FORMULA FORUM THE IF1 JOURNAL

FORMULA FORUM THE IF1 JOURNAL JANUARY / FEBRUARY 2011

FORMULA FORUM IF1 INC. Formula Forum 2011 International Formula One Pylon Air Racing, Inc. All rights reserved. Formula Forum is the official publication of International Formula One Pylon Air Racing, Inc., a Texas non-profit corporation. Member of the Air Racing Council of the United States. Published bi-monthly. DISCLAIMER FORUM CONTRIBUTIONS MEMBERSHIP RULES WEB SITE Articles appearing herein may be edited and are the opinion of the authors and not necessarily the opinion of IF1 Inc. Send contributions to: Editor, Lista Duren 3233 Via Alicante #48 La Jolla, CA 92037 Phone: 858-452-7112 Cell: 858-442-1811 E-mail: lduren@pacbell.net All contributions remain property of Formula Forum. Membership in IF1 is open to pilots, owners, crews and technical people active in Formula One Air Racing for $60/yr. Anyone may join as a non-voting Associate Member, $35/yr. Applications available from the secretary or on-line. For IF1 Technical and Procedure rules, check on-line at: www.if1airracing.com Jim Cunningham, Webmaster jjam_n262@netzero.net COVER PHOTO Scarlet Screamer stabilized for laser measurements. The API laser tracker, used to make the thousands of cowling measurements, is visible at lower left. (Stephen Pearce photo) Inset: HP prop master in mold-making fixture at Twisted Composites. (Steve Hill photo) EXECUTIVE COMMITTEE DOUG BODINE President 6299 East Highway #44 Rapid City SD 57703 605-393-7112 president@if1airracing.org BRIAN REBERRY Vice President 4632 W. Garden Court Boise, ID 83705-3985 208-724-6841 brian@reberryairracing.com DAN PETERS Secretary/Treasurer 1438 Morningside Dr, Longmont, CO 80504 720-308-1596 Dan Peters [dan@route66raceteam.org] DIRECTORS JAY JONES Promotions Committee Chairperson P.O. Box 761 Buena Vista, CO 81211 719-661-4484 Quadnickelracer@gmail.com Volume XXII Number 1 CONTENTS TOM DEHART Technical Director 5220 Walton Dr. Klamath Falls, OR 97603 541-882-1589 flyfastflylow@fireserve.net BOB BEMENT Operations Director 7320 Old Stage Trail Kelsey, CA 95667 530-622-1434 rbement@wildblue.net KIRK MURPHY Pilot Committee Chairperson 6140 Christa Lynn Pl. Prescott, AZ 86310 928-710-3105 murphyk79@aol.com JOHN HOUSLEY Technical Rules Committee Chairperson 1020 Chesterfield Forest Dr. Chesterfield, MO 63005 314-518-8542 f1race43@gmail.com TOM WATKINS Procedure Rules Committee Chairperson 10120 Brookpark Blvd. #313 Calgary, Alberta T2W1E1 Canada 403-607-8457 ezetom@gmail.com 3 President s Page Doug Bodine 4 VP Report Brian Reberry 5 Sec/Treas Input Dan Peters 5 Pilot s Notes Kirk Murphy 6 The Hill Pearce Racing Propeller Birgitta Nurmi 17 Letter to the Editor: Race Pairings Bill Rogers 17 Calendar 18 IF1 Marketplace 2 FORMULA FORUM, JANUARY / FEBRUARY 2011

If you are reading this because you are interested racing as a participant, vice spectator, you are on the right track. IF1 is probably the most painless path to that goal, financially and otherwise. Some points to help you focus your efforts and make them productive for getting you in the races: 1. You Make sure you are ready. You must enter this sport with a safety focus. No other concerns can distract from this mind set. You need to be sure your tech, piloting, or crew skills are ready. As an owner, you set the environment for the team. It must be prudent. You cannot push to cut corners; your team will sense it and oblige. As a crew member, study the rules and tech data on the aircraft. A fun way to get up to speed is to shadow a vet. As a pilot, you will be up there by yourself. If you don t have any high performance taildragger time, you need to find a good instructor and a plane to get some familiarity with the Cassutt type flying characteristics. It is nothing to be intimidated by, but it is different from commercial and even combat flying, and if you fail to respect that, you will get bitten. Formation flying if you have none, you need to do some before even considering a race. You don t need years of experience, but you need some, and not the Jim-Bob, the local CFII, says to do it this way kind of experience: Get it from someone who knows what they are talking about. You need to know your blind spots and danger areas. When you are comfortable doing rejoins, wingwork, crossunders, trail and breakouts, then you are ready. Not a huge time and $ commitment, but it is huge in terms of importance. Put it this way: if you can only rationalize $40K for racing, don t buy a $40K racer. Buy a $30K racer and put a few thousand into training and a few thousand into spare parts. Keep the rest on hand. You will have a better racing experience, as will your fellow racers. Finally, once you get your racer, fly the heck out of it. Do everything you can think of that will apply to racing unusual attitude recovery without altitude loss, dead stick landings, low altitude flight, wake turbulence and stall handling drills. We all have flight profiles if you want to try one. It is fun, and you will build confidence. It is such a great excuse to fly and have fun. 2. The Race Plane You can build, you can buy a sport plane and racerize it, or you can buy an existing racer. You will want to talk to veterans to make this decision, and if you build or modify, you want to have a person you can discuss things with. There is a design guide on the web site www.if1airracing. com that is very good about spelling out the requirements. Like the pilot requirements, they are not cosmic, but they are important. You just need a little attention to detail, and things will work out well. If you don t, you get to learn by trial and error. You can get there, but it is not as fun. There are racers out there, and we can help you find the right one if you want. Continued, bottom of page 4. President s Page Photo by Bill Rogers Doug Bodine Once you get your racer, fl y the heck out of it. FORMULA FORUM, JANUARY / FEBRUARY 2011 3

