Skydiving is scary. Skydiving from a hot air balloon with no forward movement from 13,000 feet is even scarier. Skydiving without a parachute is absolutely nuts. Finnish daredevil Antti Pendikainen jumped from a balloon after throwing his parachute to the wind. He then accelerated to over 100 miles per hour as he careened towards his death. Will his stunt team save him? You’ll have to watch to find out…
Labor Day is one of the busier travel days of the year. At DFW airport alone, over 170,000 people travel through the airport. It takes teamwork and coordination to make it happen. AP put together a beautiful time-lapse of a day at DFW airport with beautiful images and fascinating facts. It’s enough to make any avgeek’s heart swoon. In the video, there are plenty of MadDogs (MD-80s) along with a KLM A330, a Qantas A380 and a whole host of other aircraft.
This labor day, Avgeekery.com salutes the many men and women in aviation who sacrifice their holiday, so that so many others in our nation can enjoy time with family and friends.
SFO is one of the most unique airports in America both because of its local weather and its design. In good weather, the airport has some of the most unique simultaneous approaches and departures.
In less than ideal weather, delays are unfortunately very common. What makes SFO so unique? Let’s explore.
The Bay Area is blessed with a very temperate climate that makes for comfortable weather year-round. Yet the weather can also create chaos and do so quickly.
Have you ever looked out the window while landing at San Francisco International in good weather and noticed a plane flying seemingly in a close formation with you? There’s a reason for that. San Francisco International Airport has two sets of parallel runways.
On most days, traffic lands on runways 28L and 28R. These two runways are only 750 feet apart. The non-standard separation of the runways combined with the high volume of traffic at SFO along with noise abatement procedures has forced some creative and complex approaches into the airport.
During visual conditions, controllers are able to stagger the aircraft by assigning precise speeds at each waypoint of the visual approach augmented by navigational aids. This type of approach results in a relatively high flow of traffic of around 60 aircraft per hour(that keeps airline schedules running smoothly) and unique photos for Avgeeks.
When the low ceilings (or fog) roll in, get ready for flight delays at SFO
During less than visual conditions, the aircraft are spaced further apart laterally but still closer than standard separation at most airports. The airport utilizes what is known as a PRM approach or Precision Runway Monitoring combined with SOIA or Simultaneous Offset Instrument Approach.
A PRM approach is an approach that utilizes an additional radar controller to ensure separation. It is utilized at other major airports across the country to keep planes safe while flying closer together than standard on approaches during instrument conditions. SOIA is also employed at SFO to keep aircraft spaced further than 750 feet laterally until they are visual.
One aircraft on 28L flies the ILS (precision approach) and the aircraft on 28R flies an LDA or GPS which is slightly offset to the runway. (See approach plate here with myriad of notes). This unique approach does slow down the traffic flow to 38 aircraft per hour but keeps aircraft safely flowing into SFO during less than ideal weather conditions.
During really poor weather (like fog or low ceilings), SFO is restricted even further to just 30 aircraft per hour because arriving aircraft must approach the field in a single file line as they utilize the ILS (up to CAT-III) to land on 28R. Check out this guide if you are interested in learning more about SFO’s weather operations plan.
The next time you fly into SFO (even if delayed), thank the pilots for flawlessly executing a very complicated approach procedure to get you there safely.
Happy Independence Day weekend! As we get ready to celebrate America, it is good to celebrate those things that make America great. On 4 July, 1942 a special flying unit formed of Americans from our Greatest Generation was inaugurated to fight against Nazi oppression and ensure freedom for all. This legendary unit is none other than the men of the 332nd Fighter Group, most commonly known as the Tuskegee Airmen. Their heroics are not only due to their incredible record in combat against an armed enemy, but also because of their fight against inequality and right to equal opportunity for all Americans – it is said that they achieved a “Double Victory” through their perseverance, competence, and dedication.
Today, the Tuskegee Airmen Legacy continues through a multitude of organizations and activities, including the Commemorative Air Force Red Tail Squadron, Tuskegee Airmen, Inc. and several others, but I want to share with you one that I personally know and think we should support: the Legacy Flight Academy.
