The First Helicopter Medevac Missions

For a six-week period in the summer of 1945 as fighting raged between American and Japanese forces on the island of Luzon in the Philippines, six helicopter pilots flew the first rotary-wing medical evacuations under enemy fire in history. Although the helicopter had been used in combat in the Burmese theater of operations in April 1944, the Luzon airlift was first to take place under enemy fire. And here's the really crazy part of the story- the six American pilots were there not for medevac flights, but for repair and supply work! Project Ivory Soap began as concept to use Army-owned supply ships as floating repair depots that could move with the US forces during the Pacific island-hopping campaign. Early in the campaign, it could take weeks, even months, for replacement parts to arrive at front-line units from the United States. Under Project Ivory Soap, USAAF aircraft could be turned around more quickly with the floating depot ships nearby. By December 1943, the program had evolved into using six Liberty ships and eighteen smaller vessels. The ships had helipads constructed on them so that Sikorsky R-4s could shuttle between the ships and airfields ashore with critical parts.

In June 1945 the campaign to liberate the Philippines from Japanese occupation was underway and three of the Liberty ships were deployed to Luzon with the Fifth Air Force while the other three Liberty ships were deployed to the Marianas to support B-29 Superfortress operations with the Twentieth Air Force. On 15 June, R-4 pilot Louis Carle received a request to pick up two soldiers with head injuries 35 miles east of Manila. With only 25 hours of helicopter time and no medical training, Carle arrived at the designated spot but they couldn't locate the two soldiers needing evacuation. Men at the scene who greeted Carle had him fly out a platoon leader with a hip injury instead but they couldn't fit the stretcher into the R-4. Carle ended up removing the other seat and laying the injured soldier on the floor.

News traveled throughout the area of the successful helicopter evacuation and soon Carle and the other pilots of the repair ships were getting requests for additional medevac flights. Given the primitive state of helicopter technology of the day, the flights into combat zones were grueling and often the six pilots were flying as many as six to seven medevac missions a day. Often the pick up points were near front line areas and the helicopters were attractive targets to Japanese units. Mortar and artillery rounds often impacted near the landing zones as well, and adding to the stresses, the pilots were the only crew aboard and they had to load the injured, make sure they were secured, and then fly their flimsy machines out of the combat zone to a field hospital near Manila. As the American forces pushed into the highlands of Luzon, performance of the R-4 and later R-6 helicopters suffered and often Carle and his men had to overspeed the piston engines to get enough rotor lift to get airborne, all while avoiding enemy gunfire.

Carle and another pilot survived crashes of their respective R-4s after ten days. Both men were escorted out of the jungle highlands by appreciative Army units. With his repair ship heading to Okinawa to support the combat effort there, Carle would be officially credited with 12 saved soldiers though the actual numbers were likely quite higher. To replace the departing ship, another repair depot anchored in Manila Bay on 25 June and the four pilots aboard managed to medevac 40 injured soldiers in just four days. To make the medevac flights more comfortable for the wounded soldiers, the helicopter mechanics welded Stokes litters (steel tube and wire mesh baskets for carrying wounded) to the steel frames of the R-4 helicopters.

Of all the injured servicemen flown out of harm's way by helicopter in the Pacific Theater, 60 percent of those medevac flights took place on Luzon in that six week period. One-hundred fifty men are estimated to have been flown out and while this small number is nearly insignificant compared to the 40,000 saved by medevac flights in Korea and 1 million saved in Vietnam, the history making flights of Louis Carle and his fellow pilots in their flimsy Sikorsky R-4s convinced a skeptical military command of the value of the helicopter.


Source: Air & Space Smithsonian, July 2010, Vol. 25, No.2. "Medevac From Luzon" by Roger Connor, p62-67.

The 1938 Hurricane Relief Flights That Led to the Air Transport Command

The relief efforts following natural disasters have often reminded me of the first humanitarian airlift in the United States after a natural disaster. It was September of 1938 and one of the few Category 5 storms to strike the US mainland had just come ashore with unprecedented destructiveness in New England, causing widespread devastation throughout Long Island, Connecticut, Rhode Island, and Massachusetts.

While the forecasting technology of the day paled in comparison with what we have today, there are sufficient meteorological records from 1938 that give an impressive picture of what historians call "The Long Island Express". The storm formed off the coast of West Africa and tracked westward. Lacking offshore weather buoys, the US Weather Bureau (the National Weather Service's predecessor) relied on reports from ships at sea to track the progress of the storm. From a climatological standpoint, most hurricanes in the late part of the hurricane season that form in the Eastern Atlantic usually track to the west and curve back to the northeast, remaining out to sea and having little effect on the US East Coast.

However, on the morning of 21 September 1938 as the storm was off the coast of Norfolk, Virginia, it made a sudden veer due north instead of continuing out to sea on a northeast heading. Not only did this storm head due north for New England, it also picked up speed with a storm motion of 70mph, making the "Long Island Express" one of the fastest moving hurricanes in recorded history.

The sudden change in direction caught most of New England unprepared and when the hurricane made landfall that night, wind speeds gusting to as high as 185mph were recorded along the coast of New England. The extreme forward speed of the storm made the right quadrant winds 70mph faster than they were and this put Long Island, Rhode Island, and eastern Massachusetts square in the crosshairs of this monster. A 12+ foot storm surge slammed into Providence, Rhode Island and all throughout the area, lines of communication were cut- roads, railroads, phone and telegraph lines. Not until Hurricane Andrew hit Florida in 1992 would there be a storm that caused as much damage as "The Long Island Express". The Boston area found itself cut off from the rest of the nation as thousands were made homeless and the local infrastructure of the area was destroyed.

Enter C.R. Smith. Two years earlier Jack Frye of TWA decided the US airline industry needed a common voice to work with the government in improving air safety and efficiency. He managed to convince C.R. Smith of American, Eddie Rickenbacker of Eastern, and Pat Patterson of United to form the ATA- Air Transport Association. Headed by a former military aviator of unqualified technical experience, Edgar Gorrell, one of the ATA's first acts under Gorrell was to propose that the airlines form a plan to organize their resources in the event of a national emergency to form what Gorrell called a "civil reserve air fleet".

Now keep in mind that this was a time when the airlines were run by rugged individualists like Rickenbacker or Smith. Just the fact that four disparate personalities of the magnitude of Smith, Frye, Rickenbacker, and Patterson even agreed to form the ATA was a miracle in and of itself. But to form a unified plan in case of national emergency? The other member airlines of the ATA balked at the idea despite Gorrell's pleadings- "If we don't have our own plan, the government will shove one down our throats!" But only one airline president backed the ATA proposal and that was C.R. Smith of American Airlines. The ATA proposal languished for two years until that dark night that the "Long Island Express" came ashore.

The only airline that operated on the New York-Boston route was American Airlines and C.R. Smith immediately assigned every available DC-3 the airline had to fly humanitarian missions to Boston Logan Airport which was pretty much the only functioning airport in the area in the hurricane aftermath. Flights were cancelled throughout American's system as DC-3s were pulled for the airlift. Within 24 hours, C.R. Smith realized the job couldn't be done alone- usually American carried 200 passengers a day between Boston and New York and on the first flight out of Boston, over 1000 people were looking for seats on American's mercy flights. With the local authorities also wanting to deploy medical personnel as well as rescue and construction crews to New England, American needed help.

