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Old 02-28-2007, 05:32 PM
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Default "The USAF Torture Chamber" (or "When Florida Freezes Over")

Question:

Where on the face of the planet can you go where it's 85 degrees and sunny, and fifteen feet away it's 65 below zero with blowing ice?

Answer:

Florida

Yep! You read right. More specifically, the Florida panhandle.

One of the better-known landmarks here at Eglin AFB is the McKinley Climatic Laboratory. The military's answer to "How can we test it in ALL environments BEFORE it goes into service?".

It's the US military's largest insulated hangar.

252 feet wide, 201 feet deep, seven stories high.

3.5 MILLION cubic feet.

It can accomodate a C-5 aircraft...or two companies of infantry with field gear, weapons, and vehicles.

The front doors of the hangar (200 tons each) open to each side to the full width of the main chamber.
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Old 02-28-2007, 05:40 PM
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The McKinley Climatic Laboratory encompasses six chambers, each with its own capabilities.

The main chamber, which can handle a C-5 Galaxy, is the largest and busiest section. Able to create any temperature between minus 65 and 165 degrees, its humidity range is from 10 to 100 percent. At 252 feet wide, 201 feet long and 70 feet high, it has 55,000 square feet of useable floor space. And it allows for limited live firing.

The equipment test chamber is the second most used area. Much smaller than the main chamber at 130 feet long, 30 feet wide and 25 feet high, it allows for a broader temperature range ? minus 105 to 170 degrees ? and a quicker rate of cooling and heating rate. Aircraft engines and small vehicles or equipment such as trucks and turbine-driven ground power units are tested here.

The sun, wind, rain and dust chamber is 50 feet long, 50 feet wide and 30 feet high. Built primarily for heat tests, it creates temperatures between 60 and 170 degrees in four to six hours depending on outside ambient conditions.

The all-weather room has its own refrigeration machinery and can create temperatures between minus 80 degrees and 170 degrees. The maximum cooling rate is 60 to minus 80 degrees within 48 hours and a heating rate from 60 to 170 in eight hours. It measures 44 feet long, 22 feet wide and 15 feet high.

The salt fog chamber uses two steam-fed heat exchanges to create temperatures between 70 and 149 degrees. Designed to provide an ambient test site away from the other test rooms because of the corrosive nature of the salt fog conditions, it sits outside McKinley?s main structure. It measures 54 feet long, 16 feet wide and 16 feet high.

The temperature-altitude chamber uses the same refrigeration machinery as the all-weather room, but its extremely small size ? 13 feet long, nine feet wide and six feet high ? allows for rapid condition changes. With precooling, the chamber?s temperature can drop from 70 to minus 70 degrees, with pressure reduction to 50,000 feet, in 12 minutes. Temperatures as low as minus 70 degrees and altitudes as high as 77,000 feet have been reached.


Recent testing was done on the F-22 Raptor.

Here's the Raptor at -65 F
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Old 02-28-2007, 05:52 PM
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The climatic laboratory reproduces virtually every type of weather possible ? sandstorms, blizzards, sleet, downpours of up to 25 inches per hour ? but its primary concern is excessive heat and cold that plague aircraft avionics and hydraulic systems.

Stoking its main chamber to a maximum 165 degrees, which takes about eight hours, McKinley crews literally put avionics equipment on an oven rack by adding powerful solar lights. Why such intensity? Because avionics gear already generates heat, it?s taxed even more in regions such as Southwest Asia, where temperatures inside closed cockpits can hit 190. It?s better to find problems at the lab than in battle.

As for low temperatures, they thicken hydraulic fluid, causing problems for flight controls, landing gear and bomb-bay mechanisms. Hence, in 20 hours lab workers turn Eglin?s most famous landmark into the world?s biggest deep freeze, replicating arctic conditions at minus 65 degrees.

?A lot of modern aircraft, such as the F-117, B-2 and F-22, have imbedded engines,? McKinley?s lab director noted. ?So we create icing clouds and then blow them over engine-running aircraft to probe internal anti-icing systems. If you don?t have any way of heating engines, ice chunks can be sucked down into them, resulting in severe damage.?

During these experiments, lab temperatures become so cold, ?it feels as if your fingernails will pop off,? said test advisor Roger Judy.

