AOPA Pilot Magazine
May 2001 Volume 44 / Number 5
AOPA's 2001 Bonanza Sweepstakes: Up, Up, and Away
Turbonormalizing improves an airplane's utility
You can take this one to the bank — installing a turbonormalizer will improve an airplane's utility. This was demonstrated following the installation of a Tornado Alley Turbo (TAT) Whirlwind II turbonormalizer system on the Superior Air Parts Certified Millennium engine in the AOPA Sweepstakes Bonanza.
Turbonormalizing the sweepstakes Bonanza had the same effect on our 1966 Beech V35 Bonanza that Viagra apparently has had on Bob Dole — the sweepstakes Bonanza can now keep up with airplanes half its age. Before we describe what was done, let's talk about why it was done.
Turbonormalizing will allow the winner of the sweepstakes Bonanza to more fully utilize the airplane. Even at 35 years old, the standard V35 Bonanza is very capable. An airplane with a service ceiling above 16,000 feet, cruise speeds above 165 KTAS, and a still-air range of more than 750 nm (on 74 gallons) is certainly very useful, but the installation of a turbonormalizer transforms this good airplane into a great — indeed, a twenty-first century — airplane.
A turbonormalizing system collects engine exhaust gases that are normally pumped overboard. These gases are used to indirectly drive an air compressor. This compressed air artificially creates sea-level atmospheric air pressures when it is pumped into the engine. In this way the engine can develop full power (300 horsepower) at altitudes up to and above 20,000 feet msl.
The building blocks
A turbocharger consists of an exhaust gas-driven turbine wheel in a cast-iron scroll housing and a compressor wheel in an aluminum scroll housing, with both wheels mounted on a common rotating shaft. The housings, the shaft, and the two wheels make up the turbocharger assembly. The center shaft is supported in a bushing that is constantly lubricated by circulating engine oil. The turbocharger is a component of the turbonormalizer system.
The Tornado Alley Turbo Whirlwind II system replaces the original exhaust system with a heavy-duty stainless steel system. Exhaust gases are collected from the engine cylinders and are routed to the turbine wheel inlet.
At low altitudes, where the air is denser, the compressor doesn't have to compress a lot of air to maintain the manifold pressures necessary for the engine to produce 65-percent to 75-percent power. As the airplane climbs, the air pressure decreases, so the compressor must deliver more air. A turbonormalizer system increases the amount of compressed air that is delivered to the engine by controlling how much of the total exhaust gas bypasses the turbocharger. This bypass route is controlled by a butterfly valve called a wastegate. Closing the wastegate increases the amount of exhaust gases being forced past the turbine wheel. The resultant higher rpm of the turbine and compressor wheels increases the amount of compressed air delivered to the engine.
In this system the position of the wastegate is controlled by the absolute pressure controller. This controller monitors the pressure from the compressor output and maintains a constant air pressure in the "upper deck" of the system by adjusting the position of the wastegate.
The upper deck is the part of the turbonormalizer system that is located between the compressor outlet and the engine throttle plate. The controller is designed to maintain the upper deck pressure at two to three inches of pressure above the maximum manifold pressure the engine would ever need. This type of system works the turbocharger a little harder than some "on-demand" systems, since the components of this system are adjusted to always maintain 33 to 34 inches of upper deck pressure, but this is offset by the fact that there's never any turbocharger lag or spool-up time. A pressure relief valve (pop-off valve) is mounted in the ducting between the compressor outlet and the engine, and is designed to open if the controller malfunctions and allows upper deck pressure (and consequently manifold pressure) to increase beyond safe limits.
The system operation is simple. The pilot adjusts the throttle to select the manifold pressure he wants, and the system automatically maintains a constant upper deck pressure, which maintains a constant manifold pressure.
Compressing air raises its temperature. Since we would like the air to be sea-level dense, and as near standard temperatures as possible, sophisticated turbonormalizing systems have an air-to-air radiator in which the heated, compressed air from the compressor is cooled by ram air before it enters the engine. This device is called an intercooler, and the Tornado Alley Turbo system has a very efficient one mounted below the engine on the right side.
