Porsche 914

The 914/8 was not considered for production as a regular model. Some remotely-controlled devices are loosely called robots, but are more properly categorized as teleoperators since they do not operate autonomously, but only under control of a human operator. The chassis remained largely unchanged, although retuned shocks and custom coil springs cut from titanium were added to the package along with the upgraded bodywork, larger wheels and tires and uprated brakes. Radio-controlled teleoperators are used for such purposes as inspections, and special vehicles for disarming of bombs. Wheel arches were flared out, larger wheels were fit, and a cooling aperture for the oil cooler was affixed to the front bumper. Today radio control is used in industry for such devices as overhead cranes and switchyard locomotives. The 914/8 bodywork differed from that of the standard 914 in only a few small but noticeable ways. The most outstanding example of remote radio control of a vehicle are the Mars Exploration Rovers such as Sojourner.

The third was sold to a dentist in Maryland, and a relative inherited the car thereafter, but crashed the car and sold it to a mechanic. Instead of a "turn left" signal that is applied until the aircraft is flying in the right direction, the system sends a single instruction that says "fly to this point". The second, a red unit powered by the full-blown, 400 horsepower (298 kW) 908 motor was presented to Ferdinand Piech, Ferry's son-in-law and then chairman of the Volkswagen group. Remote control military applications are typically not radio control in the direct sense, directly operating flight control surfaces and propulsion power settings, but instead take the form of instructions sent to a completely autonomous, computerized automatic pilot. The first, a silver unit, was built to comemorate "Ferry" Porsche's 60th birthday, and was powered by a carburated and de-tuned 908 race motor making 260 hp (194 kW). Advantages include bit error checking capabilities of the data stream (good for signal integrity checking) and fail-safe options including motor (if the model has a motor) throttle down and similar automatic actions based on signal loss. Two prototype 914s, dubbed 914/8, were built during 1969. More recently, high-end hobby systems using "Digital Proportional" features have come on the market that provide a computerized digital bit-stream signal to the receiving device, instead of analog type pulse modulation.

These can be easily recognized by their flared fenders and more aggressive front ends when compared to the 914. The relative simplicity of this system allows receivers to be small and light, and has been widely used since the early 1970s. A supercar version known as the Porsche 916 was planned for production in the mid-70's, but was cancelled after the production of approximately 16 prototypes. The pulse trains representing the whole set of channels is easily decoded into separate channels at the receiver using very simple circuits such as a Johnson counter. The 914 was Motor Trend's Import Car of the Year for 1970. The latter produces a voltage proportional to the output position which is then compared with the position commanded by the input pulse and the motor is driven until a match is obtained. The 2.0 litre Type IV contuinued to be used in the 912E, which provided an entry-level model until the 924 could be delivered. An electric motor and reduction gearbox is used to drive the output arm and a variable resistor or "potentiometer".

914 production ended in 1975 (though some leftover 1975 models were sold as 1976 models), two years prior to the introduction of its eventual replacement, the 924. Off-the-shelf servos respond directly to pulse trains of this type using integrated decoder circuits, and in response they actuate a rotating arm or lever on the top of the servo. bound units to help with emissions control. The pulse is repeated in a frame of between 14 and 20 milliseconds in length. For 1974, the 1.7 was bored out to 1.8 litres, and the new Bosch fuel injection system from the 2.0 was added to U.S. In the type of system most commonly used today PWM is used, where transmitter controls change the width (duration) of the pulse for that channel between 920 µs and 2120 µs, 1520 µs being the center (neutral) position. Slow sales and rising costs prompted Porsche to discontinue the 914/6 variant in 1972 after producing only a little over 3,000 of them; its place in the lineup was filled by a variant powered by a new 2.0 litre, fuel injected version of VW's Type IV 4-cylinder engine in 1973. These R/C systems made 'proportional control' possible, where the position of the control surface in the model is proportional to the position of the control stick on the transmitter.

