Tom Aberle's Phantom
By Pat Panzera, EAA 555743, email@example.com and John Moyle, EAA 4260
Tom Aberle’s Mong biplane Phantom at the 2004 Reno National Championship Air Races. Photo by Atsushi “Fred” Fujimori.
In most cases it takes a team effort to break new ground in any field, and air racing is no exception. The requirements of adequate funding, enlightened engineering, meticulous preparation, and skillful piloting must be brought together to form an alliance that can compete effectively, let alone win the National Championship. This story is about one such group, put together by Tom Aberle of Fallbrook, California.
Tom astride his desk in his office/hangar in Fallbrook, California. In front are his trophies from Reno 2004.
Tom Aberle is a graduate of El Rancho High School in Pico Rivera, California. After graduation, he attended the nearby Northrop Institute of Technology where he earned his mechanic certificate with airframe and powerplant (A&P) ratings. Tom then acquired an inspection authorization (IA) two years later. He’s been involved in aircraft construction, modification, and maintenance ever since, and he currently operates Aberle Custom Aircraft, where he and his son, Jerry, dabble in all things aviation. Their company slogan: “We are purveyors of fine aircraft. We build, maintain, overhaul, and modify in nearly any way one might conceive—to provide for the improvement of the general aviation aircraft upon which we work.” The first plane Tom ever built was a 200-hp Pitts S-1S.
Before his education in the mechanical aviation arts, while still in high school, Tom took flight instruction from a man with a brand new flight instructor certificate—his father, Harry Aberle—and was the first student his dad ever signed off for solo. That was on Tom’s 16th birthday. Many years later Harry soloed Tom’s son, Jerry, as well.
At that time, Harry Aberle had an aircraft rental and flight school business at Compton Airport in California, and leased hangar space to some operators of aerobatic biplanes, including Harwood (Skip) Hellen, who owned a Stolp Starduster, and the late Bob Herendeen, who kept his first Pitts S-1 there.
A NEW RACE DIVISION IS BORN
During these early days, air racing promoters thought it would be a good idea to feature some less expensive aircraft at the feature races, something to help introduce pilots to the field and initiate them into pylon racing, as well as rounding out the racing schedule. After consulting with the best aerobatic pilots (who during the mid-1960s were sharing the Reno air race venue at Stead Field) a new class of biplane racers was conceived.
Biplane Class restrictions, which all entries must adhere to, included an engine not larger than 290 cubic inches at the time of the first biplane races in 1964. This was later increased to 320 cubic inches, and ultimately to the current maximum of a 360-cubic-inch displacement. A fixed-pitch propeller, a minimum weight of 500 pounds, and a wing area of at least 75 square feet (of which neither wing could be less than 30 percent of the total wing area), as well as several other physical attributes define the limits.
By the time the class was fully outlined, and several years into actual racing, the class began to look like the “Pitts Race,” as the only pre-existing biplanes on the market (other than the Pitts) that fit the design criteria were Smith Miniplanes, Mongs, EAA Biplanes, the original Knight Twister, and the Starduster One. None of these were really as popular, nor as prevalent, as the Pitts.
This 1987 photo of Tom and the highly modified Long Gone Mong was shot just after the return from a victorious time at Reno. The paint color was a coincidental match to Tom’s 1976 Corvette. Photo courtesy Aberle Custom Aircraft.
The Mong Sport biplane was designed, built, and first flown in 1953 by Ralph E. Mong of Tulsa, Oklahoma. Mr. Mong was a slight man, less than 5 feet, 3 inches tall, so the plane features a small cockpit, narrower at the shoulders than most other designs. The Mong Sport is a single-place open-cockpit steel tube and fabric biplane, typically powered by a Continental C-85 and capable of top speeds around 115 mph. The aircraft featured a 16-foot, 10-inch wingspan and an empty weight of 550 pounds. Tom chose to start with the more slender fuselage when he designed the No. 62 Phantom, as it benefits from lower drag due to less frontal area.
If you compare the early photos of the original Mong Sport (pictured below) with the Phantom race plane, it appears to be a completely different design, but there is a core section of the classic homebuilt aircraft right in the center. From the firewall to the seat back, the Phantom is pure Mong. The balance of the plane, however, is completely unique to this version, but wholly within the regulations for the Biplane Class.
