Today's Message Index:
----------------------
1. 11:51 AM - Re: Yak-50 Electrical System Troubleshooting (Rob Rowe)
2. 12:46 PM - Re: Yak-50 Electrical System Troubleshooting (Scooter)
3. 06:04 PM - Re: Re: Scraping the T-3A Firefly... (Shinden33)
4. 06:52 PM - Re: Yak-50 Electrical System Troubleshooting (Rob Rowe)
5. 07:14 PM - Re: Re: Yak-50 Electrical System Troubleshooting (Roger Kemp)
6. 07:15 PM - Re: Re: Yak-50 Electrical System Troubleshooting (Roger Kemp)
7. 07:41 PM - Re: Yak-50 Electrical System Troubleshooting (Rob Rowe)
8. 08:54 PM - Re: Re: Yak-50 Electrical System Troubleshooting (Roger Kemp)
Message 1
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
Hi Harry
First off I'd like to whole heartedly endorse Mark B's excellent advice on fault
finding ... if you're uncertain of what you're doing then find someone qualified.
However they will probably find a set of accurate circuit drawings invaluable ...
so I did a a little research into YAK-50s, courtesy of Russian Engineering
who are only a half hour drive away, which highlighted the following;
- real-world feedback suggests YAK-50 electrics vary in detail from machine to
machine & the schematics suggest an evolution of the DC power management in particular.
I think the DC power diagram kindly supplied by Doc is "early" in that
there does not appear to be any over-voltage protection [OVP] unit & the "controller
RK-1500R" / "filter SF-3000R" are not types fitted to other YAK52/55s
or SUs ... AFAIK). Doc - does your documentation have any date info?
- schematics dated 1979 show DC power components identical to a YAK-52 with an
A3P-1MB OVP unit (assume as -52s went into production they started to standardise
the fit)
- schematics dated 1982 show an A3P-A2 OVP the same as contemporary YAK/SUs (complete
with hand drawn amendments!)
I d like to have copies of these schematics made (with RE's permission) ... the
challenge lies in that they're probably 3rd imprints already & they're 2m x lm
sheets ... so difficult to scan or photograph, let alone make legible.
So ... before looking into this further what's the full construction number of
your -50 Harry?
Cheers, Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=61838#61838
Message 2
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Harry,
Could you clarify steps 6 through 8 again. I think the Yak-52 has two switches
per gear leg (gear up and gear down... i think). Does the 50 have a single
switch? Also, what is your current draw before you get the short?
Is this correct:
6. Left Gear Up/Right Gear Up - short
7. Left Gear Disconnected/Right Gear Up - no short
8. Left Gear Disconnected/Right Gear Down - short
"6. Friends manually held both landing gear position
squat switches in the "gear-up" position and turned
the electrical switches off with the same result --
Gear switch breaks to off after several seconds
7. Disconnected the left gear position squat switch
at the bus bar in the wing root by removing the lower
three of the four wires (I believe the top wire is for
pitot heat) and turned on the batt, inst and gear
switches -- GOT IT -- Same result as step 4 above --
Gear switch does not break, the elec system remains on
with a right gear down green light; I'm fuzzy on this
part, but I believe I did the push-to-test for the
annunciator lights and all worked EXCEPT the chip
light and over-G light
8. And then the plot thickens -- With the electrical
system on, manually depressed the RIGHT landing gear
squat switch -- The RIGHT gear down light went out and
the LEFT gear up light went on (hopefully a simple
crossed wire) AND got a 2.5 amp draw and the gear
switch broke to the off position after several seconds "
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=61851#61851
Message 3
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| Subject: | Re: Scraping the T-3A Firefly... |
--> Yak-List message posted by: "Shinden33" <shinden33@earthlink.net>
Another interesting note. Edwards did full spin/departure testing on the
T-3 and found no adverse recovery characteristics or unusual modes. As I
understand it, the T-3 spun just as predictably as a C-150.
S
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com]On Behalf Of Roger Kemp
Sent: Thursday, September 14, 2006 8:48 AM
Subject: RE: Yak-List: Re: Scraping the T-3A Firefly...
