Hi John,
Our molten tie wrap was on the stb firewall next to the oil reservoir, some
distance from the exhaust components.
We removed our '914 turbo inlet' duct and glassed over the hole. It is not
clear what effect it might have if it were there.
We have had our oil cooler lowered to a staggered position from the
beginning, and still have some cooling problems on the ground. We have also
faired in the lip of the cooling duct inlet, added an aluminum lip to the
bottom, rear, of the cowl, and provided a ramp at the radiator inlet to try to
improve flow on the ground, with very limited success. We are still looking at
this one.
We cut back the rear, upper surface of the aluminum cooling duct, about 6
inches. With only a slight improvement in lower cowl temps. It would appear
that any increased cooling air flow simply went across the top of the engine,
down the back side, and out the increased exit area provided, bypassing the hot
exhaust areas. This extra outlet area is probably necessary for good cooling,
it just wasn't enough change, on its own, to make a big difference.
The upper cowl louvers don't seem to help much, and may in fact be counter
productive. We have taped over three of the four openings in each with no
noticeable rise in upper or lower cowl temps. There is little heat source in
the upper cowl area, compared to the lower cowl's exhaust system. Passing air
---From the eye ball vents adjacent to the spinner through to the upper cowl
louvers cools an already cool upper cowl area, leaving the lower cowl area to
bake.
One of the largest contributers to lower cowl temperatures seems to be the
exhaust pipe hole in the port side of the lower cowl, and the effects pitch and
yaw have on it., changing it from a lower pressure outlet one moment to a
higher pressure inlet the next. This effect, during the transition from climb
to cruise, causes a rise of 150 deg F in the lower, right cowl area.
Terry Seaver
John Wigney wrote:
> <<<<Our initial test flight showed lower cowl temps peaking at 400 F,
> sustained temps of 375 F, with an OAT of about 35 F. It is quite likely
> then that on a hot day our cowl temps are up to 450 F.
>
> Has anyone else noticed excess heat in the lower cowl?
> Any suggestions on what mods to the cowl will get rid of this heat?>>>>
>
> Hi Terry,
>
> Very interesting. I will keep an eye on this problem for my 912S mono XS. I
> have several nylon wire ties and nylon spiral wire loom sleeves on my engine
> but have not seen a problem yet. I did have some corrugated split loom
> sleeve but that was polypropylene and softened rapidly and I have now
> removed all that. On my cowl, I have put in the standard upper NACA carb
> inlet as per the manual. On the lower starboard surface, there is the inlet
> which is designed to feed the 914 engine turbo installation. I just opened
> this up so that air blows into the lower engine bay. I had thought that this
> may be a drag item and considered fairing it over later but will consider
> that change more carefully now. What have you done with that lower inlet on
> yours ?
>
> There is one item you might consider if you have not already done so. I
> installed my oil cooler in the position as shown in the manual i.e. behind
> the coolant radiator and up to the top surfacer of the duct. I found during
> my initial engine power runs on the ground that I was getting overheating
> and on checking around other owners and with Europa head office found that
> many builders have lowered the oil cooler with longer bolts and spacers to
> be at the bottom of the duct so that it gets inlet air through the gap
> between the radiator and cowl inner surface. This seems pretty obvious but I
> just followed the book ! Since OAT's here in North Carolina are low at the
> moment and cooling is much better in flight, I do not have a problem now but
> intend to do that mod later. Anyway, during these discussions, a builder in
> Florida with a lot of flight time mentioned that it is important to provide
> additional area for air to exit the cowling since the upper shark gill
> exits are inadequate. He recommended that the upper surface of the aluminum
> cooling duct be cut away behind the oil cooler. This gives a greater exit
> area for the hot air to depart the engine bay and is a mod I intend to carry
> out.
>
> Any comments ?
>
> Cheers, John
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