The XC-142 Tilt-Wing V/STOL program had its roots from the recommendations from a government advisory group in 1959. The group recommended that a full-size aircraft was required, with specific requirements for the Navy and Army. Beyond the obvious military applications of such a system, there were also many that felt that the plane could also have considerable civilian applications.
The group noted that all previous VTOL programs at the time had been built to illustrate a particular principle, and the fact that it could be accomplished. Few of these concepts had any operational military capabilities. Consequently, with the XC-142, it was decided that this system would be tested in an operational environment.
With that goal in mind, it was decided that the system would fulfill requirements for all three military services. Thus was born the first tri-service VTOL.
In 1961, a Request for Proposal was released, and in September, the proposal from Vought-Hiller-Ryan was announced as the winner. It was also announced that the Air Force would manage the program with the cost of the program to be shared equally by each of the services.
Vought Aeronautics Division of Ling-Temco-Vought was the prime contractor, with Hiller and Ryan serving as the major subcontractors. Vought subcontracted the design and fabrication of the empennage, aft section, engine nacelles, and wing to Ryan. The overall transmission system and selected components were subcontracted to Hiller, which was also responsible for the flap and aileron fabrication.
Compared to previous test bed experiences, the new V/STOL was a large aircraft with significantly optimistic performance goals, similar to those of the Army's DHC-4 "Caribou" transport.
The XC-142 grossed out at about 16900kg loaded with an empty weight of about 10780kg. The plane had a fuselage length just exceeding 17.7m, with a maximum height of 7.9m and a sizable wing span of 20.6m. The model carried a single tall vertical tail that provided 12m2 of area. The wings carried large trailing double-slotted flaps the entire length of each wing and were mounted high on the fuselage.
The bulky fuselage was designed to carry significant cargo, with the cargo compartment being 9.15m in length with a 2.1m height and width. That volume equated to about 32 full-loaded troops and gear, or four tons of cargo. In addition to that capability, there was also the ability to carry 370 litres of fuel. There was also a planned capability for auxiliary tanks which would greatly add to the range.
Power consisted of four 3080hp General Electric T64-GE-1 engines, mounted in nacelles on the wings, which were all cross-linked together. Each drove a giant four-bladed 4.7m Hamilton-Standard fiberglass propeller, the tips of each practically overlapping each other.
Later in the program, Hamilton Standard would provide an improved version of the propeller using the 2FF blade design, which featured a wider planform, rounded tips, and a more pronounced twist than the earlier 2EF blades. The goal of the new design was to improve aerodynamic load distribution and overcoming a static load problem.
The four engines also drove a fifth propeller, a three-bladed fiberglass type, in the tail through an interconnected gear and shaft train. Therefore, power was available to turn all five propellers when one, two, or three engines were shut down. The tail propeller rotated in a horizontal plane and was declutched and braked for cruise flight.
Tying all this power together was obviously an intricate and complicated setup. Through cross-shafting gearboxes, the rotation from each engine was brought together at the top of the fuselage. The power was then sent back to the tail rotor through a tail propeller shaft, into the tail propeller gearbox, and on to the variable pitch tail propeller.
The propulsion system of the XC-142 was definitely an over-powered situation. For example, the plane could lose an engine on take-off and still clear a 15.25m barrier in 122m carrying a 4500kg payload. Also, with all engines operating, the plane had a rate of climb at sea level of 34.5m/s. On a hot day, even with an engine out, the XC-142 showed a climb rate of 17.8m/s.
Control of the craft during the ascent stage was intricate to say the least with roll controlled by differential propeller pitch. Pitch control was accomplished by the eight-foot, three-bladed variable pitch tail rotor. Yaw control was provided by ailerons powered by propeller slipstream deflection, actually a second VTOL concept being employed in the XC-142.
