S-Tec System Twenty/Thirty
Compare the S-Tec System Twenty/Thirty autopilots to your average disco-era autopilot and you'll see just how far electronics have come since the days when the only thing Gerald Ford got in the Oval Office was lost. What used to take a peck-basket full of components (and a part-time avionics technician to maintain) now fits, literally, in the palm of your hand.
Engineers will appreciate the efficient design of the new S-Tec systems — the System Twenty takes up no additional panel space — and pilots will enjoy the performance and value. Except for a tiny servo, the System Twenty is entirely contained in an S-Tec turn coordinator (TC). A knob in the upper left corner of the TC is the only necessary control.
Two AOPA staff members have recently had System Thirty units installed in their aircraft — one a Cessna 172N; the other, a Mooney M20E. Neither previously had an autopilot, although the Mooney still had its stock Positive Control pneumatic wing-leveling system. The PC was removed during the autopilot installation. Particularly for the Mooney, panel space was a premium. The Cessna's TC was clouded over and in need of an overhaul anyway, so it was a good time to add the autopilot capability.
The System Twenty is a single-axis rate-based autopilot, meaning that it gets all of its roll axis control inputs from the electric TC. Rate-based autopilots tend to be more stable and reliable than attitude-based models, which get their inputs from the attitude indicator.
If you can dial a telephone, you can operate a System Twenty. Push the button to turn on the roll stabilization mode, which lights the "ST" light-emitting diode (LED) on the TC's face. In that mode, the autopilot holds the wings level. Turn the knob left or right to induce a turn. Push the button again and the unit goes into the Heading Hold mode, lighting the "HD" LED. In the standard System Twenty this is the same as roll stabilization mode. But if you have a bug-equipped directional gyro or horizontal situation indicator with the correct electronic pickoffs, the autopilot will track the selected heading. S-Tec sells an optional DG with a bug. However, many other used DGs can fill the bill. Check with your local avionics shop.
A third push of the button lights the "LO" LED and activates the Nav/GPS Track feature in its low-sensitivity mode. Here it will follow a VOR course deviation indicator to stay on track. A fourth push of the button puts the unit into the high-sensitivity mode and lights the "HI" LED. This is an ideal mode for GPS course tracking. In the HI mode and when connected to a GPS, we watched the autopilot track the course dead on, carefully adjusting for crosswinds. Unlike more sophisticated and more expensive autopilots, the Twenty will not intercept a course. Before engaging the nav tracker, the pilot must manually (or using the Heading mode) maneuver the aircraft until the CDI is nearly centered.
Another push of the button takes you back to the roll-stabilization mode. Hold the button for two seconds to disconnect the autopilot. Most customers opt for a more conventional autopilot disconnect on the control yoke.
If you have a need for altitude hold, you can add an altitude button to the control yoke (or anywhere else that's convenient) and upgrade to the two-axis System Thirty. It operates identically to the System Twenty, except that when you push the altitude button, the blue "ALT" LED is lit to indicate that the autopilot will maintain the chosen altitude. The System Thirty requires a remote-mounted pitch computer and an absolute pressure transducer. The solid-state pressure transducer senses altitude changes without needing to be interfaced to the altimeter or attitude gyro. If the system senses a need for nose-up or -down trim, it lights the appropriate LED on the TC's face, prompting the pilot to move the trim wheel. In a sense, you become a manual pitch servo. There is no capability for vertical speed control or glideslope coupling. If you have such a need, S-Tec would be quite happy to sell you one of its more expensive autopilots.
Those in need of just an altitude-hold autopilot can purchase the stand-alone System Thirty ALT. It requires only one switch on the panel to turn the unit on. "Up" and "Down" annunciators built into the switch advise the pilot of the need to trim. The Thirty ALT can complement a roll-axis autopilot of any brand.
S-Tec lists the System Twenty for $4,495. You can upgrade a Twenty to a Thirty at any time for $2,795. An out-of-the-box System Thirty is $6,995, so you save about $300 by starting out with the more sophisticated unit, not to mention the additional installation time of having to open up the airplane again to add the altitude features. The System Thirty ALT lists for $3,295.
As you might expect of such a diminutive system, the weight penalty is small — about nine pounds for the two-axis system. The S-Tec TC is a bit longer than some TCs, so have your avionics shop check the space behind your panel for compatibility.