Here’s an example of a stock Mong Sport. You can see that there’s not much resemblance to Long Gone Mong and virtually no resemblance to Phantom. This photo is courtesy of Ken Dayer, curator of the Jay Miller Aviation History Collection (housed in the Aerospace Library of the Central Arkansas Library System).
THE NEED FOR SPEED
The appeal of going faster than the other guy is one that touches many pilots, but some find a way to pursue those dreams and live life a little further out on the edge than the rest of us. Tom Aberle and his partner, Andrew Buehler, of Port Orchard, Washington, are two such fellows, and they have surrounded themselves with a small cadre of hard-working, highly motivated associates. Bob Busch was a consulting engineer on the project and made four trips from his Pacific Northwest home to work on the race plane, a week and a half per visit during the seven months of construction. Andy and Stewart Paterson, owners of Paterson Motorsports, applied their talents to various airframe and propulsion issues. Stewart became the liaison between the engine builder, Lycon Aircraft Engines, and the Phantom race team during the preparation of the powerplant. Ted Von Hirsch took responsibility for the horizontal and vertical stabilizers, and Thomas E. Harper was the primary wiring and electrics man. Jerry Aberle, Tom’s son (an A&P and IA in his own right, with a repair and maintenance shop right next door) stepped in to lend a hand as well. This talent pool makes up the Phantom Biplane Race Team.
The itch to race first got scratched in 1966, when Harry Aberle took his family to the Reno event as “crew” for their two hangar tenants. Herendeen was flying his Pitts S-1 in the aerobatic competition (he was named U.S. National Champion that year and again in 1969) and Skip Hellen was piloting the Starduster in the early races for biplanes. Tom Aberle was afforded the opportunity to fly Hellen’s plane around the course during the practice trials and gained his “race qualified” permit as a result. He got to compete in a 1967 heat race and then in 1968 to race in the major event at Reno, in Skip Hellen’s Starduster. Other race venues, including St. Louis, Missouri, in 1969, Porterville, California, in the late 1970s, and Mexicali, Mexico, in both January and December of 1980 served as great experience for Tom’s competition career.
Tom purchased Bill Boland’s old No. 3 Gone Mong and later damaged it, resulting in a rebuild by Tom, after which he renamed it No. 31 Long Gone Mong. Tom then campaigned at Reno in the late 1980s, winning the National Championship in 1987, placing second in 1988, and once again taking home the Championship trophy in 1989. (This plane was later raced by Patty Johnson under the new name of Full Tilt Boogie.) In 1999 and 2000, Tom was piloting a Pitts known as Class Action for an ownership consortium, and following that, Tom and Andrew Buehler started talking more seriously about a long-held desire to work together to create a highly competitive Reno air racer.
THE 2003 SEASON
The commitment was finally made on February 28, 2003. A deal with a sponsor was initiated that made it possible to consider competing in the Reno 2003 air races. When we asked Tom about the inspiration behind Phantom, he simply said, “I have been racing for a long time, and I wanted a winner.” A basket case Mong Sport had been purchased previously by Mr. Buehler, and Tom had already built the inverted gull center section into the fuselage truss. The intention was to rebuild the plane with enough modifications to give it an edge against the other competitive entrants.
A master planning session revealed that there simply weren’t enough work days available, while running an active aircraft repair and modification business, to get the entire project completed in-house within the limited time frame. Less than eight months remained before the 2003 competition at Reno. The obvious solution was to subcontract some of the critical component work to qualified specialists.
The expertly built Lycon engine, in the concrete reinforced test cell, ready to be hung on the test stand. Note the handmade, custom, cool air intake system.
Lycon Inc. of Visalia, California, is one of the most respected builders of aircraft engines in the world (www.Lycon.com). Its state-of-the-art facilities include two dynamometer test cells. It accepted the challenge of co-developing a race-ready, fuel-injected Lycoming O-360. This powerplant is fully balanced, ported, polished, and flow-bench tweaked as one might expect. Some of the features of this engine also include:
- 12-to-1 compression ratio
- Teflon polymer-coated piston skirts
- Ceramic-coated domed piston crowns
- Ceramic-coated dual valve springs
- Chrome rings
- Custom-made intake plenum and runners
The standard horsepower for a stock engine of this type might be 180 at 2700 rpm, measured without accessories. Phantom will turn this engine at anything from 3200 to 3570 revs (depending on the situation), and the owners will only state that it makes “markedly in excess” of 250 hp, at least for the duration of a six-lap tour of the pylons.