After the initial acquisition costs of a turbonormalizing system, are there any other costs involved? Yes, there will be slightly higher costs associated with a turbonormalizer system, especially during an engine overhaul, when the turbo components (including the exhaust system) should also be overhauled. The Tornado Alley system is designed for long life, uses proven components, and shouldn't have any trouble matching engine TBO numbers before needing overhaul.
Some new powerplant management techniques (we will get to Tornado Alley's method in a moment) will have to be adhered to, and the pilot will have to learn about hypoxia, the use of oxygen, and high-altitude operations. Is the engine overworked or stressed because of the installation of a turbonormalizer? The potential exists to abuse a turbonormalized engine, primarily if the pilot always insists on going as fast as possible. As pilots get used to the system, they will learn that a turbonormalized airplane can easily climb above the thick, draggy air of lower altitudes to where even conservative power settings yield impressive speed gains. TAT likes to tout the advantages gained from its system at lower altitudes. True airspeeds are increased, and safety margins rise as power-robbing conditions such as high ambient temperatures or high airport elevations are simply no longer a problem.
Before Tornado Alley Turbo
In 1994, AOPA Pilot reported on flying George Braly's turbonormalizer-equipped 1967 V35 from Orlando, Florida, to Ada, Oklahoma (see "Higher Flyer," March 1994 Pilot). Braly started Tornado Alley Turbo Inc. after acquiring the turbonormalizing STCs for the Beech Bonanza and the Cessna 185 from FliteCraft Turbo, of Pagosa Springs, Colorado. Before Tornado Alley upgraded the original FliteCraft installation, cylinder head temperatures (CHTs) in Braly's Bonanza often exceeded 400 degrees Fahrenheit during climbs to altitude. Low-altitude performance also suffered when ambient temperatures were high.
Braly, an engineer by training, cooled the installation down with the Whirlwind II upgrades. Changes include a new composite airbox and alternate air door relocation, a cooling kit for the number-2 and number-6 cylinders (this mod cools these two cylinders by 30 to 35 degrees), cowl louvers adapted from current A36 Bonanzas, and a set of baffle louvers to enhance cooling airflow past the cylinders.
The original intercooler has been replaced with a more effective "Rammer" unit that, combined with changes in the under-cowl plumbing and clever tricks such as recessing the landing light for more airflow, has effectively doubled the volume of air passing through the intercooler. The result is improved hot-weather takeoff performance, cooler CHTs, and safer detonation margins. All of the Whirlwind II upgrades can be retrofitted to earlier installations.
The TAT method of powerplant management
The Whirlwind II upgrades include a set of turbo GAMIjectors (Braly is also the chief engineer at GAMI). GAMIjectors are flow-matched fuel-injection nozzles that equalize the power output among all cylinders. Tornado Alley believes that long engine life is directly related to lowering engine temperatures. As a result, each new owner of a Tornado Alley system undergoes training in how to fly the TAT way.
The TAT method of setting power for climb involves setting the throttle wide open, reducing the prop rpm to 2,500 after the airplane is cleaned up for climb, and then using the mixture control to adjust the turbine inlet temperature (TIT) to a target temperature. The target TITs are 1,280 to 1,300 degrees from sea level to 10,000 feet; 1,260 to 1,280 degrees from 10,001 to 17,000 feet; and 1,240 to 1,260 degrees (with engine rpm increased to 2,600 rpm) when climbing above 17,001 feet. If the TAT procedure is followed, climb speed targets are 115 to 120 KIAS up to 10,000 feet, 115 KIAS up to 17,000 feet, and 105 to 110 KIAS above 17,000 feet.
Because the system's automatic wastegate controls the engine manifold pressure, and the prop governor controls the engine rpm, the pilot's workload is reduced to flying the airplane — and adjusting the mixture as necessary to maintain the target temperatures.
If any CHT goes above 380 degrees during the climb, the mixture is adjusted as necessary to bring the CHT back down to 380.
