Today's Message Index:
----------------------
1. 01:06 AM - 59,60, 107 and compressor (Mark Jefferies YAK UK Ltd)
2. 04:10 AM - 28V-to-14V converters (Brian Lloyd)
3. 05:49 AM - Re: Yak 52 Service Bulletin 107 (Bob Fitzpatrick)
4. 06:38 AM - Re: Yak 52 Service Bulletin 107 (William Halverson)
5. 06:52 AM - Re: Yak 52 Service Bulletin 107 (Brian Lloyd)
6. 06:54 AM - Re: Yak 52 Service Bulletin 107 (Brian Lloyd)
7. 07:34 AM - Re: Yak 52 Service Bulletin 107 (A. Dennis Savarese)
8. 08:02 AM - Compressor (Barry Hancock)
9. 08:05 AM - Re: Yak 52 Service Bulletin 107 (A. Dennis Savarese)
10. 08:35 AM - Re: Compressor (A. Dennis Savarese)
11. 08:58 AM - Re: Yak 52 Service Bulletin 107 (Ernie)
12. 10:34 AM - Loose Hooker crotch strap in the Yak-55m (Coffey, John)
13. 12:22 PM - Re: Yak 52 Service Bulletin 107 (Ron)
14. 12:27 PM - Re: Yak 52 Service Bulletin 107 (Ron)
15. 04:20 PM - Re: Yak 52 Service Bulletin 107 (A. Dennis Savarese)
16. 04:24 PM - Re: Yak 52 Service Bulletin 107 (A. Dennis Savarese)
17. 08:47 PM - Let's re-examine wing and airframe fatigue life (Frank Haertlein)
Message 1
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| Subject: | 59,60, 107 and compressor |
--> Yak-List message posted by: "Mark Jefferies YAK UK Ltd" <mark@yakuk.com>
Much has been said on this issue but only one "poster" hit the nail on the head.
The 59, 60 and 107 were implemented to INCREASE the service life to 5000 hours.
Lets look at a simple overview.
take a bit of metal and bend it up to a limit, after a certain number of cycles
it will break, we all agree on that.
next double the thickness of that bit of metal and bend it to the same limit. It
will break but after many more cycles.
You can all hypostasise about the limit on your a/c etc but trust me the manufactures
have the raw data and the test facilities, they did not upgrade for the
fun of it, there was a reason.
If you read the directive, you will see that it should be implemented on all aircraft
within 3 weeks of the issue date of the directive.
Dennis Savarese is 100% correct.
regards to all Mark.
BTW, an easy way to see if the compressor drive is broken is put a surgical glove
over the filter and turn the prop. As for running the engine with UR finger
on the outlet I assume you have no health and safety regs in USA !! Also a good
way of checking for leaks, (cracks, banjo washer etc is to pressure the system
by attaching you ground pipes near to the PRV.
Message 2
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| Subject: | 28V-to-14V converters |
--> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
I have a pair of high-performance 28V-to-14V converters that I have taken out of
service on my boat. They accept 20-50 volts of input and output 13.6V at up to
25 amps. They can be operated in parallel to deliver up to 50A. Size is 6" x
4.7" x 14". I am asking $150 each for them.
If you need to operate 12V devices in your CJ or Yak, you are going to need
something like one of these.
--
Brian Lloyd 6501 Red Hook Plaza, Suite 201
brian@lloyd.com St. Thomas, VI 00802
+1.340.998.9447 - voice +1.360.838.9669 - fax
GMT-4
Message 3
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "Bob Fitzpatrick" <rmfitz@direcway.com>
Bill,
As i recall the attachment fitting on the crotch strap in the 52 is somewhat
unique so we sent it to Hooker when ordering the harness and they duplicated
the old strap length when it was sewn in. Great harness and good people to
work with, call them.
bob
----- Original Message -----
From: "William Halverson" <william@netpros.net>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: William Halverson <william@netpros.net>
>
> I was waiting for someone to take the bait ...
>
> Actually, my point [I'm the guy who made the post] was that given the
> safety record Dennis researched, I'd feel much safer in a YAK-52 - with
> or without the wing spar fix - with a 'chute on than I would in a C150.
> Probably watch how fast I was pulling G's if the spar wasn't fixed ...
>
> But then what the hell, I fly a Yak-55 upside down for fun ... and on
> that point [upside down flying] am I the only guy who thinks the Hooker
> harness needs an adjustment in Yaks? The crotch belt has too much
> length in it ... I can't figure out how to shorten it up enough ... any
> ideas greatly appreciated!
