B 84

My new 4-stroke flat-four is now ready for take of!

Video B 84

After a period of development of at least 1 1/2 years I’m now able to offer you a four cylinder flat with 84 ccm - equivalent to the 500 cu-inch-class – and I must admit that I’m a little bit proud on this engine..:
The basic construction elements of pistons and arbour-bearing-sleeves have been adopted from the approved V42-engine in a modified manor of construction: Like a “big” engine, the pistons are equipped with piston-- and oil-scraper-rings.
Comparing with the structure of some more inexpensive engines available on the market, the B84 is also equipped with a solid, one-piec, precised hardened crankshaft with stable connecting rods and bushings . It is placed in a solidly built, torsion-resistant crankcase, kept in its place by nearly indestructible bearings:
Vibrations and pre-programmed “weak-points” are minimized by this way.
Watching the photos, you surely have recognized, that the B84 has no single cylinder-heads as the V42, but “ benches” for each pair of cylinders: This is not a personal design fashion of mine, but a constructive necessity with decisive advantages:
The lavish constructed “ double-heads” prevent an overheating of the rear cylinders, that might appear while running the engine under unfavourable operating conditions; the energy can be acceded by the colder front cylinders, to avoid this constructive-related problem - comparable to the solutions of Volkswagen and Porsche with air-cooled flat-engines. –
Of course the B84 – similar to the V42 - has its own independent lubrication-system, that allows a running with unleaded gas without any necessary oil additives! The only thing to do, is to control the oil level in the crank case from time to time – as you usually do it with the engine of your car. -
Now, of course, there’s the decisive and important question:
Is the B84 suitable for aerobatics?
I can answer this question with a clear “Yes” – without any limits:
The “heart” of the lubrication system is a cog-wheel-pump, that – in contrast to a conventional piston-oil-pump - is able to build up a reliable and constant oil pressure over the whole range of rpm – a decisive advantage in practical use. –
By this way, a pump-fed-lubrication with a sufficient number of oil-tubes, that are placed in- and outside the motor-block, guaranties a reliable lubrication of all necessary engine-parts - independent from the flight position of the engine while flying stunt figures. –
For friends of practical use: The single carburettor guaranties an easy and quick engine-setting with a reliable performance through the whole range of rpm. –
The B84 is easy to start: A Becker-MC-Ignition-system with integrated automatic ignition advance enables a “fingerfriendly” and spontaneous (cold or warm ) engine start ; the ignition advance system harmonizes with the characteristic of the B84: High torque is available from low engine speed up to maximum of rpm: Good news for friends of “big props”!
This engines convinces its owner with its smooth running combined with a powerful, fine and decent scale sound reminding to large airplane-engines!
The power of this engine I can describe with a few words: For starting and flying my Fly-Baby biplane with a weight of 12 kilograms I have to be cautious with the gas-stick; the B84 is never really seriously stressed…
The included engine-bearer is specially designed for this engine and enables a precise, secure and simple assembly at the most of fuselage-motor-frames.-

Technical Data:

Size: 84 ccm or 504 cu inch
Bore: 32,00 mm
Stroke: 26,00 mm
Weight: 3100 g
Gas: gas unleaded
Ignition: System Becker-MC with ignition advance
Output: 5800 rpm with 26“X12 prop.

Engine B84, including ignition-system and engine bearer: 2680,00 €