Today's Message Index:
----------------------
1. 04:51 AM - M14P limitations (Rob Rowe)
2. 06:06 AM - Re: M14P limitations (A. Dennis Savarese)
3. 09:45 AM - Roger Modglin (Duncan aka Russ)
4. 10:07 AM - M14P (Richard Goode)
5. 10:48 AM - Re: Max G Light (owner-yak-list-server@matronics.com)
6. 04:40 PM - Re: M14P limitations (Rob Rowe)
7. 09:59 PM - Rodger's Tribute (Terry Calloway)
Message 1
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| Subject: | M14P limitations |
--> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
Can anyone shed some light on the following engine limitations quoted in the
Yak-52/M14P Russlish manuals please?
1/ Does the M14P produce more then than 360hp when firewalled?
The M14P is quoted as producing 360hp at Take Off power (or as stated in
engine "passport" at manufacture), so does this mean it can produce slightly
more than this when firewalled?
Given that TO power is quoted as 125 mmHg over ambient (let's call it
760mmHG on an average day) is c.885 mmHG and I recall that I've seen a
little more than this when firewalled (at least at low level).
This makes allowance for a manifold gauge that's not been recalibrated since
1991 manufacture & reads a little high when cross-referenced (0.75 x
millibars = ~ mmHg) with the calibrated altimeter "ambient" pressure.
2/ Time limits
TO settings ... 125mmHg over ambient / 99% rpm (reducing by c.1% per 5C
below 15C) ... is permissible for 5 mins - understood.
However max rpm (101%) is quoted as being permitted for only 1 minute ...
but what settings or conditions would allow max rpm to be induced, other
than partial governor failure?
ie. is this containment of a temporary "fault" condition rather than a
"normal use" limitation? ... in much the same way as the 109% overspeed is
permissible for 1 second (30 minutes over engine life) eg. highly gyroscopic
aeros.
More over any thoughts on why a 2% RPM change (TO versus max rpm) should
have such a significant impact on the time limitations?
Is this a prop governor, rather than an engine, limitation perhaps?
All insight gratefully received ... I've some new guys in our Yak syndicate
who have spotted these apparent anomalies, so I'm trying to get some
definitive answers and a supporting explanation ... hence the detail!
Cheers, Rob
Message 2
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| Subject: | Re: M14P limitations |
--> Yak-List message posted by: "A. Dennis Savarese" <dsavarese@elmore.rr.com>
My reply is within your email in ALL CAPS.
Dennis
----- Original Message -----
From: "Rob Rowe" <yak-list@robrowe.plus.com>
Subject: Yak-List: M14P limitations
> --> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
>
> Can anyone shed some light on the following engine limitations quoted in
> the
> Yak-52/M14P Russlish manuals please?
>
> 1/ Does the M14P produce more then than 360hp when firewalled? YES, IT
> POSSIBLY CAN. JUST LIKE ANY INTERNAL COMBUSTION ENGINE, MANY FACTORS WILL
> DETERMINE MAXIMUM HORSEPOWER. ENGINE TIMING BEING ONE OF THEM.
>
> The M14P is quoted as producing 360hp at Take Off power (or as stated in
> engine "passport" at manufacture), so does this mean it can produce
> slightly
> more than this when firewalled? IT DEPENDS. SOME ENGINES ON THE DYNO
> PRODUCED A COUPLE OF HORSEPOWER MORE THAN 360 AND SOME A COUPLE OF
> HORSEPOWER LESS. AT 100% RPM ON TAKE OFF AT SEA LEVEL, THE AVERAGE ENGINE
> WILL PRODUCE 360HP.
>
> Given that TO power is quoted as 125 mmHg over ambient (let's call it
> 760mmHG on an average day) is c.885 mmHG and I recall that I've seen a
> little more than this when firewalled (at least at low level).
>
> This makes allowance for a manifold gauge that's not been recalibrated
> since
> 1991 manufacture & reads a little high when cross-referenced (0.75 x
> millibars = ~ mmHg) with the calibrated altimeter "ambient" pressure.
>
> 2/ Time limits
>
> TO settings ... 125mmHg over ambient / 99% rpm (reducing by c.1% per 5C
> below 15C) ... is permissible for 5 mins - understood.
>
> However max rpm (101%) is quoted as being permitted for only 1 minute ...