The Legacy Flight Academy (LFA) is an IRS 501(c)3 non-profit organization that’s dedicated to upholding and sustaining the Legacy of the Tuskegee Airmen. They support several youth aviation outreach and education activities throughout the year, but their primary activity is a 2-week summer program that is conducted at Moton Field in Tuskegee, AL. Students who participate in LFA literally walk in the footsteps of the famed Tuskegee Airmen as they learn character lessons from the example of all the men and women from the “Tuskegee Experiment” and receive hands-on flight training in preparation for their own aerospace careers. What’s neat about this program is that it’s impactful. Program attendees have gone on to do amazing things in aviation. It’s a perfect example of a program that builds a love of aviation in the hearts and minds of our nation’s youth.
Check back tomorrow for part 2 as we interview one of the founders of the Legacy Flight Academy. We’ll also profile a couple of the success stories.
Boeing broke the internet again with this amazing video!
Last year, Boeing released a video of the the Dreamliner that even dedicated avgeeks thought was computer generated. The flying was so aggressive and the footage was so stunning that people swore that it was fake. This year Boeing is back with another video. This time instead of a 787-8 it’s now the newer 787-9 model which is 20 feet longer and can fly 450 nautical miles further than it’s shorter -8 relative.
This year’s performance video is equally impressive. Once again, the video is shot utilizing drone footage and other aerial cameras. It is stunning and equally as aggressive as last year. The initial takeoff is stunning and the flight itself is masterfully executed. The video shot is actually just the rehearsal. The actual performance will take place at the Paris Air Show later this month.
Here’s a clip out of Travis Air Force Base, California that shows a timelapse of the engine start sequence for the Boeing C-17A Globemaster III. The C-17 is powered by four Pratt and Whitney F117-PW-100 engines. Normally, C-17 pilots start each engine off of the Auxiliary Power Unit (APU) in order from 1 to 4. This clip shows that “standard” start sequence, where the Pilot (left seat) starts numbers 1 and 2, and the Copilot (right seat) starts numbers 3 and 4. While this video is condensed to just 17 seconds, a normal start sequence can take about 30 minutes (from getting in the seat to ready to taxi), depending on the crew experience and exact method chosen to start the engines.
If you are interested in seeing more amazing C-17 videos by the creator of this video, check out C17Jamie on Instagram.
For the return to KDFW, I opted to sit in economy to get the full experience this airplane had to offer and get a good look at the wings and control devices on them. Even in economy, the 787 showed great improvements for passengers with cloth seats (cloth generally being softer and more forgiving on the behind during the long haul flights for which the 787 was intended), video screens in every seat, a roomy two cabin 3-3-3 configuration, and really generous recline. Large overhead bins provided room for even the most cumbersome carry-on bags (yes, Boeing addressed you Mary Poppins types out there).
As we settled in, the flight pushed back a bit late at 1228L. This time, sitting over the wing, I could clearly hear the start sequence as the boost pumps in the engines groaned to life vibrating the whole fuselage and awakening the beast. First, the port engine fired up, and then the starboard. The hydraulic system kicked in next, sounding not unlike the hydraulic system start-up of an Airbus (minus the barking sound addressed elsewhere in this fine website). The flaps and slats extended to the takeoff position (all carbon fiber), and we took our place in the usual queue of Chicago traffic. At approximately 1245L, we departed via runway 10L. Again, we climbed quickly through the weather and climbed only to flight level 280 due to turbulence reported at the higher altitudes. Right from the start this flight was not to travel as planned.
On this leg, I checked out the video system a bit more. If you’re a movie buff, then the AA 787 system is for you. I stopped counting after forty titles that included everything from old school favorites like Cool Hand Luke and Frank Sinatra flicks to recent releases like Interstellar. The GPS moving map feature performed at a level less than desired, as it could not be adjusted to show individual cities and towns you were passing over, as is available on American’s new Airbus in seat GPS products. The passenger seated next to me, a frequent flyer, spoke of the 787’s lower cabin altitude and how much of a difference it made on long haul flights. While not on American, he had flown the 787 to Europe on American’s competitor United (you can really thank Continental for those 787s at United), and noted he arrived feeling more refreshed and less dried out.
The GPS tool did come in handy when all of a sudden, my new friend discovered the time to destination had gone up by two hours! Sure enough weather in Oklahoma and the DFW area necessitated a diversion to Tulsa. While most passengers dreaded the thought, the avgeek in me became greatly excited at the prospect of yet another takeoff and landing in this fine airplane. Approximately twenty minutes later, the pilots brought ship 8AA down at Tulsa’s 18L.