The rear view of the engine, showing a little more of the intake manifold. Photo by Lycon.
This engine was converted from the typical Lycoming cast sump system (which also pre-heated the induction air) to a remotely located oil sump and cold-air induction. “We put a flat plate where the sump goes with a small pocket at the back and an AIO-360 scavenge pump onto the accessory drive, and that evacuates the crankcase. The thing runs dry as a bone as a result,” Tom told us. The system is ventilated from the case to the external oil tank and uses an aluminum oil tank “borrowed” from the high-performance automobile aftermarket.
One of the major advantages with the dry sump system and the new remote oil tank is not all mechanical in nature, but rather aerodynamic. By removing the factory sump and moving it up and aft, behind the engine, Tom estimated that 20 percent of his flat plate frontal area is reduced.
The conversion was completed by the Phantom team while Lycon was finishing its expert magic on the custom build. Team Phantom traveled to Visalia, added its components to the long block, and Lycon moved the engine to its high-tech dynamometer test cells where the Aberle team observed the tests and results.
This overview shot of the engine shows the updraft cooling system, the Light Speed Engineering LSE ignition coils, the oil cooler, as well as the dry-sump oil reservoir.
Special note should be made that the class rules do not allow angle valve heads, which would normally be the choice of someone seeking higher power output. Parallel valve heads were used as required, but much attention was paid to optimize the flow of the air/fuel mixture. As a summation of the results of the expert head modifications, proven by the dynamometer results, we quote Kenny Tunnel of Lycon, who’s been dubbed “the king of understatement” by Tom: “Wow, I guess we got these heads figured out!”
The weight of the engine with all accessories (Tom doesn’t run an alternator), not including the remote oil sump itself, comes in at about 235 pounds.
With the Light Speed Engineering ignition system, a printed circuit board with a crank position sensor is one option used for timing. The other option (not shown) uses a Hall Effect Module, which is installed in the accessory case and senses crankshaft position by means of the non-impulse magneto gear.
Spark is provided by a combination of one Light Speed Engineering Plasma ignition system and one Bendix 1200 series magneto. The 1200 is the choice over the 200 as Tom told us, “Because it’s got a hell of a lot more voltage than a 200.” The complete electronic ignition system consists of two pickups at the prop, two coils, noise suppression ignition wires, and unshielded plugs. Tom said, “I used Light Speed on the last airplane I was running; I wasn’t all that convinced that it was a big advantage until I got this engine. Compression ratio on this one is such that it’ll blow out starters if it kicks. The limitation of the spark retard of the impulse coupling design, along with the possibility of non-impulse coupling action-ignition at normal advance, can be tough on starters.”
Photo courtesy Lycon.
The fuel-injection system is an off-the-shelf unit from Airflow Performance Inc. (API) of Spartanburg, South Carolina. The API system is not approved for certificated aircraft but is specifically approved for the Biplane Class at Reno. In fact, anyone who is competitive in the class runs the API system. When considering API, Tom conferred with Kenny at Lycon and asked why he should run it; he was politely told, “It flows more air.” That’s all Tom needed to hear. Phantom uses the standard model that Airflow Performance recommends for any Lycoming IO-360. This was chosen because it offers superior performance to the typical factory installed Bendix RSA-5 fuel-injection system. The API injection system has been proven completely equal to the task for this race engine.
Tom gave us a brief education on his injection system: “The Bendix fuel-injection system that’s used on aircraft and the continuous flow port fuel injection that’s synonymous with mid-1950s Corvettes are very similar. All they really do is monitor the airflow through a throttle body, through the use of venturis and ram air sensing, and control the air with a butterfly; so now you know how much air is going through the servo, and you’re controlling it. You vary fuel pressure across orifices that are in the nozzles themselves. That’s it. You feed the fuel out of the servo through a flow divider, the flow divider goes to the nozzle, the nozzles have an orifice in them that says, ‘under “x” psi, I will flow so many CCs.’ It’s simple and trouble-free.” The typical Bendix system uses fuel pressurized to 24-49 psi, as does the API unit Tom uses, as API specifies using the same pumps.