The TAT cruise
Cruise engine management consists of running the mixture lean of peak (LOP). This is accomplished after leveling out, closing the cowl flaps, and accelerating by performing the big pull. The big pull consists of grabbing the mixture knob and smoothly pulling it back until the fuel flow needle is indicating approximately 15 gallons per hour on the lean side of peak. After a short period of time, the mixture is slowly richened until peak EGT is found, and then leaned again until the turbine inlet temperature is approximately 80 degrees F lean of peak.
Up until GAMI came on the scene with its finely tuned fuel-injection nozzles that made lean-of-peak operations practical, the most accepted practice was to run one of these engines with the mixtures set somewhere between 100 to 50 degrees rich of peak to keep temperatures down. According to extensive testing by Tornado Alley, its method keeps TIT, EGT, and CHT temperatures even lower than rich-of-peak methods, and TAT believes cool temperatures are the key to long engine life. In spite of a great deal of solid evidence to support GAMI's methods, not everyone is convinced. Sometimes this is because of a reluctance to let go of old ideas, and sometimes it's because opponents don't realize how thoroughly GAMI and TAT test their ideas.
The Carl Goulet Memorial Test Cell
Braly and his staff in Ada, Oklahoma, have built one of the most sophisticated airplane engine test cells on the planet. Rather than guessing what goes on inside the combustion chamber, they devised a way to sample the combustion chamber pressures and display a smorgasbord of data from their test-cell engines. What have they learned? That lean-of-peak operations, if correctly performed by the pilot, are safe, result in lower temperatures than rich-of-peak operations, and do not result in destructive detonation.
These facts are borne out by years of test-stand study. For a look at TAT's plans for the future — and you can bet they're not resting on their laurels — go to the Web site (www.taturbo.com). If you want to take a look at some of the data being gathered, go directly to the test-stand Web site (www.engineteststand.com).
Turbonormalizing expands an airplane's operating envelope. Because ample power is always available, climbing up out of icing temperatures becomes possible. When selecting a cruise altitude there's a whole band of airspace between approximately 10,000 and 17,500 feet where traffic is generally light, because it's too high for normally aspirated airplanes and too low for turbine-powered airplanes. One result is that direct IFR flight plans are often approved. Again, this translates into a more efficient way to fly.
The turbonormalizer, because it can easily provide sea-level manifold pressures up to flight-level altitudes, allows the pilot to pick up some "free" airspeed by climbing up to altitudes where the atmospheric drag is reduced. The combination of less drag and robust power results in higher true airspeeds, and only slightly higher fuel-consumption numbers. During the first testing and adjustment flights of the sweepstakes Bonanza, true airspeeds of 215 knots at 17,500 feet were observed with a fuel burn of 18.5 gallons per hour. The hottest cylinder head temperature was 358 degrees F during the 215-KTAS flight.
The TAT method of climb and cruise operation is designed to keep cylinder head temperatures below 380 degrees F. This is a full 80 degrees below the manufacturer's redline. These methods have been thoroughly tested, and are in keeping with the goal of the AOPA Bonanza Sweepstakes project. Once we realized all the benefits and weighed them against any liabilities, the installation of the Tornado Alley turbonormalizer system was a no-brainer. It's a new century, and this system transformed a 35-year-old airplane into a twenty-first century speed demon.
E-mail the author at email@example.com.
AOPA would like to thank the following companies that are donating or discounting their products and services to refurbish AOPA's 2001 Bonanza Sweepstakes project or are otherwise assisting with the project.
Engine compartment paint
Ada Aircraft Painting LLC, 2800 Airport Rd, Hangar D, Ada, Oklahoma 74820; telephone 580/332-6086; fax 580/332-4547; e-mail firstname.lastname@example.org.
Fuel cells (bladders)
Aero-Tech Services, Inc., 8354 Secura Way, Santa Fe Springs, California 90670; telephone 562/696-1128; fax 562/945-1328.
Inertia reels, seat belts, and shoulder harnesses
Aircraft Belts, Inc., 200 Anders Lane, Kemah, Texas 77565; telephone 281/334-3004; fax 281/538-2225; www.aircraftbelts.com.
