it,get a baseline for whatever you do,then later,if you add the bottom cleanup,you can compare performance to see what difference the bottom made.
On low-drag cars,the wheel drag alone can constitute half of the overall drag,so the 'cleaner' you get,these naughty bits become more and more important.