Measured the sound levels coming off the engine yesterday.
 Here's what
 we recorded:
 2500rpm - 97db
 5500rpm - 112db
 Sound levels were measured at a distance of 20 feet off the port
 side of the cowling in line with the muffler. C weighting, slow
 response.
 Mark (Rocky Mtn high)

 Thanks for the sound level data Mark.
 That is not too bad for 20 feet.
 Our standard is 30 feet so it should be be below 100 db at 5500
 RPM at 30 feet. We have recorded worse than 112 db at 30 feet.
 As I recall you have a 2 inch down pipe. Area 3.14 square inch.
 If you want to get it lower with no increase in back
 pressure try two 1.5 diameter inch down pipes. Total area 3.5 square
 inches.
 Do you have a blast tube on the muffler cooling pipe yet
 That tube might burn through if you don't get a blast tube
 0A
 on it.

 Paul Lamar

 Re noise level measurements:
 Usually the "A" frequency weighting is used to measure noise
 (when humans are the receivers). It corresponds best to human
 perception of loudness.

 On the time weighting (Slow or Fast) you should get the same
 answer for a continuous noise. OSHA does require the use of "S"
 for reportable measurements concerning workers exposure and
 possible hearing loss.

 Also, if you know the level at a given distance, if you double
 the distance-----------------------the level should drop by 6 dB
 (assuming a free field). Conversely, if you halve the
 distance---------------------the level should increase by 6 dB.

 Use hearing protection  90 db(A) if you want your ears to work
 well for your time on the planet Earth.

 Yes, a large area with low velocity will be much quieter than a
 small area with high velocity (same air mass flow). Compare the
 noise of an F-16 to that of a 747 (with 4 burning).

 cozyflyr
 20

 Paul:

 I don't know how to embed a picture of it, but attached is a picture of
 a DYNA ARC-2 (CDI) that has 2 independent triggers. It appears you can
 use any type of trigger----------------- so for a Mazda rotary you
 might use 4 triggers on a crank wheel. Cost: approx. $299. and you can
 fire it up tomorrow. Rich text editor off.

 Regards,

 cozyflyr

 If this is like your typical CD ignition system, and it looks
 like it is, it works fine but not what I had in mind. Most
 CDI's revert to a single spark around 4,000 RPM and above. IMHO
 not what we want. We want at least four sparks at 6000 RPM
 spaced 10 to 20 degrees apart based on the e-shaft angle on the
 lower plug AKA the leading plug.

 Paul Lamar

Paul,
Just a thought, couldn't we use an MSD system but trigger it off of the
older style CAS?  Since the CAS turns at 1/2 the crank speed, it would
provide multiple sparks at up to 8000rpm.

BTW, I'm in Denver visiting my daughter.  We flew the Lancair up from
Austin
on Saturday (688nm), averging 160 TAS at 8500msl.  Fuel burn was 11.4-12gph
per EM-2.  This was at 5100 rpm (c/s prop).  Everything went as planned.
Only problem, if you want to call it that, was with the voltage warning on
the EM-2 kept tripping.  This is for the MAIN alternator. The voltage
fluctuates between 13.98 and 14.5.  Whenever it goes below 14v, the
EM-2 trips the warning light.  I'll need to look into why it fluctuates
after we get home and adjust or replace the voltage regulator.  At 5100
rpm,
it indicates almost 10 amps to keep the engine and avionics going.  I'm
running dual 50A ND alternators and dual PC680 batteries.

The 20b [3 rotor] ran like a top.  Cruise oil temps were 205, water 188.
 Funny thing
was the EGTs dropped about 50-70 degrees after adding 15 gallons of 100LL.
Maybe I should be running premium mogas instead of 87.
Mark St.
Austin, TX


It runs at half speed but it has only two projections on the top wheel
trigger
and probably 36 on the lower wheel. If you used the lower wheel trigger
unmodified
the capacitor in the CDI ignition system would not have time to recharge.
It is not so much the number of triggers that is the problem. The problem
is the time it takes to recharge a suitable  capacitor. Using multiple
capacitors
that are pre-charged by a powerful high voltage power supply and triggered
by seperate triggers solves the problem.
http://www.rotaryeng.net/Why-CDI.html

Good performance Mark. 160 Kts is 184 MPH so the MPG was 15.33. Not bad for
184 MPH.  Too bad a car won't go 184 MPH and get 15.33 MPG :) My Cessna 182 gets
only 13 MPG at only 150 MPH.

14 volts is a bit high for a warning. Stock regulators are set to 13.9
volts  as I recall. Changing it out is not going to help. You need to change the
warning voltage setting.

Paul Lamar

Paul,
I agree that I need to reset the alarm limits.  I'll mess the settings when
I get back to home base.

Mark