3. My car is a road car, not a racer, so my primary aero requirements are for less wind buffeting, and a more pleasant driving experience up to about 65mph. Mostly this car is for going around 25mph curves at 40 on sundays. So Here's what I've done and have planned.
Next, I have plans to build a complete, flat bellypan from the nose to the firewall. The BEC design doesn't require a large transmission tunnel, only a channel about a 4" wide for the two piece driveshaft to go through,Welcome to the group.
The tunnel does add some rigidity to the chassis. Narrow tunnels give less strength. You might be able to use that fan drive shaft idea to pull air through the tunnel. I think on most cars the fan wouldn't be able to be very large in dia. because of the tunnel size.
so the bottom of the car will be completly enclosed and completly flat. My tunnel is set up with the top held on with machine screws into threaded holes in the upper tubes. Being able to remove the top cover has come in handy a few times already when I was working on the rear end etc. The bottom of the tunnel is open.
The hood has no holes vents or bump outs. This is the way I like it. However I do have plenty of room under the hood and behind the radiator to put a snow shovel-like air dam inside the engine bay, that could be made to channel air out of the engine bay, if I think it is benificial to do so. Undecided on that. (sidebar thought- rather than a snowshovel, the airdam could resemble the cow-catcher on the front of a train, and "plow" air out both sides.Unless you have a sealed duct that directly guides the air from behind the radiator to an outside vent it probably won't matter too much if you have an inside shovel thing or not. And if the you do use a sealed duct I would imagine that the heat from the exhaust could get things very hot inside the otherwise sealed engine compartment.
I would be concerned about how the warm air from the radiator is going to escape at low speeds or sitting at stop lights. I'm using the original motorcycle fan and it really doesn't move a lot of air. But it has never come on either.
The very hot headers got my hood so hot above the pipes that I couldn't keep my hand on the hood above them even with the vented area around the air scoop. I put an internal head shield above the pipes and now the hood temperature is bearable.
Formula 1 cars use side pod radiators, and exit air to advantage flow charicteristics, so it may be possible to use the heated air to provide some direction/order to the turbulent air swirling around uselessly behind the front wheel/suspension?
I'll have to think about that.At least one Locost has a single protruding vertical vent on each side of the car near the windshield to allow air to escape from under the hood. But I'd want to check and see if it's a low pressure area first. If you don't plan on driving that fast you may not develop enough pressure differential where you need to worry about the exact placement.
Last, I will have a Bikini top that extends from the the top of the winscreen over a purpose built "rib" over my head, and over the roll bar and down to the back. I have no idea how it will behave at 60MPH, but it will be there to keep the sun off me on long drives. I have a similar top on my beach buggy. It bulges alarmingly upwards in the middle at high speeds. Enough so that at 90 MPH it actually would pull the windshield back a few inches!! The rear and sides of the top are completely open.
The windshield is much taller than a Locost windshield. When I am at the front of the line at a stop light I can't -see- the light. I have to stick my head out the side to see what's going on. If you use a 4 or 5 point harness in the Locost you won't be able to move around that much. I can't even lean forward enough to adjust the right side mirror (and barely enough to reach the left side mirror).
In the end, I hope the lower profile, enclosed flush belly, fold-down screens/brooklands screens will yeild a pleasant, and fairly smooth and comfortable environment for sunday driving, in the 40-70MPH range. That's the plan anyway. The Tonneau will be used when it's cold, and the Bikini top, when the heat is too much, otherwise these will be stowed. So for me Aero is about comfort, less buffeting, perhaps less wind noise, and an enjoyable place to do some spirited motoring on winding two-lanes without excessive fatigue from getting blown around.
All your ideas sound good. I've noticed that most of the air buffeting I get is from around the side of the windshield. My windshield glass is only 9" high inside the frame. I really don't feel that much buffeting from over the top of the windscreen since the air is thrown upwards.
I think when you put the wind shield down you may find that there is just way too much wind buffeting with the Brookland screens unless you are wearing a helmet. But they will look great even if you don't use them.
Keep us posted on your plans/build.