> but what settings or conditions would allow max rpm to be induced, other
> than partial governor failure? YOU ARE ASSUMING THE ACCURACY OF YOUR
> TACHOMETER IS BETTER THAN 1%. I AM GUESSING IT IS NOT. WITHOUT ANY
> FAILURES WHATSOEVER, THE PROP GOVERNOR CAN EASILY BE SET TO EXCEED 100%
> RPM (OR 2900 RPM) AS READ ON THE TACHOMETER. SIMPLY ADJUST THE STOP
> LIMIT.
>
> ie. is this containment of a temporary "fault" condition rather than a
> "normal use" limitation? ... in much the same way as the 109% overspeed is
> permissible for 1 second (30 minutes over engine life) eg. highly
> gyroscopic
> aeros.
>
> More over any thoughts on why a 2% RPM change (TO versus max rpm) should
> have such a significant impact on the time limitations? IT IS MUCH THE
> SAME WAY AS THE RED LINE ON YOUR AUTOMOBILE TACHOMETER. THE VALVE TRAIN
> MECHANISM IS MOST LIKELY THE KEY ISSUE. HIGHER RPM REQUIRES
> DIFFERENT/STRONGER VALVE SPRINGS AND PROBABLY A DIFFERENT LIFTER DESIGN.
> WE ALREADY HAVE ROLLER ROCKER ARMS, WHICH ARE ALWAYS USED IN HIGH
> PERFORMANCE ENGINES. ADDITIONALLY, THE ABILITY TO INTAKE THE FUEL/AIR
> MIXTURE AS WELL AS EXHAUST THE COMBUSTED GASES REQUIRES BETTER "FLOWING"
> OR PORTING OF THE INTAKE AND EXHAUST AREAS TO REDUCE THE INHERANT FRICTION
> OF THE PROCESSES. THE 2% LIMITATION IS MOST LIKELY THERE TO PREVENT VALVE
> MECHANISM (PRIMARILY THE VALVE SPRINGS) FAILURE BY OVER REVING THE ENGINE.
> HAVE YOU EVER SEEN AN INTERNAL COMBUSTION ENGINE BREAK A VALVE SPRING AT
> HIGH RPM AND WHAT THE RESULTS ARE WHEN THIS HAPPENS? IT REALLY MAKES A
> MESS.
>
> Is this a prop governor, rather than an engine, limitation perhaps? NO.
REMEMBER, ALL INTERNAL COMBUSTION ENGINES ARE NOTHING MORE THAN BIG AIR
PUMPS. IF YOU CAN MAKE THE ENGINE COMBUST MORE EFFICIENTLY, YOU CAN
INCREASE THE HORSEPOWER. ONE OF THE EASIEST AND SIMPLIST WAYS TO INCREASE
HORSEPOWER IS: ADVANCE THE ENGINE TIMING FROM THE STANDARD 14-15 DEGREES
BTDC TO 17 DEGREES BTDC.
>
> All insight gratefully received ... I've some new guys in our Yak
> syndicate
> who have spotted these apparent anomalies, so I'm trying to get some
> definitive answers and a supporting explanation ... hence the detail!
>
> Cheers, Rob
>
>
>
Message 3
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--> Yak-List message posted by: "Duncan aka Russ" <Duncan1574@ExecPc.com>
As one of the many at MTW/OSH I will pas on to you all that Roger's passing
stuck us all very hard. He was a great pilot, friend, and man.
A short story about heaven................
The aviator stood at the Pearly Gates and awaited his turn in line.
Around him the sky was the brightest blue and the clouds high-white and
edged in a golden line.
The sun shown high and bright and the breeze was cool and fair.
"Great flying weather" he thought "I guess I'll like it here".
As he approached St. Peter who with pen on the scroll of life did mark.
"Ah! An aviator I see. Are you ready to embark?"
"Yes sir" replied the aviator, " I hope I'm still allowed to fly"
"Oh yes!" replied St. Peter "and you'll find the flying great.
"The lighting will always be way below you,
The stars will be close at hand,
Why you can reach out and touch them,
There in their sparkling band.
The radio beacons will be steady.
No crackle, buzz, or wrong.
Their signals sweet and steady
Not unlike an angel's song.
The aircraft are strong and worthy
With controls smooth and sound.
Their engines never cough or sputter
Like the Maker they'll never let you down.
Yes the flying Here is all you've ever desired"
However my son," St. Peter smiled
"landings Here, are not required."