Vice President Report Brian Reberry Encourage each other to blow off the dust and get the airplanes ready. Photo by Bill Rogers I m not sure about you, but it s cold and I am ready for spring! That said, it is a great time to start working on the race modifications for the next year. Like most, our team usually procrastinates until later in the year only to realize that there is never enough time to get everything accomplished by September. I encourage, or even challenge you to have you racers flying by early summer so we can have a full field in the hangar this year. Please communicate with your fellow racers to see what is going on and to encourage each other to blow off the dust and get the airplanes ready! Trust me in that I understand the challenges involved. Our new racer is coming along. It will be a momentous leap to make it happen in time, but by gosh, we are going to try! The Formula One board of directors and committee members have been diligently working to sort through several technical rule proposals submitted recently. Many of the proposed rule changes are well thought out and researched, but before they go out for vote, the committees have to sort through and make their recommendations. From there, they may go out for vote among the current IF1 membership. If and when these proposals come to you for a vote, please consider the reasons why the proposals are being presented. The ideas are hoped to encourage new innovations, remotivate the group, lighten the tech inspections, and make it easier for the incoming rookies. It is my belief that change can be good to motivate and make it exciting again. Get to work on your race planes! Brian Reberry Jay Jones crew readies the plane for the Gold start in 2010. 4 President s Page (cont.) 3. The crew If you are thinking about racing, think about building and managing a race team. Racing is fantastic, but putting together a team of great folks and spending a week in Reno with them is equally rewarding. And it is easy people want to be there, and they will be thankful for the chance to be part of it. There are a bunch of floater crew members also, if you need an extra person or specific expertise. FORMULA FORUM, JANUARY / FEBRUARY 2011 Photo bybill Rogers Again, like the aircraft, talk to a vet to get the scoop. Get familiar with the regs; they are pretty simple and well aligned with the common sense vector, and the subject matter is interesting, so it is not painful to learn them. As soon as you start building a crew, introduce them to the rules. They will learn autonomously also and will back you up, which is reassuring and very helpful when things get busy. Feel free to call me, or any other veteran racer with questions or issues. We all love to talk about Formula One air racing. There is nothing else in the world like it. Doug Jethro Bodine President, IF1 (605) 393-7112

As I write this, February is already upon us and we are just around the corner from PRS. The dates for the 14th annual Pylon Racing Seminar are Wednesday the 15th of June through Saturday the 18th. I just spoke with RARA this morning and they are launching a completely new website that should be up and running by the time you are reading this. The new website will have the 2011 PRS Participation Package available for download. We need to work collectively as International Formula One Air Racing members, family, and friends to promote the sport that we love. Our class needs more participation from all sides and PRS is the perfect place for that to start. I am hoping that we are able to reach out and get more involvement this year. We all know that Formula One is capable of filling the field, so I would like to make it a goal that we DO! There are plenty of planes flying that are race legal, so lets all encourage Renewal notices for 2011 have been sent out. If you did not receive one, then please email me. We have a Paypal account set up which should be easier to use, especially for the international members. Our bank accounts are still in a state of transition, but hopefully this will be completed over the next few weeks. some participation by spreading the word and get some new blood involved and seasoned veterans back. Please have anyone with interest call or email me. I plan on instructing once again in the Glasair and I will do my best to twist John Housley s arm to come and put on his famous ground school. I know of at least one new rookie coming in June, rumors of some returning veterans coming back for practice and possibly one or more NEW formula racers planning on some testing. Assuming we have the need, additional instructors will be available to teach PRS but it is still too early to forecast who will be at PRS so planning for instructors will come in the months ahead. I hope everyone s 2011 is off to a great start. Spring will be here before we know it, so get your airplanes out and Fly! Kirk Murphy murphyk79@aol.com (928) 710-3105 Pilot s Notes Photo by Birgitta Nurmi Kirk Murphy We all know that Formula One is capable of fi lling the fi eld. Secretary/Treasurer Report We are working on uploading all current IF1 documents to the new web site. This should allow members access to all the rules and IF1 s bylaws as well. Blue skies and tailwinds, Dan Peters Photo by Lista Duren Dan Peters Photo by Lista Duren IF1/Biplane hangar after the IF1 Awards Banquet in 2010. FORMULA FORUM, JANUARY / FEBRUARY 2011 5

