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SpeedBird

A turbine-powered 1948 Luscombe is the new mascot of the Don Luscombe Aviation History Foundation

Story by Ron Kilber
Photography by Bob Shane
   More pictures coming soon!


When the Nike Company needed more publicity, all it did was wave a big sum of money around and sign Michael Jordan; the world beat a path to its door. But if you're not a Fortune-500 company, there's a way to gain attention that's just as good but much cheaper -- simply build a 150-hp gas-turbine-powered Luscombe and fly it to airshows around the country. True aviation enthusiasts would prefer to see this unique bird perform rather than Jordan any day. Sorry Michael.

Turbine Takeoff
It's a beautiful March Sunday morning here at the Chandler Municipal Airport in Arizona. The skies are clear, and visibility is unlimited. I'm with Doug Combs in the right seat of the Don Luscombe Aviation History Foundation's turbine-powered Luscombe. We're holding short of Runway 22R, waiting our turn for departure as soon as traffic on final lands.

I curiously ask Combs, "If the prop can go into Beta range, shouldn't we be able to back up?" Combs doesn't answer my question. Instead, he flicks the prop switch until the pitch indicator reads "Beta 17" (17 degrees negative), and a second or two later, we begin a gentle backward roll.

Naturally, my ear-to-ear grin says it all, and without saying a word, Combs knows this is the first time I've ever been in any airplane moving backwards under its own power. Sometimes words are just not that important.

My most obvious observations right now are the total lack of any vibration and the absence of noise associated with the exhaust of a piston engine. Also strange is the fact that we're ready for takeoff without having had to perform an engine runup. There's neither a magneto nor a carburetor, so what's left to check on a turbine engine?

We're cleared for immediate takeoff. Combs flicks the toggle switch mounted on the control stick, and as soon as the propeller pitch increases, we begin rolling into position. Simultaneously, he moves the turbine power lever from low-idle to high-idle position (the only settings available), and within a few seconds, we develop 150 hp and accelerate to rotation speed (60 mph).

A Piston Pilot's Expectations
I've been a piston-powered airplane pilot ever since I began my flight training more than 30 years ago. Even though this is my first experience with any turbine, understanding the concept and engine controls is not all that complicated. In fact, once mastered, they're easy to understand. You just have to remember that, when airborne, the turbine engine runs full rpm all the time (66,600 rpm, in this case). Control of what you want the powerplant to do is accomplished by adjusting the propeller pitch, which, in turn, varies the engine load, fuel consumption and exhaust gas temperature (EGT).

After we're airborne, our airspeed indicator reads 77 mph, and we attain a climb rate of 1500 fpm. Not at all bad for a power loading of 11.3 pph. We have about as much power as a new 160-hp Cessna 172, but our gross weight is 757 pounds less.

At 2500 feet AGL, leveling off produces a cruise speed of 145 mph in 50-degree F outside air. The propeller indicator displays 30 degrees of pitch, the engine tachometer reads 108 percent (66,600 rpm; 150 hp) and the EGT indicator shows 600 degrees C. That's 1,272 degrees F, and it's why they refer to the combustion chamber as the hot section.

I'm expecting much less noise in the cockpit. However, what this Luscombe makes up for with the amazingly smooth and quiet engine we loose to the added aerodynamic noise resulting from much greater airspeed. In fact, the decibels are more than I experienced flying an identical airplane equipped with an 85-hp Continental. Even so, I don't think there's a pilot alive who wouldn't trade a little more noise for a little more airspeed.

When I take the controls and enter a climb, I'm confused. Applying right rudder not only doesn't offset the P-factor force, it produces severe uncoordinated flight. It's actually left rudder that's needed. That's because the three-bladed prop is turning in the opposite direction than I'm expecting.

The controls are light and sensitive, and the airplane is very nimble and responsive -- especially when banking, due to the short wing span, which is fully twelve feet less than any standard Luscombe. Six feet of wing root on either side was removed to emulate the Monocoupe 110 Special, a successful racer of its time. The short wings not only bring the ailerons closer to the fuselage, they also reduce adverse yaw associated with control surfaces farther out. Plus, there's no extra weight to throw around way out there on the end of a long lever arm.