Once we landed at Tulsa, we taxied to a remote parking spot to refile our flight plan and obtain the needed fuel. Our time on the ground lasted approximately an hour and a half, but again, the 787 proved comfortable for that time. We took the skies again at 1601L from 18L with a flight plan carrying us into the panhandle of TX and then down around the weather. The Captain did an excellent job of keeping us all informed. He had the flight attendants keep their seats for that flight given the potential for turbulence. Here again, the 787 shined. We encountered a bumpy ride, but the design of the 787 with its flexible wings dampened the turbulence considerably. Both plane and crew got us safely back to KDFW at roughly 1700L.
Once again, I went up and talked to the pilots (same crew as the morning), and they were so proud of the 787 and what it could do. This new family member proved its mettle carrying us back through the stormy skies of the heartland. All throughout the day, I could tell how much each employee from the flight attendants to the ground crews (who gathered in droves just to watch it park) really loved this airplane. Moreover, it was great to see American employees really in love with their industry again. Just as a newborn brings great joy to a family, it was plain (pun intended) to see that the 787 had rekindled the love of flying in all of us.
To the flying public, the Boeing 787 Dreamliner represents the future of aviation with composite materials, the most advanced avionics, and new levels of comfort for all passengers. Indeed, the 787 defines the cutting edge with these features, but to avgeeks such as myself, this new airplane is a new family member. My hometown airline, American Airlines, finally introduced this family member into service with much fanfare on May 7, 2015. Having grown up in DFW and being raised as an “AAvgeek” by American pilots in the neighborhood, I was eager to try this plane out and greet the newest member of our aviation family. While I could not fly on the inaugural service, this article documents travel on 9 May to KORD and back (one leg in business class and the other in economy) before this magnificent airplane begins service to its intended markets: Beijing, Buenos Aires, and Shanghai. Needless to say, the Dreamliner did not disappoint.
Although the first passenger service occurred two days earlier, the atmosphere of excitement surrounding the 787 had anything but faded. In fact, I met another avgeek doing the same exact trip as myself (the massive camera gave him away while my Boeing 787 T-shirt made me anything but inconspicuous). Passengers on the flight included everyone from regular passengers just trying to get on with their day to frequent fliers and even a few American marketing executives checking out the plane for themselves. Upon entering the aircraft, that new plane smell greeted my nostrils. The flight attendants, usually glum these days, beamed with enthusiasm and pride for this new aircraft, a symbol of the new American. Indeed, American’s new look proved both very comfortable and refreshing. I got to my seat, 2L, and began soaking in the whole airplane. The business class had two sections (one forward of the 2L and 2R doors, and one aft). Each section had 4 lie flat seats across in a herringbone pattern with every other row facing backwards. The much talked about dimming windows were all set to the dark setting preventing any light from entering.
Before long it was time for departure out of a cloudy DFW. We pushed on time at 0710L and engines started not long after. Given the relatively light fuel and cargo load for the short hop to O’Hare, the airplane eased forward onto taxiway Kilo with no spool up of the engines. We taxied to runway 17R, and at 0725L, the General Electric engines roared to life in a sweet symphony.
The aircraft lifted off quickly, the wings flexing as they bore the load of the airplane. Within a matter of minutes we reached our cruising altitude at flight level 410 and a speed of .88 mach or roughly 580 miles per hour. As advertised, the cabin remained quieter than older aircraft.
As we turned northeast towards Chicago, the flight attendants began preparing the inflight meal, leaving me some time to explore. Features of note included a standup bar between the two cabins, not yet stocked because of the brevity of these local familiarization flights, and a massive lavatory with a full size mirror (guess AA hopes you’ll dress up to fly the Dreamliner). Mood lighting was on full display in the dawn color scheme with soft reds and blues. With regard to the seating, the rear facing seats (according to myself and my fellow avgeek, non-scientific poll) offered the best exterior views as they were closer to the windows than the forward facing seats. Additionally, forward facing seats required the wear of a chest strap, akin to a car seatbelt, for takeoff and landing.