McKinley staffers primarily evaluate weapon systems during full-scale development, looking for significant glitches before mass production starts. Afterward corrections are made, followed by ?tests to the fixes.?


F-22 at 120 degrees F

Note the anchor chains. The engine exhausts are attached to ducts at the rear of the hangar.

An F-16 can be restrained and tested at full throttle with afterburners.
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Old 02-28-2007, 06:13 PM
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The climatic lab's origin dates back to World War II.

In the winter of 1942-43, the Allies discovered, with raised eyebrows, that the Luftwaffe couldn?t get its aircraft airborne during subzero weather. This grounding of all their planes made it clear to U.S. military leaders that cold weather testing was necessary.

In September 1943, Col. H.O. Russell and Lt. Col. Ashley C. McKinley began developing new and innovative cold-weather testing techniques. Based on his experience ferrying aircraft to the Soviet Union, McKinley believed all U.S. aircraft and equipment should be operable at minus 65 degrees. Consequently, he suggested a refrigerated hangar be constructed at Eglin to produce environmental extremes under controlled conditions.

The first aircraft test, conducted on P-51 Mustangs, started in May 1947 under a simulated arctic environment at what was then called the Climatic Hangar, with temperatures reaching minus 70. Renamed for McKinley after his death in 1971, the lab for the past 47 years has tested almost every type of U.S. military hardware.
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Old 02-28-2007, 06:31 PM
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Testing the F-22

The standard press photo for a test subject in the McKinley lab most often shows an aircraft parked and covered in snow. The first photo, from 24 May 1947, shows six aircraft?including a Lockheed P-80?in the main chamber. The photos create an impression that the tests done in the lab are static. In actuality, the tests are almost all highly dynamic, with pilots in the cockpit, maintainers and crew chiefs working in the elements, aircraft systems operating, and engines running.

The lab is one the few facilities in the world where jet engines can be operated in a closed hangar, so air has to get in and exhaust has to get out in order for the engines to run. That air also has to be the same temperature as the test chamber. Otherwise, the results aren?t accurate.

The lab gets that much air from a huge storage tank outside the hangar. The tank provides up to 800,000 cubic feet per minute of either pre-conditioned hot or cold air (depending on the test) to replace the air inhaled by the engines on a real-time basis. The same amount of air goes in the chamber as comes out. When the tank is completely emptied, it takes approximately twenty-four hours to replenish the reservoir with conditioned air, particularly with extremely cold or extremely hot air needed for tests in extremely cold or hot conditions.

?Every project is unique,? adds Velasco, who has worked at the lab for more than eighteen years. ?We had stealth aircraft in here before, so we have dealt with special materials. But every vehicle has its own unique tie-down requirements and ducting needs.? In the case of the F/A-22, a Y-shaped duct, fitted with a system to dampen the exhaust at the back of the aircraft and keep the rest of the tube cool, is built so the aircraft?s two engines can be run during the tests. A separate duct?one set up so the small door on the aircraft?s top-mounted auxiliary power unit can open?is constructed and installed by the lab?s onsite team.

Once installed in the chamber, the Raptor looks like a creature out of a science fiction movie. With ducting in place, the aircraft is tied down in multiple places (each tie-down being equipped with strain gauges to measure stress on the airframe during the tests) and perched on jacks so the landing gear could be cycled and the hydraulics checked. Several small, movable, modular buildings surround the aircraft to house the twenty or so people necessary (including a fire chief) to conduct each test. The picture is made complete by the ski resort-type snow cannons, wind machines on the floor or, alternatively, banks of heat lamps or rain making equipment suspended from the ceiling on a rack shaped to the planform of the aircraft.

The elaborate apparatus is necessary. The weather extremes, the sophistication of the tests, everything is geared to one goal: ?We want to match operations in the real world. We want to see if the Raptor can take it,? Poulson observes.

Going to Extremes

Each of the environmental tests begins just like an F/A-22 flight. The pilot and crew chief perform a walk-around of the aircraft then the pilot climbs the ladder and straps into the cockpit?regardless of the conditions in the chamber. The pilot starts the engines and operates various systems on the aircraft in each weather condition. ?Part of the tests are to run the checklists,? adds Poulson. ?We want to see how the cockpit warms up and how the aircraft warms up. If it is raining, the pilot gets wet.?

