The Dragonfly is a plane designed to break several official FAI world aviation endurance and range records in the F5S category (electric aircraft, 5kg limit). To date the airplane has set world records for duration (continuous time aloft) and distance to goal and return. The endurance record set by the Dragonfly team has been recognized as one of "The Most Memorable Aviation Records of 2006" by the National Aeronautic Association NAA. The Dragonfly gets its name from the resemblance of the fuselage shape to the body of a dragonfly.
Wingspan: 14.5 ft
Aspect Ratio: 20
Fuselage Length: 8 ft
Empty Weight: 3.5 lb
Gross Weight: 11.02 lb
Dr. Andy Arena
Don Lambring (Official FAI observer)
Distance to Goal and Return Mission
To attempt an official point and return mission, the proposed launch/landing point, and the turn-around point must be stated before the flight, and signed by the FAI official. Credit is only given for this distance, and the aircraft must land within a certain distance of the proposed point.
World Record Attempt Friday, June 2, 2006
The morning of June 2nd was chosen for the light wind conditions predicted. The flight was to be primarily a range test at partial fuel, since the range capabilities of the airplane had not been fully demonstrated. The proposed flight path was from just outside of Kildare, OK, toWakita, OK. This path was chosen due to the favorable road conditions, good bridges, and sparse population.
After completing preflight checks and signing all appropriate FAI paperwork with the assistance of the FAI observer, Don Lambring, the team was ready. Launch occurred at approximately 6:14 am, and the aircraft climbed well, and was immediately turned on course. Thomas Hays was the pilot at launch, and Dustin Gamble was the launcher. The lead car was a convertible driven by Dustin Gamble with Thomas Hays and Dan Bierly riding in the back seat taking turns flying the plane. The chase vehicle was driven by Don Lambring with Andy Arena tracking progress with the GPS and checking performance and fuel consumption.
The performance of the airplane was better than predicted, and within 15 minutes of launch, the capabilities of the airplane were known. Landing occurred approximately 3 hours and 45 minutes later in a wheat field across the street from the launch point.
Official Record at time of attempt: 80.43 km (49.97 mi) Jüri LAIDNA (Estonia)
Dragonfly flight on June 2, 2006: 144.42 km (89.74 mi)
Record officially ratified by the FAI January 17, 2007.
The Endurance or Duration mission is continuous time aloft. Takeoff and landing must be within a specified distance of each other. Time starts when the plane becomes airborne, and time stops when the plane touches down.
World Record Attempt Saturday, June 24, 2006
Location: OSU Agricultural Research Station Just north of Perkins, OK at the intersection of hwy 177 and 33.
Weather on the morning of June 24 was perfect, and winds were forecast to be light all day. Takeoff was scheduled for 6:00 am. Since June 24 was near the summer solstice, plenty of daylight was available for the attempt.
The team arrived at the site a little before 5:00 am in the dark, and began pre-flight preparations. The necessary FAI paperwork was also completed with the observer Don Lambring. Due to the moisture in the air from the previous day's rain, there was a heavy dew, and the plane had to be continually dried off. The Dragonfly weighed in at an official 4.959 kg (max allowable is 5) At that point the plane was ready to fly.
Dustin carried the plane to the launch coordinates, and launched the plane to the north over a wheat field at 5:59:09. Thomas was piloting, Don was starting one timer, Dan was marking the GPS time, and Andy was video taping and starting a third timer. The plane climbed slowly and after a few minutes, Thomas leveled the airplane off, and throttled back to cruise power, and the team settled in for a long day.
Not long after launch, a fog formed. The pilots Dan and Thomas flew the plane overhead in order to not loose visibility. The plane at this point was requiring slightly more power than predicted, but this was attributed to the heavy moisture.
As the day progressed, the performance improved a bit, and the ground started heating up which resulted in thermal turbulence. Often times, several birds would be seen circling in the thermals as the Dragonfly was flying. The turbulence however resulted in a high pilot workload. As a result the pilots switched off approximately every 30 minutes to give each other a rest. The rest of the team would read the data coming down from the telemetry system, and make calculations on energy consumption and predicted endurance. The data that was sent included voltage, current, altitude, and g-load.
One of the primary concerns of the team during the flight was the structural load on the plane. The Dragonfly had very little margin for error structurally, since it was designed to be very light in order to maximize fuel weight. This is unlike a typical sailplane that can sustain large g-loads. The wing structure had been tested in the lab to a simulated 2.5 g's without damage. The pilots attempted to keep the loads under this level which was difficult at some times due to the conditions. At one point during the flight, late in the day just before passing the existing record, the plane hit a particularly large "bump" that resulted in the plane experiencing over 2.7 g's. This was the most terrifying part of the flight.
Other than a few "scares" the flight went beautifully, and the plane performed basically as predicted. The pilots did an excellent job managing energy during the flight, and operating the Dragonfly effectively. At approximately 4:37pm the previous record was passed, and all present cheered. Some visitors from Stillwater came to visit the team during this time.
When telemetry indicated that there was little power left, the approach was begun. It was decided that enough energy would be left in the batteries to allow a go-around if needed. The plane landed back in the wheat field close to where it was launched at 6:20:50pm. When the plane was returned to the lab, the remaining energy was drained from the batteries. It was determined that only 9 minutes of cruise power remained in the batteries. 98.8% of the fuel had been consumed.
Official record at time of the attempt: 10h 38mn 30s on June 21, 1998 by Emil HILBER
Dragonfly flight on June 24, 2006: 12h 21mn 40s
Record officially ratified by the FAI January 17, 2007.
Oklahoma State University
Oklahoma NASA Space Grant Consortium