Project 04 · Aerospace & UAVs

Aero Portfolio

Aircraft are where I first fell for engineering. This page collects the aerospace work I did as an undergraduate engineering student at Thapathali Campus in Nepal: a glass-fibre composite monocoque fuselage for a 3-metre wingspan RC aircraft, a Pixhawk-powered autonomous quadcopter, my final-year autonomous fixed-wing UAS for wildlife patrols, and the Boeing Aeromodelling Competition at IIT Bombay, first as a competitor in 2019 and then as a mentor in 2023.

Aircraft Design Composites Autonomous Flight Flight Stability Mission Planning XFLR5 Pixhawk Mission Planner CAD 3D Printing

Watch the 2023 flight video Jump to projects

Where

Thapathali Campus, IOE

Projects

4 aero builds

Largest airframe

3000 mm wingspan

Best result

4th · IIT Bombay 2023 (mentor)

The projects

Project	What it is	Key tools
Composite monocoque	Glass-fibre monocoque fuselage for a 3000 mm wingspan RC aircraft, made from a 3D-printed mold core	CAD · 3D printing · 250 GSM glass fibre
Autonomous quadcopter	Pixhawk quadcopter flying manual and GPS-based autonomous missions	Pixhawk · GPS · flight planning
Wildlife UAS	Final-year autonomous fixed-wing UAV for national-park patrol support, 20+ test flights	XFLR5 · Pixhawk · Mission Planner
Boeing Aeromodelling	IIT Bombay: top 20 as a competitor (2019), First Runner-up as a mentor with a 600 g payload (2023)	Aircraft design · fabrication

Glass-fibre composite monocoque body

A hollow, one-piece fuselage for a 3 m wingspan RC aircraft. I designed and fabricated it at Thapathali Campus, IOE, under the guidance of Lecturer Biman Rimal.

The goal was to fabricate a lightweight monocoque composite body for an RC model with a 3-metre wingspan. In a monocoque the skin itself carries the load, so there's no internal frame adding weight. We set out three objectives:

Mold design. Test what the mold has to get right for a glass-fibre part.
Manufacturing. Explore methods for building a glass-fibre RC aircraft.
Performance. Evaluate the strength, stiffness and weight of the finished part.

From surface to mold core

The fuselage started as a surface model built on a wireframe of cross-sections. Initial design sketches were developed alongside it, and the mold was visualised in CAD before the mold core, a positive of the fuselage, was sent for 3D printing.

CAD wireframe of fuselage cross-sections used to build the monocoque surface — **Fig. 1** — Fuselage surface built on a wireframe of cross-sections.

Concept CAD of the split mold with hand-written manufacturing notes — **Fig. 2** — Concept CAD of the mold, marked up with the manufacturing steps.

Mold core sections being 3D printed with support structures — **Fig. 3** — Printing the mold core in sections.

The assembled 3D-printed fuselage mold core — **Fig. 4** — The finished 3D-printed mold core.

Negative mold and layup

The printed core was used to pull a negative half mold, made from glass-fibre mat. That negative mold was then used to lay up the hollow monocoque itself in 250 GSM glass-fibre cloth. The demolded body comes out with the vertical stabiliser built in, plus mounts for the horizontal stabiliser and the wing.

Negative half mold being prepared from the 3D-printed core — **Fig. 5** — Preparing the negative half mold from the printed core.

Yellow glass-fibre monocoque fuselage taken out of the mold — **Fig. 6** — The monocoque out of the mold, with vertical stabiliser and HS and wing mounts.

The finished aircraft

The team standing behind the finished 3 m wingspan RC aircraft — **Fig. 7** — The team with the finished aircraft.

Painted blue monocoque fuselage standing between the two wing panels — **Fig. 8** — Painted fuselage with the two wing panels.

Person lying next to the RC aircraft on grass for scale — **Fig. 9** — For scale: a 3000 mm wingspan next to a person.

Wingspan	3000 mm
Body length	1200 mm
Body weight	2000 g
Skin	250 GSM glass-fibre cloth, hollow monocoque
Tooling	3D-printed mold core → glass-fibre-mat negative half molds

Autonomous quadcopter

A Pixhawk quadcopter that flies manual and GPS-based autonomous missions.

This quadcopter runs on a Pixhawk flight board and can fly both manually and autonomously from GPS waypoints. It uses the same flight board I used for autonomous flight in the fixed-wing UAV of my final-year project (below), so with that experience behind me I built a quadcopter with flight-planning capability. It flew its planned missions without a problem.

