Aerodynamic - Blog Posts

#beard#gone#barber#cutthroatshave#feelsoyoung hopefully makes me more #aerodynamic for #football haha

10 Out of this World NASA Spinoff Technologies

What is a spinoff? Great question! A NASA spinoff is a technology, originally developed to meet our mission needs that has been transferred to the public and now provides benefits as a commercial product or service. Basically, we create awesome stuff and then share it with the world. Here’s a list of just a few NASA spinoff technologies (in no particular order): 

1. Enriched Baby Food

While developing life support for Mars missions, NASA-funded researchers discovered a natural source for an omega-3 fatty acid that plays a key role in infant development. The ingredient has since been infused in more than 99% of infant formula on the market and is helping babies worldwide develop healthy brains, eyes and hearts. 

2. Digital Camera Sensors

Whether you take pictures and videos with a DSLR camera, phone or even a GoPro, you’re using NASA technology. The CMOS active pixel sensor in most digital image-capturing devices was invented when we needed to miniaturize cameras for interplanetary missions. 

3. Airplane Wing Designs

Did you know that we’re with you when you fly? Key aerodynamic advances made by our researchers - such as the up-turned ends of wings, called “winglets” - are ubiquitous among modern aircraft and have saved many billions of dollars in fuel costs. 

4. Precision GPS

Uncorrected GPS data can be off by as much as 15 meters thanks to data errors, drift in satellite clocks and interference from Earth’s atmosphere. One of our software packages developed in the 1990s dials in these locations to within centimeters, enabling highly accurate GPS readings anywhere on the planet. One of our most important contributions to modern society, precise GPS is used in everything from personal devices and commercial airplanes to self-driving tractors. 

5. Memory Foam

Possibly the most widely recognized spinoff, memory foam was invented by our researchers looking for ways to keep its test pilots and astronauts comfortable as they experienced extreme acceleration. Today, memory foam cushions beds, chairs, couches, car and motorcycle seats, shoes and even football helmets. 

6. International Search and Rescue System

We pioneered the technology now used internationally for search and rescue operations. When pilots, sailors or other travelers and adventurers are stranded, they can activate a personal locator bacon that uses overhead satellites to relay their call for help and precise location to authorities. 

7. Improvements to Truck Aerodynamics

Nearly every truck on the road has been shaped by NASA - literally. Agency research in vehicle aerodynamic design led to the curves and contours that help modern big rigs cut through the air with less drag. Our contributions to truck design have greatly reduced fuel consumption, perhaps by as much as 6,800 gallons per year for an average vehicle. 

8. Shock Absorbers for Buildings and Bridges

Shock absorbers originally designed to survive the extreme conditions of space shuttle launches are now bracing hundreds of buildings and bridges in earthquake-prone regions all over the world. None of which have suffered even minor damage during an earthquake. 

9. Advanced Water Filtration

We have recently discovered sources of water on the moon and Mars, but even so space is still practically a desert for human explorers, and every drop possible must be recycled and reused. A nanofiber filer devised to purify water in orbit is currently at work on Earth. From devices that supply water to remote villages, to a water bottle that lets hikers and adventurers stay hydrated using streams and lakes, our technology is being utilized. 

10. Invisible Braces

A company working with NASA invented the translucent ceramic that became the first invisible dental braces, which would go on to become one of the best-selling orthodontic products of all time. 

So, now that you know a few of the spinoff technologies that we helped develop, you can look for them throughout your day. Visit our page to learn about more spinoff technologies: https://spinoff.nasa.gov

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Porsche 935 "Moby Dick" (1978) with the gorgeous Martini racing livery

Arizona - 2017

This turned into a longer post than I anticipated but whatever.

Something I've been seeing quite often in the comments under helicopter posts that make it to the broader internet spaces is discussions on autorotation. These discussions are mostly incomplete information at best and outright wrong at worst. A lot of people seem to be able to recall it as a fact about how helicopters can glide to a safe landing, but aren't aware of the actual process. So here's a guide on what an autorotation is, how its performed, and some of the nuances to it.

For the uninitiated, an autorotation is a maneuver that every helicopter is capable of performing which allows it to land safely in the event of a power failure. Even more simply put - its how a helicopter glides.

I've already made previous posts about helicopter controls and some principles of flight which I recommend checking out first if you're unfamiliar with those.

