I tested the flaps down to 40 degrees, ailerons worked just fine.
Ivan
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Frans Veldman
Sent: 30 July 2013 10:23
Subject: Re: Europa-List: Tri-gear Flap Cross Tube Slot Length
--> <frans@privatepilots.nl>
On 07/29/2013 11:25 AM, GRAHAM SINGLETON wrote:
> don't use 30 degree flap, Europa tested it and found you are starting
> to lose aileron control at the low speeds achieved in ground effect.
I have some trouble believing this (and even when it is true it is
questionable whether this is still a valid reason for the XS with the
increased aileron span and with more powerfull engines).
With higher flap settings you are getting more drag than additional lift.
With 10% more flap (30 degree instead of 27) you will get maybe just 5% more
lift. If the ailerons are inadequate for this tiny bit of extra lift I think
they would have difficulties handling 27 degrees as well. Furthermore, in
the XS the ailerons are substantially increased in lenght, significantly
more than 5%, and should have much more control power at low speeds! Even if
control problems were the limiting factor, than it is questionable whether
the same limit would still be needed for the XS.
I thought that the limitation in flap was because of the 80hp engine used
for the certification, which might have lacked sufficient power to exercise
a go around with full flaps under full load (which is, if I remember
correctly, a certification requirement. For the same reason the older
Cessna's have 40 degree flaps, where the newer ones have 30 degree which was
instantly rewarded with a 30Kg higher MTOW without any structural changes).
Furthermore, in the tri gear the fact that you have the option to use 30
degree flaps doesn't mean that you will have to use this all the time.
There are situations where more flap would be welcome, and there might be
situations where using less flap would be better. I can't see the benefit of
the 26 degree limit. Of course for the mono you have no other option than to
land with full flaps, so maybe in this case the limitation is justified.
I know folks having drilled a new hole in the lugs on the flap control tube,
so that the actuator can drive the flap further (and faster). No control
difficulties are observed even in quite a few nasty situations with 30 knots
wind and lots of turbulence. Instead the short field capabilities are
somewhat improved.
Regards,
Frans
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