Killinger & Freund Motorcycles

From the German MOTORRAD magazine, October 1938 (Translation: Hartmut Schouwer):

In Italy five aero engineers once built the RONDINE. Now it’s called GILERA and is destined to win a lot of races for the GILERA brand. When technicians do something with love, something good will turn out.

Three years ago five technicians from Munich started to design another nonconformistic motorcycle, but they had another target: they created a modern bike with front-wheel-drive and and aerodynamic, rational shape. That means a bike for daily use. And now it’s ready for the show.

Our readers will remember the MEGOLA story. The magazine staff had restored an old MEGOLA to recollect the merits of this multiple-cylinder front-wheel-drive bike. We wrote: “Fantastic behaviour in curves . . . a child could ride it on sand . . .”

What the five technicians from Munich – the names of the designers/engineers are KILLINGER and FREUND – now completed is more than an improved MEGOLA. The engine displacement is again 600cc and it is also incredibly light: 135 Kilogr. (with fuel), but this bike has a three-cylinder two-stroke engine in the front wheel, it HAS a transmission and a clutch, it has a comfortable front and rear suspension and looks elegant and thrilling.

There’s always a crowd of people around the displayed bike indicating that there’s happening something great. If you join them and listen to them you will be astonished that most of them like the shape of this bike. That’s important because the technicians wanted to build a bike that can be sold in large numbers some day. The people are used to aorodynamic shapes of car bodies now and it seems that they already expectedsomething like that. The shape was developed to meet all these requirements: all moving parts covered, dirt protection, multicylinder and front-wheel-drive. Another target was to reduce the numbers of different parts. This bike has less parts than a light 100cc-bike!

At first sight you realize the dirt-protective and aerodynamic covers of the front and rear wheel. Frame, fork and fuel tank are also aerodynamically improved. We were impressed by the nice details and good shaped transitions of the different body parts, as seen on race bikes.

And now the construction: the middle of the frame and the rear wheel cover are currently built as sheetmetal shells around a tube frame. For the mass-production version there are plans to build the middle frame as a boxed frame, welded together from two pressed sheetmetal parts. Of course this supermachine has a rear suspension. It is linked to the lower end of the (inner) tube frame and fixed with flexible (rubber/metal???) elements which don’t need any service. A lid in the box frame allows access to the seat springs to regulate the hardness of the seat’s suspension.

The steering is like that of a normal bike, but the telescopic elements (80 mm lift) are more vertical than usual. That means that the wheelbase won’t change much when the front fork dives in.

The front-wheel-drive is much better than the Megola design. First, the weight of the engine (unsuspended mass) is lower. The front wheel with engine has a weight of 50 Kilos. Second, a custom carb without a float needle doesn’t have problems that could be caused by vibrations. And third, the light-weight battery ignition allows to start the engine without problems and helps to keep the engine weight low. The distributor and the points are located in the hub. The technicians originally intended to build a dynastarter. These improvements (plus transmission and clutch) had been impossible to add to the MEGOLA design.

The three-cylinder two-stroke engine uses a Drehschieber (= turning disk with a hole for more exact timing of the intake of the fuel-air mixture). The fresh fuel-air mixture is sucked in by the vacuum in the three crankshaft housings as usual. The Drehschieber does the intake timing for all three cylinders. The engine is not a radial engine as known from planes. And there is no need for a flywheel. All three cranks seem to work on one common gear. This arrangement and the recoil of the pistons in the turning direction should secure a perfect balance of the moving parts. The cylinders are made of KS (brand name) iron cylinder walls and are totally embedded in the Silumin (kind of alloy) engine housing. Alloy cylinderheads with lots of cooling fins and the exhaust pipes are the only things that can be identified as engine parts between the spokes of the cast alloy wheel. These flat spokes are designed to serve as a cooling fan. The two-speed transmission is built as a differential transmission and uses slope-meshed gears. The clutch is made of usual clutch disks. The clutch (with the springs at the outer circle) is located in front of the transmission. The transmission is actuated by steel cables (foot-operated). All parts of the engine allow easy access for service work. After the removal of the engine – only two bolts and some wiring have to be removed – all important parts are within reach. The tire can also be removed easily. You have to unlock a safety mechanism and can remove the tire completely with the split rim. The front brake is installed in the hub. The rear suspension also has telescopic oil-filled shock absorbers. The gasoline runs down through flexible hoses.