The Hill Pearce Racing Propeller Birgitta Nurmi is an air race writer and photographer who enjoys the people of IF1 and their passion for the sport. She has worked as a psychologist, college teacher, athlete, musician, and park ranger. Photo by Lista Duren At the beginning of race week, 2008, Scarlet Screamer s new propeller was shrouded in its standard Twisted Composites cover. Few people knew about the new prop design, and the team wasn t talking or showing it off. The best way to keep a secret is to not let on that you have one. In one short year, the Screamer team had designed and produced one of the few new propeller designs in fifty years. This is the story of the new Hill Pearce (HP) racing propeller, the achievement of a few talented, competent, and innovative men. What is unique about this new design is that, unlike the Sensenich design which is a compromise in response to various requirements, this new prop was developed with the singular goal of increasing IF1 race speeds. The story starts with an enthusiastic and rather talkative guy named Jack Norris. During the 2007 races, Norris was scurrying about the IF1 hangar trying to get people interested in his book Propellers the First, and Final Explanation. This self-published thick paperback with the yellow cover presents the development of propeller math and theory starting in 1865. Jack Norris collected and integrated all the information which he considered to be at risk of being lost. Norris has considerable aerodynamic and aeronautical experience, including working as an engineer on Rutan s Voyager team. He became interested in propellers when he was a champion model builder. While testing hundreds of competition props for models, he concluded that tapered tip props outperformed the more typical broad tip designs. Now a spry 81-year-old, he remains passionate about propellers. Norris found a willing ear when he introduced himself to Stephen Pearce, Gary Davis crew chief. Pearce says of that initial meeting, We were busy loading up the trailer and getting ready to leave when Jack Norris came along. Since Gary and I were already looking at ways to optimize what we had, and evaluating the changes we could make, I was willing to listen to what Norris had to say. We chatted and I bought his book. I read it on the airplane on the way home and determined that yes, he had something there. Jack Norris did extensive research on propeller design theory. His book about propellers was the starting point for Stephen Pearce s design. 6 FORMULA FORUM, JANUARY / FEBRUARY 2011 Photo by Lista Duren Pearce was particularly intrigued by references to the work of Theodore Theodorsen, who wrote Theory of Propellers (McGraw Hill, 1948). So after he exhausted the information in Norris book, he read all that he could find of Theodorsen s original work. In October 2007, Gary Davis and Stephen Pearce decided to proceed with the development of a new race propeller. Pearce was confident that he could design the propeller, but who would build it? Steve Hill was

an obvious answer. But with only 10 months to complete the project they had to get right to work. In mid- October, Davis stopped off at Twisted Composites near Albuquerque for an initial meeting with Hill. Steve Hill agreed to build the mold and the propeller prototypes. He knew that Davis team had the necessary experience to tackle this project, and that Davis was willing to do the test flights, which was crucial. In addition, Hill hoped to end up with a new and better race propeller for the IF1 pilots. Meanwhile Pearce remained in touch with Jack Norris who sent him the computer program that Andy Bauer, Norris friend and colleague, had developed. Unfortunately Dr. Bauer, who had been an aerodynamicist at Douglas, Long Beach, CA, was not able to assist on this project, as he was starting to suffer the affects of Alzheimer s disease. Therefore Pearce had to rewrite the computer program on his own to adapt it to modern computers. As he worked with the program, he made some corrections. Pearce explains: I am an old engine builder. I ve always enjoyed operating at the leading edge of what the rules allow us to do. Professionally, my field is numerical math and I am a computer programmer that s what my business is. Thus when I took the time to look at Bauer s program, I figured out what the math could do. I also understood that you had to be able to map the cowling, then use that data to design the prop. He added I thought that designing and making a new prop would be less of a job than making changes, for instance, in the fuselage. As it turned out, there was nothing easy about the process. In retrospect Pearce concluded, The prop turned out to be a huge endeavor. By the end of October 2007, Pearce was ready to consult with Steve Hill about the details of building a propeller from an entirely new design. Hill immediately listed the tasks that needed to be done to correctly design a prop using Theodorsen s method. Only then would it be worthwhile to build a mold and then a new prop which would truly put Theodorsen s theory to the test. Hill s list of design tasks appears on the following page. The list was a reality check for Pearce and a glimpse of how involved the process would be. He was not intimidated, however. He understood immediately that this list of show stoppers as he called it, was the best starting point that Hill could have given him as it detailed the questions he had to answer before the propeller could begin to take shape. Another factor that played a significant role in this story: Pearce really enjoys a challenge. With a chuckle he explains, It keeps me from getting bored. So the process began in earnest and Stephen Pearce set out to do the impossible because I needed to have this prop built. The first task Pearce tackled was to measure the engine s horsepower and torque. A race engine s actual horsepower is not known, but he thought he had a pretty good idea what by Birgitta Nurmi FORMULA FORUM, JANUARY / FEBRUARY 2011 7 Photo by Lista Duren Photo by Birgitta Nurmi Stephen Pearce measured the cowling, designed the propeller, and milled the onebladed master prop. Steve Hill guided the design process, built the mold from Pearce s master, and produced the prototype propeller.

Steve Hill s List of Difficult Design Considerations Pearce says this list is best characterized as tasks that might be beyond the capabilities of some people. Yet they need to be accomplished to successfully design a prop. What is the horsepower output of the engine? What is the speed at which the aircraft will operate and what is the thrust required to overcome drag at that speed? What should the diameter of the prop be which will allow the engine to run the desired RPM? How will the important take-off performance be addressed? The Theodorsen math that yields the blade angle and chord dimensions is diffi cult. Slowdown analysis requires a 3-D map of the cowling. Rankine Source-Sink analysis to perform the slowdown analysis is mathematically complicated Even with a prop design, an aluminum master must be made Just because a prop design is optimal doesn t mean it is buildable, practical, or even safe to fl y. When the prop is made someone has to be the fi rst to fl y it. Who will risk their life on a prop that might not work anyway. The fi xed pitch prop is a compromise at best. it could be. He conducted a sensitivity analysis using his approximation of the horsepower, 15% more than that, and 15% less. As it turned out his guesswork was pretty good. He also found there is a big penalty for overestimating the hp, while underestimating it does not make as much of a difference. So he settled on the lower value. Then Pearce went on to calculate the slowdown factors. He explains, With a fixed propeller there are performance factors in initial acceleration and at the top end of performance. The fixed pitch prop is a compromise at best. So every factor that influences the fixed pitch propeller needs to be considered. One of the factors relevant to performance is the way in which air slows down as it passes near the fuselage. Therefore what needs to be determined is the average slowdown factor at each radius, as though the fuselage and cowling were a single body of rotation. The very center of the prop the first six inches is covered by the spinner. At this point the cowling is in the closest proximity to the prop. This means that the air can get past the prop but is slowed down the most. Moving out to the periphery, as the cowling and canopy recede, the slowdown factor decreases until there is no cowling behind the prop and the air flows at the speed that the airplane is going. The implications of this are that if you take this slowing down of the air into consideration, you have to change the theoretical pitch of the various portions of the blade to something much different. When using the effect of slowdown, the pitch changes up to 17% near the spinner and to 0.3% at the tip from what it would have been using just a theoretical analysis without slowdown. In order to calculate the slowdown, Pearce needed the exact shape of the cowling. So he clamped the plane firmly in place and mapped the cowling using an IFM/ADM laser tracker. In operation, the laser tracker continuously measures the distance to a hand-held retroreflector accurate to a thousandth of an inch. By moving the retroreflector along the cowling, Pearce was able to collect thousands of point locations relatively quickly. It took many thousands of differential measurements to produce an accurate 3D model of the cowling. He analyzed the data using the Rankine Source- Sink concept. 8 FORMULA FORUM, JANUARY / FEBRUARY 2011