The aircraft is subjected to all manner of weather extremes in a battery of separate tests. The individual trials range from cold soaking the aircraft at minus sixty-five-degree cold before ?warming? it to minus forty degrees; to a buildup of eight inches of snow, which at about twenty pounds of weight per square foot over the approximately 1,000 square feet of surface area on the Raptor results in a load of 20,000 pounds on the top of the aircraft; to a wind-blown snow at approximately forty-four feet per second. And that?s just the cold stuff.

After the snow melts (and is cleared through large drains in the chamber floor to a special retaining pond), heat testing begins. The trials start at a comfortable eighty degrees and build up to 120 degrees with the engines running. A later battery of tests subjects the aircraft to ninety-five degrees with seventy-four percent relative humidity and 105 degrees with eighty percent humidity to see where condensation occurs inside the aircraft.

Then the rains come. In one test, Raptor is inundated with 1.4 inches of rain per hour for close to eight hours to see how the drain holes on the bottom of the aircraft perform. Wind-blown rain tests identify where puddles may form in the weapons bays and in other openings. These tests are followed by an overnight in freezing rain. The resulting ice requires almost 1,200 gallons of deicing fluid to thaw the aircraft. The ice test is followed by a ground fog test at zero degrees and a vortex icing test (where the engines suck in standing ground water) to see where ice forms in the engine inlets.

?That is about the normal range of tests most aircraft are put through,? notes Wayne Drake, the lab?s technical director. ?The programs are very thorough.?

Concurrent with the aircraft tests are maintenance, loading, and auxiliary equipment tests. ?You have many more problems in the cold,? says MSgt. Paul Stauffer, one of the Air Force technicians who weathers the conditions with the F/A-22 as the tests progress. ?Equipment that is supposed to work even at minus twenty degrees acts differently at minus forty,? he says. ?The Raptor is no exception.?

After one cold-soak, the canopy would not close because the power-operated systems stopped working. The maintainers helped the pilot close the canopy manually before the next test, an engine run at minus forty degrees, begins.

Once, an auxiliary power unit failed and had to be replaced in the cold. ?That actually worked out,? notes Poulson. ?Changing an APU at low temperatures is one of the maintenance points we want to check.? Adds TSgt. Greg Auzenne, another crew chief participating in the tests, ?Even simple things require more thought and effort at these conditions. Moving an equipment cart three feet can take twenty minutes because of the ice and snow.?

In one particularly arduous test, maintainers load four AIM-120 missiles in the F/A-22?s main weapons bay and an AIM-9 missile in one of the side weapons bays. They also attach underwing external fuel tanks and load the jet?s main tanks with fuel?all the while wearing full chemical/biological warfare gear with the temperature in the chamber set at zero degrees Fahrenheit.

?We change a battery in the blowing rain and we perform a pre- and post-flight inspection in the blowing snow,? explains Stauffer. ?We are validating the maintenance database just by doing the things that will be typical flightline crew chief jobs. The conditions we work in aren?t always great, though.?

At the completion of the tests, the aircraft is returned to flight status. After a functional check flight on 9 September, the Raptor leaves Eglin for Edwards. It makes an intermediate stop at the Lockheed Martin plant in Fort Worth, Texas. Company employees, who build one-third of each F/A-22 in Texas, are treated with their first look at the complete fighter. The aircraft is flown back to Edwards on 17 September.

?Overall, we found a few aircraft anomalies in the climatic lab, and we will have to go tweak them,? concludes Poulson. ?Nearly all of the tweaks will be minor software adjustments, though. The engines start slower in the cold and the rest of the systems depend on the engines for power. How those engines come up and how the power is distributed is a software fix. But those are the kinds of things we came to Eglin to learn.?

The McKinley Climatic Laboratory is truly a matchless national resource. With its unique capabilities, there is little wonder why this facility has been designated as a National Historic Mechanical Engineering Landmark. But the bottom line is practicality.

?We have tested the F-22 in every conceivable operational condition,? says Drake, who has been at the laboratory for nearly thirty years. ?Getting the same kind of data we get here in three months would have taken years without this facility, and at a much greater cost. We now know the F-22 can work in the weather.?
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Old 03-01-2007, 01:06 AM
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That was some interesting reading , Thanks Steve
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