3M 170 Flight report

Tue Apr 1 12:09:08 AKST 2003

The two I have are both using the recommended A5 plug in both positions. 
This saves a few bucks over the OSFs.  With about 2 gallons through each, 
3 of the 4 plugs are still working (one had an early life failure after 
only a short time).  The engine with only one plug working is still 
running fine.  I never replaced the plug, because I'm still being Mr. 
conservative and running the engine in.  On the ground the only difference 
I can see between the 2 vs. 1 plug is the achievable low end idle.  I 
agree with Jim's observations about the carb.  It does not have the same 
midrange sensitivity that other engines have.  I've run a Bolly 120N, 
AeroSlave, Macs quiet pipe and Mintor pipe and found it tolerated pipe 
changes easily without affecting midrange.
   Testing with other plugs seems unecessary since the A5s produce the 
power and idling.  However, long term life of the plug and cost are also 
important factors.  The Bully 145 two plug head works great with KB1L 
plugs.  One set lasts me several months.  This is an inexpensive package, 
but don't try in on the Webra 145.  It seems to benefit from the OSF, but 
it is a single plug head.
   The only problem with the 170 so far is that at this kind of power, the 
exhaust seems to be much hotter.  I've blown 2 couplers when a gap exists 
between the header and pipe.  But I guess the 4c engines are probably 
still hotter.

I'll bring one to the Waco contest in 3 weeks for all you D6 boys to oogle 
over.  I'm painting my Aries#2 now so if it's done I'll have another 170 
mounted in there too.

--Lance

"Woodward James R Civ 412 TW/DRP (Test Ops)" 
<James.Woodward2 at edwards.af.mil>
Sent by: discussion-request at nsrca.org
04/01/2003 12:01 PM
Please respond to discussion

        To:     discussion at nsrca.org
        cc: 
        Subject:        RE: 3M 170 Flight report

I need to check Eric.  There were some I had handy.  I was certain that 
two OSFs were overkill, so in went the A3.  The instructions recommend the 
"OSA5".  I'm going to try a number of different plug combinations and 
check rpms and make other observasions.  I have some A5s on order now.
Jim

-----Original Message-----
From: Henderson,Eric [mailto:Eric.Henderson at gartner.com] 
Sent: Tuesday, April 01, 2003 9:41 AM
To: discussion at nsrca.org
Subject: RE: 3M 170 Flight report

How were the plugs after the break-in? My 1.60 with two plugs started to 
kill the OS F's

E.

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Woodward James R Civ 412 TW/DRP (Test Ops)
Sent: Tuesday, April 01, 2003 11:37 AM
To: discussion at nsrca.org
Subject: 3M 170 Flight report
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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