Once he had collected all the information, Pearce started working on the propeller design. Using the theoretical analysis, corrected for the effects of slowdown analysis, he determined the chord and blade angles. He defined stations at 6%, 12% and so on, and calculated what the angle of the blade needed to be at each station. Pearce was working with one half of the propeller, from the center of rotation out to the tip. Hill had developed a method to make propeller molds using only one blade as a master. This not only minimizes the machining time and cost required on the master; it also results in some of the most symmetrical propellers ever built. Symmetry is an important factor for smooth running, high speed, high RPM Formula One racer props. On March 12, 2008, Hill received the first design data from Pearce and started the work at his end. Pearce had supplied him with a simple list of chord lengths and blade angles at 11 stations along the length of the blade. Hill modeled the blade using Ashlar Cobalt 3D solid modeling software with the chord lengths and blade angles per Pearce s design. He selected airfoils and thicknesses for each station from the NACA 44XX family of airfoils (plus a special tip airfoil). He then blended the blade into the necessary hub shape. At the same time, he developed the structural design of the propeller. Ten days later this job was done and the CAD models were on their way to Pearce. Pearce started to prepare for the next step: machining the parts. He purchased three aluminum slabs 36 Photo by Stephen Pearce inches long, 4 inches thick and 6 inches wide, each weighing over 85 pounds. Working with a friend, Pearce intended to cut the master propeller out of one of these slabs. That work began on May 4, 2008. But before Pearce started that process he spent some time looking very closely at Hill s drawings. It was then that he became aware of something quite unexpected and so different that it concerned him. Pearce explained, What I saw was that the propeller tips were awfully thin. How easily would they break or flex dangerously? The ramifications are horrible. If you lose 2 off the prop in flight, the resulting vibration can tear the engine off the mount. And someone is going to be testing this thing and that person is a childhood friend of mine. He knew that prop loading goes to zero at the very tip. If the tip is wide, it creates a vortex, which manifests itself in noise and turbulence. So he knew that the prop needed to be smaller near the tip if it was to function efficiently. Pearce concluded that, since the data checked out, he had to trust it. Scarlet Screamer s fuselage is fi rmly clamped to three supports to hold it absolutely still for cowling measurements with the laser tracker. It took many thousands of differential measurements to produce an accurate 3D model of the cowling. FORMULA FORUM, JANUARY / FEBRUARY 2011 9

Roughing required two setups: Machine the first side, then release the tip end from the vice and rotate the rotary table holding the hub end 180 degrees. Grab the tip end with the vice again, reset the machine s coordinate system, load the next software segment, then machine the second side. Repeat all of this for the finish milling. Roughing the blank took two setups. Finish milling took two more. In all, it took about 16 hours to shape the single master propeller blade on the threeaxis Fadal 8030 mill. The mill gouged the edge of the nearly fi nished prop master when the team loaded the wrong software segment. Photo by Stephen Pearce The details of Hill s drawing were entered into the Mastercam software program to create the instructions to drive the CNC mill used to cut the master prop from the aluminum block. It takes a big mill to chew through nearly 85 lbs. of aluminum to make the master. Pearce had a friend who runs a business with a three-axis Fadal 8030. The bed is nearly seven feet long and the mill weighs nine tons. Normally, it costs several hundred dollars an hour to get time on this kind of machine. One of the extraordinary facts in this story is the motivation of the people involved. Pearce s friend took his milling machine out of the production schedule for four days so that he and Pearce could continue their quest to build the perfect prop. Cutting a master propeller out of a slab of aluminum was hard work that required precision and total focus. Pearce mounted the hub end of the aluminum blank on a rotary table and clamped the tip end in a vice (as shown in the photo on this page). He mounted table and vice to the mill bed. Photo by Stephen Pearce Each setup took time, particularly resetting the machine s coordinate system. Then there were tool changes when the cutting tool got dull, broke, or once, when the tool got loose in the tool holder and destroyed itself. When the mill was running, coolant spray controlled the heat generated by the cutting. Over many hours of work, the shape of the new HP propeller started to emerge. The gremlin struck late at night when they were nearly finished. Pearce and his friend had worked all day and both men were tired, but they decided to push on. So when the time came to change the setup, they looked at each other and, with few words, they repositioned the work piece, loaded the next software segment, and re-started the mill. For Pearce the memory of that moment is vivid: We heard a loud pop followed by a spine chilling cacophony of screeching thumps and bangs. They stood in shock as the machine cut a large gouge through the blade of the propeller. They were horrified to find that they had loaded the wrong section of the program. With the air races not far in the future, Pearce and his friend started the mill- 10 FORMULA FORUM, JANUARY / FEBRUARY 2011

