The Purpose of a ScreenSaver

Screensavers have actually been around long before Bill Gates conceived Windows first feasible operating system; even long before Microsoft bought the licensing rights from Apple for the Recycle Bin. As a matter of fact, the processors in my toddlers electronic toys today are more powerful than the what the average desktop computer was when screen savers first came on the scene.

The first screensavers were used on the 1979 Atari 400 and 800 computers to protect their monitors from the last image left on the screen from being burned into the monitors phosphor coating (hence the term, burn-in) permanently. These first screen savers merely performed simple full screen color changes which shifted the display contents periodically thereby not subjecting any one pixel or group of pixels to a steady electric current, which is essentially what alters the properties of the outer phosphor coating. This causation or neglect, depending on who your talking about, triggered the process which became known as, ‘burn-in’. Once burn-in occurred, the damage was permanent; the ghostly image would be forever impregnated onto the screen regardless of what the computer loaded to it there after.

The burn-in problem was thought to be isolated to ‘CRT’s only’ since the giant phosphor coated vacuum tube was susceptible to such maladies. As more and more CRT’s began to get phased out with the advent of the thinner more attractive flat screen LED monitors, everyone was convinced the burn-in malady that once affected their computer monitors would now be a thing of the past. LED’s and plasma screens after all, utilize an entirely different technology to produce an image, so how could they possibly be affected by phosphor burn-in anymore, right? Oddly enough, as more and more consumers bought LED monitors the influx of complaints seem to grow in proportion to the number of consumers who owned them. Many of the Internets computer guru’s were getting swamped with questions and concerns about the infamous ‘burn-in’ problem again, except on their new allegedly impervious LED flat screens…how could this be? The problem was an unpleasant familiar one — ghostly images on computer monitors…hmmm.
It didn’t require an engineer to determine that the LED monitors were experiencing similar phenomenon, but it did require engineers to make the determination that it was not the same problem. It seems that LED’s were just as susceptible to the same monitor abuse that the antiquated CRT’s were. Leaving the monitors on over-night for instance, regardless of make or model, caused what appeared to be, the infamous ‘burn-in’. But was it actually ‘burn-in’? And if it was ‘burn-in’, that meant there was hope for screensavers…this meant that screensavers had a renewed purpose again.

F-15 Eagle USAF jet fighter

During the mid-1960’s, US intelligence sources indicated the Soviet Union developed a large fighter which appeared could easily dominate the USAF’s short-range capable F-4 Phantom. In response, the Air Force recruited Boeing (former McDonnell Douglas) to design an air superiority fighter over the Soviet’s MIG-25 Foxbat, a feared high altitude fighter. Although larger and heavier than what the USAF was looking for, the F-15 would go on to prove its maneuvering capabilities even out-performed its designers expectations. It was deployed for service in July 1972, and is expected to remain an integral part of the United States arsenal well into 2025.

 

As it turned out, the Soviets MIG-25’s huge tail-planes and vertical stabilizers, imagery acquired via surveillance; were the USAF’s primary concern. They were intentionally designed larger than normal to overcome inertia coupling, a dangerous phenomenon; not to contribute to a superior maneuverable aircraft design as intelligence sources first indicated. Contrary to what everyone in the West thought, the all-weather F-15 tactical fighter would go on to reclaim air superiority for the United States and her allies. The MIG-25 was designed to be only a high speed Interceptor and not a highly maneuverable fighter after all.

The F-15’s new twin Pratt & Whitney F100 axial-flow turbo fan engines with twin afterburners were designed specifically to generate the needed power to meet or exceed the Air Forces required combat thrust to weight ratio of 1:1. Simply put, the engines thrust output exceeded the aircrafts weight allowing it to impressively accelerate even whilst in a vertical climb. There was not a critic to be found. The clear need for a new fighter to overcome the close-range limitations of the Phantom while still retaining long-range air superiority had arrived in one beautiful package…the F-15 Eagle. Ironically, the design which led to the Navy’s own impressive F-14 Tomcat was rejected by the Air Force in lieu of the F-15. The F-15 would end up being the preferred strike fighter by Israeli and Japanese customers with the development of the redesigned F-15E Strike Eagle which would go on to replace the FB-111.

