Welcome to Droning On, Hackaday’s new column covering all things unmanned. In this column we will primarily focus on aerial vehicles, both fixed and rotary wing. Expect to see traditional R/C, as well as First Person View (FPV) models, computer controlled autopilot systems, as well as anything new that shows up on our radar.
First, a little bit of history. The earliest radio control vehicle in history was designed by a man known well to Hackaday, Nikola Tesla. Tesla presented a radio controlled boat at an electrical exhibition in New York in 1898. Tesla called the system “Teleautomaton” and said the craft utilized a borrowed mind. In addition to cruising around a man made pond, the boat could solve equations by blinking lights atop two of its masts. Tesla would encourage viewers to call out math equations, then flash the lights from the boat’s control panel.
For many years R/C as well as its cousins Free Flight and control line were hobbies occupied solely by hackers. One needed to have metal machining skills to build engine parts, draftsman skills to read plans, and carpentry skills to build airframes. Radios were built from tubes. Control, if it may be called such, was all or nothing – so-called “bang-bang” systems. Much like their model railroad compatriots, R/C plane modelers built with the parts they had on hand. Several early DIY R/C planes were controlled by rotary telephone dials. Dial 1 to pull up, 2 to turn left, etc. Control surfaces were moved by rubber powered escapements rather than the servos we’ve come to know and love. Aerodynamics also came into play. With such rudimentary control systems, planes were designed to be inherently stable. Thankfully there were numerous proven air frame designs available from the free flight arena. Slow flight, high dihedral, and docile stall behavior were the rule of the day. Early R/C planes could be thought of as free flight vehicles with occasional suggestions via radio control. Click past the break to find out more about drone history, and to read about the recent FAA judgement.
The burgeoning R/C industry gave rise to military drones. The Radioplane OQ-2 was designed by actor/Hobby Shop owner Reginald Denny. The OQ-2 saw operation as a target drone, often used to improve the targeting skills of Navy gunners. Models that survived target practice were landed via parachute. The OQ-2 and its derivatives were produced in the thousands in the World War 2 era. In the height of the OQ-2’s popularity, Yank magazine ordered a photo shoot in the factory. Norma Jeane Dougherty, one of the OQ-2 Factory workers, was selected to pose with partially assembled OQ-2s for the shoot. The resulting photo helped launched her career as Marilyn Monroe.
As time went on helicopters also saw use as drones. The Gyrodyne QH-50 DASH was a contra-rotating rotary wing craft flown from WWII era Navy Destroyers. The QH-50 first flew in 1959, with a mission of finding and attacking Russian submarines. Interestingly, the DASH used rotor tip vanes to achieve yaw control, as the rotor blades were directly linked in via the turboshaft engine gearbox. 755 DASH systems were built. When shipboard service ended, they were used to tow aerial targets at White Sands and China Lake until their retirement in 2006.
The last 15 years or so has seen an explosion of smaller drones, often categorized as “Small Unmanned Aerial Systems” (sUAS). This category covers military, commercial, and personal drones, as well as R/C systems. The increase in prevalence can be traced to several technologies improving. Thanks to MEMS technology, gyroscopes and accelerometers are now chip scale. In the past, precision gyros were large, heavy systems. Even Radio Control helicopter gyros were 1.5” square boxes containing a power-hungry motor and a spinning brass wight. Lithium batteries, both Li-Ion and LiPo have increased power density and maximum current over their Nickle-Cadmium (NiCAD) and Nickle Metal Hydride (NiMH) counterparts. Electric motors have advanced from the brushed motors of the past to efficient brushless motors. The move from inrunner to outrunner motors has eliminated the need for power robbing gearboxes. Frequency hopping 2.4Ghz Radios have had a huge impact on the R/C side of things. Older 72MHz radios operated on single frequencies. If two radios were transmitting on the same frequency, a flying aircraft would not be able to discern which one was from its transmitter, leading to “shoot downs” and crashes.
But it’s not all clear skies and calm winds in drone land. Media coverage often equates small drones operated by private citizens with large military drones. Public privacy concerns abound. In the USA, a long brewing fight over drone flight has come to a head.
Historically, the Federal Aviation Administration has maintained control for full scale aircraft in the United States. The semi-official governing body of model aircraft has been The Academy of Model Aeronautics (AMA). The AMA has existed since 1936 as a voluntary organization. In June of 1981, the FAA issued an advisory on the operation of model aircraft (PDF link). The AMA expanded upon these rules in their official safety code (PDF link).
With respect to full scale aircraft, the primary takeaways from these rules are:
- Fly below 400 feet above ground level (AGL)
- Do not fly within 3 miles of a full scale airport without permission of the airport operator.
- Yield to human carrying aircraft.
While 2 and 3 are common sense, rule 1 has always been disregarded and treated with disdain. YouTube is filled with videos of planes, helicopters, and multicopters over 400 feet. Travel to any AMA field on any given Sunday, and you’ll find models flying above 400 feet.
This was the state of affairs until the early 2000’s, when aerial photography became popular in the model aircraft crowd. As systems improved, modelers began performing for-pay photo shoots. In 2007, the FAA issued a notice effectively banning commercial flight of small unmanned aerial systems. While private use is still legal, An entire industry sits waiting for the governing body to set some regulations in place. This is a situation near and dear to my heart. I last wrote about it 3 years ago in my own blog. Between 2005 and 2013, federal foot-dragging was the name of the game. Some commercial R/C photography companies sprang up, many using the “loophole” that they were flying their R/C planes with cameras for fun, and only selling the pictures for profit. Several of these operators have received informal calls as well as formal cease and desist letters from the FAA.
Things came to a head with a 2011 commercial flight made at the University of Virgnia by Raphel Pirker, aka Trappy of Team Black Sheep. Trappy is a Swiss citizen living abroad. His plane is a 56” Styrofoam flying wing, which he often flies via First Person Video (FPV). In the past he’s made incredible non-commercial flights. One example has Trappy flying near several famous New York City bridges as well as The Statue of Liberty. Videos like this put Trappy squarely in the cross-hairs of the FAA. They decided to act with a $10,000 fine on the UVA video. Trappy appealed the issue to a court case, which was decided by Judge Patrick G. Geraghty on March 6, 2014 (PDF link). Jude Geraghty’s threw out Trappy’s fine. He further ruled that the restrictions put into place by the 2007 FAA notice were not enforceable, as they were simply policy notices, not created as part of the formal rule-making process. At first blush it would seem that the skies over the USA have been opened. However, the FAA has appealed the ruling to the National Transportation Saftey Board. According to the FAA press release, this keeps Jude Geraghty’s decision from taking effect until the NTSB makes a decision. The FAA has also issued a news statement “Busting Myths” about Unmanned aircraft. Consider the source, and take this one as you may.
That about wraps it up for the first edition of Droning On!
[Images from Wikimedia Commons]