C.R. Smith phoned Edgar Gorrell for an urgent request for help- Gorrell in turn telephoned Jack Frye at TWA, Eddie Rickenbacker at Eastern and Pat Patterson at United. Each of these airlines had the most capable airliner of the day, the DC-3, and Gorrell asked them to pull their DC-3s out of service to fly the humanitarian airlift. Without question, without argument, the three airline presidents had DC-3s streaming into Newark within hours of Gorrell's call. He then secured temporary route authority for them to fly the New York-Boston route from Washington (the nation's airlines had their route structures regulated by the federal government in those days).

For the seven days following the hurricane's landfall, the four airlines operated 24 hours a day, flying over 60,000 tons of medical supplies into Boston, carrying over 1000 rescue workers into the area, and flying out over 1500 refugees out of the area. Those numbers pale in comparison to the airlift that took place after Hurricane Katrina in 2005, but keep in mind that the DC-3 only carried 21 passengers and was the state of the art in 1938. American and TWA even added their older DC-2s to the airlift. Newark, as the bridgehead of the airlift, was the scene of unprecedented cooperation by the rival airlines. American's crews often led formations of other aircraft to Boston as some of TWA and United's pilots had never flown on the East Coast. Airlines shared spare parts, even mechanics to keep the airlift running.

By the time the airlift ended and the airlines and their personnel returned to normal operations, Gorrell as well as the presidents of the four airlines realized the potential of the US airline industry to step up to the plate in times of crisis. When the first bombs dropped on Pearl Harbor just three years later, Edgar Gorrell already had a template in place to organize the US airline industry to provide airlift for the war effort- during the Second World War, the Air Transport Command (ATC) was formed by the US airline industry with government backing. And to head this massive undertaking, Edgar Gorrell turned to C.R. Smith. Not only did C.R. Smith demonstrate initiative in organizing the 1938 airlift, in 1940, a full year before Pearl Harbor, C.R. Smith had already had his own experts formulating an emergency war mobilization plan involving all of the US airline industry.

On 13 December 1941 President Franklin D. Roosevelt was prepared to sign an executive order to nationalize the US airline industry. Sitting in the Oval Office with FDR on that day were Edgar Gorrell and the chief of the US Army Air Corps, General Henry "Hap" Arnold. Both of them convinced FDR to tear up the executive order as Gorrell showed the President C.R. Smith's war plan to mobilize the airlines. In his postwar autobiography Global Mission, General Arnold noted that air power was useless without air transport.

Source: When the Airlines Went to War: The Dramatic, Never-Before-Told Story of America's Civilian Air Warriors by Robert J. Serling. Kensington Press, 1997.

Alaska Airlines' First Jet, "Seventy-Seven Hotel"

Throughout the 1950s, Alaska Airlines' propliners wore a very elegant blue scheme with a golden eagle logo on the tail. The services from the lower 48 states to Alaska as well as on internal Alaska routes were advertised as "Golden Nugget" service in reference to Alaska's rich prospecting history. But despite popular services, Alaska in the 1950s was financially strapped and woefully unable to finance new equipment. At one point, Howard Hughes even offered to lease Alaska up to six Convair 880s to get into the jet age at very reasonable prices that unfortunately, were still too stiff for Alaska's austere budget.

But jets were what were needed and Alaska's competitor, Pacific Northern Airlines, had just ordered the Boeing 720 for delivery in 1962. There was simply no way for Alaska's DC-6s to compete with PNA's 720s on the Anchorage-Seattle run.

Charlie Willis, then Alaska's president, approached Convair to plead for very favorable financial terms to get jet equipment as Alaska saw the greater speed of the CV-880 as one way to meet the threat to market share posed by PNA's Boeing jets. Fortunately for him, Convair's sales team was desperately looking for a sale as the Convair jet was facing tough competition from the larger Boeing 707s and Douglas DC-8s. Willis returned to Anchorage with a contract for one Convair 880M, which boasted a whole range of improvements over the first baseline 880 model.

Of course, Convair was more than happy to be able to place one of their jets right in Boeing's hometown of Seattle where Alaska had a large presence in the late 1950s and early 1960s. N8477H (often called Seventy-Seven Hotel by Alaska crews) inaugurated Golden Nugget Jet services between Seattle, Anchorage and Fairbanks on 30 August 1961 and the service was cleverly pitched as "Four Jets Daily to Alaska".

Alaska's single CV-800 had high utilization as it was Alaska's only jet until the first Boeing 727s arrived in 1966 and Seventy-Seven Hotel was sold to Cathay Pacific. At one point, Alaska's sole 880 even carried cargo in the lounge area of the aircraft when demand was down in the winter months. The livery Alaska used on the CV-880 was based on the stylized eagle logo used on the DC-6s, but instead of blue, a very attractive red/gold scheme was used that was unique to Seventy-Seven Hotel and was not used on the rest of Alaska's fleet. The 727s that replaced the 880M had a Golden Nugget "meatball" style logo on the tail instead of the eagle on a red field. So not only was Alaska's 880 unique, it also wore a livery unique to it as well.

Source: Convair 880 & 990 (Great Airliners Series, Volume 1) by John Proctor. World Transport Press, 1996, p27.

The Drug-Busting Night Wolves of VAW-77

I had earlier featured US Navy E-2 Hawkeye squadron VAW-77 "Night Wolves" and the crucial role they played during the rescue efforts in New Orleans during Hurricane Katrina. It turns out that VAW-77 is a very unique squadron within the US Navy on several counts. Though a Reserve unit no different than many of the reserve air units of the different branches of the US military, VAW-77's primary mission is Counter-Illicit Trafficking (CIT) and as such, they are not required to operate from aircraft carriers and therefore its pilots do not have to go through carrier qualifications.

Eighty percent of the squadron's flight hours are devoted to CIT operations and when operating from several locations in the Caribbean and Latin America, fall under the jurisdiction of US Naval Forces Southern Command as part of the Joint Inter-Agency Task Force South (JIATF SOUTH). Deployments depend upon intelligence received from a variety of sources. During CIT missions, the E-2 is paired up with another air asset that acts as the "low bird" while the Hawkeye operates as the "high bird" cueing the "low bird" to targets of interest. In most circumstances, the "low bird" is a Navy P-3 Orion or a US Coast Guard HC-130 Hercules. Other times the "low bird" role may be filled by aircraft of cooperating nations in the Caribbean and Latin America. At times, the E-2 has to act in both roles, dropping down to low altitude to make visual contact, but this is done as little as possible as it's a less than ideal tactical arrangement.

In 2009, VAW-77 flew over 2,000 hours of CIT missions that aided in the seizure of 17.2 metric tons of cocaine and also assisted in the rescue of 15 individuals.