The standard M61 Vulcan gun was retained due to development problems with the new replacement cannon they had in mind. The F-4’s four Sparrow missiles were retained as well. The fuselage was flat providing additional lifting surface. The cockpit canopy provided clear forward vision. The F-15’s flight control and weapons systems are controlled by computers that will effectively allow the pilot to easily concentrate on maneuvering the jet during combat engagements with the enemy while the weapons computer system automatically interprets enemy threats and deployment of the necessary counter-measures

Other improvements have made it possible to carry an additional 2000 lbs of internal fuel, as well as two external fuel tanks each capable of carrying an additional 750 lbs of fuel. The additional 3500 lbs of fuel increases the take-off weight to 68,000 lbs. 

An ‘Identification, friend or foe’ multi-mission avionics system includes a heads-up display (HUD), inertial guidance system (INS), UHF communications, tactical air navigation (TACAN),  an upgraded central computer; Programmable Armament Control allowing for advanced versions of the AIM-7, AIM-9, and AIM-120A missiles; and an expanded Tactical Electronic Warfare System that provides improvements to the ALR-56C radar warning receiver and ALQ-135 countermeasure set. The price-less headset clearly displays weapon systems, enemy targets, and a highly sophisticated APG-63 \70 Pulse-Doppler Radar system can distinguish high speed, high-flying, low-flying targets up to 120 miles away from any ground clutter down to tree-top levels. The pilot maintains clear visual through a large canopy while easily surveying enemy targets and weapons systems with a quick glance on his head-set without needing to look down at the instrument panel.

SPECIFICATIONS

Cost: $29, 000,000 each

Crew: 1
Length: 63 ft 9 in (19.43 m)
Wingspan: 42 ft 10 in (13.05 m)
Height: 18 ft 6 in (5.63 m)
Wing area: 608 ft² (56.5 m²)
Airfoil: NACA 64A006.6 root, NACA 64A203 tip
Empty weight: 28,000 lb (12,700 kg)
Loaded weight: 44,500 lb (20,200 kg)
Max takeoff weight: 68,000 lb (30,845 kg)
Powerplant: 2-Pratt & Whitney F100 afterburning turbofans
Dry thrust: 17,450 lbf (77.62 kN) each
Thrust with afterburner: 25,000 lbf for -220; 29,000 lbf for -229 (111.2 kN for -220; 129.0 kN for -229) each

Maximum speed:
High altitude: Mach 2.5+ (1,650 mph, 2,660 km/h)
Low altitude: Mach 1.2 (900 mph, 1,450 km/h)
Combat radius: 1,061 nmi (1,222 mi, 1,967 km) for interdiction mission
Ferry range: 3,450 mi (3,000 nmi, 5,550 km) with conformal fuel tanks and three external fuel tanks
Service ceiling: 65,000 ft (20,000 m)
Rate of climb: >50,000 ft/min (254 m/s)
Wing loading: 73.1 lb/ft² (358 kg/m²)
Thrust/weight: 1.12 (-220), 1.30 (-229)

Guns:
1× internally mounted 20 mm (0.787 in) M61A1 gatling gun, 940 rounds
Hardpoints: four wing, four fuselage, two wing stations, centerline station, optional fuselage pylons with a capacity of 16,000 lb (7,300 kg),

Missiles:
AIM-7F Sparrow
AIM-120 AMRAAM
AIM-9 Sidewinders
Avionics

Radar:
Raytheon AN/APG-63 or AN/APG-70 or
Although several F-15C aircraft were produced with APG-70 radar

Raytheon AN/APG-63(V)2 Active Electronically Scanned Array (AESA) Both active AF and ANG F-15Cs will receive another (up to) 48 V3 units between 2009-2015, over the existing 19 aircraft.[68]

Countermeasures:
AN/APX-76 or AN/APX-119 Identify Friend/Foe (IFF) interrogator
Magnavox AN/ALQ-128 Electronic Warfare Warning Set (EWWS) -part of Tactical Electronic Warfare Systems (TEWS)
Loral AN/ALR-56 Radar Warning Receiver (RWR)-part of Tactical Electronic Warfare Systems (TEWS)
Northrop ALQ-135 Internal Countermeasures System (ICS) – part of Tactical Electronic Warfare Systems (TEWS)
AN/ALE-45 chaff/flare dispensers

Engines:
Pratt & Whitney F100 turbofan engines

Others:
Joint Helmet Mounted Cueing System[68]
MXU-648 Cargo/Travel Pod – to carry personal belongings, and small pieces of maintenance equipment