Mintor Review

[Amir Neshati]

I ran the following engines on their stock mufflers and tuned pipes. The same prop, day,
plug, fuel, etc. was used, just changed the exhausts from the stock mufflers to the 
tuned pipes:

OS 25 FSR gained 1200 RPMs with a Mac's pipe

OS BGX 2.1 cubes gained 900 RPM with an OS pipe

Tartan twin 2.6ish cubes gained 600 RPMs on Chapman pipes

Zenoah G-62 gained 700 RPMs on a German muffled pipe. This was the same pipe
the German fliers used at the TOC...I think it was '92ish time.

The airplanes became different animals once the pipes were added. Horse power (or camel
power where I'm from) is equal to the RPM increase cubed. Let's take the G-62 for example,
it tached 7000, then tached 7700 on a pipe...
That's a 10% increase in RPMs....cube 10% and it's a 33% in horses. 10% can be written
as 1.1          1.1x1.1x1.1=1.33 or 33% increase.

The BGX went from 7500 to 8400....That's 12% more RPMs, so it's 1.12x1.12x1.12=1.40
or 40% gain in horses...

I then adjusted the prop size to achieve the desired performance I was looking for. With the exception
of the Tartan, the rest of the engines were stock. The G-62 was converted to glow. Tinkering with
exhaust port timing would have increased the horses even more, but I was content ;-)

Later,
Amir






  Karl's right.
      Dean
    -----Original Message-----
    From: Karl G. Mueller [mailto:kgamueller at rogers.com]
    Sent: Thursday, April 01, 2004 3:37 PM
    To: discussion at nsrca.org
    Subject: Re: Mintor Review


    Steve,

    With proper exhaust port timing and setup with a good pipe you will
    loose that bet. My bet is that you will gain closer to 20% improvement
    in power, of course with more power comes a higher fuel consumption
    as well. Most engines are very conservatively ported in the exhaust
    timing to run on a muffler as well as on a pipe. Just an other compromise
    by the manufacturers.

    Karl G. Mueller
    kgamueller at rogers.com
         
      ----- Original Message ----- 
      From: Patternrules at aol.com 
      To: discussion at nsrca.org 
      Sent: Thursday, April 01, 2004 9:49 AM
      Subject: Re: Mintor Review


      In a message dated 4/1/2004 9:28:50 AM US Eastern Standard Time, d.pappas at kodeos.com writes:
        Mintor 140 article, how does it run on a muffler as
        opposed to a pipe. I would expect some loss in power
        but also a loss in cost.
       I don't use pipes on any on mine engines Jeff Hughes and I have been using the Bolly 590r which is a muffler, no tuning head aches, no midrange problems, if you change props, fuel or anything else NON PROBLEMS, I have been running the Mintor 140 with it and it runs super, don't know how much less power you get from just running a muffler but I'd bet it's not over 5%, I use Coolpower 15% fuel.


      Steve Maxwell
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