After approximately an hour and thirty five minutes, the Captain announced our descent into a cloudy and misty Chicago. To initiate the descent, the pilots had to not only pull the engines to idle, but also apply the speed brakes. Being such a smooth airplane, any sort of forward pitch caused the 787 to accelerate much more rapidly than older models. Coming down through the weather, we emerged about 1,000 ft AGL and landed smoothly on RWY 10C (formerly 10R). As we taxied to the gate, all eyes were on us, with some airport personnel stopping their cars to snap photos of the still new phenomenon that was AA 787 service.
Upon arrival at the gate, I was able to hop up and explore the real heart of the 787, its flight deck. The flight deck was a pilot’s dream with enough LCD screens to fill a sports bar. Without delving too much into the techy details, the 787 was without a doubt designed with pilots in mind. One tool in particular that impressed me was a radar that could show all vertical obstructions within 5 miles either side of the course and up to 1,200 miles away! All that being said, both pilots loved the airplane and were, like the flight attendants, beaming with pride.
Tomorrow, we’ll post a report by Alexander as he reports on his return from Chicago O’Hare to Dallas/Fort Worth International.
Do you have a trip report or interesting #avgeek story that you’d like to share? Send us a message on our Facebook page!
The 787 is already an #avgeek favorite. The sleek composite airplane might also become a favorite of Star Wars fans as well! ANA just unveiled that one of their latest 787s would feature a special paint scheme tied to the the much beloved Star Wars series. The aircraft features a stylized R2D2 motif with a large logo near the back 1/3 of the aircraft . The latest Star Wars movie will be released this December. No word on how long this aircraft will be painted in the special paint scheme.
A New York Times article was released this evening that raised the possibility that one of the pilots was locked out of the cockpit during a terrifying 8 1/2 minute descent. This fact raises the possibility that the crash was not caused by a catastrophic malfunction (like an explosive decompression) but instead could have been an intentional crash into terrain.
After 9/11, all airliner cockpit doors were required to be reinforced. Prior to 9/11, cockpit doors were weak and flimsy. The did not provide any protection in the event of a hijacking attempt. The upgraded doors that were installed after 9/11 could not be broken down by force. The upgraded doors also have a fairly advanced electronic security system to permit authorized access but prevent any unauthorized entry. The Airbus video below explains how the Airbus cockpit door is operated. Based on this Airbus instructional video posted on YouTube, it does appear to be possible to keep the door locked from inside the cockpit if the pilot at the controls was actively attempting to do so. While it is way too early to speculate on the exact cause, this latest information (if true) indicates that the cause of the crash could be much more sinister than mechanical.
Noted aviation historian Walter Boyne described Operation Ranch Hand as “a heart-rending example of how good airmen can be forced to do unpleasant work when it is determined that the war effort demands it.” There are few events in aviation history that evoke strong debates even to this day as those that surround the nine year use by the US military of the defoliant Agent Orange in Vietnam. The aerial spraying of herbicides was used initially in the United States for weed control but was on a strictly limited basis in the immediate post-war period. The first “military” use of aerial herbicide spraying came during the Communist insurgency in Malaysia during the 1950s when the British used it on a limited basis to keep communication lines through the jungle clear.
The British use of air-delivered defoliants was cited by by proponents in 1961 in the proposal presented for President Kennedy’s consideration. Supported by the Secretary of Defense, Robert McNamara, the requisite approvals were also secured from not just the President but also President Ngo Dinh Diem and the government of South Vietnam. Some in the administration had raised the issue that use of the defoliants might be considered chemical warfare, but McNamara felt that operational necessity to reduce Viet Cong ambushes and hideouts in South Vietnam made the risk worthwhile. On 3 November 1961 McNamara authorized the use of defoliants in South Vietnam to combat the Viet Cong ambushes on US and ARVN units.
The USAF already had a limited ability already present for the aerial spraying of defoliants as part of its public service work on mosquito-control projects in the southeastern United States. At the end of World War II, a Special Aerial Spray Flight (SASF) was established at Langley AFB in Virginia to undertake mosquito-control spraying.