The other 20% of the squadron's flying time is devoted to Fleet Support and Homeland Defense. The Fleet Support mission usually entails area surveillance for the missile ranges of the Gulf of Mexico while Homeland Defense missions can include border surveillance and airborne control of air defense assets. In addition, VAW-77's E-2 Hawkeyes have been tasked with providing surveillance for Air Force One and range control during Space Shuttle and rocket launches from Kennedy Space Center/Cape Canaveral. When other E-2 squadrons have downtime between deployments, junior personnel are often sent to VAW-77 to gain experience and flight hours.

Source: Combat Aircraft Monthly, July 2010, Vol. 11, No. 7. "Drug Busting Night Wolves" by Ted Carlson, p26-31. 

DC-X, the Delta Clipper

One of the holy grails of aerospace technology not yet achieved has been true reusable single stage-to-orbit (SSTO) capability- a launch vehicle that is fully reusable and completely able to reach orbit in a single structure and return to Earth for reuse. No hardware or components would be shed on the ascent (or descent, for that matter). Some approaches to SSTO have looked at air-breathing vehicles while the other approaches using rocket power face the challenge of having a high enough propellant to mass ratio to reach orbit while still carrying a useful payload.

In 1989, three diverse individuals pooled their talents to pitch a rocket-powered SSTO vehicle to Vice-President Dan Quayle. Max Hunter began his work in aerospace engineering with Douglas Aircraft, having become their chief engineer for astronautics after heading the Thor IRBM program. He later came to Lockheed to work on various aspects of the Strategic Defense Initiative (SDI). Retired Army general Daniel Graham had a background in intelligence and was one of the biggest proponents of the SDI program in the Reagan Administration. And the third individual was Jerry Pournelle, a noted science fiction author, journalist, and, like Graham, a proponent of SDI. The three men met with Quayle that year to pitch their SSTO idea as a means of lowering the cost of access to space, a necessary requirement to make SDI feasible.

With Quayle's backing and funding from the SDIO (Strategic Defense Initiative Organization), in August 1990 a request for proposals to industry was issued for an SSTO vehicle. Of the six designs submitted, four were vertical takeoff and landing designs. SDIO issued $12 million contracts to McDonnell Douglas, Rockwell, Boeing and General Dynamics for further development of their VTOL SSTO designs. The second phase of the program consisted of building an "X" subscale demonstrator to prove VTOL capability and the building of a "Y" prototype vehicle. McDonnell Douglas won this phase of the competition with their "X" subscale demonstrator being 1/3 of the size of the prototype and designated DC-X or "Delta Clipper".

Powered by four Pratt and Whitney RL10 liquid fuel rocket engines, the DC-X wasn't meant to reach orbit but to validate the technologies for VTOL, rapid prototyping, and the ability to be operated with as small a ground crew as possible to reduce costs. On 18 August 1993 at White Sands Missile Range in New Mexico, the DC-X made its maiden flight with a support crew of seven (including astronaut Pete Conrad) housed in a converted trailer. The Delta Clipper flew for 59 seconds, reaching a very modest altitude of 46 meters. Later test flights going into 1995 showed the DC-X's ability to translate side to side and land, reaching a maximum altitude of 2500 meters before a hard landing on 7 July 1995 cracked the aeroshell of the Delta Clipper.

But with the end of the Cold War, SDIO's budget had been cut and the Delta Clipper was becoming a political hot potato in Washington. The program was then transferred to NASA's Reusable Launch Vehicle program. McDonnell Douglas took the opportunity to further lighten the DC-X, including a Russian-built aluminum-lithium liquid oxygen tank from Energia. With a significant weight reduction, the vehicle was redesignated DC-XA "Clipper Graham" in honor of Daniel Graham who had passed away in 1995. The DC-XA returned to White Sands for its resumed test program and made four flights in the summer of 1996. Between the second and third flights, the rocket was turned around in only 26 hours, a first for any rocket vehicle in history. On the fourth flight, one of the landing legs failed to deploy and the DC-XA tipped over and was destroyed in a fire.

NASA refused to release money to repair the DC-XA as it preferred from the beginning its own reusable SSTO idea, the Lockheed X-33 VentureStar. However, the VentureStar program was cancelled in 2001 amidst technical difficulties, but the DC-X may yet have the last laugh. Many of the DC-X engineers are now working with commercial space startup Blue Origin, started and led by Amazon.com founder Jeff Bezos. Blue Origin's spacecraft design, New Shepard, was tested in subscale format for the first time successfully in November 2006.

Source: Air & Space Smithsonian, August 2010, Vol. 25, No. 3. "Black Day at White Sands" by Preston Lerner, p66.

The First Russian Jet Bomber

Starting in January 1947 OKB Tupolev began design work on a twin jet tactical bomber powered by two Rolls-Royce Nene centrifugal-flow turbojets. With a few months of the start of the work, it became apparent that the Nene engines produced less thrust than anticipated which delayed development work. Although this jet bomber design carried the official designation Tu-14, it had the Tupolev in-house designation of "73", a continuation of the ANT number series that was discontinued as the official designation during the Second World War. The Politburo wanted the Tu-14 ready for the annual Aviation Day flypast at Moscow-Tushino. But the need to redesign the Tu-14 meant that the prototype would not be ready and Andrei Tupolev himself suggested re-engining a number of piston radial-powered Tu-2 bombers with Nene engines as a temporary measure.

The interim project was given the OKB designation "77" (ANT-77) but would have the official designation Tu-12. Work began in April 1947 even before an official decision was reached authorizing the Tu-12/"77" project. By May of that year the Soviet Air Force reviewed Tupolev's full-scale mockup. Even before the Air Force review of the mockup, Tupolev ordered work to begin in the OKB's workshops converting standard Tu-2S bombers to the Nene-powered configuration. At the end of the month the Air Force authorized conversion work to begin based on their mockup review.

For the sake of expediency, the changes to the Tu-2 bomber were kept to as few as possible. The main differences between the Tu-12 and the Tu-2 were as follows:

• The Shvetsov ASh-82FN radial engines and nacelles were replaced by longer nacelles housing the Rolls-Royce Nene turbojets. 
• The wing dihedral was reduced from 6 degress to 3 degrees.
• The fuselage was stretched with a nose extension allowing the bombardier/navigator to sit ahead of the pilot and a rear fuselage stretch to balance the change in the cockpit.  The height of the midfuselage was increased with the top of the pilot's cockpit even with the top of the aft gunner's canopy. 
• A tricycle undercarriage was fitted with the mainwheels rotating 90 degrees to lie flat at the bottom of the nacelles. 
• Additional fuel tanks were added to compensate for the increased fuel consumption of the jet engines. 
• Adjustments were made to the control system to compensate for higher speeds. 
• The tail structure was reinforced as well to handle the increase in speeds. 

In July 1947 the prototype Tu-12/"77" was rolled out and on 27 July 1947 the first flight was made in the Soviet Union of a pure jet bomber with none other than Andrei Tupolev himself aboard for the maiden flight- to which he exclaimed "Well, now we've seen for ourselves that youc an fly without an airscrew!" After a handful of successful test flights, the Tu-12 participated in the Aviation Day flypast at Moscow-Tushino and then resumed its flight test program in September of that year. The aircraft was then handed over to the Soviet Air Force to begin state acceptance trials and even though the Tu-12 was only an interim type built from converted Tu-2 bombers, it gave both Tupolev and the Soviet Air Force valuable experience in operating jet bombers. Mock combat sessions were even conducted between the small batch of Tu-12s and the MiG-9 and Yak-23 jet fighters, allowing new tactics to be devised.

