DRS (Drag Reduction System)
DRS (Drag Reduction System)By:
Patrick Antar 7664257 Lachlan Wilton 7656890 Theodore Johnson 9741194
Daniel Loi 9501258
Taking a step backwardsWhat is a DRS and why?A Drag Reduction System on the rear wing helps with reducing the overall drag generated by the car with the help of elevating a flap element, reducing its angle of attack.
It can significantly increase the straight line speed of a racecar.
My group and I are assessing its effectiveness and determining how much of a benefit it could bring to this years Team Swinburnes electric racer.
DRS gif activation
Rules and RegulationsFor rear wing:
In plan view, no part can be further rearward than 250 mm rearward of the rear of the tires.Cannot be wider than the outside of the rear tires measured at the wheel hubs.Cannot be higher than 1.2 m above the ground without a driver onboard, from the side view.
Rules and Regulations For activation mechanism (Compressed gas, etc..)
ConstraintsTotalweightlimitof5kgswithDRS.Thedesignshouldsatisfyallthecompetitionrules.Notmorethan10mmofdeflection,measuredatfurthestpointfromthechassis,in anydirectionatmaximumloading.Shouldnotinterferewithothercriticalmountingpointsontherearchassis.Theaerodynamicdesignshouldnotincreasetheoverallaerodynamicdragby5-10% ofthebaseline(withnowings (+DRS) but with undertray)model.
Sub-SystemsActuator MountingLinkageInputHigh/LowInboard/Outboard# of pointsDirectionMaterialElectricalLinearHighInboardSingleCompressionWireRotationalLowOutboardDualTensionSolidMagneticN/AN/AN/AN/AN/AFluidPneumaticHydraulicManual
Initial design evaluation gave us a total of approximately 32 different potential designs.
To reduce the design decision process instead of each team member accessing 8 designs covering different areas of study, each team member has been assigned a single area of study that covers a number of potential options.There are three subsystems required, for the car.An input motion, a way of converting that motion into an appropriate vertical linear motion and a way of transferring that force into a rotating
Linear pneumatic cylinder
ManualLevers & FootpedalsNo additional energy source.Cabin Space.FluidSelf Contained, linear.HydraulicHeavy, messy, flammable.
PneumaticCheap.Relatively light. Linear motion.Clean. (Air)Compact.Well understood.
ElectricalRotational.DC motors, Stepper Motors, Servos.Small, cheap, light, accurate, rotational to linear motion possible.Linear Actuator.Microcontroller, drain on the battery.Electromagnets/SolenoidsLow force, Expensive.
ComparisonGOODBADBADGOODGOODBADBADGOODBADGOODBADGOODGOODBAD1-35 MPa0-800 KPa
AccuracyCleanlinessControllabilityFlammabilityInexpensiveLeakage/failureLubricationPressure regions PNEUMATICSHYDRAULICS
Our choice: PNEUMATICSIt is the best for our application after looking at the comparison.There still is a plenty of decisions to make:
Cylinder sizePorts sizeInlet and exhaust valve flowsAir pressureBore and length of the hosesLoad against which cylinder is working
We also have the choice between a single acting or a double acting cylinders.A single acting with spring return seems to be best for our application
Other factors (Calculations, activation method)
Means of activationPushing effective areaPulling effective areaEffective area for a given force
SummaryDRS activated by the press of button and will spring back to its initial position once the driver lets go
Pneumatics provide an safe and relatively light and inexpensive means to achieve it
Packaging will be in one of the side pods away from the driver
Strategically deployed to last the entire competition.