drongo design report

DronGo A submission to the Airbus Cargo Drone Challenge Presented by Local Motors In partnership with Airbus Group Sharang Kirloskar 22 May 2016

DronGo- A submission to the Airbus Cargo Drone Challenge May 2016

Sharang Kirloskar

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Love and gratitude to my brother, Samarth Kirloskar, for all his hard work and help with the graphics and representation of this design. The entire framework of preliminary aircraft design has been studied from: John D. Anderson, Jr, McGraw-Hill Book Company, "Introduction to Flight- Third Edition", 1989.


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Table of Contents

The Mission .............................................................................................................. 4 The Challenge .......................................................................................................... 4 The Design Drivers ................................................................................................... 4 Design ....................................................................................................................... 6

Inspiration ........................................................................................................... 6 3 View ................................................................................................................. 7 Layout ................................................................................................................. 7 Cargo Bay and Payload ...................................................................................... 8

Design Fundamentals ............................................................................................. 10 Weight ............................................................................................................... 10 Basic Design, Sizing, and Geometry ................................................................. 12 Selecting Aerodynamic Model ........................................................................... 12 Reynolds Number and Airfoil Selection ............................................................. 13 Thrust and Drag estimation ............................................................................... 15 Center of Gravity and Static Margin Discussion ................................................ 16 Designing the Control Surfaces ........................................................................ 18 Basic Structural Studies and Spar Sizing .......................................................... 18

Potential Equipment ................................................................................................ 20 Battery Scheme ................................................................................................ 20

Other Features ........................................................................................................ 21 Easy Handling and Transport ............................................................................ 21 Safety and Failsafe ........................................................................................... 22 Landing Gear .................................................................................................... 23 Capability in Mild Rain and Wind ...................................................................... 23

Performance ........................................................................................................... 24 Future Work ............................................................................................................ 24


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The Mission

To design an efficient fixed wing high speed cargo cruiser aircraft capable of VTOL and hover without tilting thrust/lift devices. This mission involves carrying a 5kg payload, executing a vertical takeoff, making a transition to cruise flight, cruising for 60km, making a transition back to hover, and then executing a vertical landing. Alternatively, a 3kg payload can be carried for 100km. The Challenge

To design the best possible airframe configuration within the envelope defined. The Design Drivers

This effort was undertaken in order to submit a valid entry to the Airbus Cargo Drone Challenge. The challenge calls for a multirotor/fixed wing hybrid aircraft to be used as a cargo delivery drone. This drone is to carry time critical medical supplies to traditionally hard to reach locations. DronGo is designed with speed, reliability, and efficiency in mind. The challenge brief and requirements summarized on the next page are the fundamental drivers of this design. DronGo is specially designed to need absolutely no multirotor assistance during the cruise flight. In Fixed Wing configuration, DronGo is passively stable and human controllable.


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Table 1: Summary of Requirements specified by the challenge

VTOL/Hover Configuration

Fixed Wing Configuration

General configuration Payload Operability Added

Features

• At least 4 lifting rotors

• At least 2 to 2.5 mins

of hover

• Recommended disc

loading between 10

kg/m^2 and 50

kg/m^2

• At least 1

pusher/tractor motor

• At least 1 fixed wing

• At least 80km/h.

• Not more than

194km/h

• Recommended wing

loading between 10

kg/m^2 and 30 kg/m^2

• No tilting of any rotors

• Only electric

• Fully loaded t/o weight

less than 25kg

• Max wing span 5m

• Max length 4m

• Max single part

dimension of modular

pre flight assembly is

2m

• All prescribed

electronics

accommodated

• All direct drive fixed

pitch props

• No more than 10

motors/rotors all in all

• access on lower side

• 3kg for 100km or 5 kg

for 60km

• Medical Cargo

• Sanitary cargo

• Must be a single bay

near CG

• Fixed and internal

cargo

• minimum:

450*350*200mm

• Easy accessibility

• Impossible to jettison

• smaller payload must

also fit

• Interchangeability of

cargo to sensor

payload

• Easy

• Safe

• Affordable

• off the shelf

rechargeable

batteries

• Up to 10m/s head

and cross wind

• Modular assembly

• recommend

parachute

• Low

Maintenance

• 20 min

turnaround

between flights

• swappable

batteries

• -30c to 50c

• moderate rain

• Easy to transport

• Transportable by

2 average people


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Design

Inspiration

Traditional fixed wing aircraft require a lot of space on the ground to operate safely. With long runways, and large hangars comes limited adaptability. Over the last few years, aviation enthusiasts from around the world watched a brand new flying machine come together. The Multirotor. A machine made possible by a remarkable interaction between electronics and aviation. A machine that can take off and land in about the space it occupies sitting still. A brilliant solution to the lack of runways or open spaces in large urban developments or underdeveloped regions. But wait, multirotors cannot cruise nearly as efficiently as fixed wing aircraft. So we can takeoff and land almost anywhere but don't have enough endurance to get around much. This design is a seamless integration of a multirotor system and a fixed wing aircraft. It is aimed at achieving the full efficiency of a high speed cargo cruiser aircraft while using a multirotor system to execute VTOL and sustain hover. DronGo's biggest advantage is that the Multirotor system causes negligible interference with the Fixed Wing system. This is because The Multirotor system is either concealed or is aft of all Fixed Wing aerodynamics. By this, DronGo is a unique design which offers true fixed wing efficiency integrated with a Multirotor. The aircraft uses a tricopter configuration for the multirotor system with two coaxial and counter rotating motors in the front. This makes it a 2-1-1 Y configuration. In the fixed wing configuration, the aircraft has one main wing, one canard, and two vertical stabilizers. DronGo's directional stability in fixed wing mode comes from two vertical tails that also function as the multirotor motor mounts and the landing gear. These kinds of multipurpose structures are used in several places in the design, making DronGo a well integrated product. With this combination DronGo is capable of delivering time critical cargo in traditionally hard to reach places much faster than traditional means can. Initial concepts allowed us to find the optimal wing span for our design. It was observed that a span larger than 3m would have high thrust requirements unless it was a very high aspect ratio wing. High aspect ratio wings were avoided because of the inherent roll instability and tip stalling characteristics. For this reason, the span was reduced till the ideal wing area, and thrust requirements were achieved with a medium aspect ratio. This brought us to the following wing: Span: 3m Area: 1.25m2 Aspect Ratio: 7.2


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3 View

Layout

Units in mm


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Cargo Bay and Payload


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The cargo bay is designed with automation in mind. Even though DronGo is apt for special missions, it can also be used as a routine delivery machine for less critical cargo. In cases where automation is desired, designs exist for a ground station with a conveyor belt ramp to place the cargo in the hold. In cases where smaller payload is to be carried, the cargo hold can easily be partitioned to prevent the cargo from moving inside. Cargo is not the only purpose that DronGo can solve. If surveillance or sensor equipment needs to be carried, DronGo is a very stable platform and will cause minimal interference with the sensor equipment. Traditional solutions involve an internal combustion engine which causes considerably more vibrations. If sensor equipment needs to be carried, the hydraulic shafts lowering the bay can easily be removed and the door can be hinged. Once the door is hinged, the user has the option of leaving it a few degrees cracked open allowing the extension of sensor equipment.

550*360*200 mm


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Design Fundamentals

Weight

The construction of the aircraft is primarily (>90%) Carbon Fiber Reinforced Polymer. The exceptions are the air data probe on the nose, the camera bubble, motors, hinges, and the assembly hardware. The internal components are mostly electronic components and have defined weights. In addition, we also know the loads experienced by our primary surfaces and can therefore size the primary load paths accordingly. Finally, we know the total volume of the carbon fiber used and, using the density of Carbon fiber (AS4) as 1.75g/cm3, can now conduct a mass buildup of the entire aircraft. The buildup shown on the next page is based on preliminary concepts and has been done conservatively. There is room for further thought on weight reducing optimizations. For best use of the aircraft weight, batteries with high specific energy are required. For this reason, DronGo is powered by Lithium Polymer batteries. Rechargeable Lithium Polymer batteries of the required specifications can be found at most hobby stores.


