Tag Archives: air force

Name that Plane

I’ll say this, it’s not often I come across a plane from the post-war era that went into serial production for the Air Force that I don’t instantly recall.

Trimotor

About these ads

10 Comments

Filed under Air Force, planes

Interesting goings-on in the Georgia National Guard

We’re not big on bashing the National Guard*.  Many, many Guardsmen have stepped up and served overseas during the War on Terror – assuming the same risks as their active duty counterparts, and also having to deal with employers or self employment issues that us active types never had to worry about.

In Georgia, the governor just appointed a new State Adjutant. State Senator and former Air Force officer Jim Butterworth has jumped from Captain to Major General. It is something of a controversial move. We have no idea as to MG Butterworth’s qualifications or character. But suffice it to say, it is unusual.

But the appointment of state adjutants is one of the prerogatives of a state governor. Last year, we saw a chaplain nominated in another state.  And it should be noted that while each state adjutant is a Major General in the Guard, it is not an operational command, but more concerned with administration and policy.

Having said that, since the federal government is footing the bill for most of the operations and equipment, perhaps it is time for Congress to revisit the issue of qualifications for state adjutants.

*We’re not big on bashing the National Guard anymore. Like all active duty troops, I was required by tradition to refer to them as “the Nasty Guard” and sneer at them playing soldier.

5 Comments

Filed under Around the web

Inside Commando Solo

A couple years ago, Craig shared pics and a bit of history on the EC-130E Commando Solo II PSYOPS aircraft.

Used to broadcast propaganda via radio and television, the EC-130Es were retired in the mid-2000s, replaced by new airframes built on the updated C-130J airframe.

Today, The Aviationist blog has some rare pics from the inside of the new birds.

EC130J_5

Comments Off

Filed under Air Force

US KC-135 Plane Crash at Kyrgyzstan Air Base – Business Insider

The Kyrgyzstan emergencies ministry says a U.S. Boeing KC-135 Stratotanker, used to refuel military aircraft, has crashed near an American air base in the country.

The Associated Press reports the plane went down Friday afternoon about 100 miles west of the re-named U.S. air base now called the Transit Center at Manas.

Spencer Ackerman from Wired tweeted that three crew members were aboard the craft, but official confirmation through the Air Force has yet to be released.

via US KC-135 Plane Crash at Kyrgyzstan Air Base – Business Insider.

Wow. Rough week. The Air Force lost an MC-12, a civilian contract 747 crashed on take off, and now this.

Update: Now with footage of the wreckage at the crash scene. there’s not a lot of footage there, but little sign of a post crash fire, and the wide dispersal of the wreckage indicates either significant forward velocity upon impact, or possibly an in flight break up.

1 Comment

Filed under ARMY TRAINING

Now’s not the time for slash and burn

At least, not when it comes to active duty troop levels.

One of my frustrations when frequenting Milblogs with a naval or air centric theme is that in tough budget times, the authors and commentariat are quick to offer up ground forces on the budget alter. “Oh, put the bulk of ground forces in the reserves!”

Well, here’s the thing. In the almost seven decades since the end of World War II, we’ve found ourselves time and again involved in manpower intensive ground combat.

Recently, retired Admiral Gary Roughead and defense analyst Kori Schake published a paper from the Brookings institution recommending that, in effect, all the looming budget cuts in DoD should come from the Army, and that the Navy and Air Force should see their funding levels maintained.

First, thanks guys, for validating the suspicion many of us harbored that AirSea Battle wasn’t a doctrine, but political maneuvering to preserve Navy/Air Force budgets. One can hardly fault a former Chief of Naval Operations for being a tad proprietary when it comes to his service’s budget.*

But to wave your hands and pronounce that henceforth, wars will be high technology affairs with little or no need for manpower intensive operations is to ignore not just the last seven decades of history, but all of history.

Comes now Steve Metz and Douglas Lovelace, arguing that, like it or not, we still need ground troops.

It would be nice if the United States could simply opt out of all messy conflicts, but it cannot. Global connectivity means that conflict in any part of the world has cascading effects. These are most intense in neighboring states or regions as combatants, refugees, money, disorder, crime, and weapons flow back and forth, but in most cases will spread even further. The recent conflict in Libya shows this contagion effect, when there is no sustainable security following the defeat of an enemy regime. In the future, major conflicts anywhere will affect the global and American economies, increasing commodity prices, disrupting the supply of goods and services, and creating uncertainty. U.S. economic growth will depend, in part, on whether the global economy is generally stable or conflict-ridden. This will make it difficult or impossible for the United States to totally avoid major conflicts (although it does not mean the U.S. will intervene militarily in every major conflict). The profusion of global diasporas will also make it politically difficult to ignore major crises or conflicts.

Now, Metz and Lovelace are not unbiased, either. They work for the Army War College at the Strategic Studies Institute.  But they’re quite right that in spite of all our efforts to avoid messy operations on the ground, we seem to always end up there.

I’ll grant that one reason we tend to fight land wars is that in recent history, our naval power has been so overwhelming as to effectively preclude a naval war. And I do fully support the nation keeping a strong, forward naval presence throughout those areas of the world that hold our strategic interest. But the Navy has done poorly at managing the relatively strong support it has received. That’s not to say the Army has done much better, but before the Navy and the Air Force raid the Army’s budget, maybe they ought to consider which branch has born the brunt of the nation’s fighting for the past 70 years.

 

*We’d be a lot more sympathetic if his term as CNO hadn’t been such a goatrope in terms of shipbuilding.

6 Comments

Filed under Air Force, army, history, navy, Politics, war

AC-130W

Early on in the blog, we wrote about the development of the gunship, modified transport aircraft armed to provide fires to troops on the  ground. They’re very expensive aircraft (mostly because of their sophisticated sensor arrays) so there are only a relative handful in service.

The introduction of the C-27J in service had some folks hoping a “Gunship Lite” program could be developed to supplement (but not supplant) the current AC-130U.  For various reasons, including the cancellation of the entire C-27J program, that never came to pass.

But the need to bolster gunship numbers didn’t go away.  So the MC-130W “Dragon Spear”  was pressed into service. Originally intended to make up for losses in the special operations MC-130H community (clandestine delivery and retrieval of special operations forces), the MC-130W’s were in fact armed with sensors and weapons. A 30mm Bushmaster gun and ViperStrike missiles gave it a limited ability to attack enemy targets on the ground with great precision.

The armed mission was so pressing, the special operations mission was set aside, and last year, the “Dragon Spears” were redesignated AC-130W Stinger II.

http://www.af.mil/shared/media/photodb/photos/2012/09/120918-F-PB123-002.jpg

The Air Force hopes to add Hellfire missile capability within the next year.  I’ve heard they can (or soon will) use the GBU-39 Small Diameter Bomb, but haven’t seen confirmation of that.

If you look closely at the pic above (click to embiggenfy) you’ll note not only the 30mm gun on the port side, but also the pylon outboard of the engine. That’s where the Hellfires will mount. The small turret under the nose radome houses the infrared sensor/laser designator.

2 Comments

Filed under Air Force, ARMY TRAINING

Getting your money’s worth

In 1952, Boeing, using its own money, began development of a jet transport prototype. From its first flight in July 1954, Boeing knew it had a winner, and proceeded to develop two new aircraft based on this 367-80 design.

