Airfoils

An airfoil is the shape of a wing . There are many shapes but the most common are symmetrical, asymmetrical or cambered airfoils.

Common Airfoils

Common Airfoils

Also see Airfoil Sections by Kiwi John Malkin.

NACA 0015 (naca0015-il) Airfoil

naca4digit

NACA 0016 Airfoil

naca4digit

NACA 2412 (naca2412-il) Airfoil

naca4digit

CLARK Y Airfoil (clarky-il)

Clarke Y

Airfoil Eppler 168 15% width

E168 (12.45%)

Javafoil Simulator

Digital airfoil analysis <3

How do these work?

There are several factors to consider when trying to understand how a wing works, each factor together helps generate the force of lift.

1. Air deflection with angle of attack & Coandă effect

This is how a flat wing will fly, air under the wing is deflected down and by the Coandă effect air above the wing is guided along its surface and down as well. The air is slowed and deflected down by the wing it pushes the wing up and back. This is lift and drag.

Wings need to deflect air downwards which can be achieved using symmetrical, asymmetrical or cambered airfoils.

By Cruithne9 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=53650245

2. Bernoulli’s principle

Bernoulli’s principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid’s potential energy.

This means that faster flowing air (on top of the wing) exerts less pressure than the slower air beneath the wing. This pressure difference creates an upwards force – lift.

This explanation has obvious problems such as:

  • Then how can a plane fly upside down?
  • Some models have flat wings, they fly just fine.

The principle also mentions that the faster air ontop of the wing meets up with the slower flowing air underneath at the trailing edge – this is incorrect.

https://www.discoverhover.org/infoinstructors/guide8.htm

Videos

Yeah cool story bro I just want to watch a video :D

References

Linux Commands

Quick docker container to have a hoon

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docker run -ti --name ubuntu-c ubuntu
docker start -i ubuntu-c

Update & Upgrade

pt-get update downloads the package lists from the repositories and “updates” them to get information on the newest versions of packages and their dependencies.

apt-get upgrade will fetch new versions of packages existing on the machine if APT knows about these new versions by way of apt-get update

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apt-get update
apt-get upgrade

--- Install application `zip` & `unzip`. Check version and example use.
apt-get install zip unzip
zip --version
unzip content.zip

--- applications
python3, python
nano

Misc Commands and magic

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--- Misc Commands

ll ~ list files (simliar to DIR)
la ~ list files horizontally
rm -r [DIRECTORY NAME] ~ delete directory
rm -fm [DIRECTORY NAME] ~ delete directory with files in it
mkdir [DIRECTORY NAME] ~ create directory
sudo ./sbin/shutdown -r now ~ reboot
sudo ./sbin/shutdown -h now ~ omit now to schedule a shutdown
sudo -i ~ switch to the root user

--- Hardware Related

htop ~ system-monitor process-viewer and process-manager
top ~ this is like the windows task manager
grep -c ^processor /proc/cpuinfo ~ CPU core count
free -m ~ displays memory usage

Text Editor

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nano postgres.sh                 ~ edit and create the file
chmod +x postgres.sh ~ mark as executable
./postgres.sh ~ runs the script

VMware Workstation Player

This is a free VM player that can run on Windows 10, you create a new virtual machine and install the OS from an ISO file.

When you create VM Images they reside locally at :

  • C:\Users[Windows User name]\Documents\Virtual Machines[Machine Name]

macOS High Sierra

Currently this only works for version 12 of VMware Workstation Player and you will need to patch it with unlocker208, details in the links below.

Glow Engines

A glow plug engine, or glow engine), is a type of small internal combustion engine typically used in model aircraft, model cars and similar applications. I don’t really fly these engines as petrol engines are more reliable but I do refurbish and collect them.

Stripped OS 46 AX

The number stamped on the engine is the size or displacement measured in cubic inches (ci). I only understand cubic centimeters (cc) as this is what my car is measured in (1400 cc). To put this into perspective a 61ci glow engine is a 10cc

These are the engines I had in my collection in South Africa: ASP 108 A, ASP 91 A, ASP 61-AII, ASP 52-AII, ASP 46a, IRVINE 46, ASP 36-AII, ASP 25-AII, AP 15, OS 15 LA, ASP 12A and ASP 09

ASP 108 A

This is a 17cc engine, for is power to weight it is rubbish but I do like the shiny head! The ‘A’ means the carbs high speed needle is located on the carb and not remotely – Im told this is more reliable in terms of fuel/air mixture but its not safe as your fingers get very close to the prop.

ASP 108 A

ASP 91 A

Power to weight this is a very good engine, I have 2 the one has a broken crank shaft and both are missing the high speed needle valves. Perhaps one day I will rebuild and run them both. These are 15cc engines.

ASP 91 A

Irvine 61

Nice and clean but missing the exhaust nut and bolts. These are no longer made so will have to try match from and ASP if possible.

Irvine 61

ASP 61-AII

This is a a 10cc engine with a remote carb.

ASP 61-AII

ASP 52-AII

This engines remote carb mount is broken but its in very good shape otherwise. This engine is 8.5cc

ASP 52-AII

ASP 46a

These are very common engines, mine has an OS 46 exhaust and the one head fin is damaged but it runs 100%. This is a 7.5cc engine.

ASP 46a

Irvine 46

This engine’s carb mount is broken and its missing its exhaust, the block can be fixed but I will try source another block and rebuild it.

Irvine 46

ASP 36-AII

This is a fantastic size engine for a shotgun with a displacement of 5.8cc. This one needs some cleaning but Im reluctant to as I may actually want to fly it.

ASP 36-AII

ASP 25-AII

This would probably work pretty well in a shotgun, it has a 4cc displacement. The remote part of the carb has been removed and the high speed needle attached to the carb – I think the previous owner did this for reliability.

ASP 25-AII

AP 15

I’m not sure about the history but this ‘AP’ was manufactured by ASP and its a 2.4cc

AP 15

OS 15 LA

I think the LA/AX ect lettering on these OS engines is got something to do with the ports (in/out) in the combustion process. Apparently the AX range are racing engines but I really don’t know. My little 15 LA is pretty dirty and needs a cleanup.

OS 15 LA

ASP 12A

I prefer this ‘classic’ exhaust porting on these tiny engines, this is a 1.9cc

ASP 12A

ASP 09

This is the smallest I own, the block is exactly the same as the ASP 15. This 09 is a 1.4cc which means my old KIA Rio’s displacement was 1000 times more – really puts things into perspective!

ASP 09