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Table 2: Mass Buildup. Note: All units in (kg).

Assembly Sub Assembly Mass Hardware Mass Left Wing Left Wing 0.4 Multirotor Motors w prop 3

Vertical Tail 0.2 Pusher Motor w prop 0.9

Motor Mount 0.1 Multirotor ESCs 0.45

Spar 0.3 Pusher ESC 0.12

Servos 1

Right Wing Right Wing 0.4 Air Data Probe 0.322

Vertical Tail 0.2 Transponder 0.115

Motor Mount 0.1 Flight Control Computer 0.58

Spar 0.3 Communication Systems 0.575

Camera 0.483

Aft Fuselage Fuselage skin 0.25 Batteries 5

Center Rib 0.25 Parachute 1.02

Jettison Door 0.15 Launcher 0.1806

Cargo Bay 0.2 IMU 0.0575

Cargo Bay Door 0.1 Air Data Systems 0.127

Motor Mount 0.2 Wing Spar 0.35 Hardware Total 13.93

Fwd Fuselage Fuselage skin 0.3

Center Rib 0.25

Multirotor Faring 0.2

Multirotor Motor Mount 0.15

Longitudinal Stiffners 0.2

Canard Spar 0.3

Canard 0.4 Structural Total 5.5 Hardware Total 13.93 Nose Landing Gear 0.2 Payload 5

Structural Total 5.5 All-Up Mass 24.43kg


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Basic Design, Sizing, and Geometry

Now that we have the mass, and suggested wing/disk loading, we can begin some initial sizing of the aircraft. For further conservatism, let us consider the worst case All-Up Mass to be 25kg.

𝑊𝑊 = 245.25𝑁𝑁

𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐷𝐷𝐿𝐿𝐿𝐿 𝑓𝑓𝐿𝐿𝑓𝑓 𝐿𝐿𝑑𝑑𝐷𝐷𝐷𝐷𝑓𝑓𝑑𝑑𝐿𝐿 𝑝𝑝𝑑𝑑𝑓𝑓𝑓𝑓𝐿𝐿𝑓𝑓𝑝𝑝𝐿𝐿𝐿𝐿𝑝𝑝𝑑𝑑 = 30 𝐷𝐷𝐿𝐿𝑝𝑝2

𝑊𝑊𝐷𝐷𝐿𝐿𝐿𝐿 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐷𝐷𝐿𝐿𝐿𝐿 𝑓𝑓𝐿𝐿𝑓𝑓 𝐿𝐿𝑑𝑑𝐷𝐷𝐷𝐷𝑓𝑓𝑑𝑑𝐿𝐿 𝑝𝑝𝑑𝑑𝑓𝑓𝑓𝑓𝐿𝐿𝑓𝑓𝑝𝑝𝐿𝐿𝐿𝐿𝑝𝑝𝑑𝑑 = 20 𝐷𝐷𝐿𝐿𝑝𝑝2

The above data leads us to 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐴𝐴𝑓𝑓𝑑𝑑𝐿𝐿 = 0.83 𝑝𝑝2 𝑊𝑊𝐷𝐷𝐿𝐿𝐿𝐿 𝐴𝐴𝑓𝑓𝑑𝑑𝐿𝐿 = 1.25 𝑝𝑝2

Which takes us further to 𝑇𝑇𝑓𝑓𝐷𝐷𝑝𝑝𝐿𝐿𝑝𝑝 𝑝𝑝𝐿𝐿𝐿𝐿𝑓𝑓𝐷𝐷𝐿𝐿𝑐𝑐𝑓𝑓𝐿𝐿𝑐𝑐𝐷𝐷𝐿𝐿𝐿𝐿 𝑃𝑃𝑓𝑓𝐿𝐿𝑝𝑝 𝐷𝐷𝐷𝐷𝐿𝐿 = 0.6𝑝𝑝

