National Championship Air Races
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Timing the Races

Sam Coleman, Timer

March, 2011

Unlimited Race Course
Unlimited Race Course

This page describes how we time the Reno National Championship Air Races. It is intended to be an technical overview, not an instruction manual or complete description of the races or its rules. For more information about the races, visit the Reno Air Racing Association at

There are six classes of racing aircraft: Formula One, Biplane, Sport, T-6, Jet, and Unlimited. Each class operates with its own rules; the Unlimited Class is used in the examples below.

Unlimiteds fly on the course shown at the right. After takeoff, the racers join up with the pace plane, which leads them to a left turn-in from Peavine Mountain, creating a line-abreast formation. As the aircraft come down the "chute", the pace pilot aligns the racers, by radio, and then releases them with "Ladies and gentlemen, you have a race!" As the aircraft cross the start line shown on the diagram, a race official turns on the start light atop home pylon.

Using video tape to time the races
The Timing Cameras
Home pylon is located at the bottom of the diagram, across the main runway from the grandstands. The racers make six to eight laps around the course, depending on the race, finishing at home pylon. Qualifying laps are on the same course. The timing team uses video cameras to time races and qualifying laps, from the timing booth in line with home pylon at the top of the grandstands. Two video cameras record each race, providing independent times for each aircraft.

At the start of the race, the cameras are focused on the start light which, when illuminated, provides a common reference mark on the race videos. There is a third, backup camera running in case a primary camera fails or becomes obscured by over-excited race fans.

The Timing Booth
The Timing Booth

Home Pylon
Home Pylon
Television Formats

Television was designed to display 30 frames per second. To reduce flicker, each frame was divided into two "fields", one containing even-numbered lines and the other odd lines, resulting in 60 images per second. More information had to be included between frames for color, and the government required that color signals be viewable on black and white sets, so the frame rate was slowed to 29.97 frames per second. This made a one-hour video run a few seconds too long. To compensate, frame numbers 0 and 1 of the first second of each minute, except on ten-minute boundaries, are skipped. (No video frames are skipped, only the numbering jumps.) When we time the races, we compensate for the dropped frame numbers.

Timers start the cameras before each race, and watch for the signal from the Starting Judge's signal light. When the signal is flashed, they yell "MARK!" and the excitement begins! The cameras display the time of each frame of the recorded video, with values to the nearest 1/60th of a second (see the Television Formats sidebar below). Each camera crew notes the approximate starting time that they observed on their camera. Aircraft passing home pylon are recorded on tape, documenting the race positions for each lap. Each camera crew also notes the approximate finish time. After the race, the crews review the video from each camera to identify the precise frames showing the start of the race and the finish for each racer. Lapped aircraft receive finish times, with the actual laps flown used to compute their slower speeds. If required, individual lap times can be retrieved from the tapes. The start and finish time marks for each racer are input into special software that checks the independently recorded results from the two cameras. If there is a difference, as little as 1/30th of a second for any aircraft, the data is rejected and the video tapes are reviewed. If the time discrepancy cannot be resolved, the results from the third camera are called in.

It's not possible to identify individual aircraft on the video. During filming, "spotters" call out the race numbers as the aircraft pass home pylon. The audio is recorded on the video tapes and "recorders" write them down. Race numbers are recorded for each lap to identify aircraft being lapped. After the winner crosses the finish line, the race is over for each aircraft as it passes home pylon, so lapped aircraft fly fewer laps than the winner.

As the timers step the tape to identify starts and finishes, they see two images per frame, the fields described in the Television Formats sidebar, each representing roughly 1/60 of a second. Unlimited aircraft, at 500 mph, can travel over twelve feet in that time, so timers interpolate tenths of fields to further refine the results.

After recording the camera start times, the timers fast-forward the tapes to the end of the race. For each racer, they step the tapes to get the exact time that the nose of the aircraft crosses the finish line. The difference between the starting and ending camera times yields the elapsed time and, with the length of the course and the number of laps flown, the speed for each aircraft:

Speed = (Start lap length + (Number of laps flown - 1) * Lap length) / Elapsed time

The Evolving Timing Technology

From the first races until 2003, races were timed with stop watches and skilled pairs of eyes. Timers sat on a platform next to home pylon built by Vic Hollandsworth. (The white platform is visible to the left of home pylon in the photo above.) Several timers clocked each race. Vic correlated the times and phoned the results to Debbie Giese in the Scoring Office. Debbie calculated speeds, computed penalties, and published the race reports.