ing process all over again with another block of aluminum although not that night. By the end of May, they were done despite the speed bump. Pearce commented dryly, Nobody had told us that what we did was impossible. Had we known how difficult it was to make the machine master, we would not have done it. An aluminum master is almost impossible to produce but we got it on the second try. We were told afterwards that this was fabulous. Someone who knew about making those types of molds indicated that 10 tries would usually be more like it. Each attempt took 16 hours of work at the milling machine. On June 3, 2008, the master prop arrived at Twisted Composites. The surface was still a bit rough and showed the machining marks. Hill immediately set to work on the three critical preparatory tasks: After about 21 hours of preparatory work, Hill was finally able to turn his attention to making the mold itself. This undertaking consists of twenty separate procedures, each subdivided into smaller tasks. It requires about 80 hours of work. In July 2008, Hill was ready to use the mold to build the prototype propeller. This is another very involved process requiring fifty layers of graphite fabric in the hub area of the prop and approximately eight layers in the blade area. Then the rest of the propeller is filled with strands of carbon fiber going from tip to tip. The entire process of building a propeller can take more than thirty hours. Nobody had told us that what we did was impossible. 1. 2. 3. He sanded and painted the prop to make it completely smooth since all surface imperfections would transfer to the mold. He scribed stations on the body of the prop. These are marks along the edge of the blade, measured from the center of rotation in 3 inch increments. They serve as standard locations for measuring and comparing prop angles. He glued tiny wires (.015 inch in diameter) to the scribed locations so that the production mold has barely perceptible grooves. These grooves transfer the station marks to the finished prop, providing a consistent set of locations for future prop measurements. Photo by Steve Hill Photo by Steve Hill Steve Hill smoothed and painted the master (above) before using it to create the mold (left). Station markings are visible at the leading and trailing edges of the master. FORMULA FORUM, JANUARY / FEBRUARY 2011 11

Steve Hill used the single blade prop master to make the four-piece mold shown above. When assembled, this mold was used to create the one-piece prototype propeller (right). Crew chief mentality...i like to have spares of everything. Compared to the props Hill regularly makes, there were some aspects of this prototype that required special treatment. The differences were mainly related to the thin tips of the prop. He knew that this was the optimal aerodynamic design for a race propeller. But one question lingered: would the thin tips hold? While Hill was busy in his shop, Pearce rebuilt Scarlet Screamer s engine. He also tightened gaps between the cowling and the spinner for better alignment. This meant he had to fill the old mounting holes with carbon fiber and drill new mounting holes. Then he realigned the cooling ducts. In mid-august 2008, Pearce received the long awaited package from Steve Hill. When he unwrapped the new HP propeller he was amazed at what he held in his hands. It looked so elegant and so fast! Also, you need to understand, I had Photos by Steve Hill only been working with one half of the prop. That was all I had ever seen of it. But here was this complete propeller in shiny black carbon fiber. His idea had become reality. A second propeller was already in progress and would be sent out to them as soon as it was done. Not one but two? Crew chief mentality muttered Pearce, I like to have spares of everything. The next step: in-flight testing. Time was short now, and the team did not yet know what they really had. Only the actual flight-test could tell them that. A quote credited to test pilot Tex Johnson, applies to this situation: A flight test is worth a thousand expert opinions. Mid-morning on Friday, August 22, 2008, Gary Davis, Stephen Pearce, Pearce s friend, and a few others, met at Coulter Field, in Bryan, Texas. There were thunderstorms all around them so weather was going to be an issue. Another problem was that the runway was closed for construction and the narrower taxiway had to be used as the runway. Nevertheless they decided to go ahead. Pearce had built two new engines. They were as good as can be. We mounted a standard SH prop (54-65) to break the engine in and establish performance standards. Then we mounted the new prop. Gary and I had already talked about this. If this prop comes apart, I would prefer that it happen on the ground. So we ran wide open for 30 seconds. I stood in the prop line and saw the prop tips extend forward about 2 inches. Gary s thought was 12 FORMULA FORUM, JANUARY / FEBRUARY 2011

that if it s going to come apart, it ll do it now. But it held. We repeated this process twice. We checked for heat. Everything tested out fine. The team was nervous, especially Pearce. But Davis said he just felt excited as he looked forward to the first flight. He said that he had total confidence in Pearce. Davis had been involved in flight testing earlier in his career. He said, You just have to approach it very rationally. You have to know every step of the way what you d do if something went wrong. It s not like at the Reno races where you re 50 feet above the ground which allows little room for error. At Coulter Field, I could get up at altitude which gives me more time and more choices if something were to go wrong. If a tip were to break, it might tear the engine apart. But with a retaining cable you might not lose your engine altogether and you might still be able to bring it down. But the most important thing is: you ve just got to be ready for anything. Pearce strapped a parachute on Davis and gave one last instruction: If you re up high and the prop comes apart, you get out. Davis got into the cockpit and steadied himself. Pearce swung the prop and started the engine. Everything sounded good. Time to go and do this. Tension rose. Pearce had written a test profile that was seven minutes long. Davis rolled out and prepared for take-off. I climbed up, got it up to race RPMs, approximately 4000 plus, and then I got it back down so we could look at it. He shut the engine down and rolled up to where his team was waiting for him. He looked very pleased as he climbed out of the cockpit and told his team, This is the smoothest race prop I ve ever flown! The engine was running more RPMs. The test profile for the next flight was doubled to 14 minutes, and then increased for each subsequent flight. After each flight the crew meticulously examined the engine as well as every fraction of an inch of the new prop. But the airplane and the prop were not all that demanded the small group s attention. They also kept a keen eye on the thunderstorms. They timed the thunder and lightning so they would know how close the storm cells were. Fortunately there was enough of a window between storms to allow for the test flights. In late afternoon they started the fifth and final flight of the day. This flight was scheduled to be the longest one at thirty minutes. Everything had gone perfectly, exceeding all expectations. There was no reason for concern. But near the end of the flight, Davis noticed a few raindrops on the windshield. Oh, oh, not good he thought to himself. He knew that rain is potentially fatal to composite propellers. However Davis was ready for this, too. He tells the story like he might describe having breakfast: So I just turned off the engine and deadsticked it in. It was such an easy thing to do. I just shut the engine down, lined Photo by Bill Rogers Photo by Lista Duren This is the smoothest race prop I ve ever fl own! The thin tip profi le of the new propeller (top) contrasts with the traditional square tip racing prop (bottom) from Jay Jones racer. FORMULA FORUM, JANUARY / FEBRUARY 2011 13

