Uploaded March 2017 | Updated September 2026, 1 week ago
I'm starting a new series of videos called, you guessed it, In a Nutshell. These videos will be aimed at simplifying down complicated topics so that if you don't want all the detail and background, you can still get the gist of how these things work.
Let me know what you think!
I'm starting a new series of videos called, you guessed it, In a Nutshell. These videos will be aimed at simplifying down complicated topics so that if you don't want all the detail and background, you can still get the gist of how these things work.
Let me know what you think!
![Explained: Thermally Perfect Gas (TPG)
In this video, we will go through the derivation of why, for a thermally perfect gas (TPG), the energy and enthalpy are only a function of temperature, and not of two state variables. We will be using the combined 1st & 2nd law of thermodynamics (video [1] below for derivation).
RELEVANT VIDEOS
[1] : https://goo.gl/soiSr9
REFERENCES
:: Notes by Matt MacLean
:: Modern Compressible Flow, Anderson
:: Elements of Gasdynamics, Liepmann and Roshko
:: Gas Dynamics, Zucrow and Hoffman Explained: Thermally Perfect Gas (TPG)](https://i.ytimg.com/vi/prnGHlfCBrM/mqdefault.jpg)


![Explained: Tire Slip Angle
Lets talk about tire/tyre slip angles! Ill go through two ways of thinking about it. The first is the mathematical description, which will be useful for my later videos on vehicle dynamics. The second is the physical description of what is happening in the tire contact patch when a tire is operating at a finite slip angle.
NOTES
► One thing I forgot to make a note of is that even though the terminology calls it a slip angle, the rubber in the footprint is rarely slipping. In my foot-on-a-treadmill example, you can see that the only time the rubber starts to slip is towards the rear of the print. This is because towards the rear of the print, the normal (vertical) force pushing the rubber onto the road, and the friction coefficient between the road and the rubber, are no longer able to keep the rubber from sliding back to its undeflected position. Its more complicated than this, but thats the general reason.
RELEVANT VIDEOS
→ Tire Axis System
https://goo.gl/W4Y9iR
SEMI-RELEVANT VIDEOS BUT NOT REALLY
→ How to Calculate Top Speed
https://goo.gl/T4UvN4
→ F1 Aerodynamic Drag at Top Speed
https://goo.gl/oyStsp
THUMBNAIL PHOTO CREDIT
By Phil Guest (Flickr: [1]) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons Explained: Tire Slip Angle](https://i.ytimg.com/vi/rbhkfD1Dxo4/mqdefault.jpg)



![How To: Build Your Own Rubens Tube
In this video Ill show you how to build a DIY Rubens Tube! All the parts and steps are shown in the video and in the description below. Should you have any questions, feel free to leave a comment! If you want a detailed written document to follow, check out my blog post on the build at the link shown below in the LINKS section. If you want to see my tube in action, check out the songs listed in the SONGS section below.
LINKS
→ My blog post
https://goo.gl/ZfNiAP
→ Engineering Toolbox NPT
https://goo.gl/N9cQNf
SONGS
→ Lensko - Circles
https://goo.gl/cROa5P
→ Unknown Brain - Saviour
https://goo.gl/ldjdbR
→ K391 - Earth
https://goo.gl/8n4Cj1
→ Lensko - Cetus
https://goo.gl/3UQlOj
→ Lensko - Lets Go
https://goo.gl/VR7E17
WHAT YOU WILL NEED
- [1] Propane tank (grill LP 15 or 20 lb) ($30 empty + $18 fill)
- [2] Char-Broil Universal Propane Regulator with Nut (female 3/8 NPT) ($15)
- [3] Brass hex pipe nipple 3/8 MIP x 3/8 MIP ($3)
- [4] Gas ball valve 3/8 brass ($6.45)
- [5] Male Hose Barb Adaptor - 3/8 ID Hose Barb x 3/8 MIP ($3.79)
- [6] Vinyl tubing 3/8 ID x 1/2 OD ($0.39 per foot)
- [7] Nylon 3/8 barbed adaptor 90 degree elbow ($2)
- [8] 3 x 60 galvanized steel duct ($7.25)
- [9] 3 galvanized steel duct cap ($3.41)
- [10] Latex glove or balloon
- [11] Speaker (any kind you want)
- Duct/Aluminum/Foil tape ($3)
- PTFE thread seal tape ($1.50)
- Masking tape
- Ruler/tape measure
- Writing utensil
- 1/16 drill bit
- Drill
- Matches or a lighter
Total Cost = $50 (if you have a filled propane tank)
Total Cost = $100 (if you dont have a propane tank)
NOTES
► I dont have links to the parts in the list above, because I got everything at Lowes or Home Depot. If you go to the store, you will be able to find everything.