A larger, longer variant went on to become the world famous Boeing 707. But a smaller, shorter plane, very similar to the Dash Eighty, would also go on to a remarkable career.

In the mid-1950s, the Air Force Strategic Air Command was shedding its piston powered B-29, B-50, and B-36 fleet in favor of jet bombers such as the Boeing B-47, and B-52. As fantastic as those two jets were, they still needed in flight refueling to meet the range requirements to hold at risk targets deep inside the Soviet Union. Existing tanker aircraft, based on the B-29, and its cousin the B-50,* simply couldn’t provide enough fuel, nor fly fast enough, to fulfill the mission.

So it came to pass, in the mid 1950s, the Air Force, wanting a jet tanker for Strategic Air Command, held a competition to build one. And as we all know, the winner was… Lockheed? Yep. Lockheed. They had proposed a jet with a configuration similar to the later VC-10. But since it would take some time before Lockheed could get around to building any tankers, the Air Force gave an interim order to Boeing to build 28 tankers based on its Dash Eighty prototype. That order soon grew to 250 tankers. And pretty soon, the Air Force it would be silly to support two separate tanker fleets, and cancelled the Lockheed program. Boeing’s order book continued to grow, and in addition to tankers, “vanilla” transport versions without the refueling equipment were ordered.  The basic designation for the design was the C-135. Tanker variants were known as the KC-135 Stratotanker.  From 1957 to 1965, Boeing delivered 820 tanker and transport C-135 Stratolifter aircraft, the vast majority of them as KC-135A tankers.

http://www.vr-24.org/SquadronScrapbook/B52_KC135.jpg

Originally intended primarily to support the Strategic Air Command’s bombers, the KC-135A tanker fleet found itself more and more involved in supporting tactical aircraft in Vietnam. The F-105s and F-4s based in Thailand would have been unable to strike the heart of North Vietnam without the support of the Stratotankers. Since that time, the fleet has been deeply involved in virtually all use of tactical airpower, and increasingly has supported US Navy carrier operations, particularly the very long flights in Afghanistan and Iraq.

From first delivery to the early 1980s, the KC-135s underwent very few modifications.  That’s a testament to the basic soundness of the design. But engine design in those years lead to far more powerful engines, with much better fuel efficiency, and lower noise levels. As commercial 707s began to retire, some KC-135s assigned to the Air National Guard were re-egined with their surplus TF-33 turbofan engines. More powerful engines meant a shorter take off roll. More fuel efficiency meant more of the fuel onboard could be transferred to other aircraft.  These converted jets were known as KC-135E’s.

Fifty-six KC-135A’s were specially modified to support the SR-71A. Since the SR-71A uses a special fuel (JP-7) that normal jets can’t use, these modified tankers had to be able to segregate their own fuel from that intended for offload. Designated KC-135Qs, several tankers could be expected to support every operational SR-71 sortie.

Eventually, the remaining KC-135A fleet was re-engined with the CFM56 high bypass turbofan engine, essentially identical to what a modern civilian airliner would use. Twice as powerful as the original J57 engine, far more fuel efficient and much quieter, it has given the fleet much lower operational costs, lower maintenance requirements, and better available fuel offload.  With the new engines, they were redesignated KC-135R.  With the retirement of the SR-71, the KC-135Q’s were also re-engined, and designated KC-135T, and used alongside the “R” fleet.

Finally, from 1999 to 2002, the fleet, now down to about 365 jets, underwent a modernization program known as Pacer CRAG (Compass, Radios, Avionics, and GPS), which completely updated the flight deck to modern standards. With the new engines and flight deck, navigator position could be eliminated, and crew costs reduced, all while improving aircraft efficiency and reducing operating costs.

Today, the KC-135 still forms the backbone of the US tanker fleet.

Almost as soon as the first of the C-135 family entered service, the Air Force recognized that such a sound airplane could be used for other roles.

One of the very first “off label” uses was to remove the refueling boom at the rear of the jet, and replace the operator station with a battery of panoramic cameras. These RC-135As were used for photomapping and topographical survey.

They also spawned a bewildering array of modified C-135 airframes for a variety of specialized reconnaissance roles, most in the Signal Intelligence (SIGINT) and Electronic Intelligence (ELINT) missions.

The Air Force tends to give programs a two word code name, generally with the first word being the “umbrella” for a particular genre of programs, and the second one being a specific designator. For instance, virtually all programs that begin with “Pave” have to do with electro-optical and infrared sensors to improve night flying or targeting.

The two major programs that most recon and special mission C-135s fell under were “RIVET” and “COBRA.” RIVET was usually a SIGINT or ELINT program, while COBRA usually meant gathering intelligence on Soviet ballistic missile tests.

Several times, a single KC-135 or C-135 would be specially modified for a particular purpose, receiving both a new designation, and a new code name. One example would be the C-135B modified in 1960 to RC-135E RIVET AMBER, equipped with a special phased array radar to track ballistic missile warheads. With the stupendous cost of $35,000,000 for the radar alone, it was at that time probably the most expensive plane in the Air Force.   Only one was modified. After it was lost in an accident in 1969, it was not replaced.

Quite a few aircraft would see their original mission change, undergo further modification, and receive yet another new designation and code name. Keeping track of all the variants is beyond the scope of this post, but suffice to say that the number of variants has used up almost all the available letters for designations.

The major RC variant is the RC-135V/W RIVET Joint, used both for strategic and tactical SIGINT and ELINT. Even today, RIVET Joint supports the war in Afghanistan.

File:RC-135 Rivet Joint 2008.jpg

That doesn’t count the various EC-135 variants, most (but not all) of which served as airborne command posts. Per wiki:

  • EC-135A – KC-135A modified for airborne national command post role
  • EC-135B – C-135B modified with large nose for ARIA mission
  • EC-135C – purpose built C-135 variant for airborne command post role, “Looking Glass”
  • EC-135E – re-engined EC-135N
  • EC-135G – KC-135A modified for airborne national command post role
  • EC-135H – KC-135A modified for airborne national command post role, “Silk Purse”
  • EC-135J – KC-135B modified for airborne national command post role, “Nightwatch”
  • EC-135K – KC-135A modified for deployment control duties
  • EC-135L – KC-135A modified for radio relay and amplitude modulation dropout capability “Cover All”
  • EC-135N – ARIA aircraft with “Snoopy Nose”
  • EC-135J/P – KC-135A modified for airborne command post role, “Blue Eagle” and “Scope Light”
  • EC-135Y – NKC-135 reconfigured as C3 aircraft for Commander-in-Chief, United States Central Command

Then there are the “weather reconnaissance” WC-135s.  The only “weather” the WC-135C and WC-135W ever looked for were radioactive clouds produced by nuclear explosions. They use special air sampling equipment to retrieve particulate matter to analyze the results of foreign atomic testing (and they’re still in service).

Various C-135s permanently converted to specialized test aircraft were designated NKC-135s, most being one of a kind modifications.

Finally, there is the OC-135B. Under the Open Skies treaty, the US and other signatory nations (including Russia) have the right to conduct scheduled aerial reconnaissance missions over any other signatory nation on a reciprocal basis (that is, for each overflight we make, the Russians can overfly the US).  There are limits to the equipment used (any recon equipment an Open Sky plane uses must be made available to any other signatory nation).  The US operates two OC-135Bs, and maintains one in storage.

