Club Membership: Getting for what one's wished

[Andrew Gideon]

I posted this to the mailing list for the club to which
I belong, and I thought people here might appreciate it too.

When I joined the club a few months ago, a major motivation was to learn
more about the "operations" side of aircraft. To my mind, this meant
maintenance. As a renter, that side of things - outside of required
inspections and such - was a black box to me. I hoped to learn more
participating in the club.

I'm a lucky fellow, I guess.

<A club 172> wouldn't start this morning. I got to watch it tugged to MD's
hanger, and peer over the shoulder of Tom as he looked at it "naked" (I
cannot remember the last time I looked closely at a plane sans cowling).

I learned that one wires the frame to the engine when trying to start
the engine with the cowling top off to prevent the frame from hitting
the spinner. I learned that there is a single "starter" magneto
(although I think I actually knew that already). I learned that the
engine won't start if something's amiss with the single starter magneto.

I learned that it might be something like "a wiring problem", or that it
might require replacement of the magneto. I learned that, when leaving
an airplane with maintenance, one doesn't use the cover or brakes, but
one does put the control lock into place.

I learned that airplanes look rather unhappy when left with maintenance
with the cowling off.

I also had the opportunity to call the person with a booking later today
to give him the Bad News. I didn't really have the full experience of
that, though, as I had to leave a message with his voicemail. I did
also send what I think was a "text message", just as a backup.

I'm getting what I said I wanted, right?

One of the notes I received in response was:

Welcome to the world of airplane (co)ownership.

- Andrew

[Tina Marie]

In article e.com>, Andrew Gideon wrote:
> <A club 172> wouldn't start this morning. I got to watch it tugged to MD's
> hanger, and peer over the shoulder of Tom as he looked at it "naked" (I
> cannot remember the last time I looked closely at a plane sans cowling).

Yet another reason airplanes are better then women:

When you own, you can look at your plane naked anytime as you want.

Tina Marie
--
http://www.tripacerdriver.com "...One of the main causes
of the fall of the Roman Empire was that, lacking zero, they had no way
to indicate successful termination of their C programs." (Robert Firth)

[G.R. Patterson III]

Tina Marie wrote:
>
> Yet another reason airplanes are better then women:
>
> When you own, you can look at your plane naked anytime as you want.

If you've been married long enough, this is true of women - you just don't want
to very often. (ducking & running).

George Patterson
A woman's perfect breakfast occurs when she's sitting at the table sipping
gourmet coffee while looking at pictures of her son on the cover of Sports
Illustrated, her daughter on the cover of Business Week, her boyfriend on
the cover of Playgirl, and her husband on the back of the milk carton.

[Andrew Gideon]

Tina Marie wrote:

> Yet another reason airplanes are better then women:
>
> When you own, you can look at your plane naked anytime as you want.

Since reading your message, I've done some testing. I'm afraid that I must
disagree with you.

However, I do owe you thanks for a very nice evening.

- Andrew

[Peter Dohm]

I am sure that there are airplanes still in service that have engine(s) with
impulse coupling one only one of two magnetos; but I doubt the wisdom due to
liability and real risk of injury.

The purpose of the impulse coupling is to retard the spark; the fact that it
will usually also "fire a weak mag" is only a beneficial side effect. It is
really a safety feature to assure that the engine will start forward rather than
backward--since "kicking back" tends to remove the starter drive or the
lineman's fingers!

Many, if not most, of the C-172s use a "dual magneto", which is really two
magnetos on a common drive assembly including a single impulse coupling which
retards both of the magnetos for starting. If the engine has two separate
magnetos with impulse couplings, you can frequently hear the distinctive double
click when the engine is spun over to start.

The POH is a good source for documentation on what was standard, and what was
available when your airplane was built. The depot manual for the engine is
another good source, and one which may shed some light on possible modifications
to alternate "dash numbers". If I had an engine with impulse coupling on one
mag, I would locate any necessary documentation and make DAMNED SURE it had dual
impulse coupling before it ran again.

If you are not sure, or believe that your particular engine has impulse coupling
on only one magneto; then DON'T EVEN THINK ABOUT HAND STARTING IT!