Six Tu-12s were made by converting Tu-2s. One aircraft was used as an engine testbed, another was used as part of jet drone development and the remaining four were used by the Soviet Air Force for crew training and familiarization for aircrews bound for the definitive Tu-14. The experience in developing the systems for the first Soviet jet bomber would serve Tupolev well during the development of the Tu-16 "Badger" and Tu-95 "Bear" bombers.

Source: OKB Tupolev: A History of the Design Bureau and its Aircraft by Yefim Gordon and Vladimir Rigmant. Midland/Ian Allan Publishing, 2006, p117-121.

The Droopsnoot Lightning

One of the more unusual experiments in bombing tactics by the Allies in the Second World War was the Lockheed P-38 Droopsnoot version of the Lightning twin-engine fighter. The idea behind Droopsnoot was that a bombardier-equipped P-38 acting as a formation leader for standard P-38s carrying bombs could carry out missions on smaller targets with an economy that reserved the heavy bombers for larger targets. A formation of P-38s was seen as less likely to draw the attention of the German air defenses that were on the lookout for heavy bomber formations and the performance of the P-38 as a fighter made it "self-defending".

In 1944 the Eighth and Fifteenth Air Forces in England modified a number of P-38 Lightnings into Droopsnoots. The usual modification involved removal of the guns and the replacement of the nose cone with a Plexiglass nose piece with a flat window for aiming a Norden bombsight. Additional windows were added to the sides of the nose to provide light for the bombardier who entered via a hatch on top of the nose but also had an escape hatch on the ventral side as well. The bombardier also had panels for arming the bombs as well as flight instruments and an interphone connection to the pilot. Provisions for oxygen and heating were also installed in the Droopsnoot nose.

Most Droopsnoot missions were carried out between 10,000 to 20,000 feet with a formation of standard Lightnings dropping their bombs on command by the Droopsnoot's bombardier who would call out a 10-second pre-release countdown. Some missions were even flown with the standard Lightning's bomb release switches hooked to the VHF radio equipment to allow the Droopsnoot bombardier to drop all the bombs in the formation by radio command.

By 1945, the Eighth Air Force's initial enthusiasm for the Droopsnoot dampened following operational experience. P-38 pilots weren't trained in tight formation keeping like bomber pilots were and less-than-optimal formation flying led to dispersion of the formation's bomb load, lessening the destructiveness on small targets. It was also found that the Droopsnoot missions were no substitute for individual ground attack aircraft making shallow to medium dive angle attacks on ground targets. After the first Droopsnoot missions were flown, the German air defenses were on the lookout for large formations of P-38s which acted differently than escort fighter formations and fighter sweep formations. Given that many of the Luftwaffe's fighters had been driven away from the coastal areas of continental Europe, most Droopsnoot missions encountered little air opposition, but those that were attacked by the Luftwaffe found that the lack of rear-facing armament was a disadvantage. Escort fighters ended up having to be assigned to Droopsnoot missions, rendering the "self-defending formation" argument irrelevant.

The final nail in the coffin for the Droopsnoot with the Eighth Air Force was an analysis showing that medium bombers like the B-25 Mitchell and B-26 Marauder could carry more bombs to the target than a Droopsnoot-led formation and better defend itself with the multiple gun positions on the medium bombers.

The Fifteenth Air Force was a bit more positive in their evaluation of the Droopsnoot missions. Targets were more closely selected for light flak and the formations were much smaller than the Eighth Air Force's formations with only 8 Lightnings being led by a Droopsnoot. Tactics were more along the lines of that used by the medium bomber force than the heavy bomber force, but that still didn't change the fact that, like the Eighth Air Force, the Droopsnoot missions still needed fighter escort and were actually less economical than a comparable mission flown with either B-25s or B-26s. The Droopsnoot Lightnings did find a niche with the Fifteenth Air Force as radar-equipped pathfinders (with a radar replacing the Norden bombsight) and weather reconnaissance aircraft dispatched ahead of heavy bomber missions to scout out the weather over the planned targets. In the summer of 1944, for instance, the Fifteenth Air Force used Droopsnoots as weather scouts over the oil refineries of Ploesti, Romania, before their attack by B-24 Liberators. The orbiting Droopsnoots relayed the positioning of German smokescreens so the attacking heavy bombers could adjust their inbound routes for maximum visibility of the targets.


Source: Lockheed P-38 Lightning (Warbird Tech Volume 2) by Frederick Johnsen. Specialty Press, 1996, p86-94.

The Boeing Model 306 Flying Wing Bomber

While Boeing was working on the XB-15 in the 1930s that would ultimately lead to the smaller but more advanced B-17 Flying Fortress and B-29 Superfortress, the company was engaged in a secret parallel project to develop a flying wing bomber that used some of the XB-15 features but was expected to exceed the performance of the XB-15 in every aspect. Boeing has never been previously associated with flying wing research with its current efforts in BWB (blended-wing-body) designs and the X-48 research program the legacy of the merger with McDonnell Douglas. Conventional wisdom of the day at Boeing regarded flying wings as less stable and having less than ideal handling issues than aircraft of conventional layout. Despite the prevailing attitudes of the company at the time, it did engage in flying wing research in 1935, developing a whole series of flying wing aircraft from the XB-15-derived flying bomber to fighters, airliners and even flying boats.

The Boeing Model 306 was the biggest and most impressive of the designs, aiming to capitalize on the aerodynamic advantages of the flying wing to improve upon the design work started with the XB-15. Having a crew of 10, the Model 306 had a swept wing of 140 feet in wingspan with a fuselage 60 feet in length. Four forward-mounted engines on the wings used 850-horsepower Allison V-1710 12-cylinder liquid cooled engines. Having a fully-retractable taildragger landing gear layout, the Model 306 bomber would have had a range of 5,000 miles with a 2,500 bomb load. Defensive armament consisted of a mix of 50-caliber and 30-caliber guns.

One of the more interesting features of the Model 306 had its elevons supported behind the wing trailing edge on long struts. Wind tunnel testing showed this arrangement more efficient as the pivoting and use of the elevons wouldn't interfere with the aerodynamic performance of the swept-wing.

It was only in 2006 that this series of designs came to light. It appears that all of the flying wing designs were collectively designated in-house as Model 306. Considering the state of the art in aircraft design in the 1930s, the Boeing Model 306 flying wing bomber stands out as quite futuristic!

Source: Secret Projects: Flying Wings and Tailless Aircraft by Bill Rose. Midland/Ian Allan Publishing, 2010, p71-71.

