GREATPLANES Large Engine Isolation Mount User Manual
NOTE – The rubber grommets are designed to absorb the
vibration energy from your engine. It is normal for them to
wear during usage.You should inspect the grommets for
excessive wear after the first five hours of operation and
every ten hours
thereafter (more often if excessive wear is
noted).
Replacement grommets are available at minimal
cost. You should replace the grommets when wear
becomes noticeable.
PREPARE THE ENGINE MOUNT:
❏
1.The 1/4" Birch Ply Mount has been designed for use
with a variety of models & engines.It ma y be necessary to
modify it for your particular application. For example, the
dashed lines on the upper corners of the enclosed
template, show where to cut off material to fit the
Dynaflite
™
Super Cub or Dynaflite Fly Baby.
❏ 2. Compare the Ply Mount with the side and top views
of the fuselage plan to determine if you will need to trim
the height or width of the mount, BUT DO NOT CUT
IT YET.
❏ 3. Using the SIDE VIEW of the fuselage, place your
engine at the proper location and orientation. Be sure to
align the
center of the crankshaft with the thrust line shown
on the
plans. Place the Ply Mount against the back of the
engine.Move the Ply Mount up or down to obtain the best
location for mounting it to the fuselage. Mark the Ply
Mount for the vertical height of the engine mounting bolts.
Also, mark the location of the Ply Mount on the firewall.
❏ 4. Use the TOP VIEW of the fuselage to place your
engine at the proper location and orientation. Be sure to
align the center of the crankshaft with the thrust line
shown on the plans, noting any thrust angle.Place the Ply
Mount against the back of the engine.Mo v e the Ply Mount
left or right to obtain the best location for mounting it to the
fuselage. Mark the Ply Mount for the horizontal location
of the engine mounting bolts. Also, mark the location of
the Ply Mount on the firewall.
❏ 5. Mark the center line locations of the holes to be
drilled for the engine mount bolts, BUT DO NOT DRILL
THEM YET .
❏ 6. Determine how you will mount the Ply Mount to the
aircraft firewall, keeping in mind that the grommets will
cause the Ply Mount to be spaced 1/4" from the firewall.
On Many airplanes it will simply be a matter of bolting it
directly to the firewall with the supplied bolts. On others
you may need to build spacers onto the firewall. If you
have not yet mounted the firewall in the aircraft, you may
be able to adjust it to better fit the Ply Mount.
MOUNT THE ENGINE TO THE PLY MOUNT:
You are now ready to drill the engine mounting holes in
the Ply Mount. Remember the old carpenters saying ‘Measure twice, cut once’.
❏ 1. Dr ill 1/4" holes at the locations you marked for the
engine bolts.
❏ 2. Mount the engine to the Ply Mount using 1/4-20 x 1" bolts
and 1/4" flat washers (Not Supplied).
MOUNT THE ENGINE AND PLY MOUNT TO THE
FIREWALL:
You must now determine where to drill the holes for the
mounting bolts. When doing so, keep in mind the
clearances needed for the rubber grommets.If your mount
comes with pre-drilled holes, skip to Step 4.
❏ 1. Place the Engine/Ply Mount on the firewall using the
reference marks you made earlier.The Ply Mount will not
fit directly against the firewall as the engine mounting bolts
are on the rear of the Ply Mount.
❏
2. Referring to the plans, double check the location
again.
Determine the best location for the mounting bolts,
then mark the Ply Mount for the mounting bolts. Remember
that the rubber grommets will be mounted to the front and
rear of the Ply Mount and could conflict with parts of the
engine. Also keep in mind any parts of the airplane
structure that could conflict with the mounting bolts or
blind nuts.
❏
3. Drill 1/2" holes in the Ply Mount at the locations you marked.
❏ 4. Install the eight rubber grommets in the Ply Mount.
Place the Engine/Ply Mount back on the firewall and mark
the location of the holes to be drilled in the firewall.
❏
5. Drill 5/16" holes in the firewall at the locations you
marked. Install the 1/4-20 blind nuts in these holes.
NOTE - The engine bolt heads on the rear of the Ply
Mount
will touch the firewall.Mark the firewall where the
bolt heads
touch.
❏
6.You will need to cut or drill clearance holes where the
engine bolts touched the firewall. Either partially dr ill into
the firewall with a 1/2" drill or use a Dremel
®
MultiPro™tool
to hollow out a clearance area.
❏ 7.Bolt the Engine/Ply Mount to the firewall using the
1/4-
20 x 1-1/4" bolts and 1/4" flat washers. If you had to
install spacers on the firewall, you may need to obtain
longer bolts.
ENGINE SIDE VIEW
Parts List
Part# Qty. Description
PLYS018................(1)............................1/4" Birch Ply Mount
SUB2000 ..............(1)..............................Hardware Subpack
Hardware Subpack (includes the items listed below):
SCRW114 ............(4) ............................1/4-20 X 1-1/4" Bolt
WASHER03 ..........(4)..................................1/4" Flat Washer
NUTS020 ..............(4) ................................1/4"-20 Blind Nut
RBUSH01..............(8) ..................................Rubber Bushing
Large Engine
Isolation Mount
™
ASSEMBLY INSTRUCTIONS
Great Planes Model Manufacturing
P.O.Box 788
Urbana, Illinois 61803
(217) 398-8970
© 1997 V1.2
The Large Engine Isolation Mount™provides a simple
but effective w a y to mount your large gas or glo w engine.
It is effective at dampening normal engine vibration,
which in turn will extend the life of both your airplane and
your radio system. It will also effectively reduce noise
due to vibration.
Caution – Proper balancing of your propeller is
essential. This engine mount system WILL NOT
compensate for an out of balance propeller. The rubber
grommets are designed to work under normal engine
vibration and will be quickly damaged under heavier
than normal vibration.
Printed In USAGPMG2000P01
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