Here's my issue: all aero parts have a L/D ratio, and we obviously want that to be as high as possible. But it is not infinite and adding downforce will generally add drag. Of course, as you have pointed out, a more-efficient design has a better L/D ratio and may therefore be able to provide more downforce with the same drag as a less-efficient design. There are several parameters with the NSX-R wing that we could criticize as impairing its efficiency, namely those related to its profile and position.
Since I don't know the profiles of the NSX-R wings (each of the aftermarket manufacturers seem to have their own profile) I find them hard to comment on (or, more accurately, allow my brother to do so). From the pictures I find online, some seem to have a Gurney flap of sorts (which increases efficiency and power). This implies to me that they are at least considering the wing's profile. Without a proper set of photographs or (better yet) a cross-sectional drawing, it is difficult to characterize the profile of existing wings. That said, having talked to my brother, it is nearly certain that he could design an improved wing. One thing I'd like to know in this regard is whether rules are a concern? If not, for example, the wing could incorporate aspects to improve it's L/D ratio at high speeds. Also, is there an objection to a multielement wing?
Regarding the wing's position, you proposed the height as the second major design driver here. My brother pointed out that a much bigger improvement in efficiency comes from moving the wing back off the edge of the decklid, so that the pressure reduction under the wing does not create a corresponding lift on the car. As I understand it, you are not interested in that idea. This could be for compliance with some set of rules, but if not then I still think the idea is sound. It wouldn't at all preclude moving the wing up; in fact, I envisioned a movement in both directions, to gain both separation and at least some degree of nonoverlap with the decklid. If efficiency and power is our purpose, the I don't see why we would ignore one of the most significant ways to get that.
All of the NSX-R wings I have seen in person, from an OEM NSX-R from Japan, to the Spoon NSX-R GT that I drove, to the Seibon, Downforce (the wing I currently have on my car), and many others at meets which I don't know who made them are pretty much all different. However the Seibon and Dowforce are some of the best looking and closest to the Spoon NSX-R GT wing out there. The biggest issue with the NSX-R wing is the trailing edge. What looks like a 'gurney flap' is a little moulded 'lip', but the lower (and more important) side of the wing terminates with about a 1.5" almost vertical trailing edge. Don't get me wrong, the NSXR wing IS functional but I question if it acts/was designed more like a deflecting spoiler than a true airfoil which speeds up the air under the wing and creates a low pressure area for downforce.
Pretty much any airfoil design will be more efficient than the NSX-R, and depending on its cord, thickness, camber profile will dictate its characteristics for a targeted speed (which is usually 40-160mph for street cars, or more likely 40-120mph). I don't think anything exotic is necessary and my idea to bring the costs down so this 'Hybrid' isn't overly expensive, is to use a common pre-made profile and have it cut or made to the width of the trunk. However I am very intrigued and would love to see what your brother comes up with in terms of a new design.
I considered a multi-element wing and it could even be incorporated as an add-on with a bigger endplate/upright design to even be removable, but for me, a single element closer to OEM look was what I was personally aiming at first.
In regards to wing location, as I said before, the higher the wing is off of the trunk, the less the lifting effect on the trunklid.
While moving the wing rearward does accomplish the same thing, it greatly departs from my personal direction of this "hybrid" wing design -which is to look similar to OEM/NSXR. There's also a secondary effect to mounting the wing further back: It lifts and unloads the front of the car due to leverage and requires even more front downforce. If a wing is mounted right over the rear tires, it will have minimal lifting effect on the front wheels. Leverage can be a good and bad thing, while a smaller wing could make the same rear grip as a big wing when mounted far out the back of the car, it lifts up on the front of the car like a see-saw. We really noticed this in the most recent revision of the FXMD FX750 V6.1 that we set the BW track record with:
My own car, which is entirely stock, understeers. Obviously I need to address that to the extent possible before throwing aero parts on the car, and changing the suspension seems like a good candidate. Moreover, a stiffer suspension is likely required when adding well-designed aero parts to the car. Adding a vented hood would be a good way to start with front aero, no doubt. I suppose my thought was that adding rear downforce is going to unbalance my car more, so I'd rather at least have a plan for front downforce first. But I'm willing to continue on with this wing anyhow, since I like the idea of something that doesn't look like a GT wing. I also looked forward to working with my brother on a project. He is too busy to follow threads on Prime, but remains interested in the project.
