Hi all,
I've moved to a new site, which will provide better information and support for aerodynamicists.
Better is better. Check it out here: www.doughunsaker.com.
The new site has free design and optimization software as well as demos that walk you through the basics for using the software.
Nothing like good software for good engineers! Try it out and leave some feedback.
Happy designing!
-Doug
Monday, January 5, 2015
Friday, July 4, 2014
Welcome
This site is intended to be a resource for anyone interested in aircraft design. Whether you're a UAV developer, RC hobbyist, student, or come from a big aerospace company, I hope this site has something to offer you.
This blog is a work-in-progress, so if there's a tool or site you'd like to see listed here that isn't, please leave me a note!
This blog is a work-in-progress, so if there's a tool or site you'd like to see listed here that isn't, please leave me a note!
Saturday, June 15, 2013
Landing Your Dream Job, Part 2: What Do You Think About?
In order to be happy in your career, it's imperative to answer this question honestly: "What do I think about?"
I heard a story once of a father who tutored his son in chemistry. The father was a well-known scientist and professor at the local university and thoroughly enjoyed tutoring his son. One day they sat down to go over one of the son's homework problems and the father exclaimed, "This is the exact same problem that you had last week! Hasn't your mind been working on this problem all week!?" "No," said the son, "I haven't thought about it at all since then." The father put down his pencil and sat back in his chair. "Son, if this isn't what you think about all week, then you might be in the wrong major. Go find a subject that gets you so excited, you can't sleep until you conquer it." The son went on to get a business degree and became an influencial business professor.
The father was right. If you're not engaged in a subject that excites you, you've got a long, boring career ahead of you. Not only that, you likely will not be competitive at what you do. Imagine trying to compete in cut-throat classes in medical school against students who have dreamed of being a doctor, have a passion for the medical field, and who lie awake at night trying to find a cure for cancer. It's difficult to pass a class that's graded on the curve filled with students like that. On the other hand, if your thing is math and there's nothing you enjoy more than proofs, then go do it! Go find what you love. If you're doing what you love, you'll excel and become a leader in your field.
Too often we feel limited by what our peers are doing with their lives, or what our family reputation is, or perhaps we feel an obligation to carry on the family business. Life is too long to spend it at an 8-to-5 job that doesn't stimulate you, and too short to waste time thinking that you can change occupations later.
My professor once made a statement to me that left an unforgettable impression: "People always say, 'On your deathbed, you won't be wishing you could have spent another day in the office.' Well," he said, "that's assuming they had a terrible job! I will definitely wish I could have spent one more day in my office." This is a man who is past retirement age and who gets up at 2:00 AM daily to work on research he loves. This is a man who found his passion and is incredible at what he does. Now I'm not suggesting that we should all want to spend our lives in the office - there's much more to life than that. I am suggesting, however, that the time we spend in the office can be enjoyable if we choose the right office.
So, what do you think about? It's worth giving that some thought. Just pay attention to where your mind goes when it has nothing to think about. What do you fantasize about? What would get you up in the morning before your alarm? If you can find it, you'll be unstoppable.
I heard a story once of a father who tutored his son in chemistry. The father was a well-known scientist and professor at the local university and thoroughly enjoyed tutoring his son. One day they sat down to go over one of the son's homework problems and the father exclaimed, "This is the exact same problem that you had last week! Hasn't your mind been working on this problem all week!?" "No," said the son, "I haven't thought about it at all since then." The father put down his pencil and sat back in his chair. "Son, if this isn't what you think about all week, then you might be in the wrong major. Go find a subject that gets you so excited, you can't sleep until you conquer it." The son went on to get a business degree and became an influencial business professor.
The father was right. If you're not engaged in a subject that excites you, you've got a long, boring career ahead of you. Not only that, you likely will not be competitive at what you do. Imagine trying to compete in cut-throat classes in medical school against students who have dreamed of being a doctor, have a passion for the medical field, and who lie awake at night trying to find a cure for cancer. It's difficult to pass a class that's graded on the curve filled with students like that. On the other hand, if your thing is math and there's nothing you enjoy more than proofs, then go do it! Go find what you love. If you're doing what you love, you'll excel and become a leader in your field.
Too often we feel limited by what our peers are doing with their lives, or what our family reputation is, or perhaps we feel an obligation to carry on the family business. Life is too long to spend it at an 8-to-5 job that doesn't stimulate you, and too short to waste time thinking that you can change occupations later.
