phizzalot

iTrader: (3)

Holy smokes i see Jesus

Vehicle336

I see Darth Vader.

hamflex

iTrader: (18)

What does a hot wing look like? haha

and yes i see jesus too..... haha

Balrok

iTrader: (15)

So the Jesus was holding up his weight, not the wing

ssg_petty_210

iTrader: (13)

What did the stock evo wing get rated as. I was told at 80 mph, it added 800lbs of downforce. I am no aero expert so I have no clue. If anyone could shed some light on that, it would be much appreciated.

Balrok

iTrader: (15)

And also include data on what the Vortex and "wicker bill/gurney flap" adds. I remember some mag article claiming it was +30% downforce or something.

KevinD

iTrader: (56)

it takes a seriously huge wing to make that much downforce as i mentioned the APR wing does around 500lbs at 120mph, and downforce is exponential, so at 80mph its signficantly less. and the stock wing isn't nearly the width, cord length, AOA, or element profile even compared to the APR.




so lets see the downforce numbers for this wing a guy standing on it tells me nothing. we wont see centralized loads on a wing, its going to be distributed loads across the span. plus, for the time and effort spent on the carbon, i would like to see a better AOA adjustment, and possibly provisions for active aero actuators.

EVOlutionary

iTrader: (38)

The OEM wing is somewhere around 80# @ 100mph.

The guy standing on it tells you the same that it tells you when a guy stands on a splitter. That it is structurally strong but nothing else. Unfortunately that has erroneously become what the internet warriors see as a test of the product's merit or performance.

I already told you that in the rear world we see distributed loads, not centralized, so your quotation of the amount of downforce the APR wing can make (2nd post in this thread) has nothing to do with its structural soundness. BTW, the correct #'s for APR GTC at 120mph is 457# downforce and 54# drag - in a free stream computer simulation. So lets see the REAL WORLD downforce #'s for your wing on your EVO??

EVOlutionary

GTABurnout

iTrader: (1)

Mechanical engineer here...

First question is will the trunk support this type of down force? Or will this need to be mounted to the body some how...

Second on the all carbon up rights (maybe on the Aluminum ones as well) what is the type of insert is used. Composites and inserts are a huge issue in the aerospace world.



I am also concerned about the joints where two pieces of carbon come together. Is that a epoxy only joint?

Also what is the plan to mitigate corrosion between the aluminum and the composite structures? I am sure your aware of galvanic corrosion potential between the aluminum and a carbon.

KevinD

iTrader: (56)

the structural soundness of the APR wing is ok, because we run it on one of our road race cars and it is still there

i haven't fitting the wing with a load cell or Pots on the shocks because its not my car, but the CFD data is enough to sell me on a product. it tells me it was at least engineered, and not just fabricated. its that same reason i'm not jumping on the GTC-500 wing, which by common thinking would be better (higher number right?), but it actually makes less downforce. Drag for me is irrelivent as i have plenty of power and still have plenty of acceleration on the top end of the tracks we run. additionally, i've modeled various controllers for an active wing in matlab. i've considered doing it when i get a wing so at the very least i would like the ability to impliment it.


the Voltex wing appears like a better wing, being two elements (more AOA), but its price is a bit high... at that rate i would just make my own. which ever wing i end up getting, i will prolly make my own uprights regardless, and i plan on making it sit very high, and as far back as allowed to get as close to a free stream as possible, with provisions for active aero.



so about the CFD numbers on this wing your showing us, give em up! or better yet, how about on car numbers

jerdeitzel

iTrader: (9)

I have seen some DHP products that are just fantastic pieces. But, from a non technical standpoint the mounts on this wing look like crap.

For reference i just installed a Kognition wing and the mounts look to be much better thought out. And you can stand on this one also!

EVOlutionary

iTrader: (38)

How much does the Kognition wing weigh with mounts?

Stock trunk will support that much downforce, no problem. I had an even larger wing on before that made more total DF with much more drag and it held up just fine. Now a carbon fiber trunk is a different story. My current setup has a custom strengthened CF trunk with more central wing mounts rather than the OEM mount location.

As for inserts - I am assuming you mean through the bolt holes? No inserts used, but I don't remember seeing most common CF wings for auto racing using inserts. I think, unlike the aerospace industry - it is not necessary for the forces and average lifespans we see . . .

