Fw: TEST- now motor mount Poll

[george kennie]

Boy, I like that nose ring idea Bob! If you don't mind, I'm going to
steal it and I'll tell everybody where I got the idea so you wont get
cheated. THANKS!!!!
G.

Bob Pastorello wrote:

> Have to throw in a comment or two...    1.  Used the Hanson RotoRMount
> in 1997-98...good mount, lots of adjustability, and worked well - IF -
> you kept the center bolt snubber in the firewall snug enough, and
> maintained the tubing as it wore pretty quickly.  For me, using it
> with YS 1.40's at the time, it needed frequent adjustment.    2.   Did
> my own anti-rotational mount based on a sketch someone gave me at a
> contest once, lots of iterations of that principle, nothing really
> new....except ....  the Nose Ring... As some have already said - the
> Nose Ring, in my experience also, is a MAJOR contributor to noise and
> wear.  If too snug, way too much vibration is transmitted to fuse.
> You can feel it when holding the nose of the fuse during start/run
> up.  4C are bad, but the big 2 strokes pound like CRAZY and the lower
> the idle, the greater the impulse, the higher the amplitude of the
> vibration, although the frequency is lower.  The 2C hits nearly as
> hard, and TWICE as often as a similar sized 4C, and this is actually
> less vibration/impulse to deal with.  The total vibration issue is one
> of frequency of impulse, duration of impulse, and AMPLITUDE of
> impulse.  It's really a "cut and try" kind of issue to solve. One of
> the most productive experiments over a period of several years was
> discovering that the nose ring is probably much more important than we
> think.  I've used a variety of grommets, bushings, and settled on a
> dual-concave 3/16" thick O ring from McMaster Carr.  Sandwiched
> between 1/16" ply plates, and removable, it allows easy replacement. I
> also can testify that the MK Mount - again, in my limited experience -
> probably is something that is MUCH better left at the seller's
> pegboard, rather than in our airplanes.
> Bob Pastorello, Oklahoma
> NSRCA 199, AMA 46373
> rcaerobob at cox.net
> www.rcaerobats.net
>
>      ----- Original Message -----
>      From: Wayne Galligan
>      To: discussion at nsrca.org
>      Sent: Saturday, January 03, 2004 9:10 AM
>      Subject: Re: TEST- now motor mount Poll
>       Firing stroke impulse, inertia from moving parts, size of
>      components(prop, piston,square of stroke)  all have an
>      effect on vibration.  I have been trying a few things in
>      search of that all elusive vibration free setup. Does a 3
>      blade prop run smoother then a 2 blade prop? I have been
>      making nose rings out of 1/8" urethane sandwiched between
>      1/32" ply.  The urethane holds the nose in place without
>      having to have too snug of a fit at the crank end and it so
>      far doesn't seem to wear as quickly as lined nose rings.  On
>      my Entropy with an OS 1.40 is super smooth and quite at idle
>      and through most of the rpm range.  My Aries with the Mintor
>      1.70 bangs like a 4-stroke at idle and there was a
>      noticeable reduction in vibration when I switched the nose
>      rings.  I make a home made soft mount using Bob P.
>      instructions and it weights about 3.3 oz and handles the
>      Mintor quite well. you can view it at this
>      link http://www.rcuniverse.com/gallery/galleryCat.cfm.cfm?memberID=6463&CFID=862285&CFTOKEN=3b3a471-7dc5463c-19d1-4704-bd2f-605a2511e969 Wayne
>      G.
>
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