'84 speed record still stands

Model Airplane News, Dec 2000 by Hill, Maynard

C pylon racers do 170mph! Fan jets go 200mph! Giantscale racers do 220! Turbine jets can do even more!

Is this just hangar talk, or are these claims true? If they are true, why hasn't the world speed record of 150.1mphset by a model called "Tortoise" 16 years ago-been beaten?

I've published articles on almost all of the 23 world records I've set in the past four decades, but I suspect it will be news to a lot of modelers that the world speed record is "only" 150mph.

On November 28, 1984, John Patton as contest director and I as pilot successfully flew that tiny model around the 800m closed course in a record time of 11.91 seconds. We went out three days in a row with a huge crew of officials before we achieved a circuit without any pylon cuts and with measured times that met the FAI rule: two watches must agree to within i/so second.

That may be the first reason that the record still stands. The FAI rule on this is senseless. One-fiftieth second is lho percent of the measured time. One-or even two-percent should be sufficient precision for a record. Two people in front of a simple signal arm won't match to within 1/50 second more than about 10 times out of 100. The problem is worse with a model over a sight line.

Ah, well ... a rule is a rule! Pylon cuts and unmatched watches voided many, many circuits in the three-day trial. We eventually lucked out, getting around the pylons with no cuts with two watches that read exactly the same: 11.91 seconds.

Why else is this record so hard to beat? The rules limit engine size to lOcc, 0.61ci. This rules out giant-scale racers, turbine jets and a lot of swishy fan jets that use larger engines. Q40s or leftover Formula One racers are perhaps the best bet, but I don't think they go fast enough to beat Tortoise.

I can hear the speed experts shouting, "What? How can you say that?"

Well, let's look at the basics. The FAI closed speed course consists of four pylons on the comers of a square. Each leg of the square is 200 meters long. Only one circuit is required to set a record. The pilot can have turn callers with flags, radios, etc., but it is still hard to fly the course without cutting a pylon or traveling past them. The difficulty with depth perception is worse than it is on a pylon course where the pilot is close to two of the three markers.

So, 11.91 seconds for 800 meters computes to only 150.1mph. But after much study of the data for nearly 75 passes, I concluded that the distance flown on the winning circuit was about 950 meters, and the model's airspeed was between 175 and 180mph.

The 3-view shows that this model was a little smaller than Formula One pylon racers and, at 420 square inches of wing area, just a bit bigger than Q40s. The engine was an OFS .60, a top-rated screamer of the '80s. There was no cowl around the engine, but it was fitted with a tuned pipe. The wing was only 9-percent thick. I strove for a small frontal area. Drag for drag, I estimate Tortoise matched a polished pylon racer. (Trust me; no coefficient gibberish will be included here.) I used a Top Flite or Grish Brothers maple 10x12 prop-a favorite of the control-line speedsters of the day. We used 40-percent-nitromethane fuel. When the pipe worked right, the prop turned about 21,000rpm in the air. The pipe didn't always work right; it was pretty tricky to throttle down between passes. We usually made five circuits on each flight but had to slow down and circle overhead between attempts to allow timers and judges to get ready for the next pass. It was wild, wild fun! The crew all agreed we'd break either the record or the model before calling it quits!

What about using a pylon racer to beat this record? Well, Rich Verano holds the U.S. AMA record for Formula One pylon racers with 10 laps in 59.7 seconds-150.7mphin 1994. In 1999, Tom Scott set the current record for Q40 racers at 59.8 seconds150.Smph-in Bowie, MD. Using the measured length of 2.5 miles for 10 laps, these values are nearly identical to Tortoise's record.

I am sure both Rich and Tom flew tighter courses than I was able to, and this supposition translates to even lower airspeeds than Tortoise's. My guess is that they were doing about 170mph. Thus, if a standard pylon racer is to beat Tortoise's record, it will take a better pilot than I was in 1984, and I was no slouch back when I had good eyes! A more fruitful approach would be to fit a pylon racer with a Screaming .60 and tuned pipe in place of the .40, although a .60 engine might exceed the FAI's maximum allowable wing loading of 24.5 ounces per square foot. You'd have to add wing area, and then the plane would too big to go fast. The secret to speed is a small plane with gobs of power. A delta is a good bet if you can accurately steer it. The 1984 vintage Kraft servos were too slow for the delta in the photo, but this shouldn't be a problem now.

I categorically ignore the 213mph straight-line speed record set in 1971 by Goukoune and Myakinine of the Soviet Union. That record was set under time-measuring rules that were precise to only 10 percent. A disparity of 0.2 second in the timers' clocks was allowed, and the time interval was 2.09 seconds for the 200m course. In addition to this inherent imprecision, the crude timing methods set up by the event director could easily have added another 20 percent error in favor of the pilot ... but that's another story. They didn't cheat; they simply used loopholes to their advantage. Tradition holds that if the competitor's national aeroclub certifies a record, then the FAI will not deny it. So the 213mph record was certified, and then the FAI locked the bam door after the horse had been stolen by imposing super-rigid timing good to 1/100 second for straightaway records! Automated systems and sophisticated equipment far beyond the reach of modelers are now required. As far as I know, no one has figured out how to meet these rules since they were put on the books.