Valid point. VGs aren't for every airfoil though depending on the mission of
the
aircraft they can benefit even a laminar wing (some pilots desire all the short
field performance or slow speed safety they can get).
Keep in mind that VG's are also very useful for increasing tail effectiveness
(either
rudder or elevator) and also for controlling local flow (for faster cruise
speeds). Check out...
http://www.cafefoundation.org/research.htm and go to the flow control articles.
Also, I fully agree that any time a mod is done to a plane that it be done
*very*
carefully and methodically. Fortunately the *careful* installation of VGs
offers fairly straightforward results (and is relatively low risk) though it can
lead to problems if pilots don't understand proper flight testing procedures
and what is happening to the flight characteristics as VG's allow the wing to
fly slower and at a higher angle of attack. For instance it is very possible
to get a wing to fly so slow that the pilot gets behind the power curve. This
can cause real problems if not anticipated. It's also important for the pilot
to understand that if the stall speed is lowered so is the Va (maneuvering)
speed therefore they need to compensate in rough air.
Thanks for the info John. Good stuff.
Joa
www.landshorter.com
++++++++++++++++++++++++++++++++++++++++++++++++
Hi Joa,
I understand your enthusiasm in trying to sell your product by circulating to
all
the Matronics lists but are you aware that the Europa wing is designed for
cruise speed laminar flow ? My understanding of VG's and laminar flow wings is
that they are incompatible. I think it would be wise for you first to conduct
an evaluation trial on a Europa and then, if it is succesful over the whole
flight
envelope, owners might be interested to see your results. Alternatively,
if you can obtain an endorsement from the wing designer, Don Dykins BSc, CEng,
FRAeS, I am sure that you would get a lot of interest from the Europa community.
In the meantime, I suggest that Europa owners are very cautious before they
start
changing the aerodynamics of a very sophisticated and carefully designed
aircraft
which I understand was fully flight tested and complies with the JAR 23
regulations. VG's could bite you with the law of unintended consequences.
Cheers, John
---------------------------------
|