Reaper 935 'RSR' Project

[Reaper930]

I'm trying to catch up Serge!!!!!!

End Caps are done

[RarlyL8]

Looking good!
Please explain the end cap design.

[Reaper930]

The endplates are there to:

a) break up vortices from the wing where high pressure and low pressure air will meet
b) straighten air flow from turbulant area slightly behind center of rear quarter panel
c) enlarge the wing's effective area by the following (Formulas out of Joseph Katz's New Directions in Race Car Aerodynamics):

Effective Aspect Ratio (AR_effective) = Actual Aspect Ratio (AR_actual) * (1 + 1.9 * (endplate depth/span))

With this formula I figured that a 178 cm wing x 29 cm wide with endplates measuring roughly 29 cm by 48 cm (.2286 cm thick) will yield a wing with an effective size of roughly 287 cm.

Endcaps such as these can be found on the RS Spyder, Audi LMP car etc.

[Flieger]

I know the function of endplates / winglets but I am curious as to the function and aerodynamics of your endplates profile with the curved cutout on the bottom. Does it catch the air or control the exiting air? Does it improve stability dynamics when yawing?

Interesting

[Porsche911nick]

sweeeeettt nice project!!!

[Porsche911nick]

Originally Posted by Reaper930

Partial update, Porsche Motorsport steering wheel goes on with quick release & North Hollywood Speedo gauges.

We'll soon have the gauges in the car, but here are some pics, just got the shot of the gauges from Hartmut, and he is a wonderful guy to work with.

Shot showing the dish, I have short arms so this will work well. The gauges shown in the car are not my gauges...


The dash is going to be freshened as well, all in due time.



Look ma! No wheel!


Alcantara's don't match well - might have to reupholster the seats.


Gauge Shot...just beautiful. These are the guages redone from original ones that Hartmut created for me, he did a FANTASTIC job! Great guy to work with.

OUFFFFF wish i had thoseee baby's!! WOW

[Reaper930]

Originally Posted by Flieger

I know the function of endplates / winglets but I am curious as to the function and aerodynamics of your endplates profile with the curved cutout on the bottom. Does it catch the air or control the exiting air? Does it improve stability dynamics when yawing?

Interesting

The cutouts at the bottom of the wing are there to reduce the brittle edge area that will be under tremendous stress due to buffetting and yawing. This reduces its effective area but at the same time ensures that it won't be broken.

And yes it corrects the air flow and reduces turbulence.

[Reaper930]

Porsche911nick: Glad you like it

[Porschekid962]

Looking good! For additional strength and a very small bit of aero help, get some lengths of carbon with a 90 degree radius to it nothing more than a 1/4 inch tall and mount it along the vertical on the trailing edge of the endplates facing away from the car. You can also put it on the trailing edge of your upper element, wicker, wickerbill, gurney, what have you they can be effective. I thought some on the endplates would be good as it would provide some stability to the piece. If you do it, use Titanium or Stainless hardware, regular steel and aluminium dont play nicely with carbon they will rust and or corrode (Galvanic effect).

[sand_man]

WOW! She's really coming together, Reaper!

[Reaper930]

Weidmans is slowly making headway with the 935 rear rims, they had to be trued before cutting the inner rim halves and rewelding as there were a few flat spots, all very minor.

The order is to polish the rim halves when completed and the shop back in Van Nuys will do the final painting of the centers with the same satin black as the body.

For now, rims waiting to be cut:

[austin552]

Been about a week, what's happening???

[Reaper930]

Sorting out the fuel system and wiring harness...getting the brake setup handled as well as tackling the suspension. No word yet on the wheels, but i'm sure it will be worth the wait!

[dave egan]

Beutiful "Stunning" project!! can't wait to see it finished!!! If you don't mind me asking, and if so , no offense, taken whatsoever, what kind of dollars , (aproximately) , will this project end up costing , when all is said and done?? , Is a car like this when finished , ''insurable""? , I just am in awe of your project , and really wonder if it 's between 75K and 100k or is it more like 100K and 150K? Great concept!!!

[Reaper930]

Dave,

Thanks for the kind words, and yes it is insurable. Agreed value insurance is how I'm having it covered.

Total the cost of the car is in the higher range of the $100-150K margin. I certainly didn't expect that getting into it...

[BoxxerSix]

Might I ask where you purchased your carbon wing airfoil? I've got a need here for a similar part Oh and what is the total length if it(minus the spill plates on the sides)

[Craig 930 RS]

The en-gi-neer in me, sorry not to be a pr!ck, yet:

Does the rear element actually have a functional aerofoil section?
Those side extensions will be rather unstable and will shimmy like a Mother, just a friendly FYI -

[BoxxerSix]

Originally Posted by Craig 930 RS

The en-gi-neer in me, sorry not to be a pr!ck, yet:

Does the rear element actually have a functional aerofoil section?
Those side extensions will be rather unstable and will shimmy like a Mother, just a friendly FYI -

I thought the same thing but back on page 15 towards the bottom there was a cross section view of the foil sans the spill plates and it looks to be functional.

[Reaper930]

Adam: The wing is from GT-Racing which has his wings built by a specialty shop and that's all they do from what I understand. At 0 degrees it provides as much downforce as a conventional wing at 10 degrees. Its setup currently for minimal drag as I plan on doing some top speed runs with it as soon as I take delivery of her. With the combination of the tail base and upper wing element I'm looking at some pretty substantial downforce for the rear which is what I need without over powering the front end.

The wing is 70" (177.8 cm) in length and 11" (27.94 cm) in width. Its a very lightweight part for its size as well. Its name through GT Racing is the "Predator Wing" named after its design from the UAV (Unmanned Aerial Vehicle) extremely efficient wings.

Craig: No offense taken, the winglets do appear a bit flimsy in photos but Crawford Composites supplied the pieces and after much discussion we're confidant that they will not shimmy due to their extremely ridgid nature. They're constructed of .090" thick structural carbon weave, not that bling crap often used. The weave isn't very pretty up close, but this car is function over form.

The notch on the bottom of the winglet is to reduce stress on the leading edge and spread it over two stress points greatly reducing the amount of "push" and "pull" effect on the overall surface.

In future the winglets will be raised to accomodate a two stage wing with an additional element on top of the current element and the winglets will hold that element in place.

Profile & Curvature:




Winglet Weave:

[spence88mph]

way cool, has it been asked already why no cage or are you getting to that?
Top speed runs.... please get a cage, love the build by the way, gets better with every post.