3M 170 Flight report

Tue Apr 1 07:36:36 AKST 2003

Hi All,

This last weekend I installed a 3M 170 in my Alliance.  The header attached
to the engine with a dual o-ring system that allows for some adjustment.  I
did not have to bend the header to make it fit correctly.  I also used the
3M carbon pipe with header at stock length and ¼" gap between the pipe and
header.  Saturday afternoon I was ready to break it in:  25% Cool Power
Pro-Pattern, OSF in rear, OSA3 in middle, APC 17x10.  I primed the engine
with 3 flips of my finger over the carb at full throttle and reduced the
throttle back to idle.  I attached my glow driver to one of the plugs and
hit it with the starter.  The engine started IMMEDIATELY.  I raised the
throttle to about ¼ and let it warm up some.  I ran it 3 times, 5 minutes
each, alternating between low, mid, and full throttle.  During the first 5
minute session, the engine seemed to run just fine.  It would idle well, has
as perfect of a mid-range as you could ever expect from a new engine, and
accepted full throttle just fine.  The second session performed a little
better.  At the end of the third 5 minute session, I decided that any more
ground running was nonsense, and that this setup was ready to fly.  

Sunday morning I flew 5 flights.  Flight one could have been a contest
round.  The engine flew very nicely and was producing a thick smoke trail.
Flight two I leaned the high speed needle a couple of clicks (still
producing a thick smoke trail).  I tached the engine before flight three, it
was turning 8500 rpm (17 x 10) the flight still had a thick smoke trail.
Flights 4 and 5 were a pure joy and if it wasn't for having to pack for a
move to a new house, I would have stayed at the field.

In between flight 4 and 5 I forgot to fuel the plane as I was talking about
the engine to other folks and such.  It took me a second to figure out why
the engine stopped.  I figured out that the plane was out of fuel pretty
quickly, and refueled and resumed flights 4 and 5 without problem.  

I chose the 17 x 10 propeller because I did not want to load the engine too
heavily during initial runs (my preference).  The plane had unlimited
vertical - continuous rolls and snaps on uplines were easily done.  Thus
far, the most remarkable/impressive thing to me is that the low-end has
needed NO adjustment from break-in to flight.  Besides running out of fuel,
the engine has NEVER quit from break-in to flight unless commanded to by the
pilot.  First flight was the masters pattern - then some vertical stuff.
All positive or negative G, power-on or power-off, inverted or upright,
maneuvers, I never heard the engine pop, hesitate, or puff-smoke.  The
engine was "on" the whole time.  For instance, bottom of the center humpty,
or bottom of the reverse Cuban 8 with 2/4, bottom of the 3 turn spin - all
had smooth throttle when you were ready to advance.  The pipe seems to
perform very well without obvious jumps onto power or such.  I have not
checked it with a sound meter, but it seems similar to the ES carbon pipe
sound level, but with sort of  cross between carbon and AL  note to it.  

Everyone that has seen these engines remarks at how beautiful they are, or
that "they are a work of art" and this may be an initial selling point.
However, I think that as more flight reports emerge, we will see that their
performance is what gets them moving.  

Jim W.

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