>
> Bill Halverson
>
> A. Dennis Savarese wrote:
>
> >--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
> >
> >Ok. I give up!
> >Dennis
> >
> >----- Original Message -----
> >From: "Cy Galley" <cgalley@qcbc.org>
> >To: <yak-list@matronics.com>
> >Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> >
> >>--> Yak-List message posted by: "Cy Galley" <cgalley@qcbc.org>
> >>
> >>Point is they don't have to as they are structurally sound.
> >>
> >>----- Original Message -----
> >>From: "William Halverson" <william@netpros.net>
> >>To: <yak-list@matronics.com>
> >>Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> >>
> >>>--> Yak-List message posted by: William Halverson <william@netpros.net>
> >>>
> >>>Of course the other thing is ... how many people driving C150/152's
> >>>routinely wear parachutes?
> >>>
> >>>;-)
> >>>
> >>>Bill
> >>>
> >>>
> >>>A. Dennis Savarese wrote:
> >>>
> >>>>--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
> >>>>
> >>>>FWIW, I have also just finished visiting the NTSB site and read each
and every YAK 52 accident on record. None occurred before 1996 and clearly
NONE were due to wing spar failures.
> >>>>
> >>>>On another note, when talking about primary trainers like the YAK 52,
I was just reading an auction ad for a few Cessna 152's and 172's. Some of
the 172's WHICH ARE STILL AIRWORTHY, had (ready for this) 17,000+ hours.
Yes, 17,000! Now given the fact that many (not all) 172's spent much of
their life as trainers, would anyone like to challenge the structural
integrity of a YAK 52 at 1000 hours or even 5000 hours with or without SB107
versus a 150/152 with an national average of around 8500 hours or a 172 with
17,000 hours? Which one would you have more confidence in it's structural
integrity?
> >>>>Dennis Savarese
> >>>>
>
>
Message 4
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: William Halverson <william@netpros.net>
Hi Bob -
Thanks for the advice ... good idea!
Bill
Bob Fitzpatrick wrote:
>--> Yak-List message posted by: "Bob Fitzpatrick" <rmfitz@direcway.com>
>
>Bill,
>As i recall the attachment fitting on the crotch strap in the 52 is somewhat
>unique so we sent it to Hooker when ordering the harness and they duplicated
>the old strap length when it was sewn in. Great harness and good people to
>work with, call them.
>bob
>-----
>
Message 5
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
A. Dennis Savarese wrote:
> a YAK 52 at 1000 hours or even 5000 hours with or without SB107 versus a
> 150/152 with an national average of around 8500 hours or a 172 with 17,000
> hours? Which one would you have more confidence in it's structural
> integrity?
Aluminum structures have a fatigue life which steel structures ususally don't
(it depends on the type of steel). As the load approaches the design limits the
fatigue life gets *much* shorter. I suspect that Yak-52s are driven closer to
their structural design limits more often and for longers periods of time than
are C-150s and C-172s.
Regardless, I doubt that Yak-52s are likely to start shedding wings any time soon.
--
Brian Lloyd 6501 Red Hook Plaza, Suite 201
brian@lloyd.com St. Thomas, VI 00802
+1.340.998.9447 - voice +1.360.838.9669 - fax
GMT-4
Message 6
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
A. Dennis Savarese wrote:
> --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
>
> Yes the 172 is not certified as aerobatic, but it is approved for certain
> aerobatic maneuvers while in the utility category, including spins. I
> wonder how many students got close to or even exceed the utility category g
> loading on the 172 of +4.4 positive and -1.6 (I may be slightly off on that
> one). Heck, some of the landings made on these airplanes probably exceeded
> the limits, particularly in the standard category with a +3.8 positive
> limit.
I spin the C-150 and C-172 with all my students. I doubt if it ever gets loaded
beyond about 2.5Gs.
--
Brian Lloyd 6501 Red Hook Plaza, Suite 201
brian@lloyd.com St. Thomas, VI 00802
+1.340.998.9447 - voice +1.360.838.9669 - fax
GMT-4
Message 7
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
OK.
----- Original Message -----
From: "Brian Lloyd" <brian@lloyd.com>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
>
> A. Dennis Savarese wrote:
> > --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
> >
> > Yes the 172 is not certified as aerobatic, but it is approved for
certain
> > aerobatic maneuvers while in the utility category, including spins. I
> > wonder how many students got close to or even exceed the utility
category g
> > loading on the 172 of +4.4 positive and -1.6 (I may be slightly off on
that
> > one). Heck, some of the landings made on these airplanes probably
exceeded
> > the limits, particularly in the standard category with a +3.8 positive
> > limit.
