Buying prop strike engine

Then you need to tear it down.????
If its a lycoming you need to tear it down regardless..... AD NOTE
joe




Michelle P wrote:
wrote:
http://www.whiteindustries.com/

White Industries lists engines with flange runout. What does flange
runout tell about the engine?

It seems some prop strike engines have a larger flange runout reading
than others, and the larger the flange runout, the lower the price.
Why?

Thanks.

The run out will tell you how badly the flange is bent. Thats it. In
order to tell how much damaged there was you need to know several
things: What was the power setting when the engine had it's strike?,
What kind of prop?, What did it hit? Was it a sudden stop or a slow down?
Then you need to tear it down. Throw away the crank. have the case
throughly inspected, have all of the other moving parts throughly inspected.

Personally I would only buy one as a core exchange if the manufacturer
will take it.

Michelle

Bret Ludwig wrote:
wrote:
Lou wrote:
If your going to rebuild anyway, take a look at these.
http://www.airboattrader.com/PartsForSale.htm


OK, if you're not going to buy a certiifed engine, then
what are the pros and cons of buying an airboat
engine vs a VW or Corvair conversion?


One, the airboaters are getting rid of the LyCon aircraft engines in
droves. That should tell you something.

Two, VWs are too small to be used as a direct drive airboat plant. A
direct drive VW is good only for motorgliders, drones, and the very
minimal single seat aircraft. Geared (or belted) VWs might be okay but
none are ever seen. Corvairs are proving crank breakers when operated
(direct drive) at power levels much over that of the old Pietenpol
conversions.

The stock VW cranks break too. 'Conversion' implies modification
which, at a minimum for VW and Corvair engines would include
replacing the crank. That doesn't address any other problems.


In my opinion there are only two ways to fly unless you have warbird
money: a certified aircraft engine in a certified airframe or a
homebuilt with an en-bloc-construction, liquid cooled general purpose
engine with belt or gear reduction. VWs, two strokes and the like are
just not powerful or dependable enough, noncertified "aircraft" designs
like the Jabiru are a worst of both worlds and vastly overpriced scam,
and LyCon aircraft engines are overpriced museum pieces if you don't
need a certificated engine.

Intersting, are there many en-bloc-construction, liquid cooled
general purpose engine powered homebuilts flying? (Aircampers
for one, right?).

--

FF

Runout is not a reliable indicator of damage. The prop may have
struck the surface more than once and bent the flange back from the
worse position it had been bent to on the first contact. Any bending
can crack a crank and the flange will dial OK; I've seen it on a couple
of O-200s we used to operate. I had an A-65 crank break in flight
between the first and second journals (rearmost and next ahead, the
farthest position from the prop) and I have read that these engines
tend to break at that spot after a prop strike. Flange runout, of
course, would have indicated nothing about the other end of the crank.
A propstrike also twists the whole crank (inertia) and cracks can
develop at the journal fillets; seen that, too. Runout readings won't
tell you everything about twist. The rest of the components, like rods,
pistons and gears, get shocked and will often show cracks or
deformation. Lycoming has an AD requiring teardown after any sudden
reduction in RPM, including contact with "grass, water or similar
yielding medium." Seems that the bolt that retains the crank gear on
its rear end comes loose and eventually the gear falls off. In flight,
of course. The camshaft and everything else stops turning.

Dan

Corvairs are proving crank breakers when operated
(direct drive) at power levels much over that of the old Pietenpol
conversions.

Flat out misleading, and shows that good 'ole Brett did not take the time to
read the whole story from William Wynne.

There are many factors that contribute to the Corvair crank breaks, but a
couple are using too long of a crank extension, using too heavy of a prop,
and using small props turning too many RPM's on very fast, slick aircraft.

If a person is really to want the whole, truthful story, it would be wise to
go to William's site, and read the whole story for yourself. Don't take
someone else's word on it, and especially not Brett's.

Sorry I had to respond to you, fredfighter, but I couldn't let that pass,
and I have Brett in the round file, where he belongs.
--
Jim in NC

joe wrote:
Then you need to tear it down.????
If its a lycoming you need to tear it down regardless..... AD NOTE
joe

It's only a service bulletin, not an AD.
Both Continental and Lycoming consider a teardown
mandatory after a prop strike.

no there is an AD note 2004 -10-14 i think that requires it

A few years back lycoming redefined what is a prop strike.....
A manufactururer SB does not make anything mandatory for a part 91
operator. An AD note does.......


Ron Natalie wrote:
joe wrote:
Then you need to tear it down.????
If its a lycoming you need to tear it down regardless..... AD NOTE
joe

It's only a service bulletin, not an AD.
Both Continental and Lycoming consider a teardown
mandatory after a prop strike.

joe wrote:
no there is an AD note 2004 -10-14 i think that requires it

A few years back lycoming redefined what is a prop strike.....
A manufactururer SB does not make anything mandatory for a part 91
operator. An AD note does.......


Ron Natalie wrote:

joe wrote:

Then you need to tear it down.????
If its a lycoming you need to tear it down regardless..... AD NOTE
joe


It's only a service bulletin, not an AD.
Both Continental and Lycoming consider a teardown
mandatory after a prop strike.


Read the Lycoming AD/SB carefully. Just because you hit something does
not mean you have to do a tear down.

Michelle A&P (having read the thing more than once in the last year)

abripl wrote:
1: The prop strike was with a wooden prop or...

Some composite props, like IVO, break easy on impact. I had a prop
strike with IVO and had the crank magnafluxed. No flange runout or
cracks were found. I have a Franklin 6A350 engine (are they more
solid?).. It's the aluminum rigid props that are crank killers.

You're taking your chances either way. A few years ago I met a guy
at a Montana backcountry strip that was taking his wings off and
putting his Champ on a flatbed truck. Seems his crank snapped in
flight and he was lucky enough to be within gliding distance of a
usable strip. He had taxied his plane into a snowbank a few months
earlier. It stopped the engine, but hadn't damaged the prop, so he
assumed everything was OK. That assumption nearly killed him and his
passenger a few months later.

Prop damage or flange runout doesn't tell you anything about possible
cracks in the crank.

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

If he hadn't run into the snow bank is there a guarantee that the crank
was OK? Aren't there faulty cranks for other reasons and it could have
been a coincidence? Also did he have an aluminum prop?

...............................Seems his crank snapped in
flight and he was lucky enough to be within gliding distance of a
usable strip. He had taxied his plane into a snowbank a few months
earlier. It stopped the engine, but hadn't damaged the prop, so he
assumed everything was OK. That assumption nearly killed him and his
passenger a few months later.
...

Morgans wrote:
Corvairs are proving crank breakers when operated
(direct drive) at power levels much over that of the old Pietenpol
conversions.

Flat out misleading, and shows that good 'ole Brett did not take the time to
read the whole story from William Wynne.

There are many factors that contribute to the Corvair crank breaks, but a
couple are using too long of a crank extension, using too heavy of a prop,
and using small props turning too many RPM's on very fast, slick aircraft.

If a person is really to want the whole, truthful story, it would be wise to
go to William's site, and read the whole story for yourself. Don't take
someone else's word on it, and especially not Brett's.


I don't claim to be an authority on corvairs or on any other engine. I
suggest that the authority on general purpose engines is their
designers and therefore one should endeavor to restrict all loads on
them to their design application. The marine guys, particularly
Kiekhafer with their I/O drives, should be studied long and hard.

Notice if you have a prop strike on a marine engine you don't
dismantle the engine. Why not? The drive takes those loads. Emulate
that.