Many enthusiasts regard this as having been a big mistake on Porsche's part. Typical radio control systems for radio-controlled models employ pulse width modulation (PWM) or pulse position modulation (PPM), and actuate the various control surfaces using servomechanisms. Porsche handled export to the U.S., where both versions were badged and sold as Porsches. While early control systems might have two or three channels using amplitude modulation, modern systems include 20 or more using frequency modulation. 914/6 models used the same suspension and brakes as the 911, giving the car handling and braking superiority over the 4-cylinder VW models in addition to higher power output. The mechanical resonant systems using reed relays were replaced by similar electronic ones, and the continual miniaturization of electronics allowed more signals, referred to as control channels, to be packed into the same package. Karmann manufactured the rolling chassis at their own plant, then either sent them to Porsche for fitment of the Porsche suspension and flat-six engine or kept them in house for VW hardware. These systems were widely used until the 1960s, when the increasing use of solid state systems greatly simplified radio control.

Porsche's 914/6 variant came with a carburetted 2.0 litre 110hp flat six-cylinder engine, taken from the 1969 911T. These were typical on/off signals. Volkswagen versions originally came with an 80hp fuel-injected 1.7 litre flat-4 engine based on the unit that powered the VW 411 and 412 saloon cars (the VW Type 4). The controller's radiotransmitter would play the different frequencies in response to the movements of a control stick. Although this had an effect on sales, people soon realized that the 914/6, which shared the 911T's powerplant but was lighter weight and better balanced, was actually a quite competent sports car, and the car became Porsche's top seller during its entire model run, outselling the 911 by a wide margin, with over 118,000 units sold worldwide. The vibration would push on electrical contacts connected to the actuators of the control surfaces of the missile. As a result, the price of the chassis went up considerably, and the 914/6 ended up costing only a bit less than the 911T, Porsche's next lowest price car. In front of the speaker were a number of small metal "fingers" with different resonant frequencies, each one tuned to vibrate when a particular tone was played in the speaker (a so called reed relay).

Unfortunately for Porsche, complications arose after the death of Volkswagen's chairman, forcing the deal to be re-worked. A small radio receiver was placed in the missile, the signal from the controller (transmitter) was "played" into a small speaker. market, and convinced VW to allow them to sell both versions as Porsches in North America. Radio control systems of this era were generally mechanical in nature. Although they stuck with this setup in Europe, Porsche decided during development that having VW and Porsche models sharing the same body would be risky for business in the U.S. However none of these systems proved usable in practice, and the one major US effort, Project Aphrodite, proved to be far more dangerous to its users than to the target. As a cost saving measure, and in part because VW wanted engineering help from Porsche, the two decided to share a platform, originally intending to sell the vehicle in four-cylinder trim as a Volkswagen and in six-cylinder trim as a Porsche. Both the British and US also developed radio control systems for similar tasks, in order to avoid the huge anti-aircraft batteries set up around German targets.

By the late 1960s, both VW and Porsche were in need of new models; Porsche was looking for a model to replace the 912 and VW was looking to add a sporty, inexpensive 2-door to the lineup. The German development teams then turned to wire guidance once they realized what was going on, but these systems were not ready for deployment until the war had already moved to France. The Porsche 914 was a sports car automobile built and sold collaboratively by Volkswagen and Porsche from 1969 through 1975. Jammers were then installed on British ships, and the weapons basically "stopped working". After initial overwhelming successes, the British launched a number of commando raids to collect the missile radio sets. The effectiveness of the Luftwaffe systems was greatly reduced by British efforts to jam their radio signals.

However by the end of the war the Luftwaffe was having similar problems attacking allied bombers, and developed a number of radio-controlled anti-aircraft missiles, none of which saw service. Their main effort was the development of radio-controlled missiles and glide bombs for use against shipping, a target that is otherwise both difficult and dangerous to attack. Radio control was further developed during World War II, primarily by the Germans who used it in a number of missile projects. Nikola Tesla patented a radio-control scheme as early as 1899, and various radio-controlled ships were used for naval artillery target practice by the 1920s.

The possibility of radio remote control was appreciated almost as soon as the first demonstrations of radio itself; the credit for the first to suggest radio control of aircraft may belong to Patrick Young Alexander as early as 1888. . The term is used frequently to refer to the control of model cars, boats, airplanes, and helicopters from a user-held control box (radio.) Industrial, military and scientific research all make use of radio-controlled vehicles as well. Radio control is the use of radio signals to remotely control another device.