Hi Wx BY
Look at _http://www.hirth-motoren.de/de/motor-3002.html_ and
_http://www.hirth-motoren.de/de/motor-3003.html_
Technical data
(Specifications subject to change without prior notice)
Type: Four cylinder two stroke (boxer)
Displacement: 1042 cm3 (63,6 cu in)
Stroke: 64 mm (2,52 in)
Bore: 72 mm (2,83 in)
Max. performance: 68 kW (92 HP) at 6500 rpm (V)
According to DIN 70020 75 kW (102 HP) at 6500 rpm (E)
Max. torque: 101 Nm at 6300 rpm (V)
116 Nm at 5500 rpm (E)
Carburation: Carburetor (V) or
Multi point injection (E)
Ignition System: Digital mapped CDI
Generator power: 250W, 12V
Cooling: Fan cooling
Weight: 42 kg
Starting device: Electric starter
Running direction: Counter-clockwise, view to
output shaft
Fuel mixture : Mixture 1:50, 2-stroke-oil, fuel
min. 95 octane (RON)
Mixture 1:80-100 with BLUEMAX
2-stroke-oil, fuel min. 95 octane
Why to invent the similar new?
regards, Fritz Schwarz
11.06.2011 20:48, wrote jtw...@aol.com:
>
> In this note we're gonna discuss an (almost) antique engine: the venerable
> ol' McCulloch 4318, more commonly thought of as the Mac 72 - - 72/90
> horsepower @ about 6,000 RPM, 72 cubic inches displacement, 72 pounds [devoid
> of all/any accessories] . . . . . . . . Four cylinder, horizontally opposed,
> air cooled like classic VW 'boxer' engines.
>
>
>
> A loooong time ago these engines were designed, manufactured and used for one
> activity ONLY - - McCulloch sold 'em to go on the firewalls of gunnery-target
> drones and were intended to be flown only once and even then only very
> briefly.
>
> Ha! Having been through Naval Aviation gunnery training as a NavCad student
> pilot myself, and having watched a lot of ground/sea-to-air gunnery training
> among all the branches of military, it was a rare machine that was actually
> blown out of the sky on its first meager tank of fuel! The classic phrase of
> 'shitty shots' comes to mind -- yours truly included! Anyway . . . . . . . .
> .
>
>
>
> The engines had a few . . . . well, 'idiosyncrasies' . . . . to say the
> least. Two cycle/two stroke fuel/air mixture - - 50 parts avgas to one part
> oil, caused plug-fouling quite soon. Single mag ignition. Really weird
> ignition firing sequence: front two cylinders fired simultaneously, then aft
> two cylinders fired simultaneously - - I have never read or heard an
> explanation for this oddity, but HAVE read& heard that the lil four-bangers
> vibrated so badly that within just a few minutes the bushing/bearing areas on
> the carb butterfly valve would literally disintegrate.
>
> Probably the worst aspect of the engines was the absence of or very poor
> quality of all bearings&/or journals used throughout the engine! About forty
> (40) hours was the max I have heard was the most hours one ever obtained on
> an otherwise un-modified engine!
>
> However. With only minor machine-shop work and the installation of decent
> bearings& journals, and the re-timing the ignition (of course) TBOs of up to
> almost 400 hours were not uncommon. Many of the surplus engines were
> modified and ended up on gyrocopters and more than a few homebuilt fixed wing
> flying machines.
>
>
> I have heard a rumour -- from several very diverse sources -- that there was
> a retired machine-shop owner somewhere in Kansas who was also an
> experimental/homebuilder of aircraft. Supposedly, he took two of the Mac 72
> engines and reworked them to an extreme extent: ball bearings were installed
> at both ends of the crankshaft, needle bearings were used on the rest of the
> crank support as well as both ends of the connecting rods! Dual ignition was
> installed and precisely timed. Injector-type carbs (two) and tuned dual
> intake manifolds and tuned exhaust manifolds were also used. Etc., etc.,
> etc. According to the sea-stories/fairy tales, he got over two thousand
> hours total time on the two engines and upon tear-down and precision
> inspection he found absolutely NO appreciable wear . . . . . . . just a
> rumour, though . . . . . . .
>
> [Ya know the difference between a sea-story and a fairy tale? Well, a fairy
> tale starts out, "Once upon a time . . . . . . . " A sea-story usually
> starts out with the adamant phrase, "Now, this is NO shit! . . . . . . . "]
>
>
>
> OK, we're finally at the crux of this missile: There are several thousand
> homebuilt, experimental flying machines, all over the world. AND there are
> darned near that many engine variations! Most are outlandishly expensive,
> most are of questionable reliability, most are one-of-a-kind, etc. etc. etc.
>
> How many readers would be interested in a revival of a ('modernized')
> up-dated Mac 72-type engine???
>
> Let me know, please. We're getting ready to contact the myriad folks who
> hold title to the old Mac drone engines.
>
> WxBY
> ORL/MCO
>
>
>
>
>
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