The primer lines on Tom’s fuel-injected engine caught my eye. Since this engine did not start out life as an IO, it was set up for a primer system and the heads were drilled and tapped for primer nozzles at the factory. Since there needed to be a port on the head in which an injector nozzle could be installed, it made perfect sense to Tom to employ the otherwise unused primer port to locate the injector nozzles.
“I sold my first airplane, No. 31 Long Gone Mong, and the gal who got it ended up racing it for several years, and she won with it in the early- to mid-1990s,” Tom said. “She managed to get an additional 6-8 mph out of the airplane by doing two things: First, taking the engine to Lycon and having them build it. And second, they took the Bendix throttle body and sent it to API. Don Rivera bored it out and made it into an Airflow Performance injector that looked like a Bendix.”
COOLING AND EXHAUST
Updraft cooling was chosen as the lowest drag method of moving the necessary air through the cowling. The flow has to make only two 90-degree turns, compared to the usual four turns made by standard downdraft cooling, which results in less restriction and lower drag. Cooling drag is a very significant factor for all airplanes, oftentimes summing to 30 percent of the machine’s total parasite drag. Tom reports that the cylinder head temps are still rather low, so more miles per hour may be obtained as the cooling system is further refined. There are five cooling relief vents in the upper engine cover, one for each cylinder, and the last positioned as the oil cooler outlet. See photo below.
The exhaust system is notably unremarkable. Tom started out with set of long, equal length, stainless steel headers feeding a four-into-one tailpipe that collected under the engine and exited between the landing gear (under the pilot’s seat). This more elaborate exhaust system was never actually installed because the firewall size advantage gained with the dry sump would be negated if these pipes were used. Dyno testing at Lycon revealed that the four-into-one netted an 8 hp gain at wide open throttle, but Tom wasn’t convinced that the extra drag would be worth it. So Phantom flew in 2003 with four straight stacks penetrating the cowl cheeks approximately 10 inches. For Reno ’04, Tom cleaned things up a bit, shortening the stacks and making them curve 90 degrees aft into the slipstream.
This Reno 2003 photo, shot by Chris Luvara, clearly shows the straight stack exhaust system Tom once used. www.StickAndRudderPhoto.com
The one-of-a-kind, high aspect ratio wings were commissioned from Grove Aircraft. Besides being very well-known in the experimental aircraft community as a provider of formed aluminum landing gear and brake systems, Robbie Grove also operates a first-class composites shop. Much of his work there is contracted to governmental sources. Robbie Grove is an EAA guy from way back and loves interesting challenges. Tom told us that Robbie has been building Formula One components and aircraft wings for quite some time. He agreed to take on the fabrication of the radical-looking wing sections.
The wings were constructed using custom-made carbon fiber box spars (main spar and drag spar), formed around 4.5-pound Clark foam, using a composite polymer thermosetting resin. This particular foam product is no longer available from the original manufacturer, so builders without a stockpiled supply must now use a heavier, but still available, product for similar applications.
The modified NACA 65 series airfoils were shaped using hot-wired foam blanks of Dow extruded polystyrene, as found on most Rutan airframes and many other plans-built and kit experimental aircraft. (Extruded polystyrene is not to be confused with white expanded bead polystyrene.) The shaped airfoil pieces were bonded to the previously assembled and cured spars, and this new assembly was then encapsulated with carbon fiber; two plies laid up at approximately 45 degrees from the spar for strength, plus a third layer encompassing only the forward third of the wing. The different composite resins and epoxies in use are post-cure compatible. All the fuel is contained within welded aluminum cells, so fuel resistance was not a specific concern. When using expanded polystyrene, keep it far from any chemicals (including gasoline) that can dissolve the foam.
The completed wing sections were delivered to Aberle Custom Aircraft and mated to the modified Mong Sport fuselage, now re-christened Phantom. The total wing area is just above the 75-square-foot minimum area requirement for the class, and features some unique aerodynamic qualities, which understandably, given the competitive nature of the owners, cannot be revealed at this time. One specific feature that can be shared is that this plane has a pretty high stall speed. Tom said it just quits at 80 mph, which he finds unusual, as all the other planes he’s flown with similar wing loadings usually stall in the high 50s to low 60s. Given the high aspect ratio wings, this seems fast for a plane that only weighs in at 738 pounds empty. This high stall speed makes landing at the home field, with its 2,165-foot by 60-foot runway, extra fun.
