June 1, 2001
Julie K. Boatman
With so many modifications to aircraft available to help you pursue higher and faster performance, it's refreshing to explore what you can do to make the bottom of the flight envelope a more pleasant experience.
Vortex generators (VGs) are well known in twin-engine circles, where they add so much controllability at slow speeds that V MC (minimum control airspeed) can be reduced substantially — greatly increasing safety. What VGs can do for single-engine airplanes isn't so immediately apparent. However, as it turns out, VGs can enhance safety in singles as well as twins.
Micro Aerodynamics, of Anacortes, Washington, recently certified vortex generators for Cessna 172s, 175s, and 182s. We flew a 182S before and after installation of the VGs during this spring's Sun 'n Fun EAA Fly-In in Florida, and we found that the VGs made a noticeable difference in the way the airplane handled at lower airspeeds.
The stock airplane delivered a flaps-up, power-off stall speed of 43 KIAS, and at the stall break the left wing dropped a few degrees. Power off with full flaps, the 182 stalled at 36 KIAS, right at the bottom of the white arc as promised. The VGs knocked three knots off both figures, giving a flaps-up stall speed of 40 KIAS — and 33 KIAS with flaps down — in this specific aircraft. Of course, at these speeds, the instrument tells some half-truths: The calibrated airspeed is 62 knots at 55 knots indicated, and it is 51 knots at 40 knots indicated. But, in relative terms, the VGs allowed the airplane to slow down substantially.
It should be noted that the change in stall speeds we saw nearly matched Micro Aerodynamics' claims. While it advertises 8 percent, we saw 6.9 percent with the flaps up, and 8.3 percent with the flaps down — trusting the airspeed indicator, of course.
However, the big story isn't strictly in the numbers but in how the VGs make the airplane feel. From early flight training, pilots practice flying around with the horn a-blarin' to grow accustomed to the soft feel of the controls at slower airspeeds. This mushy feeling derives from the disruption of airflow over the control surfaces when the airflow begins to detach as the wing approaches a stall. VGs — small vertical tabs placed at particular angles and locations, typically on top of the wings and vertical stabilizer — energize the airflow and keep it attached to the wing farther aft, increasing control response. In addition to the wing and vertical stabilizer mounts, Micro Aerodynamics' VGs are also installed underneath the horizontal stabilizer.
With the VGs installed, we flew the airplane around, stall horn complaining, at 1.3 and 1.1 V S and V SO. The control response felt significantly more positive, and turns to the left and right were made with less rudder input and more pilot confidence. Another level of the 182's new poise was displayed on landing. We made the approach at 55 KIAS, and came over the fence at 50 KIAS. It was a solid landing, but a very short one with good control throughout.
With the unmodified airplane, we also did a test climb from 1,000 to 5,000 feet msl to establish basic performance figures, and to see whether the VGs caused the 182 to suffer in the climb, typically one of the model's finest moments. A speed run also set guidelines for pilots who are concerned about losing precious knots. In both tests, the VGs demonstrated only a slight reduction in performance, 1 percent or less. Of course, even this change may have been attributable to the difference a day makes on environmental conditions — though the temperature was constant — and pilot ability.
If you fly in and out of short strips, or desire more responsive control feel at slower airspeeds, the Micro Aerodynamics vortex generators are worth considering. Kits for other aircraft are available, and the VGs can be painted to match your airplane. The Cessna 182 package costs $1,450, plus 8 hours' installation by your local maintenance facility. For more information, contact Micro Aerodynamics, 4000 Airport Road, Suite D, Anacortes, Washington 98221; telephone 800/677-2370 or 360/293-8082; fax 360/293-5499; or visit the Web site ( www.microaero.com).
Champion Aviation's new Velocity line of dry air pumps provide a visual indication of the pump's internal condition and remaining service life. A three-eighths-inch plug can be removed to allow a visual inspection of the pump shaft, and a patent-pending wear indicator port shows when vane wear requires pump replacement.
The pumps, with traditional carbon shafts and vanes, have other features designed to improve pump life, explained John Herman, Champion's regional marketing manager. For example, the rotor is designed to reduce damage from foreign objects and prevent vanes from sticking. Herman suggests an initial inspection at 600 hours, and then at every 100-hour or annual inspection thereafter.
The FAA has issued parts manufacturer approval for six Velocity dry air pump models covering most standard, high-performance, and high-load (deice boots, cabin door seals, gyroscopic instruments) applications. The pumps are available now. For more information, call Champion Aviation at 864/843-1162; fax 864/843-5414; or visit the Web site ( www.championaviation.com). — Michael P. Collins
Music in the cockpit sounds like a good idea, and, yes, that is a pun, sort of. But in most cases it's more a nuisance than not, at least until now. With the advent of its PMA7000MS-CD audio panel/CD player, PS Engineering has finally made it convenient to listen to tunes while flying.