So I just turned off the engine and deadsticked it in. It was such an easy thing to do. up with the runway I had plenty of altitude and just glided it in. Then he added, but it was a good thing that I didn t radio to Stephen what I was doing. He chuckled, I think those folks on the ground might have gotten very nervous. When Davis put the plane down, the team knew that they had made aviation history. Perhaps in the eyes of some it was a small piece of history, but the group knew what they had accomplished: They had done what others said could not be done. Davis was very pleased to find that the prop accelerated like a climb prop, that the take-off run was 11 seconds, and that it also flew as efficiently as a fast race prop. There was no vibration whatsoever. And the super thin tips? They held. How did Davis feel after that day was done? Thirsty, he replied laughing, Texas is pretty hot that time of the year. And of course we were excited. But the excitement was muted. We had fully expected that everything would work out. September 9, 2008: Qualifying. Normally Davis consulted with Pearce about the qualification profile, i.e., the perfect line of flight. Their usual consultation did not happen this time. Davis, thinking that the new prop might require a different strategy, decided to loosen his normally tight line on the race course. That turned out to be less than optimal. The qualifying time was 237 mph, and the crew was taken aback. We all knew we could do better than that. Davis now realized that he was not only flying for himself. He was also flying for the people who had put in an incredible amount of energy, time and effort; who had sacrificed a chunk of their lives in order to develop this new prop. He was deeply disappointed. September 11, 2008: Heat Race 1A. Davis was ready this time, but he had to deal with the fact that, as a result of the lower qualifying time, he was in 6th position. This meant that he was on the inside on the last row. There were five planes in front of him and two to his right. Crew member Gene Hubbard times Scarlet Screamer s qualifying laps. Photo by Lista Duren They went for a quick bite to eat at a nearby restaurant and Davis drove the three hours to go home. The work was done. Now the group was looking forward to taking this airplane on the race course at Reno. Everything else they needed to do was really just preparation to go racing. Come early September, they packed up Scarlet Screamer and trailered her to Reno. On September 8, 2008, she took to the skies again for a few practice laps on the race course. Everything continued to check out perfectly. He was totally focused. The green flag went down. The planes were off. Davis knew what he had to do. This was to be the most exciting race of my career. I was on the edge of the cliff with that one. It was a gamble to do what I did. It was a very busy start. As you know, with the IF1 starts, there are a lot of airplanes going for the same point in space. Doug Bodine was in the lead. Smokey and the others were on the outside of Bodine. I tucked in on the inside of Bodine. I flew real tight on the pylons. That kept 14 FORMULA FORUM, JANUARY / FEBRUARY 2011

me inside and safe from everybody else. I tucked in there and kept going. I did most of the passing in the first 45 seconds, before I got to Pylon One. All the passing I could do was completed by the time I reached Pylon Three. All I had to do now was fly a tight course for eight laps to finish second, which I did at 238.42 mph. Davis admitted: Yes, it was quite the debrief afterwards. Passing on the inside like I did is not a technique I d recommend to anyone. There was, and still is, a lot of controversy about that strategy. But the prop did great! Davis continued: We always called the Twisted Composites 55x62 the Shotgun Prop. It accelerates like you were shot out of a gun. The new HP also accelerated like a Shotgun Prop. And that is what allowed me to make it to Pylon Three ahead of six other airplanes in that heat race. But, unlike the 55x62, the top speed of the new HP prop was right there with the fast Gold race props. Now the cat was out of the bag, word raced around the IF1 hangar that there was something new happening in Gary Davis pit. In Heat 2A Davis was able to stay with front runners Bodine and Senegal and finish third in spite of a faulty start. In the Gold race, Screamer s performance matched Yellow Peril s performance throughout the race, and Davis took second place, beating Doug Bodine by 0.467 seconds. With the new prop, Screamer s speed increased by 10 mph over his 2007 speed. This story does not end here, though. Three HP propellers continue to accu- Photo by Neal Nurmi Photo by Lista Duren mulate air time. The prototype is still on Scarlet Screamer, now owned and raced by Vito Wypraechtiger. After the 2008 races, Hoot Gibson test flew the second HP prop on his Cassutt. He sums up the results: I certainly got increased performance. It was actually faster than any prop I ve ever run, probably 10 mph faster. It certainly accelerated faster. There seems to be more thrust and horsepower coming from that prop. Gary Davis races the new HP propeller in 2008, Heat 2A. Scarlet Screamer moved up from 5th in the Gold in 2007 at 229.032 mph, to 2nd in the Gold in 2008 at 239.332 mph. The team that did the impossible: Steve Hill, Gary Davis, the HP prop, Stephen Pearce, and Jack Norris. FORMULA FORUM, JANUARY / FEBRUARY 2011 15