The craft had a unique capability with the main lift system in that the wing was capable of rotating through 98 degrees instead of the expected straight-vertical position. The wing tilt mechanism consisted of two screw-jack actuators driven by a centrally-located hydraulic motor. The tilt was controlled by a variable rate switch on each collective lever, or by a constant rate switch. This allowed the plane to hover in a stationary mode in a tailwind condition.
The trailing edge of the wings carried three-section, double-slotted flaps in three sections, with the center and outboard sections operated also as ailerons. The flaps were programmed automatically with changing wing tilt, although the pilot had an override capability. Leading edge slats were used for stall suppression, and were mounted outboard of each engine nacelle and operated automatically as a function of flap position. The vertical tail was operated as a standard rudder-and-fin set-up, which supported the slab-type unit horizontal tail assembly.
The magic in the design was probably in the intricate control system, a fully-powered irreversible type with artificial feel forces and powered by dual independent hydraulic systems. Dual cockpit controls, consisting of conventional rudder pedals, control sticks, and collective levers for all take-offs and landings, provided the highest technology of the system.
The XC-142 design also considered logistics implications, in addition to the VTOL design goals, with the tail rotor rigged to fold to the port side to reduce the storage length and protect against damage during a loading operation.
The first XC-142 was rolled out in early 1964 with its first conventional flight being made in September 1964, its first hover three months later, and first transition two months later than that. The Air Force extensively tested the XC-142's capabilities with cargo flights, cargo, and paratrooper drops, along with desert, mountain, rescue, and carrier operations.
In 1966, one of the XC-142s passed operational tests to prove the model in carrier operations. In quick succession, the plane accomplished 44 short take-offs and landings, along with six vertical take-offs and landings from the USS Bennington.
The carrier trails were accomplished using the number five prototype, which was crewed by both USMC, Navy, and Army pilots. The flight regime covered VTOL operations at a variety of speeds, which occurred at wind conditions from 10 to 55km/h. A large variety of wings and flap tilt angles were used during the testing. Also, there were landings accomplished with three and six degree glide slopes. In an amazing demonstration, the plane negotiated a 360-degree turn within the width of the flight deck. That same year, one of the prototypes was also tested in an overwater pickup operation. The plane lifted a man from a life raft to determine its capability for rescue and recovery. A standard Navy horse collar sling was attached to 38m of cable and then lowered through a floor hatch just aft of the cockpit. The tests proved that there were no problems with effects of the propeller downwash or slipstream turbulence.
The program called for the building of five prototypes, but cross-shaft problems, along with some operator errors, resulted in a number of hard landings causing damage to the complete fleet.
The most serious of the mishaps, resulting from a tail rotor driveshaft failure, caused three fatalities. The May 1967 accident took place near the Dallas, Texas, LTV plant and occurred in a heavily-wooded area where fire started after the impact.
The flight plan for the ill-fated prototype included a rapid decrease in altitude from 2440m to 915m, effectively simulating a pilot rescue under combat conditions. A nose-over at low altitude followed, from which the crew could not recover. The crash aircraft was XC-142 #1 which had flown 148 times at the time of the crash.
Other incidents included the following:
Aircraft #2 - On October 19, 1965, this craft experienced a ground loop causing extensive damage to the wing and propeller.
Aircraft #3 - On January 4, 1966, this model made a hard landing in the vertical mode. There was significant damage to the fuselage. The wing of this plane was late mated to the Number #2 for further testing.
Aircraft #4 - On January 27, 1966, an engine turbine failure caused the overriding clutch to engage, causing extensive damage to the wing, outboard aileron, the number two nacelle, aft engine shroud, and fuselage. It was later used by NASA for further research.
Aircraft #5 - ln December of 1966, a ground accident caused major damage to the fuselage, nose, wing, and propellers. The incident was caused by pilot error who failed to activate the hydraulic system, which resulted in no brakes or nose wheel steering.
The final decision on the disposition of the aircraft occurred during the Category II Operational Suitability Program, which was conducted at the Air Force Flight Test Center. The testing consisted of 113 flights, totaling 163.9 hours, which was accomplished between July 1965 and August 1967.
