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Engine Controls
 | 2011.08.18: Since
my firewall forward installation is somewhat non-standard (vertical
induction FI is not uncommon, but not one of Van's supported
configurations...), I had to determine my own engine control cable
routing. Some builders with similar engine configurations have
used more-or-less the standard cable runs with slight modifications,
and others have strayed further. I decided to stray further
because I thought I could improve on Van's design.
One aspect of Van's design that I specifically didn't like was how the
throttle, mixture, and alternate air cables penetrate below the cabin
heater vent. This area is already congested with plumbing and
electrical, and running the engine control cables through there also
has them dangling near the co-pilot's feet / rudder pedals.
Instead I decided to run the control cables pretty much horizontally from the sub-panel and penetrate the firewall up high through the
recess area. Then on the forward side they drop down sharply
toward the throttle body. This took some planning and
head-scratching, but I'm very happy with the geometry I came up
with. It works well on both sides of the firewall and makes for
a much neater installation than Van's. (Note that I kept the
prop cable routing per plans. It worked well as is.)
I also didn't like how Van's uses plastic snap bushings for firewall
penetrations. Not very fireproof... So I used steel
spherical grommets, which take care of the fire concerns, as well as
securely anchor the cables while allowing them to penetrate the
firewall at oblique angles.
Now, no surprise, since this isn't one of Van's standard
installations, the lengths of control cables supplied in the firewall
forward kit didn't all work well for me (only the prop control cable
was fine, as it was a standard installation). Luckily, Van's did
have other lengths available from other aircraft or other engine
configurations that did work well for me. So I was able to get
by on other off-the-shelf cables from Van's, nothing custom. The
lengths of cables I ended up using:
| Throttle |
46.5 inch |
| Prop |
48.0 inch |
| Mixture |
50.5 inch |
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