While this is a very promising design, it is still a highly experimental prop with minimal history. Doug Bodine raced an HP prop on Yellow Peril in 2009. Gibson s written test report is available on the Twisted Composites web site at www.twistedcomposites.com/twisted_ Composites/Gibson_Report.html Smokey Young also tried the second prop on Sly Dog but elected not to race with it in 2009. Doug Bodine purchased a third HP propeller from Steve Hill and flew it on Yellow Peril in 2009. Steve Hill points out that there is still much to be learned regarding the practical nature of pure Theodorsen propellers. He says, There was a huge investment by the team to produce this prop, but how much do the cowling shape corrections contribute to the performance? Can the priceless master be used to make props of another pitch (by rotating the blade relative to the hub) or does a new master need to be created for each pitch? Hoot Gibson indicated that his cowling is very similar to Scarlet Screamer s, but Smokey Young, who has a very different cowling shape, reports not finding much difference using the HP propeller versus his customary prop. At this point, the dynamics of the propeller with different cowling shapes are unclear, but one thing is obvious: If the production of each HP propeller requires the exact fuselage configuration of the racer it will be used on, then this becomes a pricey and complex venture. What is known, however, is that Steve Hill has invested many years of his time and money to develop and build propellers that have been proven to be safe, and his is the propeller that most IF1 competitors are currently running successfully. To Steve Hill, safety is imperative and he is not willing to compromise on this. For those who might be considering flying the new HP prop on a racer, Steve emphasizes that, while this is a very promising design, it is still a highly experimental prop with minimal history. Meanwhile, there is a small group of people for whom this project is finished. Stephen Pearce has the satisfaction of having done the impossible and he didn t get bored while doing it! The participants in this project achieved what they set out to achieve. They managed to push the edge of possibility a bit further out there. And they did this for the sheer joy of being engaged in a very challenging process. They had to solve new and complex problems every step of the way. The process of innovation was their mountain to climb. They did it because the challenge was there and they knew they could. Photo by Lista Duren Editor s Note: Do you have a technical story to share in the Forum? Contact Forum editor Lista Duren (full contact info on inside of front cover) 16 FORMULA FORUM, JANUARY / FEBRUARY 2011

Letter to the Editor: Reno Race Pairings Perhaps we could have done a better job at Reno if we had used a different pairing system from that which was adopted this year. The small entry (15 reduced to 13) forced a consensus of pilots and operations people to adopt a complex volunteer system to fill the field for 9 races. It was a tribute to pilots and crews that this was accomplished without more problems. As a result we had three real races with the fastest aircraft for the A heats and Gold, three races with 5 aircraft and 3 non-racing fill-ins and three runwhat-you-brung, race if you like, demo races. As a result we raced the fastest aircraft with the slowest (90 m/h closing speed is not the safest), left aircraft in the hangar, required multiple hot refuelings/starts and damaged our credibility as a racing organization. It was probably a good thing that 90% of the crowd arrives after we have finished. I think that decisions were made because the majority of pilots have never experienced races at sites other than at Stead, where smaller fields are the norm and could not think outside the Reno box. Reno wanted at least 7 planes per race; 9 races means 63 starts. If we want 8 plane finals, say 65 starters. We had 13 planes, fly each 5 times and you have 65 starters! Here is my suggestion. Wednesday to Friday everyone flies in a 7-plane fast heat or slow heat and we use one different volunteer per day to provide 7 in the B heat. From those 6 heats, the fastest 7 go to the Gold plus the winner of the Silver to make 8. For the Silver, the 6 slowest are joined by 1 or 2 more volunteers. Run the Silver first on Saturday so as not to Photo by Lista Duren jeopardize the aircraft. The Bronze (rename as the Medallion race) can be run second, made up from Gold race volunteers or Silver racers that turn around after their race. The result: all races are real except the Medallion race and fill-ins are almost eliminated. This has been used before at Reno but let s hope we never have to use this again. Bill Rogers Send rebuttals or discussion to the Forum editor for publication in the next issue. (ed.) Pilots before the all fi ll-in Bronze race in 2010. Shown here: Jay Jones (Quadnickel), Dave Roelofs (Pooder), Steve Senegal (Endeavor), Philip Goforth (Knotty Girl) and Dan Peters (Route 66). Not in photo: Jim Jordan (Miss Min), Doug Bodine (Miss Demeanor), and Holbrook Maslen (Judy). Now Jun 15-18 Sep 14-18 2011 Calendar by Bill Rogers PRS information available on the RARA web site at http://www.airrace.org/pylon- RacingSeminar.php Pylon Racing School at Reno Stead Field Reno Air Races Contest committee member Bill Rogers has been involved in Formula One air racing since the early 70 s. Starting as crew, he has served as newsletter editor, president, and most other IF1 board positions. Editor s Note: IF1 historian, air race photographer, and Forum contributor Al Wimer passed away on October 21. We will run a tribute and retrospective in a future issue. Please send remembrances or contributions to Forum editor Lista Duren (contact info on masthead) FORMULA FORUM, JANUARY / FEBRUARY 2011 17