>
> I spin the C-150 and C-172 with all my students. I doubt if it ever gets
loaded
> beyond about 2.5Gs.
>
>
> --
>
> Brian Lloyd 6501 Red Hook Plaza, Suite 201
> brian@lloyd.com St. Thomas, VI 00802
> +1.340.998.9447 - voice +1.360.838.9669 - fax
> GMT-4
>
>
Message 8
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--> Yak-List message posted by: Barry Hancock <radialpower@cox.net>
Well, I certainly do not have the expertise of Dennis, but I did have
the same problem...
At this point I have R&R'd just about every component on a CJ. For me,
the two most frustrating jobs are the oil cooler lines and the
compressor.
On Thursday, May 22, 2003, at 11:58 PM, Dennis wrote:
> As a test, you can remove the flare nut fitting going into the snot
> bottle.
> Run the engine and put a finger over the end of the tube at the flare
> nut.
> If it's working, you will feel the air pumping out. If
> not, ..............
This is good, but you have not eliminated the line running from the
compressor to the snot valve. I would suggest simply putting the palm
of your hand over the compressor intake and have someone turn the prop.
If the compressor is working, it will leave circular indents in your
hand (from sucking your skin through the grate). If no suckie, you have
one of two problems.
a) your compressor has failed
b) your shear pins have done their job (I hate to say failed when they
did something good).
>
> Removing the compressor is not an easy task. Having the proper tools
> specifically designed for removal and installation of the compressor
> is a
> must. Contact George Coy for a tool kit that includes the tools for the
> compressor. Be prepared for a lot of frustration.
Without the proper tools, it will take you 4-6 hours to get it off (and
you still need to highly modify an 11mm wrench to get to some of the
nuts - just ask Jeff Linebaugh). Getting it back on will take you
slightly less time. But it's easily a 10 hour job without the right
tools. I agree with Dennis, get the proper tools. It will cut your
time at least in half, but more importantly you won't be cussing (as
much?) like a sailor and kicking your dog...
Cheers,
B
BTW, I'm off to unravel the legend of the Yak-52 accelerated spins
today...
Barry Hancock
Director of Operations
Red Stars, Inc.
949.300.5510
www.allredstar.com
"Communism - Lousy Politics, Great Airplanes"
Message 9
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
One has to understand and realize that most of the YAK 52's that have been
imported and will be imported have considerably low airframe times. Like
400, 500, 600 or 700 hours as an example. The aircraft that I will bring in
are zero time, airframe, engine and prop. Complete overhauls. I would
agree with your analogy in paragraph one of your email if the YAK 52 had an
equivalent number of airframe hours as a 150/152 and 172. But, using my own
personal airplane as the example, this airplane was imported with 505 hours
total time in 1996. It stopped flying in 1991. I know how I have flown it
and quite frankly, it's been babied compared to it's previous life. I have
owned the airplane almost 4 years now. The previous US owner flew it pretty
much just like l do. Given these facts, it is unlikely this airplane in 500
hours of flight time in 10 years of flying (humm, let's see, that's only
about 50 hours a year) in a former eastern block country was "driven closer
to their (its) structural design limits more often and for longer periods of
time than are C-150s and C-172s." compared to a 22 year old 152/172 with
8000 plus hours on it.
I completely agree with you about YAK 52's shedding wings anytime soon
though.
Dennis Savarese
----- Original Message -----
From: "Brian Lloyd" <brian@lloyd.com>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
>
> A. Dennis Savarese wrote:
> > a YAK 52 at 1000 hours or even 5000 hours with or without SB107 versus a
> > 150/152 with an national average of around 8500 hours or a 172 with
17,000
> > hours? Which one would you have more confidence in it's structural
> > integrity?
>
> Aluminum structures have a fatigue life which steel structures ususally
don't
> (it depends on the type of steel). As the load approaches the design
limits the
> fatigue life gets *much* shorter. I suspect that Yak-52s are driven
closer to
> their structural design limits more often and for longers periods of time
than
> are C-150s and C-172s.
>
> Regardless, I doubt that Yak-52s are likely to start shedding wings any
time soon.
>
> --
>
> Brian Lloyd 6501 Red Hook Plaza, Suite 201
> brian@lloyd.com St. Thomas, VI 00802
> +1.340.998.9447 - voice +1.360.838.9669 - fax
> GMT-4
>
>
Message 10
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--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
Mark Jefferies had a terrific suggestion to see if the compressor is
"compressing". Stretch a surgical glove over the air filter area and turn
the prop by hand. If the compressor is moving internally, it will suck the
remaining air out of the glove. If not, get your tools ready!