The idea for this turbine-powered airplane goes back to the 1950s, when Luscombe Aircraft Corporation wanted to provide a high-performance military trainer by boosting horsepower without adding weight. The Luscombe 8 series, already strong enough for more than 150 horses, only needed a more powerful engine to fit the military bill. And without any major redesign effort, it could be done quickly and inexpensively. So the engineers turned to the Boeing Airplane Company, which had already conceived a new lightweight turbine engine. For many reasons, however, the idea never got off the drawing board -- until, that is, Combs entered the picture more than forty years later.

Some Turbine Basics
Turbines have many advantages over their piston-engine counterparts. For one, they're light and very compact. This one is smaller than a lawn mower engine and weighs only 86 pounds -- 179 pounds less than a comparable 150-hp Lycoming. Piston engines have five times as many moving parts, and power adjustments require constant rpm changes. In contrast, the turbine has only simple rotation, and it operates with continuous combustion at full rpm.

Short of mechanical failure, the only real threat toward flame-out (engine failure) is fuel starvation. That's unlikely, even if the fuel pump fails. Gravity can provide sufficient fuel feed to keep the turbine engine running. So unless one goes inverted, runs out of fuel or accidentally catches a pant leg on the fuel cut-off value, there's no need to worry about the engine re-light procedure.

There can be other causes of engine failure. Mistakes can lead to a flameout, which not only occurs from fuel starvation, but can result when more fuel enters the turbine hot section than can be burned. It's like adding more charcoal lighter, but the fire snuffs out instead. Overloading the engine (sustained, excessive prop-pitch, which in turn demands more than rated power) can lead to engine failure (flame-out or mechanical failure).

Turbine-engine pilots must be aware that failure to adhere to EGT and engine parameters, which are temperature and altitude dependent, may result in engine failure, in which case, there are only two courses of action: re-light the engine or face a dead-stick landing.

Inasmuch as it's possible to harm a turbine engine by demanding more than rated power, suspicion of damage should result in an inspection of the hot section.

The EGT is a vital measurement of temperature- and altitude-dependent engine condition and performance. There are upper and lower temperature limits, which must never be exceeded. As with limits on any normally aspirated engine, failure to adhere to specified ranges can result in damage and expensive repairs.

The SpeedBird has redundant electrical systems for two reasons. When the starter is engaged, the battery voltage usually drops to 9 volts or so. This means remaining systems that require 12 volts can no longer perform optimally. Also, inasmuch as the propeller is actuated electrically, it's important to have backup power. For example, if there is total electrical system failure while flying, the turbine will blindly purr on, but the prop pitch can no longer be adjusted. Remember, without any alternative way to control engine power except with the pitch toggle switch, there's no way to reduce power and land without cutting the fuel, i.e., inducing flame-out of the engine. Before cutting the fuel, it's best to be able to reach the runway first.

Back to the Flight
After playing around for an hour or so, including a full stop at the Casa Grande airport, we decide to dead head back to Chandler. As we approach the airport and slow down, the aerodynamic sounds diminish substantially. In fact, now that we are cruising along as fast as any 85-hp Luscombe, the cockpit decibels are substantially less. Combs and I can easily converse without the intercom, whereas it'd be otherwise cumbersome and irritating in any normally aspirated Luscombe. A vacuum cleaner makes more noise than we experience now.

On our downwind leg, Combs brings the prop back to 20 degrees and then to 17 on final. Fuel flow falls to 10 gph automatically in response to less propeller load on the engine. We touchdown at 80 mph, and Combs commands the prop pitch to swing through 9 degrees and towards zero. When it finally enters Beta range, I hear the signature reverse-thrust sound as the tail drops. Our forward speed bleeds off quickly, and we're able to make the first turn-off without using wheel breaks.

Afterwards
Starting the engine before flight was remarkably simple. Basically, the starter was activated until the turbine RPMs reached 18 percent (15% is minimum for ignition). Then the fuel was turned on, and when the characteristic ignition sound was heard (similar to lighting a charcoal grill) -- WHOOSH -- we were in business. Of course, the prop must be in neutral-pitch position (Beta 3 to plus 3), otherwise, flight might occur right from the ramp, or worse, personal injury and property damage may result. Not only that, insufficient intake airflow while stationary on the ramp can overtemp the engine.

