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A fast servo driven trim tab on the rudder driven
by a solid state rate gyro from the model helicopter industry may do the
trick.
Wolfgang
----- Original Message -----
Sent: Saturday, July 02, 2011 1:23
AM
Subject: Re: [LML] Re: Ventral Strakes,
do they reduce performance?
I second Jeff's comment that a yaw damper is not really necessary
on the LIV P. Although it would be an improvement for a LIV PT. A true high
frequency yaw damper that did not move the rudder petals would improve the
ride in turbulence but none are available for GA.
Jack
Webb
L360, LIV
AeroSpace
Engineer BSAE
FAA Designated Check airman for C421, C404 &
C310
ATP, CFI Airplanes & Instruments, Multi, & Sea
Numerous Jet
Type Ratings
Experienced Experimental Test Pilot both multi and single
engine aircraft
Former Chief Engineering Test Pilot for a Major
Manufacturer
Ohio
From: "vtailjeff@aol.com"
<vtailjeff@aol.com>
To:
lml@lancaironline.net
Sent:
Friday, July 1, 2011 7:45 AM
Subject: [LML] Re: Ventral Strakes, do
they reduce performance?
You do not need a yaw damper in the IVP.
Jeff
Sent from my iPad
Hi Jack
Thanks for the explanations, I have the Tru-Trak sorcerer
installed in my plane and was planning the Yaw damper as it is said that the
4p changes yaw with every speed change, so I am assuming the yaw damper
together with the auto trim would correct this issue, right?
== Ronald
Ron,
Sorry it has taken so long but I have been
busy. You have asked several questions, and on the question of Ventral fins,
I have had installed Ventral fins on several LIV's. The need is much greater
for the LIV-PT but there is an improvement in both piston and turbine
models. The little dual fins are not as effective as one larger single fin.
Plus the drag seems to be lower. I have designed a single fin shape that
works well, no noticeable impact on cruise speed.
I did notice a slight speed reduction with the twin Ventral fin
taht are used on several LIV-PT's.
Clark Still's aircraft is a good example of a PT with the single
fin Ventral fin, on that airplane we made a very significant improvement in
directional stability.
On the question about yaw dampers, the
yaw damper is very helpful when it is a high frequency unit with no feedback
in the rudders. Unfortunately hte yaw dampers available currently are on
limited value plus the current units that connect directly to the rudder
increase the rudder friction band significantly making the airplane more
difficult to master yaw control. The ideal installation would a unit
operating a separate control surface such as the trailing edge of the
ventral fin.
Jack
Webb
L360, LIV
AeroSpace
Engineer BSAE
FAA Designated Check airman for C421, C404 &
C310
ATP, CFI Airplanes & Instruments, Multi, & Sea
Numerous
Jet Type Ratings
Experienced Experimental Test Pilot both multi and
single engine aircraft
Former Chief Engineering Test Pilot for a Major
Manufacturer
Corporate
Chief Pilot for Construction company
Ohio
Flying
is the perfect vocation for a man who wants to feel like a boy, but not for
one who still is.
From: RONALD STEVENS <ronald@sdc.com>
To: lml@lancaironline.net
Sent: Monday, June 27, 2011 7:34
AM
Subject: [LML] Ventral
Strakes, do they reduce performance?
Hello guys
Me again, I just had my first lesson with the Lancair 4p (with JC) and
when I took off the plane was wiggling its tail like a happy dog LOL Nothing
scary, but this I can imagine could be annoying for passengers.
Now I was looking on the internet and found that Ventral
Strakes were used to fight against those 'yaw' effects.
It suppose to help with turbulence, go-arrounds, full power take offs
as well.
My very near future plane (we are almost closing ;) is a newer one, so
the tail section was already updated to the latest.
But looking at my passengers (I fly with my Son and Girlfriend a lot)
this could be disturbing for them and I was already thinking of installing
the Yaw damper (I have the tru-trak sorcerer) and perhaps also installing
those Ventral strakes.
Does anybody have experience (before and after) with those? And would
you recommend those?
Thanks — Ronald Stevens (Cirrus 1100 hours, Velocity 250 hours, Lancair
4p student now with 1 hour
LOL)
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