This doesn’t even count the several Air Force jets that actually used the Boeing 707 airframe, such as the E-3 Sentry AWACS, the E-8 JSTARS, or the E-6 Mercury TACAMO.

For well over half a century, the C-135 family has served the United States well, and current projections have it serving until, at a minimum, 2040.  I guess when it hits 80 years old, it will have earned its retirement.

*The B-50 was essentially a B-29 with the R-3350 engines replaced by the R-4360- a radial engine of 4,360 cubic inches of displacement. The other major piston powered tanker of the time, the KC-97, used the wings and powerplant of the B-50 with a new, much larger fuselage to form the C-97 transport, which was further modified to the KC-97 tanker.  The KC-97L would actually continue to serve for a long, long time, with the last one retired from the Texas Air National Guard in 1978.

7 Comments

Filed under Afghanistan, Air Force, history, planes

Leadership Lesson of the Day

While I enjoy poking fun at the Air Force as much as the next guy, the fact is, they are a military service, and they face many of the same leadership challenges that the other services struggle with.

While this post focuses on the cultural problems of the Air Force, I’d say the lessons, particularly regarding centralized execution, are universal across all services.

Doctrinally, each and every service preaches devolving authority to the lowest possible level.  Mission orders describe an end state that a subordinate must achieve, allowing him the flexibility and initiative to achieve that state by the best means.

But in fact, virtually no commander at any level is willing to grant his subordinates the true freedom to execute without micromanagement. No supervision (which is a good thing) but detailed micromanagement. And if you micromanage your troops, they’ll let you assume more and more responsibility for how things are done, and the outcome good or bad (and it’s usually bad).

I’m a “company guy.” I’m not a bold, outside the box thinker. I spent a lot of time reading and understanding doctrine and thoroughly bought into the concepts. I wasn’t going to be the guy that invented a new way of doing things. On the other hand, our Army had a couple centuries of experience, and had bothered to write down what worked  in the past, so I saw no sense in reinventing the wheel, or learning the hard way what someone else had already taken the time to write down as “ the right way, AND the Army way.”

But there is a difference between understanding doctrine, policy, management practices and  processes, and forgetting that those policies, practices and processes are merely tools to achieve a mission. Following them is not the mission itself.

8 Comments

Filed under Air Force

AC-130

A little 105mm to delouse a ridgeline.

Timber!

H/T: Weasel Zippers

4 Comments

Filed under Afghanistan, Air Force, army, ARMY TRAINING, Artillery

Fox One!

Interesting pic stolen from Theo Spark. Two F-15E “Beagles” from Alaska launching simultaneously. Now, that’s not too uncommon. What’s interesting is what they’re shooting. Rather than the AIM-120 AMRAAM, both missiles are the older, semi-active radar homing AIM-7.  “Fox One” is the brevity code for a radar guided missile launch, announced when the shot is taken.

I guess you gotta burn through the stocks eventually.

I’m curious how old the picture is. The Beagle entered service in the late 80s, and the AMRAAM entered service just after Desert Storm. I guess this could be a fairly old pic. Or fairly new. Who knows?

1 Comment

Filed under Air Force, planes

PHOTOS: The Air Force Boneyard – Business Insider

Air Force boneyards appeal to the child in us. The rows of rusted out planes look like old, forgotten toys, which a child could reach out and grab and lift into the air again.

The feeling is even stronger for airmen.

via PHOTOS: The Air Force Boneyard – Business Insider.

43 interesting pictures.

Comments Off

Filed under ARMY TRAINING

T-X Competition Moves Forward, Despite Funding Challenges

Amid a cloud of uncertainty over how the U.S. Air Force’s next-generation trainer jet program will be funded, the service will hold an Industry Day this week as competitors learn more about the aircraft’s requirements.

For three days starting Jan. 29, industry will descend on Wright Patterson Air Force Base in Ohio for a series of meetings with Air Force officials.

“It’s a program that needs to happen, and it is by no means clear how to fund it,” said Richard Aboulafia, an analyst with the Teal Group.

T-X Program Needs

Despite a push by the Air Force, acquisition funds for the T-X program were not included in the fiscal 2012 budget. Because the federal government is operating under a continuing resolution that leaves the budget at 2012 levels, the program will be unfunded as long as the continuing resolution is in effect. Senior Defense Department officials have made it clear they don’t know if or when the resolution will be replaced with a new budget.

The winner of the T-X competition will replace Northrop Grumman’s T-38 Talon, in use since 1959. “The T-38 needs a replacement system by sometime in the 2020s,” Aboulafia said, a deadline that means the replacement program needs to be up and running “by the end of this decade” at the latest.

via T-X Competition Moves Forward, Despite Funding Challenges | Defense News | defensenews.com.

The T-38 is easily one of the more successful aircraft designs around. In  an age when supersonic aircraft still had decidedly deadly handling characteristics, Jack Northrop designed on that was safe enough to be used as a trainer, cheap and easily maintainable enough to be bought in large numbers, and durable enough to be in use over 50 years later. In fact, the Air Force recently upgraded the jets in its fleet to the T-38C configuration. Aerodynamically, nothing has changed. Most of the changes were to update the avionics to better conform to what pilots will see when they move on to operational aircraft.

And that’s what will be the major issue in the replacement, the T-X program. There are any number of airframes and powerplant combinations out there that would be at least minimally acceptable. The issue will be designing and integrating a cockpit display that will ease the student’s transition into his future mount.

A student pilot will spend about 18-24 months learning to fly. A very large part of that training is not so much about the actual stick and rudder movements, but learning to use the instruments of the airplane to build situational awareness. Changing the instruments is very disorienting to the student, and relearning a new panel takes time. And in flying, time isn’t just money, it’s a LOT of money.

2 Comments

Filed under ARMY TRAINING

Saturday ‘Vark Blogging

There was a time, a generation ago, when Discovery Channel had interesting shows.

 

Forty-five years ago, when the F-111 was first introduced, it was one of two all-weather precision strike aircraft in the world, the other being the A-6. Of course, back then “precision strike” meant being able to simply find a target such as a bridge or power plant at night or in bad weather. The F-111 used a radar bomb delivery computer that was much more accurate than visual delivery, but the bombs themselves weren’t guided, and precision was something of a relative term.

Twenty years ago when this first aired, if you wanted to deliver laser guided bombs or other precision guided weapons, your choice of platform was pretty much either the F-111, the A-6, or one of the then new F-15E Strike Eagles. The F-117s would be busy elsewhere.

Today, with improvements in targeting pods, and the introduction of the GPS guided JDAM, just about everything with wings can be a precision strike aircraft.

2 Comments

Filed under Air Force, planes

The XC-142

Longtime readers know I’m not at all a fan of the Marine Corps MV-22 Osprey program. But most of my objections to the program center on its costs, not on the aircraft itself. Personally, I think it is a pretty neat bird. And I enjoy watching them fly by en route from MCAS Miramar to 29 Palms. But every time someone tells me how revolutionary it is, I feel a strong urge to remind them that it is hardly new concept.

Almost from the first time helicopters flew, engineers started tinkering with ways to combine the speed characteristics of an airplane with the vertical take off and landing of a helicopter. After all, the rotors that lift a helicopter look an awful lot like the propellers that move planes forward. Was there a way to use one set of blades for both jobs? Taking off and landing a propeller driven plane from a tail sitting position was tried, but was soon found to be impractical, mostly because the pilot would have to fly looking over his shoulder.

