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Old Viper Tester

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About Old Viper Tester

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    Dayton OH USA
  • Interests
    Military flight test, R&D, and prototype aircraft.

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  1. Red Flag 85-2: VF-31

    VF-31 at Nellis AFB for Red Flag Exercise in March 1985. BuNo 161866 BuNo 161858 BuNo 161860 BuNo 161862 BuNo 161864 BuNo 161866 BuNo 161868 BuNo 161135 Thanks for looking, Sven
  2. VF-124 CarQuals - 1982

    Red Dot - I'm sure it was deliberate. Seeing as the entire air wing was ashore at the time and Ranger was preparing to take on an air wing rotation, all of the air crew quarters were vacant. I was surprised that the berths they put us in were marked for one of the air wing fighter squadrons. Would've thought the fighter pukes would have rated better, but then maybe the rest of the ship took a vote and wanted to counter the fighter pilot ego? Sven
  3. Red Flag 84-2: VF-142

    I thought it was one of the "new" Tactical Paint Scheme grays at the time. I've not compared t to any point references though. Sven
  4. These T-28Bs were on the transient ramp at Nellis AFB in March 1981... BuNo 140046 BuNo 137641 BuNo 138122 BuNo 138247, note the Rear Admiral's one-star flag beneath the cockpit They certainly made a different kind of roar in the overhead pattern when you were used to A-10s, F-4s, F-15s, and F-16s! Thanks for looking, Sven
  5. Red Flag 84-2: VF-142

    VF-143 was paired with VF-142 for this Red Flag exercise. BuNo 161418 BuNo 161421 A bit fuzzy here! BuNo 141422 BuNo 161435 BuNo 161417 In other news: The motherboard in my iMac died this weekend, so I'm plodding along on an old laptop while I figure out where I want to go from here. The Macs are relatively expensive, but I like the user interfaces a bit more than the PCs. Then there is the buy now or wait till after the hols to see if there are any better deals consideration. The bottom line is that slide processing will definitely slow down in the interim. I may have to finish re-setting up my modelling workbench in the aftermath of my man cave flood this past summer! Idle hands and all that. Thanks for looking, Sven
  6. VF-143 at Red Flag 84-2

    Should have those scanned and cleaned this weekend. Sven
  7. YA-7F

    The bare exhaust nozzle arrangement resulted in negative pressure on the 'turkey feathers' and would result in the same conditions as on the early F-15s, where the fairing pieces would break off. Hence the removal of the panels on the F-15. LTV chose to shroud the nozzle just as they had with the original A-7. Unfortunately, in order to provide enough clearance for the F100 nozzle, the shroud is not as elegant/aerodynamic as the original TF41 shroud. I expect it created a significant amount of drag. I also expect LTV required use of the afterburner to meet their proposal specs. Certainly if they wanted any supersonic capability, if only for a dash, use of the AB would have been necessary. The YA-7F did achieve supersonic conditions, but I don't know the conditions. Interesting that LTV originally looked into putting an afterburner on the A-7D TF41 turbofan. If nothing else, a new unique engine would have been a tough logistics sale over using an F100. Sven
  8. VF-143 at Red Flag 84-2

    At the risk of adding fodder to Tony Oliver's epic saga of 1/72nd F-14s over in WIP, here are some images of VF-143 "Pukin' Dogs" at Nellis AFB for a Red Flag Exercise in 1984. BuNo 161425 BuNo161426 BuNo 161432 BuNo 161419 BuNo 161281 Thanks for looking, Sven
  9. VF-124 CarQuals - 1982

    In 1982, my USAF Test Pilot School class visited CV-61 USS Ranger as she was steaming down the California coast. The objective of the visit was to see how the 'other guys' do it. We were shuttled out to the boat in C-1 CODs, spent the night in forward quarters under the catapults - whoosh, bang, wirr continuing through much of the night for A-6Es doing their thing. In the morning, a briefing on carrier ops and then left to our own devices to watch VF-124 Tomcats do their Carrier Qualification exercise. After lunch, off to NAS North Island via CH-46 then a long drive back to Edwards. The deck was relatively empty, but watching the activity for recovering each jet and then marshaling it up to the cats for another go certainly gave one a certain respect for the choreography required to get this done without a misstep or mishap. Made me appreciate the opening scenes of "Top Gun" all the more - I thought the carrier deck sequences were one of the better aspects of the movie. And the Tomcats, great aircraft. My apologies for the lighting. I had asked if we couldn't steam northward to get better light from the Pri-Fly, but the crew would have none of it. Go figure. For those who track such things, MODEX and BuNo: 161771 NJ401 160692 NJ436 160693 NJ437 160911 NJ662 161144 NJ670 161165 NJ674 In 1987, I revisited USS Ranger. As part of my assignment at the Ministry of Defense. I was to be the carrier suitability expert, even though I was a USAF exchange officer. The thinking went something like this from my commanding Group Captain: We (the UK) don't operate carriers anymore, you (the US) operate carriers, so you are going to be our carrier suitability Subject Matter Expert. I went to point to my USAF badges, but our uniform-of-the-day was civilian business suit, so the gesture was kind of pointless. I arranged to get a carrier suitability indoctrination from some US Navy offices in Silver Spring Maryland and then off to Point Mugu to get some carrier ops orientation from VX-4 (operational test squadron). Got a couple of flights each in their F-14s and F-4s going out and back from Pt Mugu to Ranger. The reason for the west coast visit was that there was no carrier doing air ops off the east coast at the time. Unfortunately, my camera was in the shop, though I don't think the USN guys would have let me carry a camera anyway. Thanks for looking, Sven
  10. YA-7F