Three of the XC-142s also participated in a major operational test demonstration during the program, where the planes participated in demonstrations of VTOL, STOL, and movement of Jeep-mounted 106mm recoilless rifles, unloading of three-quarter ton trucks with towed 105mm Howitzers, dump trucks, and 450-kg A-22 containers.
For a typical XC-142 design mission, the plane could operate with a gross weight of 16900kg, including a four-ton payload. At that weight condition, the plane could take off vertically, cruise 370km near 480km/h, hover for ten minutes, and then land.
One of the limitations found in the plane, even though the overall test results were very positive, was an instability between wing angles of 35 and 80 degrees which was encountered at extremely low altitudes. There were also high side forces which resulted from yaw and weak propeller blade pitch angle controls.
Another XC-142 complaint was the excessive vibration and noise in the cockpit, when coupled with an excessively high pilot workload, and which presented a considerable challenge in the cockpit. The program was a considerable effort, with 39 different pilots flying the prototypes for a total of 420 hours.
The greatest national exposure the XC-142 received during its flight test program occurred when the #4 prototype participated in the 1967 Paris Air Show.
The technology contributions which were derived from the program were felt to have made the program worth its effort. In retrospect, it has to be assumed that if the mechanical problems experienced with the XC-142 could have been solved, the plane could well have achieved operational status.
The only remaining XC-142, #2, currently is on display at the Air Force Museum at Wright-Patterson Air Force Base near Dayton, Ohio.
S.Markman & B.Holder "Straight Up: A History of Vertical Flight", 2000
Technical data for XC-142A
engine: 4 x General Electric T-64 turboshaft, rated at 2095kW,
wing area: 49.7m2,
empty weight: 10250kg,
max speed: 667km/h,
range with max fuel: 756km,
range with max payload: 370km
|Pete Bitar, e-mail, 27.04.2015|
What a great aircraft. I wonder, if one was able to get the original drawings and update everything with modern control systems, computerized systems management (to lighten the workload in the cockpit), and modern materials to lighten overall aircraft weight, with more efficient engines, could it fly again and be a real competitor? I believe so, but it would take a big commitment of funds and time. It'd be a great tribute to, from all I've read, a great team of people that sacrificed so much to make it fly in the first place. Modern tech could solve the problems that killed it then.
|Bart van der kallen, e-mail, 25.10.2014|
Great story's to read.
Sorry for my bad englisch.
Ist there anybody who have THE drawning of THE plane.
I'm startet to build a rc scale plane .
THE software is already there. A prototyp is already flying ((semi-scale)YouTube)
i want to build a wooden model in a scale of 1:7
Thank u very mutch .
|Catherine Hardesty Lugo, e-mail, 14.11.2013|
My dad, Ed Hardesty, was a test pilot at LTV during this time
|Joseph Engle, e-mail, 05.01.2013|
I remember the day the 142 went down. My mom picked me up from Paul Keys elementary school in Irving, and told me my dad, Joe Engle, was OK, but there had been a crash. Being the son of a test pilot, I'd gone to a number of funerals for pilots, but never a memorial for three in one day.
The crash deeply affected my dad, especially the loss of Stu Madison. Along with Bob Rostine, if you saw one of them, you saw the other two.
|eflatguy, e-mail, 20.12.2012|
Stu Madison was one cool dude.
I was in scouts with his son.
I remember him being a real trickster, while giving a lesson in navigation and compass usage.
After a while, he revealed the magnet he had palmed in his hand.
