Reverse Trike Fender Treatment

[drmiller100]

Hello,
I'm new to the site. I am building a reverse trike powered by a Honda Civic Engine (Dx 1500 to start with).

Cockpit is 33 inches wide, and enclosed.
Outside to Outside of front wheels will be 60 inches.

So on each side, will be 14 inches, with the front tires the outside 6 inches or so.

Leaves 8 inches by 26 inches tall "duct" on the inside of car, and outside of engine.

This is 210 square inches per side, or 410 total. which is 2.5 square feet.

I thought about bicycle fenders, but they look like crap In My Opinion. So, I want a hood over the top.

I am totally willing to leave gills at the back.

So, the question is: Am I better off to close off the front as tradition dictates, or put huge ducts through the car like this one does:

Another company to make a reverse trike? - Page 2

[JasonG]

Usually a full front is close to exposed wheels and suspension in final drag.
Thr F-1 guys spend $$$$$$ making open wheels work aero wise.
Have you looked at Q R Rileys trimagnum and XR-3 ?
Currently helping a buddy finish a tri-mag, bad thing is its RWD
I've been eyeing the same powered by a Saturn S series.

[drmiller100]

the XR3 is a LOT better aero then the tri-mag.

One of the rules I know is NEVER shove air under the car - always try to keep air out from under the car.

My frontal area looks to be about 12 square feet. If I can use the 2.5 feet, it might be significant. I'm even giving a bit of thought to making "ducts" and using them to duct the air back through the opening.

[ChazInMT]

Hey Dr Miller, Welcome to Ecomodder.

I think you'll find in this forum most people are not too worried about what you do in the front of your project, just so long as it is a rounded shape. Rather, you'll want to focus your attention on the back of the project, what does the air do after reaching the widest or tallest part of your trike. You'll want to strive for following the ideal aero dynamic template from the highest/widest point back.

I think initially ducts would be better if you can make the suspension aerodynamic. If you have a bunch of stuff hanging in the slipstream that is round, that will not be optimal. Also you need to consider the level of difficulty when building fairings/fenders vs a single piece body. You also need to consider what the motivation for this is. Is it Style? or is it Aero and MPG Efficiency? In using a 1500cc engine, I'm guessing optimum fuel efficiency is down the list a few points behind acceleration performance. By "enclosed" do you mean bathtub or fighter jet?

This looks like a good idea to start with here of all the stuff I looked at.



Anyway, this looks like fun!! I'm certain you'll have no shortage of help in here for aero support.

[drmiller100]

Hey, thanks for the welcome!
That car has a tail pretty close to what I will be doing.

I would guess that car has a cockpit close to 48 inches wide. Mine will be 33 or so wide. Mine will be half way between side by side and tandem - the passenger sits offset and slightly behind the driver, giving the passenger plenty of room, but keeping the body narrow.

When I look at the car you show, there will be a LOT of turbulence off of the front fenders. When I make the cockpit narrower, there will be even more turbulence.

My goals are to make the car do everything for everyone of course! I am using the Honda DX engine to start, because I have one. I also have a head/block for a CX, and I have a 5 speed from a CX with the super long gear ratio.

Goal would be 1000 pounds or so, 12 square foot frontal area, .30 CD.

My ultimate goal is 1000 pounds, 100 horsepower, and 75 mpg at 75 mph.

Lean burn, and maybe nitrous in the future for another 100 horsepower!

Dream big!

[JasonG]

Sounds like you are headed in the right direction !

The black trike also needs an enclosed cockpit for better aero.
If the front fenders tapered into the doors it would be much better.
Like Chaz said, worry more about blending back in and less about the front.

Having worked with the fiberglass over foam, it is easier and stronger that it seems.

[kach22i]

I suspect the red one is using the front part as a wing for downforce.

Automobile pictures by kach22i - Photobucket


I do like the black design on that page (and far above) the best from an Industrial design aspect.

[ChazInMT]

Here's a fix for the fenders



And a little larger version of the pic. (Ecomodder only displays photos so big and things get hinky)

Bigger Version of Black Trike

[drmiller100]

heck, that is SIMPLE!!!!!!!

a mark of a genius is simple solutions when complex would work!

[drmiller100]

on my front fenders, lets assume the high part of the fender is right over the tires.

How sharp of an angle, or what curve, or how do I build the back side of that as steep as possible back down, but yet ensure the air stays attached?

In other words, how do I shape the tops of the fenders using redneck engineering?