This project will require a fairly substantial investment for tooling and other costs. And, while I'm confident in my brother's work, it will not be a windtunnel-tested design. I asked Arron about that and he estimated that a shoestring-budget approach to windtunnel testing would start around $100k. That was after pushing him on his initial figures. So, no windtunnel.
Do you have the stock alignment? What if you trail-brake? -would it understeer then? Short of an S2000 or Miata, the NSX is one of the most neutral balanced chassis out there. If you give the car inputs to understeer, it will understeer. If you give it inputs to rotate or oversteer, it will kick the rear end out. Either way, I'd suggest getting your alignment in order before packing aero onto a car, especially front aero -since cars need much more rear than front downforce. Just adding a wing alone will not unbalance your car. You might not have much angle in the wing, but there's nothing wrong with running just a wing without a splitter. Many race series don't allow very big splitters and the cars run massive rear wings. As far as stiffness goes, I doubt any of the wings (even most GT wings) we are talking about will be making more than 4-500lbs of downforce, so increasing the springs probably isn't necessary or that crucial unless you still have stock springs. I look forward to hearing more updates from you and your brother.
It seems like if we are disconnecting two pieces, then it wouldn't be any more difficult to simply replace the uprights with different ones. This would allow more flexibility in position. And if a drawerslide-like mechanism (to simply move the wing back a chord) would give equivalent performance but wouldn't require any unbolting, then I would still prefer that. The difficulty, as I have tried to point out above, is that we don't know what will give equivalent performance. So interchangeable uprights would obviously permit the greatest postfabrication adjustability (and would allow your system of overlapping uprights if that is what you prefer).
My 2pc upright/endplate design is still a work (or a thought) in progress. Nothing has been fabbed up yet, just sketched out and discussed -which is why hearing input from others on what they want, or how it could work is helpful and nice to involve the community, especially those who are looking to have one made for themselves. My first idea was simply 2 bolts on the upright, unbolting them, and bolting them in a different higher location. I didn't think about a sliding mechanism -which would be easier than completely unbolting the wing from the base plate but I am still looking for a height change design with a peak height and look similar to the red ADAC NSX:
One more thing: should this wing have a brake light?
I thought about this many times and for me, i'd say no -if it changes the underside of the wing and affects it's efficiency. I thought about a strip of LED lights mounted within a gurney flap which would 1 - utilize a gurney flap and 2 - have minimal affect on the wing's performance.
I wonder if we are not trying to solve the impossible dream?
No drag, lots of downforce and street frendly?
I once raced against a race only NSX and the guy was able to pull away from me in the corners despite both of us on slicks.
His suspension setting and lower weight must have played a big role but most probably the aero aswell.
The car was very close to the original Hondas raced at Le Mans.
My point is: is there much to gain without going to a wing at least the size of the one on the pictures?
When I was let to drive the car, I thought it understeered quite a bit but maybe I wasn't going fast enough?
Pretty much anytime you add downforce via a wing you inherently add drag. The biggest thing that stands out between his car and yours is a much larger wing (I've never seen your wing in person so I don't know if its a true airfoil or similar to stock or the NSX-R in profile) as well as a pretty big front splitter. I think if you had a real wing on the rear of your car (without or especially with a front splitter), you'd be able to hang with him in the corners -or be much closer to it.
The splitter, side skirts, roof inlet, and rear of the car looks a bit different from the LeMans NSXs. Do you have any more pics of that car?
To answer your question: I'm not sure if you would get a gain by going to an NSX-R, however with my goal of a "Hybrid" wing with a real wing element mounted the width of the trunk, you could get as much downforce as a full size GT wing. Disclaimer: Due to the narrower width of the "Hybrid", you would need more wing angle to create the same downforce as a wider wing -which increases drag to a degree. So while you would have the same downforce with the Hybrid as you would with a full-size GT wing, you would have slightly more drag. Ideally, you want the widest wing possible with the least amount of angle of attack (for reduced drag) -but the goal of the Hybrid is to have full-size downforce capability (far more than the NSXR) while remaining as wide as the trunk and accepting a slight drag penalty for the reduced width.
It sounds like I may be right and you'd have to swap the wing-mounted uprights in order to go full height??