    I see that TheRealMrEd is working on a "Super SLUF" over in the WIP section: Maybe the pics below will provide some additional information/inspiration. The YA-7F was an attempt to create a faster close air support platform to supplement or replace the A-10. The old TF41 turbofan was replaced with a P&W F100 engine, the fuselage lengthened, the vertical tail enlarged, a leading edge root extension (LERX) added, and the horizontal tails "flipped" to create anhedral vs the original A-7's dihedral. In the end, the proposal was rejected in favor of using F-16s for fast response and soldiering on with the A-10 for heavy lifting and loitering. Here is USAF s/n 71-0344 showing the un-shrouded F100 exhaust. Note the orange wiring and strain gauges along the nozzle fairings at the 12,3,6,and 9 positions. The orange wiring and components in the avionics bays are also test instrumentation. Nose on showing the horizontal tail anhedral. '039 and '344 with shrouded exhaust. USAF s/n 70-1039 used for high-AOA testing with spin recovery chute assembly surrounding the engine exhaust. Spin chute load distribution straps running the length of the aft fuselage. Spin chute attachment assembly at the top of the exhaust shroud. The cable connecting the the chute running around the left side and into the compartment below the shroud housing the spin chute itself. Thanks for looking, Sven
  11. Piper Enforcer

    Maverick - I'm fine with the the 'right click and save' for personal use, otherwise there wouldn't have been much point in posting them here. Besides, you never know when the next data storage debacle will occur (a la Photobucket) and then where would we all be? Good luck on your P-51 conversion. As for the XL, I'm holding a little hope that Skunkworks will scale down their 1/48 kit. Until then, I'll keep planning on bashing the old Monogram kit. I'll eventually post some XL pics beyond what I posted for reference in Pappy's WIP (how's that going BTW?). Right now I'm scanning Tomcats and Eagles from Red Flag exercises from Kodachromes in my spare time - a relatively slow process... Sven OVT
  12. NT-33A Variable Stability Simulator

    Considering the F-94 design actually started with a T-33 fuselage, just swapping the nose just before the windscreen is what I was counting on as well. The farthest I got was making a resin duplicate of the Heller F-94B nose with the intention of putting it on a Hasegawa T-33, but that was the state of play about ten years ago and it is still in the box. I don't remember the cause of the YF-22 problem. In general the PIO gets started because of delays in the flight control response, due to mechanical design (dead band, friction and breakout, etc) and, possibly, pilot reaction time, the pilot control inputs end up being 180 out from what the aircraft is doing. Continued inputs generally make the amplitude of the oscillation worse. An F-4A actually disintegrated attempting a low-level speed record at Holloman AFB (Sageburner?) due to PIO exceeding the structural load limit of the airframe. There is an amazing film tracking the (practice?) flight showing the aircraft breakup, the fuel ignites in a fireball and the two J79 engines proceed through the fireball. Altitude permitting, and assuming the aircraft is well damped, the best course of action is to stop making inputs and hold the controls at neutral until the aircraft settles down. Then try to maneuver again. Fly-by-wire can often be worse, because in addition to any mechanical delays, the flight control laws may add delays as well, depending on the number of operations/calculations required to enact a control movement and similar considerations for the feedback loop. We're talking milliseconds here, but it can be a real concern. Beyond that, we get into a bunch of feedback and control theory in which I probably remember enough just to be dangerous. For the stick "feel" in fly-by-wire, in most center stick aircraft, the stick does move and the system has resistance mechanisms to give the cockpit controls feel, just as springs and bob-weights provide feel for some mechanical flight control systems. The "feel" often being a function of angular rate of motion and/or Gs. The sidestick controller in the F-16 originally did not move at all, and even though the pilots would feel in their bodies or visually recognize the aircraft motion/response to their control inputs, they would not get the tactile sense in their hand of the stick moving and thus over control the aircraft. The answer was to let the stick move, but only about a quarter inch deflection measured at the top of the stick. That little bit of motion is enough to give the tactile feedback that applying pressure to the stick is actually moving something (which is moving the aircraft) and most pilots readily adapt to it. Sven
  13. NT-33A Variable Stability Simulator