The Merger of Delta Air Lines and Chicago & Southern Airlines

When Chicago & Southern Airlines was acquired by Delta Air Lines in 1953, as far as airline mergers go, it was one of the more peaceful ones in terms of merging the labor forces. Much of that stemmed from both airlines having a similar work environment and the paternalistic attentions of Delta's founder and CEO, C.E. Woolman. He agreed that Delta would honor the existing labor contracts with the C&S employees after merger until which time those contracts were due to expire. Surprisingly, he left open the door for continued union representation considering that other than the pilots, Delta was non-unionized. However, as each former C&S contract came up for negotiation before expiration in the years following the merger of the two airlines, fomer C&S employees decided to forgo unionization and follow with the rest of the Delta labor force. Though the parent unions raised some protests, by and large the transition of the ex-C&S unionized workers to non-union proceeded remarkably smoothly.

The most important decision for Delta's management, though, was what to do with the flight engineers that came from Chicago & Southern. When the Civil Aeronautics Board mandated in 1948 that four-engined airliners needed a third member of the flight crew, Delta decided its flight engineers would be pilots and over the course of their careers would progress to first officer and then to captain. Like many of the airlines of the day, though, C&S promoted its flight engineers from the mechanic pool with no training as pilots. As such, C&S's flight engineers had no opportunity to advance to other flight crew positions.

This was a sticking point in the merging of the labor forces and C.E. Woolman was adamant that "We must never put a board on a man's head", thereby restricting the career advancement of the flight engineers that came from C&S. Woolman presciently saw that would lead to labor issues in the future.

As a result, Delta advised all of the former C&S flight engineers that while none would be fired, Delta's flight crews were reserved for employees with pilot training and certification. The Lockheed Constellations that belonged to C&S that were kept by Delta after the 1953 merger would still have C&S flight engineers, but they as a group were advised that once the Constellations were phased out, they would be guaranteed a ground position at equivalent pay. Those who did not accept the ground position offer were let go, but treated as if they had been fired, with one year's severance pay tax-free in accordance with Delta's policies of the day.

Most of the C&S flight engineers resigned and sought jobs at the other airlines that still used mechanics as flight engineers. But Woolman's decision proved wise as in the late 1950s and early 1960s labor strife broke out at the other US airlines which in some cases resulted in strikes, all of which Delta easily avoided.

Source: Delta: The History of an Airline by W. Davis Lewis and Wesley Phillips. University of Georgia Press, 1982, p236-237

Tupolev's Own Tristar Design

Amongst the Russian aircraft design bureaus (called OKBs), it's common practice to reuse designations for aircraft projects that have been previously used for aircraft that never made it past the design stage. The Tupolev Tu-204 twin jetliner, for example, is the third design to use the Tu-204 designation. Work on the first Tu-204 project began in 1973, at which time OKB Tupolev was studying the concept of a family of related aircraft designs that shared common features, powerplants and systems. At the time the Tu-134 and Tu-154 were the main domestic jetliners in the Aeroflot fleet as well as in the Soviet client states. The first Tu-204 project was for a short-haul transport carrying up to 180 passengers with two Kuznetsov NK-8 low-bypass turbofan engines (the same powerplant used on the Tu-154) mounted under a T-tail on the aft fuselage. In keeping with Tupolev's ideas for a family of related airliners, this first Tu-204 design would have shared many features of the Tu-134.

By the mid-1970s, though, the design bureau's work and moved towards a medium range airliner with comparable performance to the Airbus A300, the Lockheed L-1011 Tristar, and the McDonnell Douglas DC-10. The expected growth in air travel made a larger-capacity aircraft a more attractive proposition and efforts were made for this new, second Tu-204 project to embody many of the same cabin comforts of the Western wide-bodies. Work began in 1975 on this newer and larger Tu-204 project.

The second Tu-204 project would have had a large fuselage on par with that of the DC-10 and Tristar and underfuselage cargo holds that could accommodate LD-1 and LD-3 containers. A 28-degree sweptback wing with a supercritical airfoil combined with an extensive array of high-lift devices offered good field performance and efficient cruising speeds. A significant amount of time was spent on determining the ideal number of engines, location of the engines, and the type of engines to be used. Again returning to the idea of a family of airliners, Tupolev's designers created to variants of the Tu-204- a twin-engined version and a three-engined version. Both designs used the Soloviev D-30 turbofan (also used on the Il-76 airlifter). The trijet version had a longer fuselage and had its third engine mounted in the end of the aft fuselage and fed by a curved S-duct with its intake ahead of the vertical fin. For all intents and purposes, it strongly resembled the Lockheed Tristar.

Interestingly enough, in 1974 British charter operator Court Line flew one of its Tristars to Moscow along with cadre of Rolls-Royce engineers for a series of demonstrations for Aeroflot that took place over three days. While debatable about how serious Aeroflot's interest in the Tristar was, Aeroflot's engineers were given full access to the aircraft for close examination. This would have been just a year before the launch of the second Tu-204 project.

In the late 1970s the Soviet Council of Ministers issued a directive for a more comfortable and technologically-advanced jetliner that had efficiency as its key selling point. It had to be on par with what was seen as the most advanced jetliner of the day, the Boeing 757/767 series that were under development in the late 1970s (the 767's first flight was in 1981, the 757's was in 1982). As a result, in 1979, the Tu-204 family were redesigned with the more advanced Soloviev D-90 turbofan. Work on the two versions was done in parallel, but Tupolev's designers were steadily starting to favor the twin-engined design as the D-90 was showing promise and growth potential as a powerplant. By 1981 disputes emerged between differing design viewpoints at OKB Tupolev. One group felt that the twin-engined design was just as safe as the three-engined version and that design work should focus on a wide-body twin. Another group wanted to pursue the three-engined design for safety reasons and that the power of three engines offered more growth potential. And a third group emerged that favored a twin-engined design, but felt that the only way to match the 757/767's fuel economy was to use a narrow-body design.


In 1986 the third group won out the internal battle over the Tu-204's design. After a shuffling of design and engineering heads on the project, the Soviet Council of Ministers gave its approval for the Tu-204 to be a twin-jet narrow-body design that strongly resembled the Boeing 757 in layout. That marked the third use of the Tu-204 designation and that is the aircraft that made its first flight on 2 January 1989.


Source: OKB Tupolev: A History of the Design Bureau and Its Aircraft by Yefim Gordon and Vladimir Rigmant. Midland Publishing/Ian Allan, 2006, p267-273.

The Mikoyan I-320 Interceptor

One of the best aspects of being an avgeek comes when you find out about an aircraft you never knew even flew. I recently got the vastly upgraded edition of OKB Mikoyan and learned about the I-320 two-seat all-weather interceptor. From several different angles it looks a lot like the MiG-17 and it's clearly derived from that aircraft. In the late 1940s the Soviet Ministry of Defense issued a specification for a long-range interceptor- three bids were submitted from the OKBs of Lavochkin, Sukhoi, and Mikoyan. Late to the party but accepted for consideration was also a design from OKB Yakovlev. All of the designs were twin-jet aircraft.

