Here. Check it out. It was wild.

 

That is some downforce there! ^^^

I have posted elsewhere about losing an endplate as a result of bonded-in attachments being levered out by these forces. Lesson learned.

I would think that making a proper gurney tab might be a better solution, and I have have seen photos of that, possibly in this thread.

 

Haha yep, and your guess of about a 8" span being disturbed looks spot on. I had already decided, but yeah, I'm going swan neck.

 

I have been pondering making our end plates deeper like yours are here, wasn't so sure it was worth it. Drew some up but never got round to cutting them out....

That's a pretty good (amazing) indication of function right there!

 

Aerodynamics. It really does the things.

My aluminum endplates with gurney flap flex, albeit much less than that since they are far more rigid.

An old post of mine in this same thread back in 2015:

 

I'm currently running 3mm ACM, not sure how it would stand up to that....hoping okay.

will have to make the bigger ones and use action cam.

 

I apologize if this has been covered but cannot seem to find the answer. How do you measure wing AOA with a gurney flap? It is measured from the top of the flap to the front of the airfoil right?

 

It really doesn't matter, what's important is that whichever way you measure it you do so the same way each time. This ensures your setup notes are consistent. The only reason you'd need to worry about measuring the wing the same way someone else is doing it is if you're trying to copy/share setup info... but you're much better off just finding the balance that is right for your specific car and making your own setup notes because no two cars are identical.

That said, it's generally agreed that you measure AOA with the gurney included since that is effectively part of the airfoil. But, there are cases where you may not want to do that - for example if you have a removable gurney flap or gurneys of different heights like I had with my old COT wing. Then I would always take AOA measurements without the gurney and my notes would include the wing angle plus the gurney flap size.

 

Ok cool. Another question. At what point do you want to stop decreasing AOA and change to decreasing endplate size or removal of the gurney flap?

 

That depends on the airfoil being used, as well as other strategic considerations such as track specifics, ruleset, etc.

 

Let me rephrase my question. how would you decide what to change? Any adjustment to the wing will make a change in the downforce to drag ratio. So how do you know whether to remove/intall a gourney, increase/decrease endplate size, or increase AOA? Will increasing AOA net a worse downforce/drag ratio than an alternative? So do you want to max out (for example, endplate size) before increasing AOA?

 

just for my info:

what orientation do you want for alumalite on a splitter? the stringers running perpendicular or parallel to the length of the car?

 

Parallel to the length of the car. You want more stiffness to resist bending about the Y axis.

 

thank you sir

 

Probably better question for the aero discussion thread on another forum, but without doing any of the googling prior to asking, why not just integrate the end plates into the uprights?

Lightyear I believe you have already tried this. but I can't remember/didn't look to see if you commented on the difference.

I'm sure I am missing something and the answer is simple.

 

Cause most of the time the wing is way wider than the car. Of course you could do curved/bent endplates,

 

I believe mounting the wing via the end plates is the best idea. Even a swan neck will create some disturbance. End plates are there anyway, so there is no additional drag unlike wing mounts. Plus yaw/slip angles make things worse again for conventional mounts. Only problem is the wider and further back the harder it becomes to fabricate something that will work.

 

End plate mounting works A-okay, see F1 for example.
For a Miata this will require mounts that are more complex to manufacture and likely heavier, so swan neck mounting is a more a practical solution.

 

Here is my old set up.

 

This is the upright that bolts in behind the bumper sides. It's a multi layer foam cored hand laminated carbon fibre part.