When in doubt, add more wings!

Here’s an update on Jim’s “X-Prize Aztec” — looks like three new front-wings have been added… I mean no offense to Jim’s honest efforts, but as I understand aerodynamics, wings increase drag as a part of increasing downforces, which is the exact opposite of what you’d want to do if your goal is a high mileage vehicle.

11 Responses

  1. Tom Alvary says:

    Actually,I can see what Jim is after. He’s got little wings on the three highest pressure spots on the car, apparently to try to break them up and allow lower pressure laminar flow to stay on the body beneath them. Interesting. Of course, whenever you create some turbulence its anybody’s guess what is actually happening, particularly off the tips of those wings. This car needs to be driven around with yarn taped all over it…

    The side window treatment, however, looks spot-on to me, and really cleans that area up. It could be done in .080 lexan very easily…

  2. Tom Alvary says:

    Actually,I can see what Jim is after. He’s got little wings on the three highest pressure spots on the car, apparently to try to break them up and allow lower pressure laminar flow to stay on the body beneath them. Interesting. Of course, whenever you create some turbulence its anybody’s guess what is actually happening, particularly off the tips of those wings. This car needs to be driven around with yarn taped all over it…

    The side window treatment, however, looks spot-on to me, and really cleans that area up. It could be done in .080 lexan very easily…

  3. Jim(Xprize Aztec owner) says:

    Hi- the wings are called turning vanes, or barge boards in F1. The purpose being to keep flow attached where a transition wants to seperate it and become turbulant. Also there are bumper regulations which the front wing addresses. The license plate lays flat under a cover between the front wing struts(5 mph @ 100!). These are mock ups in cardboard, you have to picture them with some style in carbon. The side window has the rear view mirror inside it. Jim

  4. Jim(Xprize Aztec owner) says:

    Hi- the wings are called turning vanes, or barge boards in F1. The purpose being to keep flow attached where a transition wants to seperate it and become turbulant. Also there are bumper regulations which the front wing addresses. The license plate lays flat under a cover between the front wing struts(5 mph @ 100!). These are mock ups in cardboard, you have to picture them with some style in carbon. The side window has the rear view mirror inside it. Jim

  5. Jim(Xprize Aztec owner) says:

    P.S. Also the front wing can be used as an air brake and front traction increaser. Whats the record for 100-0 for a street car(not a winged monstrosity race car on gumballs)? I plan to test the wings by running the car with a restrictor plate so it runs flat out at say 70 or 100, assuming it will go a 100 with the 1200cc single port motor. Then run the car with various size wings, vanes,trim tabs, turbulance generators, surface finishes,etc.and settings and find what works. You have to go where nobody’s been if you want to find something new.

  6. Jim(Xprize Aztec owner) says:

    P.S. Also the front wing can be used as an air brake and front traction increaser. Whats the record for 100-0 for a street car(not a winged monstrosity race car on gumballs)? I plan to test the wings by running the car with a restrictor plate so it runs flat out at say 70 or 100, assuming it will go a 100 with the 1200cc single port motor. Then run the car with various size wings, vanes,trim tabs, turbulance generators, surface finishes,etc.and settings and find what works. You have to go where nobody’s been if you want to find something new.

  7. Tom Alvary says:

    Agreed, except that when you are where nobody’s been, your likelihood of getting what you want goes way down. Still its a noble effort.

    IMHO, the barge board at the windshield root is way too narrow. You’re going to introduce unpredictable wake turbulence in a very high pressure area, which extends about to the curved part of the windshield on the sides. Shouldn’t your barge board wrap to at least there?

    Also, the top wing seems like a big drag to me. From this angle it looks more like a Fowler flap than a barge board. It just isn’t keeping pressure off the ridge made by the windshield gasket. Wouldn’t you be better off shaving the gasket there until the transition is perfectly smooth, then putting vortex generators just aft of there on the roof to keep the flow laminar?

    Just a thought, but I’m concerned you are creating too much drag. F1 designers happily buy stability and downforce at the cost of increased drag, where power is abundant and specific fuel (energy) efficiency is secondary.

    If this were my car (and who knows, one day it might be…) I would extend the rear like a LeMans-tailed Porsche and work on the underbody and espectially a long diffuser area. This seems to be where the most drag and lift reductions can be had, especially at modest speeds with an already pretty slipper shape.

    Anyway, understand this is no criticism at all of what you are doing. Its so interesting. Have at it…

    Tom

  8. Jim(Xprize Aztec owner) says:

    Hey Tom relax. You are looking at some old card board mock ups. The belly pan is adjustable(convex,flat concave,in motion?). The tail is a whole other exercise after the nose is dialed in. What does IMHO mean? I assume you have some tunnel data or lap time improvements to back up your advice. Photo’s would be nice. I’ve built and tested in the low speed tunnel at A&M, and models at UCLA years ago. I’m not going to show any results untill the race because current XPrize cars can be cleaned up and could show up with my ideas if they have to. You only have to get 75 MPG in the qualifiying race to make the final race. I’m only interested in an order of magintude improvement, so I have to discover some inter relationship nobody knows about yet. Jim

  9. Jim(Xprize Aztec owner) says:

    P.S. Here’s where the dodo gets really deep. I would like to try boundry layer suction over the nose to try and get laminar flow over the first third of the car. By using a 6″ narrower front end the front wheel skirts can be faired in permanently. The head lights can be covered and moved to the side windows ahead or the rear view mirrors using the new small quartz lights. Another possiblity is to cover the body and belly pan with say a quarter inch soft foam with a flexable skin to absorb turblance and keep the whole body attached. Or I might forget this whole exercise and sell the car if I can’t find sponsorship for the X Prize race by Feb entrance deadline, and just work on the carbon motor.

  10. Harley says:

    Hey Jim, very cool, you guys lost me with the laminar flow and all,but if I can add my 2 cents, I would leave the headlights where they are and just make clear covers for them like the old XKE’S had. The Caribee has a similar style front nose, an old friend of mine made covers for his and picked up a couple mph’s in the quarter mile, of course it was a 9 sec.race car, but he ran with and without and they made that much difference. How does this race work? Is it an actual speed event or just to see who can go the furthest on a gallon of gas? What about weight? Are diesels allowed, guess I should google it as I have a lot of questions, good luck with that, hope you find a sponsor. Harley

  11. jim linck says:

    The X-prize never came off so I sold the Aztec. There was never an explanation of why the contest was cancelled. I assume it was because the economy was so bad or no real producable street legal crash worthy car can can get 100 mpg in real world driving. It’s amazing how much time and money was put into prototypes for a shot at the million dollar prize that are just useless now. Jim

Leave a Reply

Your email address will not be published. Required fields are marked *