CDR Delivery Stream Presentation

Team Hailstorm

Mission Requirement

And

Interpretation

01

PDR Summary

Mission and requirements:

• Overview of mission requirement and payload constraints, for autonomous plane flight

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Aircraft configuration:

• High wing aircraft configuration for stable payload delivery
• Finalized a conventional tail with a 6 control surface layout

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Aerodynamics, and stability:

• NACA 4412 airfoil for the main wing and NACA 0012 airfoil for stabilizers
• XFLR5 data shows acceptable stability range utilizing airfoil configuration
• Primary feedback was more comparisons between different airfoils

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Sizing and performance:

• Established baseline aircraft size with overestimations to count for aerodynamic uncertainty
• Estimated stall speed, cruise speed, climbrate, and takeoff distance, with primary feedback of lowering mass and size

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Structural concepts:

• We identified major load paths and critical structural regions on the aircraft
• Plane concept utilizes lightweight structure to account for payload delivery mission

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Avionics and guidance:

• Utilize a flight controller, with GNSS navigation, and autonomous guidance system for hands free control

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Identified Stream

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Chosen Stream: Delivery Mission

Our aircraft is designed for the RC3 Delivery Stream. The mission objective is to carry the required 8 oz water bottle payload, complete a safe takeoff with the payload onboard, navigate toward the designated landing zone, and land as close as possible to the center of the LZ.

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The aircraft satisfies the core delivery requirements by using a fixed-wing configuration, maintaining a projected MTOW of 1.900 kg, remaining below the 5.000 kg rulebook mass limit, along with having 4 control surfaces.

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Low-Level Computer Vision

The aircraft will use a hybrid control strategy. Takeoff will be performed manually using the TX16S transmitter and ELRS receiver. Once airborne and stable, control may be transitioned to an ArduPilot-based flight controller using GPS/GNSS waypoint navigation to guide the aircraft toward the delivery landing zone. The baseline plan is to return to manual control for final approach and landing, with autonomous landing attempted only if permitted, tested, and approved.

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Discussion on Design Philosophy

The design philosophy is centered around building a stable, and lightweight payload-delivery aircraft that can handle autonomous flight rather than maximizing speed. Since the Delivery mission rewards accurate landing with the payload, the aircraft prioritizes controllability, predictable low-speed handling, and structural reliability.

Key design choices:

• High-wing configuration: improves passive roll stability and makes the aircraft easier to fly during takeoff, approach, and landing.
• Conventional tail layout: provides simple and predictable pitch/yaw stability with easy manufacturing and maintenance.
• Low wing loading: the current design uses a 1.50 m wingspan, 0.321 m² wing area, and approximately 58.0 N/m² wing loading, supporting slower, more manageable approach speeds.
• Payload near CG: the water bottle is positioned close to the aircraft CG to reduce trim change between minimum operating weight and MTOW.
• Simple truss-style fuselage: reduces mass while giving clear load paths between the wing, landing gear, payload bay, and tail.
• Modular avionics and payload layout: allows easier inspection, assembly, repair, and future adjustment before flight testing.

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Weight

Of

The

Design

02

MTOW and Minimum Operating Weight

Detailed Mass Breakdown

Detailed Mass Breakdown Cont’d

Detailed Mass Breakdown Cont’d

General

Arrangement

Of

Aircraft

03

Airfoil Selection

• After feedback from the PDR, various changes were made regarding airfoil selection
• The required airfoil for the main wing must be capable of providing low-speed lift, efficiency, and manufacturability
• NACA and non-NACA airfoils were examined through XFLR5

• NACA 0012 were kept as the airfoil for horizontal and vertical stabilizers

Main Wing Configuration

Main Wing Configuration Cont’d

Control Surface Sizing

Wing CAD

Horizontal Tail CAD

Vertical Tail CAD

Tail Holder CAD

Landing Gear CAD

Full Assembly CAD

Vertical Stabilizer Jig

Horizontal Stabilizer Jig

Main Wing Jig

Delivery: Payload Mounting and Location

The payload is mounted in a removable top-loading cradle located close to the aircraft CG. The mount uses a symmetric two-piece cradle to distribute the payload weight evenly about the fuselage centerline and prevent lateral shifting. This placement minimizes CG movement between unloaded and loaded configurations, improving stability, trim consistency, and controllability during takeoff, flight, and landing.

3 View Drawing

Avionics Schematic

3 View Schematic

Avionics Wiring Scheme

• The 3S LiPo battery is the main power source for the aircraft.
• The battery positive wire first passes through an external safety plug, allowing the aircraft to be safely disabled before handling.
• After the safety plug, power splits to the 40A ESC for motor power and to the Matek F405 flight controller for system monitoring/control.
• The ESC drives the brushless motor and receives throttle commands from the flight controller through S1.
• The TX16S transmitter communicates wirelessly with the HappyModel EP2 receiver, which sends pilot commands to the flight controller.
• The GPS/GNSS module sends position and heading data to the flight controller for assisted/autonomous navigation.
• The four FT9G servos connect to outputs S2–S5 and control the aircraft’s control surfaces.
• All components share a common ground so the system has one electrical reference.

Safety plug on the top in between nose and fuselage

Structural Integrity

04

Max Load Factor

Interfacing Between Parts & Components

The wing structure uses repeated rib sections with lightening holes to reduce mass while maintaining the required airfoil shape and internal stiffness. A long carbon fiber tube or wooden dowel passes through aligned holes in the wing ribs, acting as the main spanwise support member.