Pretty soon, the concept of rotating either the entire wing, or just the rotors, from the vertical to the horizontal was tested. A variety of test aircraft were designed, built and tested throughout the 1950s. Most were little more than test-beds to explore the concept of a convertible plane.

By 1959, enough experience had been gained with tilt-rotor and tilt-wing test beds that the DoD actually began to consider designing a plane that could eventually enter service. After a couple more years of effort, the Tri-Service Assault Transport Program began in 1961, with the Navy as the lead agency for DoD. Ling-Temco-Vought (LTV) in partnership with the  Hiller and Ryan companies, was awarded a contract to design and build a prototype tilt-wing transport that would have better range and speed than existing helicopters. 

The resulting aircraft, the XC-142A would be the closest a convertiplane would come to entering service until the MV-22 joined squadron service with the Marines 40 years later.

One interesting administrative note, the XC-142A was numbered in the regular tri-service designation system under the conventional transport series, and not in the convertible aircraft series. It really should have had a designation of XCV-XXX. One can only guess, but perhaps the program managers felt the XC-142A was so much more likely to be bought in numbers than previous aircraft, that it should not share a series of what had heretofore been strictly test beds. And, rather annoyingly for your author, the XC-142A does not appear to have even been given a nickname or popular name.

On a conventional helicopter, each blade of the rotor is independently articulated. That is, it changes its angle of attack, or pitch, continuously throughout its rotation around the hub, and does so independently from the other blades. At any given time, each blade of a rotor is at a different pitch. Conventional propellers, even though they have variable pitch, do not do this. Instead, all blades of a conventional propeller change pitch simultaneously, and maintain that pitch setting throughout their journey around the hub. Helicopter rotors use this articulation to tilt the rotor disc forward or backward or side to side to provide thrust in the desired direction of flight, in addition to providing the lift to keep the helicopter in the air. But this articulation is also rather complex. That’s why when you look at the hub of a helicopter rotor, there’s all sorts of fiddly bits.

Previous convertible planes had suffered from excessive vibration and complexity, and LTV was at pains to avoid this. And so they came up with a pretty simple solution.  By vastly overpowering the aircraft with four T64 turboprops, and using conventional propellers only slightly larger than normal, they had more than enough lifting force to meet the requirements. What was needed was a way of controlling the aircraft in hovering flight without adding the complexity of full articulation to the props.  Since the entire wing rotated, the ailerons, normally used to control roll, could be used instead to control yaw in hovering flight. The airflow from the propellers would be sufficient to make the ailerons effective. Roll control in the hover would be provided by differential clutching of the outboard propellers. Pitch control in the hover would be by means of a small horizontal rotor at the very tail of the aircraft. In conventional flight modes, conventional control surfaces would be used.

One additional layer of complexity (and thus weight and cost and maintenance) that could not be avoided was crosslinking all four engines to a common drive shaft.  Imagine the XC-142A in a hover. Should one of the engines fail, particularly an outboard engine, the loss of lift on one side would cause an uncontrollable roll and loss of the aircraft. The answer was to have all four engines driving a common shaft, so even if a quarter of the total power was lost, the thrust would still be delivered symmetrically.

Aside from the whole tilt-wing thing, the XC-142 was a fairly conventional transport design. A boxy fuselage with a split ramp at the rear, with tricycle landing gear, with main mounts retracting into blisters along the fuselage side. In fact, because its propellers weren’t too large, it could take off and land conventionally with no tilt to the wing at all.

This was a very ambitious program. Remember, when the contracts were signed, the UH-1, CH-46, and CH-47 were just being accepted for service.

http://www.voughtaircraft.com/heritage/1532_034.jpg

Right click, open in new tab to greatly embiggenfy.

Five aircraft were built, and put through their paces.

http://www.aerofiles.com/LTV-XC142.jpg

The aircraft actually flew quite well, and its performance met the required specifications. But several things conspired to keep the XC-142 as a historical curiosity, and not a long serving warhorse.

First, the cross-linked driveshaft was troublesome. It produced excessive vibration (like virtually all its predecessors) and was less than wholly reliable. Problems with the shafting would lead to hard landings and damaged aircraft. And excessive vibration in a testing environment could only be seen as a harbinger of frequent failure in any future service environment.

Secondly, the utility of what would inevitably be an expensive aircraft was questioned. An XC-142 might lift 30 troops 100 miles twice as fast as a helicopter, but if it cost more than twice as much to buy and operate, buying two helicopters suddenly looks a lot more appealing.

Third, just as the XC-142 began to fly, the US was becoming ever more deeply involved in Vietnam, and the bulk of defense spending was going to fund that war and the machines needed right then, not some time in the future.

One by one, the each of the services in the Tri-Service program dropped out. The remaining aircraft were transferred to NASA, who used them for testing until 1970, when the last survivor was transferred to the Air Force Museum.

It’s odd that I couldn’t find a single decent video of the TC-4C, a plane with almost 30 years of service, but was instantly able to find quite a bit of good footage of this also-ran.

—–

—–

Thanks to Jason Camlic, who inspired this post via a post of his on Facebook. I can’t figure a good way to link traffic to him, but he’s always a great source of ideas and interesting tidbits from the world of aviation.

2 Comments

Filed under history, planes

Sikorsky will Probably Win the Combat Rescue Helicopter Contract

Mostly because it looks like they’re the only ones submitting a bid. It’s been about 25 years since the HH-60G Pavehawk entered Air Force service. A variant of the UH-60 Blackhawk, the Pavehawk is designed to penetrate enemy territory to retrieve downed aircrews. As such, it’s the successor the the Jolly Greens of Vietnam War fame. And while Special Operatons aren’t its prime role, it has been tasked to do that from time to time as well. In recent years, Pavehawks have supplemented Army MEDEVAC helicopters in Afghanistan and Iraq by providing CASEVAC support.

HH60PaveHawk.png HH-60G Pave Hawk

HH-60G Pavehawk

The Pavehawk has a record to be proud of. But it is also getting old. Further, it has always been hampered by a relatively short range and endurance, and limited cabin space and lifting capacity. All the extras above a normal Blackhawk come directly out of its total lifting capacity.

For over a decade now, the Air Force has been searching for a replacement for its fleet of Pavehawks. Under a program known as CSAR-X (Combat Search and Rescue-Next) Boeing, Lockheed/EADS, and Sikorsky submitted bids. Boeing’s entry was based on the CH-47, Lockheed/EADS submitted a version of the VH-71 chosen for the Marine One program*, and Sikorsky entered a variant of their S-92 helicopter.

After a competition, Boeing’s entry of a modified CH-47 was selected. It was in fact to be a tailored version of the already in production MH-47G used by the Army for Special Operations.

But protests to the GAO and in court over the contracting process led to the contract being cancelled.

Three years down the road, the Air Force is still faced with the need to replace it’s Pavehawks. And so the Combat Rescue Helicopter competition has opened. But Boeing and Lockheed/EADS, having been burned once, aren’t going to play this time. Yes, the program is potentially quite lucrative, with plans for 112 airframes, and an eventual total of $15 billion in contracts. But despite the emphasis by the Chief of Staff of the Air Force, insisting CRH is a top priority, there’s a very good chance that austere budgets will see the program scaled back or even cancelled. And both Boeing and Lockheed/EADS have other, cheaper ways of keeping their baseline production going. Boeing will be building CH-47Fs and MH-47Gs for the Army for some time, and looks well placed to pick up some foreign sales as well. LMT/EADS will continue to partner for EH101 sales and manufacturing for European and other foreign markets.

