Once this was done the process had to be repeated using another pair of master/slave station signals. The Chart had different colored parabolas for each pair of stations. With practice a fix could be determined in about three minutes. The minimum error for navigating the 1400 miles to Japan from Tinian was about 28 miles. With two successive fixes ground speed, drift, and ETA could be determined. As more islands were made available a third pair of stations could be added to improve fix accuracy. The relative simplicity of LORAN and the fact that it could be used regardless of weather made it invaluable until landfall on Japan enabled airborne radar to make a better fix. Fuel savings made possible by LORAN probably saved more lives than did the capture of Iwo Jima.

For some unknown reason the Japanese either never tried or failed to jam any of the LORAN systems. Loran - A as this All airline pilot training, commercial pilot training, air force pilot training, fighter pilot training, pilot training schools, flight training schools, flight attendant training, helicopter flight training, accelerated flight training, airline flight training, flight training florida, flight attendant training schools, instrument flight training, cpl flight flying school training training, flight training simulator, flight training academy, atp flight training, helicopter flight training schools, california flight training, professional flight training, data flight training, orlando flight training, corporate flight attendant training, flight nurse training, warrant officer flight training, flight training device, lufthansa flight training, flight training san diego, alien alien flight flight training, military pilot training, sport pilot training and private pilot training.

In the late 1980s LORAN - A was being replaced by LORAN - C. Loran - C used a chain of stations and a Loran receiver that programmed the station components of the chain so that multiple LOPs (lines of position) could be simultaneously recreived and translated into longitude and latitude coordinates. Loran -C can compute from your departure point or your present position to a destination a direct bearing, distance, ground speed, and ETA.

The low frequency of Loran removes the VOR line-of-sight problem. The entire U.S. is covered by 23 stations that give an average accuracy of less than 1/8 mile. There are limitations depending on the data base used. If your data base does not have terrain elevations, Loran can fly you a direct route from CCR to Merced via Mt. Diablo. Class C and B airspace may not be included or kept up to date. Your Loran may die of a voltage spike to its power transistor. Use it and trust its accuracy but don't depend on its ability to always be available. Pilotage is the only navigational system that doesn't quit until you do.

On the West Coast we have the 9940 chain. The master is at Fallon Nevada with three slaves stations at George (Central Washington State), Searchlight (Death Valley, and Middleton ( Between Calastoga and Clear Lake). The 9940 designation has to do with the total number of microseconds (99400)it takes for a cycle of signals to go between the stations. At 99400 microseconds the data of the Loran receiver clock is updated about 15 times a second. Your Loran receiver uses the time difference of the signals received from the master and each of the three slaves to get three simultaneous LOPs (Lines of position). As you fly beyond one chain you are going to be in range of another. Just how the change will be made, manual or automatic, depends on the sophistication of your Loran.

One of the displays on the Loran is a Course Deviation Indicator or CDI. More expensive displays may have a moving map indicator. These displays will indicate which direction and how far off the straight line course original selected you have flown. Some displays will give you headings required to establish yourself back on course. Some data bases have about 30,000 waypoints so that you do not need to enter in longitude and latitude. Longitude and latitude does work. Over ten years ago I figured the longitude and latitude of Medford, Oregon and put it into a Loran when leaving Nut Tree. It read 1/2 mile when we were on short final. Loran - C is operated by the Coast Guard at a price of $25 million a year. With the advent of GPS it is not long for this world.

How do I know all this? I taught LORAN-A in India and on Tinian to replacement crews as they arrived from the States. I was assigned to the Wing Training School of the 58th Bomb Wing of the 20th Air Force. (B-29s)

ELVIS
There is a whole new world of aerospace technologies waiting in the wings. My older son was project director for such a program called ELVIS (Enhanced Linked Virtual Information System) for the Military. A computer screen on the ground or in the air will be able to provide every pilot with an all seeing eye of any selected airspace or route in real time. Terrain and weather overlays in three dimensions with all or selected traffic will utilize GPS transmitted information from all aircraft much as does a transponder. You can expect to fly with a moving map showing on a heads-up display. It’s coming soon.

The operational version runs on Unix servers at DoD commands and supports any Java-friendly or HTML-friendly client computer. Positional data is fed by a variety of sensors/sources, including GPS and radar surveillance, etc. ELVIS allows remote users to reach into tactical databases and pull time-critical data of interest.

ELVIS is currently installed at numerous DoD shore-based facilities and afloat platforms. Many new capabilities are completed (or in progress) which allow the tactical planners to expand their access beyond positional data to unit schedules, readiness, maintenance status, and planned activities.

SpaceShipOne
Emailed to me but no credits given….Gene Whitt

I just had the extreme pleasure of speaking with Mike Melvill yesterday, the pilot of SpaceShipOne's first two flights above the Karman line of 100 km.MSL, and with his wife. He gave a 45 minute presentation to the Aircraft Owners and Pilots Association conference in Long Beach on Thursday, and got a several-minute standing ovation. I was able to speak with him for a short while after his talk.

Since he was speaking to pilots, he didn't have to translate for the "general public" or pull many punches. He spent almost half of his time going over the flight controls and the entire cockpit layout inside of Space Ship One, explaining how it is flown. I think this is the first time this has been explained publicly in such detail, and it was amazing.