When we first saw the plane, complete with the ELIPPSE propeller (as reported on in the February 2009 issue of Experimenter), we couldn’t help but notice how the planform of the wing and propeller complemented one another. When we mentioned that to Tom, he replied, “As a matter of fact, when the two-bladed test prop arrived, I even said in a strange way it complements the airplane, and as I told a whole bunch of people last week, the airplane sits here in front of my desk, in the hangar, and it’s taken me almost a year to be able to look at it and see that it may be pretty. The airplane is so striking in unconventionality that it’s difficult for me to see beauty.”
Tom test driving the Mong Sport fuselage truss before hacking off the aft section for the carbon fiber monocoque tail cone and empennage. Photo courtesy Aberle Custom Aircraft.
The stock Mong Sport airframe was welded steel tubing from firewall to rudder. The fuselage was modified by the crew at Aberle Custom Aircraft by first installing the landing gear. Now the aft section is a carbon fiber composite monocoque shell, attached at the seat back of the steel tube cage structure that makes up the cockpit forward to the firewall. By removing the tail cone and propeller, the completed plane can be transported “side saddle” on a standard width, highway-legal trailer.
FUEL SYSTEM AND LANDING GEAR
Phantom is a pure racer but carries enough fuel to fly to races if the owners choose to do so. There are two welded aluminum cells bused together, totaling 14.7 gallons, in the space between the instrument panel and the firewall. This configuration was required in order to facilitate installation of the cells into the extremely compact space available. Race rules require a minimum capacity of 14 gallons, but the aircraft need not be full when racing. There are also two auxiliary fuel tanks of 2.5 gallons each, also bused together, located in the lower wing root leading edges, inboard of the wheels and the lower wing panels.
Photo courtesy Aberle Custom Aircraft.
The landing gear is composed of a welded steel square tube truss that is actually the root section of the lower wings, and the small aluminum reserve tanks are hidden there within the aerodynamic shell of the non-structural composite wing root fairing. They are designed to feed the engine directly through valves. With a grand total of nearly 20 gallons of avgas available, Phantom could be flown to events, but this is not a comfortable cross-country machine, being a very snug fit and with minimal instrumentation and no avionics at present.
When a race plane makes a quantum leap in performance, everybody takes notice. All of the Aberle shop crew’s work finally paid off.
Tom made many special arrangements with folks during the early weeks of Phantom’s development to ensure that the hurried production schedule could be met. One of these advance deals was to have a race prop built for this high-power, low-drag application. But something went terribly wrong with the prop maker’s production schedule, and the prop blank that Tom put on order in the beginning was not available when the time came to carve the prop to Tom’s specifications. When the Phantom group was ready to go racing the aircraft had no prop, other than the test prop used for the first flights and to gain data from which the custom prop would be designed. Tom was able to borrow a spare propeller from the Class Action No. 21 team. This was a 2- to 3-year-old unit but showed no signs of fatigue, so it was installed, personally torqued in place by Tom, and found to be satisfactory. In fact, with this borrowed prop, the plane set the highest qualifying time at Reno in 2003, but Tom felt that something wasn’t quite right, as the plane exhibited a “yaw hunt” at speeds faster than 200 mph.
Unfortunately, after this qualifying run in the 2003 series the Phantom group discovered there were screw heads missing and sheared off the spinner. Further inspection found there was damage to the hub section of the prop. Two of the prop bolts had zero torque remaining. The prop exhibited signs of failing under compression, and the “squirming” of the prop on the hub is what Tom attributed to the unusual yaw anomaly. Another mad scramble ensued, looking to find a suitable replacement prop for the next day’s heat race.
Biplane Class President Frank Jerant had a prop on his airplane that wasn’t doing as much for him as he thought it should, so he had replaced it with another. He agreed to let Tom use the one that had been removed. This prop was flight tested on the Phantom before competition, as required by race association rules. All went well, or so the group believed.
