Frans=0AI was talking about monowheel in ground effect.=0AGraham=0A=0A=0A
=0A=0A________________________________=0A From: Frans Veldman <frans@privat
epilots.nl>=0ATo: europa-list@matronics.com =0ASent: Tuesday, 30 July 2013,
10:23=0ASubject: Re: Europa-List: Tri-gear Flap Cross Tube Slot Length=0A
.nl>=0A=0AOn 07/29/2013 11:25 AM, GRAHAM SINGLETON wrote:=0A=0A> don't use
30 degree flap, Europa tested it and found you are starting to=0A> lose ail
eron control at the low speeds achieved in ground effect.=0A=0AI have some
trouble believing this (and even when it is true it is=0Aquestionable wheth
er this is still a valid reason for the XS with the=0Aincreased aileron spa
n and with more powerfull engines).=0A=0AWith higher flap settings you are
getting more drag than additional=0Alift. With 10% more flap (30 degree ins
tead of 27) you will get maybe=0Ajust 5% more lift. If the ailerons are ina
dequate for this tiny bit of=0Aextra lift I think they would have difficult
ies handling 27 degrees as=0Awell. Furthermore, in the XS the ailerons are
substantially increased in=0Alenght, significantly more than 5%, and should
have much more control=0Apower at low speeds! Even if control problems wer
e the limiting factor,=0Athan it is questionable whether the same limit wou
ld still be needed for=0Athe XS.=0A=0AI thought that the limitation in flap
was because of the 80hp engine=0Aused for the certification, which might h
ave lacked sufficient power to=0Aexercise a go around with full flaps under
full load (which is, if I=0Aremember correctly, a certification requiremen
t. For the same reason the=0Aolder Cessna's have 40 degree flaps, where the
newer ones have 30 degree=0Awhich was instantly rewarded with a 30Kg highe
r MTOW without any=0Astructural changes).=0A=0AFurthermore, in the tri gear
the fact that you have the option to use 30=0Adegree flaps doesn't mean th
at you will have to use this all the time.=0AThere are situations where mor
e flap would be welcome, and there might=0Abe situations where using less f
lap would be better. I can't see the=0Abenefit of the 26 degree limit. Of c
ourse for the mono you have no other=0Aoption than to land with full flaps,
so maybe in this case the=0Alimitation is justified.=0A=0AI know folks hav
ing drilled a new hole in the lugs on the flap control=0Atube, so that the
actuator can drive the flap further (and faster). No=0Acontrol difficulties
are observed even in quite a few nasty situations=0Awith 30 knots wind and
lots of turbulence. Instead the short field=0Acapabilities are somewhat im
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