There are actually four separate flight regimes, and each is flown differently. Just after launch, it flies like a Piper Cub, using a joystick and rudder pedals with mechanical linkages to the controls (no hydraulic assists). When it goes supersonic, the aerodynamic forces are too high to be able to move the stick, and the controls are subject to flutter. So they use an electrically powered trim system, flown using the "top hat" switch on the joystick and a couple of grips on the arm rest of the pilot's seat. (There are backup switches to the left of the instrument panel, which had to be used on one flight.) This moves the entire horizontal stabilizers, not just the elevons on the trailing edges. Eventually, they get high enough and the air gets thin enough that they can again use manual controls, although the response is totally different than lower down. But that goes away as they exit the atmosphere; the Reaction Control System nozzles are then used for maneuvering in space.

Coming back down, the pilot has to reverse the sequence. There is no automated switchover of control systems; the pilot has to remember to move from one system to the next at the right times. The rudder pedals are not linked. Each controls one of the two vertical stabilizer rudders separately. You can push both rudder pedals at the same time, and get a fairly effective speed brake, with both rudders canted outward. Push both fully forward and they engage the wheel brakes. But these are not very effective and are only really useful for steering input during rollout. The real brake is on the nose skid: a piece of maple wood, with the grain aligned down the centerline of the airplane. He said it was the most effective braking material they could find.Stephen, we talked about G forces on Tuesday, and I got some of it wrong. He says that he gets hit with about 3Gs kicking him backwards as soon as he lights the rocket motor. He's supersonic within about 9 seconds later. But he immediately starts to pull up into an almost vertical climb. So he also gets over 4.3Gs pushing him down into his seat just from that maneuver. The combined force is "very stressful" and Mike says it's "important not to black out" at that point. He's going 1880 knots straight up within 70 seconds. On re-entry, the aircraft goes from being absolutely silent while in space to generating a deafening roar as it hits the atmosphere again. He's going about Mach 3.2 by that time, and has to survive about 5.5Gs for over 30 seconds, and lesser G forces for longer than that, as it slows back down. It sounds really intense, both as he explains it and on the radio.

A couple of interesting side notes: SpaceShipOne has a standard "N" registration number; but it is licensed as an experimental "glider". Apparently there was a huge bureaucratic hassle trying to license it as a rocket powered spacecraft, which they just sidestepped by calling it a glider. I asked him if it had a yaw string; he laughed and said that would have burned off. By the way, the registration number is N32F, where 32 is the number of Feet in 100km. (White Knight is N318SL - Burt Rutan's 318th design.)

Mike says that the flight director system (called a TINU) was developed completely in-house by a couple of 28-year-old programmers, and is absolutely fantastic to fly. That's why they don't need a yaw string. But I had heard over the radio that Brian Binnie had re-booted the TINU just before the landing approach during the X2 flight, and it took quite a while for it to come back up. So I asked Mike what that was about. He says that during re-entry, the TINU loses its GPS lock. So it keeps trying to go back to catch up, re-interpolate and compensate for the missing data, and this keeps it a little behind in its actual position calculations.

The pilot has no straight-ahead vision at all, so they have a real issue landing: they can't see the runway! The way they do it is to fly directly down the runway at 9000 feet; then they do a (military style) break and fly a full 360 degree pattern right to the landing. The TINU gives the pilot a "blue line" to follow and a target airspeed (which produces a given rate of descent). If the pilot follows the blue line, right to the break point and through the two 180 degree turns, it will put him right onto the runway at what ever touchdown point he selects. But the TINU has to be absolutely current when this is going on. So at something above 15,000 feet they reboot the TINU and get it re-synched with the GPS satellites again before setting up for the landing!

He also talked in detail about the rocket motor, and had photos of its insides after firing. The nozzle throat actually ablates as the motor burns, enlarging the interior throat diameter as the burn progresses. He described the problem they had on the June 21 flight: The rocket motor nozzle was skewed by about Ѕ degree to one side. This generated a surprisingly high lateral torque trying to turn the aircraft. If it had been up or down pitch rather than lateral, the controls could have handled it; but the lateral yawing forces were too great for Mike to compensate as the atmosphere thinned. The result was that he was pretty far off course. Mike says he reached apogee, rolled the spacecraft over, and was surprised to see the Palmdale VOR directly beneath him. That was 30 miles away from Mojave and a long glide home. He says its amazing how fast a relatively small deviation can produce large distances when you're going Mach 3!

For one of the static burn tests, they had fire and safety crews all standing a mile away, ready to duck if anything went wrong. In the middle of the test, Mike and Burt Rutan walked up to the front of the motor assembly and felt the pressure vessel that contains the N2O. Mike knew he was going to have this same thing strapped onto his back soon, anyway, and he wanted to know how much it vibrated, how hot it got, and how loud it was. It was deafening, literally. It turns out that, with the nozzles they use at high altitudes, it's actually not that noisy inside the spacecraft. But he still wears hearing protection.

Scaled Composites seem to have fabricated quite a bit of the rocket motor themselves, including the N2O tank (which is also the structural core of the spacecraft) and the nozzle casings. It would be interesting to hear from Michael's friend exactly what parts SpaceDev designed and what they manufactured.

Continued on Page Notes from digital recorder