Sandy Goldstein
Sandy Goldstein
Excel Timing File
2006 Excel Timing Form
Tom Gribbin and Joe Lacey collaborated to modernize the timing. Many sports calculate the speeds of athletes or vehicles using laser gates to start and stop clocks. Aircraft racing on three-dimensional courses don't lend themselves to this timing method. Cars, boats and athletes can break a laser line to start and stop clocks, while aircraft can cross a line at any altitude, rarely tripping a laser beam. Video recording solves the problem by clocking aircraft as they cross a vertical plane representing the start/finish line. Experts in the field of video imagery demonstrated their ability to time racing aircraft traveling over 500 mph.

In September, 2003, an experimental team gathered to videotape and time the races. The video timing was accurate, easily compiled, and reviewable if questions arose. The system proved its worth that year. In one race, for example, video showed an aircraft winning by inches, too close to call by eye. Just like the evolution of the instant replay systems used in many sports, air racing had come of age. At this early stage of video timing, spreadsheets (left) were used to convert times to speeds. The spreadsheets were printed and faxed to Debbie at the Scoring Office. The timing values were reviewed and re-typed for official posting.

Race Data Window
Race Data
(click on any image to enlarge)

Select Function Window
Main Window

All of this did not lend itself well to the real-time data demands that modern race fans deserve. The author, a timer since 2001, volunteered to develop a program for the timing and scoring teams. The resulting software, written exclusively for the Reno Air Races, delivers the timing reports directly to the scoring office, correlates speed, penalties and other vital statistics, and posts real-time updates on the official race web site.
Racer Data Window
Racer / Pilot Data

Debbie works with class representatives to correct errors and document anomalies in the reports. Debbie then declares the results official and publishes the reports. The official reports replace the draft reports on the web.

Some of the windows supported by the program are described in the following paragraphs. Timers enter data about the races and the racers before race week. The race-data window lets them list and edit race schedules, and includes details of the previous qualifying and race records. This data, modified if records are broken, appears on various reports.

Similarly, the racer/pilot window allows timers to enter registration data for each aircraft. The record for Race 31 is highlighted in the example, allowing timers to edit the data for a P-51 named "Speedball Alice". It lists the primary pilot, alternate pilots, and data about the aircraft. Pilot names and home towns are selected from pull-down menus, populated from a pilot database. The pilot database covers all race classes, since pilots often fly in more than one class, and the database is used from year to year to reduce the number of clerical errors.

Speed Calculator
Speed Calculator
During race week, the main window allows the user to select qualifying or race windows for any of the race classes. It also contains buttons to send the data and report files to Scoring and to the web, and to create or print reports as records are broken. The "Speed Calculator" button allows timers to compute speeds to answer special questions, based on camera times or manually-computed time intervals. The example shows that an aircraft completing the Unlimited Gold race in exactly eight minutes will have flown an average speed of 502.434 mph.

A change in one report can change other reports. For example, changing a race result can change the report for every pilot and every aircraft in that race, the pairing for following races, and might change the report of race winners or new records. The program produces over 400 reports, over 1,000 files, for a single race season. The "Update All Reports" button keeps all of these reports consistent. When invoked, it re-generates all of the reports. It saves the new or changed reports and sends the appropriate files to the web and to the scoring office. If no reports have changed, re-generating and checking all 400 reports takes about one second.


During qualifying periods, Monday, Tuesday, and Wednesday morning of race week, pilots on the course ask, by radio, to be timed for one or two qualifying laps. Unlike races that use the start light, qualifying laps start and end at home pylon. Timers enter the camera times into the qualifying window.
Qualifying Window
Qualifying Window
Unlimited Qualifier Report
Unlimited Qualifier Report
The qualifying example shows that Steven Hinton, in Race 7, made two qualifying runs. His second attempt is detailed on the screen for editing. When Race 7 passed home pylon to begin the run, the camera time was zero hours, 18 minutes, 48 seconds, and 7 frames. The camera operator noted that it was the second image of frame 7 (field "b"), and estimated that the actual start time was two tenths of a field later. The camera time at the end of the first lap is also shown (Steven flew only one lap each time). Steven cut no pylons and was not disqualified. A pylon cut disqualifies a lap. The wall-clock time of each attempt is recorded, important when records are broken.

