Colorado Mountains

In March 2019, I had the opportunity through my job to fly in the mountains of Colorado on a DHC-6 Twin Otter. Here are some images of the flight campaign.

[Book Review] Roskam’s Airplane War Stories

Dr. Jan Roskam’s Airplane War Stories is a seriously good book. The lessons come in bite sized tales (“War Story #”) with the wonderful treat of providing the moral (“Lesson”) in his own words.

This book won’t teach you how to analyze aircraft -Dr. Roskam’s other books take that charge- but once you do know the mathematics, the concept, and the application, this book is a lot of fun to read.

The first part of the book is a bit better than the later part. It is slightly disappointing that the book does not cover as many aircraft design topics with specific discussions of the aircraft features.

Thank you Dr. Roskam for this and other books. The book is available through several sources:

Recommended.

TuskaUAV talk on Aerodynamics and Propulsion

As the advisor of the TuskaUAV group, I was asked to give a 30 minute chat to the student group on the topic of aerodynamics and propulsion with a special emphasis on small unmanned aerial vehicles. The four-up double sided handout is available below. The formal talk concluded with a Q/A session both during and after the meeting. Thanks for the opportunity!

Blood Moon

20 Jan 2019, 11:20 CST.

[Book Review] Partial Differential Equations for Scientists and Engineers by Stanley J Farlow

Stanley Farlow’s textbook Partial Differential Equations for Scientists and Engineers is a reasonable introductory book for undergraduate and graduate students in the sciences and engineering. This book covers classical solution techniques, basic numerical methods, and -finally- the use of special techniques for solving non-trivial problems. This book is NOT acceptable for graduate students in mathematics, as can be seen directly in the title. Theory is briefly discussed, but the heart of the book is solving problems.

I taught a graduate course (GES 554, see here) for engineers with the book. ISBN-13: 978-0486676203

Pros:

  • Reasonable coverage of classical methods
  • Very low cost ($12).
  • Discusses the physics of why terms appear in PDEs

Cons:

  • Basic at best.
  • No formal mathematical proofs.
  • Only 1 section (Burger’s equ) discussing non-linear PDEs
  • Solutions in the back are often not correct
  • Topic order (especially for classification) is scattered.

Gulfstream GV / G550 CAD Model

Today, I created a CATIA CAD model of the Gulfstream GV / G550 aircraft. There are a few discrepancies in the details, especially with the windows and doors; however, the basic aircraft geometry is lofted from drawings.

Sharp aerospace engineers may question several of the fundamental design parameters and wonder about the airfoil selection (yes, supercritical, but GIII airfoils), surface quality (certainly not production quality), and purpose. It’s definitely not trivial to reverse engineer a CAD model from scratch, but it is doable for low to medium fidelity requirements. The CAD model is available here: https://grabcad.com/library/gulfstream-gv-g550-low-fidelity-2

Aircraft ECS for HVAC Students

On 11 Oct 2018, I was asked to provide an Aircraft Environmental Control System (ECS) primer for Mechanical Engineering HVAC students.

The lecture notes are available at: ECS-Aircraft

 

Articulated 4 Bar Mount Design

In this note, I will design an articulated 4 bar mount for a radar system using CATIA. The system needs to be designed and built rapidly for a VIP demonstration. Here’s the design:

First, the design requirements and needs:

  • Precise pointing requirements from nadir (straight down) to horizontal.
  • Mount on a boom lift / cherry-picker bucket
  • Separate two antennas of 30 pounds and 10 pounds by at least 2 meters with less than 1 deg of twist.
  • Designed, sourced, and built within a tight schedule

The articulated arm as designed by CATIA met the design goals with a commonly available actuator. The use of a CAD model allowed for tuning of the geometry and resulting kinematics.

Using the gearing ratio between the actuator and the output angle, conservation of power, and the measured actuator dynamics, I was able to analyze, simulate, and tune the dynamic/transient dynamics of motion of the system. This analysis allowed for a truly coupled actuator/mechanism design and ensured that my design remained feasible across the entire operational envelope.

Design drawings were created to construct the actuation arm.

The as-constructed articulated arm met the design requirements and when mounted on a boom-lift was successfully was used for a data collection experiment.

This articulated arm mechanism’s development shows the power of CAD with CATIA for rapid support of R&D projects. I was pleased.

Aerospace Structures Course

Aerospace Structures (AEM 341) is a core aerospace engineering course for the study of methods of analyzing advanced beam and stressed skin structures typical of aerospace vehicles. Dr. O’Neill taught this course in the Spring of 2018.Book: Introduction to Aerospace Structural Analysis, Allen & Haisler, Wiley. ISBN 0-471-88839-7 (Book Review)

Goals: By the end of the course, students should be able to:

  • Understand structural terminology, nomenclature, and aerospace structural elements.
  • Demonstrate basic static and accelerated loads concepts and estimates.
  • Determine principle stresses and principle directions
  • Demonstrate structural analysis of advanced beams and cells in bending and torsion
  • Demonstrate analysis of shear and shear flow
  • Analyze, design and test an aerospace structure as a term project
  • Fluently converse with loads and stress teams in a design setting

Example Lectures:

Course Evaluation: The student course evaluation is at: 18-AEM341-AerospaceStructures. I appreciate the kind words.

  • His notes are extremely clear, and he very effectively communicates the material. He’s far more concerned about us understanding the material than anything else.
  • Helped me regain my hope and enthusiasm for aerospace

XOR Checksum

Recently, I have been working with embedded systems for UAS applications. One of the systems requires commands be validated with an XOR checksum. Rather than doing this by hand, I made a small simple Windows app (download here).Nothing fancy.