Killinger and Freund Motorcycle - AbsoluteAstronomy.com

The Killinger and Freund Motorcycle was an attempt in 1935 by a group of five German engineers from Munich

Munich

Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...

to design a more streamlined and modified version of the German Megola

Megola

The Megola was a German motorcycle produced between 1921 and 1925 in Munich. Like Bimota, the name is a portmanteau derived loosely from the names of its designers Meixner, Cockerell, and Landgraf.-An Unusual Design:...

front-wheel drive motorcycle. The work took three years to complete but the result was impressive. The engine displacement stayed the same as the Megola at 600 cc but was much lighter and more simplified than a standard 100 cc motorcycle

Motorcycle

A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

of the time.

Design

The motorcycle featured a three cylinder two-stroke engine built right into the front wheel, transmission and clutch, with more comfortable front and rear suspension.
Streamlining was important as aerodynamics was the first priority of the team who wanted all the moving parts covered, dirt and mud protection, and an elegant style. Other priorities were that the motorcycle be multi-cylinder and possess front- wheel-drive. Their design met with success.

Aerodynamics and steering

The first impressions of the new motorcycle was of a streamlined racing machine with rounded covers for the front and rear wheels, aerodynamically improved fork, frame, and fuel tank all built on a tubular framework covered in sheet metal.

The rear suspension was linked to the lower end of the tubular frame and featured flexible rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

and metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

elements that did not require servicing. Steering was much like an ordinary motorcycle but with more vertical telescopic elements than usual, which translated into a wheelbase that wouldn’t change much whenever the front fork dived.

Front wheel drive, carburetor, and ignition

The new front-wheel-drive was a vast improvement over the old Megola design. The weight of the engine was lower. The front wheel with integrated engine

Engine

An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

had a combined weight of 50 kg (110 lb). Additionally, a custom carburetor without a float needle didn’t have the problems caused by vibration. And finally, the light-weight battery

Battery (electricity)

An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

ignition allowed trouble-free engine starts and helped to keep the engine weight low. The distributor

Distributor

A distributor is a device in the ignition system of an internal combustion engine that routes high voltage from the ignition coil to the spark plugs in the correct firing order. The first reliable battery operated ignition was developed by Dayton Engineering Laboratories Co. and introduced in the...

and the points were located in the hub. The technicians originally intended to build a dynastarter. These improvements would have been impossible to add to the old Megola design.

Engine, timing, clutch, and transmission

The three cylinder two-stroke engine used a Drehschieber ("rotary valve", a turning disk, with intake holes for exact timing of the fuel-air mixture intake). The fuel-air mixture was sucked in by the vacuum in the three crankshaft

Crankshaft

The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

housings as usual. The Drehschieber does the intake timing for all three cylinders. The engine was not a radial engine

Radial engine

The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...

associated with aircraft

Aircraft

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

and there is no need for a flywheel. All three cranks worked on one common gear

Gear

A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....

. This arrangement and the recoil of the piston

Piston

A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...

s in the turning direction secured a perfect balance of the moving parts. The cylinders were made of KS (Kolbenschmidt) iron cylinder

Cylinder (engine)

A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

walls and were embedded in the Silumin alloy engine housing. The only things that could be visibly identified as engine parts were the alloy cylinder heads with multiple cooling fins and the exhaust pipes located between the spokes of the cast alloy front wheel

Wheel

A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...

. These flat spokes were designed to serve as a functional cooling fan. The two-speed transmission

Transmission (mechanics)

A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...

was built as a differential transmission and used slope-meshed gears. The clutch

Clutch

A clutch is a mechanical device which provides for the transmission of power from one component to another...

was made of conventional clutch disks. The clutch (with the springs at the outer circle) was located in front of the transmission. The transmission was actuated by foot-operated steel cables. All parts of the engine allowed easy access for service work. After the removal of the engine – only two bolts and some wiring had to be removed – all important parts were within reach.

Tires, shock absorbers, fuel, and seat adjustment

The tire could also be removed easily. You had to unlock a safety mechanism and then remove the tire completely with the split rim (very similar to the split rim developed by BMW

BMW

Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...

). The front brake was installed in the hub. The rear suspension also had telescopic oil-filled shock absorbers. The gasoline

Gasoline

Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

flowed down through flexible hoses. A panel in the frame allowed easy access to the seat springs to adjust the hardness of the seat’s suspension.

Operational history

The Killinger and Freund Motorrad (motorcycle) was test-driven after the engine was tested on a test stand. Its total weight was 135 kg (297 lb).

This design was intended for civilian production but the start of World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

cancelled those plans. One motorcycle was discovered by the US Army in the spring of 1945 at a German military installation but it is not known if this was the original prototype

Prototype

A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...

or another Killinger und Freund Motorrad. The disposition of that captured vehicle is not known.

Today

Rokon

Rokon motorcycle

Rokon is a Rochester, New Hampshire-based motorcycle manufacturer that builds unusual 2-wheel-drive off-road motorcycles which are sometimes referred to as Moto-tractors.-History:...

builds two wheel drive motorcycles, but without a motor in the front wheel.

External links

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