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Uas 300Zx Vs. Standard 300Zx Aero Analysis And Results

Boosted Zed
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Boosted Zed Mentor

Boosted Zed

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UAS has recently begun using Computational Fluid Dynamics (CFD) software to aid us in designing elements of our aerodynamics package.

Unforunately time and cost constraints make a true to life simulation a difficut task to achieve, as ideally every component down to the smallest washer should be modeled into the software and then animated to garner accurate results.

STANDARD CAR

FULL CAR SIMULATION

The above two videos show the flow trajectories over the UAS Zed and a standard 300ZX respectively. Though the models are rough they are enough to indicate significant changes in aerodynamic downforce and drag. The figures in the above simulations showed the UAS Zed generated five times more downforce than the standard 300ZX at 200km/h.

To give the exact measurements that is an increase from approximately 50kg to almost 280kg. Drag also increased but only by a factor of two with the standard car measuring 100kg of downforce to the UAS car's 230kg.

The UAS rear wing is a fantastic example of how we use the software to aid our design despite our time constraints. By focusing on a small area in isolation, we can more clearly judge how changes will impact our drag and downforce characteristics.

REAR WING

In this instance it was found that adding a 15mm gurney strip to the larger lower rear wing increased the overall downforce by a significant amount ( ≈ 11%). This produces an extra 14kg of effective weight on the rear at 200kph, with only ≈3% increase in total rear wing drag.

We have also been able to generate numerical data using the program. Doing so allowed us to find a number of interesting results.

On straights, the wear wing of the UAS Zed has a tendancy to flex under the downforce load. This change in area has an impact on the overall downforce of the wing.

circuit_battle.jpg

Using CFD analysis we were able to simulate a number of different instances. We simulated a straight wing, one with the top wing flexing to touch the lower and an instance of both flexing to the same degree. We did this at both 200km/h and 100km/h simulating a worst case scenario through high and low speed corners.

As can be seen from the tabulated data this flexing causes a drastic change in the dynamics of the wing. Both downforce and drag are significantly reduced as the wing starts to bend.

graph.jpg

On straights this is beneficial as it has the same effect as the adjustable rear wing systems used in the 2011 formula 1 season, if to a lesser degree, reducing drag so we can achieve a higher top speed.

In low speed areas it is slightly more detrimental, however it should be noted that at these speeds overall downforce is significantly lower and as such flex is reduced causing a corresponding reduction in overall downforce lost.

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Boosted Zed Mentor

Boosted Zed

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what is the wing made of/? that is some serious flex

Carbon fibre epoxy resin with sandwich foam core. It flexes because it has 200+kg downforce.

We recently added an aluminium right angle gurney strip to the trailing edge of the main rear wing blade. This will stiffen it up a little bit, although the flex is not all bad as it creates maximum efficiency at low speed where it needs it most. At high speed as it bends it reduces efficiency but also less drag.

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