In each of the two airplanes that I have owned I have installed PS Engineering audio panel/intercom combinations because I like the company's auto-squelch capabilities and the innovative nature of its engineering. In both cases, I had music inputs installed front and back so that pilot and copilot could listen to the same music or different music from those in the back. And in both airplanes, I used the music inputs exactly twice each. Bringing along cassettes or CDs and a portable player with batteries and cables to stretch to the jacks was, frankly, a pain.
But with the new CD version of the audio panel and intercom, you can leave the portable players, batteries, and cables at home. Just bring your favorite CDs — or better yet, leave them in the airplane, since, unlike cassettes, they won't be damaged by heat.
Gulf Coast Avionics in Lakeland, Florida, installed my PMA7000MS-CD audio panel, a slide-in replacement for the PMA7000 audio panel. The new version eliminates the mic selector knob in favor of buttons and loses the ADF and DME buttons, which are of little value these days. The inputs for those two systems are still there and you can swap buttons out if you need to listen to the ADF or DME. The changes allow room on the audio panel for two buttons to control the CD player. On the top row is the stop/eject button. On the bottom row is a button that starts the CD and, by holding it down, allows you to skip to the next track or to hear an intro for each track until you find your favorite.
The CD player itself, which has received TSO approval, can be mounted anywhere in the panel. I put mine over on the right side. Just slip a disk in, hit the play button, and start swaying to the tunes. You'll want stereo headsets to get maximum enjoyment from the system. The resulting sound is very good with no tendency to skip, even in turbulence. Whenever a radio call comes in or whenever anyone speaks, the music can be automatically muted. The tunes return to the normal volume once the conversation is over. Or you can hit the ICS button to go into "karaoke" mode, which eliminates the mute. Karaoke mode is the best choice at cruise, but you may want the mute on during climb and descent.
Only a couple of wires connect the CD player to the audio panel, so extra installation expense is minimized.
Like the rest of the PS Engineering audio panels, the PMA7000MS includes many features pilots have come to expect, including split com capability, allowing pilot and copilot to talk at the same time on different radios, and full duplex capability to support in-flight telephones, such as AirCell. Marker beacon receivers are optional. In addition, the pilot can choose to be isolated without music from others on board. Or, with "Crew" selected, front seaters can converse without disturbing those in the back and vice versa.
Minimum advertised price for the PMA7000MS-CD is $1,995. An optional digital recording system for recording ATC clearances is $129.95. Those who want a CD player and intercom, but don't need an audio panel, can try the company's PCD 7100 (see " Pilot Products," March Pilot). For more information, contact PS Engineering, 9800 Martel Road, Lenoir City, Tennessee 37772; telephone 865/988-9800; fax 865/988-6619; or visit the Web site ( www.ps-engineering.com). — Thomas B. Haines
Rotorcraft Enterprises offers auxiliary power units for general aviation aircraft. The Start Pac comes in three different models, with Model 1300 suitable for aircraft with engines up to 700 horsepower. The units are completely self-contained, and the 1300 delivers 24-volt power for starting an aircraft or providing additional ground power. The 1300 weighs 41 pounds and takes less than two hours to recharge from empty. The battery is maintenance free and is replaceable for approximately one-quarter the cost of the original unit. A charger, sold separately in 110- and 220-volt units, and international voltages, replenishes the Start Pac.
The Model 1300 Start Pac retails for $1,250. For more information, contact Rotorcraft Enterprises, Post Office Box 3068, Wickenburg, Arizona 85358; telephone 520/684-5442; fax 520/684-8970; or visit the Web site ( www.startpac.com).
Honeywell Bendix/King has announced a new electronic HSI for general aviation aircraft. The Bendix/King KI 825 is a compact, single-box system that combines traditional heading and navigation functions with mapping on a bright active-matrix LCD display. The unit fits in a 3-inch instrument slot. "This has been a hot item," said Dan Barks, director of business and general aviation marketing for Bendix/King.
The new EHSI will be able to display traffic information from TCAS, the Goodrich SkyWatch system, or Bendix/King's own traffic detection system, which is part of the IHAS 8000 integrated hazard avoidance system. The KI 825 will be available in late 2001 and will sell for $11,950. It carries an introductory five-year, 5,000-hour warranty. For more information, visit the Web site ( www.bendixking.com). — MPC
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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