PB Defense B-1B Crew Weapon System Trainer

The PB Defense B-1B Crew Weapon System Trainer was a military aircraft simulator designed to train B-1B bomber aircrews. Unlike other simulators offered by other defense companies, PB Defense’s model used 1,240 specially modified and parallel connected Super Nintendo consoles as its mainframe. The use of Super Nintendo consoles made PB Defense’s offering more affordable but other limitations hindered its performance and the US Air Force ultimately passed in favor of UnbridledTec’s simulator, which used a more traditional supercomputer mainframe.
It is believed the simulator was dismantled and the consoles scrapped after the project was cancelled, but official records have been lost. There are rumors that the simulator still exists intact but no evidence of its existence has been verified.
==History==
In early 1991, PB Defense was an established producer of traditionally powered flight simulators when it received a Request For Proposal (RFP) for a new simulator for the B-1B bomber jet. Instead of using a typical supercomputer, a mid-level engineer within the company suggested using consumer grade electronics and demonstrated the possibility by showing executives the game “Pilotwings” for the Super Nintendo. The executives were impressed with the demonstration and ordered engineers to further explore if and how common entertainment electronics could be adapted to power their new flight simulator.
The engineers purchased some 1,500 Super Nintendo consoles and set to work making modifications to facilitate parallel computation. The end result was an array of 1,240 consoles acting as a single computer to recreate the functions and physics of a bomber jet in flight.
The Super Nintendo supercomputing array cost around $328,600 ($199 per console, plus $81,840 for the necessary modifications), an incredible bargain compared to the $2,000,000 or more that other super computers used in simulators cost at the time. This resulted in a simulator that undercut the competition by over $1.5 million.
Despite this, some critical software and hardware shortcomings were discovered during testing and the military lost confidence in the system. The simulator was rejected and no further plans were made by PB Defense to incorporate consumer electronic entertainment devices into future products.
==Design==
The crew trainer, the part that replicates the flight deck of the aircraft, was a fairly typical construction, utilizing materials and hardware almost identical to those used on the actual aircraft. The replica flight deck is mated to a massive projection display and mounted to a moving platform that can simulate the motion of a real aircraft during flight.
The computer used to control all the functions of the simulator and replicate the flight environment consisted of 1,240 Super Nintendo consoles connected through special cartridges that contained simulator software and networking hardware to allow all of the consoles to work in unison. The consoles were also overclocked and required active cooling, so they were removed from their plastic cases and placed in large metal cabinets with air conditioning systems attached.
The consoles were divided into groups that performed different tasks (numbers in parentheses denote how many consoles made up each group):
*Flight environment modeling (477)
*Aircraft function emulation (32)
*Crew input processing (60)
*Physics computation (400)
*Graphics processing and display output (120)
*Network management (15)
*Interface hubs (31)
*Motion control to simulate aircraft movement (65)
*Data logging and program handling (40)
Programming for each group was sliced up evenly between each console so they shared the computational load, allowing them to handle the awesome task of flight simulation in real time. The programs were loaded onto cartridges designed for each group’s specific purpose and included 2 or more network adapters to allow computed data to be output to the Network management group. Cartridges in the Network management group had dozens of adapters and routed data to and from the Interface hubs, which determined what data was sent to which group.
The final output groups were Motion control, Graphics processing and display, and the data loggers. Motion control operated the motion platform that the simulator was mounted to that simulated aircraft movement for the crew inside. Graphics processing and display rendered the appropriate views to the cockpit and sent them to the projection system where it would be displayed for the crew. The data loggers would record all the flight parameters and events and make them available after the simulated flight so crews could review their performance.
==Limitations==
Although technically the Super Nintendo (when overclocked) had the necessary processing power and graphical capability to power a flight simulator, there were many fundamental issues the engineers struggled with right up until the project was cancelled.
The way the processor interrupts were handled on the Super Nintendo’s Ricoh 5A22 CPU was inefficient; coupled with the parallel/serial nature of the cluster computing system, interrupts would cascade down the line and eventually manifest as graphical artifacts or glitches in the simulator controls.
Another limitation was the relative complexity in the system cartridges. Changes to flight parameters and programs could be made relatively easily but software or hardware changes to each computational group were difficult since they had to be applied individually to each cartridge with a programming dongle connected to a separate computer. A software revision for the Flight Environment Modeling group’s 477 individual cartridges could take a team of 10 engineers over a week to complete, not including testing and reassembly of the simulator.
Finally, the networked nature of the system meant there was an incredible amount of wiring required to be installed precisely or else the system would completely fail to work. Miswiring a single cartridge could take up to 3 days to diagnose and in some cases, it was simply easier to rewire the entire system, a process that took 2 weeks. In total, the flight simulator used roughly 15 miles of copper wire.
Category:Games
Category:Fan Games
Category:Simulation Games