That was fun.
|james, e-mail, 09.08.2011|
Where are the other four a/c now? The ones that crashed.
|polo, e-mail, 15.06.2011|
One of the other crewmember's last names was Jester. I was friend's with his daughter.
|Bob Madison, e-mail, 07.06.2011|
My son, Stu's nephew, alerted me to this site; it's snswered a number of questions that have lingered in my mind. Another LTV pilot had told me (at my brother's younger daughter's wedding) that it was a "pin" failure that caused the tail rotor to go to full pitch. So LTC Chubboy's more detailed explanation is especially appreciated.
|Doug Sheldon, e-mail, 28.04.2011|
I was stationed at Edwards, AFB (F-111 program) during the same time frame, mid to late 60's, as the XC-142 test program. The Army's equivalent to a USAF flight control specialist was a drone MOS. An Army Spec 5 was assigned to base A&E squadron for the XC-142 and I joined him a few times on work assignments when there wasn't much F-111 activity. The XC-142 was a hydraulic nightmare. But, what a challenge, as were many of the one of a kind aircraft at Edwards.
|Mark Peterman, e-mail, 23.04.2011|
Shaun Jester, his mother Sue and sister are all still missing Charles. Shaun and I are friends from grade school/boy scouts. My father (also LTV at the time) and I have always loved Shaun and Sue. We were 45 years old when Shaun finally told me about how they were notified that tragic day. It was an emotional moment and apparently one that he had not confided outside the family (not even his wife) until that day. Shaun now works for another defense contractor in Ft. Worth and Sue is glad he is not a test pilot! I was way too young (b 1963) to have met Charles and only know of him through his family and some photos. Since Shaun and I still see each other (he is my brother in Christ and Scouts!) if anyone has any information about Charles they would like to send their way, drop me a line please. I will see him again next week.
|Ed Flinn, e-mail, 28.07.2010|
I was an aero engineer ~ propeller performance specialist ~ on this project from 1962 until the program was canx. John and Mary Ann Omvig and their two children were our next door neighbors and Lake Arlington water skiing buddies with our young families. Such a terrible loss, all three extraordinary aviators. John was a survior of jet fighter crash on a carrier in the Korean war.
The failure that caused the crash was the fracture of a funk strut on the tail prop control rod. As the ship began to pitch over, the pic (apparently)decided he had a horizontal tail aoa problem (all moving horizontal stabilizer/elevator)thus elected to go deeper into conversion to vertical flight ~ the tail prop had gone hard-over in the nose down direction with catastrophic results. There was some speculation that had he elected to accelerate to wings down conventional flight the he might have recovered...but not likely. After the crash we had one of the ships in the structural test lab at LTV, with vibration generators on just about every control system. It soon became obvioius that the funk strut assembly was readily excited in its natural frequency by many normal modes of the ship...clear failure modes. In hind sight, and by today's standards, the program should have had far more structrual dynamics testing before flight.
|Tom Humphrey, e-mail, 19.07.2010|
I was a LTV flight test engineer working the A-7 program but knew most of the LTV test crew that worked the XC-142A. Emailers T Morrow and Robert Chubboy were correct on the names of all three crew members killed on the fatal demonstration flight. John Omvig was the co-pilot and Charlie Jester was operating the winch in the aft section. Jester did not have an ejection seat. As I recall Stu Madison ejected as the aircraft pitched over passed -90 degrees. John Omvig ejected from the inverted aircraft just before impact with the ground. All the LTV test pilots were top notch professionals. Stu Madison though was one cool customer and it was well known that he was John Konrad's (Director of Flt Ops)golden boy and was headed for greater things. It was a terrible trajedy
|Jesse P. Jacobs, Jr., e-mail, 28.05.2010|
Ross Beedle wanted to know which XC-142A was on the USS Saratoga in May 1967 flying off the carrier going to Rota Spain. I was the Test Director & I know it was Airplane #4 the last three numbers on the tail were 924 It is currently at the Air Force Museum, Wright-Patterson AFB, Ohio. I am Colonel Jesse P. Jacobs, Jr. USAF (Ret).
|T Morrow, e-mail, 08.01.2010|
The pilots on the fatal flight were Stu Madison,
Charlie Jester, & John Omvig
|rudager, e-mail, 28.12.2009|
I'll tell you who was in the tail of that contraption..
