Engine out practice

Matt Whiting wrote in
:

J.Kahn wrote:

It's not a problem when heating because the head expands faster than
the steel parts so the stress effects are reversed. This is why the
manufacturers have no problem with going from idle to full power as
soon as the engine will take it without stumbling. There is no such
thing as shock heating...

What about the aluminum piston in the steel cylinder?


That can happen too! But the clearances are cgrater ther than it would be
in a valve stem or head to cylinder seat.

Bertie

Steve Hix wrote:
In article ,
Matt Whiting wrote:

Steve Hix wrote:
In article ,
Matt Whiting wrote:

Steve Hix wrote:

So they went out one morning, got plenty of cushion between themselves
and the ground, set the 172 into a landing configuration with full
flaps, and slipped it.

It shook a bit and then went inverted on them. They recovered and came
back home.
Got to love those urban legends!
I was sitting at the FBO front desk when Lynn and Fred went out to see
what would happen, and was there when they returned about a half hour
later.

They told me then what had happened, and agreed that they weren't
inclined to try it again with our 172. They weren't sufficiently
interested to see if it was affected one way or another by changing
payload, CG location, etc.

Not an urban legend, sorry if that disappoints you.
I don't for a second believe that a slip with flaps turned them over. I
suspect they STALLED it and went inverted, but that wasn't due to a slip
with flaps.

Kewl. Believe whatever floats your boat.

They were both experienced CFIs, one with a good deal of A-26 and T-28
time. If they'd stalled it, I would think they'd said so.

Likewise, believe all of the urban legends you want.

Matt

On Fri, 19 Oct 2007 11:05:32 +0000 (UTC), Bertie the Bunyip
wrote:

Matt Whiting wrote in
:

J.Kahn wrote:

It's not a problem when heating because the head expands faster than
the steel parts so the stress effects are reversed. This is why the
manufacturers have no problem with going from idle to full power as
soon as the engine will take it without stumbling. There is no such
thing as shock heating...

What about the aluminum piston in the steel cylinder?


That can happen too! But the clearances are cgrater ther than it would be
in a valve stem or head to cylinder seat.

If we had that kind of piston to cylinder clearance in an automotive
engine we'd think it was worn out. :-)) At least in the "old days".

Roger (K8RI)


Bertie

"Roger (K8RI)" wrote in
:

On Fri, 19 Oct 2007 11:05:32 +0000 (UTC), Bertie the Bunyip
wrote:

Matt Whiting wrote in
:

J.Kahn wrote:

It's not a problem when heating because the head expands faster
than the steel parts so the stress effects are reversed. This is
why the manufacturers have no problem with going from idle to full
power as soon as the engine will take it without stumbling. There
is no such thing as shock heating...

What about the aluminum piston in the steel cylinder?


That can happen too! But the clearances are cgrater ther than it would
be in a valve stem or head to cylinder seat.

If we had that kind of piston to cylinder clearance in an automotive
engine we'd think it was worn out. :-)) At least in the "old days".



Yes, some air cooled engines have tapered bores (when cold) to allow for
different rates of expansion in cylinder base-to-head so that it's
perfectly cylindrical when up to temp, but i don't know of any aircraft
engines that have that feature.



Bertie

Steve Hix wrote:

Kewl. Believe whatever floats your boat.

They were both experienced CFIs, one with a good deal of A-26 and T-28
time. If they'd stalled it, I would think they'd said so.


Why belabor the painfully obvious?

In article ,
Matt Whiting wrote:

Steve Hix wrote:
In article ,
Matt Whiting wrote:

Steve Hix wrote:
In article ,
Matt Whiting wrote:

Steve Hix wrote:

So they went out one morning, got plenty of cushion between themselves
and the ground, set the 172 into a landing configuration with full
flaps, and slipped it.

It shook a bit and then went inverted on them. They recovered and came
back home.
Got to love those urban legends!
I was sitting at the FBO front desk when Lynn and Fred went out to see
what would happen, and was there when they returned about a half hour
later.

