February 1, 2002
JULIE K. BOATMAN
The Piper Cherokee 140 matches a moderately powered engine to a forgiving wing for stable and predictable performance. But there are times when a mountain ridge looms ahead, or the trees at the end of the runway look taller than usual, that the pilot of a 140 may want a little more guts than the 140- to 160-horsepower engine up front normally allows. Power Flow's tuned exhaust for the 140 packs that extra power.
We flew a 1969 Cherokee 140 with a 150-hp Lycoming O-320 before and after the installation of the Power Flow system. Darren Tilman, general manager of Power Flow, served as demo pilot, engineer, and maintenance technician on the upgrade, which took place on the AOPA ramp — a testimony to the ease of the work involved. The system takes eight to 10 hours to install and replaces the stock exhaust headers, collector, and muffler with new corrosion-resistant stainless-steel parts. By scavenging the cylinder's exhaust pulse with the suction created by the previous pulse, the tuned exhaust fosters the smooth flow of exhaust gas and reduces the pressure in the muffler system that can cause the exhaust from one cylinder to back up into another cylinder. Thus, the cycle runs more efficiently and fuel burn decreases.
Prior tests of the Power Flow system on a Cessna 172 (see " Pilot Products," March 2000 Pilot) showed performance increases consistent with the company's claims. Though testing conditions made it difficult to compare precisely the stock airplane with the modified version, the 140 also posted measurable improvement with the new exhaust system. The 140 we tested had an Alcor multi-point CHT/EGT system and a DMA fuel flow computer, so engine temperatures and fuel flows were accurately measured. An electronic tach sensor allowed us to precisely record rpm.
The morning we tested the stock 140, updrafts and the turbulence created by a stiff west wind influenced the airplane's performance, especially during the climb tests. However, increases in rpm were easy to quantify and were consistently higher across the board. Our first evidence came during the takeoff roll: The stock airplane took 15.5 seconds to accelerate to 60 mph at 2,300 rpm, while the revised 140 took a full second less at 2,345 rpm, translating into 100 feet of runway saved.
During the climb test, the modified 140 essentially matched or beat the stock 140 on updrafts. Overall, we saw a rate of climb that averaged 509 fpm with the stock exhaust grow about 8 percent to 546 fpm with the new system. After leaning, the Power Flow system averaged 500 fpm from 5,000 to 7,500 feet, a gain of 46 percent over the previous day's numbers.
The increased rpm tells the tale. Before leaning at 5,000 feet, the stock system averaged 2,431 rpm, while the Power Flow system averaged 2,479 rpm, a gain of 48 rpm in stabilized flight. After leaning, averages were 2,470 rpm and 2,487 rpm, for a gain of 17 rpm. Airspeed in cruise at 8,500 feet indicated 118 mph, up from 110 mph.
One benefit to the Power Flow system is its ability to even out EGTs and slightly lower CHTs. Before the exchange was made, EGTs were widely different, with the number-three and number-two cylinders registering a variance of 100 degrees or more. The switch brought temps to within 25 degrees. CHTs remained similar to the previous trial, with the average showing 8 degrees cooler at 8,500 feet and leaned. Fuel flow at full throttle and 8,500 feet was 9.9 gph at 2,650 rpm; at 2,430 rpm and 6.9 gph the engine started to run rough. For an indicated airspeed of 108 mph at 5,500 feet, an rpm of 2,392 resulted in a fuel flow of 7.2 gph, 2 gph less than the engine with the stock exhaust running at a higher rpm and matched airspeed.
With increased power, one caveat to the system is that it may spike rpm past the redline. This didn't happen in our test airplane; owners may find they need to repitch their props after the installation.