Medeco door locks
Aircraft Security and Alert, 3863 Royal Lane, Dallas, Texas 75229; telephone 214/956-9563; fax 214/956-9960; www.aircraftsecurityalert.com.
Air Mod, 2025 Sporty's Drive, Clermont County Airport, Batavia, Ohio 45103; telephone 513/732-6688; www.airmod.com.
Alpha Coatings, Inc., 310 West 12th St., Washington, Missouri 63090; telephone 800 875-3903; fax 636 390-3906; www.alphacoatings.com.
Technical guidance and one-year free membership for winner
American Bonanza Society, P.O. Box 12888, Wichita, Kansas 67277; telephone 316/945-1700; fax 316/945-1710; www.bonanza.org.
AM/FM radio with CD player
Avionics Innovations, Inc., 2450 Montecito Rd., Ramona, California 92065; telephone 760/788 2602; fax 760/789 7098; www.avionicsinnovations.com.
Ayers, Inc., 2006 Palomar Airport Road, Carlsbad, California 92008; telephone 760/431-7600; fax 760/431-2848.
Standby alternator system
B&C Specialty Products, Inc., 123 East 4th, Newton, Kansas 67114; telephone 316/283-8000; www.bandcspecialty.com.
Sloped windshield, windows, vortex generators, aileron and flap gap seals
Beryl D'Shannon Aviation Specialties, Inc., P.O. Box 27966, Golden Valley, Minnesota 55427; telephone 800/328-4629 or 763/535-0505; fax 763/535-3759; www.beryldshannon.com.
Proficiency course for winner and spouse
Bonanza/Baron Pilot Proficiency Program, Inc., Mid-Continent Airport, P.O. Box 12888, Wichita, Kansas 67277; telephone 970/377-1877; fax 970/377-1512; e-mail email@example.com; www.bppp.org.
Prepurchase inspection assistance
Coastal Valley Aviation, Inc., 3119 Liberator St., Santa Maria, California 93455; telephone 805/928-7701; fax 805/928-4427; www.coastalvalleyaviation.com.
Concorde Battery Corporation, 2009 San Bernardino Road, West Covina, California 91792; telephone 626-813-1234; fax 626-813-1235; www.concordebattery.com.
Dual control yoke and control wheels
Cygnet Aerospace Corporation, , P.O. Box 6603, Los Osos, California 93412; telephone 805/528-2376; fax 805/528 2377; www.cygnet-aero.com.
Engine oil analysis kits
Engine Oil Analysis, 7820 South 70th East Avenue, Tulsa, Oklahoma 74133; telephone/fax 918/492-5844; e-mail firstname.lastname@example.org.
ExxonMobil Aviation Lubricants, 7400 Beaufont Springs Drive, Suite 410, Richmond, Virginia 23225; telephone 804-743-5762; fax: 804-743-5784; www.exxon.com/exxon_lubes/aviation_fr.html.
Avionics suite (including audio panel / marker beacon / intercom, transponder, and dual nav / com / GPS units)
Garmin International, 1200 East 151st St., Olathe, Kansas 66062; telephone 913/397-8200; fax 913/397-8282; www.garmin.com.
Precision matched fuel injection nozzles
General Aviation Modifications, Inc., 2800 Airport Rd., Hangar A, Ada, Oklahoma 74820; telephone 888-FLY-GAMI, 580/436-4833; fax 580/436-6622; www.gami.com.
Tires and tubes
Goodyear Tire and Rubber Company, 1144 E. Market Street, Akron, Ohio 44316; telephone 330/796-6323; fax 330/796-6535; www.goodyear.com.
Avionics and instrument panel installation
J. A. Air Center, DuPage Airport, 3N060 Powis Rd., West Chicago, Illinois 60185; telephone 800/323-5966 or 630/584-3200; fax 630/584-7883; www.jaair.com.
Wing tip fuel tank system
J. L. Osborne, Inc.,, 18173 Osborne Rd., Victorville, California 92392; telephone 800/963 8477, 760/245 8477; fax 760/245 5735; www.jlosborne.com.