Quadcopter with Pixhawk flight board on a red and white frame — **Fig. 10** — The Pixhawk-powered quadcopter.

Quadcopter in flight above the planned mission path — **Fig. 11** — In flight, with the planned path and a normal take-off.

The project also got me looking past GPS: I learned about navigation in GPS-denied environments and explored other navigation techniques.

Outreach: the quadcopter was built for education. We used it for demonstrations to secondary-school students and presented it at an exhibition.

Final-year project — autonomous UAS for wildlife patrols

A locally built fixed-wing UAV to give national-park patrols cheap eyes in the sky.

The idea came from a visit to a national park, where we learned how important the imported drones that had been deployed there were to the security teams. Our final-year project set out to build a locally produced autonomous UAV that could give security personnel the same kind of aerial support on patrol, at much lower cost.

Design and stability in XFLR5

The conceptual design modelled the fixed-wing aircraft at real size, with the mass distributed through the body and the other model parameters defined. Using XFLR5, we confirmed both the static and dynamic stability of the aircraft. Only once stability was confirmed did the project move on to building and testing a prototype.

XFLR5 model of the fixed-wing UAV with mass distribution and model parameters — **Fig. 12** — Real-size XFLR5 model with mass distribution and model parameters.

XFLR5 polar plots for the aircraft — **Fig. 13** — XFLR5 polar plots.

XFLR5 time responses showing oscillations damping out — **Fig. 14** — Dynamic-stability time responses: the oscillations damp out.

Prototype, programming and flight testing

After building the prototype, we programmed the Pixhawk flight board and tested it for autonomous flight. Telemetry and GPS antennas on the aircraft handled data acquisition and navigation. Path planning was uploaded with Mission Planner, which gives a visual of the mission along with key flight data such as terrain altitude.

Fixed-wing UAS prototype on grass, with telemetry and GPS antennas — **Fig. 15** — The prototype, with its telemetry and GPS antennas.

Mission Planner screen with waypoints over satellite imagery — **Fig. 16** — The mission planned in Mission Planner.

Logged flight paths plotted over the waypoints — **Fig. 17** — Flight paths from the onboard log, plotted over the waypoints.

Real-time telemetry was recorded and then pulled from the onboard data logger. That let us analyse the flight path and judge how well the flight board carried out the mission it was given.

Outcome: this prototype became our test mule for more than 20 flights, and those flights gave us the data we needed to improve the mission planning and tune the flight board.

Boeing Aeromodelling Competition, IIT Bombay

2019 as a competitor, 2023 as a mentor.

2019 — competitor

The Boeing Aeromodelling Competition at IIT Bombay in 2019 was my first international event, and our team finished in the top 20. It taught me a great deal about aircraft design, flight dynamics and how aviation really works. It's also why I went on to take electives in aircraft structure design, aircraft dynamics and avionics, and it led directly to our final-year autonomous wildlife UAV.

Team preparing to hand-launch the aircraft at IIT Bombay, 2019 — **Fig. 18** — Getting ready to hand-launch, IIT Bombay 2019.

The 2019 aircraft in flight over the field — **Fig. 19** — Our aircraft in flight.

The 2019 team with their banner and aircraft — **Fig. 20** — The 2019 team.

2023 — mentor

After graduating, I got the chance to mentor aeromodelling on campus and supervised undergraduate students for the same competition in 2023. My team finished 4th, carrying a 600 g payload, and earned a lot of appreciation from the campus.

Build photos: body, wing, release mechanism, full model and servo connection — **Fig. 21** — The 2023 build: body, wing, release mechanism, full model and servo connection.

The 2023 team holding their aircraft at IIT Bombay — **Fig. 22** — The 2023 team at IIT Bombay.

What I took away

Prove stability before you build. On the wildlife UAS, nothing was cut until XFLR5 showed the aircraft was statically and dynamically stable.
Tooling is half the part. For the monocoque, the quality of the fuselage came down to the chain from CAD surface to printed core to negative mold.
Fly a mule, read the logs. Twenty-plus test flights and the onboard logs, not the plan on screen, are what tuned the flight board and improved our missions.
One flight stack, many airframes. The Pixhawk experience from the fixed-wing UAS carried straight over to the quadcopter.
Competitions compound. One competition in 2019 shaped my electives and my final-year project, and later let me mentor a team to First Runner-up.

Files & links

Flight video and where to find more.

🎥 Boeing Aeromodelling 2023 — flight video linkedin.com ▶️ My YouTube channel youtube.com 💼 LinkedIn profile linkedin.com/in/dhanpradhan