Would this be a successful product to design for Mx5s?

[Fraser.G]

Hi i'm thinking about designing a Dynamic Rear Wing for my Mx5 for a school project.
And I would love to know if there is a market for an affordable, DIY, Dynamic Rear Wing for The Mazda Mx5 89-05 MODELS?
Feel free to let me know what you think.
Cheers,
Fraser.G

[lizard]

From a design engineer's input the effort you would need to put into the design of the wing and testing including wind tunnel @ $500 a hour along with the market your aiming at I would say not a good idea . But why not make one for your own use it would still be a cool project.

I wish someone would make wind deflectors that sit above the wind screen and deflect air down onto my face (?)

[Fraser.G]

From a design engineer's input the effort you would need to put into the design of the wing and testing including wind tunnel @ $500 a hour along with the market your aiming at I would say not a good idea . But why not make one for your own use it would still be a cool project.

I wish someone would make wind deflectors that sit above the wind screen and deflect air down onto my face (?)

Hmm good point, im using a free CAD software that simulates a wind tunnel right now, and ive been able to download mx5 templates to test their aerodynamics, so far its been working pretty well. However i like you idea, could be another fun project.

[Lokiel]

From a design engineer's input the effort you would need to put into the design of the wing and testing including wind tunnel @ $500 a hour along with the market your aiming at I would say not a good idea . But why not make one for your own use it would still be a cool project.

I wish someone would make wind deflectors that sit above the wind screen and deflect air down onto my face (?)

Similar to what you want: http://www.coolbreezescoop.com/

[Magpie]

lizard I have one on my hard top, whilst it gives you the air it is noisy at highway speeds it is silent when wearing a helmet on the track. Lokiel's suggestion is much better if you run with the top down.

Are you looking at the wing itself or at the mechanism to control the wing?

Personally the mechanism would be the focus as it could mounted to any shape wing.

Something like a trim control?

http://www.rosner-tdl.de/english/aviation-1-landing-flaps-drive.htm

Flexible wire shaft to push/wind the wing on its mounts?
http://machinedesign.com/mechanical-drives/aircraft-has-right-stuff
http://www.sswhiteaerospace.com/flexible-shaft/applications.asp

Look into the way aircraft control its surfaces for ideas.

[Fraser.G]

lizard I have one on my hard top, whilst it gives you the air it is noisy at highway speeds it is silent when wearing a helmet on the track. Lokiel's suggestion is much better if you run with the top down.

Are you looking at the wing itself or at the mechanism to control the wing?

Personally the mechanism would be the focus as it could mounted to any shape wing.

Im was planning to design a wing and the mechanism to control it. Ive recently been looking into possibly controlling it manually, without electrics, but i will need to conduct some tests to see what kind of force i'm going to be dealing with..

[Magpie]

The specs for the APR CTC200 that I have mounted on my car are here http://aprperformance.com/racing-product/gtc-200-adjustable-wings/.

I can go through some previous data and get some more info on actual downforce experienced on the track if it will help.

[Fraser.G]

I can go through some previous data and get some more info on actual downforce experienced on the track if it will help.

Yes please, that would be really helpful!

[stuart1]

The specs for the APR CTC200 that I have mounted on my car are here http://aprperformance.com/racing-product/gtc-200-adjustable-wings/.

I can go through some previous data and get some more info on actual downforce experienced on the track if it will help.

Further to Magpies reference this link http://aprperformance.com/racing-product/gtc-series-adjustable-wings/ has some good reading for the APR GTC200/300/500 wings.

Up to 120MPH the 300 generates the most downforce by a good margin but the surprise is how much a small gurney flap increases downforce plus extends the wing's stall angle point.

Personally I think the forces required to change the angle of attack of a high downforce wing manually at high speed have been under estimated but maybe a movable gurney flap could be achievable.

Having said that what is the point as a change in rear downforce would also require a change in front downforce to maintain balance as without this you run the risk of understeering off the track and/or locking your front brakes.

Rear downforce is easy to induce but front is not so the amount of rear you run is always a result of how much front you can get.

Downforce comes at the cost of drag so you need sufficient power to overcome this drag and some cars are faster without wings.

Not so simple but the attached link will provide some good reading.

Good luck with your project.

[Magpie]

stuart1 raises some very good points. In the testing of my wing it was very easy to overpower the front end if I set the wing at 15° AOA and did 160 kmh. For my car I have found the best position is about 1° AOA (with a gurney flap). This does not reduce max speed too much and still generates sufficient downforce for corners. Having a MX5 with limited power the decision is one of how much advantage do I get by increasing the car's drag or would the horsepower be better used elsewhere. The key is to generate downforce without increasing drag and the gurney flap is one of these tools. Reshaping the air flow over the car is another. Hence why having a mechanism to control the wing is more important than the wing itself, at least in my mind.