Mikoyan's submission had the internal designation I-320/R-1 and it was designed and built in 1949- in tandem with the development of the famous MiG-15/17 family of jet fighters, accounting for its similarities in general layout. The main difference, however, was that the I-320 was a much larger and heavier aircraft with two crew and two engines. The engines were uniquely mounted in a stepped-tandem arrangement. The forward jet engine was mounted low in the forward fuselage with its exhaust semi-recessed underneath the fuselage just behind the cockpit. The aft engine was mounted in the aft fuselage just behind the wings much in the same way as the single engine of the MiG-15/17 with its exhaust at the end of the fuselage under the cruciform tail. The large nose intake had two splitters instead of the one intake splitter of the smaller MiG-15/17. The central portion of the nose intake fed the forward engine and the two lateral portions fed ducts that ran on each side of the cockpit to the aft engine.

The pilot and radar operator sat side-by-side under a broad cockpit canopy. This way both crew could scan the radar scopes and the radar operator had full dual controls and could relieve the pilot on long air patrols. The Toriy-A radar was mounted in a bullet-shaped projection above the nose intake and two 37mm cannons flanked the intake on each side of the nose.

Powered by two Klimov RD-45 engines of 5,000 lbs thrust, the I-320 was rolled out in April 1949 and made its first flight that month. Mikoyan's flight tests continued through 1950 and the aircraft was then delivered to the Soviet air defense forces, the PVO, for state acceptance and combat testing. The first version of the I-320, the R-1, didn't get accepted due to some stability issues at high speeds. Following the R-1 version in flight testing was the R-2 version which had more powerful Klimov VK-1 engines (the VK-1 was an upgraded and more reliable version of the earlier RD-45 engine used on the R-1 variant), aerodynamic refinements, and a third 37mm cannon mounted under the nose. With better performance in testing with the PVO, the R-2 got a more advanced Korshun radar to replace the earlier Toriy-A unit. During operational testing in 1951, a 37mm shell exploded in the feed belt and damaged the R-2's nose.

Mikoyan took the opportunity to try and rectify some of the stability issues dogging the I-320 as the R-2 was being repaired. As a result, it was redesignated as the R-3 version. The repaired and upgraded aircraft made its first flight on 31 March 1951 and it would make 60 flights during state acceptance trials for a total of nearly 46 flight hours. However, the I-320 never went into production as its performance was deemed inadequate. With the cancellation of Lavochkin's design, the La-200, and the crash of the Sukhoi entry, the Su-15 (the first use of the designation, not to be confused with the later and totally different Su-15 "Flagon" interceptor), Yakovlev's late entry won the competition and went into production as the Yak-25. For a while, though, Mikoyan retained the R-1 and the R-3 versions of the I-320 interceptor to develop instrument landing systems for the Soviet Air Force.

Source: OKB Mikoyan: A History of the Design Bureau and its Aircraft by Yefim Gordon and Dmitriy Komissarov. Midland Publishing, 2009, p127-130.

The Navy Diversion for the Son Tay Prison Raid

My blog posting yesterday about the Son Tay prison raid made mention of a Navy diversionary strike that allowed the raiders to sneak into North Vietnam nearly unopposed. One month before the Son Tay raid in November 1970, the main architects of the raid, Colonel Arthur "Bull" Simons and USAF Brigadier General Leroy Manor, visited Vice Admiral Frederic A. Bardshar. Admiral Bardshar was the commander of Task Force 77, the main aircraft carrier group of the Navy's Seventh Fleet and responsible for combat operations in Southeast Asia. Together the three men developed an ingenious deception plan to be carried out by Navy aircraft the night of the Son Tay raid.

President Lyndon B. Johnson declared a bombing halt on 31 October 1968 on all targets north of the 17th Parallel (the DMZ between North and South Vietnam). The purpose was two-fold, to tempt the North Vietnamese to the negotiating table at the peace talks in Paris and to help support the presidential campaign of Vice President Hubert Humphrey who was running against Richard Nixon in the 1968 elections. While neither plan worked for Johnson, Richard Nixon left the bombing halt in place as part of his plan to draw down US forces in Vietnam. By the time of the Son Tay raid in November 1970, a major Navy air strike had not taken place on North Vietnam (though there were numerous reconnaissance flights and reactionary attacks to protect those missions) for two years. With the Son Tay raiders entering North Vietnam via the "back door" through Laos, the US Navy's plan was to create as much havoc and panic amongst the North Vietnamese air defense system as possible to divert their attention to the east.

On the night of the raid, the three aircraft carriers Oriskany, Ranger, and Hancock launched a total of seven Grumman A-6 Intruders, twenty Vought A-7 Corsair IIs, eight McDonnell Douglas F-4 Phantom IIs, four Vought F-8 Crusaders, six ECM jamming aircraft and another fourteen support aircraft. The Crusaders and Phantoms were armed with air-to-air missiles to deal with any MiGs that rose up that night but the only offensive weapons carried by the rest of the Navy diversion force were AGM-45 Shrike anti-radar missiles. Instead of bombs, they also carried photoflash bombs and long-duration flares. The force crossed the beach "feet dry", creating a massive set of radar tracks that caused near-panic amongst the North Vietnamese as such a large force hadn't entered the area for two years.

This way, the Son Tay raiding force entering from Laos, were it to be detected that night, would have looked like a combat search-and-rescue force operating in support of what the North thought was a major strike against targets in the previously forbidden zone. Many of the Navy pilots found the mission bizzare but at the time of their preparations, launch, and execution of their vital mission, they were all on a "need to know basis" and it was only upon their return to the carriers of Task Force 77 in the Tonkin Gulf that they were informed of the role they played in supporting the Son Tay raid.

Source: Beyond Hell and Back: How American's Special Operations Forces Became the World's Greatest Fighting Unit by Dwight Jon Zimmerman and John D. Gresham. St. Martin's Griffin Press, 2007, p21-60.

Operation Kingpin: The Son Tay Prison Raid

Operation Kingpin, the raid on the Son Tay prison in North Vietnam, was the largest and most complex special operations mission of the Vietnam War. It would be a joint operation with the Army, Navy, and Air Force with 59 men led by the legendary Col. Arthur "Bull" Simons in the actual ground team that would enter Son Tay. One-hundred sixteen aircraft from the USAF and the US Navy participated, with the Navy aircraft flying from three aircraft carriers to conduct diversionary operations to allow the Son Tay raiders to sneak into North Vietnam from Laos.

On the night of 20 November 1970, the Kingpin force had departed RTAFB Takhli in Thailand just north of Bangkok. After a rendezvous over Laos for aerial refueling, the raiding force itself consisted of the following elements:

• Cherry 1: Lockheed C-130E (Raid force mission leader)
• Cherry 2: Lockheed C-130E (Mission leader for the Douglas A-1 Skyraiders flying close air support as Peach flight)
• Banana 1: Sikorsky HH-3E Jolly Green Giant (Assault team, they would intentionally crash land in Son Tay's courtyard)
• Apple 1, 2, and 3: Sikorsky HH-53 Super Jolly (Assault team)
• Apple 4 and 5: Sikorsky HH-53 Super Jolly (POW transport)
• Peach 1-5: Douglas A-1 Skyraider (Close air support)
• Falcon 1-10: McDonnell Douglas F-4 Phantom II (MiGCAP)
• Firebird 1-5: Republic F-105G Thunderchief (Wild Weasel SAM suppression)

In addition to the raiding force, a multitude of other tankers, early warning aircraft and Navy combat aircraft were assigned vital supporting roles to make Operation Kingpin possible. For at least a year up to the actual raid on Son Tay, the prison complex was a high-priority reconnaissance target imaged by both spy satellites and Lockheed SR-71 Blackbird flights as analysts and planners set about determining the forces defending Son Tay as well as the routines of the personnel and prisoners of the complex. Something as simple as laundry hanging out in the prison courtyard offered valuable clues. In the last few months before the raid took place, reconnaissance had shown that the North Vietnamese had added two SA-2 "Guideline" SAM battalions to the area. Each SAM battalion was self-contained with its own radars, command and control equipment and four SA-2 missile sites, each site with six launchers and 12 missiles. With two of these battalions in the area, that meant eight SAM sites would be defending the prison complex. And these SAM sites were often protected by a large number of mobile antiaircraft guns.