So the only competitor left is Sikorsky and its S-92. So what is the S-92? So much of the basic S-70/H-60 Blackhawk design was just right, Sikorsky decided to leverage the basics into a larger, heavier helicopter. Mating a new fuselage to the rotor system and dynamic components of the Blackhawk produced a much roomier helicopter. The S-92 is in production for various government and civil operators around the world. About 130 have been built so far. The military variant has a ramp at the rear of the fuselage for ease of loading and unloading.

S-92 Warhawk

Now, the S-92 isn’t a bad helicopter.** But the arcane world of US defense procurement has made it such that a virtual off-the-shelf purchase of a proven design in which virtually all the difficult integration work for features such as Terrain Following Radar has been done, isn’t suitable. Any person with common sense would simply buy MH-47Gs, either from Boeing, or even from Army stocks. But layer upon layer of laws and regulation to prevent graft and reduce wasteful spending means that a five minute decision has instead lead to untold millions and a decade spent just getting to the point where the least desirable of the three initial entrants will likely be selected.

*The VH-71 is based on the EADS EH101 medium lift helicopter. The VH-71 program was plagued by poor management, shifting requirements after contract signing, and the resulting spiraling cost increases. Eventually that program was cancelled and the few “vanilla” airframes bought were sold to the Canadians.

**Well, there are apparently issues with the main gearbox. One requirement for FAA certification is that a gearbox has to be able to run for 30 minutes after a loss of oil pressure. But the S-92 got around this requirement by “proving” that loss of oil pressure in the gearbox was extremely unlikely. Since then, two S-92s have been lost to main gearbox oil pressure loss. Also, I’ve heard that the Canadian CH-148 Cyclone program has been something of a disaster.

Via War News Updates

2 Comments

Filed under Air Force

Speaking of Texans…

Aggie passed along word of a remarkable Texan who has left us recently.

Col. Ralph S. Parr Jr., 88, who was the only American pilot to receive both the Distinguished Service Cross and the Air Force Cross, passed away Dec. 7 at an assisted living facility in New Braunfels, Texas.
Joint Base San Antonio will honor the legacy of one of the Air Force’s most celebrated pilots and a former 12th Tactical Fighter Wing commander at a funeral service planned for 11:30 a.m. Monday in the JBSA-Randolph theater. Interment will follow the funeral service at 2 p.m. at Fort Sam Houston National Cemetery.
Parr was born in 1924 in Portsmouth, Va. He enlisted in the U.S. Army Reserve Nov. 4, 1942 and was accepted into the Aviation Cadet Program Feb. 2, 1943, earning his wings and a commission in the U.S. Army Air Forces Feb. 8, 1944. Parr was forced to retire in 1976 after sustaining a back injury while inspecting a roof for hurricane damage at Eglin Air Force Base, Fla.
During his career, he flew 641 combat missions with more than 6,000 hours and received more than 60 decorations, including a Silver Star, Bronze Star, 10 Distinguished Flying Crosses and 41 Air Medals.

He was an import, instead of a native, but from my experience, Texas is pretty welcoming that way.

And it is nice to see the Air Force giving a nod to someone who contributed so much to their heritage. The Air Force is a young service, and as such, traditions don’t stretch back centuries. Indeed, the Air Force can still reach out to veterans who were serving from Day One as an independent service. But the way to build strong traditions, is to start them.

Comments Off

Filed under ARMY TRAINING

Strafing Germany

April, 1945. The noose is closing upon Nazi Germany’s neck. In the East, the massive front of the Red Army is advancing upon Berlin. In the West, Great Britain, America, and France have breached the Western Wall, and leaped the Rhine. The 21st Army Group, the 12th Army Group, and the 6th Army Group are occupying the industrial heartland of The Reich. The Wehrmacht fights on, but for the first time, scraping together old men and young teens into ad hoc formations. But as fast as they can be formed, the Allied forces grind them up. For the first time, large numbers of troops begin to surrender, particularly in the West. The jig is up, and both sides know it is only a matter of time before the inevitable surrender comes to pass.

But for all the territory conquered , there are still  large swaths of Germany that have yet to feel the sting of war. No Allied soldier has trod their cobblestone lanes, nor yet has the mighty 8th Air Force sent its fleets of Fortresses and Liberators against the villages and towns that dot the countryside. To be sure, there are shortages of many items, and virtually every man of military age has been called to service. But otherwise, these places are as bucolic as a picture postcard.

The Army Air Forces, well aware that after World War I, many folks were convinced that the Imperial German Army treacherously quit before defeat, wanted to make the point across the entire German country that the Nazis had been well and truly beaten. The war had to be brought to every hamlet and burg.

The heavies of the 8th Air Force were still occupied plastering war production in cities. And so the task fell to the 9th Air Force. Long occupied with supporting the troops on on the ground, and interdicting transportation behind the lines, medium and light bombers, and fighters of the 9th were tasked in the closing days of the war to redouble their efforts. Every train, truck and barge had long been a target. Now, the Wings and Groups of the 9th would fan out across the countryside. In virtually every village, there was a Bahnhof *and Reichspost. With bomb, rocket and gun, the B-25s and B-26s, the A-26s and A-20s, and most importantly, the P-47s of the 9th would lay waste to the most prominent local symbol of the German government. After this war, there could be no doubt that the German forces had been well and truly defeated. Every citizen would feel at least a little pain.

And of course, every strafing run was caught on gun- camera film. Here’s a remarkable collection of footage from one fighter group, the 362nd, in April 1945.  It starts with hand held camera footage of surrendered German troops. While most of the German Army fought until the bitter end, large numbers decided surrender was the wiser course of action. Amazingly, such was their level of unit cohesion that it was usually left to the German formation to move itself to collection points for disarming and internment. That’s why you see German soldiers still under arms.

Grab a cup of coffee, as this runs about 30 minutes.

*train station

Comments Off

Filed under Air Force, history, planes

Camp Bastion and other morning news.

Roamy expressed some frustration that she couldn’t find a lot of articles on the attack on Camp Bastion. Well, the papers have started to catch up.  I can’t think of a time since Vietnam when the US lost 6 planes on the ramp. Here’s a little more detail on the attack:

www.reuters.com1

Click to embiggen. It’s a big graphic.

Here’s an article at Long Wars Journal that gets into some detail.

The Marines have a long history of fighting to defend the perimeter of an airfield. In fact, exactly 70 years ago, the 1st Marine Division was ashore on Guadalcanal, fighting to hold onto Henderson field. And more than just small infiltration teams faced them. As of September 1942, the forces on the island were roughly equal. And the IJN would send heavy cruisers and battleships to blast Henderson Field repeatedly in the course of one of the closest run campaigns of the war.  So while the loss of two Marines, and 6 jets hurts, it’s not going to mean the end of operations there. 

……

China unviels yet another stealthy fighter.

Mind you, building one prototype doesn’t a fleet of fighters make. The prototype of the F-22 flew on 29 September, 1990. It would be another 15 years before it became operational.  Still, Mitt Romney’s plan to reopen F-22 production sounds pretty good to me, even with an estimated $1bn in startup costs.

…..