IF1 Marketplace AIRCRAFT FOR SALE Prior to purchase of any aircraft, please contact the Technical Director for any IF1 rules or compliance items that apply. Miss Demeanor, N96SR, Race 96 Race ready FLYING Formula One: Battery, Alternator, Starter, GPS, GRT EIS, MicroAir Radio and encoding transponder, NEW CYLINDERS AND PISTONS IN 2005, ENGINE OVERHAUL by LyCon in 2006 W/ NEW CASE, CRANKSHAFT, VALVES, ETC. Twisted Composites race prop. Sturba cruise prop. Uninstalled tapered horizontal stabilizer and elevators, produced by Craig Catto, designed to fly with Miss Demeanor s tapered wing. Sport fly during the year, race at Reno in September. Win the Silver, fly in the Gold! All for $35,500. Contact: Steve Senegal (650) 346-6967 ssenegal@sanbrunocable.com PROJECT PARTS & PRODUCTS CASSUTT PROJECT Stock wing, aluminum gear, Cleveland brakes. Contact: George Budde (405) 733-1449 patbudde@earthlink.net Formula 1 Race Engine. EXP 0-200-12. LyCon O/H in 2002. Fast on Scarlet Screamer but hasn t raced since a piston was holed at the Nellis demo race in 2005. Cylinders redone and engine recently inspected and reassembled with new stock pistons (picked to weigh within 1 gram). Engine Log with LyCon O/H entry. Includes intake from spider to cylinders and oil tank. Install your own electronic ignition (or mags), race carb, exhaust and go race. $10,000 OBO. Contact: Gary Davis at texasflyer@hotmail.com 940-458-5515 (home); 940-206-3079 (cell) Formula 1 racing treasures accumulated over almost a decade of air racing. Too much to list... Your choice: Various Twisted Composite Carbon props; DeMuth and other wood props; Cato props; Carbon Spinners; Carbon and Aluminum Spinner Bulkheads; 4 to 8 5/8 Prop Extensions and misc. Spacers; 4 into 1 Exhausts; M40J and other Spark Plugs; Misc. Parts, Hardware and Instruments. Call or email for parts list and details. Contact: Gary Davis at texasflyer@hotmail.com 940-458-5515 (home); 940-206-3079 (cell) F1 Race 98 & 99, accepting best offer on both aircraft including almost new Lycon engines, 3 Twisted Composites props and wood sport prop. Contact: John Hall 210-241-7378 or via email jhall@jetav.com CASSUTT WANTED Looking for an entry level, basic Formula One airplane to race at Reno. Must comply with IF1 technical rules. Contact Ira Saligman: (610) 324-5500 (Philadelphia) isaligman@saligman.com Cassutt Racer Aircraft Kit/Project Plans. One piece wood spar. Welded fuselage frame (factory welded). Rudder complete Horizontal Stab to be completed. All wing ribs complete. Aircraft plywood for wing covering. Fiberglass canopy frame. Steel landing gear with Goodyear brakes, tires & tubes. Sufficient aircraft tubing, wood and plywood to complete the project. $3900 Contact: Laslo Zamolyi, Jr. Home: 610-746-2618 Cell: 610-746-2618 zamalama@aol.com EAA Chap. 70, EAA Technical Counselor 18 FORMULA FORUM, JANUARY / FEBRUARY 2011

If you have aircraft or other items for sale, or updates to your listing, please email Brian Reberry: brian@reberryairracing.com Ads are free as a service to members Continental 0-200 stuff for sale: Slick 4381 mag with induction gear $500 SAF-Air quick drain oil tank valve in package $20 Two flowed cylinders complete with valves and covers, grooved and need honing $150 each Tach housing with cover plate $35 Oil screen housing with screen $25 Push rods $5 each Contact: Adrian Coop Cooper 604-328-1431 cooperairracing@gmail.com NAC Aircraft Display Mat (20ftx20ft) Plastic vinyl windscreen material with steel grommet boarder. Available colors: yellow, red, orange, green, blue, white, and black. Storage Bag Included Price: $300.00 plus ground shipping Contact: Tim Neubert 727.538.8744 TNeubert@airportnac.com NEW COMPOSITE PARTS Light Weight 9 Spinners, $90 Wheel Pants, $350. CASSUTT PARTS: Assorted Tail Feathers, call for Quote. LED Flashlights: Super Bright, Compact Size. Up to 155 hrs. of run time on 2 AA Batteries, $32. 10% Discount to IF1 members Contact: Ray Sherwood (530) 626-6106 rayyjayy@aol.com Cassutt Projects and Inventory Cassutt 111M, 90% complete. Needs cowl and wing finished. Includes REBUILT engine. Cassutt 111M fully welded with tail assembly. Cassutt 111M wing needs skin. Cassutt 111M wing complete. Misc inventory: engine parts (3 O-200 engines), airframe parts and instruments, one sport prop. $15K for all. Contact: Gary and Linda Elliott for pics and inventory list: 972-264-3857 lfelliott@att.com Grob Glider Also Volkswagen Beetle, Mill, Lathe, Camper, Engine for the Corba Kit Car project he started. Contact: marylemmond@yahoo.com. CASSUTT PARTS National Aeronautics has Cassutt parts including Aluminum and Steel landing gear legs. cassutt.lornet.com Contact: Ib or Sue Hansen (303) 940-8442 cassutts@aol.com Graphite Race Props Run One or Follow One Twisted Composites, LLC www.twistedcomposites.com Contact: Steve Hill (505) 832-1148 or (505)321-6467 carbonprop@mac.com AIR RACING BOOKS by Robert Hirsch Aircraft of Air Racing s Golden Age 1928-1939, 2 Volumes, 1071 pages, 158 scale drawings: $75 + $10 S&H Wedell-Williams Air Service $20 + $3 S&H Schneider Trophy Racers Goodyear and Formula One Racing (thru 1995): $45 + $5 S&H for both, or $25 + $3 S&H for one Free S&H to IF1 Members Make Checks to Maria Hirsch 8439 Dale St., Buena Park, CA 90620 Contact: Maria Hirsch (714) 828-7369 FORMULA FORUM, JANUARY / FEBRUARY 2011 19

Roughing the master for the Hill Pearce propeller, first used on Scarlet Screamer, Reno 2008. Photo by Stephen Pearce FORMULA FORUM 3233 Via Alicante #48 La Jolla, CA 92037