Excelleron 90

[Nat Penton]

Randy, Incheon, If you set your pipe length at 25" , plug to reflector, you can run the APC 15.5-12 @ about 7800. Much quieter and will go OOS , no problem.
  ----- Original Message ----- 
  From: randy10926 at comcast.net 
  To: discussion at nsrca.org 
  Sent: Friday, November 05, 2004 8:01 AM
  Subject: RE: Excelleron 90



  You are getting 10.5K rpm with a OS91FX in a 15X8.  Impressive.  I do not get much more than that with a 13X8 on the stock muffler, which is real heavy.  Think I should look into a wraparound header to use with the MACs pipe I have.  Not as long the 140 pipe and probably only need to modify the bellypan and not the fuse.

  Which perry pump are you using? V30?  is it on the firewall?

  Randy
    -------------- Original message -------------- 

    Randy,
    I need to build pipe tunnel in the bellypan. fiberglass lay up on a PVC pipe to make the tunnel. cut out the fuse around 4" behind the wing mounting. The fuse will also have some glass lay up to fill the cutout.
    The entire glass work will probably weigh similar to the unmodified plane.
    Karl's header is a wraparound. I think that is his specialty. Just tell him how high the header has to be reference to the exhaust center line.
    Above setup is for a stock OS 91SX-H w/ an extra head shim, Perry pump, Karl's header, 140 size carbon pipe (21" long). APC 15x8 with 20% had 10500rpm on a bench.
    I will have to run the engine again soon since I changed the crankshaft w/ 91FX's, Rear bearing with Boca SS. I am thinking about running the setup with 16 or 17" props as Nat Penton. (I gotta look for those E-mails from Nat)
    Ihncheol Park
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