The WaPo has an interesting article on the B61 bomb and the costs of maintaining the nuclear inventory. Of course, since there is zero political support for developing new weapons, the old ones will have to soldier on, and that means increasingly expensive support.

The B61 is the backbone of “bombs” (as opposed to missile warheads) in our arsenal.  The primary delivery platform is the B-2 bomber. There was a time not too long ago, however, that if you flew fast jets, you qualified for and trained for a nuclear delivery mission. Today? I doubt more than a handful of tactical air pilots in  any service have ever flown a nuclear strike profile.  Maybe a few guys in the F-15E community. Dunno. It’s not something the Air Force spends a lot of time talking about these days.

…..

All sorts of good stuff like this over at War News Updates.

1 Comment

Filed under ARMY TRAINING

American MiG

We wrote about Constant Peg a while back, and mentioned Have Donut/Have Drill in that post.

Both programs were pretty much classified up the wazoo, but knowing about the capabilities of enemy airplanes is only really useful if it gets down to the warfighter’s level. Accordingly, classified training films of the evaluations were made and shown to select crews.

Oddly, the MiG-21 was flown under the cover name of “YF-110” which was the Air Force designation for the F-4 Phantom before the 1962 tri-service designation revamp. The Phantom, of course, would be the MiG-21’s primary opponent in the skies above North Vietnam.

You may also recall I posted a video a couple weeks ago about the operational evaluation of the Phantom in the hands of Tactical Air Command. One thing that very plainly struck me was that the entire film focused on the air-to-ground capabilities of the Phantom. TAC saw itself almost entirely devoted to air-to-ground missions. In spite of all their fighter pilot swagger, TAC left the business of serious thought regarding air-to-air combat to the Air Defense Command folks. But ADC faced an very different challenge than the TAC folks. It’s one thing to intercept a TU-95 Bear hundreds of miles away. Swirling around with nimble MiGs over their own territory while you’re trying to bomb the suburbs of Hanoi is an entirely different kettle of fish. And given the emphasis on using the missile armament of Sparrows and Sidewinders, neither of which liked to be fired from a wildly maneuvering jet, the air-to-air skills of the TAC had atrophied to a disastrous state. Where the US shot down about 10 MiGs in Korea for every Sabre they lost, the USAF in the early years of Vietnam saw Phantoms with only a 2-1 kill ratio, and at times, losses among all jets were as bad as 1 to 1.

Restrictive Rules of Engagement also squandered much of the Phantom’s advantages over Vietnamese MiGs.* The best way to shoot down a MiG is to bomb it on the ground. But fears of killing Russian advisors in bombing raids kept North Vietnamese MiG airfields off the target list for long stretches of time, and even when strikes were permitted, they were only allowed in fits and starts, not sufficient to keep the fields closed for more than brief periods.

The dismal performance of the Phantom in the air-to-air regime led the Navy and the Air Force to do a lot of soul searching. AIMVAL/ACEVAL, The Ault Report, Navy Fighter Weapons School (TOPGUN) and later Red Flag were all results the the services tackling head on their earlier failures. Technical improvements to both the Sparrow and Sidewinder greatly improved their performance. More importantly, tough realistic training greatly improved the aircrews ability to fight MiGs and win.

The MiG-21 was designed as a point defense interceptor, optimized for shooting down bomb-laden strike aircraft. It was fast as  a thief. It could also turn on a dime… for a little while**. While its delta-wing planform gave it great initial turning capability, it also had enormous induced drag, causing it to bleed airspeed in a turn like a hemophiliac. And in air combat, speed is life. The Phantom wasn’t nearly as nimble a turning jet. What it did have, however, was two great big thundering J79 engines that gave it a very good ability to sustain its energy levels through a fight. A ham fisted pilot would find himself out of airspeed, altitude and ideas very quickly, but a well trained stick-shaker could manage his energy level to outfly almost any opponent.

The whole point of maneuvering in air combat was to place your jet in optimum firing position, which in those days was very roughly a cone of about 30 degrees from the enemy fighter’s tail, and a range of about half a mile to 1-1/2 miles. Woe betide the Phantom pilot who tried to yank the stick hard enough to turn with the MiG. He’d find that very likely, the MiG would turn the tables, and find the gomer riding in his “saddle.” Instead, US pilots were taught to abandon this “angles” fight, and instead fight an “energy” fight. If you can’t out turn an MiG, how do you do this? By exploiting the vertical. Humans are essentially two-dimensional thinkers.  Most pilots, wanting to turn, instinctively turn in a level turn, parallel to the surface of the earth. As noted, this bleeds airspeed in a MiG. But a well trained Phantom pilot would make turns “out of plane1” A Phantom pilot that wants to execute a tight turn without bleeding a lot of energy would pull into the vertical. This would bleed airspeed, sure. But it would also quickly gain altitude. At the apex of the zoom climb, the Phantom at low speed could quickly tip its nose back earthward, execute a roll (with the practical effect of very rapidly changing its compass heading) and begin pulling out of the dive. And all that altitude is quickly converted back into a high airspeed, leaving the Phantom with reserves of energy to either kill the MiG, escape combat, or make further maneuvers.

Various other maneuvers, such as the “barrel roll attack” or the “lag displacement roll2” capitalized on the Phantom’s strengths, and minimized its weaknesses.  The “high yo-yo” allowed Phantoms to exploit energy for angles, and the “low yo-yo” allowed Phantoms to generate energy or range/angle offsets as appropriate.

With improvement in weapons, and the vastly improved training of aircrews, by the time of Linebacker I in 1972, the US Air Force and US Navy increased their kill ratio to an impressive 12-1. Through the lean years of the 1970s, and on through the early 1990s, both services placed great emphasis on supporting the training in air combat needed to ensure success. Today, while there is still strong support, the emphasis has shifted somewhat to integrating air combat into the strike warfare arena, and using new weapons and sensors to make traditional dogfighting less likely. Many traditionalists decry this, but the fact is, since Desert Storm, most US air-to-air kills have been Beyond Visual Range engagements with little or no dogfighting involved.

—–

*On the other hand, there were some very good reasons for some of the ROE restrictions. The big restriction was that pilots had to make a positive visual identification of their potential targets. That took away the range advantage of the Sparrow missile. But given the large numbers of US aircraft operating over North Vietnam, and the relative paucity of MiGs, without that restriction, the was a very great possibility of fratricide. There’s a good chance this rule saved more jets than it lost.

** The preferred MiG-21 tactic was to attack flights of F-105 bombers by coming up from behind and slightly below. Quickly accelerating to supersonic speeds, the MiG would dash in, fire off its Atoll heatseeking missiles, and dive away for safety. The Atoll was a virtual clone of the early Sidewinder missile.

1. The “plane” here isn’t the Phantom or the MiG, but rather the geometric concept of a plane, this one being the surface of the earth, which, yes, we know the surface is rounded, but for the purposes of aerial combat can be considered as a flat plane.

2. The Lag Displacement Roll lets a Phantom that is overshooting the MiG go outside the turn of the MiG, denying the MiG the opportunity to reverse its turn and attack. Instead of instinctively turning in the direction of the MiG, the Phantom barrel rolls away from the MiG and outside the track of the MiG’s turn. Once outside the MiG’s turn, the Phantom continues an in-plane turn with the MiG. It’s turn radius is larger than that of the MiG, but it’s turn rate matches well enough.  Essentially, the turn comes to resemble two well matched runners on a track, with one on the inside lane, and one on the outside lane. So while the Phantom may not have a shot, he’s not at risk of becoming defensive either.  Eventually, the MiG will bleed away so much energy that it can’t sustain the turn, allowing the Phantom to gain an angular advantage as well, and set up a shot.