SOMEONE WITH GIANT F*CKING BALLS
I mean damn, what were they thinking!?
|Jim Wilson, e-mail, 07.11.2009|
I was 18 and driving on the East side of the lake when the aircraft went down. Myself and Martin Herndon waded through the Willows and Marsh and I was one of the first to arrive until now I didn't know the Captains name but always wondered who was in the tail section of the aircraft.
|Richard Elston, e-mail, 15.07.2008|
I remember the crash in May 1967. One of the other crewmember's last names was Jester. I was friend's with his daughter.
|Ross Beedle, e-mail, 23.05.2008|
I took photos from the port side catwalk of the USS Saratoga (CVA-60)of one of the XC-142A planes on 10/May/1967. The Saratoga deployed from Mayport, Florida, in early May to the Med, and carried one of them to the Mediterranean, where it departed the ship for Rota, Spain, then on to the Paris Airshow. It was rather amazing to see this machine move only several feet forward and then lifting off the deck rather rapidly. It would be interesting to know which one of the remaining four aircraft this one was. I see know way from the photos that I have that would identify it. Should any one care to see the pictures that I have, they can be found on my flikr page at http://flickr.com/photos/9789926@N07/
|Willy Webb, e-mail, 07.05.2008|
I was part of the crew that horrible day and would love to get in touch with the grandson of that wonderful pilot, Stu Madison.
|arthur b north, e-mail, 22.02.2008|
SFC Arthur North was Line Chief on the XC 142 from 1964 until I retired on May i 1968. and I would like to her from any of the old crew who were there during that time. I am in touch with William Dunlap who lives in Gilmer, TX and I hope to hear from then Col Billy Odneal, or Lt Col Robert Chubboy. Chuck Teague was my assistant during those years. email@example.com 813 238 8976 (Tampa, Fla)
|Kevin Teague, e-mail, 18.01.2008|
Hi, I was curious if any of you gentlemen remember my father,Chuck Teague, He was a Chief Warrant Officer, Army Aviator, and worked on the XC142 project in some capacity. We were at Edwards for 3 years from 1964 thru 1967, and were then transferred to Langley. Dad passed away in 1994 and I never really got to talk to him about the pictures I got after he passed on.
|SFC Arthur North ret, e-mail, 15.11.2007|
I was on this project with Lt Col Chubboy and would like to hear from any of the other Army or Air force personnel who were members of this Tri Service Test team (firstname.lastname@example.org) yes I am STILL alive at 81years old riding a motorcycle and flying a light Sport aircraft in Tampa ,Fla
|Robert A. Chubboy, LTC USAR Ret., e-mail, 31.10.2007|
I was the Army prime XTP on the XC-142 and accumulated about 130 flight testt hours including the first non-stop flight from EAFB to Dallas w/Colonel Jesse P. Jacobs. I can attest to the tragic loss of Stu Madison, John Omvig and Charlie Jester in the May 17 (I stored April 17) and have maintained ever since that had Stu Madison, the professional that he was, been doing an engineering flight test where he was tuned to every little quirk particularly in the flight controls he would be alive today. But, no he was doing an operational test, a very demanding one requiring a multitude of aircraft conviguration changes starting with engagement of the tail rotor raising the wing while in a descending spiral path from the above reported 2500m to the target of 900m and encountering, not a tail rotor drive shaft failure but a loss of tail rotor pitch control. This failure I recall to have been caused by a bell crank that convertes horizontal control rod motion to vertical control motion and hence the variation of the tail rotor pitch in response to the pilots requirement for nose up or nose down commands. The failure resulted in the tail rotor going to the full nose down command some 11 seconds before continued raising of the wing slowed the aicraft to the point where the horizontal tail was no longer able to overpower the tail rotor and the aircraft pitched nose down. Before ejecting Stu did manage to reduce the wing angle somewhat but it was too late. I repeat it was a control failure not a drive shaft failure and it was the result of vibration induced failure of the bell crank mentioed above. It was this same day when our test force director, Colonel Jacobs was making his second plea before the WPAFB Program Director to suspend further tests of the machine until a vibration survey was conducted by LTV.
