Sunday, December 28, 2014

Project Dragon (Drakan Spyder) Update #8: CFD, Tooling & More

We've kicked off production of Project Dragon - now officially named Drakan Spyder.  For 2015 we are accepting only 10 orders - 5 of which are sold as of Dec 15, 2014.  This Blog update will discuss the additional CFD work, body tooling, light housing concepts and interior switch details.  We have entered our commercialization phase so things are getting even more exciting!

Aerodynamic Characteristics: 
We asked Dennis Palatov to conduct a Computational Fluid Dynamics analysis on our completed Spyder body to determine lift/downforce, drag and radiator cooling flow.  Solidworks Flow Simulation 2012 was used using the solid models supplied by our partners Zukun.  The simulations were run with and without wings.  Test conditions were set at 100mph at sea level with a moving ground plane and rotating surface of the tires.  The Palatov D2 has undergone both simulation and observation so we have a good 'control' for comparison.
Test results:  Without wings the car creates about 138lbf of total lift and 295lbf of total drag.  This is very similar to the D2 numbers.  Radiator cooling flow also appears to behave similar to the D2.  This is especially critical as we want to ensure adequate cooling exists in hot conditions as we previously tested.  With wings the Spyder achieves 15lbf of downforce in the low rear wing position and with the rear wing raised 5" total downforce goes up to 122lbf.  Total drag is 307lbf (low) and 322 lbf (high), respectively.  The windshield clearly causes some reduction in overall effectiveness of the rear wing.  We'll eventually offer a race version of the car that would lack the windshield.    

Conclusion:  This analysis suggests that the Drakan Spyder design has benign aero characteristics in the base (no wings) configuration.  With wings, modest downforce can be achieved with enhanced high speed stability.  The drag numbers also suggests that top speed may be limited to ~155mph.  We think we may be able to achieve both downforce and reduce drag if we consider using a dual element rear wing as we had designed for the Atom2.  See it: HERE.  Because 155mph is not really enough...;^)

Bodywork: Lancair

We visited our body supplier Lancair in early Dec. to kick off the bodywork tooling.  Lancair are a composites manufacturer who specializes in carbon fiber airplanes.  They are located in beautiful Bend, OR.

We spent the day working with them to finalize our schedule.  Our plan suggests the first body will be ready in March for test fitment.  The first plugs are underway (as of this writing) and expected to be done in Jan2015.  The engine lid is shown below.

engine lid
Lancair produce their airplanes with prepreg carbonfiber.  They also use a product called e-glass that is a prepreg fiberglass that is strong and light.  We will use this material on the majority of our body.  There may be a couple applications like our windshield base that will be done in carbon.

Interior switch panel: Concepts

Our test mule had rudimentary switches that we used to run our car on the track.  Placement of the switches has been scrutinized and we've landed on a basic layout that we feel should work for the Drakan.  The switches will be very simple with back lighting.  
This switch panel will sit to the right of the steering wheel with the 'sector111' logo centered over the gear shifter.  All the switches are easily within reach of the driver.  Ergonomic considerations can be as challenging as performance targets when designing a car.  We've spent an inordinate amount of time sweating the details.  The final panel will be prototyped in January.  

We have spec'd in Hella DOT legal lights for all areas of the car.  LED lights have been used in all instances except the headlights which are Bi-Xenon.  We have developed a housing concept that took inspiration from tactical tools like flashlights, gun scopes, etc.  

We are getting these prototyped as well to see how they look and work.  Ultimately our goal is create lights that can be removed fairly easily for track use.  Overall, I'm very happy with our design and can't wait to get them.

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