5 Comments

Filed under ARMY TRAINING

Bird of Prey

(In which our resident Trekkie goes “Squeeeeee!!!!!!!)

About 20 years ago, Boeing wanted to gain insight into certain aspects of stealth technology and unconventional airframes, as it absorbed McDonnell Douglas, and moved into the tactical aircraft business. And the best way to do that was get a little hands on experience by building a technology demonstrator. That is, they built a one of a kind airplane, just because they could, and to see what happened.  The result was one of the more visually striking aircraft ever.

Even better, there’s video of it!

Looking at it, you’d think it was a hypersonic starplane, ready to blast its way straight to orbit. Actually, given the limitations on how it was constructed (hydraulic flight controls were used to save money) and the fact that stealth is stealth at whatever speed, the top speed was a very mild 260 knots, and the  max altitude was only 20,000 feet.

Boeing built and tested the Bird of Prey with its own money. As a private venture, it was never given an “X” number or any other government designation.  It was, however, donated to the Air Force museum after the test program was completed.

Total program cost? $67 million. And the experience gained has been used by Boeing on its X-45 unmanned aerial vehicle. 

(Later production variant is much larger, with sufficient space in the fuselage to accommodate two whales)

23 Comments

Filed under planes

MALD

Strike operations in the face of an integrated air defense system  IADS)are neither simple nor easy. Even for our Air Force and Navy/Marine Corps strike assets, with their liberal support from systems such as AWACS, dedicated Electronic Attack platforms, and (relatively) robust Electronic Intelligence assets to map out an enemy IADS, successful penetration of defended airspace is hazardous.

Stealth, the buzzword in strike aviation for the last 2 decades, is an aid, but not a complete answer. Further, only a small percentage of our strike assets have any stealth characteristics at all. Stealth doesn’t make an attacking airplane invisible to a defender’s radar. Rather, it reduces the effective range at which it can detect the attacker. By flying “between the seams” of defending radar platforms, a stealthy attacker can avoid most enemy defenses. Generally, we’ve seen US forces use this capability to degrade the enemy IADS as a first order of business to allow non-stealth platforms to contribute their weight to the battle.

Rolling back an enemy IADS has long been the first priority of an aerial campaign, almost from the beginning of strategic air warfare.  “Kinetic” methods of rollback, that is, directly attacking air defenses, either through conventional bombs, Wild Weasel tactics and planes, or Anti-Radiation missiles such as the HARM  are all parts of this technique.  “Soft kill” methods such as radar confusing chaff, jamming and other methods to disrupt an enemy communications also reduce IADS effectiveness.

Another way of degrading IADS is to simply overwhelm an enemy with too many targets to effectively counter. This simple saturation method has a couple drawbacks, though. First, it takes a lot of airplanes to do that. Second, it can be pretty rough on those attacking aircrews. So, in  concert with kinetic and soft kill methods, liberal use of decoys can complicate the enemy’s air defense problem. For instance, if each attacking aircraft can deploy two decoys, the enemy suddenly has three times the volumes of targets to service. The negative effect this has on air defenders isn’t merely linear, either. The sudden tripling of possible targets and the confusion that causes can generate “friction” where the responses of the defense to any single target are less effective than would normally be the case.  

Air launched decoys aren’t a new tactic in air warfare. At the height of the Cold War arms race in the late 1950s, as the B-52 fleet began to realize the challenges the Soviet air defense system’s network of radars, interceptors, and guided missiles posed, the Air Force began a program to deploy a decoy to support any World War III missions into the Russian Rodina.  The GAM-72 Quail  (later ADM-20) was a small,  jet powered drone small enough to be carried in the bomb bay of the B-52. With a range of up to 400 or so miles, it could be launched outside the detection range of most air defenses, and still penetrate alongside the real bombers for most of their penetration. While up to 8 Quails could be carried, a more typical load would be two Quails, taking up a quarter of the bomb bay, leaving three quarters of the space available for offensive weapons.

Given that it had to fit inside the bomb bay, the Quail was necessarily quite small.  How do you make a small target look like a gigantic B-52, historically one of the largest radar signatures ever to take to the air? Careful shaping of the wings and fuselage of the drone, as well as placing radar reflectors inside covered by radar transparent fiberglass, gave the Quail almost the same reflectivity as a real B-52. It would be another generation before aircraft designers paid as much attention to using shaping to reduce radar returns as they had on enhancing them.

Quail

While the Quail was quite small by B-52 standards, it was still far to large to be carried by tactical fighter bombers.  In the early 1980s, as Soviet designed air defenses improved and were exported widely to potentially hostile nations, our services began to look at the possibility of decoys for tactical use. In cooperation with the Israelis, who had their own challenges with IADS to be defeated, the ADM-141 Tactical Air Launched Decoy was designed. A simple glider with folding wings, the TALD was small enough that a tactical jet could carry several. Swarms of TALDs were loosed upon the Iraqi air defense network at the opening of the bombing campaign of Desert Storm. TALD was popular because it was lightweight, very simple to operate, and very inexpensive.

But because TALD was a simple glider, it was limited in range. Further, being unpowered, it moved much slower than attacking aircraft typically would. Given a bit of time, a savvy air defender could sort the decoys from the real targets. Refined versions of the ADM-141 included the ability to deploy chaff, and later, by adding a very small jet engine (little more than what a turbine R/C plane uses) giving the TALD both better range, and a speed more comparable to the jets it is simulating.  

TALD

Around the turn of the century, the Air Force, via DARPA, started to look at developing a more capable decoy to replace the TALD.  The program, Miniature Air Launched Decoy, stalled out after a couple years, but the Air Force resurrected it and eventually fielded the MALD as the ADM-160B. There’s the vanilla, turbine powered MALD with a range of about 500 miles, and the performance to imitate tactical jets. Currently, there is a program to upgrade the design with and on-board jamming capability, launch from C-130s (saving pylon space on strike fighters for weapons), and even possibly using the platform as a UAV or arming it as an attack weapon. Given a functional airframe, the possibilities for developing new uses and versions at low cost are limited primarily by the imagination of the acquisition corps.

http://media.defenseindustrydaily.com/images/ORD_ADM-160B-C_MALD_Cutaway_lg.gif

The widespread use of decoys in the early phases of an air campaign, especially supporting stealthy strike aircraft dedicated to dis-integrating an integrated air defense system, will reduce losses and increase effectiveness of our aerial forces significantly.

Comments Off

Filed under history

Daily Dose of ‘Splodey

Bad to the BONE.

Comments Off

Filed under ARMY TRAINING

Is a solution in sight for the F-22 oxygen problem?

The F-22 program has been plagued by reports, and likely one accident, of pilots suffering from hypoxia while flying the world’s most advanced jet fighter. The focus on solving the problem has been on the jet’s On Board Oxygen Generating System (OBOGS), that produces pure oxygen from the bleed air from the jet’s engines.  Many of us were puzzled, as various OBOGS systems have been in use in other platforms for decades.

Now, a new theory has arisen- that the problem isn’t specifically an oxygen supply problem, but rather an aviation physiology issue heretofore not suspected.