Tom ran the first heat of his class Friday and took the checkered flag. Upon returning to the pits, he killed the engine as he taxied up to where his son was standing. The first thing he noticed was Jerry’s face going sheet-white. The prop had lost about 2 inches of composite laminate off the forward face, near the tips.
At this point Tom had destroyed two propellers, neither of which he owned, and he was upset with the failure of the contracted prop maker to deliver the new prop that had been ordered so long before. In desperation, the crew looked in every hangar and shop area, and although many offers where made to lend the crew props, none of them would have made the plane go as fast as the two units that had already been sacrificed.
Tom told the sponsor, Chris Piedmonte of Eagle Creek Systems, “We have a choice; we have a plane that was built in seven months, and that’s a win. We have the top qualifier, and that’s a win. We finished first in our heat race, and that’s a win too. Now, anything I do at this point in time will produce a no-win situation, and possibly cause damage to something or someone.” With Tom having just safely survived the in-flight failure of two props, the crew agreed that they would retire from the event prior to the Gold Race. “Well, we went and got a whole lot of beer, cried for awhile, stuck around until Sunday, and enjoyed our little bit of laurels,” Tom said.
About a month after Reno 2003 was over, Jack Cox’s Sportsman Pilot magazine (known for a history of unparalleled coverage of Reno) arrived at Tom’s desk. He was pleased to see what he considered a very good article on Phantom. A few days later he received a call from Paul Lipps who shared some interesting ideas about propellers and offered to design a special prop for Phantom.
When Tom was approached by Paul, they had only a passing acquaintance. Paul is associated with Light Speed Engineering, the company that produces the popular electronic ignition magneto replacement, with which Phantom is equipped.
At the time that Paul read about the two prop failures that the high-rpm race Lycoming had endured in 2003 at Reno, he had been experimenting with an unusual propeller planform, which he believed might be able to assist Tom in realizing his dream of a championship trophy. A phone call got the wheels in motion with the loan of a two-blade experimental model, flight proven for both airworthiness and proof of concept on Paul’s own Lancair 235.
A BIT OF APPREHENSION
Tom and his crew had some misgivings about flying behind the unconventional-looking design. Their first impression was, “Is this thing going to work?” To add some pucker factor to the already dubious nature of this “first flight” endeavor, Aberle Custom Aircraft is located at Fallbrook Community Airpark (L18). This field’s only runway is less than 2,200 feet long by 60 feet wide, which is marginal to many pilots’ frames of mind, but to make matters worse, the strip is even more of an unforgiving place than the brevity of the airstrip suggests.
This high-speed taxi test shows the “carrier-like” runway at the Fallbrook Community Airpark. Photo courtesy Jerry Aberle.
It is carved from the top of a hill. There are no thresholds and no overrun area. The immediate area is surrounded by avocado orchards and expensive homes; not a swell place to be forced down. Southern California’s Interstate 15 is close by, but that might be more dangerous than the groves. The runway resembles a naval carrier, but without the benefits of arresting cables or catapults! This might not seem like the wisest choice of a place to test a new prop design, but then again, it probably wasn’t the best place to test fly a new race plane either. Tom, however, promised the ELIPPSE prop, even with its “slow start” feature, launches the Phantom before the mid-field marker.
Tom reported that the ELIPPSE-equipped airplane seemed a bit slow from the initial throttle-up point; it took a long time to get the tail up, but, “Immediately after liftoff it was like getting a boot in the butt.” When the wheels left the ground it pressed him firmly back into the seat, and he knew right away he had something special. It both out-climbed the previous props and was significantly faster at the top end!
Usually, a fixed-pitch prop will perform well in one regime or the other, and most folks not intending to race for a trophy will choose some blend of fair climb and good cruise. Not many props that we’ve heard of can boast a really super rate of climb and still deliver championship race lap speeds! Claims such as these are generally reserved for constant-speed props, but the Biplane Class does not permit those, so the ELIPPSE design is truly one of a kind.
The data gathered from these early flights gave Paul the information he needed to design a prop especially for Tom’s airframe/engine combination and its intended purposes.