All in all, the System Twenty/Thirty is a tidy and efficient new building-block autopilot system that provides a great deal of value. It is ideal for lighter aircraft that are panel-space challenged, offering most of the prime features that pilots use day in and day out.
For more information, contact S-Tec Corporation, One S-Tec Way, Municipal Airport, Mineral Wells, Texas 76067-9236; telephone 940/325-9406, fax 940/325-3904; or visit the Web site ( www.s-tec.com). — Thomas B. Haines
Comm1-VFR Radio Simulator
In an industry that often seems flooded with multiple products serving the same purpose, E-Publishing Group has announced a unique, high-tech solution to an age-old problem — learning to communicate effectively on the radio. Comm1-VFR Radio Simulator is an interactive CD-ROM-based training device aimed at giving the inexperienced pilot the real-world radio experience that normally comes only after hours of expensive, and sometimes embarrassing, real-world trips.
The software took just a few clicks of the mouse before we were up and running on both Windows and Macintosh-based PCs. The interface consisted of three user-friendly windows: one containing an index of all the available lessons, one with a transcript of the selected lesson, and one for the interactive portions of the training. What truly makes this product unique, though, is the use of a miniature headset with working microphone.
In each section, after being presented with a particular lesson, you are asked to communicate just as if you were talking on a real unicom, approach, or tower frequency. You are taught how and where to find the appropriate frequencies; then, using industry-standard Bendix/King radios, you actually tune the necessary frequencies and make your announcements. Comm1 includes actual radio chatter, so be careful when you speak — it won't let you rudely transmit while others are trying to talk. In an effort to train you to include all of the necessary information in any transmission, Comm1 always presents you with several choices of sometimes verbose AIM-recommended dialogue. Make the correct selection by clicking on the virtual push-to-talk button (next to each choice) while making your announcement. The controller then responds with your next set of instructions.
Every lesson wraps up with a debriefing in which you get to replay your whole transmission and then compare it to that of a professional. Comm1 lessons in radio-speak begin with exercises on the phonetic alphabet and go on to cover more complicated communications, including towered airports, VFR flight following, and emergency communications.
While Comm1 is aimed at helping the low-time pilot to establish some level of confidence in how and what to say when talking to a controller or other pilots, it was clearly the opinion of those who tried the product at AOPA Expo that many veterans could benefit from spending some time behind the radio simulator.
Required hardware includes any SoundBlaster-compatible sound card, four-speed CD-ROM, and a computer with speaker and microphone. A headset will be included in the package for those ordering before December 31. After that, a headset will cost an additional $24.95. Future products will include a multiuser version for flight schools and an IFR version, to be dubbed Comm2. For all of Comm1's impressive interactivity, a function we would have really appreciated is some way to pause in the middle of a lesson without having to stop and restart that lesson from the beginning.
Comm1's single-user version will retail for $119 but is currently offered at an introductory rate of $99.95 until March 31. For more information, contact E-Publishing at 888/333-2855 or 301/620-9500 or visit the Web site ( www.e-publishing.com/comm1/). — David W. Weigelt
Briefly Noted
Having trouble maintaining altitude? Computer and Monitor Maintenance Inc., of Norcross, Georgia, has introduced the Altitude Tracking Module (ATM) for use as an altitude deviation alerter in nonpressurized general aviation aircraft. After reaching the desired altitude, the pilot presses a button that locks in the current altitude by sensing pressure. The $199.95 ATM visually alerts the pilot if he or she strays as little as 50 feet from the altitude initially set in the cigarette-pack-sized box. If that's too sensitive, the box can be set to alert at 100 feet. Since there is no aural warning, the unit must be kept in plain view by affixing it to the glareshield (far enough away from the compass to avoid magnetism) or instrument panel with hook-and-loop tape or other fasteners. To order, call 800/466-4411 or 770/662-5633. The ATM is also available through Sporty's Pilot Shop (800/SPORTYS). — Peter A. Bedell
Unless otherwise stated, products listed herein have not been evaluated by AOPA Pilot editors. AOPA assumes no responsibility for products or services listed or for claims or actions by manufacturers or vendors. However, members unable to get satisfaction regarding products listed should advise AOPA. To submit products for evaluation, contact: New Products Editor, AOPA Pilot, 421 Aviation Way, Frederick, Maryland 21701; telephone 301/695-2350. Links to all Web sites referenced in this issue can be found on AOPA Online ( www.aopa.org/pilot/links.shtml).
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