On 08/06/2012 04:18 PM, Fred Klein wrote:
>> How much air is going to this gap with the flaps extended? Is it
>> possible to make the underside of the wing flush with the flaps when the
>> flaps are retracted?
>
> ..."possible"...but not necessarily desireable...this type of gap seal
> was installed on Cessna 180s with decidedly mixed results...
I know it was an option on Cessna's but I didn't know about the mixed
results.
>> This would reduce the size of the gap with the flaps extended, does
>> this have consequences?
>
> I would think so, and not necessarily positive. I'd classify the Europa
> flap as a "slotted flap" which is generally designed to allow
> substantial airflow thru the slot which I believe is intended to promote
> the attachment of the boundary layer to the upper surface of the
> flap...a good thing, no?
Yes. But the current slot is a 90 degree corner, and apperently you can
also put cell foam in it as a seal. Id doesn't look like it allows lot
of air through. That's why I wondered whether some "lip" at the bottom
of this slot would make things different.
> I would think that if the compressible flap gap seal which John Lawton
> recommends was sliced from a circular rod of closed cell foam (known as
> "backer rod" and used in the US for sealing the joint between concrete
> and the sill plate of a wood wall) would have minimal disruption of
> airflow thru the slot.
Yes, but he mentions in the email that "the XS-wing looks like it has
been designed with a seal in mind, because it has a flat area at the
bottom of the slot." But at the bottom of the slot the gap is at its
widest point, far too wide for a foam seal. So I'm a bit confused here
as what he means.
> As you can read from my use of terms that I have only a fuzzy awareness
> of this stuff, so take my comments with a grain of salt.
Same here. I hope to find someone who can shed some more light onto this
matter.
Frans
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