Dennis
----- Original Message -----
From: "Barry Hancock" <radialpower@cox.net>
Subject: Yak-List: Compressor
> --> Yak-List message posted by: Barry Hancock <radialpower@cox.net>
>
> Well, I certainly do not have the expertise of Dennis, but I did have
> the same problem...
>
> At this point I have R&R'd just about every component on a CJ. For me,
> the two most frustrating jobs are the oil cooler lines and the
> compressor.
>
> On Thursday, May 22, 2003, at 11:58 PM, Dennis wrote:
>
> > As a test, you can remove the flare nut fitting going into the snot
> > bottle.
> > Run the engine and put a finger over the end of the tube at the flare
> > nut.
> > If it's working, you will feel the air pumping out. If
> > not, ..............
>
> This is good, but you have not eliminated the line running from the
> compressor to the snot valve. I would suggest simply putting the palm
> of your hand over the compressor intake and have someone turn the prop.
> If the compressor is working, it will leave circular indents in your
> hand (from sucking your skin through the grate). If no suckie, you have
> one of two problems.
>
> a) your compressor has failed
> b) your shear pins have done their job (I hate to say failed when they
> did something good).
> >
> > Removing the compressor is not an easy task. Having the proper tools
> > specifically designed for removal and installation of the compressor
> > is a
> > must. Contact George Coy for a tool kit that includes the tools for the
> > compressor. Be prepared for a lot of frustration.
>
> Without the proper tools, it will take you 4-6 hours to get it off (and
> you still need to highly modify an 11mm wrench to get to some of the
> nuts - just ask Jeff Linebaugh). Getting it back on will take you
> slightly less time. But it's easily a 10 hour job without the right
> tools. I agree with Dennis, get the proper tools. It will cut your
> time at least in half, but more importantly you won't be cussing (as
> much?) like a sailor and kicking your dog...
>
> Cheers,
>
> B
>
> BTW, I'm off to unravel the legend of the Yak-52 accelerated spins
> today...
>
>
> Barry Hancock
> Director of Operations
> Red Stars, Inc.
> 949.300.5510
> www.allredstar.com
> "Communism - Lousy Politics, Great Airplanes"
>
>
Message 11
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "Ernie" <ernest.martinez@oracle.com>
How does one overhaul a spar???
Ernie
----- Original Message -----
From: "A. Dennis Savarese" <adsavar@gte.net>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
>
> One has to understand and realize that most of the YAK 52's that have been
> imported and will be imported have considerably low airframe times. Like
> 400, 500, 600 or 700 hours as an example. The aircraft that I will bring
in
> are zero time, airframe, engine and prop. Complete overhauls. I would
> agree with your analogy in paragraph one of your email if the YAK 52 had
an
> equivalent number of airframe hours as a 150/152 and 172. But, using my
own
> personal airplane as the example, this airplane was imported with 505
hours
> total time in 1996. It stopped flying in 1991. I know how I have flown
it
> and quite frankly, it's been babied compared to it's previous life. I
have
> owned the airplane almost 4 years now. The previous US owner flew it
pretty
> much just like l do. Given these facts, it is unlikely this airplane in
500
> hours of flight time in 10 years of flying (humm, let's see, that's only
> about 50 hours a year) in a former eastern block country was "driven
closer
> to their (its) structural design limits more often and for longer periods
of
> time than are C-150s and C-172s." compared to a 22 year old 152/172 with
> 8000 plus hours on it.
>
> I completely agree with you about YAK 52's shedding wings anytime soon
> though.
> Dennis Savarese
>
> ----- Original Message -----
> From: "Brian Lloyd" <brian@lloyd.com>
> To: <yak-list@matronics.com>
> Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>
>
> > --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
> >
> > A. Dennis Savarese wrote:
> > > a YAK 52 at 1000 hours or even 5000 hours with or without SB107 versus
a
> > > 150/152 with an national average of around 8500 hours or a 172 with
> 17,000
> > > hours? Which one would you have more confidence in it's structural
> > > integrity?
> >
> > Aluminum structures have a fatigue life which steel structures ususally
> don't
> > (it depends on the type of steel). As the load approaches the design
> limits the
> > fatigue life gets *much* shorter. I suspect that Yak-52s are driven
> closer to
> > their structural design limits more often and for longers periods of
time
> than
> > are C-150s and C-172s.