J.P. Instruments Inc., 3185-B Airway Ave., Costa Mesa, California 92626; telephone 800/345-4574, 714/557-3805; fax 714/557-9840; www.jpinstruments.com.
Beryl D'Shannon upgrade and modification installations
Therese and Doug Kelly, Rt 2, Box R45, Military Highway, Mercedes, Texas; telephone 888/787-0689.
McCauley Propeller Systems, 3535 McCauley Drive, Vandalia, Ohio 45377; telephone 800/621-PROP or 937/890-5246; fax 937/890-6001; www.mccauley.textron.com.
MAGIC EFIS display system
Meggitt Avionics, Inc., 10 Ammon Drive, Manchester, New Hampshire 03103; telephone 603/669-0940; fax 603/669-0931; www.meggittavi.com.
Four-place oxygen system with Electronic Delivery System (EDS)
Mountain High E & S Company, 625 S.E. Salmon Avenue, Redmond, Oregon 97756-8696; telephone 800/468-8185, 541/923-4100; fax 541/923-4141; www.mhoxygen.com.
Murmer Aircraft Services, Houston SW Airport, 503 McKeever Rd. #1504, Arcola, Texas 77583; telephone 281/431 3030; fax 281/431 3031; www.murmerair.com.
Rebuilt seat back assist cylinders
G. Nichols & Co., 1923 Jackson Street, St. Clair, Michigan 48079; telephone 810/329-7083.
Audio landing gear and overspeed (Vne) warning system
P2, Inc., P.O. Box 26, Mound, Minnesota 55364-0026; telephone 888/921-8359, 952/472-2577; fax 952/472-7071; www.p2inc.com.
Landing gear retraction boot set
Performance Aero, East Kansas City Airport, Hangar L-1, Grain Valley, Missouri 64029; telephone 800/200-3141 or 816/847-5588; fax 816/847-5599; www.bonanza.org/performance/.
San Diego Aircraft Sales, Gillespie Field, 1987 N. Marshall Ave., Ste. 110, El Cajon, California 92020; telephone 619/562-0990; fax 619/562-0121; www.sandiegoac.com.
Scheme Designers, 277 Tom Hunter Road, Fort Lee, New Jersey 07024, 201-947-5889; www.schemedesigners.com.
SIRS Product Services, 25422 Trabuco Rd. #105, PMB 436, Lake Forest, California 92630 telephone 310/325-3422; fax 949/951-0778; www.sirsproducts.com.
Cabin sound suppression kit
Skandia Inc., 5002 North Highway 251, Davis Junction, Illinois 61020; telephone 815/393-4600; fax 815/393-4814; www.skandia-inc.com.
Camloc cowling fasteners
Skybolt Aerospace Fasteners, 9000 Airport Road, Leesburg Municipal Airport, Leesburg, Florida 34788; telephone 352/326-0001; fax 352/326-0011; www.skybolt.com.
Autopilot and EFIS certification
S-Tec Corporation, One S-Tec Way, Municipal Airport, Mineral Wells, Texas 76067; telephone 940/325-9406; fax 940/325-3904; www.s-tec.com.
Superior Air Parts, Inc., 14280 Gillis Rd, Dallas, Texas 75244; telephone 972/233-4433; fax 972/233-8809; www.superiorairparts.com.
Airframe anti-ice system
TKS Ice Protection Systems, 3213 Arnold Ave., Salina, Kansas 67401; telephone 888/865-5511 or 785/493-0946; fax 785/493-0959; www.weepingwings.com.
Turbonormalizer system and annual inspection
Tornado Alley Turbo, Inc., 300 Airport Rd, Ada, Oklahoma 74820; telephone 877/359-8284 or 580/332-3510; fax 580/332-4577; www.taturbo.com.
Engine buildup and test
Western Skyways, Inc., 1865 Launa Dr., Montrose, Colorado 81401; telephone 800/575-9929 or 970/249-0232; fax 970/249-4155; www.westernskyways.com.
Whelen Engineering Co., Route 145, Winthrop Road, Chester, Connecticut 06412-0684; telephone 860/526-9504; fax 860/526-4078; www.whelen.com.