Hi Fred,
Well my thoughts on this would be as follows:
1. Is there a problem in that area? Oil flow tests would show up any
separations
in that area or maybe someone with a dirty aircraft has flown through rain
and has some pictures of the surface flow patterns that were left. If there
is no obvious problem then I'd leave it alone.
2. If there is a problem then making a really good job of the wing fillets
would
be the best approach and maybe trying to maximise the radius of that fillet
(larger radius = better). The problem with a large radius is what happens when
you come to the trailing edge of the wing (or in the Europa's case, where the
wing ends and the flap starts). You need to lose that large radius and run
it out to nothing smoothly.
3. Sealing the wing against the fuselage would definitely be good. On gliders,
we use PVC tape but that only works if you have a small 'wing stub' moulded
into the fuselage that the wing butts up to. On a Europa I would say that some
high density foam on the inside of the wing root fillet would do the trick and
when the wings are fitted, the foam is compressed and thus forms a nice seal.
I.m not sure what gaps people have between the fuselage and the wing fillets
but try and keep them as small as possible.
In terms of drag reduction I would have thought that there is little to do on
the
Europa. It's already an excellent design and the use of composite materials
(and ability to build almost any shape) helps this. Compared to some homebuilts
on the market using the same engine, it has to be a very efficient machine.
Having said that, you notice the difference on a glider if the wing roots
are not taped and the controls are not sealed and so all these little bits of
attention to detail would add up and help reduce the drag that little bit
further.
Actually, that's an interesting point above. Out of all the homebuilts powered
with a 912S, there can't be many aircraft that are faster than a Europa. There
is the DynAero MCR1 (which I had an amazing flight in once) and that is very
fast but look at the size of it - it's tiny. Anyone have any other comparisons?
Phil
Visit - www.EuropaOwners.org
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