Therefore if using a manual system, using something like this would allow quick precise adjustment albeit over a limited range may reduce the risk of having the car unbalanced:

[madjak]

Bit of a novel:

With wing designs, the lift to drag ratio can be very different depending on the profile.. ie if it is a dual element wing, how effective are the end plates, how clean is the airflow etc. Part of the challenge of aero design is getting the best possible lift to drag ratio whilst getting the required downforce to make the lap time quicker.

In the case of my wing, at it's ideal angle of attack (AoA) I think the lift to drag ratio is 13. This means if its generating 130kgs (1300N) of downforce, it's only adding a drag of only 10kgs (or 100N). If I change the AoA to a steeper angle, the wing will get a ratio of 10 so it will generate 2000N of downforce but will double the drag to 200N. If I go past it's maximum AoA the wing stalls and generates massive drag with very little downforce (ie air brake)...

Items like the gurney flap and endplates change the efficiency of the wing slightly. The wickerbill/gurney flap is a must have... as it reduces drag, increases lift/downforce and also effectively raises the stall angle of the wing. The end plates stop the high pressure faster air underneath creeping around the ends of the wing to get to the low pressure air on top. An effective design keeps the airflow laminar and improves the downforce across the whole wing.

The 3D wing designs like the APR wings are so that the air that's travelling around the side of the car hit a wing section that has a higher AoA than the air that's sweeping down over the roof. The problem with an MX5 is that these 3D wings are more designed for Porsches and fastbacks rather than our hardtops. In our cars, the wind is fairly turbulent, so ideally you need to mount the wing high and up out of this air. I'm not sold that they are better on our cars than a standard 2D wing profile mounted in clean air.

With a DRS system, you generate maximum downforce and drag when braking and cornering and as soon as the car exits the corner and no longer needs traction the wing drops down to a lower downforce state with the lowest drag for straight line speed. F1 teams effectively do this by removing the second element of a dual element wing and making the wing a single element.

The idea of an air brake, is that you operate at a certain downforce level as default so that you get good cornering, and move the wing to stall when braking. Supercars do this so that it takes some load off the braking system. I don't think it necessarily improves lap times. It also only really works well at very high speeds.

To make the wing move dynamically under load requires the pivot point to be correct. I'd just place it slightly rear of the center of the wing section and design it so you can move this point easily if required (ie multiple holes) and then figure it out on the track. Even if you are generating 200kgs of downforce, if your pivot is central to the wing it will only a little force to move it.

here is a video showing how to make active aero with relatively cheap devices. Regardless, by the time it's all finished you are looking at a $1000 project I would expect.

https://www.youtube.com/watch?v=0Rprz9YVe1s

In this case, the RaceCapturePro could be replaced with an arduino board or something similar that has some IO. However, if you are going to be mucking around with active aero, you really need a decent data logger to track the effects... you'll also need GPS / G-force sensor and a controller with scripting to handle the logic side anyway. I'd suggest not reinventing this aspect and just go buy a RCP ($480 US) if you have the budget. You can build all this, however it is a project in itself.

This hooked up to a relay module and either a windscreen wiper motor, or headlight actuator from the pop-up lights and you can control a rear wing via either a manual input on the dash or some automated logic.

[Fraser.G]

Thanks once again for all the comments. However now im contemplating whether this is actually a good idea for my car. Last time i took my car to the track i was at wakefield and i managed to get up to 145kph on the straight. Im starting to think that my car isnt fast enough to need a serious wing, and the cost of doing all of this is starting to be abit out of my budget, as i would need to buy myself a hard top as well to maximise windflow to the back of the car..

[madjak]

A wing will help any car be faster, but that's only really true when you are already at the limit of traction on corners. It's corner speed and braking that is increased by downforce not speed down the straight.

Any project combining motorsports, electronics and construction is going to get expensive!

Why don't you just do a front splitter, canards or some other easier option.

[Fraser.G]

A wing will help any car be faster, but that's only really true when you are already at the limit of traction on corners. It's corner speed and braking that is increased by downforce not speed down the straight.

Any project combining motorsports, electronics and construction is going to get expensive!

Why don't you just do a front splitter, canards or some other easier option.

I think that sounds much more do-able, and it wont cost as much. Ill just need to figure out a way to improve their design.

[lizard]

A wing will help any car be faster, but that's only really true when you are already at the limit of traction on corners. It's corner speed and braking that is increased by downforce not speed down the straight.

Any project combining motorsports, electronics and construction is going to get expensive!

Why don't you just do a front splitter, canards or some other easier option.

I think that sounds much more do-able, and it wont cost as much. Ill just need to figure out a way to improve their design.

7 years at uni may help