The main causes of drag are the frontal area and drag from the aerofoils
(wings and tailplane). The bits that stick out contribute a little then
changing their drag coefficient does not have a big effect. I discussed with
Michel COLOMBAN the merit of putting fairings around the Ban-bi flap
brackets. He felt I would actually get a better return polishing the paint
surface of the wing to remove any orange peel. Although the change in
coefficient from polishing would be small the proportion of drag attributed
to the wing is large and a small % change on a large feature would be quite
noticeable. (Tailplane is now polished wings still to go)
Jerry
LTS@avnet.co.uk
www.avnet.co.uk/touchdown
----- Original Message -----
From: "Alan Stewart" <alan.stewart@blueyonder.co.uk>
Subject: Flying: Performance: Speed kit.
>
> Speed kit: Cruise improvement to standard Europa.
>
> A few months ago, I decided that it would be interesting if I accurately
> assessed the
> performance of my aircraft both before and after fitting of the "speed
kit"
> wheel and
> flap fairings supplied by the company.
>
> Tentative results, based on just one triangular route flown at maximum
> continuous cruise
> RPM of around 5500 (Flydat) has produced a TAS of 154 mph, after fitting
of
> the kit.
>
> My previous figures for 5500 RPM, taken in November gave results of 149
mph
> and 151 mph respectively (prior to fitting the kit).
>
> My initial conclusion is therefore that the speed kit has improved maximum
> cruise by
> around 3-5 mph in my aircraft, a bit of a disappointment if confirmed.
(the
> lower end of
> my expectation).
>
> This figure is obviously provisional. Later this week I'll perform further
> runs, which may
> confirm or contradict the initial figure. With a light aircraft and more
> forward C of G this
> time, I'm keen to make the comparison as fair as possible.
>
> I'm keen to produce a definitive set of figures for my Mark 1, Mono Europa
> with
> 912, standard fixed pitch WD prop and plenum mod.
>
> Alan
>
> NB. For all tests the Flydat measured RPM was actually within the range
> 5510 - 5540.
> Windspeed at 1100ft AGL on the test today was calculated at 70 degrees and
> 16 mph.
> (this concurs with
> http://www.meto.gov.uk/aviation/tafmetar/images/F214_1218.gif
> briefing chart which gives around 80 degrees and 15 knots for the area)
>
> Alan. D. Stewart
--
> --------------------------------------
>
> 14 Goddard Way 'phone : +44 1245 264186
> Chelmer Village mobile : +44 7801 287886
> Chelmsford, Essex CM2 6UR email :
> alan.stewart@blueyonder.co.uk
>
--
> --------------------------------------
>
>
|
