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
=mo
dload&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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