𝑄𝑄𝑐𝑐𝐿𝐿𝐿𝐿𝑝𝑝𝐿𝐿𝑝𝑝 𝑝𝑝𝐿𝐿𝐿𝐿𝑓𝑓𝐷𝐷𝐿𝐿𝑐𝑐𝑓𝑓𝐿𝐿𝑐𝑐𝐷𝐷𝐿𝐿𝐿𝐿 𝑃𝑃𝑓𝑓𝐿𝐿𝑝𝑝 𝐷𝐷𝐷𝐷𝐿𝐿 = 0.51𝑝𝑝

As this design essentially uses a tricopter for the VTOL and hover capabilities, the hover propeller diameter is set per tricopter requirements at 0.6m. All propellers on DronGo are fixed pitch direct drive propellers. Also, based on initial concepts, considering a span of 3m,

𝐹𝐹𝐷𝐷𝐹𝐹𝑑𝑑𝐿𝐿 𝑤𝑤𝐷𝐷𝐿𝐿𝐿𝐿 𝑝𝑝𝐿𝐿𝐿𝐿𝑓𝑓𝐷𝐷𝐿𝐿𝑐𝑐𝑓𝑓𝐿𝐿𝑐𝑐𝐷𝐷𝐿𝐿𝐿𝐿 𝐴𝐴𝐷𝐷𝑝𝑝𝑑𝑑𝑝𝑝𝑐𝑐 𝑅𝑅𝐿𝐿𝑐𝑐𝐷𝐷𝐿𝐿 = 7.2

Selecting Aerodynamic Model

Now to understand whether our aerodynamic model is to account for compressibility effects or not, we need to calculate the Mach Number. For 𝑀𝑀 > 0.3, compressibility would have to be accounted for. Assuming the ambient temperature range during missions,

𝑇𝑇 = −30 𝑐𝑐𝐿𝐿 50 𝐶𝐶 𝐿𝐿 we get the speed of sound in our envelope.

𝐿𝐿 = 313 𝑐𝑐𝐿𝐿 360 𝑝𝑝𝐷𝐷

Further assuming a cruise speed of,

𝑉𝑉∞ = 80 𝑐𝑐𝐿𝐿 194 𝐷𝐷𝑝𝑝ℎ𝑓𝑓

We can conclude the max Mach Number for our envelope.

𝑀𝑀 = 0.062 𝑐𝑐𝐿𝐿 0.17


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We can say that we do not need to account for any compressibility effects. Reynolds Number and Airfoil Selection

We can now proceed to calculate the Reynolds Number for our envelope. Assuming an altitude of 2000m MSL and ISA+20°C based on the design guidelines, density is estimated as

𝜌𝜌 = 0.954 𝐷𝐷𝐿𝐿𝑝𝑝3

Sutherland's formula was used to calculate the range for dynamic viscosity (µ).

µ = 1.5786 𝐸𝐸 − 5 𝑐𝑐𝐿𝐿 1.9821 𝐸𝐸 − 5 𝐷𝐷𝐿𝐿𝑝𝑝. 𝐷𝐷

If the main wing Aspect Ratio is 7.2 for desired flight characteristics, and the rest of the geometrical constraints are applied, the Mean Aerodynamic Chord is calculated as

𝑀𝑀𝐴𝐴𝐶𝐶 = 0.402 𝑝𝑝 And so, the envelope for Reynolds Number is

𝑅𝑅𝑑𝑑 = 700,000 𝑐𝑐𝐿𝐿 1 𝑀𝑀𝐷𝐷𝑀𝑀𝑀𝑀𝐷𝐷𝐿𝐿𝐿𝐿 In order to calculate the required CL-Cruise range, let's set Lift=Weight. As our mass is 25kg, our weight and lift is 245.25N.

𝐶𝐶𝐿𝐿−𝐶𝐶𝑓𝑓𝑐𝑐𝐷𝐷𝐷𝐷𝑑𝑑 = 0.401 With this progress, we can now begin airfoil selection. Airfoil Selection Criteria

• Optimal performance between Re 700,000 to Re 1 million • Minimum drag because of speed critical application • Delayed and docile stall • Predictable and linear lift curve slope • CL values at (L/D)max near 0.401.

Based on the above selection criteria, the airfoil chosen for the wing and canard is the NACA 2410.