The chief test Pilot, AF LTC Gay Jones and I had been noticing an unidentifiable vibration as far back as January. Based on our comments to Colonel Jacobs, he suspended military flights in March. The failure as I recall was the above described bell crank and upon inspection the four remaining aircraft were found to have thesame bell crank with vibration induced cracks. When the vibration survey was finally conducted, the bell crank designed for a 42g vibrator load was actually seeing 172g. As I am participating with Rob Ransone to clear the air on several issues. including the above failure, that cropped up during our test force's 45th anniversary reunion last week. I would be very appreciative of any reader's comments. Though my bark peels easy, it's tough and I can still take criticism - be nice though! Chub
|Rob Ransone, e-mail, 10.10.2007|
I was the USAF's Chief Flight Test Engineer for the Tri-Service Tests at Edwards, primarily for the Category II performance and stability and control flight tests. Our biggest concern for the performance tests was how to test the vertical takeoff/hover and STOL configurations and how to translate the test data to sea level standard temperature. I conducted the first hover tests at California's Point Mugu NAS because at that time of year, at dawn, the test conditions were sea level and 59 degrees Fahrenheit. Our in-ground effect heavy weight hover tests enabled me to predict the in-ground effect hover performance at Bishop (5000 feet altitude) to within inches! Basically, I used helicopter performance data analysis for hover (Cp/Ct -- power coefficient/thrust coeffient, at density altitude). I ignored the tail rotor because its thrust varied up and down with pilot longitudinal control stick movements, its Cp/Ct was assumed not too different from the main props, and its total thrust was small compared to the main props. For STOL (short takeoff) I used a specific energy analysis of E/(Cp/Ct) versus takeoff distance, which put all of the various STOL wing angle takeoff data on one line. I also prepared a hover performance circular sliderule in which the pilots could enter the cockpit torque-meter reading of the four engines, the pressure altitude and the ambient temperature to determine their safe vertical takeoff and landing weights. The USAF subsequently patented this for me, which resulted in US Patent Number 3528605 from the United States Patent Office in September 15, 1970. A great bunch of professional pilots, engineers, instrumentation and maintenance people, and LTV contractor support. What fun!
|Phillip Massie, e-mail, 05.08.2007|
Hello, I'm almost certain that one of these planes landed on my ship the U.S.S. Ogden LPD-5 in the 1960's [ 1967 - 1969 ] while we were underway, possibily off the coast of San Diego or Long Beach, Ca. We had a comparatively small, especially narrow helo-deck compared to Carrier's or LPH's. I remember being somewhat alarmed by the speed and size of the aircraft as it set down and "skidded" forward with it's nose ending up not too far from the mess hall bulkhead where I was standing. I thought the pilot was very skillful in pulling it off, although in retrospect it now seems that it was rather risky. I think I may still have a photo of it. Does anyone recall the exercise?
|SFC Paul D. Fulk, Army Retired, e-mail, 27.07.2007|
I have always remembered the XC-142. I was at Edwards AFB and work ont the XC-142 for almost the 2 1/2 years. I was one of the crew memebers that flew on one of the aircraft for the Demo that we did. one day if I could find a model of it. I would like to have one. I still think it is a great design for a air craft that could be used today.
|Stu Madison, e-mail, 21.07.2007|
Stu Madison was my grandfather. Never met the man, but I appreciate the kind words on his behalf.
|LYNN GARRISON, e-mail, 23.06.2007|
None of the articles on the XC-142A mention the crew lost in the fatal accident. LTV's Chief Test Pilots, Stu Madison, was captain on the flight. He was looked to by LTV President Thayer as a future president of the corporation. I cannot remember the other two, but I do remember Stu from the time I visited LTV, Grande Prairie, with my F4U-7 133693 during 1967. He flew it to make sure it was safe for Thayer to take a quick flight.
Do you have any comments concerning this aircraft ?