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REFLECTOR: Ducting, again



Jeff barnes tells me:
>Hi David,
>please re-post the original msg...it did not get forwarded. 

So here it is again. 

Since that time I have looked carefully at Bill Schweitzer's 
plane, and I see that there is no easy way to run a second 
duct (large enough for the water hose) through the canard 
bulkhead. The problem is that the rudder cable arm is in the 
way of another duct sitting on top of the existing duct. The
second duct also cannot go below the existing duct because
it will interfere with the seat. If I snake the duct up higher,
there is the possibility of an air bubble getting stuck at the 
high point, thereby restricting flow. If the duct ran on top of
the existing one along most of the length, and then went to
the floor, it looks like the radius would have to be too sharp if
it is to stay out of the way of feet and rudder controls. Kinks I
do not want.

What does seem like it will work is to leave the duct
passages through the firewall and bulkheads as they are, and
then, because of the 'open' installation technique which
started this thread, I'll be able to divide the existing duct into
one space for the water hose and another for everthing else.
Because so much of the 'everything else' comes up before
the canard bulkhead (and thus before the rudder arm), the
duct for those cables could be made a little larger than
normal and still clear everything else. I found a high quality
(and very expensive ... $14 per foot!) hose which has 1" ID
and 1.25" OD, good to 40 psi and 425 F. The radiator cap will
be 10 psi, and the water pump bearings start leaking at about
25 or 30 psi, so this should work. 

I still do not know if I will be able to get a radiator in the nose
to supply enough cooling, so this may all be moot. As has
come up, one engineer I have worked with wants a belly-pod
cooler like the P-51.

Cheers,
David

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