Engine failure on final

"Larry Dighera" wrote in message
...

Do you think that drag caused by an idling engine (and propeller) is
increased or decreased when it is producing zero power instead of idle
power?

It's an interesting question.

http://naca.larc.nasa.gov/reports/1934/naca-report-464/

includes comparison of a stopped prop, feathered prop, windmilling prop,
windmilling prop attached to a dead engine, and a prop driven by an idling
engine.

At low speeds, the idling engine produces thrust, while at higher speeds (75
mph in the case of the experiment) it is almost indistinguishable from the
prop driving a dead engine.

Julian Scarfe

Recently, Larry Dighera posted:

On Sat, 22 Jan 2005 21:31:46 GMT, "Neil Gould"
wrote in

As I was taught, the point of flying safely is to always have a
viable option. So, I fly tight patterns and make power-off landings
as a rule. If I make it to the pattern, I can make it to a runway,
engine or no.

Truly? So when you're #5 in the pattern (which necessitates a
looooong, extended downwind leg) you just fly the pattern at 2,000'
then?

Of course not, one has to use common sense, for example, fly the
pattern slower rather than lower

So your aircraft is slow enough to permit you to remain within gliding
distance of the threshold at normal pattern altitude while four other
aircraft head cross country several miles from the runway? Doubtful.

Larry... be reasonable! Few are likely to assess the situation and insist
that they fly the pattern in an irresponsible manner (although, I've been
in the pattern with some of those "few", as well). There are times when I
find myself behind some folks in a Cessna flying a base leg 2 or 3 miles
out, and in such a situation, I don't cut them off. ;-) I'm only
pointing out that there are usually other options than just flying long
downwind patterns and relying on engine power to save your bacon, and
being practiced with those options is a Good Thing. And, I realize that if
you're flying into busy air space, you don't have the option to practice.
;-)

Neil

On Sat, 22 Jan 2005 11:28:26 -0700, Klein wrote:

I go to idle
abeam the numbers and fly a circular arc to touchdown. No flaps
(don't have any) in an Extra 300L. Drops like a rock. Holding 90 kts
to the flare retains plenty of energy for the flare. I'd probably do
it differently in a 172. ;-)

I'd love to try this, but I fear I couldn't see the runway in the arc.


-- all the best, Dan Ford

email (put Cubdriver in subject line)

Warbird's Forum: www.warbirdforum.com
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the blog: www.danford.net

On Sat, 22 Jan 2005 21:28:09 -0500, "Rob Montgomery"
wrote:

Not to pick nits... but... doesn't an idle engine put out some thrust?

I asked my friend/CFI about this. He reckoned that it netted out to
about zero, and that I probably wouldn't notice the difference.

The only time the plane ever moved when the engine was at idle was on
glare ice. Then it taxied so fast that the only way I could negotiate
the turns (race-track oval plowed out) was to switch to right magneto,
the one that shows the greater drop.


-- all the best, Dan Ford

email (put Cubdriver in subject line)

Warbird's Forum: www.warbirdforum.com
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the blog: www.danford.net

and that will often mean flying a little faster than that since you are
probably gliding upwind to a point on the ground, after discounting the
fact that you are probably far below gross. If you don't have a feel
for that speed, err on the high side if there is a wind.

Blueskies wrote:

Also, lower nose if necessary to get best glide speed...

In article ,
Cub Driver wrote:


I asked my friend/CFI about this. He reckoned that it netted out to
about zero, and that I probably wouldn't notice the difference.

There is thrust at idle, and it's enough to make a difference. Have you
CFI go up and make a true dead stick landing, he'll change his story.

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

In article . net,
"Hilton" wrote:


On the ground while taxiing, sure it does, just take your feet off the
brakes and away you go. At flying speed however, it (perhaps surprisingly)
causes drag.


But not as much drag as a windmilling propellor.

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

Nobody has mentioned that one of the reasons to avoid aiming for the numbers
and to plan your touchdown point to be at the 1/3 point of a std 3000'
training rwy is to allow a margin for an engine failure on short final.

When doing a round base to touchdown approach this will also allow you to
see the runway sooner. In the real world you may be connecting a round
approach with a short field landing and will have to identify the features
of the extended centerline to navigate by. Caution, there are many
opportunities for CFIT.

Combining this approach with a constant slip allows you to control your
decent rate. I found it useful to practice this maneuver with some power on
to provide better engine temperature management. If you do this you will be
set up just right for soft field practice, and will avoid the inevitable
small stumble that often happens when you advance the throttle on a cold
idling engine.

At a busy training airport this maneuver, combined with a request to ATC for
simulated engine failure exercise(when making downwind call) will allow you
to pass a slow or underpowered&heavier aircraft or one that seems to be on a
xc circuit. ATC is not allowed to suggest this to you but they will know
exactly what you are doing. I have spent many practice hours doing this
exercise on every circuit, if ATC is not able they will deny your request or
sometimes give you a spacing or call your base if there is another ac that
has not yet cleared the rwy.

Aircraft with tandem seating are nice for this approach because they look
the same right or left. Aircraft without flaps really like this approach
especially in real engine out practice as it gives you great control of
decent. You can't do it for real if you don't practice when its not..

Caution YMMV as always, seek qualified instruction, a high time taildragger
instructor is a good bet, avoid 231 hr. wonders.

Blue skies to all


"Cub Driver" wrote in message
...
On Sat, 22 Jan 2005 11:28:26 -0700, Klein wrote:

I go to idle
abeam the numbers and fly a circular arc to touchdown. No flaps
(don't have any) in an Extra 300L. Drops like a rock. Holding 90 kts
to the flare retains plenty of energy for the flare. I'd probably do
it differently in a 172. ;-)

I'd love to try this, but I fear I couldn't see the runway in the arc.


-- all the best, Dan Ford

email (put Cubdriver in subject line)

Warbird's Forum: www.warbirdforum.com
Piper Cub Forum: www.pipercubforum.com
the blog: www.danford.net

Now hang on. The types of aircraft most of us fly will never have a
'windmilling' prop.
The engine quits the prop stops !
and an idling engine will add to the 'gliding' distance

"george" wrote in message
oups.com...
Now hang on. The types of aircraft most of us fly will never have a
'windmilling' prop.
The engine quits the prop stops !
and an idling engine will add to the 'gliding' distance


Been there and you are wrong. Maybe dead wrong. The engine stops, the prop
windmills and the drag goes way up. In boats (sail) the rule of thumb is a
windmilling prop is equal in drag to a flat disc the same diameter as the
prop. Stop the prop and the boat speeds up. Don't suppose a fixed pitch
airplane prop is any different.