The (in)compatibility of flying outdoors and indoors with the same MAV

The (in)compatibility of flying outdoors and indoors with the same MAV Rick Ruijsink

Contents Introduction Ruijsink Dynamic Engineering Operational criteria for outdoor flight Operational criteria for indoor flight Design criteria for outdoor flight Design criteria for indoor flight Solutions for combined tasks Conclusion

Introduction Ruijsink D.E. Delft University Aeronautical Engineering Propeller measurements for MAV s

Introduction Ruijsink D.E. Delft University Aeronautical Engineering Propeller measurements for MAV s Volvo Car, NL, Advanced Engineering

Introduction Ruijsink D.E. Delft University Aeronautical Engineering Propeller measurements for MAV s Volvo Car, NL, Advanced Engineering Industrial Aerodynamics and (Aero( Aero)acoustics

Introduction Ruijsink D.E. Delft University Aeronautical Engineering Propeller measurements for MAV s Volvo Car, NL, Advanced Engineering Industrial Aerodynamics and (Aero( Aero)acoustics Ruijsink Dynamic Engineering since 1994 Aeromodelling since 1958 Electric flight pioneer since 1973

Outdoor flight

Outdoor flight Flight speed is required to cover a good distance in reasonable time

Outdoor flight Flight speed is required to cover a good distance in reasonable time Flight speed is required to allow significant headwind

Outdoor flight Flight speed is required to cover a good distance in reasonable time Flight speed is required to allow significant headwind Gust tolerance is most important for both flight path stability and structural integrity

Indoor flight

Indoor flight Low flight speed is preferred to allow reasonable reaction times for both control and surveillance

Indoor flight Low flight speed is preferred to allow reasonable reaction times for both control and surveillance Manoeuvrability is the most important quality of an indoor MAV

Indoor flight Low flight speed is preferred to allow reasonable reaction times for both control and surveillance Manoeuvrability is the most important quality of an indoor MAV Turning radius is the first important aspect of manoeuvrability

Outdoor flight, gust sensitivity

Outdoor flight, gust sensitivity Angle of Incidence increment due to gust w α = w V [ rad]

Outdoor flight, gust sensitivity Angle of Incidence increment due to gust w α = w V [ rad] Lift increment due to gust w L = ½ ρ V S Cl 2 α w V [ N ]

Outdoor flight, gust sensitivity The gust induced acceleration is: a L m = M 2 sec

Outdoor flight, gust sensitivity The gust induced acceleration is: ½ ρ Cl a = α V M S w m sec 2 Slow flying > Low gust induced acceleration High wing loading a fundamental requirement for low sensitivity to gusts

Indoor flight, turning radius

Indoor flight, turning radius In a turning flight the equilibrium of forces is: L = Lift force α = Angle of bank Fh = Horizontal force (centrifugal) Fv = Vertical force (gravity)

Indoor flight, turning radius The three forces are: 1. L = ½ ρ V Cl 2 S [ N ] 2. Fh = L sin α = M V 2 R [ N ] 3. Fv = L cosα = M g [ N ]

Indoor flight, turning radius From the first and second equation: R = M S ½ 1 ρ Cl sinα [ m] Conclusion: The minimum turning radius is directly proportional to wing loading

Indoor flight, turning radius Example with Cl = 0.8 and sinα = 0.9: M R = 2.3 [ m] S

Indoor flight, turning radius Example with Cl = 0.8 and sinα = 0.9: M R = 2.3 [ m] S and Wing loading 1 kg/m 2 (10 gr/dm 2 ): [ ] R = 1 2.3 = 2.3 m

Indoor flight, turning radius The minimum turning radius is directly proportional to wing loading The minimum turning radius is essentially independent of the speed R = M S ½ 1 ρ Cl sinα [ m]

Indoor flight, turning radius Equation 3 is required to determine the minimum speed in the turn which is a function of the bank angle

Outdoor-Indoor incompatibility

Outdoor-Indoor incompatibility For outdoor flight we need a high wing loading

Outdoor-Indoor incompatibility For outdoor flight we need a high wing loading For indoor flight we need a light wing loading

Outdoor-Indoor incompatibility For outdoor flight we need a high wing loading For indoor flight we need a light wing loading These requirements are fundamentally incompatible in conventional designs

Outdoor-Indoor solutions

Outdoor-Indoor solutions 1. Compromise In some cases an MAV can be given just the right wing loading to complete both tasks satisfactory

Outdoor-Indoor solutions 1. Compromise In some cases an MAV can be given just the right wing loading to complete both tasks satisfactory 2. Radical When the requirements for both tasks are more stringent, a different solution is required The wing loading shall be adapted to each case

Out-Indoor, radical solution 1 Dropped mass

Out-Indoor, radical solution 1 Dropped mass After completing the outdoor task a part of the power source can be dropped before or just after entering the building

Out-Indoor, radical solution 1 Dropped mass After completing the outdoor task a part of the power source can be dropped before or just after entering the building This is a simple solution, can only be used when a return of the MAV to the base is not required

Out-Indoor, radical solution 2 Changed geometry

Out-Indoor, radical solution 2 Changed geometry When light wing loading is required the wing area could be increased Expanding wings have been shown before, either span wise or chord wise

Out-Indoor, radical solution 2 Changed geometry When light wing loading is required the wing area could be increased Expanding wings have been shown before, either span wise or chord wise A Rogallo type wing could be deployed inside the building that eventually could be detached at return

Conclusion Design of an MAV destined to fly both indoors and outdoors is a challenging task When both tasks need to be performed with authority a conventional fixed geometry, fixed mass MAV is not suitable

Thank you for your attention