--> Yak-List message posted by: "Roger Kemp" <viperdoc@mindspring.com>
Bottom line..they just need to get the good ol' reliable YAK-52
(ok...ok..add a few of the bent wings too...CJ'S!). Just to give them the
experience of a slow snap roll!
Doc
> [Original Message]
> From: Scooter <yakk52@verizon.net>
> To: <yak-list@matronics.com>
> Date: 9/14/2006 9:14:53 AM
> Subject: Yak-List: Re: Scraping the T-3A Firefly...
>
> --> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
>
> I believe it is all composite...
>
> Here's the history:
>
> "The T-3A is the newest version of Slingsby Aviation's T-67 Firefly line
of military training aircraft. The prototype began flying in the summer of
1991, and the Air Force accepted delivery in February 1994. Of the total
fleet of 110 T-3s which originally cost $32 million, 57 were stationed with
the Air Force Academy's 557th Flying Training Squadron in Colorado Springs,
with another 53 with the 3rd Flying Training Squadron in Hondo, Texas.
Final assembly of the British-made T-3 was done in Hondo by Northrup
Grumman.
>
> The Air Education and Training Command at Randolph AFB announced on 12
October 1999 that the T-3A Firefly would be dropped by the Air Force, after
having been grounded for more than two years. In 1998 the Air Force
intiated the privately run Introductory Flight Training which uses private
flight schools to screen pilot candidates. The success of this program
persuaded the Air Force to drop the T-3 from service. The T-3 fleet was
grounded in July 1997, following an inexplicable engine failure in
Colorado. Three instructors and three students were killed in crashes since
the plane went into service in 1994. Two crashes were the result of pilot
error, while a third occurred because of a stall condition from which the
pilot was unable to recover. The predecessor T-41 had no fatal accidents in
30 years of flight, although the T-41 was incapable of performing the
aerobatics and spins that were the hallmark of the T-3. The T-3's engine
had failed 66 times at takeoff or landing, and!
> the Air Force grounded 57 of the planes on 10 occasions due to problems
with the engines, fuel systems and brakes."
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=61569#61569
>
>
Message 4
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
Hi Harry,
I've annotated the attached PDF file from a photo of the YAK-50 gear & instruments
circuits, as per the 01.10.1982 schematic.
The wiring nomenclature does not tie up with your description of the gear switch
wires ... but most of the symptoms you described (save for the inverter turning
on) suggest the lamp test relay"C10" is worth investigation by a qualified
engineer.
A brief word of caution ... my experience of YAK wiring diagrams is that occasionally
they contain typos and/or small wiring anomalies ... another reason to
seek professional assistance with fault finding.
This schematic has such an anomaly on the far right hand side marked with the hatched
red line & query mark ... don't think this is significant with your issues,
but worth noting.
Cheers, Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=61891#61891
Attachments:
http://forums.matronics.com//files/yak_50_electrical_circuits_151.pdf
Message 5
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Roger Kemp" <viperdoc@mindspring.com>
Rob,
There is not a date on the manual. I have another question. As I rotated
today, my Airspeed went to 0. My altimeter worked fine. I have a Dynon
hooked in series with the Russian Airspeed indicator. The Dynon went to 0
also. Landed using A/S from the GPS. Works!
Plan to pull the rubber hose of the A/S indicator at the T fitting to Dynon
and blow high press back through the system. Before I do that, I am going
to drop the inspection panel in the left wing root and drain any water out
of the system if any is in there? Any other suggestions?
Doc
> [Original Message]
> From: Rob Rowe <yak-list@robrowe.plus.com>
> To: <yak-list@matronics.com>
> Date: 9/15/2006 2:17:03 PM
> Subject: Yak-List: Re: Yak-50 Electrical System Troubleshooting
>
> --> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
>
> Hi Harry
>
> First off I'd like to whole heartedly endorse Mark B's excellent advice
on fault finding ... if you're uncertain of what you're doing then find
someone qualified.
