b'Engineer Innovation | Aerospace & Defenseenough thrust. On the other hand, reducing the drag in horizontal cruise flight needed a thin propeller cross section to minimize the area of propeller facing air resistance. How do you design something to be thin and thick at the same time? The answer: design optimization with Simcenter. In simple terms, Hazen needed to analyze hundreds of duct designs to choose the best compromise, something beyond the wildest dreams for any testing. When looking at designing a new duct, we looked at quite a few by hand by changing important duct parameters. Figure 2: Simulation of the V-BAT aerodynamics with Simcenter STAR-CCM+ This was very man-in-the-loop and we analyzed only a handful designs and Any way you look at it, the V-BAT isZach Hazen, aerodynamicist for thewere less sure of our optimum design, easily meeting the expectations ofV-BAT, swears by digital simulation. Ournotes Hazen. UAS users.customers want more payload, more fuel carrying capacity and longer flightFinding the optimum duct design Austin Howard, V-BATs chief engineer,time. High-fidelity simulation is a way toMartin UAV turned to Simcenter to do says, Where others are stuck adaptingstay ahead of their demands,, notesthis duct optimization. With Simcenter existing platforms, the V-BAT is designedHazen.STAR-CCM+, the firm conducted a full from scratch to be the safest, simplestcomputational fluid dynamics (CFD) and most tactical UAV in the Group 2/3Duct, duct, choose analysis of the duct performance in space.What makes the V-BAT work so well ishover and cruise conditions, including the unique ducted-fan tailsitterhover figure of merit and fixed-wing Simulation in the V-BAT design configurationthe heart and soul ofpropulsive efficiency. From the start, Martin UAV wanted tothe drone. Ducted fans include a build a true vertical takeoff and landingpropeller (fan) and a duct, bothHazen remembers the reason for (VTOL) system and not a hybrid. Hybridsconnected to the fuselage by struts.choosing Simcenter STAR-CCM+ spend a lot of electric power gettingBehind the rotating propeller lies asoftware: We invited a few companies airbornepower thats lost when itstator inside the duct and controlto validate our product at a known comes to payload carrying capacity. Asurfaces outside that act as an aileron, adesign point and landed with Simcenter true VTOL system design has complexrudder and elevators.STAR-CCM+ because it won the challenges, particularly designing for acompetition.We werent just looking at high thrust for hover while also reducingDucted fans are a boon for UAVthe quantitative answers, but also at drag for cruise. In simple terms, you areapplications. They can operate safely inhow their engineers listened and gave designing a helicopter and forward- closed confines and the environmentalanswers. We were extremely impressed flying aircraft in the same product,and noise footprint is minimal. Thewith the Simcenter support engineers.except the V-BAT cannot look like either.enclosed propeller blades act as a shield for noise and blade tip performanceIn particular, the blade element method Martin UAVs years of industrylosses. Takeoff and hover performance(BEM) capability let Martin UAV get a experience meant the first design wasare more efficient with a ducted fangood approximation at a low built from lower order tools, handbookconfiguration compared to open rotos.computational cost by approximating methods and experience. The idea wasIn horizontal flight, the ducted fanrotor performance characteristics. For simplebuild, test and fly. And itprovides stability as a horizontal tail.higher fidelity analysis of more worked, largely in-part due to the geniuspromising designs, the rigid body of the design. In fact, it worked so wellWith its many benefits critical to themotion (RBM) technology enabled the design was operation-test readysuccess of the V-BAT, it is no wonderanalysis with rotating propellers for for customers.that getting the V-BAT design rightobtaining detailed, more accurate meant getting the duct design right. Forperformance.Martin UAV had loftier goals to achieveMartin UAV, multiple objectives of the the best design possible and turned toduct complicated matters. To achieve Im buying a software with an array of Siemens Digital Industry Softwaresthe best possible efficiency in verticaltools to give either fast answers Simcenter simulation and test suitehover flight, the shrouded propellerscovering a lot of the design space with of solutions.needed a thick cross section to generateassumptions or perform high-fidelity 34'