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Jerry are you making full engine mounts
now?
Greg
Bob, Many
use the washers method. Built into the mount would be best. Better yet a
truly clever counter rotating prop set would be super. Then fin offset
could also be zero for max efficiency!
Bill
Jepson
My kit suggest to install
washers between my mount and the firewall to get the thrust I need. This
doesnt sound like a very good way to do it to me. Is this really the norm
for adjusting thrust?
Bob
Mears
Supermarine
Spitfire
-----Original
Message-----
From:
jerryhey@earthlink.net
To: flyrotary@lancaironline.net
Sent: Wed, 11 Apr 2007 3:22
PM
Subject: [FlyRotary] Re:
Mount offset
Bobby, I am sure
we can get it right. I am interested in Blake's suggestion because I
can do the drilling of the S-beam on the mill where I have more control.
We can also do something like you have just suggested by
measuring from a point on the S beam back to the firewall.
And then instead of moving the motor around, I can just move the
firewall. Same thing in reverse.
Jerry
I have been worrying about
accuracy when setting the offset as my fixture does not have an easy
point to measure from. I've considered a number of
schemes in recent weeks. Most would work but they were not easy
to implement. However, the last time the fixture was rebuilt (when the
S-beam was moved to the prop flange a year ago) I did put in a way to
pivot the engine mount at the prop flange but never used it.
All my engine mounts were straight ahead. Off set could be
managed with washers at the firewall.
Here
is the Dumb part:
For
at least two years I have used a laser mounted on the fixture to make
sure it was on thrust line. It fires right down the engine center line
to the "firewall" which has its own center line. I can move the firewall
back and forth, side to side, etc. When the laser points exactly to
the firewall center line everything is lined up straight ahead.
To dial in off set, all I had to do was mark the
calculated offset from the center line on the firewall and then pivot
the fixture until the laser pointed to the new mark. Honestly,
I did not realize I could do it this perfectly easy way which I myself
built, until a hour ago. It is now 3:30 am and I can finally get
some sleep. Jerry
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