When I took the HeliSIM default model for a “flight”, I was happy to find that the model flew and responded like a real helicopter. Anyone who is familiar with the physics behind helicopters knows that any attempt to model their behavior must be accurate. The interaction between a large number of variables and the resultant flying characteristics are complicated to say the least, but the HeliSIM default model captured my interest immediately. I very quickly noticed the most pronounced effects of main rotor torque and also realized that the required pedal inputs (that control the tail rotor) were accurate. Not content to fly the default model, I went through the list of available models and took each one for a “flight”. After loading and flying different models, I was especially excited by the high level of accuracy of the Bell 412 and I was instantly hooked.
High fidelity of the HeliSIM Bell 412 Model
I had flown a Bell 412 (a somewhat heavy, twin-turbine, four-bladed utility helicopter) more than twelve years ago and attempted to recall that experience as I exercised this model. If you relate different helicopters to cars that we all drive, I’d have to say that the Bell 412 is much like a mini-van. While it is not the fastest helicopter on the market and is limited by altitude and temperature, the Bell 412 will cruise quite comfortably and can carry an enormous interior and/or external payload.
As it happened, the visual database I was flying was a real-world location in the Salt Lake City area known as the Wasatch Mountains, an area that I am quite familiar with after living there for almost nine years. I positioned myself at a popular ski area parking lot at the top of Big Cottonwood canyon, pulled up into a hover, and then transitioned to forward flight. I barely cleared the rapidly rising terrain but had no hope of climbing up over the nearby rim of mountains at about 11,000 feet. I had the collective very nearly all the way up, but I was not climbing. So, I went back to the landing spot to see what was going on.
I poked around in the various default configurations of the Bell 412 in HeliSIM and found myself in the Helicopter menu where you specify features such as the aircraft’s weight and engine performance. I noticed that the aircraft was configured with a full fuel load, so I dropped the fuel load to about 20% and tried my takeoff again. Now, I had more collective margin at the hover, and, when I took off, the helicopter climbed much faster and easily cleared the 11,000 rim nearby.
Upon hearing my story of the fully fuel loaded Bell 412, a good friend of mine who flies for a Helicopter Emergency Medical Service (HEMS), or Air Ambulance company, in Salt Lake City was amazed by the accuracy of the HeliSIM model. Drawing on my friend’s extensive knowledge of the Bell 412, I spent the next few weeks tweaking a number of other performance characteristics in the model. For example, I tuned the landing skids to give me just the right amount of bounce and settle on landing. As I continued to fly and tweak the HeliSIM model, I began to think about how we could support a number of helicopter training areas including procedural or rehearsal device for active pilots.
Taking the Bell 412 demonstrator to I/ITSEC
As word spread about my work with the Bell 412 model, a decision was made to take the demonstrator to I/ITSEC 2009! The idea for the show was for me to be the primary demonstrator, and, as interested show-goers noticed our display, I would also coach them as they attempted to take the demonstrator for a “flight”. With only weeks to prepare, my new challenge was to get an elegant COTS software and hardware solution integrated in time for the show in December.
We immediately began work to customize the integration of our image generator Lyra and our flight model generated by HeliSIM. We also had our Content Creation folks start adding 3D models to selected areas in the database. By including geographically specific buildings and power poles with wires, the pylons and cables for several ski lifts, and a lush forest of individual trees and bushes covering the mountains, they transformed the database into a very rich, dense representation of an area I knew quite well. Then, we incorporated VAPS XT for the flight instruments and got word from our partner Ryan Aerospace, a vendor in Australia, that we could use their seat and pilot controls at the show.
To complete the demonstrator for I/ITSEC, we worked with our partners Christie so that we could integrate two of their projectors with a wide-screen display that was provided by Vutec. We also included Mersive’s distortion correction on the simulator to seamlessly blend the image from the two projectors into a gorgeous out-the-window scene.
On the show floor, both novices and some recent or active pilots flew the demonstrator. To our delight, show attendees were quick to understand the flight behavior of the device and experienced pilots indicated it was a great representation of a large, twin-engine, 4-bladed helicopter like a Bell 412! While the first takeoff was a bit shaky, these active pilots were quick to get a feel for the demonstrator and were able to perform a number of maneuvers with confidence and precision!
