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  #11  
Old January 7th 05, 06:44 PM
Aaron Coolidge
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xyzzy wrote:
: What do you mean by a dog? Useful load, speed, what? What kind of TAS
: do you get in cruise? I'd be curious to hear this kind of feedback from
: 140 drivers, especially if they have also flown Warriors, 160s, or 180s
: and can give comparative experience.

Maybe I can help. I have a Cherokee 180 and have flown it 600+ hours. I have
also ferried a Cherokee 140 with the 160HP upgrade back & forth from MA to
FL a few times. I've also flown a Cherokee 140 with 150HP a couple times...

Real world figures with 36 year old airframes (the Cherokees all have METCO
wing tips, the Archer doesn't):
My Cherokee 180, no speed mods, Piper wheel pants, trues out at 141 MPH
at 70 ish % power.
The 160 HP Cherokee 140, no speed mods, Piper wheel pants, trues out at
117 MPH at 70 ish %. It has the AMRD prop tip mod.
The 150 HP Cherokee 140, no speed mods or wheel pants, trues out at
109 MPH at 70 ish %.
An Archer 2 (Old style wheel pants) owned by my friend (we fly in formation)
uses 50 less RPM to get the same TAS as I do.

Climb:
With 1 or 2 people and full fuel I rarely see less than 800 FPM initial
climb in my airplane. I usually see more like 1200 FPM. With the cold
weather, of course, climb performance is even better. In the summer at
gross wt (2400 lbs) I'll see at least 500 FPM.
The 150 HP Cherokee rarely makes 700 FPM, even in the winter. 500 FPM
in the summer is also unusual. (This plane has a tired engine, though.)
The 160 HP Cherokee is a solid 500+ FPM climb in the summer, 2 people and
36 gals of fuel. I haven't flown it in the dead of winter.

Thoughts: The big triangular hole under the Cherokee 140 cowling for
the cooling air exhaust is a tremendous source of drag. I would guess that
the fiberglass cowling on my airplane is the source of most of the speed
change between the 140 and the 180 airplanes. 20 extra HP just shouldn't
change the speed that much. The 20 extra HP also shouldn't make that much
difference in climb performance; I suspect that the much wider chord
prop on the 180 makes a big difference at low speeds. The 180 prop pitch
is also a climb prop pitch, and it can't be changed - it will easily make
redline RPM at any altitude I've flown at. Both 140 aircraft have cruise
props though I don't know the details.

I'd be happy to arrange a demonstration if anyone's in the area.
--
Aaron C. (N9376J)