Peter

Andrew Gideon wrote:
>
> I posted this to the mailing list for the club to which
> I belong, and I thought people here might appreciate it too.
>
> When I joined the club a few months ago, a major motivation was to learn
> more about the "operations" side of aircraft. To my mind, this meant
> maintenance. As a renter, that side of things - outside of required
> inspections and such - was a black box to me. I hoped to learn more
> participating in the club.
>
> I'm a lucky fellow, I guess.
>
> <A club 172> wouldn't start this morning. I got to watch it tugged to MD's
> hanger, and peer over the shoulder of Tom as he looked at it "naked" (I
> cannot remember the last time I looked closely at a plane sans cowling).
>
> I learned that one wires the frame to the engine when trying to start
> the engine with the cowling top off to prevent the frame from hitting
> the spinner. I learned that there is a single "starter" magneto
> (although I think I actually knew that already). I learned that the
> engine won't start if something's amiss with the single starter magneto.
>
> I learned that it might be something like "a wiring problem", or that it
> might require replacement of the magneto. I learned that, when leaving
> an airplane with maintenance, one doesn't use the cover or brakes, but
> one does put the control lock into place.
>
> I learned that airplanes look rather unhappy when left with maintenance
> with the cowling off.
>
> I also had the opportunity to call the person with a booking later today
> to give him the Bad News. I didn't really have the full experience of
> that, though, as I had to leave a message with his voicemail. I did
> also send what I think was a "text message", just as a backup.
>
> I'm getting what I said I wanted, right?
>
> One of the notes I received in response was:
>
> Welcome to the world of airplane (co)ownership.
>
> - Andrew

[Paul Sengupta]

"Peter Dohm" > wrote in message
...
> I am sure that there are airplanes still in service that have engine(s)
with
> impulse coupling one only one of two magnetos; but I doubt the wisdom due
to
> liability and real risk of injury.

> If you are not sure, or believe that your particular engine has impulse
coupling
> on only one magneto; then DON'T EVEN THINK ABOUT HAND STARTING IT!

My plane ony has the impulse coupling on one mag. You don't start it on
BOTH,
you start it on the left mag, like the Cherokee 140 I used to fly. When the
engine
is running, you switch to both.

Paul

[Dave Butler]

Peter Dohm wrote:
> I am sure that there are airplanes still in service that have engine(s) with
> impulse coupling one only one of two magnetos; but I doubt the wisdom due to
> liability and real risk of injury.

I'm pretty sure most of the fleet has impulse couplings on one mag only.

>
> The purpose of the impulse coupling is to retard the spark; the fact that it
> will usually also "fire a weak mag" is only a beneficial side effect. It is
> really a safety feature to assure that the engine will start forward rather than
> backward--since "kicking back" tends to remove the starter drive or the
> lineman's fingers!

Not sure in what context the impulse coupling will "fire a weak mag". The
impulse coupling only comes into play at very low RPM, like cranking speeds.

>
> Many, if not most, of the C-172s use a "dual magneto", which is really two
> magnetos on a common drive assembly including a single impulse coupling which
> retards both of the magnetos for starting. If the engine has two separate
> magnetos with impulse couplings, you can frequently hear the distinctive double
> click when the engine is spun over to start.

I don't think "most" C172s have a dual magneto on a common shaft, but then I'm
not a Cessna owner, so what do I know. Maybe the "new" 172s have this
arrangement? I think "most" C172s have dual magnetos, each with its own drive
shaft, and with an impulse coupling on just one magneto.

>
> The POH is a good source for documentation on what was standard, and what was
> available when your airplane was built. The depot manual for the engine is
> another good source, and one which may shed some light on possible modifications
> to alternate "dash numbers". If I had an engine with impulse coupling on one
> mag, I would locate any necessary documentation and make DAMNED SURE it had dual
> impulse coupling before it ran again.

OK, I'm not aware of any STCs to convert to dual impulse couplings. Anyway I
wouldn't spend any money on one if it were available, but that's just me.

>
> If you are not sure, or believe that your particular engine has impulse coupling
> on only one magneto; then DON'T EVEN THINK ABOUT HAND STARTING IT!
>

Well, I seldom think about hand-starting it anyway, but having a single impulse
coupling doesn't enter my thinking on the subject.

Dave

Remove SHIRT to reply directly.