► The one thing the store didnt have in stock (but you can order it and have delivered to the store at no extra cost) is the 3 tube cap.
► Some songs might work better than others. The music needs to be in the correct frequency range for you to see the waves, so anything with frequencies that are too low or high probably arent going to look special.
► I switch between calling it a Rubens Tube and a Rubens Tube because Ive seen it both ways. It was invented by a guy named Heinrich Rubens, so the second naming style is the possessive, calling it his tube. But I also think the first naming style is fine and makes more sense if you precede it with an article (e.g. A Rubens Tube). If John Smith invented it, I feel like it would make sense to call it a Smith Tube, instead of a Smiths Tube. If you have strong feelings about this, let me know. How To: Build Your Own Rubens Tube](https://i.ytimg.com/vi/sQ3DCe5fziY/mqdefault.jpg)
![Explained: NACA 4-Digit GUI Part 2/10 [MATLAB]
This is the second video in my 10-video series on coding a program in MATLAB to compute, display, and save a NACA 4-digit airfoil.
IN THIS VIDEO:
We clean up the GUI layout after opening the .fig file in GUIDE. We make the widths of the components the same, as well as align boxes and buttons horizontally and vertically.
IN THIS SERIES:
Part 1/10 : https://goo.gl/9UBgbo
Part 2/10 : https://goo.gl/jRRcYJ
Part 3/10 : https://www.youtube.com/watch?v=SbW1NDuvdJQ
Part 4/10 : https://goo.gl/HwHB39
Part 5/10 : https://goo.gl/AlDne8
Part 6/10 : https://goo.gl/7n1QP7
Part 7/10 : https://goo.gl/nTGleR
Part 8/10 : https://goo.gl/ez247P
Part 9/10 : https://goo.gl/8mXYcc
Part 10/10: https://goo.gl/ovBlbW Explained: NACA 4-Digit GUI Part 2/10 [MATLAB]](https://i.ytimg.com/vi/spHG_XEP5-c/mqdefault.jpg)
![How To: Find Mach Number from a Picture (Part 1)
Want to look at a picture of a bullet/plane/etc. and be able to approximate the Mach number? In this video I show you three ways to find the Mach number from a Schlieren image.
Disclaimer: The Mach numbers I obtain are, as mentioned in the video, approximations. I understand that they will not be entirely correct, but these methods can be used to get good initial estimates.
Last Photo Note: On the news article (cited below), they state that the plane reached a maximum Mach number of 1.09. However, there was a Reddit post from someone who worked on the team that took the pictures, and he states the plane was flying at just under Mach 1.2 when the photos were taken. Here is the link to that post:
https://www.reddit.com/r/pics/comments/3iuouf/this_is_what_piercing_the_sound_barrier_looks_like/?limit=500
1st Photo Credit
By Settles1 (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
2nd/3rd Photo Credit
School of Aerospace, Mechanical and Mechatronic Engineering
University of Sydney, 1998-2004
4th Photo Credit
Tumblr: jefflownsbury-blog
5th Photo Credit
By NASA Langley Research Center, X-15 testing
6th Photo Credit
By NASA Glenn Research Center [Public domain], via Wikimedia Commons
7th Photo Credit
NASA photo
http://www.nasa.gov/centers/armstrong/features/shock_and_awesome.html How To: Find Mach Number from a Picture (Part 1)](https://i.ytimg.com/vi/sv8sj_TH1Kw/mqdefault.jpg)
![Explained: Lift Curve [Airplanes]
Lift curves are available for various airfoils and provide data relating the lift coefficient of the airfoil to the angle of attack. The lift curves described in this video are for 2D (infinite wing) airfoils. Actual 3D wing lift curves are complicated by 3D effects such as spanwise flow and tip vortices. See the links below for actual NACA data for both a symmetric and a cambered airfoil.
Angle of Attack:
https://www.youtube.com/watch?v=Fm2Az-PgPUU
NACA 0012 (Symmetric):
- The lift curve to look at is the lower of the two sloped lines
- Notice that at zero AoA, the lift coefficient is zero
- The horizontal lines are moment coefficient plots, which you can ignore for now
http://mshades.free.fr/flapping/Cz0012.jpg
NACA 2412 (Cambered):
- Lift curve is the left of the two plots
- Notice that the zero lift AoA is negative (approx. -2 degrees)
http://www.tricity.wsu.edu/htmls/mme/me439/s2007/naca2412.jpg Explained: Lift Curve [Airplanes]](https://i.ytimg.com/vi/tF_Z1lz7HKw/mqdefault.jpg)