> >
> > Regardless, I doubt that Yak-52s are likely to start shedding wings any
> time soon.
> >
> > --
> >
> > Brian Lloyd 6501 Red Hook Plaza, Suite 201
> > brian@lloyd.com St. Thomas, VI 00802
> > +1.340.998.9447 - voice +1.360.838.9669 - fax
> > GMT-4
> >
> >
>
>
Message 12
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| Subject: | Loose Hooker crotch strap in the Yak-55m |
--> Yak-List message posted by: "Coffey, John" <john.coffey@attws.com>
Bill,
I've got a 7-point Hooker in my Yak. I had a similar problem with a
loose crotch strap but after tweaking the belt arrangement, it works
just fine now.
Here's what I did:
- I had Hooker put the ratchet on the TOP lap belt on the pilot's right
side. This makes the ratchet much easier to get to. (Hooker is really
good about doing stuff like this. They swapped things around with a one
day turn around FOR FREE.)
- The shoulder straps & the crotch strap now ALL attach to the top
(ratcheted) lap belt. (NOTE: make sure you put the crotch strap on the
lap buckle AFTER both shoulder straps. DO NOT put the crotch strap onto
the lap buckle BETWEEN the shoulder strap attachments--it's very
unlikely, but I understand that it can jam upon release if you assemble
it that way.
If you are trying to attach the crotch strap to the bottom lap belt, you
won't be able to get the crotch strap tight.
Hope that helps.
Cheers,
John Coffey
Yak-55m Lover
-----Original Message-----
From: William Halverson [mailto:william@netpros.net]
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
--> Yak-List message posted by: William Halverson <william@netpros.net>
I was waiting for someone to take the bait ...
Actually, my point [I'm the guy who made the post] was that given the
safety record Dennis researched, I'd feel much safer in a YAK-52 - with
or without the wing spar fix - with a 'chute on than I would in a C150.
Probably watch how fast I was pulling G's if the spar wasn't fixed ...
But then what the hell, I fly a Yak-55 upside down for fun ... and on
that point [upside down flying] am I the only guy who thinks the Hooker
harness needs an adjustment in Yaks? The crotch belt has too much
length in it ... I can't figure out how to shorten it up enough ... any
ideas greatly appreciated!
Bill Halverson
A. Dennis Savarese wrote:
>--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
>
>Ok. I give up!
>Dennis
>
>----- Original Message -----
>From: "Cy Galley" <cgalley@qcbc.org>
>To: <yak-list@matronics.com>
>Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>
>>--> Yak-List message posted by: "Cy Galley" <cgalley@qcbc.org>
>>
>>Point is they don't have to as they are structurally sound.
>>
>>----- Original Message -----
>>From: "William Halverson" <william@netpros.net>
>>To: <yak-list@matronics.com>
>>Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>>
>>>--> Yak-List message posted by: William Halverson
<william@netpros.net>
>>>
>>>Of course the other thing is ... how many people driving C150/152's
>>>routinely wear parachutes?
>>>
>>>;-)
>>>
>>>Bill
>>>
>>>
>>>A. Dennis Savarese wrote:
>>>
>>>>--> Yak-List message posted by: "A. Dennis Savarese"
<adsavar@gte.net>
>>>>
>>>>FWIW, I have also just finished visiting the NTSB site and read each
and every YAK 52 accident on record. None occurred before 1996 and
clearly NONE were due to wing spar failures.
>>>>
>>>>On another note, when talking about primary trainers like the YAK
52, I was just reading an auction ad for a few Cessna 152's and 172's.
Some of the 172's WHICH ARE STILL AIRWORTHY, had (ready for this)
17,000+ hours. Yes, 17,000! Now given the fact that many (not all)
172's spent much of their life as trainers, would anyone like to
challenge the structural integrity of a YAK 52 at 1000 hours or even
5000 hours with or without SB107 versus a 150/152 with an national
average of around 8500 hours or a 172 with 17,000 hours? Which one
would you have more confidence in it's structural integrity?
>>>>Dennis Savarese
>>>>
Message 13
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "Ron" <l39parts@hotmail.com>
How does one "zero time" an airframe? The only way I know is to replace all
of the sheet metal and the rivets that hold it together to eliminate the
effects of fatigue. Is there another way? What FAA document could I refer
to on zero timing an airframe?
I know a guy that imported a bunch of warbirds that he said were zero timed.
About a year later he imported some that he was saying were overhauled even
better than the first batch. These I presume have negative times in the
logbooks.