To meet this dangerous threat to the aircraft of the Kingpin raiding force, the 6010th Wild Weasel Squadron flying the SAM-site killing F-105G Thunderchief were added to the raiding force to knock out the missile sites. Firebird 1 through 3 would accompany the raiders all the way to Son Tay and orbit the area, knocking out the SAM sites as their radars went active. Firebird 4 and 5 were to act as spare aircraft in case anything happened to either Firebird 1, 2 or 3 during the mission.

As the assault teams hit the ground, the SAM site radars went active and the first of 18 SA-2 missiles were fired during the raid- but only two of them targeted (and missed) the helicopters, A-1 Skyraiders or the C-130s acting as mission command posts. The rest of those SAMs bored in on the F-105s of Firebird flight. Firebird 3 took a hit but was able to disengage and its crew were able to nurse the damaged aircraft to RTAFB Udorn in Thailand. As Firebird 3 disengaged, Captain Don Kilgus and his back seat electronic warfare officer (EWO, or "Bear"), Captain Clarence Lowery in Firebird 5 were called into action to duel with the SAM sites. One missile managed to detonate close to Firebird 5, but Capt. Kilgus felt their F-105G wasn't damaged seriously and he and his EWO pressed their attack, knocking out the site that had fired the offending missile.

Unbeknown to the raiders, the POWs at Son Tay had been moved the previous August to a new facility 12 miles away called Camp Faith. The POWs there were awakened by the sounds of the SAM launches trying to down the raiding force. Some weren't able to see out their barred windows but the prisoners on the west side of the building could see the flares, the SAM detonations in the sky, and the explosions by Peach flight's close air support strikes. Word spread amongst the POWs "They're raiding Son Tay!"

Disappointed having not found and rescued any POWs at Son Tay, the raiding force withdrew from the area in less than 26 minutes. Not a single man was killed and only two were wounded. The 59 men and their support aircraft had managed to kill 200-300 enemy troops.

As Firebird 5 withdrew with the rest of the F-105Gs from the raiding force, Capt. Kilgus realized their were losing fuel. And they were losing it fast. The near-miss by the SA-2 detonation had showered their aircraft with shrapnel and punctured nearly all the aircraft's fuel tanks. With the fuel loss too great to be offset by tanking from an orbiting KC-135, Kilgus and Lowery were forced to eject over the mountains of Laos. They had managed to eject near each other and met up on the ground and began to radio their location to await rescue. As it turned out, the nearest rescue helicopters to their position were two of the returning HH-53 Super Jollies from Son Tay, Apple 4 and Apple 5. After a midair refueling from C-130 Hercules tankers, the two helicopters diverted and plucked Kilgus and Lowery from the jungle, making them the only two pilots rescued in the Son Tay prison raid.

Dejected by their failure to rescue any POWs, what wasn't immediately apparent to the men of Operation Kingpin was that their historic raid scared the Hanoi government about the strength of the resolve of the United States when it came to the POWs. Within two days POWs that were scattered across camps in North Vietnam in small groups were crowded together at the infamous "Hanoi Hilton" where the lethal air defense umbrella around the capital would prevent any future rescue attempts. Prior to Son Tay, many POWs were in isolated groups and this isolation was used as a psychological weapon by their captors. With all the POWs now in one facility, the "Hanoi Hilton" was simply too crowded for isolation to be used and the morale of the prisoners skyrocketed as they were housed together in large groups, getting moral support from each other. The men from Camp Faith shared their stories of what they had seen that November night in the skies over Son Tay and all former POWs to this day mark their time in captivity by either "before Son Tay" and "after Son Tay".

Source: Beyond Hell and Back: How American's Special Operations Forces Became the World's Greatest Fighting Unit by Dwight Jon Zimmerman and John D. Gresham. St. Martin's Griffin Press, 2007, p21-60.

Lockheed's Contribution to the Space Shuttle Program

In the 1960s as preliminary design work began on what would become the Space Shuttle, thoughts turned to ways of protecting the vehicle on its fiery re-entry into the atmosphere. The thermal protection issue was closely intertwined with what structural material to use for the spacecraft. One school of thought was based on what was used on the X-15 program- a "hot structure" that was tolerant to high temperatures. Unfortunately this meant the use of expensive and possibly rare alloys. Since the X-15 was a smaller vehicle than what was planned for what would become the Shuttle, a hot structure made more sense. But a vehicle that was much bigger in size presented cost and materials challenges with the hot structure approach. Most of the design groups involved in the early planning preferred to use a conventional-alloy structure protected by a series of metallic shingles at first, but the weight of a reusable metallic thermal protection system was daunting, to say the least.

Lockheed had the necessary breakthrough that would allow the Shuttle to have a conventional-alloy structure but have a lightweight thermal protection system. Since the late 1950s Lockheed had been working on what it called a "reusable surface insulator" (RSI) made of ceramic compounds. By 1960 the company had applied for a patent on a material made of ceramic fibers. In 1962 Lockheed had created a ceramic electro-magnetically transparent radome 32 inches in diameter for the Apollo program, but the design changed and Lockheed's radome was never used in flight. However, the experience proved valuable for Lockheed which developed a special insulator that was made of a fibrous structure filled with the spaces filled with Plexiglass compound. They called it "Lockheat" and unlike the heatshields used on spacecraft of the day which were ablative (they charred to provide protection), Lockheat's material was called evaporative- the materials slowly evaporated, creating a protective gas layer. Different types of fibers were tested such as aluminum, silica, and born. Eventually by 1965 the company's Lockheat LI-1500 settled on silica fibers. It was light at only 15 lbs per cubic foot and was completely reusuable, being able to survive repeated heating past 2,500 degrees Fahrenheit. The Air Force flew a test sample in 1968 on a re-entry test vehicle and it passed with flying colors. LI-1500 is considered the progenitor of the Space Shuttle's current thermal protection tiles.

Lockheed continued to develop the silica-based RSI but they couldn't overcome the fact that it was very brittle. It couldn't cover an entire spacecraft, it had to be applied in small tiles calculated to be about 6 x 6 inches in size. With a small gap around each tile, the vehicle structure could deform slightly without compromising the integrity of thermal protection. Since the structure under tile even the small size of 36 square inches could still deform and crack it, the tile was bonded to a felt pad which in turn was bonded to the vehicle structure. A room-temperature vulcanizing adhesive was developed to affix the pad to the tile and the tile and pad to the spacecraft.