Message 4
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--> Yak-List message posted by: "Richard Goode" <richard.goode@russianaeros.com>
In reply to Rob Rowes questions:
a.. The official power is 360hp minus two percent - i.e. 353 minimum.=20
b.. The most that I have seen is 373, although I have heard higher figures quoted
for standard engines, but never seen what I would consider to be proper
Vedeneyev / VMP log-books to confirm.
c.. There are of course different methods of measuring horse power - the Russians
do it while powering all the ancillaries: whereas typically American manufacturers
do not.=20
d.. It is 360hp at 125mm over ambient - and on a cold high-pressure day you can
do a bit better than this.
e.. The one minute at 101% is quite conservative - many serious Sukhoi pilots
fly in competitions at 103%, although, wear etc goes up dramatically with the
extra revs.=20
f.. So 101/103 % is either obtained by deliberately setting the governor high
or through an overspeed.
g.. We know of an engine that went to 131% ( it had a recording tachometer) and
seemed fine.
h.. Only reason for the impact of 2% change is that the wear and stress are very
exponential - i.e. 2% extra is possibly 10 times extra stress (a total guess).
i.. absolutely no limitation on prop governor.
Hope this helps.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Mob: +44 (0) 7768 610389
Fax: +44 (0) 1544 340129
www.russianaeros.com
dangerous content by the http://www.invictawiz.com
MailScanner, and is believed to be clean.
Message 5
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--> Yak-List message posted by:
Subject: RE: Yak-List: Max G Light
Concur with Mark Williamson.
To get rid of the light and tone, simply unplug the G meter. It happens all
the time. I have taken several of these things apart and have repaired them
myself, they are not TOO hard to figure out. Inside you will see the set
arms that Mark Williamson is talking about that allow you to set the G
limits of the warning light. If the G Meter is still working A-OK, then it
really does make sense just to switch it with the one in the rear cockpit!
Mark Bitterlich
-----Original Message-----
From: Mark Williamson [mailto:yakk52@verizon.net]
Subject: Re: Yak-List: Max G Light
--> Yak-List message posted by: "Mark Williamson" <yakk52@verizon.net>
the meter has several contact switches in it - one for neg and one for pos
max g. sounds like it's broken and jammed up against one or the other. you
can replace the front meter with the rear. the light and buzzer are
controlled via the connector in the back of the meter. also, check the "set
screw" in the rear of the g-meter and make sure it hasn't vibrated into a
"set" position.
btw: i'm looking for parts to repair a g-meter. so if you decide to throw
away the broken meter then i wouldn't mind having it. i need a gear-like
thingy that has stripped in one of mine.
mark
> --> Yak-List message posted by: Edwin Curry <EACurry@ev1.net>
>
> Let me pose a question to the brains on this list. I have original
> Russian G Meters in my Yak 52. The meter in the front cockpit is no
> longer working correctly. Could this cause the "Max G" light to
> illuminate? I can reset the meter on the ground and the light will stay
> on along with the tone in the headset. When I fly, the meter gives very
> erroneous readings. What do you think? What should I do next?
> Edwin
> N108GC
> Yak 52
>
>
>
Message 6
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| Subject: | Re: M14P limitations |
--> Yak-List message posted by: "Rob Rowe" <yak-list@robrowe.plus.com>
Richard, Dennis & the off-listers ... thanks for your feedback.
Cheers, Rob
Message 7
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| Subject: | Rodger's Tribute |
--> Yak-List message posted by: "Terry Calloway" <tcalloway@datatechnique.com>
Dear Friends,
Today, in Tulsa, Oklahoma we celebrated the life of Rodger Modglin. My
friend.
If you have not already, please take a moment to visit our website and
view the tribute to Rodger at www.teamredwarbirds.com . You can view the
video tribute by clicking on the cover photo.
Also, please take a moment to sign the guestbook, the family is reading
the comments from visitors and it is really helping them get through
these tough times. Thank you so much if you have already done so.
We will celebrate a final time in Ava, IL on Saturday July 30 at 3:00
PM. A number of our fellow friends and aviators have expressed an
interest in attending. RPA friends will fly the missing man formation.
The details are that all will be flying into Carbondale/Murphysboro,
KMDH. We are making arrangements for rooms and transportation for many,
so if you need assistance, feel free to call Zoe at 620-235-1000.
Pilots will celebrate Rodger's life at the services wearing their
flight suits, as is Rodger.
Saturday evening plans are still being firmed, but please plan to
attend if you can.
Godspeed,
Terry "Pumper" Calloway
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