Activated in 1961 for Operation Ranch Hand, the SASF received six Fairchild C-123 Providers for modification into aerial sprayers. Inside the cargo hold of the Provider would be a 1,000 gallon tank connected to spray equipment mounted on the wings that could deliver the herbicides. To the surprise of the commander of the SASF, he found no shortage of volunteer pilots to fly the first Ranch Hand missions despite the proviso that they would wear civilian clothes, fly unmarked aircraft, be on temporary duty to Vietnam for extended periods of time and if shot down and captured, would not be acknowledged as USAF personnel.
There were several different herbicide options, each differing in the proportions of different chemicals present in the mix. Each option was given a color code name. Some of the options available included Agent White, Agent Blue, Agent Purple, but the most widely used option would become infamous- Agent Orange.
Once the first six C-123 Providers were modified, they deployed to South Vietnam and arrived in-theater in January 1962. The aircraft fleet ebbed and flow with the war, peaking at 25 C-123s in 1969. Over 20 million gallons of Agent Orange would be sprayed over 6 million acres in South Vietnam. Unlike a lot of other military experiments in Vietnam that were failures, the use of Agent Orange did work in denying the Viet Cong jungle cover in strategic areas of the country.
After a significant decrease in the number of ambushes on US Army/ARVN units in the first year of use, Defense Secretary McNamara authorized an expansion of Operation Ranch Hand to include areas of the Ho Chi Minh Trail used to infiltrate supplies and personnel into South Vietnam, and more significantly, to use Agent Orange for the destruction crops in Viet Cong strongholds to try and limit their food supplies.
The Ranch Hand effort expanded significantly in 1962 as a result as the C-123s wore South Vietnamese Air Force markings (and later in the war, full USAF markings). In fact, the first US aircraft shot down in Vietnam was a Ranch Hand C-123 on 2 February 1962, killing all three crew.
The first protests by North Vietnam were echoed by the Soviet Union and China in 1961 but met with a muted response by other nations. But criticism grew both in the United States and abroad as the program was expanded in 1962 to include crop destruction as the Viet Cong had successfully blended into the local population and as a result, the crops of many “friendly” South Vietnamese were also destroyed. By 1965 scientists in the United States were protesting the use of Agent Orange and the banner was subsequently picked up by the media and the anti-war movement of the day.
Three years later, President Nguyen Van Thieu of South Vietnam felt that Operation Ranch Hand was counterproductive but his concerns were overridden by a 1969 report prepared by the American ambassador to South Vietnam with a committee he appointed that showed that the use of the three main herbicides, Agents Orange, Blue, and White, were not harmful. Ambassador Ellsworth Bunker’s report quite obviously had the opposite effect and further inflamed the controversy further. Finally, on 22 December 1970 Secretary of Defense Melvin Laird advised President Richard Nixon that any herbicide use should conform to delivery and use standards in place in the United States which effectively ended the use of Agent Orange in South Vietnam. The last Ranch Hand flight flew on 7 January 1971.
Since the end of Operation Ranch Hand, millions of dollars in claims have been paid out by the manufacturer of Agent Orange and the Veterans Administration for the deleterious health consequences of the widespread spraying of the herbicide for nine years. To this day health effects are still being seen in even in individuals a generation removed from those originally exposed to Agent Orange.
In fact, when the National Museum of the United States Air Force in Dayton, Ohio, was to put on display a C-123 Provider that had taken more battle damage than any other of its type, it was subject to a political and legal controversy by local environmentalists that resulted in the aircraft being sealed up for display despite the fact no traces of Agent Orange could be found in the airframe.
Source: Beyond the Wild Blue- A History of the United States Air Force, 1947-2007, Second Edition by Walter J. Boyne. Thomas Dunne Books/St. Martin’s Press, 2007, p157-159.
Similar in concept to the USSR’s shuttle-clone Buran, the US Space Shuttle went through many design iterations including a concept where jet engines could be attached to the space vehicle for ferry and/or powered approaches. The concept proved unfeasible and too costly. Avgeekery contributor JP Santiago tells us why.
