Hot Air In The Aerospace Industry

Mankind’s adventures in aviation began with hot air, and it’s still kind of a big deal (for one particular EXAIR customer, that is) today.

How it started: In the 1780s, two French brothers, Joseph and Étienne Montgolfier, worked in their family’s paper mill. They noticed, along with everyone else, that pieces of paper were sometimes carried airborne in billows of smoke from the fires that heated the boilers. But unlike everyone else, they became curious as to why this happened…and how they might exploit this strange phenomenon to send something more substantial than some paper scraps through the air.

After a good deal of experimentation and trips “back to the drawing board” (they thought it was the smoke, not the heat, that caused the rise for a while), they began making public demonstrations of their first successful hot-air balloons in the summer of 1783. By autumn, having flown a sheep, a duck, and a rooster in a tethered balloon (to an altitude of about 1,500 feet on a flight that lasted about 8 minutes), they constructed a balloon large enough for two humans which flew successfully for almost half an hour, to a height of 3,000 feet. Early enthusiasts who came out to witness some of these flights included King Louis XVI, Queen Marie Antoinette, and American statesman (and quite the inventor himself) Benjamin Franklin.

The Montgolfier brothers decorated their balloons with the fleur-de-lis, zodiac symbols, and portraits of the King. I think it says a lot about ballooning that nowadays we have Sylvester the Cat, Tweety Bird, and even Spider-Pig.

How it’s going: I’m not going to lie; your level of fascination with the rest of this blog will depend on how fascinating you find the phenomenon of the Vortex Tube…which was, in fact, discovered by another French inventor, Georges Ranque:

The unique physical phenomenon of the Vortex Tube principle generates cold – and hot – air instantly, and for as long – or short – a time as needed.

Most Vortex Tube applications involve the use of the cold air flow, but a number of customers do indeed use the hot air flow. A material supplier to the aircraft & aerospace industry makes a flexible, porous strand of material that, after fabrication, passes through a wash tank prior to cutting to size. They wanted to speed up the drying time, but it was impractical to use electrically powered hot air blowers or heat guns. By using an EXAIR Model 3275 Large Vortex Tube set to a 70% Cold Fraction, they’re able to blow a little over 22 SCFM of 220°F air onto the strand, which effectively dries it to their specification, quickly & safely.

The EXAIR Vortex Tube. Cold air from one end; hot air from the other. Fully adjustable. You can use either…it’s fine with us; whatever you need.

Other EXAIR products that have been notably popular in the aerospace industry are engineered Air Nozzles, Static Eliminators, Air Amplifiers, and some even use Vortex Tubes & Spot Cooling Products for their COLD air flow. If you’d like to find out more about getting the most out of your compressed air system like the folks in the aerospace industry do, give me a call.

Russ Bowman, CCASS

Application Engineer
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