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In order to use this data for our design, we needed to first apply a finite wing correction. This wing is of conventional configuration with moderate Aspect Ratio and Sweep, so assuming the Oswald's Efficiency to be 0.86, a finite wing correction can be made on the airfoil data. Here are some properties of the airfoil data after finite wing correction is applied.

Airfoil Property Finite Wing Corrected Value CDo 0.00541 CLo 0.161

CLmax 1.53 CD at CLmax 0.041

L/D max 98.47 CL at L/Dmax 0.6637 CD at L/Dmax 0.00674

As the L/Dmax is at Cl=0.66 and we only need CL-Cruise=0.4, we have some scope to reduce wing area and therefore weight too. Thrust and Drag estimation

Now that we have the wing, canard, and fuselage geometry, let's try to find the thrust required as a function of airspeed. For this, lets study our entire speed range from 80 to 194 kmph. Also let us consider our lift=weight for static equilibrium. We calculate our CL-required as a function of V∞ as

𝐶𝐶𝐿𝐿 =𝑊𝑊

12 𝜌𝜌𝑉𝑉2 ∗ 𝑤𝑤𝐷𝐷𝐿𝐿𝐿𝐿 𝐿𝐿𝑓𝑓𝑑𝑑𝐿𝐿

We calculate CD as a function of CL as

𝐶𝐶𝐷𝐷 = 𝐶𝐶𝐷𝐷,0 +𝐶𝐶𝐿𝐿2

𝜋𝜋. 𝑑𝑑.𝐴𝐴𝑅𝑅

In order to know what CD,0 value to use, a drag build up exercise was conducted. Based on aircraft geometry, surface finish of aerospace grade paint on CFRP, our estimate is

𝐶𝐶𝐷𝐷,0 = 0.029 We now have CL/CD as a function of V∞. Also remembering that thrust required is

𝑇𝑇ℎ𝑓𝑓𝑐𝑐𝐷𝐷𝑐𝑐𝑅𝑅𝑑𝑑𝑅𝑅 =𝑊𝑊𝐶𝐶𝐿𝐿𝐶𝐶𝐷𝐷


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we can now calculate ThrustReq as a function of (CL/CD) with W as a constant. We know (CL/CD) for the given speed, and we know the weight. And we can now represent the ThrustReq as a function of V∞. In the below image, you can see this relationship.

In this image, you will see that DronGo's thrust needs are minimum at the minimum of the speed range. This means, the slower we fly, while still being valid, the better. As the minimum speed permitted is 22m/s and we would like to account for a 10m/s head wind, we will consider our design cruise velocity to be 32m/s. Center of Gravity and Static Margin Discussion

DronGo has 2 major lifting surfaces. A main wing and a canard. Both have the same airfoil and both are rigged at the same incidence. By this, we can simplify the calculation of the Neutral Point. Due to these similarities, along with geometrical similarities between the main wing and the canard, we can assume that the lifting forces, caused by the wing and the canard, are proportional to their areas.

Newtons

m/s


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The Neutral Point is the point on the aircraft to which the aerodynamic forces can be resolved. By resolving the lifting forces, we can locate the Neutral Point. If NPC is the distance from the NP to the canard, and NPW is the distance from the NP to the wing, then

𝑁𝑁𝑃𝑃𝐶𝐶 . 𝑆𝑆𝑝𝑝 = 𝑁𝑁𝑃𝑃𝑊𝑊 . 𝑆𝑆𝑊𝑊 Also, based on our layout, we can fix the distance between the canard and the wing as

𝑁𝑁𝑃𝑃𝐶𝐶 + 𝑁𝑁𝑃𝑃𝑊𝑊 = 𝐶𝐶𝐿𝐿𝐿𝐿𝐷𝐷𝑐𝑐𝑤𝑤𝐷𝐷𝐿𝐿𝐿𝐿 −𝑝𝑝𝐿𝐿𝐿𝐿𝐿𝐿𝑓𝑓𝐿𝐿 Solving these two equations simultaneously, we can find NPC and NPW. However, this is not yet where we locate the CG. We still need to include a static margin to ensure that

