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Old September 20th 07, 03:48 PM posted to rec.aviation.soaring
Gav Goudie
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Posts: 2
Default Pawnee Cooldown Procedures

This technique of increasing airspeed and reducing
throttle to maintain a constant RPM (noise) and safe
cooling is the simplest and in my opinion works on
all tugs.
Robins, Rallyes, Supermunks, Pawnees all come down
fast at about ~ 110kt using this method and if you
plan your profile properly you should hit downwind
at about 500ft, the speed will fall into the flap range
and the first time you need to touch the throttle will
be around the turn onto finals.

KISS indeed

Gav





At 15:00 17 September 2007, wrote:
The following has worked at Skylark North in Tehachapi
for around 30
years and was policy at Estrella when Horvath owned
it:

Upon release, smoothly increase airspeed to around
rough air redline
(120 mph, 100 kts indicated) while smoothly reducng
power to remain at
about 2400 RPM. Rich Benbrook, one of my mentors and
chief pilot at
Skylark for many years stated it succinctly: 'Make
the engine sound
the same going down as it did going up'. This power
setting is held
until in the pattern where the power is slowly reduced,
the goal being
to be at flight idle and 70 mph over the fence. I
also never get out
of dead-stick glide range of the airport.

If you are in a hurry to get down, roll in full back
trim and maintain
whatever bank angle that gives you around 120 mph.
This is a lot of
g's to pull all day but it is effective.

The engines at Skylark routinely make TBO and they
experience no
cracked cylinders or other problems. We had a 260
hp Pawnee with CS
prop which added the complexity of managing the prop.
We slowly
reduced pitch while reducing the throttle. CS props
are not worth the
workload, cost or maintenaance issues, IMO.

Many schemes have been tested and ultimately abandoned
for this KISS
procedure that works.