C172 and Spins

Dan wrote:

I haven't flown a 140 in a long time -- are they still spinnable?

(There's one for sale locally)

Most are, as long as they don't have any heavy junk installed in the tail.


What did you do to get the airplane in a condition where the "C.G. is
up against the rear limit in the U.C?"

Seems to me if you were heading out to do spins you'd want no more
than two people (both up front), nothing loose in the airplane, and no
anvils in the baggage area.

Definitely empty rear seats and empty baggage. That's a condition of
operating in the Utility Category. In addition, there's a lower gross
weight limit, plus you have to adjust the fuel load to stay within the narrow
envelope. With 1 person on board and lots of fuel, it's possible to be right
at the rear limit of the envelope. The Utility Category C.G. envelope is
only 2.5 inches wide at 1650 lbs. and narrows to .7 inches wide at 1950 lbs.
(max weight for Utility Category).

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

--
Message posted via http://www.aviationkb.com

On Mar 20, 2:30 pm, "JGalban via AviationKB.com" u32749@uwe wrote:
Dan wrote:

I haven't flown a 140 in a long time -- are they still spinnable?

(There's one for sale locally)

Most are, as long as they don't have any heavy junk installed in the tail.



What did you do to get the airplane in a condition where the "C.G. is
up against the rear limit in the U.C?"

Seems to me if you were heading out to do spins you'd want no more
than two people (both up front), nothing loose in the airplane, and no
anvils in the baggage area.

Definitely empty rear seats and empty baggage. That's a condition of
operating in the Utility Category. In addition, there's a lower gross
weight limit, plus you have to adjust the fuel load to stay within the narrow
envelope. With 1 person on board and lots of fuel, it's possible to be right
at the rear limit of the envelope. The Utility Category C.G. envelope is
only 2.5 inches wide at 1650 lbs. and narrows to .7 inches wide at 1950 lbs.
(max weight for Utility Category).

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

--
Message posted viahttp://www.aviationkb.com

Yikes..

so fuel burn alters CG in flight?

(This is also a problem in the V tail Bonanzas).

Dan Mc

Dan wrote:
Yikes..

so fuel burn alters CG in flight?


The change is very slight and doesn't affect operation in the Normal
Category. The fuel tanks are just forward of the C.G. Fortunately, the C.G.
envelope gets wider as the weight goes down.

Not nearly as bad as the problem on the Bo, which could leave you outside
of the Normal Category envelope at the end of a long flight.

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

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...ation/200803/1

"Ken S. Tucker" wrote in
:

On Mar 18, 5:40 pm, Dan wrote:
On Mar 18, 8:57 pm, Roger wrote:

On Mon, 17 Mar 2008 18:38:38 -0400, Dudley Henriques

wrote:
Dan wrote:
Anyone else have expereince with the C172E (1964)?

No matter what I did I could not get that bird to spin to the
right.

Left spins take some work, and power helps (of course).

But right it just wallows and then steep spirals.

Dan Mc
Try accelerating the stall a bit just before reaching the 1g stall
point . Decelerate the airplane carrying just a bit of power into
the stall, then just before it would break naturally, apply
aggressive pitch, as the stall breaks, apply full pro-spin rudder.
It should break a lot cleaner and right into the spin; assuming
normal rigging.

Of course an extra bit of enthusiasm could lead to a snap roll.
:-)) Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)www.rogerhalstead.com

An enthusiastic Cross control stall has the same effect.

"Hey, I'm right side up!"
"Hey, I'm upside down!"

Now you're talking!
Do a 180 roll, then stall, and watch the heading
indicator do a fast 180, (The attitude indicator is
having a fit), as you recover from a spiral dive.
Most Flight Instructors are sissy pilots, that's
how I qualify them, by how much they shreak.

Good God. Those poor boys


Bertie

Dan wrote in news:ec7e887b-7eee-4bae-9805-
:

On Mar 20, 12:27 am, Dudley Henriques wrote:

I've never seen a snap roll develop from the spin entry input. The
controls are out of sequence; the timing is different; and the energy
state at initiation is not high enough to snap an airplane like a
172.

--
Dudley Henriques

I was thinking as I was reading your post "There's no way the 145 hp
172 is going to make it that far into that maneuver!"

These old 172 have too much surface, too little power.


Well, you can snap roll some gliders! not to well, but they'll do it.
Power has';t got a lot to do with it, though it's handy for keeping the
nose up a bit and increasing authority of the elevator and rudder.

Bertie

On Mar 20, 9:22 pm, Bertie the Bunyip wrote:

I was thinking as I was reading your post "There's no way the 145 hp
172 is going to make it that far into that maneuver!"

These old 172 have too much surface, too little power.

