> Nice set of ducts, I'll take a look at the cowl next time I'm at the
hanger.
> I am still somewhat uncomfortable with the side exhaust with an
unpressurized
> airplane. most homebuilts that I have flown in are drafty, including
the
KIS
> due to a pretty small seal area on the door flange. I know the stream is
> mixing with a lot of air, but having it go out the bottom seems better
to
me.
> I have determined that there is a real nice area for side cowl flaps for
> exit air between the top and middle tripod tubes.
>
> Bill Schertz
> KIS Cruiser #4045
Well since the rad is enclosed and shielded by the duct you can probably
wiggle
a couple of exhaust pipes back down and under along the left side of the
nose gear behind the rad. I'll see if I can do it in 3D. I forgot....
are you doing a turbo or NA?
BTW the aero bending load on those venetian blind cowl flaps is
considerable
so they should be carbon fiber on either side of 1/4 inch high density
foam or plywood.
Paul Lamar
I am doing normally aspirated.
Bill Schertz
KIS Cruiser #4045
I have decided to do my turbo this way. I can think of no disadvantages
and one major advantage is the back of the rad is totally unobstructed.
Paul Lamar
Perry Mick is using something similar. Note the small size of the
water rad even for the reduced power that Perry's engine is generating.
Note also the use of a NACA duct with a fuel sump in the middle of it.
IMHO it would work much better with a P51 style duct.
The big advantage of this scheme in a pusher is the outlet panel
slopes up so the pressure is naturally and highly negative in this region.
How is it working Perry?
BTW I think your front opening at the big end of the wedge is a bit small.
Paul Lamar
Sorry, I'm way behind on my email, just found this message.
I have about 160 hours on this new rad installation. Works
great as long as ambient temp is below 70F. Above 70F
it runs pretty warm in a long climb, close to redline on the
Mazda gauge. Cruise it cools off to mid-range, even with
90F. I think it is just the limitation of the small size of the
rad. I tried the VGs in front of the NACA, no difference.
I made a bolt-on scoop that doubled the inlet area to the
rad, no difference.
Awhile back I made an exit duct that covered the exit
in front of the fan, but it didn't work, cooling was terrible
so I had to remove it and leave the rad exit open to the breeze
again.
I agree about the size of the inlet.
--
Perry Mick
Duckt N7XR
http://www.ductedfan.com
Thanks for the update Perry. Is this the dimension you are referring to when
you say the "size of the inlet"?
Is this what the "exit duct that covered the exit
side of the rad with an exit hole into the low pressure area
in front of the fan" looked like?
If so I can now understand why that did not help.
Too close to the back of the rad near the front.
Best to leave it open and pump in a bit more air.
Paul Lamar
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