Today's Message Index:
----------------------
1. 09:41 AM - prop strike (Richard Goode)
2. 09:51 AM - Re: prop strike (George Coy)
3. 03:13 PM - Re: Engine teardown after prop strike Questions (Jill Gernetzke)
4. 04:08 PM - Re: Engine teardown after prop strike Questions (Yak Pilot)
5. 04:12 PM - Re: Engine teardown after prop strike Questions (Yak Pilot)
Message 1
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I am not saying that an M 14 P should be completely stripped down if it has
a prop strike - I was merely pointing out that the original instruction came
from the engine designer and not from Termikas, who, like me, has a certain
vested interest in engine overhauling.
However, to make it clear, in Europe we do not automatically strip down any
engine that has had a prop strike - as has been pointed out there is a big
range of strikes which can have different results.
What we do, however, is to remove the gearbox, and check the crankshaft "run
- out". If it is less than 0.03 mm, we accept that the basic engine will be
fine, and in that case we simply crack test the gearbox components; overhaul
and then reassemble the gearbox and return the engine to service. The cost
of this is approximately $1800. It seems to me this is hardly a huge amount
for the peace of mind and safety implications.
On some occasions (very few) we find that the crankshaft "run - out" is more
than the accepted maximum (above), and in that case we perform a shock load
test on the entire engine.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Hereford
HR5 3LW
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
Message 2
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Some more thoughts
Dear Mr. Coy,
As regards the issue of inspection of the engine after a
propeller strike, we usually find that when propeller strike happens, the
main engine part that it is affected is the shaft that connects the
crankshaft with the accessories case across the supercharger (the part from
the next picture).
p1
About our experience on three cases from four propeller strikes, this shaft
was broken or twisted on the spline zones. We strongly recommend that this
item to be inspected at least, because this shaft drives all the engine
accessories (magnetos, fuel pump, oil pump, generator etc.). If this shaft
fails then the engine quits immediately.
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Richard Goode
Sent: Sunday, July 14, 2013 12:37 PM
Subject: Yak-List: prop strike
I am not saying that an M 14 P should be completely stripped down if it has
a prop strike - I was merely pointing out that the original instruction came
from the engine designer and not from Termikas, who, like me, has a certain
vested interest in engine overhauling.
However, to make it clear, in Europe we do not automatically strip down any
engine that has had a prop strike - as has been pointed out there is a big
range of strikes which can have different results.
What we do, however, is to remove the gearbox, and check the crankshaft "run
- out". If it is less than 0.03 mm, we accept that the basic engine will be
fine, and in that case we simply crack test the gearbox components; overhaul
and then reassemble the gearbox and return the engine to service. The cost
of this is approximately $1800. It seems to me this is hardly a huge amount
for the peace of mind and safety implications.
On some occasions (very few) we find that the crankshaft "run - out" is more
than the accepted maximum (above), and in that case we perform a shock load
test on the entire engine.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Hereford
HR5 3LW
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
Message 3
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| Subject: | Re: Engine teardown after prop strike Questions |
A clarification on my post. I was agreeing with Mark's reply to Roger's
post, not Richard's.
Jill
Message 4
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| Subject: | Re: Engine teardown after prop strike Questions |
George you are welcome to disagree.=C2- However your comments regarding t
he FAA are incorrect.=C2- I was investigated for 6 months regarding a pro
p strike that happened 6 years earlier.=C2- The FAA looked very hard for
documents just like the one mentioned so that they could say that I did imp
roper maintanence, violate me, and ground my airplane.=C2- I don't make t
his stuff up.=C2- After hiring a lawyer and spending thousands of dollars
, they decided my airplane was probably safe since it had flown 300 hours w
ith no problem since.=C2- My advice to this group is based on actual firs
t hand experience with the FAA, so readers can decide for themselves what t
he best course of action should be.=C2- My advice is not to hand the FAA
anything that can turn around and bite you in the ass later on.=C2- =0A
=C2-=0ADo what you will.=C2- I still have a very bad taste in my mouth.
=C2- =0A=C2-=0AMark=0A=C2-=0A=0A=0A________________________________
=0AFrom: George Coy <george.coy@gmail.com>=0ATo: yak-list@matronics.com =0A
Sent: Saturday, July 13, 2013 5:32 PM=0ASubject: RE: Yak-List: Engine teard
own after prop strike Questions=0A=0A=0A=0AMark, I disagree with you. I thi
nk people should have the facts and that includes factory recommendations.
As stated we are experimental, and not required to follow the factory recom
mendations on an experimental aircraft. The FAA is already well aware of th
e recommended overhaul times for eastern aircraft airframes and engines and
has never even questioned it in an experimental aircraft. Often, insurance
companies are driving the issue of teardown. Yes, I have flown many a Yak
that has had a prop strike and yes, yes I know of many aircraft hat have hu
ndreds of hours after a prop strike with no sign of damage. I have seen hid
den damage at a normal teardown that was waiting to become more serious.