Under normal flight the engine(s) drive the rotors at a constant flight rpm and all control is made by pitching (changing the angle) The blades to make more or less lift. Essentially the same process as sticking your hand out the window of a moving car and making rise or fall in the wind. However the rotors are experiencing a lot of drag (wind resistance) which requires the engine to produce a lot of power to overcome and maintain rpm.

When an engine failure occurs there is no more power driving the rotors and the high drag will cause the rotor rpm to start to decay rapidly. If nothing is done about that then the rpm will fall so low that the rotors will stall or worse and the helicopter will fall out of the air like a rock. Thankfully we have the option to autorotate instead of that outcome.

The first thing that happens to initiate an autorotation is to fully lower the collective. This will flatten out the blade pitch and minimize the drag on the main rotor, slowing the rpm decay. As the collective is lowered the cyclic will need to come aft slightly to prevent the nose from dropping. Also the right pedal will have been pushed in as the power failure initially occured to prevent yawing.

Now the helicopter is in a steep descent and the autorotation has begun. The airflow through the main rotor has reversed from normal flight. Instead of being drawn from above and expelled downward there is a diagonally upward flow of air through the main rotor.

Now the rotor rpm will begin to rise again thanks to the special design of the rotor blades. A rotor blade has an airfoil shape which is sort of like an elongated teardrop with the wider end on the leading edge. This shape minimizes drag and maximizes lift. But the blade is also slightly twisted. It has a positive pitch at the root where the blade attaches to the rotor hub which gradually transitions to a negative pitch at the tip.

Because of this twist and the difference in relative speed along the blade length (tip travels relatively faster than the root) the blades will develop three distinct regions. These are the driven, driving, and stall regions

The driven and stall regions at the blade tip and root are still producing drag but the middle driving region is actually producing lift, in an upward and slightly forward direction. This forward lift is the thrust that causes the rotor rpm to increase during an autorotation.

So now you are in a descent and recovering rpm back to the normal flight range. If you leave the collective fully lowered the rpm will now start to increase past the normal range and begin to overspeed. If the overspeed becomes too great the blades will be damaged and one could eject. Not ideal.

You have to manage the rpm manually to prevent it from becoming too low or too high. You also do this with the collective. Remember, to start the auto you should lower the collective fully to minimize rpm loss initially and then to start recovering it. As the rpm reaches the normal range the collective should be raised again just a bit to "catch" the rpm. Now you can manually adjust rpm with a tiny amount of collective movement. Rpms a little too fast? Raise it a bit. A little too slow? Lower it a bit. What this is doing is changing the size of the driven and driving regions of the blade, thanks to the twist. Lowering the collective grows the driving region and shrinks the driven region, and vice versa for raising it.

Now the helicopter is safely gliding and can be steered to a landing spot. There's not much to do until you're approaching the ground. The next maneuver will be the level and flare. The height at which you initiate the level and flare depends on the helicopter. Generally a larger helicopter will have more momentum and need to start the maneuver sooner.

Starting with the level off. You will be gliding with a high rate of descent and forward speed in an autorotation. The purpose of the level off is to drastically reduce the rate of descent. By using some aft cyclic input you will pull the nose up and put the helicopter in a level flight attitude. This causes the upwards lift of the rotor disc to act as a sort of parachute and arrest the descent.

Now with the descent rate minimal you apply more aft cyclic to pitch the nose up further and neutralize the forward speed. This is the flare and its the last opportunity to build rotor rpm in an autorotation.

Now you are just over the ground with little to no forward speed and the helicopter will start to settle and sink. Apply forward cyclic to level the helicopter parallel with the ground and use the pedals to keep the nose pointed straight ahead. Then you have whatever rpm is built up to cushion the landing. Smoothly raise the collective fully as the helicopter sinks to touchdown and the landing can be shockingly smooth.

What an autorotation really comes down to is energy. You often start at a high-ish altitude with some forward speed and this becomes the potential and kinetic energy you trade to power the rotors instead of the engine. The energy is an absolute requirement though. If you dont have enough of a combination of speed and/or altitude then an autorotation can be impossible. There are phases of flight and certain missions where you have to accept the risk of a power failure and rely on the crash-worthiness of the airframe.

Despite that, I've done a lot of engine failure procedures in small planes and helicopters and 9 times out of 10 I would rather experience a real one in a helicopter.