----- Original Message -----
From: "A. Dennis Savarese" <adsavar@gte.net>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
>
> One has to understand and realize that most of the YAK 52's that have been
> imported and will be imported have considerably low airframe times. Like
> 400, 500, 600 or 700 hours as an example. The aircraft that I will bring
in
> are zero time, airframe, engine and prop. Complete overhauls. I would
> agree with your analogy in paragraph one of your email if the YAK 52 had
an
> equivalent number of airframe hours as a 150/152 and 172. But, using my
own
> personal airplane as the example, this airplane was imported with 505
hours
> total time in 1996. It stopped flying in 1991. I know how I have flown
it
> and quite frankly, it's been babied compared to it's previous life. I
have
> owned the airplane almost 4 years now. The previous US owner flew it
pretty
> much just like l do. Given these facts, it is unlikely this airplane in
500
> hours of flight time in 10 years of flying (humm, let's see, that's only
> about 50 hours a year) in a former eastern block country was "driven
closer
> to their (its) structural design limits more often and for longer periods
of
> time than are C-150s and C-172s." compared to a 22 year old 152/172 with
> 8000 plus hours on it.
>
> I completely agree with you about YAK 52's shedding wings anytime soon
> though.
> Dennis Savarese
>
> ----- Original Message -----
> From: "Brian Lloyd" <brian@lloyd.com>
> To: <yak-list@matronics.com>
> Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>
>
> > --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
> >
> > A. Dennis Savarese wrote:
> > > a YAK 52 at 1000 hours or even 5000 hours with or without SB107 versus
a
> > > 150/152 with an national average of around 8500 hours or a 172 with
> 17,000
> > > hours? Which one would you have more confidence in it's structural
> > > integrity?
> >
> > Aluminum structures have a fatigue life which steel structures ususally
> don't
> > (it depends on the type of steel). As the load approaches the design
> limits the
> > fatigue life gets *much* shorter. I suspect that Yak-52s are driven
> closer to
> > their structural design limits more often and for longers periods of
time
> than
> > are C-150s and C-172s.
> >
> > Regardless, I doubt that Yak-52s are likely to start shedding wings any
> time soon.
> >
> > --
> >
> > Brian Lloyd 6501 Red Hook Plaza, Suite 201
> > brian@lloyd.com St. Thomas, VI 00802
> > +1.340.998.9447 - voice +1.360.838.9669 - fax
> > GMT-4
> >
> >
>
>
Message 14
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "Ron" <l39parts@hotmail.com>
Certified planes undergo drop testing to test their ability to tolerate
landings. The negative g number refers to flying stresses.
----- Original Message -----
From: "A. Dennis Savarese" <adsavar@gte.net>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
>
> OK.
>
> ----- Original Message -----
> From: "Brian Lloyd" <brian@lloyd.com>
> To: <yak-list@matronics.com>
> Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>
>
> > --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
> >
> > A. Dennis Savarese wrote:
> > > --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
> > >
> > > Yes the 172 is not certified as aerobatic, but it is approved for
> certain
> > > aerobatic maneuvers while in the utility category, including spins. I
> > > wonder how many students got close to or even exceed the utility
> category g
> > > loading on the 172 of +4.4 positive and -1.6 (I may be slightly off on
> that
> > > one). Heck, some of the landings made on these airplanes probably
> exceeded
> > > the limits, particularly in the standard category with a +3.8 positive
> > > limit.
> >
> > I spin the C-150 and C-172 with all my students. I doubt if it ever
gets
> loaded
> > beyond about 2.5Gs.
> >
> >
> > --
> >
> > Brian Lloyd 6501 Red Hook Plaza, Suite 201
> > brian@lloyd.com St. Thomas, VI 00802
> > +1.340.998.9447 - voice +1.360.838.9669 - fax
> > GMT-4
> >
> >
>
>
Message 15
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
My error. I should have said 0 SMOH.
Dennis
----- Original Message -----
From: "Ron" <l39parts@hotmail.com>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: "Ron" <l39parts@hotmail.com>
>
> How does one "zero time" an airframe? The only way I know is to replace
all
> of the sheet metal and the rivets that hold it together to eliminate the
> effects of fatigue. Is there another way? What FAA document could I
refer
> to on zero timing an airframe?
>
> I know a guy that imported a bunch of warbirds that he said were zero
timed.
> About a year later he imported some that he was saying were overhauled
even
> better than the first batch. These I presume have negative times in the
> logbooks.
