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Old May 17th 07, 03:25 PM posted to rec.aviation.piloting
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Default Proping Question

On May 16, 8:26 pm, Dana M. Hague
d(dash)m(dash)hague(at)comcast(dot)net wrote:
On Tue, 15 May 2007 17:47:01 -0400, "Morgans"

wrote:
Why no hand propping a nose dragger for you?


I've done it a few times but found it very awkward, as the prop on,
say, a C-150 or 172 is much lower than the prop on a taildragger like
my T-Craft.

On the T-Craft turning it backwards was the standard way of clearing
it if it was flooded... but there was no impulse coupling nor vacuum
pump.


I haven't yet seen a Continental or Lycoming lightplane engine
without an impulse coupling on at least one mag. That impulse
mechanism is necessary for starting because it snaps the mag over fast
so it'll generate a spark, but it also retards the spark to at or near
top dead center so that the engine doesn't kick back. The usual firing
position on an A-65 is 30 degrees before top dead center. The other,
non-impulse mag won't fire at hand-propping speeds, but will sometimes
fire immediately after the engine catches and will stop it or kick it
backwards or make it hammer frightfully until the RPM comes up to
idle. Some pilots will set the mag switch to the impulse mag only
while hand-propping, going to Both after the engine is running. Much
safer. I have two impulse mags on mine and it behaves itself.
I hand-prop using one hand only. As I pull down I fold
myself so that my weight is carried back a little. The trick, as has
been mentioned, is to get pretty close to begin with. And make sure of
your footing. Anything slippery like snow or ice or wet grass, or
gravel on the pavement, can let you slide into the prop.
I don't prime my A-65 unless the temp is down around
freezing. It floods way too easily. Mags on, throttle at idle, and it
will catch on the sixth to eighth blade.

Dan