Design and construction began in 1995. My first question to Combs when he introduced me to the SpeedBird: "Why not just use a 150-HP engine; wouldn't it be much cheaper?"

To my great surprise, Combs said the turbine engine actually costs about the same as a brand new Lycoming. In fact, he told me the project started out that way but changed course when the turbine engine was discovered. Sure, the engine mount, propeller, electrical system and the cowling required some redesign and modifications -- not to mention the addition of a reduction gearbox -- but how else can you have fun in life? Besides, there already are plenty of 150-hp normally aspirated Luscombes in the world.

The Luscombe airframe, one of the toughest ever built, is already approved for 150-hp Lycoming installations. Anyone would think the longer nose might require a major redesign of the airframe to keep it from being front-heavy. But the longer moment arm of the 86-pound turbine, it turned out, was about equal to the heavier 85-hp, 225-pound Continental with a shorter moment arm. As luck would have it, things worked out just right.


Luscombe Aircraft Corporation

The golden age of aviation began with Lindbergh's May 1927 Spirit of St. Louis solo flight from New York to Paris. Thereafter, aviation experienced a glorious time period in which airplane pioneer Don Luscombe conceived the closed-cabin Monocoupe -- a low-cost, fabric-covered monoplane. He also experimented with an all-metal design, the Luscombe Phantom. Great strides were being made in aviation history, and only a mere 24 years earlier, about the time Lindbergh was born, did Orville and Wilbur Wright make civilization history flying their Flyer.

In 1933, about a year after Amelia Earhart became the first woman to fly the Atlantic solo, Don Luscombe and an associate left Monocoupe of Moline, Illinois, to form their own company in Kansas building airplanes using sheet-metal skin as a structural member. The design proved extraordinarily strong and construction efficient, and by the time Amelia Earhart and Fred Noonan set out on their doomed around-the-world attempt, the Luscombe was evolving into a series of airplanes known as the Luscombe 8 series (8 and 8A through 8F) and Silvaires. Horsepower increased from the 65-hp, 100-mph 8A model to the 75- 85- and 90-hp versions.

These little airplanes were very popular and in high demand and eventually forced competitors to take note and rethink their strategies. Cessna was first with its 120 model, and eventually Beechcraft and Piper followed suit with an all-metal design of their own. Ever since, Luscombe has been credited with moving general aviation away from tube-and-rag fabrication.

Luscombe production continued through 1961, first in West Trenton, New Jersey, then Dallas, Texas, and finally Fort Collins, Colorado. Then, hard economic times and business difficulties forced a shut-down. Thereafter, the type certificate and drawings went into storage and hiding, and much of the aircraft tooling and jigs were lost or destroyed. Factory restoration and technical support were tough to obtain at any price, and Luscombe owners and mechanics were at wits' end through difficult repairs with nonexistent technical support. That is, until the Luscombe Foundation came along in 1992, some 30 years later, preserving forever that important time in aviation history, before flying got too complex and expensive for individuals alone and before it passed into the hands of government and industry.

Today, more than 3,000 of the originally produced 6,000 Luscombe airplanes are still flying. Most of these -- about 2,400 -- are registered in the United States. With the continued support of the Don Luscombe Aviation History Foundation (DLAHF), it's certain these strong and beautiful little airplanes will be around for a very long time.

For anyone desiring a brand new Luscombe, Renaissance Aircraft, LLC of Monkton, Maryland intends to begin production of the 150-hp Lycoming version under license from the DLAHF. Preliminary sales data claims a cruise speed of 140 mph, 2000 fpm climb rate, and a base price of $67,900.


SpeedBird's Owner

The Don Luscombe Aviation History Foundation, also known as the Luscombe Foundation, is a non-profit aviation historical preservation and educational group charged with preservation of the historically valuable aviation assets of the late Luscombe Aircraft Corporation.

DLAHF is the brainchild of Doug Combs, an America West Airlines 737 Captain, whose aviation career began at the University of Illinois where he not only earned his private and commercial wings, but his A&P license, too. It's also where he obtained and restored his first airplane, a vintage Luscombe, which he still tinkers and plays with today. Combs has been with America West for thirteen years, prior to which he gained valuable experience flying Part-135 BE-18s in Detroit and Chicago. After moving on to corporate flying in other regions of the Midwest, he eventually became a 707 captain for the non-defunct Denver-based Ports Of Call. Combs lives in Gilbert, Arizona, with his wife and one child, with another on the way.

