Chuck wrote:
: I'll bet Vaughn is right on this one. My '63 Cherokee 180 POH is all
: MPG instead of KPH. I thought that most companies had switched
: totally to KPH by about 1970, but I recently checked out in a '76
: Arrow and the POH on it was also full of MPG instead of KPH.

OK... I can't take it anymore. Unless I missed a meeting, the following are
common abbreviations:
MPH: Miles per hour. Generally assumed statute miles
KPH: Kilometers per hour. Generally not used in aviation AFAIK
MPG: Miles per gallon. Generally assumed to be statute miles.
KT: Knots. A.K.A Nautical miles per hour

The confusion of the OP is about units, so being sloppy in the explanation
doesn't help and adds to my confusion (which I didn't even know I had).

: Oh, and remember -- there are things that can be done to modify those
: stall speed numbers. Putting on newer design "Horner" style wing tips
: and stabilator tips will drop stall speed about three to five MPH.
: Vortex generators on the wing top just behind the leading edge can
: drop stall another MPH or two. Flap & aileron seals can make a
: difference. Fairings on the flap extension actuators help. Wing root
: seals/fairings help. Wheel pants are a BIG help. Etc...

: From my reading, you can actually get your stall speed down almost
: 10MPH by putting on every gizmo kit STC'ed for a Warrior. And at the
: same time, you'll be adding top end speed to the plane as you smooth
: out the airflow. Problem is -- you'll spend a fortune doing it !!!

For the record, the Art Mattison VG's on the Hershey-bar Cherokees does a
really good job of reducing the stall speed. My -180 used to be barely flyable at 60
mph IAS will full flaps. With the VG's (and light-medium loaded), it'll *fly* at
60mph no flaps. Hang it on the prop with full flaps and it doesn't stall until 45mph.

The wingtips help reduce the (already bad) sink of the PA-28's at slow
airspeeds, so it helps climb a bit. The wheel pants give a bit of speed.... 2-3mph on
the old style, 3-5 on the new.

-Cory


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************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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