My professor once made a statement to me that left an unforgettable impression: "People always say, 'On your deathbed, you won't be wishing you could have spent another day in the office.' Well," he said, "that's assuming they had a terrible job! I will definitely wish I could have spent one more day in my office." This is a man who is past retirement age and who gets up at 2:00 AM daily to work on research he loves. This is a man who found his passion and is incredible at what he does. Now I'm not suggesting that we should all want to spend our lives in the office - there's much more to life than that. I am suggesting, however, that the time we spend in the office can be enjoyable if we choose the right office.
So, what do you think about? It's worth giving that some thought. Just pay attention to where your mind goes when it has nothing to think about. What do you fantasize about? What would get you up in the morning before your alarm? If you can find it, you'll be unstoppable.
Landing Your Dream Job, Part 1: Introduction
I climbed aboard my return flight from an interview with a company I had followed for years. They were a good company working on interesting things and I was pretty sure I'd receive an offer from them. I found my seat and enjoyed the green, mountainous view as we lifted off. I could definitely get used to living here, I thought. There is plenty to do by way of out-of-doors in this area!
Still, I wasn't completely satisfied. When I was downright honest with myself, I still wanted to work for that little "cowboy" company in the middle of the desert. That's where the fun is, I thought.That's where I'd be doing cool stuff! The interview here in the fairy land had gone well, but I felt a little unsure about the type of work they would be asking me to do. It sounded like a lot of paperwork and documentation - not what I had hoped for as a first step into industry after years of education. If I could have landed a job with the desert company, I know they'd have me involved with design, build, and testing. That's the fun stuff. If only I could have landed a position with them. They didn't even read my resume! I was sure of it. I had applied cold turkey with a carefully designed resume to that company three months earlier, and received a form rejection letter in the mail stating that they were not interested. Not even a phone call! Well if they don't want me, I don't want them. That was the best consolation I could give myself.
I stared out the window in frustration. Not at myself, but at the system. Why do I feel like I have to obey the job-seeking system and take status quo? Why can't I find the job I want and become what I want to become?
Then, a crazy idea.
I decided to write a letter directly to the CEO of that little cowboy company. I'd never met him and he wouldn't know me from Adam, but what did I have to lose?What could he say? No? His staff already had. But at least I would have made it clear that I was serious about working there. I was serious about being an "A" player. I began to draft a letter on some scratch paper, "Dear Mr. _________, ..."
Although I never sent that letter, today I work for that little cowboy company in the desert -- and I'm working on one of the coolest projects I've ever heard of. I learned a lot through the application and interview process, and I'd like to share some tips I picked up along the way. Although my experiences are with the engineering field, these principles can be applied to any occupation. Most importantly, my journey taught me that landing your dream job is possible if you're willing to take some risks and pay the price.
Still, I wasn't completely satisfied. When I was downright honest with myself, I still wanted to work for that little "cowboy" company in the middle of the desert. That's where the fun is, I thought.That's where I'd be doing cool stuff! The interview here in the fairy land had gone well, but I felt a little unsure about the type of work they would be asking me to do. It sounded like a lot of paperwork and documentation - not what I had hoped for as a first step into industry after years of education. If I could have landed a job with the desert company, I know they'd have me involved with design, build, and testing. That's the fun stuff. If only I could have landed a position with them. They didn't even read my resume! I was sure of it. I had applied cold turkey with a carefully designed resume to that company three months earlier, and received a form rejection letter in the mail stating that they were not interested. Not even a phone call! Well if they don't want me, I don't want them. That was the best consolation I could give myself.
I stared out the window in frustration. Not at myself, but at the system. Why do I feel like I have to obey the job-seeking system and take status quo? Why can't I find the job I want and become what I want to become?
Then, a crazy idea.
I decided to write a letter directly to the CEO of that little cowboy company. I'd never met him and he wouldn't know me from Adam, but what did I have to lose?What could he say? No? His staff already had. But at least I would have made it clear that I was serious about working there. I was serious about being an "A" player. I began to draft a letter on some scratch paper, "Dear Mr. _________, ..."
Although I never sent that letter, today I work for that little cowboy company in the desert -- and I'm working on one of the coolest projects I've ever heard of. I learned a lot through the application and interview process, and I'd like to share some tips I picked up along the way. Although my experiences are with the engineering field, these principles can be applied to any occupation. Most importantly, my journey taught me that landing your dream job is possible if you're willing to take some risks and pay the price.