    Thanks Giorgio. I can truly say that I consider myself very lucky in my USAF career. All of my assignments can be boiled down to three categories: flight test engineer, technical intelligence analyst, or systems acquisition programs flight test manager. All were very interesting and rewarding. I sometimes wish that I could have gone to pilot training or got to do some rigorous engineering design in line with my aero engineering degree. Most of the engineering I did in the USAF was evaluating what others (contractors) had proposed or produced. But then, the USAF paid for my engineering degree, so it was fair that they determined how I used it! Sven
  14. Tigers in the Sky

    Just a few images of Northrop flight test operations at Edwards AFB in the 1980s... F-5E, USAF s/n 71-1418, seen in 1983 with YAPS test nose boom fitted: Test missions without the nose boom in 1984: RF-5E, s/n 71-1420 I know its fuzzy, but it shows the placement of the camera aperture covers. Tiger motif on the vertical tail... Was it Airfix that did an RF-5E in 1/72? RF-5E, s/n 80-0334, in Malaysian markings. Ready to take Runway 22... RF-5E, s/n 84-0199, with refueling probe and Saudi markings: F-5E, s/n 72-0891. Okay, this one as shown is no longer a Northrop test bird, but it retains the double tiger tail markings and F-5 operators flag panel beneath the windscreen from its test days with Northrop. Here, it is with the 425th Tactical Fighter Training Squadron, 405th Tactical Training Wing stationed at Williams AFB Arizona. Thanks for looking, Sven
  15. The NT-33A, USAF s/n 51-4120, was a variable stability in-flight simulator. It was owned by the Air Force Flight Dynamics Laboratory and, later, the Air Force Research Laboratory. The aircraft was maintained and operated by Calspan Corporation of Buffalo New York, under contract to the USAF. This T-33A was modified in the late 1950s for flight controls investigations and simulating the flight characteristics of other aircraft designs. Schedule permitting, the aircraft was sometimes made available for contractor or foreign government evaluations, usually to correct anomalies found in new aircraft designs. The aircraft was also used by both the USAF and US Navy test pilot schools as part of their flight controls evaluation curriculum. This is where I first encountered the jet. The F-94B nose houses computer units interfaced to the aircraft flight controls. The rear cockpit is modified with banks of controls to change the coefficients and variables of the flight control equations, thereby changing how the aircraft responds to control inputs. The Calspan safety pilot would occupy the rear seat while the research pilot or student would fly the aircraft from the front. The safety pilot could take control of the aircraft at any time using the basic T-33 flight controls. or if specified flight conditions were exceeded, usually yaw/pitch rates or Gs, the system would automatically kick off the variable stability control laws and revert to T-33 flight control operation. The aircraft has changed some over the years. During the 1960s, the aircraft tip tanks were modified to have the aft portion of the tanks act as clam shell speed brakes. This modification was later removed. In the late 60s/early 70s, the F-94 acquired rows of vents on each side to facilitate cooling as more computing power was added to the variable stability system. My TPS class team project was to investigate changing the roll axis of the aircraft through flight control changes and its effects on maneuverability. Most of the tests involved evaluating the ability to handle various target tracking scenarios. Lots of piccies… Ready for brake release... Returning to Eddie's Air Patch... A long pass down the Edwards Tower Fly-By Line... Nose-on view... Computers circa 1978... Some of the variable stability input controls in the rear cockpit Side-stick controller in the front cockpit. There's a center control stick as well. Nose detail in 1988 The stickers on the nose are from left to right, top to bottom: Swedish flight test center, IAI Kfir C2, NASA, USAF Test Pilot School, US Navy Test Pilot School, unidentified, SAAB JAS 39. The first and last are interesting in that the aircraft took part in flight controls development of the Gripen, yet in the following year, the Gripen would have the first of two mishaps attributed to Pilot Induced Oscillation (PIO) caused by flight control software issues. After the 1989 mishap, the NT-33A was again being used to investigate the cause and possible corrections to eliminate the PIO situation. The NT-33A was retired and put on display in the National Museum of the USAF in 1997 after many years of being the oldest aircraft in the USAF active inventory. When it went to the museum, it retained the dummy refueling probe used in one of its last research projects and remains there on display... Thanks for looking, Sven