UBM Tech
UBM Tech

Aircraft simulator challenges at the Cradle of Aviation Museum

-July 23, 2012

I visited one of my favorite Long Island places last week, the Cradle of Aviation Museum, in Garden City, NY

The museum has its own Director of Education, Jennifer Baxmeyer who is intimately involved in the STEM programs here. The day after I visited there, NASA representatives (including former astronauts) came to speak to young students.

On July 11th, Major Heather “Lucky” Penney told her story as a 9/11 First Responder and as an F-16 Pilot in Iraq.

On Wednesday, August 1, 2012 at 10:00 AM, Captain Barrington Irving will address the incoming freshman of the Westbury STEM Magnet Academy at the Cradle. Captain Irving is the youngest person and first black pilot in history to fly solo around the world. He will be discussing his journey, passion for flying and his goal of encouraging young people to explore career opportunities in the field of aviation.

These are just some of the amazing events happening here! Stop by and visit the museum and if you live on Long Island and are retired, please do consider volunteering to help in the restoration and design of some of these excellent projects for display or even to be a technical tour guide there. There’s lots of work to be done and they could use your help.

The Simulators

I’m like a “kid in a candy store” when I’m there. So many aircraft, space vehicles and actual flight simulators that you can use on appointed days! Some are good graphics simulators, but there are a few are real motion simulators and one is a full-motion simulator that you fly!

The simulators are only part of this story. The engineers that volunteer their time at the museum to restore and modify electronic designs are the “heart” of the story here. There are retired electronics and mechanical engineers as well as aircraft engineers and FAA certified flight instructors that volunteer their time to make this an exciting place for the young and the old.

Mort Hans and Arthur Glazar (Arthur wrote the article in EDN on the Analog Computer) welcomed me and my “photographer” wife Loretta to the Cradle with the intention of discussing the simulators at the museum and how they have been modified to work best for museum visitors.

Fig 1: Steve Taranovich, Mort Hans and Arthur Glazar discuss the tour of the simulators at the museum

One flight simulator being readied and re-designed by the volunteers Mort and Art, is anATC-710These simulators use analog and hybrid computer techniques to drive indicators which are replicas of the flight instrumentation found in a typical IFR-equipped light aircraft. This design approach offers an excellent price/performance ratio to pilots desiring to improve their IFR skills with an FAA-approved flight simulator.

Figure 2: ATC-710 Personal Flight Simulator Instrument Panel


The following is a partial schematic in Figure 3 that will help describe their strategy to interface the existing ATC hardware with a PC to create the basis for a modern simulator exhibit for the museum.

In the ATC simulator, all analog signals are generated by potentiometers mechanically linked to operator input controls. For example, Figure  schematic shows input pins  along the left-hand side labeled AILERON POT, PITCH POT, ELEV POT and THROTTLE.  These are all signals taken from the wiper arms of the various potentiometers. Typically, the potentiometer ends are biased with plus and minus 15 VDC, so that the output taken from the wiper could swing through the full voltage 30-volt range if its rotation were not mechanically restricted.

Figure 3: Schematic of the ATC-710 simulator

Their first consideration then, was to convert all such ATC analog signal voltages into signals that swing from zero to +5 VDC for application to the PC circuits. They've been able to do this with a simple 4-resistor network for each analog signal.  A similar approach was used for non-analog signals which represent commands from switches and pushbuttons, such as MASTER SWITCH ON/OFF, ENGINE START, GEAR UP/DOWN, etc.

The interface hardware between these "level-shifted" ATC signals and the PC consists of modified gaming joysticks. Like the ATC, joysticks also use potentiometers mechanically linked to a 2 or 3-axis control stick to generate X-Y-Z signals. By removing the potentiometers and mechanical parts from the joysticks, they were able to substitute their "level-shifted" ATC signals as inputs, and the joystick internal circuits convert them to USB format for direct input to a PC. See Figure 4.

Figure 4: The ATC-710 flight simulator working block diagram shows the modifications made by Art and Mort to convert the potentiometers through level shifters to the USB bus to the PC

Figure 5: Master designer Mort at the workbench with the ATC

Figure 6: An analog engineer’s RAM memory to scratch out some ideas

The whole process is shown in Figure 3 hand-drawn block diagram/schematic.

The rest is up to the Flight Simulator software. It will process the USB input data and translate it into aircraft dynamics and appropriate scenery for visual display on a suitable monitor. 

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