Friday, May 31, 2013
CFD Codes
Autodesk Simulation
ANSYS CFX
ANSYS Fluent
Caedium
Cart3D (NASA) (Desktop Aeronautics)
CFDExpert
CFL3D (Free to US Citizens)
Cradle
Dolfyn (Free)
elsA
FloEFD
FLOW-3D
FUN3D (Free to US Citizens)
OpenFOAM (Free)
OverFlow (NASA)
Star CCM+
SU2 (Free)
Technalysis
Xflow
Forums
CFD-OnlineSaturday, May 25, 2013
Aircraft Design Myth: A static margin of 5% will give good handling qualities
A 5% static margin is a rule of thumb followed by most aircraft designers. True, it's pretty decent for many airplanes. However, handling qualities have been shown to depend on the dynamic margin, not the static margin. To understand this, let's first look at the definition of the static margin.
The static margin is a function of the pitch stability of the aircraft and is defined as sigma = -Cm,alpha/CL,alpha. If the aircraft is stable in pitch, it will resist any distrubance in pitch and therefore naturally return to neutral. However, humans (and computers in the case of UAVs) are quite capable of controlling unstable motions. For example, walking and biking are unstable activities we do every day quite naturally. Therefore, although it is nice for a pilot to have an aircraft that is stable in pitch, it is not necessary. In fact, Perkins [1] suggests that many of the early successful airplanes, including the Wright flyer, were most likely unstable in pitch.
The dynamic margin, on the other hand, is a function of both pitch stability as well as pitch damping. The pitch damping opposes any sudden change in pitch. Therefore, if an aircraft's pitch damping is large enough compared to its pitch stability, we as humans are perfectly capable of controlling the aircraft. The dynamic margin can be directly related to pilot opinion, and hence, handling qualities. This means that there are known bounds for the dynamic margin that will result in level 1 handling qualities. For an excellent paper on the subject, see Phillips [2].
It is always wise to design the aircraft for an appropriate dynamic margin rather than the static margin rule of thumb.
[2] Phillips, W. F., and Niewoehner, R. J., "Characteristic Length and Dynamic Time Scale Associated with Aicraft Pitching Motion, " Journal of Aircraft, Vol. 46, No. 2, pp. 572-582.
The static margin is a function of the pitch stability of the aircraft and is defined as sigma = -Cm,alpha/CL,alpha. If the aircraft is stable in pitch, it will resist any distrubance in pitch and therefore naturally return to neutral. However, humans (and computers in the case of UAVs) are quite capable of controlling unstable motions. For example, walking and biking are unstable activities we do every day quite naturally. Therefore, although it is nice for a pilot to have an aircraft that is stable in pitch, it is not necessary. In fact, Perkins [1] suggests that many of the early successful airplanes, including the Wright flyer, were most likely unstable in pitch.
The dynamic margin, on the other hand, is a function of both pitch stability as well as pitch damping. The pitch damping opposes any sudden change in pitch. Therefore, if an aircraft's pitch damping is large enough compared to its pitch stability, we as humans are perfectly capable of controlling the aircraft. The dynamic margin can be directly related to pilot opinion, and hence, handling qualities. This means that there are known bounds for the dynamic margin that will result in level 1 handling qualities. For an excellent paper on the subject, see Phillips [2].
It is always wise to design the aircraft for an appropriate dynamic margin rather than the static margin rule of thumb.
References
[1] Perkins, C. D., "Development of Airplane Stability and Control Technology," Journal of Aircraft, Vol. 7, No. 4, 1970, pp. 290-301.[2] Phillips, W. F., and Niewoehner, R. J., "Characteristic Length and Dynamic Time Scale Associated with Aicraft Pitching Motion, " Journal of Aircraft, Vol. 46, No. 2, pp. 572-582.
Friday, May 24, 2013
Comprehensive Design
ACSYNT
ADS
AVID (APEX, ACS, RAPT, PAGE)
AVL
Ceasiom
DAR Corporation
DATCOM
Desktop Aeronautics (and the Aircraft Design Workshop)
Hanley Innovations
J2Aircraft
Larosterna
Martin Hepperle
OpenVSP
Pace APD
Piano
RDS
X-Plane
ADS
AVID (APEX, ACS, RAPT, PAGE)
AVL
Ceasiom
DAR Corporation
DATCOM
Desktop Aeronautics (and the Aircraft Design Workshop)
Hanley Innovations
J2Aircraft
Larosterna
Martin Hepperle
OpenVSP
Pace APD
Piano
RDS
X-Plane
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