2-c Hydemount - Mintor 1.70

[John Ferrell]

RE: RE: RE: 3M EnginesPlease elaborate:
"mount was stiffened slightly"
 
John Ferrell 
6241 Phillippi Rd
Julian NC 27283
Phone: (336)685-9606  
johnferrell at earthlink.net
Dixie Competition Products
NSRCA 479 AMA 4190  W8CCW
"My Competition is Not My Enemy"

  ----- Original Message ----- 
  From: Henderson,Eric 
  To: discussion at nsrca.org 
  Sent: Monday, May 12, 2003 8:50 AM
  Subject: 2-c Hydemount - Mintor 1.70


  One thing that I did notice while breaking-in the 1.70, (there is not much else to do except observe during this process), was the air-frame vibration.

  It was a very good result. I am using a 1.40 Hydemout A , 3/4 back plate to clear the header, with no nose ring. Because the 2-c shakes a lot less (than a 4-c) the mount was stiffened slightly. The result was a very smooth airframe performance . The controls did not buzz except some elevator at just above idle, for a brief moment. there was no aileron blur at all.

  I like this type of behavior because the servos last longer and there is less current drain due to the servo fighting the control service.

  Regards,

  Eric

  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Henderson,Eric
  Sent: Tuesday, April 29, 2003 12:02 PM
  To: discussion at nsrca.org
  Subject: RE: RE: RE: 3M Engines


  There is a time when a 2-c idles so low that it "bounces" as much as a 4-c at idle. Basically it is missing a beat so that it is firing at the same frequency as a slow running 4-c. At around 2000-2500 rpm they both smooth out. 

  I have extensive time on 1.40, and now 1.60, 2-cycles that lets me compare them with the big YS 4-c's and how they run and shake a plane. I have run both engine types with and without nose rings. 

  My goal was to get a plane that is shaken and "punished" the least! (Not ignoring sound issues BTW). I have observed that the best set-up is a non-nose ring Hydemount. All nose-rings add to airframe vibration. They provide poor isolation and have to be set with no side pressures to be iso-effective.

  All my nose ring installations cause aileron-buzz at certain - read most used in flight - rpm settings. This just kills the digital aileron servo!  

  The 4-c is the worst culprit by far. The DZ is a shaker and this may be why the fuel foams and causes dead stick's at low rpms. The L is smoother but the more nitro you use the more "bang" and thus the more energy to dissipate. 

  The smoothest set-up, by far, is a 2-c with no-nose ring. There appears to be no problem with the engine and prop torquing/twisting. The newer planes have room for a bigger hockey-puck-rear-plate. Planes with FG cowls are much easier to install without Herculean engineering of a nose ring support.

  I have put 4 and 2-cycles in the same airframe on the same mounts and same range of props and I have seen a distinctly better isolation when the 2-c is installed. The current batch of Webra 1,45, OS 1.40 RX and FI users can probably tell us what they are seeing.

  The "Mintor-men" will soon be reporting as well - right guys? 

  From a noise point of view my Hydeout with an L, is quieter that my Temptation with an OS 1.60, that is quieter than my Hydeout with a DZ.... Not by much however...

  Regards, 

  E. 




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