A team of Luscombe volunteers began forming the DLAHF in 1989, with the primary goal of procuring and preserving the Luscombe aircraft type certificate and engineering data. The initial Board of Directors included Combs, Don and Donna Warner, Laurie Eder, Ron Price and Jim Zazas. They finally accomplished their goal in 1992, using donations and foundation subscriber support. These assets are now held to benefit Luscombe enthusiasts and owners who fly and rebuild airplanes.

The Luscombe Foundation operates as a manufacturer, coordinating with the FAA for improvements and upgrades of the Luscombe design, as well as serving as a technical-support resource. The Luscombe Foundation is often credited by owners and enthusiasts as being the savior of the design, inasmuch as the prior owner had intentions to destroy all original type certificate 694 documents in an effort to create a tax loss and reduce his legal liability for those airplanes still flying.

Funding for the Luscombe Foundation comes not only from manufacture of new production parts, but also from an annual raffle. The winner receives a fully restored Luscombe Silvaire. Data packages are also made available for sale, as well as an occasional completely restored airframe. The foundation has received generous in-kind donations from several private benefactors and corporate sponsors. The AOPA and EAA have been supportive of the Luscombe Foundation's preservation efforts.

The Luscombe Foundation offers intern employment to students and graduates of A&P schools, as well as introductory aviation experience to teens through the EAA's Young Eagles program. The foundation holds maintenance and historical seminars at each of the major U.S. airshows annually.

DLAHF's new goal is to build a museum facility and new home at the Chandler Municipal Airport. Public support is crucial for continued production progress and educational campaigns. For more information, contact the Don Luscombe Aviation History Foundation, Dept. PPM, Box 63581, Phoenix, AZ 85082; 602/917-0969, fax 602/917-4719; silvaire@luscombe.org, or via the Web: http://www.luscombe.org


SpeedBird NX2638K

SPECIFICATIONS
Wingspan................23 ft., 5 in.
Wing area................110 sq. ft.
Length......................22 ft., 7 in.
Height...............................75 in.
Tire track..........................75 in.

Weights and Loading
Empty weight..................860 lb.
Gross weight................1700 lb.
Wing loading.......15.4 lb./sq. ft.
Power loading.......11.29 lb./hp

Engine
150 hp APEX T62-32

Propeller
NSI CAP140

PERFORMANCE
Maximum design speed..........192 mph
Rate of climb...........................2500 fpm
........(59 deg. F, 1400-lb. gross weight)
Cruise at 14,000 msl...............160 mph
.................................175 mph maximum
Best rate of climb......................77 mph
Operational ceiling..................17,999 ft.
......................(DME required for higher)
Landing speed...........................80 mph
Stall speed.................................55 mph
Cruise fuel consumption......14-18 gph;
.........................................max 22.5 gph
Fuel capacity..................16.2 gal./wing;
....................................21 gal. aux. tank
Range................................3 hr., 15 min.


Addendum:

At presstime, PRIVATE PILOT learned the cause of Doug Combs' dead-stick mishap near Cut'n Shoot, Texas while returning to Arizona from Florida's 1999 Sun'n Fun. A caterpillar or other larvae-producing insect took up residence in the Luscombe's fuel vent. The plug was sufficient to resist the boost pump pickup capacity, which resulted in a lack of fuel flow and an engine flame-out -- not to mention a crash landing. Miraculously, Combs survived and actually was able to use his cell phone to call his wife while the ambulance and police were en route. Unfortunately, he did break the C2 vertebrae in his neck, and the airplane had to be trucked back to Chandler. A full recovery is expected not only for Combs but the turbine-powered Luscombe, too.


Copyright © 1999 Ron Kilber All rights reserved.

Ron Kilber, a private pilot since 1967, lives in Tempe, Arizona
Email: rpknet@aztec.asu.edu

Bob Shane is an aviation photographer who lives in Phoenix, Arizona
Email: bobshane@usa.net