Powered Lift Wings for STOL Aircraft

Inter IIT Tech Meet 14 High Prep Problem Statement by LAT Aerospace

INTER IIT Tech meet 14.0

Inter-IIT Tech Meet is the annual pan-IIT technological competition where students from all 23 Indian Institutes of Technology (IITs) compete to solve complex, real-world problems. Established in 2012 as a student initiative at IIT Kanpur, it has evolved into a prestigious event officially approved by the IIT Council. The 14th Inter IIT tech meet was hosted by IIT Patna, we were a part of the contingent representing IIT Bombay. (Team photoshoot on left)

I had the privilege to lead a team of 20 undergraduate students (Along with co-leads Chaitanya and Aryaman) working on the high preparation class problem statement put forth by Gurugram based Company LAT Aerospace. We were tasked with the development of a mathematical model for Wing-Propeller Interaction and use the model to design a wing + thrust device configuration to meet certain performance requirements.

Math Model

Targets for the math model

Math model Architecture

THRUST DEVICE and WAKE MODEL

The rotor wake has been modelled using BEMT (for near blade), Landgrebe for contraction zone and khan model for entrainment and self similar regions. The wake model we have used is customizable for thrust device characterization. Furthermore, we assume that the propellers have stators attached to it, hence swirl velocity is minimal. Below is an illustration of different wake regions and a contour plot of axial velocity field plotted in r-z plane.

Illustration of wake zones

Axial velocity field contour plot for a sample thrust device

NON-UNIFORM WING MODEL

We use a modified lifting line theory based wing with some changes to incorporate non uniformity of geometry, inflow and aerodynamic properties.

All non uniformities considered spanwise

2D Aerodynamic properties as input

Lifting line theory based solvers aim to solve circulation distribution such that the lift due horse shoe lattices matches the integrated 2D lift considering downwash. Using conformal mapping and galerkin projection, we have a linear equation, solving which gives circulation distribution expressed in modal space.

Möbius Conformal mapping from y space to theta space

Nodal solution →

→ Modal solution

EFFECT OF FLAPS

They contribute to flow turning and modify 2D Aerodynamic properties. Our model considers both these aspects

INTEGRATION OF WING AND WAKE

We define a coordinate system wrt the wing and we specify the propeller placements. This allows us to superimpose the induced velocity fields to mimic the non uniform flow over the wing. Then the lifting line solver with the flow turning augmentations help compute downwash & circulation along with turning forces respectively