=C2-So I think it is the owner/pilots decision and then should have all t
he information to make that decision. =0AGeorge Coy=0A=C2-=0AFrom:owner-y
ak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] O
n Behalf Of Bitterlich, Mark G CIV NAVAIR, WD=0ASent: Saturday, July 13, 20
13 2:33 PM=0ATo: yak-list@matronics.com=0ASubject: RE: Yak-List: Engine tea
rdown after prop strike Questions=0A=C2-=0ARichard- =0A=C2-=0AYour repl
y is a case in point for why I wrote what I did.=C2- The fact is that the
re are many types of prop strikes and the severity of the loads imposed to
the engine vary greatly.=C2- =0A=C2-=0AYou have stated many times how
=9Clucky=9D we in the West are regarding our Experimental Categ
ory and the ease by which we can license and operate our aircraft compared
to most operators in Europe.=C2- This is exactly the =9Cthing
=9D that I am trying to protect here and American owners need to take note.
=C2- =0A=C2-=0AThe FAA in the United States often likes to make things
simple by categorizing everything with some kind of =9Cwritten instru
ction=9D.=C2- If they can find a piece of paper that they can hold
close to their chest and demand compliance with, they often will.=C2- =0A
=C2-=0AYou said: =9CI personally think that far too many pilots in
the West are very casual about these engines after prop =93 strikes
=9D.=C2-=C2- =0A=C2-=0ARichard, you are welcome to any opinion
you wish to have, but please let=99s leave it at that.=C2-=C2- Wh
en you start to emphasize the validity of a posted document that happens to
agree with your point of view, and that document can possibly change the w
ay things are handled in another country,=C2- that crosses the line from
being an opinion to something else.=C2- I would ask that as a friend, you
at least keep that in mind.=C2- I know I do.=C2-=C2-=C2- =0A=C2-
=0AAs regards prop strikes on M-14 engines, I too believe in caution and sa
fety, but I also believe in applying common sense.=C2- I know of three M-
14 engines with =9Cprop strikes=9D that have flown over 600 hou
rs since the =9Cincident=9D without an issue.=C2- One of thos
e three =9CProp Strikes=9D was when an SU-31 prop hit a human l
eg and tossed the person it was attached to 10 feet in the air, and took a
huge chunk out of both his leg, and one prop blade of an MTV9-260!=C2- In
that case, the person=99s leg needed more of a teardown than the eng
ine did.=C2- But hey .... that was indeed a legitimate prop strike with b
lade damage.=C2-=C2-=C2- =0A=C2-=0ALots of things can damage an M-1
4, and I believe the most significant is some form of Hydraulic Lock.=C2-
I have seen far more M-14 engines come apart from this malady than prop st
rikes.=C2- =0A=C2-=0ASo bottom line. Let=99s continue to
have spirited and intense discussions, that include opinions and experienc
e, but please let=99s also try to avoid meddling in issues that can i
mpact how a whole class of engines or airplanes are treated in a country, e
specially ones that we don=99t live in.=C2- =0A=C2-=0AMark=0A=C2
-=0A=C2-=0Ahttp://www.matronics.com/Navigator?Yak-List=0Ahttp://forums.
=======
Message 5
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| Subject: | Re: Engine teardown after prop strike Questions |
Sorry to hear this Doc.=C2- My very best ....=0A=C2-=0AMark=0A=C2-=0A
=0A=0A________________________________=0AFrom: Roger Kemp M.D. <viperdoc@mi
ndspring.com>=0ATo: "yak-list@matronics.com" <yak-list@matronics.com> =0ASe
nt: Saturday, July 13, 2013 8:28 PM=0ASubject: Re: Yak-List: Engine teardow
n after prop strike Questions=0A=0A=0A=0AHad pitched out of the fight but w
ill re-enter. Since it is my rosy red pink being pulled behind that thing I
am tearing mine down. Yes the last gear up CJ's engine that I know of (M-1
4P with wood props) had no damage on tear down by Monty Barrett. Now saying
that the Builder in Lithuania rebuilt the engine with an out of spec maste
r crank roller bearings that were basically worn out. That was gotcha waiti
ng to happen. It was not Termikus's shop. That is all I will say. If the ow
ner of that engine wishes to comment he can.=C2-=0AAs for to tear or not
teardown, in the US we sort of have the option. Do I take 6 bullets out of
the revolver or do I take 5 to play Russian Roulette. It is our choice but
as George said, "insurance is driving the tear down requirement." If you ar
e self insured and like playing Roulette go for it. If you drop that bird i
n some one's house with others having knowledge of your flying with an engi
ne that had a prop strike that crapped out in flight causing injury on the
ground we are all going to pay. Your only hope is you got morted in the pro
cess so your estate can cover the loses.=0AWas there one of those in Maine
a couple of years ago or was a hydraulic lock that caused that one fall on
to the downtown streets morting both occupants.=C2-=0AMy two cents since
my insurance company is requiring =C2-the tear down, I'm tearing it down.