The example shows the elapsed time and corresponding speed for each attempt. The faster of the two qualifying laps flown, 484.255 mph, is used for Race 7's qualifying speed. Timers can also add comments, to detail pylon cuts or explain other anomalies. This window also allows the user to create the full qualification report for the Unlimited class, a report of the qualifying laps flown that day, and detailed reports for Race 7 and for Mr. Hinton.

Qualifying laps are filmed by just one camera, so the other can be off-line to process times for previous qualifying runs.


During race days, Debbie creates race "pairings", listing who will compete in each race. The contestants for the initial races are determined by their qualifying times. Subsequent contestants are determined by prior race results. Each class defines its own "progression" rules to determine how races are populated. During the races, the software can recommend pairings for each race. The process, however, cannot be completely automated since, in some race classes, pilots pick their own starting positions within a race. If an aircraft breaks down and is repaired, there are
Pairing Window
Pairing Window
Joe Lacey
Joe Lacey Extracts Time Values
special rules to allow it to enter subsequent races, and race class officials have discretion to fill races.

The example shows the pairing window for the 2010 Unlimited Gold 3A race. At the bottom, Debbie can display qualifying data, any prior race or, in the example, the results of all of the previous races in decreasing speed order. She can add a racer in the table to the race by clicking on it. Entries with a "+" by the pilot's name have alternate pilots. If an alternate pilot is scheduled to fly the aircraft in this race, Debbie can change the pilot with the pull-down menu. To the left is a column of pull-down commands, allowing Debbie to delete entries, promote or demote them, etc. She can also create the pairing report from this window. Pairing reports are widely distributed, electronically and on paper.

Races are timed as described above. The camera values are entered into the program on the result window. The racers from the pairing record carry forward to the result window. (If a last-minute substitution is made, and a racer does not appear on the result window, Debbie can modify the pairing for that race, which corrects the pairing report and updates the result window.)

Results Window
Race Result Window
Gold Heat 3A Results
Gold Heat 3A Results
The wall-clock starting time is recorded. The start times from both cameras, which apply to all racers, are entered on the left of the window. Then, each racer is selected, in turn, so the user can enter the timing information for that racer, including the ending camera times. The program computes the elapsed time for both cameras and compares the values. (In the example, the times from the two cameras, for Race 7, differed by three milliseconds.) The times are averaged to show the final time, in this case 6 minutes and 21.146 seconds. If the difference between the cameras exceeds 30 milliseconds, the program highlights the discrepancy, usually caused by a data-entry error. If this is not the case, the camera crews go back to the tapes to check the camera values.

The number of laps flown and the pylon cuts are recorded for each racer. The "Set Defaults" button sets the laps flown to the number of laps in the race and clears the pylon cuts, since this is typical. In the example, racers 7 and 77 lapped the field, so the record shows that they flew six laps while the other finishers flew five. Race 5 had mechanical problems and pulled out of the race after 4 laps, so the record shows that he "did not finish".

Participants have one hour after the unofficial reports are published to protest the results. Debbie can click "Start One-Hour Timer" to cause a message to pop up one hour later. If no protests have been filed, she marks the race official.

The timers can add comments for each racer to, for example, document pylon cuts or other anomalies. They can also include comments about the race in general, to describe the weather, explain why a race was cancelled or delayed, etc.

Available Reports
Available Reports
Printable Results
Printable Report
The program displays the reports for a class, and allows the user of the program to generate, update, display, or print one or more reports. The sample on the left shows all of the Unlimited reports for the 2010 race season. Clicking on a report updates that report, if necessary, and displays it. Multiple reports can be generated and/or printed by setting their check boxes. The sample on the left shows that all of the reports are available except for the Gold pairing and result reports.

The reports are generated as "html" files, the language of the web. The program converts these files to the "pdf" format to produce printable reports. The program also creates dynamic race class pages which show the web visitor what reports are available. Reports are available to everyone seconds after they are produced, and typically less than 30 minutes after the last aircraft passes home pylon.

Comments, corrections, questions, and suggestions are always welcome. Please use this form to send email to the author.

Reports can be accessed on the web at: