8
❑
1) Horizontal and vertical engine centerline marks are scribed
on the front of the firewall. Use a straightedge and pencil to extend
the horizontal and vertical centerlines to the edges of the firewall.
❑
2) Measure the width of your engine's crankcase, at the
mounting lugs. (example: an Irvine 1.50 2-stroke has a case width
of 2.03" between the mounting lugs, while a Saito 1.50 4-stroke
measures 1.80" between the lugs.).
Divide the case width
measurement by 2 and draw lines on the firewall on each side of the
horizontal centerline at that distance. These lines should be exactly
parallel to the horizontal center line. These lines indicate where the
inside edge of the engine mounts should be to fit your engine.
❑
3) Hold a straight-edge up tight against the engine bearing
surface of each engine mount, and then use a sharp pencil to draw
the thrust line location onto the side of the mounts. Be precise!
❑
4) One at a time, hold the engine mounts in place on the
firewall, lining up the pencil mark with the vertical centerline on the
firewall, while at the same time aligning the inside edge of the
mount with the case width marks you drew on the firewall in step
2.
When you have the mount properly aligned and square,
carefully mark the engine mount's bolt hole locations onto the
firewall with a pencil. Note that the holes in the engine mounts are
slotted. Make your mark in the middle of the slot, which will allow
for small adjustments of the final space between the mounts later.
❑
15) Locate two 4-40 x 3-5/8" Threaded Pushrods for the
ailerons, two 4-40 Solder Links, two 4-40 Hex Nuts, and two 4-40
Threaded R/C Links. Use a soldering iron (or torch) and resin core
solder to attach a solder link onto the unthreaded end of one of the
threaded pushrods. Thread a 4-40 hex nut onto the threaded end
of the pushrod, followed by a 4-40 threaded R/C link. Connect the
solder link end of the pushrod to the aileron servo output arm.
Holding the other end of the pushrod up next to the aileron horn,
adjust the threaded R/C link as needed to match its connecting pin
to the horn. Repeat this process to make a pushrod for the other
aileron. Remove the tape holding the ailerons in neutral position.
❑
16) Reconnect your radio system and check the aileron servo
action. Make sure the ailerons are operating freely and smoothly.
Final adjustments of all the control surfaces will be done after
assembly is complete. This completes the wing assembly.
ENGINE MOUNTING
It is assumed that most modelers will side mount their engine, to
keep as much of the engine as possible inside the cowling. The
EXTRA has a large amount of space inside the cowling for this
type of installation and it is highly recommended. Certainly the
engine could be mounted in any position, including upright or
inverted, as long as it is understood that a large part of the cowl will
have to be cut to clear it. These instructions will describe the
installation of a single-cylinder 2-stroke glow engine (Irvine 1.50)
mounted on its side. Other engine installations should be similar,
however there may be some differences that you will have to adjust
for in order to mount your particular engine.
NOTE: Size Limit on Glass-Filled Engine Mounts!
The plastic engine mounts provided in this kit are intended for
use with any brand 1.20 to 1.50 size 2-stroke or 4-stroke glow
engine.
Using these mounts with larger engines is not
recommended.
Larger engines should use an aluminum
mount. A wide variety of aluminum after-market mounts are
available and should work well on this airplane if you choose.