𝛅𝛅𝑪𝑪𝑴𝑴𝛅𝛅𝜶𝜶

is negative. This will give the aircraft the ability to return to equilibrium when perturbed in pitch and give appropriate pilot feedback. Setting the static margin of 10% of the Main wing Root Chord, we can now calculate the location of the CG as

𝑊𝑊𝐷𝐷𝐿𝐿𝐿𝐿 𝑐𝑐𝐿𝐿 𝐶𝐶𝐶𝐶 = 0.322𝑝𝑝 After many iterations, and building a calculator, we have been able to keep the tricopter centroid, Aircraft CG, and Payload centroid within 40mm of each other. DronGo is very stable in all flight configurations.


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Designing the Control Surfaces

DronGo has an elevator on the Canard, and has two sets of ailerons on the wings. The inner ailerons can programmed as elevons by which they can be coupled with the elevator to assist with pitch control. Each vertical tail has a rudder for yaw control. Further studies regarding the roll, pitch, and yaw stability derivatives, and desired control authority are required. Optimizations and sensitivity studies need to be carried out before fixing the sizes of each control surface. However, the control surface sizing based on initial studies has been depicted below.

Basic Structural Studies and Spar Sizing


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In order to size the main spars for the wing and the canard, we first need to estimate the load acting on them. If we assume that the worst case load on the spars is during a 4g pull up, we can say that

𝐿𝐿𝑇𝑇𝐿𝐿𝑐𝑐𝐿𝐿𝑀𝑀 = 4 ∗ 𝑊𝑊𝑑𝑑𝐷𝐷𝐿𝐿ℎ𝑐𝑐 This means that the total lift would be LTotal = 981N. Once again, if the Canard and the Wing work in proportion to their areas,

𝑊𝑊𝐷𝐷𝐿𝐿𝐿𝐿 𝐿𝐿𝐷𝐷𝑓𝑓𝑐𝑐 = 704𝑁𝑁 𝐶𝐶𝐿𝐿𝐿𝐿𝐿𝐿𝑓𝑓𝐿𝐿 𝐿𝐿𝐷𝐷𝑓𝑓𝑐𝑐 = 277𝑁𝑁

Also, we know the lateral distance (Y) between the wing and canard aerodynamic centers. Assuming the lifting force is entirely resolved at the ACs of the wing and canard respectively, we can reduce this analysis to two different single cantilevered beam studies. One to size the canard spar, and one to size the wing spar.

𝑌𝑌𝐴𝐴𝐶𝐶𝑊𝑊𝐷𝐷𝐿𝐿𝐿𝐿 = 853𝑝𝑝𝑝𝑝 𝑌𝑌𝐴𝐴𝐶𝐶𝐶𝐶𝐿𝐿𝐿𝐿𝐿𝐿𝑓𝑓𝐿𝐿 = 617𝑝𝑝𝑝𝑝

Let's assume that both spars are cylindrical and have a wall thickness of 5mm. Also, lets assume the material is Carbon fiber (AS4) as before. By this we are able to make very rough estimates of the size as

𝐶𝐶𝐿𝐿𝐿𝐿𝐿𝐿𝑓𝑓𝐿𝐿 𝑆𝑆𝑝𝑝𝐿𝐿𝑓𝑓 𝐷𝐷𝐷𝐷𝐿𝐿𝑝𝑝𝑑𝑑𝑐𝑐𝑑𝑑𝑓𝑓 = 18𝑝𝑝𝑝𝑝 𝑊𝑊𝐷𝐷𝐿𝐿𝐿𝐿 𝑆𝑆𝑝𝑝𝐿𝐿𝑓𝑓 𝐷𝐷𝐷𝐷𝐿𝐿𝑝𝑝𝑑𝑑𝑐𝑐𝑑𝑑𝑓𝑓 = 30𝑝𝑝𝑝𝑝

The rest of the wing can be constructed in the traditional ribs and stringers way. The Fuselage is also constructed with CFRP. The center rib in the fuselage and the longitudinal stiffeners above and below the counter-rotating system are the primary load carriers in the fuselage. The wing spar stays in the aft fuselage section when disassembled and the wing halves slide onto it from both sides. In the below picture, the wing spar and the fuselage center rib are shown.