Well, you can snap roll some gliders! not to well, but they'll do it.
Power has';t got a lot to do with it, though it's handy for keeping the
nose up a bit and increasing authority of the elevator and rudder.

Bertie



True! I guess a nice steep dive will get all the energy needed....

But it's a borrowed 44 year old airplane, so we'll avoid those sorts
of things..

;-)

Dan Mc

Dan wrote in news:31e85801-4568-4ca1-9037-
:

On Mar 20, 9:22 pm, Bertie the Bunyip wrote:

I was thinking as I was reading your post "There's no way the 145
hp
172 is going to make it that far into that maneuver!"

These old 172 have too much surface, too little power.

Well, you can snap roll some gliders! not to well, but they'll do it.
Power has';t got a lot to do with it, though it's handy for keeping
the
nose up a bit and increasing authority of the elevator and rudder.

Bertie



True! I guess a nice steep dive will get all the energy needed....

But it's a borrowed 44 year old airplane, so we'll avoid those sorts
of things..


i've never snapped a 172. Why would you anyway? I would think it
wouldn;'t be all that good at it. 150s snap very well indeed. Nice clean
accurate exits are possible in them.


Bertie

On Mar 20, 9:53 pm, Bertie the Bunyip wrote:

i've never snapped a 172. Why would you anyway? I would think it
wouldn;'t be all that good at it. 150s snap very well indeed. Nice clean
accurate exits are possible in them.

Bertie

Don't want too, really -- that's a fairly violent maneuver for such a
stable airplane.

Is the 150 wing the same as the older 172s?

The 150 series certainly stall breaks cleaner, but I don't know if
that's due to CG or wing design.


Dan Mc

Dan wrote in news:c0af6cc3-fd00-43e1-bed9-
:

On Mar 20, 9:53 pm, Bertie the Bunyip wrote:

i've never snapped a 172. Why would you anyway? I would think it
wouldn;'t be all that good at it. 150s snap very well indeed. Nice
clean
accurate exits are possible in them.

Bertie

Don't want too, really -- that's a fairly violent maneuver for such a
stable airplane.

It's not the stability, it's the stress on the airframe. snaps are very
hard on airfames. Aside form the straight G, there's all srots of whip
loads on tail surfaces, fuselage, there's torsional loads in the wing,
etc.

Is the 150 wing the same as the older 172s?


Well, they're roughly the same planform, though the 150s surely must be
smaller overall. I think they both use an old fat NACA semi-symetrical.
In fact, I think Cessna only used one airfoil for all the strutted
pistons, so it would be CG and elevator authority that dicated it's
ability to do one. I'd say you could do it, but the chances of pulling
something off would be pretty good. At the very least I'd say you might
find some slightly stretched metal wing mounting parts if you looked
after doing a few snap rolls at a good speed.

The 150 series certainly stall breaks cleaner, but I don't know if
that's due to CG or wing design.

Proly CG and the relatively limited elevator available compared to the
150. Neither will stay in a spin very long, but the 172, I dont think
I've ever managed over a turn in any of them, and a half a turn is more
par for the course. The added power in a snap would probably aid in the
elevator department and allow a complete rotation, but I'm only
guessing.


Bertie

On Mar 20, 10:15 pm, Bertie the Bunyip wrote:

Well, they're roughly the same planform, though the 150s surely must be
smaller overall. I think they both use an old fat NACA semi-symetrical.
In fact, I think Cessna only used one airfoil for all the strutted
pistons, so it would be CG and elevator authority that dicated it's
ability to do one. I'd say you could do it, but the chances of pulling
something off would be pretty good. At the very least I'd say you might
find some slightly stretched metal wing mounting parts if you looked
after doing a few snap rolls at a good speed.

Well, that's certainly more than enough reason NOT to do that in this
172!


The 150 series certainly stall breaks cleaner, but I don't know if
that's due to CG or wing design.

Proly CG and the relatively limited elevator available compared to the
150. Neither will stay in a spin very long, but the 172, I dont think
I've ever managed over a turn in any of them, and a half a turn is more
par for the course. The added power in a snap would probably aid in the
elevator department and allow a complete rotation, but I'm only
guessing.

Bertie

The best spin wrung from the C172E (3 turns, tiny amount of residual
power going into the spin) was from a cross control stall to the left.
Full left rudder, full right aileron, full back elevator....

In a blink we were inverted, then into fairly nice high rotation rate,
low airspeed, very little pitch bobbing -- a by-the-book fully
developed spin.

Power off, full opposite rudder and simply release the back pressure
and the spin stopped.

Otherwise, you're right -- by turn 1 1/2 the 172 is pulling itself
into a steep spiral.


Dan Mc