As design work by various aerospace companies began on the Space Shuttle program in the late 1960s, it was a given that the Orbiter would have its own jet engines. Having its own air breathing engines offered three advantages- they would allow atmospheric flight testing much like any other aircraft was tested and pilots could practice landings in the run up to an orbital mission. The engines also facilitated ferry flights, repositioning the Orbiter amongst various facilities (landing, launch, overhaul, etc.). Having its own jet engine propulsion also gave the Orbiter cross range capability upon return from orbit. Some designers envisioned the Orbiter rendezvousing with a tanker for additional jet fuel. But in the ascent and in orbit, jet engines and fuel for those engines was dead weight that subtracted from potential payload. Even if designers went with an Orbiter design that was unpowered on its landing, the 1970 and 1971 design studies prominently featured a fully reusable two stage Space Shuttle with a big flyback booster that would have to have its own jet engines. Some of the designs for the flyback booster were massive with a need for as many as twelve jet engines. Soon the design of the flyback booster itself began to take on technical challenges that rivaled that of the Orbiter design itself. The weight of up to twelve jet engines and the necessary jet fuel cut into the payload of liquid hydrogen and liquid oxygen for the booster’s rocket engines. Many of the flyback booster designs would need approximately 150,000 lbs of jet fuel (for comparison, a Boeing 777-200ER has a fuel capacity of roughly 300,000 lbs). Consideration was then given to using liquid hydrogen as fuel for the jet engines which would cut out the need for jet fuel tanks. In June 1970, NASA issued contracts to GE to study the feasibility of using liquid hydrogen in the F101 engine being developed for the B-1 bomber. Pratt and Whitney also got a similar contract to study the use of liquid hydrogen fuel in the F401 engine, the planned naval derivative of the USAF’s F100 engine planned for the F-15 Eagle. Both companies showed that liquid hydrogen fueled jet engines saved about 2500 lbs of weight per jet engine compared to conventionally-fueled jet engines. The weight savings was modest at best.
At the same time these studies were going on on how to save weight with Orbiter and flyback booster-mounted jet engines, with NASA there was a group at the Flight Research Center at Edwards AFB where unpowered landings were routine for many high speed research aircraft going back to the X-1 (the X-15 program being the most recent one at the time) and the graduates of the co-located Aerospace Research Pilot School had as a requirement that students demonstrate proficiency in unpowered landings using the school’s Lockheed F-104 Starfighters which were throttled down to idle for the practice sessions. Even more demanding were the unpowered landings made by the lifting body program aircraft that lacked wings and derived their lift from their tubby fuselage designs. Regardless of what sort of aircraft was used, USAF test pilots and the NASA-FRC pilots used what was called “energy management” where they traded altitude for airspeed on the descent and used turns to bleed off speed in preparation for final approach. The first step in unpowered landings was the arrival at the “high key” which was high above the touchdown point. From the high key, a gradual 180 degree turn was made that allowed speed reduction and descent to the “low key” which was usually abeam the touchdown point. From the low key, the turn continued allowing more speed to bleed off and the descent to continue until lined up for final approach. If at any point the speed was excessive, speed brakes or gentle S-turns could be used to get down to the necessary airspeed. The lifting body pilots found that on final approach, diving at the runway touchdown point 15 degrees or more improved their accuracy as the speed improved the stability and the speedbrakes could be used to moderate the speed build up on final approach. An assessment by one of the experienced lifting body pilots in September 1970 showed that in 30 landings on a 10,000 foot runway from altitudes as high as 90,000 feet and speeds as high as Mach 2, the dispersion of the landing points was only 250 feet.
However, the astronaut office in Houston at the Manned Spaceflight Center headed by Deke Slayton felt that unpowered landings for the Orbiter were too risky. Slayton was concerned that the test pilots were more proficient at unpowered landings than his astronauts would be, especially if they were returning from a 7-10 day orbital mission. The astronauts’ views carried considerable weight for good reason and it took the USAF to swing the design work in favor of unpowered landings.
I had posted previously that the Space Shuttle program’s development phase was taking place during a period of budget austerity. One of the keys to navigating the budgetary climate of the day was to be sure to secure as much political support as possible since Congress determined the program budget. But in 1970 the program had some close calls, narrowly avoiding funding cuts in both the House and Senate. The Air Force offered to lend its support as it saw opportunity in the Shuttle program to launch heavy reconnaissance satellites. But NASA had baselined the Orbiter design at the time with a 25,000 lb payload to orbit. The USAF wanted to put its heavy reconnaissance satellites into polar orbit and the Orbiter needed a payload capacity of 40,000 lbs. That much payload weight into polar orbit (and unable to take advantage of the Earth’s rotation for additional boost) was equal to a 65,000 lb payload launched for the Kennedy Space Center. NASA informed the USAF that the payload had to be baselined at 25,000 lbs due to the weight of the jet engines and their fuel. But it was apparent from the Congressional battles that NASA needed a strong ally like the USAF, so the jet engines were dropped from the Orbiter design and that allowed the payload capacity to orbit to meet the USAF requirements.