Would be a hell of a lot easier to repair the sheet metal, replace the lea
king air line, hang to new blades and go fly. But, right now I do not trust
that engine.=C2-=0ABreak, any one looking for a YAK -50 project? Will se
ll the airframe firewall back minus engine cheap. Contact me off list if in
terested. =C2-Will sell as is for salvage value or may consider parting i
t out.=C2-=0A=0ADoc=0A=0ASent from my iPad=0A=0AOn Jul 13, 2013, at 4:32
PM, "George Coy" <george.coy@gmail.com> wrote:=0A=0A=0AMark, I disagree wit
h you. I think people should have the facts and that includes factory recom
mendations. As stated we are experimental, and not required to follow the f
actory recommendations on an experimental aircraft. The FAA is already well
aware of the recommended overhaul times for eastern aircraft airframes and
engines and has never even questioned it in an experimental aircraft. Ofte
n, insurance companies are driving the issue of teardown. Yes, I have flown
many a Yak that has had a prop strike and yes, yes I know of many aircraft
hat have hundreds of hours after a prop strike with no sign of damage. I h
ave seen hidden damage at a normal teardown that was waiting to become more
serious. =C2-So I think it is the owner/pilots decision and then should
have all the information to make that decision. =0A>George Coy=0A>=C2-=0A
>From:owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@mat
ronics.com] On Behalf Of Bitterlich, Mark G CIV NAVAIR, WD=0A>Sent: Saturda
y, July 13, 2013 2:33 PM=0A>To: yak-list@matronics.com=0A>Subject: RE: Yak-
List: Engine teardown after prop strike Questions=0A>=C2-=0A>Richard- =0A
>=C2-=0A>Your reply is a case in point for why I wrote what I did.=C2-
The fact is that there are many types of prop strikes and the severity of t
he loads imposed to the engine vary greatly.=C2- =0A>=C2-=0A>You have s
tated many times how =9Clucky=9D we in the West are regarding o
ur Experimental Category and the ease by which we can license and operate o
ur aircraft compared to most operators in Europe.=C2- This is exactly the
=9Cthing=9D that I am trying to protect here and American owne
rs need to take note.=C2- =0A>=C2-=0A>The FAA in the United States ofte
n likes to make things simple by categorizing everything with some kind of
=9Cwritten instruction=9D.=C2- If they can find a piece of pa
per that they can hold close to their chest and demand compliance with, the
y often will.=C2- =0A>=C2-=0A>You said: =9CI personally think tha
t far too many pilots in the West are very casual about these engines after
prop =93 strikes=9D.=C2-=C2- =0A>=C2-=0A>Richard, you ar
e welcome to any opinion you wish to have, but please let=99s leave i
t at that.=C2-=C2- When you start to emphasize the validity of a posted
document that happens to agree with your point of view, and that document
can possibly change the way things are handled in another country,=C2- th
at crosses the line from being an opinion to something else.=C2- I would
ask that as a friend, you at least keep that in mind.=C2- I know I do.=C2
-=C2-=C2- =0A>=C2-=0A>As regards prop strikes on M-14 engines, I to
o believe in caution and safety, but I also believe in applying common sens
e.=C2- I know of three M-14 engines with =9Cprop strikes=9D t
hat have flown over 600 hours since the =9Cincident=9D without
an issue.=C2- One of those three =9CProp Strikes=9D was when
an SU-31 prop hit a human leg and tossed the person it was attached to 10 f
eet in the air, and took a huge chunk out of both his leg, and one prop bla
de of an MTV9-260!=C2- In that case, the person=99s leg needed more
of a teardown than the engine did.=C2- But hey .... that was indeed a le
gitimate prop strike with blade damage.=C2-=C2-=C2- =0A>=C2-=0A>Lot
s of things can damage an M-14, and I believe the most significant is some
form of Hydraulic Lock.=C2- I have seen far more M-14 engines come apart
from this malady than prop strikes.=C2- =0A>=C2-=0A>So bottom line
. Let=99s continue to have spirited and intense discussions, th
at include opinions and experience, but please let=99s also try to av
oid meddling in issues that can impact how a whole class of engines or airp
lanes are treated in a country, especially ones that we don=99t live
in.=C2- =0A>=C2-=0A>Mark=0A>=C2-=0A>=C2-=0A>http://www.matronics.co
m/Navigator?Yak-List=0A>http://forums.matronics.com/=0A>http://www.matronic
s.com/contribution=0A>=C2-=0A>==============
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ronics.com/Navigator?Yak-List==============
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