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Potential Equipment

Item Detail Notes Pusher Motor T-Motor MN4014 KV400 26A, 570.54W, 22.2V Pusher Propeller T-Motor 17x5.8CF 17" dia, 5.8" pitch, Carbon

Fiber Pusher ESC T-Motor T80A Multirotor Fwd Motors T-Motor U7 KV420 V2.0 48A, 1.2kW, 22.2V Multirotor Fwd Propellers T-Motor 18x6.1CF 18" dia, 6.1" pitch, Carbon

Fiber Multirotor Fwd ESCs T-Motor T80A Multirotor Aft Motors T-Motor U11 KV90 28.3A, 1.4kW, 48V Multirotor Aft Propellers T-Motor 28x9.2CF 28" dia, 9.2" pitch, Carbon

Fiber Multirotor Aft ESCs T-Motor FLAME80A Batteries ZIPPY Compact 5000mAh

6S 25C Lipo Pack 10 packs required. Each pack is 0.7kg.

Servos Hitec D-940TW 32-Bit, High Speed, Titanium Gear Servo

Waterproof, 12 servos required. Each servo is 0.068kg.

Battery Scheme

Based on the parameters are efficiencies entered in the frame sheet, DronGo's batteries would need to store 50,000 mAh at 25V in 5.3kg for the 100km mission or 36,000 mAh at 25V in 7.3kg for the 60km mission. The battery specified in the table above is capable of satisfying both these criteria. DronGo is designed to successfully execute both missions. Also, DronGo's battery bay is designed to house 16 of these batteries. At most 10 are required for the designed mission. So if the user wants to carry light sensor payload for long distances or long durations, the battery bay can house 6 extra batteries and payload weight can be sacrificed.


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Other Features

Easy Handling and Transport

This aircraft disassembles into only 7 modular pieces. No complicated on field assembly is required. The 7 pieces are easy to carry in the transport box. Along with this, the ground station required is minimal. The ground station antenna can be powered by a power source or by the battery in the van/truck. DronGo also has it's own IP and can be logged into remotely from anywhere in the world. As DronGo is fully autonomously controlled, it requires no human interaction once a mission execution has begun. This feature greatly adds to its compatibility with the Internet of Things. When disassembled, as shown in the picture below, there is no part with a dimension larger than 2m.


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When storage or shipping is necessary, DronGo can by disassembled and stored into a convenient box as shown below.

Safety and Failsafe

As DronGo is designed with safety in mind, the internal systems have redundancy and are designed conservatively. However, if ever, there is a catastrophic failure on board, an emergency parachute automatically activates and gently brings DronGo back down with minimal damage to it's landing location and to itself. DronGo does not need to turn any rotors on until it is actually time to take off. Within designed operation, there is no instance when the aircraft is on the ground and the rotors are on. The rotors might go through a spool up and spool down process before and after the flight but that should only take 1 or 2 seconds. As soon as DronGo's mission is initiated, the rotors spool up and the aircraft takes off. When DronGo is in cruise, the multirotor propellers are designed to lock. This is to prevent them from autorotating due to the incoming velocity. Autorotation is prevented to avoid unnecessary and unpredictable aerodynamic forces on the aircraft during fixed wing flight.


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Landing Gear

This design allows the vertical tails to themselves be the landing gear. By doing this, no unnecessary weight is added for landing equipment. For the nose gear, we have a very light and srong support that helps keep the craft horizontal during loading/unloading or during takeoff and landing. Also, this landing gear causes minimal interference with aerodynamics of the craft due to it's very thin design.

Capability in Mild Rain and Wind

In the design process, the cruise speed estimated is 32m/s. This means that DronGo is capable of maintaining 22m/s groundspeed even in head winds of up to 10m/s. On a good day, with no head winds, a standard mission should be completed with ample battery remaining or could be completed sooner. DronGo's only exposed electronics are the motors and the servos. As DronGo has 100% waterproof motors and servos, it is capable of maintaining performance even in mild rain. The materials used for the structural components are completely resistant to water and so ensuring that the hatch seals are regularly inspected will keep DronGo safe in mild rain.