The idea of onboard jet engines didn’t end, though. NASA shifted towards the idea of removable kit that could be used for flight testing, ferry flights, and for return from orbit if the payload wasn’t maxed out. This also coincided with the 1971-1972 time frame when the flyback booster was dropped as too much of a technical risk and the Space Shuttle began to look more like its final design- an Orbiter with an external tank and solid rocket boosters in what was called the TAOS configuration- Thrust Assisted Orbiter Shuttle. The significant weight savings by going to a TAOS configuration also helped cut development risk as there was a considerable amount of experience already with solid rocket boosters and large external tank structures to hold cryogenic fuels.
The test pilots at NASA-FRC persisted in their opinion that jet engines were completely unnecessary in the Orbiter design. They had their long experience of over 10,000 unpowered landings since the X-1 program as their proof, but the astronauts insisted that the Orbiter was a much bigger aircraft than many of the X-planes. Another round of tests then were held by NASA-FRC, this time using their B-52 Stratofortress carrier aircraft. Set up in a high drag configuration with the engines at idle, pilots successfully and accurately landed the B-52. NASA-FRC then got some lifting body pilots who had never flown anything as big as the B-52 and had them fly the bomber through a simulated unpowered landing using energy management. They were able to land successfully and when the same pilots were asked to land the B-52 using a conventional powered low angle approach, none of them were able to do so. The test pilots the FRC even brought into two United Airlines pilots to fly the B-52 in simulated unpowered landings and they had no issue doing so, reporting that such landings were much easier than conventional landings. The test pilots then followed up the B-52 tests with the same tests using NASA’s Convair 990 which could simulate the Orbiter aerodynamics on landing.
NASA finally got agreement to go to exclusively unpowered landings on return from orbit for the Shuttle Orbiter, but the jet engines still didn’t go away. At the time of Rockwell’s award in 1972, the Orbiter design featured two engines that deployed from the payload bay and two more engines that could be mounted on struts. Less than six months later, the Orbiter design dropped the internally mounted jet engines completely and they were to be mounted as a kit on the flat underside when needed for flight testing and ferry missions. It finally took the ferry range to kill the engines completely from the Orbiter design. The Orbiter was similar in size to a Douglas DC-9 but had twice the weight. It had a lot of drag since it wasn’t optimized for atmospheric flight and the delta wing was highly loaded. With five jet engines mounted in pods on the underside and tank of jet fuel in the payload bay, the Orbiter had a ferry range of only 500 miles. With Space Shuttle sites across the nation and contingency fields overseas, a 500 mile range was simply unacceptable. NASA looked at aerial refueling during ferry, but this added complexity to a design that was already experiencing cost overruns. In February 1974, NASA deleted the jet engine requirement completely. As a result, both for flight testing and ferry flights, the Orbiter would need a carrier aircraft, but fortunately that was a lot more straightforward a development process!
Interestingly in the Russian Buran Shuttle program, there was an aerodynamic test analog designed OK-GLI that made 25 atmospheric test flights with four Lyulka/Saturn AL-31 jet engines mounted in nacelles in the aft fuselage. A fuel tank sat in the payload bay. The AL-31 is the jet engine that is used on the Sukhoi Su-27 Flanker. Nine taxi tests and 25 test flights were made using the Buran analog from December 1984 to December 1989. The engines were used to takeoff and then were throttled back on the descent to landing. All of the flight testing took place at the Baikonur Cosmodrome. The operational Buran, however, would not have jet engines at all and the Antonov An-225 Myria was developed as the carrier aircraft to ferry the Buran orbiter.
JP Santiago is a proven #avgeek, artist, and an excellent writer. He regularly blogs on his site Tails Through Time. He also runs the aviation Facebook fan page The Chicken Works that showcases his artwork. We are honored to have him as a guest writer on our site.
If you are interested in writing for Avgeekery.com, please send us a message on our Facebook page.