Overall, the Power Flow tuned exhaust delivers what the company promises. Though each installation is different, Power Flow is proving that its numbers are honest. Next up for Power Flow? Other O-320/O-360 engine-equipped airplanes, such as the Grumman Tiger, Cheetah, and Traveler, and the Piper Cherokee 180 and Archer. Down the road, Tilman has set his sights on the Mooney M-series, and possibly the Beechcraft Bonanza. The Power Flow system for the 140 retails at $3,675. For more information, contact Power Flow Systems Inc., 1585 Aviation Center Parkway, Hangar 804, Daytona Beach, Florida 32114; telephone 877/693-7356 or 904/253-8833; fax 904/248-1587; or visit the Web site ( www.powerflowsystems.com). — JKB
Chris Smith, of AirSmith LLC, developed FlightPrompt for PDAs specifically for private pilots who rent aircraft. The software for the Palm operating system comes in monochrome and color versions to fit personal digital assistants (PDA). The goal was to pro.vide a standard routine for pilots to follow before and during flighj no matter what aircraft they fly — a handy tool if you often switch between a couple of different aircraft models. The checklists in FlightPrompt follow a protocol that allows you to determine what checklist items are required for all flights and which are optional on subsequent flights, such as preflight items. The interface can be used without the stylus because of large buttons on the display, and the menus are designed so that any checklist can be accessed quickly. FlightPrompt runs on any PDA that features a Palm 2.0 OS or higher. FlightPrompt retails for $30 and can be purchased online ( www.flightprompt.com) or www.palmgear.com). A free 14-day trial version is also available. For more information, contact AirSmith LLC; telephone 206/780-1312. — JKB
The second edition of Job Hunting for Pilots: Networking Your Way to a Flying Job by Gregory N. Brown, a columnist for AOPA Flight Training magazine, is available from Iowa State University Press for $21.95. The 208-page book aids the applicant in developing important contacts inside the industry. Included are pilot résumés, cover letters, and interview preparation tips. The book includes help for a wide range of applicants, from those just beginning their careers to military pilots transitioning to civilian flying jobs. For more information, contact Iowa State University Press, 2121 South State Avenue, Ames, Iowa 50014-8300; telephone 800/862-6657 or 515/292-0140; fax 515/292-3348; or visit the Web site ( www.isupress.com). — Alton K. Marsh
Avidyne Corporation announced its new large-screen EX5000 flight situation display (FSD). The FSD presents information in either horizontal or vertical formats and is expected to retail for $12,950. Avidyne also joined forces with Cirrus Design to bring the new EX5000C to the cockpits of SR20 and SR22 aircraft. The EX5000C brings in data from the Garmin GNS 430 GPS navigator and Goodrich's WX-500 Stormscope and Skywatch Traffic Awareness System to display on a 10.4-inch diagonal screen. The FSD will be installed in new SR20s and SR22s beginning in the first quarter of this year. Datalink is now available to Avidyne customers as well: The FlightMax DX50 provides weather information via the Orbcomm satellite network. Price for the DX50 and antenna is $2,950; an introductory price of $2,450 is offered for customers who purchase an Avidyne FSD by March. For more information, contact Avidyne, 55 Old Bedford Road, Lincoln, Massachusetts 01773; telephone 800/284-3963 or 781/402-7585; fax 781/402-7599; or visit the Web site ( www.avidyne.com). — JKB
Adding to The Educated Owner video series, Approach Aviation announced the release of Volume III: Introduction to Aircraft Ownership. This installment helps prospective owners analyze the costs of aircraft ownership and takes them through the selection, prepurchase inspection, and purchase transaction of an aircraft. It also includes detailed information on preventive maintenance and annual inspections, and offers other tips concerning aircraft ownership. Volume III retails for $39.95; the three-volume series is specially priced at $109.95. For more information, contact Approach Aviation, 24 Deer Path, Suite 6, Maynard, Massachusetts 01754; telephone or fax 978/461-2415; or visit the Web site ( www.approachaviation.com). — JKB
Pilots have been asking why GPS nav data updates can't be inexpensive and easy, and now they are. Jeppesen has announced the creation of a link on its Web site that allows owners of Garmin handheld GPS units to update navigation databases online for $35. Traditionally, these units are updated via floppy disks at a cost ranging from $90 to $130, so the changes reflect a large savings for the average customer — and an argument to fly with more current data in these handheld devices, which are used for VFR flight and are not required to adhere to the same update schedules that IFR-approved panel-mount devices are. For more information, visit Jeppesen's Web site ( www.jeppesen.com). — JKB
Stenbock and Everson Inc. announced an online flight planner, FlightPrep, featuring interactive control of flight plans. An active chart matrix allows pilots to manipulate a planned route through the use of rubber-banding or a route editor. Maps include terrain features in addition to geographical and navigational information in a unique, clean presentation. A direct link to DUATS online downloads weather into the flight planner. The company offers several subscription levels available on a month-to-month basis, ranging in price from $12.95 for a VFR version, to $16.95 for an IFR version with 100 editable aircraft, to $33.95 for corporate versions offering custom aircraft and service. For more information, visit the Web site ( www.flightprep.com). — JKB
Telex Communications Inc. has added a single-sided version of its Airman 750 headset to its product line. The headset features a miniature amplified noise-canceling microphone for noise reduction, and the single receiver includes a replaceable cushion and weighs 2.4 ounces, according to the manufacturer. The headset retails for $232. For more information, contact Telex Communications, 12000 Portland Avenue South, Burnsville, Minnesota 55337; telephone 877/863-4168 or 952/884-4051; fax 952/884-0043; or visit the Web site ( www.telex.com/aircraft). — JKB
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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