>
> ----- Original Message -----
> From: "A. Dennis Savarese" <adsavar@gte.net>
> To: <yak-list@matronics.com>
> Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>
>
> > --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
> >
> > One has to understand and realize that most of the YAK 52's that have
been
> > imported and will be imported have considerably low airframe times.
Like
> > 400, 500, 600 or 700 hours as an example. The aircraft that I will
bring
> in
> > are zero time, airframe, engine and prop. Complete overhauls. I
would
> > agree with your analogy in paragraph one of your email if the YAK 52 had
> an
> > equivalent number of airframe hours as a 150/152 and 172. But, using my
> own
> > personal airplane as the example, this airplane was imported with 505
> hours
> > total time in 1996. It stopped flying in 1991. I know how I have flown
> it
> > and quite frankly, it's been babied compared to it's previous life. I
> have
> > owned the airplane almost 4 years now. The previous US owner flew it
> pretty
> > much just like l do. Given these facts, it is unlikely this airplane in
> 500
> > hours of flight time in 10 years of flying (humm, let's see, that's only
> > about 50 hours a year) in a former eastern block country was "driven
> closer
> > to their (its) structural design limits more often and for longer
periods
> of
> > time than are C-150s and C-172s." compared to a 22 year old 152/172 with
> > 8000 plus hours on it.
> >
> > I completely agree with you about YAK 52's shedding wings anytime soon
> > though.
> > Dennis Savarese
> >
> > ----- Original Message -----
> > From: "Brian Lloyd" <brian@lloyd.com>
> > To: <yak-list@matronics.com>
> > Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> >
> >
> > > --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
> > >
> > > A. Dennis Savarese wrote:
> > > > a YAK 52 at 1000 hours or even 5000 hours with or without SB107
versus
> a
> > > > 150/152 with an national average of around 8500 hours or a 172 with
> > 17,000
> > > > hours? Which one would you have more confidence in it's structural
> > > > integrity?
> > >
> > > Aluminum structures have a fatigue life which steel structures
ususally
> > don't
> > > (it depends on the type of steel). As the load approaches the design
> > limits the
> > > fatigue life gets *much* shorter. I suspect that Yak-52s are driven
> > closer to
> > > their structural design limits more often and for longers periods of
> time
> > than
> > > are C-150s and C-172s.
> > >
> > > Regardless, I doubt that Yak-52s are likely to start shedding wings
any
> > time soon.
> > >
> > > --
> > >
> > > Brian Lloyd 6501 Red Hook Plaza, Suite
201
> > > brian@lloyd.com St. Thomas, VI 00802
> > > +1.340.998.9447 - voice +1.360.838.9669 - fax
> > > GMT-4
> > >
> > >
> >
> >
>
>
Message 16
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| Subject: | Re: Yak 52 Service Bulletin 107 |
--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
OK.
----- Original Message -----
From: "Ron" <l39parts@hotmail.com>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: "Ron" <l39parts@hotmail.com>
>
> Certified planes undergo drop testing to test their ability to tolerate
> landings. The negative g number refers to flying stresses.
>
> ----- Original Message -----
> From: "A. Dennis Savarese" <adsavar@gte.net>
> To: <yak-list@matronics.com>
> Subject: Re: Yak-List: Yak 52 Service Bulletin 107
>
>
> > --> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
> >
> > OK.
> >
> > ----- Original Message -----
> > From: "Brian Lloyd" <brian@lloyd.com>
> > To: <yak-list@matronics.com>
> > Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> >
> >
> > > --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
> > >
> > > A. Dennis Savarese wrote:
> > > > --> Yak-List message posted by: "A. Dennis Savarese"
<adsavar@gte.net>
> > > >
> > > > Yes the 172 is not certified as aerobatic, but it is approved for
> > certain
> > > > aerobatic maneuvers while in the utility category, including spins.
I
> > > > wonder how many students got close to or even exceed the utility
> > category g
> > > > loading on the 172 of +4.4 positive and -1.6 (I may be slightly off
on
> > that
> > > > one). Heck, some of the landings made on these airplanes probably
> > exceeded
> > > > the limits, particularly in the standard category with a +3.8
positive
> > > > limit.
> > >
> > > I spin the C-150 and C-172 with all my students. I doubt if it ever
> gets
> > loaded
> > > beyond about 2.5Gs.