Five men worked for three years on this machine. The bike was test-driven already and the engine was tested on a test-stand. As there are so many progressive ideas built into this bike, we hope that the developers will have a chance to complete their work, because we would like to experience the preferences of this bike some day:

Better handling – more safety – less weight – simple construction – no chain or cardan shaft – no valves – tangential arrangement of the cylinders for smooth engine characteristics.

Ch. Christophe

Killinger & Freund Front Wheel Drive Motorcycle

Many thanks to the person who sent the image above, which I believe to be the one published in Motorrad. Ed. That is the whole engine with transmission and clutch in the front wheel. You can see the three tangentionally arranged cylinders and the cylinderheads outside the engine housing. The removal of the front wheel is just as easy as the removal of the rear wheel on a normal bike. The most interesting detail is the split rim, like those designed by Josef Stelaer for the BMW six-days competition bikes. This allows to remove the tire after unbolting some nuts and avoids the usage of a special two-ended air tube like in the MEGOLA (a “normal” endless tube could be used).

October 25, 2002
I located the Killinger & Freund page and found the following.
The following 10 statements are from this Killinger & Freund page..

#1..."this bike has a three-cylinder two-stroke engine in the front wheel"
#2..."This bike has less parts than a light 100cc-bike.
#3..."The technicians originally intended to build a dynastarter"
#4..."The three-cylinder two-stroke engine uses a Drehschieber (=turning disk with intake holes)"
#5..."mixture is sucked in by the vacuum in the three crankshaft housings"
#6..."The engine is not a radial engine"
#7..."All three cranks seem to work on one common gear."
#8..."the recoil of the pistons in the turning direction"
#9..."– no valves –"
#10..."the three tangentionally arranged cylinders and the cylinderheads outside the engine housing."

My comments on the 10 items follow.

#1...this bike has a three-cylinder two-stroke engine in the front wheel.
""not So.""
"this bike has THREE ONE CYLINDER, TWO STROKE ENGINES with seperate crankcases & crankshafts tangentially mounted on a 4th central housing and radially geared to a common internal fly wheel, clutch and 2 speed transmission."

#2..."This bike has less parts than a light 100cc-bike.
"" not so "" If referring to the power plant only and not to the chassis parts, including the spokes, screws and nuts.

#3..."The technicians originally intended to build a dynastarter"
""good intention""

#4..."The engine uses a Drehschieber (= turning disk with intake holes)" "a rotary disc valve"
""correct"" But this contradicts item #9 -no-valves-

#5..."mixture is sucked in by the vacuum in the three crankshaft housings"
""correct"" but three crank cases dictate three engines. As well as three intake valves and crankshafts. Contradicted by item #9 that states -no-valves-

#6..."The engine is not a radial engine"
""correct"" but it is round (-;¶

#7..."All three cranks seem to work on one common gear.".
""correct"" this 'common gear' being the equivalent to the 'ring gear' on a conventional 'flywheel'.

#8..."the recoil of the pistons are in the turning direction"
""correct""

#9..."– no valves –"
""not so""

#10..."the three tangentionally arranged cylinders and the cylinder heads are outside of the engine housing."
""correct""

Items #2 thru #5 contradict the statement made in Item #1.

#2 & #4 "three crankshaft housings" = Three crankcases. & Three crankshafts. Or Three Engines.

Killinger & Freund Motorcycle

It is a very interesting concept. I see no reason why this would not function. I do see a very serious potential problem that would, in my estimation, cause early mechanical failure of the 3 engine(s) crankshaft gears mating to the flywheels ring gear.

A reciprocating engine has hi energy rotational, cyclic oscillations (radial power and inertial vibrations) that are damped out by the flywheels mass. If these vibrations and masses are not coupled directly, and are seperated by the gear clearance in this design, the gears will very likely wear out very rapidly,

I made a little free-hand sketch of what this power plant would approximately look like.

The piston travel is "Tangential" to the circumference of the flywheel.

And all other items mentioned are complied with, except the "Drehschieber" the rotary disc valve plate.

There are several methods of incorporating the Drehschieber in the sketch, but the sketch was getting crowded..

Regards,
Ralph-1 at webtv.net

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