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Performance

Range (Option Dependent) 32 to 53 NM (60 to 100 km) Cruise (Option Dependent) 43 to 81 knots (80 to 151 kmph) Useful Load (Option Dependent) 3 to 5 kg Max T/O mass 25kg Fuel All Electric Payload Bay Size 550*360*200 mm Future Work

This is only a preliminary analysis of the design. In order to proceed further, below is a list of a few of the things we will need to study:

• Lateral Stability and Vertical Tail Volume Coefficients. • Full structural analysis including placing and sizing of secondary and tertiary

structural members. • Overall design optimizations for weight. • Propulsion studies to decide exact propulsion requirements (prop pitch etc.) • Calculation of Roll, Pitch, and Yaw stiffness to size the control surfaces. • Understanding downwash effects of the canard on the main wing. • Optimizing wing, canard, and vertical tail sizes based on stability studies. • Calculation of stability derivatives to understand the effect of being perturbed

from steady flight. • Study the ability of the electronic equipment we are using to ensure full

optimization. • Study the roll, pitch, and yaw rates using the multirotor system based on the

aircraft mass and inertia distributions. • Battery performances, optimize the energy required calculations. • Possibly use a finite element method to study

structural details aerodynamic details model dynamics and vibration minimizing

UNLESS OTHERWISE SPECIFIED:DIMENSIONS ARE IN MILLIMETERSSURFACE FINISH:TOLERANCES: LINEAR: ANGULAR:

DEBUR AND BREAK SHARP EDGES

B

C

D

1 2

A

321 4

B

A

5 6

DRAWN

CHK'D

APPV'D

MFG

Q.A

FINISH:

NAME SIGNATURE DATE

MATERIAL:

DO NOT SCALE DRAWING REVISION

TITLE:

DWG NO.

SCALE:1:30 SHEET 1 OF 1

A4

C

WEIGHT: 25kg

DronGo 3 View

3000

2000

764

B

C

D

1 2

A

321 4

B

A

5 6

DRAWN

CHK'D

APPV'D

MFG

Q.A


FINISH: DEBUR AND BREAK SHARP EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A4

C

WEIGHT: 25kg

DronGo Front

3005

630

230

148

B

C

D

1 2

A

321 4

B

A

5 6

DRAWN

CHK'D

APPV'D

MFG

Q.A



NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A4

C

WEIGHT: 25kg

DronGo Left

300592



DronGo TopWEIGHT: 25kg

A4

SHEET 1 OF 1SCALE:1:20

DWG NO.

TITLE:

REVISIONDO NOT SCALE DRAWING

MATERIAL:

DATESIGNATURENAME

FINISH:

Q.A

MFG

APPV'D

CHK'D

DRAWN

3000

2000

500 350

100

100

190540



D

E

F

C

1 2 3 4

B

A

321 5

C

D

4 6 7 8

A

B

DronGo IsometricWEIGHT: 25kg

A3

SHEET 1 OF 1SCALE:1:8

DWG NO.

TITLE:

REVISIONDO NOT SCALE DRAWING

MATERIAL:

DATESIGNATURENAME

FINISH:

Q.A

MFG

APPV'D

CHK'D

DRAWN

Air Data Systems

Transponder

Flight Control Computer

Communication SystemsCamera

Emergency Parachute

Parachute Launcher

Batteries

IMU

Cargo Bay DoorCargo Bay

Air Data Probe

Camera

Air Data Systems

Transponder

Flight Control Computer

Co-axial Counter-rotation fans

Batteries

Parachute Launcher

Cargo Bay

Emergency Parachute

IMU

Air Data Probe

Communication Systems

Elevator

Aileron, or Elevon if Elevatorneeds assistance. Aileron

Rudder

1800

1200

1150

B

C

D

1 2

A

321 4

B

A

5 6

DRAWN

CHK'D

APPV'D

MFG

Q.A



NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A4

C

WEIGHT: 25kg

Stored Away

drongo design report

Documents