>
> However they will probably find a set of accurate circuit drawings
invaluable ... so I did a a little research into YAK-50s, courtesy of
Russian Engineering who are only a half hour drive away, which highlighted
the following;
>
> - real-world feedback suggests YAK-50 electrics vary in detail from
machine to machine & the schematics suggest an evolution of the DC power
management in particular. I think the DC power diagram kindly supplied by
Doc is "early" in that there does not appear to be any over-voltage
protection [OVP] unit & the "controller RK-1500R" / "filter SF-3000R" are
not types fitted to other YAK52/55s or SUs ... AFAIK). Doc - does your
documentation have any date info?
>
> - schematics dated 1979 show DC power components identical to a YAK-52
with an A3P-1MB OVP unit (assume as -52s went into production they started
to standardise the fit)
>
> - schematics dated 1982 show an A3P-A2 OVP the same as contemporary
YAK/SUs (complete with hand drawn amendments!)
>
> I d like to have copies of these schematics made (with RE's permission)
... the challenge lies in that they're probably 3rd imprints already &
they're 2m x lm sheets ... so difficult to scan or photograph, let alone
make legible.
>
> So ... before looking into this further what's the full construction
number of your -50 Harry?
>
> Cheers, Rob
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=61838#61838
>
>
Message 6
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Roger Kemp" <viperdoc@mindspring.com>
Rob,
Can you forward a cc of the wiring diagram also. My 50 is a 78 model though.
Doc
> [Original Message]
> From: Rob Rowe <yak-list@robrowe.plus.com>
> To: <yak-list@matronics.com>
> Date: 9/15/2006 9:00:47 PM
> Subject: Yak-List: Re: Yak-50 Electrical System Troubleshooting
>
> --> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
>
> Hi Harry,
>
> I've annotated the attached PDF file from a photo of the YAK-50 gear &
instruments circuits, as per the 01.10.1982 schematic.
>
> The wiring nomenclature does not tie up with your description of the gear
switch wires ... but most of the symptoms you described (save for the
inverter turning on) suggest the lamp test relay"C10" is worth
investigation by a qualified engineer.
>
> A brief word of caution ... my experience of YAK wiring diagrams is that
occasionally they contain typos and/or small wiring anomalies ... another
reason to seek professional assistance with fault finding.
>
> This schematic has such an anomaly on the far right hand side marked with
the hatched red line & query mark ... don't think this is significant with
your issues, but worth noting.
>
> Cheers, Rob
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=61891#61891
>
>
> Attachments:
>
> http://forums.matronics.com//files/yak_50_electrical_circuits_151.pdf
>
>
Message 7
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
Hi Doc,
viperdoc(at)mindspring.co wrote:
>
> As I rotated today, my Airspeed went to 0. My altimeter worked fine.
>
FWIW - looks like your static source is ok, but your dynamic feed is blocked /
open to atmos ... given you've recently installed the Dynon guess that would be
a good place to start checking the plumbing.
Careful with blowing high pressure into the either the static or dynamic lines
(especially dynamic) without first double checking the instruments are disconnected
... could be expensive.
Re YAK-50 schematics - will email you the file shortly
Cheers, Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=61897#61897
Message 8
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| Subject: | Re: Yak-50 Electrical System Troubleshooting |
--> Yak-List message posted by: "Roger Kemp" <viperdoc@mindspring.com>
Thanks Rob. I plan to disconnect the dynamic (impact) line proximal to the
Dynon and the RU A/S indicator. That way they will be isolated from any
pressure applied to the impact line.
Doc
> [Original Message]
> From: Rob Rowe <yak-list@robrowe.plus.com>
> To: <yak-list@matronics.com>
> Date: 9/15/2006 9:48:54 PM
> Subject: Yak-List: Re: Yak-50 Electrical System Troubleshooting
>
> --> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
>
> Hi Doc,
>
>
> viperdoc(at)mindspring.co wrote:
> >
> > As I rotated today, my Airspeed went to 0. My altimeter worked fine.
> >
>
>
> FWIW - looks like your static source is ok, but your dynamic feed is
blocked / open to atmos ... given you've recently installed the Dynon guess
that would be a good place to start checking the plumbing.
>
> Careful with blowing high pressure into the either the static or dynamic
lines (especially dynamic) without first double checking the instruments
are disconnected ... could be expensive.
>
> Re YAK-50 schematics - will email you the file shortly
>
> Cheers, Rob
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=61897#61897
>
>
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