They told me then what had happened, and agreed that they weren't
inclined to try it again with our 172. They weren't sufficiently
interested to see if it was affected one way or another by changing
payload, CG location, etc.

Not an urban legend, sorry if that disappoints you.
I don't for a second believe that a slip with flaps turned them over.

On second take, agreed.

I suspect they STALLED it and went inverted, but that wasn't due to a slip
with flaps.

Or a stall, alone.

On first pass, I read it as either/or, rather than combination.

Kewl. Believe whatever floats your boat.

They were both experienced CFIs, one with a good deal of A-26 and T-28
time. If they'd stalled it, I would think they'd said so.

Likewise, believe all of the urban legends you want.

Look, it was 30+ years ago. I was barely paying attention at the time,
and not knowing where either are today, I can't very well ask them for
more information.

Did whatever happen result solely from slipping with full flaps? I
really doubt it, unless they were at some extreme weight/CG limit (both
of them being average size, probably not).

So yeah, they likely did something else at the time that carried things
further. Stall alone? Doubt it. Slip with full flaps alone. Doubt it.

I still wouldn't want to play with something against which the aircraft
is placarded, not without a lot of cushion.

As for urban legend, you looking at the wrong guy. Spent too much time
studying physics/chemistry, and working in systems engineering for that.
(And doubly skeptical of conspiracy nonsense.)

And I apologize for blowing you off earlier; it's been a series of bad
months at work (I avoided the layoff, not everyone else in the group
did), and working 6 1/2 day weeks for 10 to 14 hrs/day for the last
month hasn't helped. Mea culpa.

Meanwhile, in Dec. I take off for what's going to turn out to be the
better part of four weeks vacation (else I start losing what's
accumulated), and after 31 years, get back into flying.

I may end up being civil by then.

"Bertie the Bunyip" wrote

Yes, some air cooled engines have tapered bores (when cold) to allow for
different rates of expansion in cylinder base-to-head so that it's
perfectly cylindrical when up to temp, but i don't know of any aircraft
engines that have that feature.

Really? I thought that they did have a tighter bore at the top. I guess I
read wrong, or remember wrong.
--
Jim in NC

"Morgans" wrote in
:


"Bertie the Bunyip" wrote

Yes, some air cooled engines have tapered bores (when cold) to allow
for different rates of expansion in cylinder base-to-head so that
it's perfectly cylindrical when up to temp, but i don't know of any
aircraft engines that have that feature.

Really? I thought that they did have a tighter bore at the top. I
guess I read wrong, or remember wrong.

Maybe. I didn't know that they did. It would make sense if they did, all
right. I don't do machining. I just run my fingers over the pretty parts
when they come out of the machine shop!

Bertie

Steve Hix wrote:

And I apologize for blowing you off earlier; it's been a series of bad
months at work (I avoided the layoff, not everyone else in the group
did), and working 6 1/2 day weeks for 10 to 14 hrs/day for the last
month hasn't helped. Mea culpa.

Meanwhile, in Dec. I take off for what's going to turn out to be the
better part of four weeks vacation (else I start losing what's
accumulated), and after 31 years, get back into flying.

I may end up being civil by then.

Steve, don't sweat it. I enjoy a good debate and rarely take offense at
anything and certainly took no offense at your comments as they were
quite civil.

Cheers,
Matt

Yes, some air cooled engines have tapered bores (when cold) to allow
for different rates of expansion in cylinder base-to-head so that
it's perfectly cylindrical when up to temp, but i don't know of any
aircraft engines that have that feature.

Really? I thought that they did have a tighter bore at the top. I
guess I read wrong, or remember wrong.

Maybe. I didn't know that they did. It would make sense if they did, all
right. I don't do machining. I just run my fingers over the pretty parts
when they come out of the machine shop!

This ought to be an easy question for someone in the group. Surely, there
is someone that does do machining on engines that hangs out here, that would
know for sure.

Anyone?
--
Jim in NC