Prop Strikes

Consider also that a prop is an e=ADssential
non-redundant monolithic structure, which if aluminum, is ma=ADde of a

material (2024-T3) that has good tensile, but mediocre fract=ADure
toughness properties.

Lightplane props are universally made of 2025T6, according to my
Sensenich prop manual. 2024T3 is used mostly for aircraft skins. The
2025 lacks the manganese and magnesium of the 2024, but has silicon
that the 2024 doesn't have. The yield and tensile strengths of 2025T6
are a bit less than 2024T3, but the metal isn't as hard, likely
reducing crack tendencies somewhat. The copper is still present, making
the prop corrosion-prone, and in Canada, at least, we have to remove
the prop, strip it and inspect it for corrosion at least every five
years. Corrosion pits can be as bad as nicks for starting cracks.
Dan

Lightplane props are universally made of 2025T6,

The drawing I saw was 2024 (& I recalled T3) but it was not a Sensenich
drawing.

I never heard of 2025 before, though since they are a forged blank,
they could create any alloy........ I originally thought they used
2017.

Steve

I've see reports of a belly landing in a twin where the Pilot shut the
engines down on final and used the starters to turn the props
horizontal. Belly landing did not cause any prop or engine damage.

In fact bird was lifted and gear extended and locked down. FAA gave a
one time permit and bird was flown with gear down to home base for the
minor repair to gear and belly skin.

Big John
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On Thu, 27 Jan 2005 19:34:43 -0500, "steve"
wrote:

isnt it a given to have 2 prop strikes when you belly a twin?

"Dan Thompson" wrote in message
news
I had two prop strikes on a twin when the nose gear wouldn't come down and
I had to land on the mains. Will never forget the tick-tick-tick of the
prop tips on the concrete. Or the short rollout. Or the jaunty angle when
deplaning.

wrote in message
oups.com...
Anyone else here ever experience one? How did yours happen?
Mine have been ag related and hit ground, rocks, birds, and ?
Ever throw off a piece of the prop blade? I lost a piece during
climbout of a jungle strip in the Amazon in a C-185. Managed to dead
stick it back without any further damage but it took nearly two months
to get a replacement. IN the meantime, I used a field expedient and cut
off an equal amount from the other blade. We were about 200 miles from
civilization on the Rio Curaray.
Ah the fun old days....
Ol S&B

On Tue, 1 Feb 2005, Big John wrote:

I've see reports of a belly landing in a twin where the Pilot shut the
engines down on final and used the starters to turn the props
horizontal. Belly landing did not cause any prop or engine damage.

I've read of guys killing themselves & passengers that way, because they'd
never practiced engine-out landings, or because they got too slow trying
to stop the prop(s), and stalled on final. So whatever you plan to do,
just make sure you practice it safely before you have to do it for real.

-Dan

Dan
I'd like to think pilots would have the sense to do those things at
altitude? But, I've seen experienced pilots do dumb things from on the
ground all the way up to above FL 180.
Ol S&B

"Samuel Nella" wrote in message Under what circumstances does this happen?

Usually during hard landings, when the airframe flexes and the engine pylon
rocks backwards.

D.

Capt Doug
In the late 60's, a student of mine who bought a Lake Dealership had me
flying with him for his private certificate. We went to the factory
where I got a good checkout and gave my student a lot of dual in his
brand new LA-4. He had some problems landing on water and I told him he
needed to keep his wings level when he touched down on water. He didn't
pay that much attention apparently since one day he tried to do a
"short water" approach and touched down with his wing down. It tore off
the wing sponson, dug the wingtip into the water and cartwheeled the
airplane. After all was said and done, the engine pylon had buckled
over and the prop nearly cut the empanage in half. He survived the
crash with no more than a cut on his forehead and bruises. I
participated in the salvage of the aircraft at 40' depth in a lake in
Louisiana. After his impact, he called on 122.8...."Concordia Unicom
come in quick and I'm not kidding...." then the airplane sank. He was
able to walk off the wing onto a speedboat that had been pulling water
skiiers, tied a float onto the rear tiedown point just as the Lake
Amphibian rolled over and sank inverted. I'ved got photos around here
someplace....

Any nick or scratch. It's where stresses can concentrate at a point and
cause a major failure. They can be filed out so that they don't form sharp
angles and thus redistribute the stress over a wider area.

I had a small ding on the "back" of my prop (the side you see when you're
looking at the nose from in front of the plane). During an assisted annual,
I filed it out so that it's now a smooth "dent". It has no sharp corners or
edges now.

mike regish


Incidentally, what's a "stress riser?"

Rod Machado had a good article in Flight Training mag recently. He asked a
student how much the most expensive plane he would ever fly would cost.
After the student giving him prices of Lear jets and Citations Rod said
"Wrong. The most expensive plane you'll ever fly is about $1000-the cost of
the insurance deductable."

mike regish

"Dan Youngquist" wrote in message
hell.org...
On Tue, 1 Feb 2005, Big John wrote:

I've see reports of a belly landing in a twin where the Pilot shut the
engines down on final and used the starters to turn the props horizontal.
Belly landing did not cause any prop or engine damage.

I've read of guys killing themselves & passengers that way, because they'd
never practiced engine-out landings, or because they got too slow trying
to stop the prop(s), and stalled on final. So whatever you plan to do,
just make sure you practice it safely before you have to do it for real.

-Dan

On Sat, 19 Feb 2005 17:44:44 -0500, "mike regish"
wrote:

"Wrong. The most expensive plane you'll ever fly is about $1000-the cost of
the insurance deductable."

Well, that's a view, but it's not a very good one in my opinion. If
you pay a million dollars for an airplane, it costs a whole lot more
than the insurance deductible: for one thing, you must pay the
"opportunity cost" that that million dollars would have earned for
you, say $50,000 a year if it were invested in a stock index fund over
the years and returned a mere 5 percent in dividends and appreciation.

It's also bad economics to think that passing a cost to the insurance
company is getting rid of it altogether: you're in fact passing it to
all the people who carry insurance.




-- all the best, Dan Ford

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