> > >
> > >
> > > --
> > >
> > > Brian Lloyd 6501 Red Hook Plaza, Suite
201
> > > brian@lloyd.com St. Thomas, VI 00802
> > > +1.340.998.9447 - voice +1.360.838.9669 - fax
> > > GMT-4
> > >
> > >
> >
> >
>
>
Message 17
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| Subject: | Let's re-examine wing and airframe fatigue life |
--> Yak-List message posted by: "Frank Haertlein" <yak52driver@earthlink.net>
Dennis;
If we are worried about YAK-52's shedding wings then you seriously have
to consider the weaker wings on the CJ-6 or most any other aircraft.
Judging from what I've read, CJ-6's should be grounded....that is they
usually have much higher airframe hours than YAK-52's. But then,
realistically, the CJ-6 wing is strong and the YAK-52 wing is stronger
yet so where the hell is this going?.
The 100% over design load margin engineered into the YAK-52 speaks to
it's superior strength. I might add that 100% over design is a standard
of strength seldom seen in Western aircraft. I can't imagine someone
pulling plus 7G and minus 5G every time they flew their aircraft. You'd
have to fly like a crazy maniac every time you flew to approach the
design service life of YAK-52 wings. Who do you know that flies like
that?
If you want to apply the benefits of a realistic engineering analysis on
the airframe life of your airplane you would need to quantify the number
and severity of "G" cycles the wings are subject to. Most any other
method of measuring wing fatigue life is a guess. Short of having a data
acquisition system logging "G" data every time you flew, wing fatigue
life is at best a conservative estimate. Most engineers will take the
worst case scenario and publish specifications for that scenario. This
"engineered scenario" has little relation to the reality of how we fly
our planes. Do we all slam and bang our airplanes around every flight?
That seems to me what you'd have to do to approach the design limits of
the airframe.
A more accurate approach to design service life would be to integrate a
data logging system into our aircraft that logs all "G" data for the
life of the aircraft. This data would serve as a cumulative meter of "G"
loading and thus would be much more accurate in estimating design
service life than a typical "conservative engineering estimate" could
ever hope to achieve. There is a severe disconnect between the realities
of our flying and engineering estimates (I would add that this estimate
is biased in favor of your spending more on possibly un-needed
upgrades). With the advent of glass cot pits and computers in aircraft,
quantifying airframe stresses would be an easily achievable goal and
thus once and for all eliminating the guess work on airframe life that
seems to work to our disadvantage.
Frank
N911OM
PS...... For now, I will continue to venture forth with the utmost of
confidence in the brute strength and railroad tie stiffness of the
YAK-52 wing.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of A. Dennis
Savarese
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
One has to understand and realize that most of the YAK 52's that have
been imported and will be imported have considerably low airframe times.
Like 400, 500, 600 or 700 hours as an example. The aircraft that I will
bring in
are zero time, airframe, engine and prop. Complete overhauls. I
would
agree with your analogy in paragraph one of your email if the YAK 52 had
an equivalent number of airframe hours as a 150/152 and 172. But, using
my own personal airplane as the example, this airplane was imported with
505 hours total time in 1996. It stopped flying in 1991. I know how I
have flown it and quite frankly, it's been babied compared to it's
previous life. I have owned the airplane almost 4 years now. The
previous US owner flew it pretty much just like l do. Given these
facts, it is unlikely this airplane in 500 hours of flight time in 10
years of flying (humm, let's see, that's only about 50 hours a year) in
a former eastern block country was "driven closer to their (its)
structural design limits more often and for longer periods of time than
are C-150s and C-172s." compared to a 22 year old 152/172 with 8000 plus
hours on it.
I completely agree with you about YAK 52's shedding wings anytime soon
though. Dennis Savarese
----- Original Message -----
From: "Brian Lloyd" <brian@lloyd.com>
Subject: Re: Yak-List: Yak 52 Service Bulletin 107
> --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
>
> A. Dennis Savarese wrote:
> > a YAK 52 at 1000 hours or even 5000 hours with or without SB107
> > versus a 150/152 with an national average of around 8500 hours or a
> > 172 with
17,000
> > hours? Which one would you have more confidence in it's structural
> > integrity?
>
> Aluminum structures have a fatigue life which steel structures
> ususally
don't
> (it depends on the type of steel). As the load approaches the design
limits the
> fatigue life gets *much* shorter. I suspect that Yak-52s are driven
closer to
> their structural design limits more often and for longers periods of
> time
than
> are C-150s and C-172s.
>
> Regardless, I doubt that Yak-52s are likely to start shedding wings
> any
time soon.
>
> --
>
> Brian Lloyd 6501 Red Hook Plaza, Suite
201
> brian@lloyd.com St. Thomas, VI 00802
> +1.340.998.9447 - voice +1.360.838.9669 - fax
> GMT-4
>
>
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