Coincidentally, that would be the same position where the prop comes up against
compression for propping it just as you start on the down stroke with the
blade. TDC would be horizontal with an impulse coupled magneto firing roughly
5 - 10 degrees past horizontal (or TDC). The nose of a KR is so low that they
can sometimes be difficult to hand prop with the prop indexed with #1, but on
most aircraft, it is a perfect fit.
-Jeff
-- "Serge VIDAL" <serge.vi...@sagem.com> wrote:
That's all fine, except if you don't have a starter motor, in which case
you have to set your prop to "kick" right when you swing the prop. I found
that to be fairly critical, but I have no clue which angle is best. When I
changed my engine from a 2.0 liter VW to a 2.4 liter VW, I replicated the
same offset angle between the prop and the crank (whatever that was, can't
remember), only to find that it would not work well. So, I proceeded by
trial and error (rotate one bolt left, then two bolts right) and chose the
position that seemed to work best.
Oddly enough, I found out that for a difficult start (hot engine,
typically) there is only one camshaft position that will work fine. That
is, one blade and not the other, and then, only every second turn.
Go figure...
Serge Vidal
KR2 ZS-WEC
Paris, France
"Jeff Scott" <jscott.pi...@juno.com>
Envoyé par : krnet-boun...@mylist.net
2005-01-03 18:14
Veuillez répondre à KRnet
Remis le : 2005-01-03 18:16
Pour : kr...@mylist.net
cc : (ccc : Serge VIDAL/DNSA/SAGEM)
Objet : Re: KR> KR annual
That is actually the correct indexing of a two blade prop for either a 4
or 6 cyl engine. It places the propellor in the same rotational plane as
the crank on #1 cyl, which would also be in the same rotational plane as
the last cyl, whether it is #4 on a 4 cyl or #6 on a 6 cyl, in other
words, the front and back of the crank. On a 4 cyl, the prop is then in
the same rotational plane as all 4 crank throws. I have used that
technique to fix prop vibration problems on 4 and 6 cyl engines with both
wood and metal props.
Usually, the prop balance and tracking are not quite perfect and the same
is true for the engine. Once the prop is indexed correctly, changing the
prop 180 degrees can also make a difference in vibration. Once you find
the position the prop runs smoothest on that particular engine, mark it
and always re-install with the same indexing.
-Jeff
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