[NSRCA-discussion] NMP Pattern Header

Wed Aug 23 19:07:07 AKDT 2006

Jim have you had a DB meter on that Hatori yet?  I have one and like it quite well, Sean has that aftermarket pipe holder by Yashioka...or something like that...see it on RCU. The pipe comes off w/ a pinch of a couple springs, takes a second to get off. 

  Ive also got hundreds of flights on an NMP w/ no problems at all, using w/ the ES pipe which had a minor problem but overall a good system. I wouldve used again but the new plane wasnt a good fit for it.

  Brian

Jim Woodward <jim.woodward at schroth.com> wrote:
        v\:* {behavior:url(#default#VML);}  o\:* {behavior:url(#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape {behavior:url(#default#VML);}        st1\:*{behavior:url(#default#ieooui) }                Guys,

  I sold off nearly all my E stuff (only the Tanics left) and my trusty OS 140 RX setup.  Running YS now, I jumped into the new style of short Hatori pipe /header combination from Central Hobbies (P/Ns 822,821).  This setup looks to save about 2.0 oz over the Johnson header/Teflon coupler/Hatori pipe combination.  The installation is super clean and the muffler comes with “ears” and “stand-offs” for the mounting.  No more zip ties!  You just screw the muffler flanges down to the pipe standoffs.  The muffler has an O-ring that slip-fits onto the exit area of the header.  As there is no retention force of this attachment method, you must use the flange mounts to prevent the muffler from sliding aft.  

  The header is steel and appears solid, but not overly done.  The installation process is as follows:  pass hollow bolt through mounting flange, position brass washer over hollow bolt, screw hollow bolt into the motor and tighten down the flange.  Position gasket over flange, install header onto flange using the three metric screws.    Once the header is installed, the hollow bolt is completely concealed.  The only tip on usage I have is that it takes a few tries to get the “tightening” procedure down.  As you tighten the hollow bolt, the flange will rotate in the last ¼ turn.  Thus, you must ensure that when the proper tightness is achieved, the flange mounting pattern ends up in the correct position for the header to point down the center of the pipe tunnel.  150 words to explain, 5 seconds to understand once you have the system in hand.  

  My only idea for improvement to the header/flange system would be to install it first, then drill and tap an additional screw point into the system.  This extra screw should be positioned such that extended portion of the screw fits in between the cooling fins of the motor.  After installed, cut off the head of this new bolt.  What this would allow to happen is for the flange to be positioned 100% correct when you re-install it, and prevent it from rotating as the hollow-bolt is tightened. Instead of having to tighten and reposition a few times to get it right, you would be able to tighten it one time as there would be this new anti-rotation pin protruding from the backside of the flange.  

  However, GREAT system the way it is too – same one Sean was using at the 2006 nats.  Looks like header breakage is a thing of the past with this setup.

  Thanks,
  Jim W.

---------------------------------

  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Peter Pennisi
Sent: Wednesday, August 23, 2006 9:34 AM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] NMP Pattern Header

  Don,

  I am having good results with mine – 200+ flights later and going strong. You need a brace and you need at least 2 washers between engine and header + I washer inside – Total of 3 washers to be used.

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  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Don Filteau
Sent: Wednesday, 23 August 2006 2:23 PM
To: nsrca-discussion at lists.nsrca.org
Subject: [NSRCA-discussion] NMP Pattern Header

    HI People

    I just got back from the flying field.  My NMP Header blew off my 160 YS.  It pulled the threaded part that holds it to the engine through the header part. Has anyone had this happen to them? I have only put 5 gallons through this engine.  I am turning a 16.5x12.5 W APC at around 8500 rpms.  I am not sure if I like this header.  What are other people using on their 160'S?  I can take pictures to show people if they like.

    Don

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