This tube/dowel interface helps transfer bending loads across the wing and keeps the ribs properly aligned during assembly. Carbon fiber is preferred for stiffness and low weight, while a hardwood dowel may be used as a simpler manufacturing option if sized appropriately.

Wing / Spar Interface

Interfacing Between Parts & Components

The tail assembly and vertical stabilizer are designed as a modular rear structure that attaches directly to the rear fuselage using screw fasteners and 2 wooden rods running along the bottom of the fuselage. The vertical stabilizer, horizontal tail, and rear mounting plates are aligned through the CAD geometry so that the tail surfaces remain square to the fuselage centerline during assembly.

The tail section is intended to be modular, allowing easier inspection, replacement, and adjustment before flight testing. Screws are used at the fuselage mounting points, with reinforced mounting plates/doublers to spread the load into the fuselage side structure.

Tail + Vertical Stabilizer Interface

Maneuver Load Envelope Diagram

Purpose

The maneuver load envelope defines the safe operating region of the aircraft by relating airspeed to load factor. It shows the speed range where the aircraft will stall before exceeding structural limits, and the speed range where excessive maneuvering could overload the structure.

Design Assumptions

• Aircraft MTOW: 1.900 kg
• Wing loading: 58.046 N/m²
• Air density: 1.225 kg/m³
• Positive limit load factor: +4.0g
• Negative limit load factor: -2.0g
• Structural safety factor: 1.5
• Ultimate positive load factor: +6.0g
• Estimated positive CLmax: 1.20
• Estimated negative CLmax​: 0.80

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Maneuver Load Envelope Diagram Cont.

The preliminary V-n diagram confirms that the aircraft has a defined safe maneuvering envelope for the Delivery mission. The aircraft should be operated below the selected dive speed of 22.2 m/s, with aggressive maneuvering avoided above the positive maneuvering speed of 17.8 m/s. The envelope is based on conservative structural load factors and will be refined after airfoil CLmax, final mass, and flight-test data are confirmed.

Structural Analysis

Balance, Stability, and Airworthiness of Design

05

Constraint Analysis

Chosen Design Region

Performance Estimates

Aircraft Pitch Stability

Aircraft Directional Stability

Elevator Trim Requirements: +/- 5°

• Cm VS. α graph illustrates Cm=0 within the interval of [-5°, 5°]
• α = -2.47°, which is slightly above the cruising AOA of -2.87°, implying proficient cruise operation within +/-5° elevator deflection
• Cruise AOA is found via eigen value plots, which are shown later

0°

+5°

-5°

α = -2.47°

Aileron Authority

0°

+5°

-5°

+15°

-15°

Rudder Authority

0°

-5°

+5°

CGX Values And Tail Arm Values

Longitudinal Dynamic Stability

Lateral Dynamic Stability

Dynamic Stability Notes

Delivery Time Estimate

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t_delivery ≈ t_TO + t_climb + t_approach + d_LZ / V_CRUISE

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V_Stall = 8.23 m/s

V_CRUISE= 13.0 m/s

ROC = 3.05 m/s

Runway distance = 10.7 m

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Takeoff:

V_LOF = 1.1V_Stall to 1.2V_Stall= 9.05 to 9.88 m/s

t_TO = 2(takeoff distance) / V_LOF ≈ 2.2 to 2.4 s

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Climb:

Assume climb altitude = 6 to 9 m

t_climb = h / ROC ≈ 2.0 to 3.0 s

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Approach:

V_app = 1.2VS to 1.3VS = 9.88 to 10.70 m/s

Assume final approach distance = 30 to 45 m

t_approach ≈ 2.8 to 4.6 s

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Total:

t_delivery ≈ (7 to 10 s) + dLZ / 13.0

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where dLZ is the unknown distance to the landing zone in metres.

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Summary of any Stability Augmentation

• The aircraft is designed to be passively stable without relying on electronic stabilization. The high-wing layout, conventional tail, and CG placement provide the primary stability of the aircraft. Based on the current CG table, the aircraft maintains a static margin of 10.3% at MTOW and 10.7% without payload, both within the selected CG envelope between the 20% forward limit and 5% aft limit.
• The payload is positioned close to the CG to minimize trim changes between the loaded and unloaded configurations. This helps the aircraft maintain similar handling qualities during both minimum operating weight and full delivery configuration.

Logistics

Of

The

Design

06

BOM

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Structural Material

BOM

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Fasteners and Adhesives

BOM

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Avionics and Powertrain

Scoring Analysis

Delivery Scoring Strategy

The aircraft is designed for the Delivery Stream, where scoring depends on successfully transporting the required payload to the landing zone and landing as close as possible to the target center. The rule set states that the Delivery score is based on proximity to the center of the LZ and total delivery time from takeoff to touchdown, with onboard guidance systems providing a score multiplier when used successfully.

Main Scoring Priorities

Successful mission completion first

• Aircraft must take off safely with the payload onboard.
• Aircraft must remain controllable and structurally intact.
• Payload must arrive at the landing zone.

Landing accuracy

• Score depends strongly on distance from the center of the target.
• Design prioritizes slow, stable approach speeds instead of maximum speed.
• Payload is placed near the CG to avoid trim changes during landing.

Autonomous / assisted guidance multiplier

• Baseline plan: manual takeoff, ArduPilot waypoint navigation, manual landing.
• Stretch goal: autonomous or computer-vision-assisted final approach if allowed and tested.
• A successful autonomous mission within the required time receives a higher multiplier.

Time management

• Aircraft should follow a direct and stable route to the landing zone.
• Excessive speed is avoided because landing accuracy is more important than minimizing time alone.
• The design targets a controlled approach rather than a fast, high-risk landing.