Declared first emergency last week

On Sep 8, 10:42*pm, EventHorizon wrote:
There have been a lot of other interesting ideas my post generated:

1 - switch to one mag
2 - carb heat
3 - pulse mags on/off (but if prop stops windmilling you'll need to
restart, not good)
4 - mixture (which is what we did)

Any engine experts have a recommendation on which approach would be best?
Or a combination?

Event Horizon

a wrote in news:a0945182-fc81-4f28-81f3-
:



I remember watching WW1 airplanes flying at Old Rhinbeck (sp?) airport
in NY. Those had two engine settings -- full on or off, and power was
controlled by what an electical engineer might call pulse width
modulation -- switch the mags on and off as needed. I have no idea how
that would work in today's engines, but my instinct would have been to
reach for mags, not mixture. Your way worked, I'll remember that.

Not bein' a pilot (I just jump out of them), doesn't lean cause an EGT
rise? Isn't there some risk of overheating a valve or somesuch if you
take it too lean?

Morgans wrote:

"brian whatcott" wrote

There's one element that is very troubling: the cable break in the
middle. I am supposing that the bowden has triple internal helical
wires as low friction standoffs - and that repeated motion against a
wire cut the cable.

That shouldn't happen....

Unless the run is perfectly straight, any bend will flex the internal
cable each time it moves. Metal fatigue still happens, given enough time.

If a plane is flown twice a week for thirty years, there could be
30 X 52 X 2 X 5 cycles on the throttle - and that's a highball estimate.
16000 cycles should not fatigue a wire, should it?

Brian W

On Sep 9, 7:35*am, brian whatcott wrote:
Morgans wrote:

"brian whatcott" wrote

There's one element that is very troubling: the cable break in the
middle. I am supposing that the bowden has triple internal helical
wires as low friction standoffs - and that repeated motion against a
wire cut the cable.

That shouldn't happen....

Unless the run is perfectly straight, any bend will flex the internal
cable each time it moves. *Metal fatigue still happens, given enough time.

If a plane is flown twice a week for thirty years, there could be
30 X 52 X 2 X 5 cycles on the throttle - and that's a highball estimate.
16000 cycles should not fatigue a wire, should it?

Brian W

The cable failure I had was to carb heat on an old Mooney Ranger, and
the failure was right at the carb. Finding a serious rubbing point
within the cable run itself seems unlikely, but that is what happened
to the OP.

If a plane is flown twice a week for thirty years, there could be
30 X 52 X 2 X 5 cycles on the throttle - and that's a highball estimate.
16000 cycles should not fatigue a wire, should it?

We replaced our prop adjustment cable in the Pathfinder this year. It was
probably the original cable from 1974. It was getting stiffer and stiffer
over time.

Upon removal it was obvious that a few strands of the sheathing had broken,
and were scraping on the cable every time we moved the blue lever. How
this happened is a mystery, but after 25 years we figured it didn't owe us
anything. (Although it is a real SOB to change...)

The OP did a great job getting the plane down safely.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
Ercoupe N94856
www.AlexisParkInn.com
"Your Aviation Destination"

In article ,
Richard wrote:

Not bein' a pilot (I just jump out of them), doesn't lean cause an EGT
rise? Isn't there some risk of overheating a valve or somesuch if you
take it too lean?

You are describing 'not lean enough' aka rich of peak temps, or at
peak temps. Lean the mixture some more and things get cooler.

John
--
John Clear - http://www.clear-prop.org/

Richard schreef:

Not bein' a pilot (I just jump out of them), doesn't lean cause an EGT
rise? Isn't there some risk of overheating a valve or somesuch if you
take it too lean?

Leaning does cause a rise in EGT - up to a certain point, which is the
point we want because it means optimal combustion, thus minimum fuel
burn for the HP. Leaning any further will make the engine very
inefficient, even to the point where it stops.

On a sidenote, many engines (especially the US-type aircooled boxers)
rely on a bit of excess fuel for valve lubrication so we get recommended
to keep them on the rich side of the EGT peak.

On Sep 9, 11:20*am, jan olieslagers
wrote:
Richard schreef:



Not bein' a pilot (I just jump out of them), doesn't lean cause an EGT
rise? *Isn't there some risk of overheating a valve or somesuch if you
take it too lean?

Leaning does cause a rise in EGT - up to a certain point, which is the
point we want because it means optimal combustion, thus minimum fuel
burn for the HP. Leaning any further will make the engine very
inefficient, even to the point where it stops.

On a sidenote, many engines (especially the US-type aircooled boxers)
rely on a bit of excess fuel for valve lubrication so we get recommended
to keep them on the rich side of the EGT peak.

Thank you both for the information.

"jan olieslagers" wrote in message
...
Richard schreef:

Not bein' a pilot (I just jump out of them), doesn't lean cause an EGT
rise? Isn't there some risk of overheating a valve or somesuch if you
take it too lean?

Leaning does cause a rise in EGT - up to a certain point, which is the
point we want because it means optimal combustion, thus minimum fuel burn
for the HP. Leaning any further will make the engine very inefficient,
even to the point where it stops.

On a sidenote, many engines (especially the US-type aircooled boxers) rely
on a bit of excess fuel for valve lubrication so we get recommended to
keep them on the rich side of the EGT peak.

With the correct type of injectors (on injector equipped engines) they can
be leaned far past where lean valve lubrication is a problem. Without the
correct induction system, many engines will run too rough to allow leaning
into safe areas of lean operation.
--
Jim in NC

"Jay Honeck" wrote

We replaced our prop adjustment cable in the Pathfinder this year. It was
probably the original cable from 1974. It was getting stiffer and stiffer
over time.

Upon removal it was obvious that a few strands of the sheathing had
broken, and were scraping on the cable every time we moved the blue lever.
How this happened is a mystery, but after 25 years we figured it didn't
owe us anything. (Although it is a real SOB to change...)

Yep. Some things will not last forever, and cables are one of them. Once
they get enough age and use and age on them, switch them out, as part of a
good preventative maintenance program. After all, what good is keeping fuel
in the tank, airspeed under the wings, and a good running engine and
airframe, if you can't control the damn thing! g That is one important
piece of twisted up steel, going from your hand to the engine and prop.

The OP did a great job getting the plane down safely.

No argument from me on that point!
--
Jim in NC

Sounds like you handled the situation well, but it doesn't sound like
an "emergency". My understanding is that you declare an emergency
when you need assistance or clearance RIGHT NOW. In this case, you
weren't in any imminent danger; notifying the tower of the situation
so that they know you'd be unable to go around or taxi off the active
runway once you killed the engine should be sufficient. The AIM
differentiates between "emergency" and "urgency".

Actually, the same thing happened to me about 25 years ago. A cotter
pin fell out of the throttle linkage on my Taylorcraft. The throttle
stuck in a position where I couldn't _quite_ maintain altitude.
Fortunately, the descent angle I could maintain got me to the nearest
airport, and I controlled the glide by blipping the ignition (no
mixture control on those old A-65's).

Even had I been so inclined, can't declare an emergency in a no radio
airplane.

After pushing the airplane off the runway, I found the clevis pin
inside the cowling. A scrap of wire sufficed to replace the missing
cotter pin and get me back home.

-Dana
--
Black holes are where God is dividing by zero.