Formula 1 Air Racing

 

 

"Fly Low, Fly Fast, Turn Left"

 

Imagine screaming low over the desert sage brush at over 200 MPH with seven other airplanes. That's the world of Formula 1 air racing. Formula 1 is the only air racing class who's airplanes are specifically designed for closed course air racing. The aircraft are all custom built in accordance with the "formula" specified in the classes design guide. The races are held on an oval course marked by pylons. Like their Formula 1 automobile "cousins," this results in airplanes which, while similar in looks have taken a variety of differnet steps to extract every once of speed while staying within the confines of the class rules.

The Formula

Formula 1 racing aircraft must be built and maintained in accorrdance with the classes Technical Specifications and Design Guide. Basically all aircraft must:

  1. Weigh a minimum of 500 lbs
  2. Have a minimum of 66 square feet of wing area
  3. Have fixed main landing gear (tailwheel or nose gear may be retractable)
  4. Have a fixed pitch prop of either wood or composite contsruction
  5. Use for power a stock Continental O-200 engine with magneto ignition system
  6. The pilot must weigh at least 170 lbs with flight gear on

 

In order to extract as much speed as possible from this formula, crews concentrate on three main areas in which to increase performance; aircraft aerodynamics, engine performance, and propellor efficiency. Over the years many different approaches have been taken. The bottom line is this however, Formula 1 race teams are going over 250 MPH on a closed race course using the same engine that will barely power a Cessna 150 to over 100 MPH. How is this done?
A major area of consideration of course is the engine. While the rules specify a stock engine there are things that may be done to improve performance. First, an engine needs to have all internal moving parts balanced and blue printed. This allows the engine to turn at over 4300 RPM. At such high RPM engine cooling becomes a serious factor. The Continental O-200 is a horizontally opposed air cooled engine. The design of air intakes and the ducting which routes cool air through the engine compartment is critical.The photo on the left shows the engine installation on Ed Bowe's beautiful, highly modified Cassutt "Miss Lynn." Ed's team has employed a cooling system which employs a welded aluminum pressure plenum around each cylinder bank. The air then exits through an augmentation tube which shrouds the 2 into 1 exhaust pipes. Ed's airplane along with Scotty Crandlemire's "Outrageous" have raised the bar in workmanship for all racers. While Ed's welded plenums are a piece of superb workmanship most other racers employ baffle systems which are made of either fiberglass or aluminum and held in place with rivets. screws, nutplates or a combination of the three. Some airplanes also employ round annular air intakes as opposed to the more traditional rectangular ones. The annular intakes promote a smoother airflow when the relative wind is not directly parallel to the intake. The bottom line is this; a well designed cooling system can contribute significantly to a race planes overall drag reduction resulting in higher speeds on the course.
Exhaust sytems are another area where the ideas and creativity of different teams comes into play. There basically three different types of exhaust setups. The first are straight stacks. While the simpilest this setup is not to be discounted. There is virtually no resistence to the flow of exhaust gasses coming out of the cylinder. Ray Cote's "Alley Cat," one of the perenially fastest airplanes on the course uses this system. Several aircraft also use a 2 into 1 setup where the two cylinders on each side of the engine are routed into a common pipe that exits the cowling. A 2 into 1 exhaust has the benifit of keeping exhaust away from the cockpit, a problem with short stacks. In addition an augmentation tube can be employed to accelerate the flow of cooling air through the engine compartment. The four into one tuned exhaust system is used in most of the faster racers. The benefits of a tuned system are obvious but the crew must offset the increased weight through the gains in engine power. The photo below of Birch Entriken's "Scarlet Screamer" shows his 4 into 1 system. It must work because Birch placed third in the Gold for 2003.

