On Wed, 03 Jan 2007 20:35:48 -0400, Dave
wrote in
:


Was not quoting Art here, although he mentioned to me verbally that he
has used full back yoke to rotate, especially with the heavier
engined cherokees and the "full fuel, 2 heavy front seat Pilot/pax
and no baggage" situation....

So the forward CG required more aggressive elevator.

I had it well back, but have not hit the stop yet, and may never.

Apparently, if done to soon, the aircraft simply won't lift...

The aggressive application of elevator reduces airspeed below stall
speed I suppose.

Although having spoken to several about this mod, I was only
slightly prepared for the result..

Now, remember, it was cold, slight head wind, and I was light.

Brakes held , full RPM, and let go....

I was well in the air at the 500 ft marker..

That's impressive. The information here
http://www.planeandpilotmag.com/content/specs/2006/piper_cherokee140.html
indicates that 800' is the book value. That works out to about a 38%
performance increase.

The deck angle was ...umm... "interesting" .

You mean you should have been wearing a parachute to comply with
91.307(c)(2)? :-)

And the little Warrior just wanted to keep going up... no wobbles, no
stall warning, no buffeting, just the most rapid "up" I have ever
experienced with 150 horses...

Gap seals help too.

Over a year ago. I got an E-mail from a straight wing Cherokee pilot
who indicated that these two mods are " the FIRST ones to spend money
on " when it comes to the Cherokees. He said he lowered his stall
speed by 7 mph.

I was doing 45 deg "S" turns at 45 knts indicated (at altitude)
easily. Lots of protest from the horn, but solid, no buffeting....

Cherokees were designed with a laminar flow airfoil, but the rivets
and any chipped paint, bugs and irregularities tend to cause premature
airflow separation. Apparently the VGs overcome that to some extent.

We have it at 4 knot difference so far, maybe 5..

One of my partners frequents a 1600 ft strip near his parents home. We
thought the extra margin would be a good investment.

More testing to come.. Will post results here if anyone interested.

I'm interested. I'm planning on grading a runway on an 80 acre parcel
if my offer is accepted. This parcel only permits about a 1,500'
length with some tall oaks in a ravine at one end, so anything that
reduces takeoff ground run is going to be installed. I'm hoping to
find a nice PA28-236, so keep us posted.