[gross_arrow]

Tina Marie > wrote in message >...
> In article e.com>, Andrew Gideon wrote:
> > <A club 172> wouldn't start this morning. I got to watch it tugged to MD's
> > hanger, and peer over the shoulder of Tom as he looked at it "naked" (I
> > cannot remember the last time I looked closely at a plane sans cowling).
>
> Yet another reason airplanes are better then women:
>
> When you own, you can look at your plane naked anytime as you want.
>
> Tina Marie



why would i want to be naked when i look at my plane?

g_a

[TripFarmer]

Too funny! :)


Trip

In article >,
says...
>
>Tina Marie > wrote in message
>...
>> In article e.com>, Andrew
Gideon wrote:
>> > <A club 172> wouldn't start this morning. I got to watch it tugged to
MD's
>> > hanger, and peer over the shoulder of Tom as he looked at it "naked"
(I
>> > cannot remember the last time I looked closely at a plane sans
cowling).
>>
>> Yet another reason airplanes are better then women:
>>
>> When you own, you can look at your plane naked anytime as you want.
>>
>> Tina Marie
>
>
>
>why would i want to be naked when i look at my plane?
>
>g_a

[John Galban]

Peter Dohm > wrote in message >...
> I am sure that there are airplanes still in service that have engine(s) with
> impulse coupling one only one of two magnetos; but I doubt the wisdom due to
> liability and real risk of injury.

What does a single impulse coupling have to do with liability and
the risk of injury? Most of the singles in the fleet have a single
impulse coupling on the left mag only.

>
> The purpose of the impulse coupling is to retard the spark; the fact that it
> will usually also "fire a weak mag" is only a beneficial side effect. It is
> really a safety feature to assure that the engine will start forward rather than
> backward--since "kicking back" tends to remove the starter drive or the
> lineman's fingers!

It's really a safety feature? That's a new one on me. As far as I
know, the impulse coupling retards the spark to enable the engine to
start at low rpm. It also gives the mag a quick "spin" to increase
the power of the spark. If you have no coupling, you get no start
(unless the plane is equipped with a "shower of sparks" system).

>
> Many, if not most, of the C-172s use a "dual magneto", which is really two
> magnetos on a common drive assembly including a single impulse coupling which
> retards both of the magnetos for starting. If the engine has two separate
> magnetos with impulse couplings, you can frequently hear the distinctive double
> click when the engine is spun over to start.

I wouldn't say that "most" C-172s are equipped with the dual
magneto. The ones that have it are noted by a "D" in the forth
position of the engine identifier (e.g. O-320-H2AD). Dual mags are
not that popular because they have a common point of failure. The
drive gear. This goes against the notion of having two redundant
ignition systems. They are not common in the fleet.

<snip>
>If I had an engine with impulse coupling on one
> mag, I would locate any necessary documentation and make DAMNED SURE it had dual
> impulse coupling before it ran again.

I don't understand. What makes dual impulse couplings safer. If
you have a single coupling and it fails, you get no start. The normal
spark timing is to far advanced and the mags are turning too slow to
provide a strong enough spark at the proper time.
>
> If you are not sure, or believe that your particular engine has impulse coupling
> on only one magneto; then DON'T EVEN THINK ABOUT HAND STARTING IT!

I must be missing something here. The only airplanes I've ever hand
started had a single coupling on the left mag. This is the most
common configuration for piston singles. Could you elaborate on why
you think this is dangerous?

John Galban=====>N4BQ (PA28-180)

[Ron Natalie]

"John Galban" > wrote in message m...

> What does a single impulse coupling have to do with liability and
> the risk of injury? Most of the singles in the fleet have a single
> impulse coupling on the left mag only.

And because impulse couplings fail. What's not there can't fail. That
argues for only having one (as opposed to the OP who wants two).

> It's really a safety feature? That's a new one on me. As far as I
> know, the impulse coupling retards the spark to enable the engine to
> start at low rpm. It also gives the mag a quick "spin" to increase
> the power of the spark. If you have no coupling, you get no start
> (unless the plane is equipped with a "shower of sparks" system).

You don't even have to have an impulse coupling, the coupling just gives
you a stronger spark (since the mags are pretty weak even when
turning at full speed). You may need this if you've got less than
optiumum conditions (like small amounts of plug foulilng).

[G.R. Patterson III]

Peter Dohm wrote:
>
> I am sure that there are airplanes still in service that have engine(s) with
> impulse coupling one only one of two magnetos;

Yep. For example, a brand new Maule MX-7-160.

George Patterson
To a pilot, altitude is like money - it is possible that having too much
could prove embarassing, but having too little is always fatal.