The racers wing is another area where speed can be improved. While the rules specify a minimum of 66 feet in area, planform and airfoil shapes vary to the degree that no two airplanes on the course will have the same wing. A stock Cassutt employees what is known as a "slab" wing which has a basic span of fifteen feet and a constant chord giving it a rectangular shape. "Zarrina" presently races with this type of wing. Other airplanes use wings of different shape and length. The double tapered wing is very popular and most of the Gold class racers have wings which vary in planform. The photos below show three racers with different type wings. On the left is Gary Hubler's "Mariah with it's double tapered fiberglass wing. Next is Roger Keaney's "Mojave Green" which uses a Wilson tapered wing. Below is Gary Dalleske's "Black Jack" which was 2003's fastest slab wing Cassutt placing 8th in the Gold.

 

 

 

The Race

  

 

The race itself is conducted around an oval course marked by seven pylons. The "home" pylon sits at mid field and is the point where race timing starts and finishes. Pylons are generally tall poles with either an orange/red and white drum on top or a light or flag. The course employ's a left hand pattern the start of the first turn being marked by pylon 1. Pylon 2 marks the midpoint in the first turn and pylon 3 the rollout point. From there we have a long straightaway to pylon 4 which marks the second turn. Pylon 5 is the midpoint of turn two and pylon 6 the rollout. The airplanes then continue down the straightaway past the home pylon to pylon 1. At Reno the race course is 3.11 miles in total length. Races consist of 8 to 10 laps. Pilots cannot fly below the height of the pylons which range from 35 to 75 feet above ground level. The shortest course is flown low and tight around the pylons. A total of 8 airplanes race at one time. As you can imagine eight airplanes flying that low and fast around the course presents an exciting spectacle.A day of racing begins with a mass brief shown in the photo to the left. This is a daily occurrence for the pilots and crews. Weather along with other operational considerations are brought to the attention of the crews. After the mass brief the racers have a class specific brief between the pilots and the Formula 1 Director of Operations. At this time procedures for launch and recovery are reviewed and any specific questions are answered.
About 30 minutes prior to the race crews move their airplanes out of the hanger and line them up just beyond the crowd line. From there they are towed to the end of the runway and "spotted" in their takeoff position which is determined by qualifying speed or speed in the previous days race. For the racers sometimes the most exciting part of the race is the takeoff. Formula 1 races begin with a "racehorse" takeoff. The airplanes line up in three rows. The first row consists of three aircraft. The second row, approximately 100 feet behind the first consists of two aircraft. The back row is three more for a total of eight airplanes. Once the airplanes are spotted the crews wait for takeoff. Engines are started at this time and engines warmed up. Crews hold the airplanes in position while the pilots check their engines. Three minutes prior to race start the crews leave the runway and at one minute prior the green flag is raised. When the green flag is dropped, brakes are released and the race begins.

 
Zarrina Being towed to the end of Reno's Runway 8
View from the front row, center lane looking aft at the competition

 
Roger Keeney's crew holds Mojave Green fast, just prior to the race start

 

Ed Dutreaux in Slingshot about to pass Jay Jones in Quadnickle
Zarrina rounding pylon 6

 

On takeoff all racers must maintain their "lane" until passing the home pylon. At this point all bets are off as each pilot bids into pylon 1. Passing procedures require that pilots pass to the outside and must always keep the passed aircraft in sight. Each aircraft creates a wake off from it's wingtips and churns the air behind it with it's prop. You need to watch the line other pilot's are flying and be aware that their "dirty air" can roll your airplane upside down in a hurry. This dirty air is generally felt around the pylons or when you tuck in tight to make a pass.

Each racer finds a "line" around the course and then attempts to fly the airplane as smoothly as possible. Any slip or skid through the turns dissapates airspeed. Also, contrary to what many people think the turns around the course are not made at high G loadings. Most of the turns are made at 3 to 3 1/2 G. As the racers roll into a the turns most pilots will look down at the ground for shaddows. This is how you can spot another airplane trying to pass. On the straights a glance is made to check the line to the next pylon and then a glance down the opposite straight to see where the other airplanes are. After the requisite number of laps, racers cross the home pylon to a checkered flag. They pull up and to the left climbing off the race course in a left hand pattern. All racers exit at the checkered flag even if they have not completed the required laps. Upon landing the aircraft are brought back to the pits, adjustments made. Then the aircraft are prepared for the next race.