Using the data collected by Tom while flying Phantom with Paul’s surplus two-blade prop, Paul used his computer program to design the planform and twist for a custom propeller, optimized for high speed and high rpm. A hand-carved, wood-laminate, composite-covered three-blade fixed-pitch ELIPPSE design was specified, and Mr. Catto was then engaged to carve the race prop.
As you may remember from the Paul Lipps article in the February issue, the ELIPPSE propeller makes thrust from the tip to the spinner. Unlike conventional props that make no thrust or even negative thrust at the root, Tom’s ELIPPSE propeller makes enough thrust at the root to increase the ram air effect on manifold pressure from the previous 1-1/2 inches over ambient with a conventional prop to a phenomenal 3 inches over. That’s 1-1/2 inches of additional manifold pressure free, which could easily translate to several extra horsepower, considering that it translates to approximately a 5 percent increase in power.
The propeller was drilled with an SAE-2 bolt circle, bored to accept 1/2-inch bolts (with drive lugs), which with the use of an aluminum squash plate, affixes the propeller to an 8-inch prop extension.
In reflecting upon his decision to take the risk and use this unconventional propeller, Tom said, “I have thought in the last couple of months—I wonder, I really do wonder—if conventional technology had not pooped on me last year, would I have embraced such an unusual-looking propeller as I did; I don’t know. I would probably have been hesitant; I’ve seen enough broken props, I’ve seen enough broken airplanes from broken propellers, but I was emboldened a bit by conventional technology crapping on me.”
Propeller designer Paul Lipps (left) and builder/pilot Tom Aberle (right) confer at Reno ’04, while enduring the mid-September cold. Photo courtesy Jerry Aberle.
When Tom returned with the same aircraft to the same race venue in 2004 he had made only two modifications. He had shortened the exhaust stacks, and he had a radical new Paul Lipps propeller.
Photo courtesy Craig Catto.
This propeller proved to be a significant contributing factor leading to even greater performance from an already amazing race plane. The 2004 Reno air races saw the No. 62 Phantom take on all competitors and leave them far behind. It posted the winning speed of 241.5 mph, a new race record.
2004 was the banner year for Tom Aberle’s Phantom biplane, where he obtained a qualifying speed increase of 20 mph over 2003’s record-setting speed. This was done while averaging 250 rpm less than in 2003, a 7.1 percent power decrease.
For 2005, a four-blade prop was designed and built that restored the 250 rpm deficit. Because of some problems that were later determined to be in the fuel system, it was decided to go with the previous year’s three-blade. This same year saw Jeffrey Lo, in his new Miss Gianna biplane, flying an identical three-blade ELIPSSE prop, with which he took first in qualifying at 237.403 mph. Phantom was being flown by Tom’s partner, Andrew Buehler, and qualified second at 232.71 mph.
Miss Gianna took the first heat at 224.043 mph, and Phantom was third at 205.303 mph. The positions changed on the second heat, with Phantom first at 216.018, followed by Miss Gianna a close second at 214.392 mph. The biplane Gold Race went to Phantom at 230.827 mph, and Miss Gianna placed second at 220.443 mph. Charlie Greer was flying his Formula One Miss B Haven (not in the Biplane Class) behind another ELIPPSE prop and qualified third at 249.099 mph, just behind David Hoover’s new Endeavor at 249.815 mph. This prop was not well-matched to Charlie’s drag and power, and he was never able to get the design rpm.
In 2006, Phantom, piloted again by Tom Aberle and with the four-blade prop, set a new qualifying record of 249.106 and won the Gold Race at an astounding 251.958 mph! Had they been using the course distance adjusted for the faster speeds of the Formula One racers, Phantom’s speed would have been 252.2 mph! Miss Gianna was no slouch either, qualifying at 241.136 and taking second in the Gold at 231.685.
Byline: Roger Brower, Bob Brown, and Tom Aberle
Yet another of the unusual four-blade ELIPSSE propellers is being built for Phantom by Craig Catto. This new propeller is expected to again set a new qualifying speed record at the Reno National Championship Air Races in September 2009.
Although Phantom now has about a 20-mph margin over the rest of the Biplane Class and exceeds the race record for the T-6 class, the next goal is to beat the speed of the IF1s (Formula One’s nemesis), proving the Biplane Class has the racer’s edge in breaking three class records: Biplane, the AT-6/SNJ, and IF1.
