[NSRCA-discussion] Pipe for OS 140RX

Mon Feb 13 11:55:58 AKST 2006

With an engine like the YS, the valve action precludes a lot of real tuning as in the principles of a 2-C pipe and all of that sexy resonant wave bouncing etc. - (You guys in the hotel room - no reaching for the Kleenex...........)

With the YS's the back pressure is much more of and issue. The diameter of the header needs to at least be equal to the exhaust port diameter. I also proved to myself that you can get more rpm if the header diameter does not expand too soon or too much.

A large volume ES pipe would give a 200 rpm increase over the Hatori's of the day. I got the best results and sound reduction from the long skinny ES 2-c pipe that was designed for narrow pipe tunnels. It was not easy to use on the OS 1.40 but proved not to be a waste of money when it was used on a YS.  

The 1/2" Teflon connector could be anywhere from 4-9" long and did not change the "tune" or rpm.

I did use heat sinks to protect the CF from melting with the high 4-c gas heat at the neck of the pipe. I made finned ali-reducers to connect the pipe to the 1/2" Teflon. This set-up worked so well that one year Quique thought I was running the early DZ's.

I just could not find a system the made my planes look the way he flew them :-)

Regards,

Eric. 
  ----- Original Message ----- 
  From: DaveL322 at comcast.net 
  To: NSRCA Mailing List 
  Sent: Monday, February 13, 2006 3:21 PM
  Subject: Re: [NSRCA-discussion] Pipe for OS 140RX

  I only messed with the 4Cs when the pattern rules essentially forced the use of a 4C to be competitive - so 90% of my 4C tuning was with the SF and AC.  Nonetheless, I did find changing header diameters and lengths could improve things slightly - attributable to more efficient scavenging during the exhaust cycle.  As basic theory would suggest, relatively narrower and longer header/pipe inlets seemed to help midrange torque, while relatively larger diameter stuff helped top end power.  No where near the gains in performance possible with a 2C tho.  I seem to recall Pappas publishing some actual numbers years ago in FM.

  Dave

    -------------- Original message -------------- 
    From: "Bill Glaze" <billglaze at triad.rr.com> 

    Dave:
    How effective is pipe length experimentation with the Y.S. engines?  With the large V-8 engines I used to race, header length, while not critical, was still effective for squeezing out the last horsepower.  (Yeah, we got it down to that kind of increment on the dyno.)
    Bill Glaze
      ----- Original Message ----- 
      From: DaveL322 at comcast.net 
      To: NSRCA Mailing List 
      Sent: Monday, February 13, 2006 11:05 AM
      Subject: Re: [NSRCA-discussion] Pipe for OS 140RX

      It is nice that we have several very good options available for exhaust systems.

      With regard to tuned pipes, to truly evaluate the capability of the pipe, they do need to be tuned.  And how they are tuned is often different for different users depending on priorities for power, torque, sensitivity, etc - to say nothing of matching the tune length to airframe drag and weight, prop, flight style, etc.  Simply plugging the pipe onto the end of a header is rarely going to yield the best performance for that pipe.  Similarly, making comparisons between different pipes that have not been tuned is not much more than a chance comparison.  Granted, some pipes have a broader sweet spot, but they all benefit from proper tuning.

      Regards,

      Dave

        -------------- Original message -------------- 
        From: "David Flynt" <dflynt at verizon.net> 

        > Or should we spark up a rivalry like OS vs YS, JR vs Futaba, Composite vs wood, etc? That could be entertaining =)

        Mike, I like the ES also.  Now what was that composite vs wood rivalry all about?

        David
          -----Original Message-----
          From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Mike Hester
          Sent: Sunday, February 12, 2006 10:03 PM
          To: NSRCA Mailing List
          Subject: Re: [NSRCA-discussion] Pipe for OS 140RX

          I think when it comes between the aeroslave and the ES pipe, it's personal preference. With some notable but subtle differences.

          Here's what I noticed:

          The ES 2C140M80 pipe I use is 3.2 ozs, the Aeroslave is right at 3 ozs. it's pretty much a wash.

          The transition is bit little smoother on the ES. 

          The Aeroslave pipe gives about 100 rpm more on the top end. 

          (both above using standard length header, no cutting and tuning). 

          The Aeroslave costs less, but has been difficult to get in the past. I believe that may no longer be an issue. 

          The ES is much more easy on the eyes.

          The Aeroslave is physically smaller, and could fit better in tight installations. I've found this to be true on a few applications.

          The ES (for me) has proven very very durable. I've never worn one out, ever. I have one with almost 2000 flights on it. It was involved in a crash before I got it, The airplane was completely destroyed, head in full speed...the pipe wasn't scratched. It only had about 50 flights before the crash.

          Also Ed Skorepa has been very good to me service and price-wise, so I suppose there's some loyalty involved. Lance has also been great to me, and so I also am running an Aeroslave in my older Black Magic prototype now. 

          So, I run both. The ES is more "bling" and a little smoother, the Aeroslave is more business-like and stronger on the top end but stumbles just a tad in the mid range. 

          I'd run either in a heartbeat. I just slightly prefer the ES for my newer stuff. You can't go wrong with either.

          Or should we spark up a rivalry like OS vs YS, JR vs Futaba, Composite vs wood, etc? That could be entertaining =)

          -Mike
            ----- Original Message ----- 
            From: David Lockhart 
            To: NSRCA Mailing List 
            Sent: Sunday, February 12, 2006 11:27 PM
            Subject: Re: [NSRCA-discussion] Pipe for OS 140RX

            I've run most of the pipes available in the past couple years on both the OS (RX and EFI) and Webra (145 and 160).  The "best" pipe depends on how you prioritize power, throttle response, noise, weight, and price.  If I needed to buy a pipe today, I'd go with the Aeroslave as I believe it is best or very close to best in all the categories I listed.

            Regards,

            Dave

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