The two pieces of carbon joint you are talking about - is that the upper and lower wing halves or the mounting tab that sticks out the bottom of the wing? The mounting tab goes all the way through the wing and is attached to the upper surface as well as the lower surface via epoxy. This mounting tab used to be made of aluminum but the newest wings have it made from carbon. Has held up fine to over 180mph so far that I know on one customer's Lister.

Where would the aluminum to carbon galvanic corrosion be? It looks like the aluminum mounting brackets at the trunk to upright interface are epoxied to the uprights. Should be a thin film of epoxy between the two surfaces. Even if they were touching directly - how long would it take to this reaction to cause a significant weakening of the material?

EVOlutionary

iTrader: (38)

The DHP is available in dual element with the top element being adjustable or fixed. Adjustable is heavier and more $$ of course.

You may want to talk with AMS. Their TA1 car started off with an APR wing, but then they went with a smaller unit mounted higher and farther back.

I am pretty sure DHP doesn't have any CFD, just scale wind tunnel testing when the wing profiles were developed for a FSAE program. When the full scale wind tunnel testing of my car is complete I will be sure to send you a link to the article. You could help sponsor it if you like

EVOlutionary

KevinD

iTrader: (56)

an FSAE wing designed without CFD???? blasphemy!!!


our wings were 4 element and we kept making them farther and farther apart, and bigger and bigger, and always made more and more downforce. were were making 1G of downforce at 60mph of course if you make your rear wing to big and can't get the matching downforce up front the balance will be wacky...

usually though, before you run a wing design through production and wind tunnel testing you would test it and refine it on CFD. Fluent is even free or heavily discounted for FSAE teams (at least when i was doing it, it was).

hamflex

iTrader: (18)

......
Hello my friends...

OK, first off I want to clear one obvious thing up... I am no engineer, I love cars, I race cars, and I do my research on parts. I do though, know when I over step my boundaries and this is one of those cases. I emailed David last night and brought up all of your concerns and questions. As a driver and representative of DHP Composites, it would do his company no good if I were to litter this forum or any other forum with my pure ignorance on the topic of aerodynamics. And this is not a stab at any one on here, so do not think that. I just don't want to present myself as someone who preaches what I read but does not fully understand



Here is his response that I got this morning,

Hey thanks for the info I also checked out the site this morning and believe we can respond as I have below. It is tough because we have spent lots of time and money developing what we have today (your wing design and how its built) and I feel its important to answer some of the questions but I also don't want to give away any of our trade secrets because we do it differently than any other manufacturer on the market besides dedicated race teams........

DHP Composites was started in my FSAE Days we had access to a wind tunnel and CFD programs to do the work on designing and refining our wing profile. This was first done in CFD to get a base line and to better understand what happened to the wing in different situations the single element and double element wings then went into the windtunnel and we tested on a 1:1 scale. With this data we found a correlation between the cfd and windtunnel to help us further refine the wings. With that being said this data I feel is much better than strictly CFD Data and we are working on plans of putting an EVO in the windtunnel within the next year to further investigate exactly how much downforce the wing is actually doing on the car.

Countless wings have been run by end users and everyone that runs the wing tells us these produce much more downforce than the competitors with that being said the closest competitor I would have to say is Kognition and they do build some nice wings.

The construction on the wing is proven and has held up at 190 mph speeds without a problem the way the parts are put together is more than just an epoxy joint but I don't feel we need to divulge this information since it has taken us years to develop it. What I can say is the the wing itself is a true monocoque construction and we don't have to use any spars or chords other than the mounting brackets that are sandwiched inside the wing. These mounts used to be made out of aluminum but we have now switched over to carbon to make them stiffer and also lighter. These and the mounts from the car do have an effective insert so that they will not crush or have any bolt movement.

The mounts in the pictures (from Ryan's Car) are strictly for R&D and are the first ones we ever made, so yes the surface finish is not up to par with our normal production parts but the next ones will certainly be, we also feel these are probabley the lightest stiffest wing mounts that are on the market, pictures attached they saved close to a pound over the aluminum ones. and once bolted up to the trunk seem to be much stiffer both vertically and laterally than the aluminum ones. These mounts are also attached mostly in double shear to the trunk so that significantly helps the stability and structural integrity of the package. I am sure Ryan will be giving some feedback once he has had a chance to get his car out. If anyone needs more adjustment out of their wing these mounts can be changed so that the rearward bolt hole to the wing is replace with a turnbuckle that will give you basically infinite adjustment out of the wings AOA.