<<Closing off the gills would be the first thing (they add no value to the
plane). >>
I tried that.
It made no difference to CHT, oil or water temps. But why would it; those
systems are cooled independently to what goes on under the cowl.
However, (with the 912S air shroud fitted) the cylinder wall temperatures
went up SUBSTANTIALLY. So much so that I could easily believe that on a hot
day and an extended full power climbout they would quickly exceed the
maximum permitted (190C). Fortunately, I never experienced that
configuration before finding out this.
By closing the gills, 'competition' for cowl exit area is increased.
On the other hand, the temparature of the alternator regultator didn't seem
to be affected at all.
Duncan Mcf.
----- Original Message -----
From: Terry Seaver (terrys)
Sent: Thursday, September 20, 2007 10:39 PM
Subject: RE: Europa-List: Monowheel speed kit
I believe the biggest improvement in reducing drag would be found in the
engine cowl area. Closing off the gills would be the first thing (they add
no value to the plane). Second would be to clean up the radiator opening
and following duct, it is too large for the size of this engine and is
rather messy. Then clean up the radiator exit, it is very messy back there.
We carefully installed the Kim Prout main gear fairings and saw ZERO
improvement in cruise speed, which leads me to believe that the lower cowl
exit is so turbulent that fairing in the main gear (or even retracting it)
has little value. A magazine flight test on the Europa motor glider
reported that there was no improvement in glide performance gear up vs gear
down, which further supports my suspicion on the cowl problems.
regards,
Terry Seaver
N135TD, XS mono-wheel with 912S.
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Fred Klein
Sent: Thursday, September 20, 2007 1:40 PM
Subject: Re: Europa-List: Monowheel speed kit
I saw a increase of 3 knots average over several runs. Several of us here in
Florida, USA who have the XS monowheels, installed the speed kits looking
for 10 kts advantage. However it was not to be.
Though visually attractive, I've had my doubts about the mono speed kit.
For example, the flap hinge fairings have a large frontal area and are open
at the rear, neither characteristic will IMHO reduce drag. In my spare
moments I'm working on very narrow FG wrapped balsa skirts which slip over
the hinge plates and fit w/ minor FG moldings at both the pivot point and
wing surface intersection. I'll post pixs when I have something fitted.
I suspect the biggest source of drag not addressed by the mono SK is that of
the main wheel and wheel well, something which Alex Bowman has a handle on
and shown on pixs posted at:
www.europaowners.orgmodules.php?set_albumName=album149&id=DSCN0096&op=modload&name=gallery&file=index&include=view_photo.php
The exposed outrigger wheel is a source of drag which the speed kit fairing
doesn't address. Here are some pixs of a fully enclosed outrigger which has
a spring loaded afterbody which hinges up when flaps are deployed; airstream
on mini-tailplane locks it back down when flaps are raised...this is a
prototype not yet tested in flight...(hey, we're building experimental
aircraft, are we not?)
Fred
A194
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