Dick Gregory wrote:
Hi all,
A bit of rambling here. Any advice is very welcome.
My 13B is scheduled to be delivered on Thursday. I have been holding off on
some of my design decisions until I can get a physical look at how things
are going to fit.
Since the LongEZ firewall is so narrow, things are tight. I really wanted to
eliminate all bumpouts on the cowling, but I don't think it can be done.
Also, you guys have convinced me to keep the male belly scoop instead of the
NACA design. In addition to the belly scoop I will need one for the oil
cooler. I plan to put this one under the left strake similar to Perry's. I
don't know whether to draw induction air from one of the scoops or put a
separate one under the right strake.
Paul has a photo of my new oil cooler duct, that mounts in the left
wing root area. Maybe he can dig that one up.
I think I will put a bumpout under the bottom corner of both sides that flow
back from the scoops. This will provide room for the oil cooler ducting on
the left, and a muffler on the right.
I have the oil cooler inlet on the left bottom, the airflow sensor inlet on
the right bottom and the rad on the bottom, fed by naca. I think you
should stay with the male inlet, as we've discussed on here before, that
should work better than a naca for a radiator.
I am considering a radiator from the Chevy S-10 pickup. It is 15 by 26.5
inches. 1 inch or 1.125 inches thick depending on transmission and A/C. I
wanted to mount it horizontally above the belly scoop for updraft air, but
that would make the cowling very fat close to the prop. If I drop the front
to the bottom of the scoop and raise the back just below the redrive I can
get a much better taper. This means downdraft air. Will I have problems with
debris damaging the radiator in this position? Perry, what kind of results
have you seen so far with your new setup?
My new rad works just as well as my old one. It is a downdraft
configuration now. Paul has some pictures of that too. It is a C&R
racing 13 x 18 x 2, customized such that they didn't install the filler
port, and replaced the bungs with 1" npt ports. You could maybe
have slightly larger ports put on.
But... I'm still not running full RPM yet as compared to redrive guys.
My max RPM is 5100 in climb and 5400 in cruise. I'm still having
marginal oil temp, 220 on a warm day during climb.
I think if I was running 6500 RPM I would have a serious oil temp
problem. Still can't figure it out except that maybe the '86+ oil
coolers are better than the '82 I'm using, even though they look
exactly the same on the outside except for mounting tabs and
port orientation.
Ron Gowan, are you on this list? Did I hear that you are changing yours from
plugs up to pan down configuration? If so, do you have any magical solutions
to the space layout challenge?
Dick Gregory
LongEZ N613NC
Houston, TX
Sounds good so far. I don't think Ron Gowan is. At least under the
name Ron Gowan. Want some more pictures of Perry's set up?
Here is a good picture of his motor mount on the test stand.
It is a bit overkill and one could go down on tube size to about
5/8 inch OD.
Ron Gowan mentioned on the other list he had a similar problem to
mine, failed o-rings. But his was much more severe, he overheated
the engine in the air, and I think his rotor housings were warped.
He thought that if the engine had been in the normal orientation he
would have had a little more time before it overheated.
BTW Perry did you ever get around to measuring the air pressure
in front of the oil rad?
Paul Lamar
No, I haven't had the cowl off. In the inlet side I plugged the end
of the tube and put the three little holes in like you said. But I didn't
do this on the exit side. This could be where I'm getting some error.
Since I can't fly anyway, I guess I'll take the cowl off and fix the
exit tube.
I still think I'm sucking more air out the back than is coming in the
front, even at 150 mph. The inlet in that new oil cooler duct is about
3 x 5 inches I think.
--
Perry Mick
Duckt N7XR
http://www.ductedfan.com
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