Nigel Charles wrote:
Some of us have an excellent two part composite firewall provided by
Graham Singleton. This uses phonelic resin (as per the rest of the
firewall). This has two major advantages.
1. It is much easier to cut to shape and modify to accommodate wiring,
pipes etc. 2. It does a much better job as a firewall as it fits the
aperture very accurately.
>>>>
We installed Graham's firewall in N135TD, and I agree with both of your
comments. It also fully encloses the rudder cables and their return
springs, eliminating the leakage through the slots for these items.
However, there are a couple of other considerations that may be
significant to some builders. First, the lower firewall hides the lower
engine mounts, as well as the landing gear bungee cord. Since it is
rather difficult to remove this part of the firewall, each builder
should weigh how important it is to inspect these items regularly,
versus how much effort he is willing to expend in doing so.
Second, the lower firewall extends forward much further than the
stainless steel version, reducing the exit area for cooling air through
the cowl, particularly in a monowheel XS. This might not be a problem
in some Europas, but ours had excessive temperatures in the lower cowl.
In the process of trying to improve the airflow through this area, we
eventually removed the lower section of the phenolic firewall, replacing
it with something similar to the factory design. It is possible that
the baffling arrangement that eventually solved our problem would have
been effective even with the full phenolic firewall in place, but it was
too late to try this combination at that point.
Dave DeFord
N135TD
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