In my opinion, heat barrier of the =93works on my home heater unit=94
should be thought out a bit more for an aircraft.
A common glue on heat barrier material using aluminum and a fuzzy
material on the back pasted on with a silicon type glue burned very well
when exposed to direct flame. And it would not self extinguish. Test
before you install.
I use the firewall '2000 barrier which is much better than any other
product. The firewall aluminum/fiberfax/stainless sandwich material
available from aircraft spruce is marvelous for a firewall.
As far as our phenolic firewall, I put a torch to our resin firewall
some years ago and was astonished that it only charred and did not burn
or melt. 1000 F for about 5 minutes. Pretty good stuff. My
recollection is that it should only be good to about 750 before
breakdown.
It does transfer heat though. On the 912S I have never found it a
problem. On the 914, even in Florida, proper ventilation had meant a
comfortable cockpit. However, on one clients aircraft, I did add a
simple .016 in stainless reflector sheet shaped to the pilot foot well
face and mounted it with 3/16 inch spacers holding it off a bit to
provide dead airspace as the customer complained his feet were warm. I
flew the airplane in mid summer for about 10 hours and found it was more
comfortable, but he was enthusiastic that the heat reflector was perfect
for him. I didn=92t feel that the cost of firewall material was
necessary in this case, and the stainless sheet is inexpensive (for an
aircraft), and very attractive.
On the subject of cockpit ventilation:
The =93Ultimate Ventilator=94 is the unit I use most. I have found that
if you have a short exhaust pipe out of your cowl (Rotax), the vents
need to be above the hull halves. My trigear on a 75 knot climb using
AV gas leaves a bit of a gray exhaust plume on the fuselage and the NACA
vent placed any lower than 6 inches below the glass edge tends to allow
a whiff of exhaust in the aircraft. Those of you with very long pipes
exiting the cowl may not experience this. My NACA ducts placed per the
Classic ideas days which placed it down about 6 inches below the glass
to avoid the knees, must be left closed during climb out. In cruise it
is acceptable, but frankly are never used. The Ultimate Ventilators can
be aimed to deflect the incoming air directly to the pilot and
passenger.
I place the Ultimate ventilators in either the corner of the windscreen
glass about 1 inch from the edges knob pointing aft of course. It
requires courage to drill the glass but is fairly easy to do. Practice
on plexiglass to get the drill speed right. A number of folks have seen
mine in 12AY, and all of my build assists. It is not rocket science.
In new builds I place the vent in the area just below the windscreen.
Place it far enough forward to be usable around the canopy bow.
These Ultimate Ventilators keep me cool even in the hottest stickiest
days at low altitude in Florida. More importantly, my wife (she does
not do hot and sticky) is very comfortable with them. Of course I use
the 914 to get her as high as I can to around 10,000 to keep her
comfortable.
In aircraft using eyeball vents and the NACA, they work well but I find
the exit either so low that my knees get in the way, or it inhibits
getting the panel out if mounted higher. Panel removal is a very big
thing with me because that is where all the toys are. If I want to
upgrade a panel, I expect to pull it out aft with only a few screws and
cannon type plugs. Pulling out a face panel while in the cockpit is no
longer enjoyable, as I am getting old and fat and want easy. The
Ultimate Ventilators (also used on many Vans aircraft) are quite
directional and mounted to hit the pilot/copilot in the face or torso.
As for the feet, I=92ve seen a simple NACA that aims down through the
panel to the feet of the pilot. OK for pattern work but at altitude or
in winter, are taped up. (Note: on the RV 12 they have a 1946 Desoto
type vent, which when placed as most do, in a forward impact will rip
you leg open.) Pay attention to where things are in the cockpit to
prevent unnecessary injury, or extra maintenance work. That looks about
right needs to be thought out until that works really well is achieved.
Keep in mind, the air has to exit the cabin for the ventilation to work.
One can put in simple vents in the D panel in the baggage bay, or
spacers on the D panel screws to move it forward. The aft end of the
trigear is quite good as a suction source. Cutting out a 4 inch slot in
the door seal at the rear near the strut works well, as this is a low
pressure area, and rain can=92t get in as the channel drains the water
down and out.
The mono can be a problem (surprise!) as the owner who choses to leave a
larger hole in the bottom can tend to capture air and pressurize the
cockpit through the tunnel penetrations. If the aft wheel bay is closed
properly, and the cockpit slots are closed up and even lined with foam
on the inside to seal the gear, flap tube, brake, rudder cable and
throttle slots, one should not have a problem with unwanted cold or hot
air coming in. A tedious job, but if done so as to be maintainable and
interference free, rewarding.
My two cents also.
Bud Yerly
From: Christoph Both
Sent: Thursday, April 14, 2016 12:23 PM
Subject: FW: Europa-List: Engine Bay Heat Barrier
Hi Will,
I used the heat barrier product with over silica backed stick on. Glue
is good up to 300F, metal surface up to 2000F. I used this older
product, they now have a 24K new product I am not familiar with.
Stuck it onto the firewall at all not critical sections 2012. Still
sticks on after 250 hours.
http://www.thermotec.com
Critical sections were covered with an Aircraft Spruce both sides
stainless steel backed product:
Firewall-2000 Product# 05-00948 which I used to also cover the entire
motor mount cavity up to the firewall. Make sure you order a tube of the
2000F fire retardant "silicone=94 with it to seal all the edges. I
riveted the sheet with mounting washers to the firewall. This way the
entire footwell back to the tunnel is being protected for my TRI. Bud
suggested this and its good extra insurance.
Christoph
|