Pilots in high performance jet aircraft wear not only an oxygen mask, but also an anti-g garment, known as a g-suit, to help offset the effects of g-forces while maneuvering. By inflating bladders of air in the “speed jeans” around a pilots legs and lower abdomen, less blood drains from the pilot’s brain, delaying the effects of high g, such as greying vision or blackout, or worse, G- Induced Loss of Consciousness, or G-LOC.  G-LOC, where blood quickly rushes from the pilot’s head to his lower body, can leave the pilot incapacitated for some time, as much as a minute. And in a maneuvering fighter jet, it’s highly likely that in that intervening minute, something very, very bad will happen, such as plowing into the ground at supersonic speeds.  G-suits can offset approximately one “G” worth of acceleration. With conditioning and a g-suit, fighter pilots can withstand up to roughly 9 G.*

But today’s superfighters such as the F-22 are capable of more than 9 G turns. Thus the pilot becomes the limiting factor in the performance of the aircraft. So the search was started for a better g-suit, to try to enhance that offset to some level greater than just one G.  A further problem is, the F-22 routinely operates at altitudes far, far above other aircraft. Whereas “teen series” fighters such as the F-15 and F-16 might operate in the 30,000 foot range, the F-22 can cruise at altitudes of up to 60,000 feet.  Humans just cannot survive at that altitude. If a pilot loses cabin pressure at 30,000 feet, as long as he’s provided with oxygen from his mask, he can survive. But at 60,000 feet, that same pilot needs more than just a simple flow of oxygen. Exposed to ambient air pressure at that altitude, the gases diffused in his bloodstream begin to bubble, much like a diver coming up too quickly from the deep. So a pressure suit is needed. But a full pressure suit is a bulky, complex outfit. Think “spacesuit.” They work, but aren’t really practical for everyday use. So the Air Force needed something that was suitable for daily use, and that would be sufficient to give a pilot enough time to recover to a more survivable altitude in the even of a loss of cockpit pressure, either through combat or a mechanical failure.  It also had to serve as an improved g-suit. The solution was an addition to the traditional g-suit. Instead of covering just the legs and lower abdomen, it would also cover the upper body.

The result was known as “Combat Edge.”** Combat Edge is an integrated system of helmet, oxygen mask, pressure regulator, and g-suits for very high performance aircraft. The Navy uses a similar outfit for its fighter aircraft.

Now Flight Global has published an article that says the very system that is supposed to provide protection to the pilots may in fact be the root of the problem:

A compounding factor may be a condition known as acceleration atelectasis. The condition causes the pilot’s lungs to have trouble bringing oxygen to the blood system because pure oxygen–93% oxygen in the Raptor’s case– and high gravity loads set up the pilots for a condition where the air sacs in the lungs suffer partial collapse.

The result of acceleration atelectasis is the so called “Raptor cough”-where F-22 pilots have a pronounced cough as the pilot’s body attempts to re-inflate the sacs under normal atmospheric pressure on the ground.

Earlier tests would not have caught the problem because the breather device used to test the Combat Edge system does not compensate for pilot’s lungs being unable to expand as readily. The breather device always draws the same volume of air.

A lack of ability to test for restricted expansion kept the condition from being seen as a problem. The restricted breathing could lead to hyperventilation symptoms or even bigger issues if the pilot is suffering from acceleration atelectasis.

However, the source says, the pressure-garment problem has been a known concern since at least 2000 when a similar garment provided by Boeing was being flown. But at that time, the USAF did not believe that the extra pressure was a serious concern. Now however, the USAF is starting to believe that the Combat Edge is behind the Raptor’s woes. But while current USAF research is pointing to the Combat Edge as the primary culprit behind the F-22′s maladies, the source says that it is probably only part of the problem.

During early development and use of the F-22, it was very rare for a pilot to fly more than one mission a day. But as it has entered widespread service, more and more pilots are pulling a “double turn” and the cumulative effects of acceleration atelectasis may be showing up and causing some of these issues.

The intricacies of aviation physiology are beyond me (I’m not a doctor and I don’t play one on TV). But if this is the cause of pilot hypoxia complaints, it is somewhat troubling, as I can’t see a short term fix that allows the jets to maintain their full performance envelope. And the whole point of buying them was that enhanced performance envelope.

Thanks to Roamy for the tip on the article.

 

*Above about 6 G, breathing ceases to be an autonomic function, and so the oxygen system must “pressure breathe” for you, forcing air through the mask and into you, and forcing you to consciously exhale, which just also happens to be a part of the “M1 anti-G” muscle maneuver.

**Virtually every program in the Air Force has a code name. “Combat” is one of several family of programs. Another example is the “PAVE” family of programs.

2 Comments

Filed under Air Force

Beyond GPS for JDAM

The Joint Direct Attack Munition, the GPS/Inertial guidance kit that transforms a dumb bomb into a smart bomb has been a smashing success. And it is only one of many GPS guided weapons in the inventory today. The problem is, GPS guidance relies on an external source of information, that is, the constellation of GPS satellites.  GPS is jam-resistant, but not jam proof. Since the early days of the GPS program, the fear has been that sooner or later, someone would be able to consistently jam the signal. 

Not surprisingly, DARPA, the Defense Advanced Research Projects Agency, would like to develop an alternative to the reliance on GPS that current technology provides

I’m not exactly bright enough to delve into the technical aspects of “Chip-Scale Combinatorial Atomic Navigator (C-SCAN)” but I do understand the basics of inertial navigation. Originally using gyroscopes and precession to measure the movement of a platform, most Inertial Navigation Systems today use ring-laser gyros today that use doppler shift in the laser light to measure displacement. And if you know how much a platform is displaced from its starting point, that is, the sum of all accelerations (and decelerations, which are just accelerations in a different direction), you can compute the current location (and velocity) of the platform. 

But INS systems tend to have significant drift errors accumulating over time. Today, most INS systems update from time to time with GPS. That means that even if the GPS is unavailable, the INS platform provides at least some level of navigation capability.  For instance, the JDAM is always labeled as GPS guided, but in actuality, it has an INS guidance system with GPS updates.

If DARPA can work with industry to build a small, reliable system that is completely free of external input, the potential vulnerability of our current generation of GPS assisted weapons would be erased. Other applications on the battlefield, such as Blue Force Tracker systems would also be enhanced.

8 Comments

Filed under Around the web

410 Cougars

The Canadian Forces were, IIRC, the first foreign force to operate the F/A-18 Hornet (though they designate it the CF-18). They operate a fairly small, but highly respected force. Learning to fly takes time. Learning to fight a Hornet takes 9 months, and a lot of hard work, as well as some natural aptitude.

410 Squadron (Cougars) is the equivalent to what our Navy would call the Fleet Replacement Squadron. That is, it provides transition training into the Hornet, and refresher training for folks that have been away for a while.

A few years ago, an American network debuted a show called American Fighter Pilot, about students transitioning from the T-38 into the F-15C Eagle. It only aired one or two episodes before it was yanked for low ratings. But Canada, having subsidized television production, doesn’t really have to worry so much about ratings. So I came  across an 8 episode series called “Jetstream” that follows the fortunes of a class of students spending 9 months at the Fighter Pilot Training Course. Lot’s of good photography.

There’s Episode 1. If you watch it at youtube, you should be able to easily follow up with the rest of the episodes.

4 Comments

Filed under planes