The Biplane Class had sort of been given a back seat in go-fast racing to the heavy iron until David Rose showed up in 1999 with his No. 3 plane and proceeded to win all the races and increase speed for each race. He ultimately qualified for a Pulitzer Award in Aviation during the Reno air races. Rose was beating the field in all of his races by half a lap in most cases with his new designs and an engine built by Eric Hereth. They ultimately achieved a race speed of 226 mph at the end of a string of four consecutive Gold wins from 1999 through 2003.
After winning the Gold Race in 2003, with a smoking engine and limited sight of the field, Rose had to land hot and used the entire Stead runway and several hundred feet of the overrun, ending up in the sagebrush at the end of the runway. Rose escaped with no injury, and the plane was in fairly good shape, considering the damage it sustained after flipping over.
Rose returned in 2007 to test a newer prop configuration using NASA inducted fan technology. On its initial test flight after reassembly for the races the plane, flown by Steve Dari, crashed in front of the stands after the engine quit twice, according to all the photo data that was recorded by the media present. Uncontrolled fuel metering was suspected as the cause.
We could have tested propeller design and concepts in 2007, and it may have turned out to be a real horse race between the Rose plane No. 3 flown by Steve Dari and Tom Aberle’s Phantom No. 62. As it turned out, Aberle went out to qualify for 2007 and set a new world Biplane Class qualification record of 251.597 mph, beating his 2006 race record. However, during the first heat pre-ignition occurred in the number four cylinder and melted the piston. A replacement piston and cylinder were hustled up to Reno by Phantom’s engine builder, Ken Tunnel, of Lycon Aircraft Engines. The piston and cylinder were fitted and the oil system repeatedly purged so Phantom was ready for the Gold Race on Sunday. However, on the second lap the number four cylinder again melted the piston. The cause was later determined to be improper spark plug selection, which caused the pre-ignition.
So the Aberle team watched the balance of the races from the pits, knowing they had set a new qualifying record and the airplane was not broken.
The teething problems that Phantom experienced from its debut in 2003 with propellers and then in 2007 with spark plugs were a good test to see what potential it held and how the plane would react to the newer racing speeds on the Reno course.
The results were impressive. The speeds they expected to get with the new props were even higher than expected. Pilots Tom Aberle and Andrew Buehler wanted to get some time on the prop to see what it would do if pushed to higher speeds and rpm, a very good idea as it turned out. Until the Lipps props, it was discovered the laminations were starting to bleed resins out, and operation at the speed range needed to sustain racing speeds were not going to be possible. After extensive examination of the propellers destroyed in 2003, newer production and curing methods were explored, and more carbon composite was used in the laminations along with the Lipps planform. The result was that most of the previous problems did not reoccur in subsequent testing and racing.
With wins in 2004, 2005, and 2006, followed by a broken engine in 2007, Phantom was back in 2008 with upgrades and won the event with a speed of 251.975. This year, a newer propeller design by Paul Lipps will be tried, which is expected to add perhaps 5 mph or more to the racing speeds on the course. Other modifications due to be completed are replacement of the landing gear wheelpants to reduce some identified drag points under the plane. Improved cooling in the engine compartment and profile changes to the ducting are expected to give even better cooling and performance.
Contact: Roger Brower
1007 E. Virginia Ter.
Santa Paula, CA 93060
Span: 19+ feet
Length: 18+ feet
Height (level): 6.5+ feet
Cockpit width: 20+ inches-
Cockpit height: 36+ inches
Never exceed speed: 290 mph indicated airspeed
Design cruising speed: 75 percent 200+ @ 2600 rpm
Stall speed: 80 mph
Rate of climb (estimated): 3,000 fpm
Ceiling: 25 feet above ground level
Fuel capacity: 19.73 U.S. gallons
Empty: 738 pounds
Dihedral: 0 degrees
Washout: 0 degrees
Sweep: 0 degrees
Incidence: 1+ degree
Dihedral: 1.5 degrees
Washout: 0 degrees
Sweep: 0 degrees
Incidence: 0 degrees
Deflection-up: 25 degrees
Deflection-down: 21 degrees
Deflection: 30-30 degrees
Displacement: 360 cubic inches
Max horsepower: 250+ @ 3xxx rpm (Classified)