The silica-RSI tiles, though, weren't enough protection for the nose and wing leading edges for the proposed Shuttle Orbiter as those areas got even hotter than the tiles could tolerate. To solve this problem, the prime contractor of the Shuttle, North American Rockwell, turned to LTV (Ling-Temco-Vought) which had developed a reinforced carbon-carbon (RCC) material that was to be used on the cancelled X-20 Dyna Soar program. The RCC could easily heat up to 2,700 degrees F yet keep the spacecraft structure well below the 350 degrees F limit for aluminum. The black tiles were designed to protect up to 2,300 degrees F and white tiles were used to protect areas up to 1,200 degrees F. Those areas of the Orbiter that did not heat up past 750 degrees F were protected by a special blanket material called flexible reusable surface insulation, or FRSI.

As work continued on the Shuttle Orbiters in the mid-1970s, analysis found that stiff spots in the felt pads caused by gaps between the adhesive and the tiles and/or Orbiter structure could weaken the integrity of the tiles. NASA decided on what was called a "densification" process to strengthen the felt pads and a special silica slurry was created by DuPont that was applied to the back of the tile, baked for 2 hours, then waterproofed before being bonded to the felt pad.

But there was a problem. Columbia was nearing completion when the stiff spots in the felt pads were discovered and Columbia was due to be flown from Palmdale, California, to the Kennedy Space Center. Feeling that moving the Shuttle to the KSC was symbolic and important for program morale, Columbia was moved to KSC with 6,000 tiles missing and 24,000 already-installed tiles to be removed and modified. Not all the tiles had to be removed as it turned out, but each one already installed had to be tested for weakness. For 20 months, three shifts a day, six days per week, each tile was tested, removed and modified if necessary. The remaining 6,000 tiles still had to applied. This was March 1979 and by the end of November 1980 the tedious work was completed and further preparations could continue for Columbia's maiden flight on 12 April 1981.

Source: To Reach the High Frontier- A History of US Launch Vehicles, edited by Roger D. Launius and Dennis Jenkins. The University Press of Kentucky, 2002, p382-388.

De Havilland Canada and Australian Aviation Pioneer Bert Hinkler

De Havilland Canada had only been in operation for three years after having been established in Toronto in 1928 when the Australian aviation pioneer Bert Hinkler showed up at DHC's downtown offices unexpectedly. Not immediately recognized, Hinkler was already known in aviation circles as having conducted the first solo flight between the UK and Australia in a single engined Avro Avian biplane in only 15 days. Having served in the Royal Air Force in the First World War and worked as a test pilot for A.V. Roe (Avro), he was already known as an inventor and self-taught engineer having created several aircraft navigation instruments as well as a shell ejector for the back seat gunners of First World War observation aircraft. After having flown Britain's Schneider Cup racers he embarked on a series of increasingly long range flights that demonstrated his navigational skills.

When Hinkler showed up at DHC's offices in February 1931, he had just been on a several month tour in the United States visiting aircraft manufacturers looking for a suitable light aircraft that he could modify for a long distance flight he had secretly been planning. Not having found the ideal aircraft, he had come to Canada to examine the De Havilland Canada's DH.80A Puss Moth which was known for its high performance of the day with a top speed of 124 mph. A high wing monoplane derived from the successful Gypsy Moth biplane that DHC was already license-building for the North American market, terms were quickly agreed to and Hinkler purchased Puss Moth number 2049 with the Canadian registration CF-APK on 29 April 1931. As the aircraft was already completed, Hinkler wished to do his own modifications to the aircraft and DHC readily gave him access of their factory spaces at Downsview. Nearly every day, Hinkler would be in his overalls, tinkering and modifying his aircraft. Factory workers noted him to be a very polite and quiet individual who kept to himself most of the time other than the DHC engineers that offered him assistance with the various modifications he was carrying out on the Puss Moth. Much of his work centered around saving as much weight as possible, even to the extent of removing the navigation lights. The interior appointments were removed save the pilot's seat and replaced with a custom-made long-range fuel tank which was delivered from a firm in New York he had contracted with to build it to his specifications. Imported bracing wires which were streamlined in cross section were also delivered to replace the Puss Moth's original set.

Hinkler enlisted the help of two veteran engineers to figure out a way of replenishing the engine oil in flight but he wanted the system to be as easy to use as possible and to only replenish what was exactly needed. Discussing his dilemma by the water cooler, the DHC engineers pointed to the water cooler and decided that a similar system could be used in which in inverted can of oil fit into an adapter that fed oil the engine. So he wouldn't have to carry numerous empty cans in the cabin on his flight (he still hadn't revealed his plans), the engineers gave him a pair of tin snips to use to cut up the cans into pieces and throw them out the window.

He would take his aircraft out for a few test flights after each modification he performed. While most pilots who came to DHC's factory to visit often spent their weekends in the Toronto social scene, Hinkler would spend every weekend possible in New York. It later turned out he had courted and married a woman there, all while still being married to his first wife in England!

On 20 October 1931 he took off from DHC's Downsview airfield for the last time with no advance notice and landed in New York City to prepare for his record flight. Again, with no publicity and much secrecy, Hinkler departed New York the afternoon of 26 October. He planned his flight to take place in darkness and since he had removed the navigation lights from his Puss Moth, he wasn't allowed to fly at night over the United States. So he flew a long straight line flight over the Atlantic and Caribbean at night arriving in Kingston, Jamaica the next morning after 18 hours in the air. By Thanksgiving he had reached Natal, Brazil and prepared to cross the stormy South Atlantic. To keep the press at bay who had caught wind of his record flight, he filed a false flight plan to Dakar, Senegal, in West Africa and instead waited 48 hours before setting off and landing in British Gambia. From there he continued on to Casablanca, Morocco, then Paris, France, and finally landing in London, England where a hero's welcome awaited him, making Bert Hinkler the first person to cross the South Atlantic solo and only the second person to cross the Atlantic solo after Charles Lindbergh.

In 1933 he set out to break the existing UK-Australia flying time record which at the time stood at 8 days, 20 hours. He disappeared over the Alps and sevearal months passed before the wreckage of his plane and his body were discovered. The dictator Benito Mussolini ordered Hinkler buried with full military honors in Florence.

As an interesting aside I found this little tidbit:

A small piece of wood, a relic from one Hinkler's hand-made gliders, was presented to the U.S. astronaut Don Lind in early 1986 as a token of appreciation for his coming to Bundaberg to contribute to the Hinkler Memorial Lectures. Lind in turn gave it to Dick Scobee, the captain of the ill-fated final Challenger mission. Scobee took the wood with him on board the Challenger, inside a small plastic bag that he placed in his locker. After the explosion, the bag and the wood were recovered from the sea, identified, mounted, and later returned to the Hinkler Memorial Museum.


Source: The De Havilland Canada Story by Fred W. Hotson. Canav Books, 1999, p38-41.