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Over- priming

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richard.goode(at)russiana
Guest

Posted: Tue Sep 29, 2009 1:24 am Post subject: Over- priming

In my view ten blades are not enough - I  would suggest at least fifteen.  

  

 The point of my method is that it prevents  the need of getting in and out of the aircraft, which one really does not want  to do at the best of times particularly if it is cold/raining.   

  

 So if the engine is in reasonable condition;  the carburettor primed; 3/5 pumps to the cylinder, the engine should start  within a revolution of the prop on every occasion.   

  

 The big mistake is to treat the air start as  a form of starter-motor.   

  

 The engine will either start, which is fine;  kick-back, which means it is over-primed; or not fire which means that it is  under primed.  

  

 IF it does kick-back then switch everything  off; and now you do need to get out, and wind the prop through (say) six  revolutions, and then start again. 

  

 If it is under primed, then give it some  more prime. 

  

 The essence of it is that everything can be  done from inside the cockpit.  

  

  

 Richard Goode Aerobatics 

Rhodds Farm  

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

  

 Tel: +44 (0) 1544 340 120

Fax: +44 (0)  1544 340 129 

www.russianaeros.com



   [quote][b]

dougsappllc(at)gmail.com
Guest

Posted: Tue Sep 29, 2009 9:14 am Post subject: Over- priming

All,During a conversation with the folks in China who are in the know with respect to what is done to their engines at overhaul stated that it is the top clys which are always in the poorest condition when they receive the engines for overhaul.  They confirmed that this was due to overpriming.  All food for thought.

 



Doug



On Tue, Sep 29, 2009 at 2:17 AM, Richard Goode <richard.goode(at)russianaeros.com (richard.goode(at)russianaeros.com)> wrote:

  	  Quote: 	
		          

 In my view ten blades are not enough - I  would suggest at least fifteen.  

  

 The point of my method is that it prevents  the need of getting in and out of the aircraft, which one really does not want  to do at the best of times particularly if it is cold/raining.   

  

 So if the engine is in reasonable condition;  the carburettor primed; 3/5 pumps to the cylinder, the engine should start  within a revolution of the prop on every occasion.   

  

 The big mistake is to treat the air start as  a form of starter-motor.   

  

 The engine will either start, which is fine;  kick-back, which means it is over-primed; or not fire which means that it is  under primed.  

  

 IF it does kick-back then switch everything  off; and now you do need to get out, and wind the prop through (say) six  revolutions, and then start again. 

  

 If it is under primed, then give it some  more prime. 

  

 The essence of it is that everything can be  done from inside the cockpit.  

  

  

 Richard Goode Aerobatics 

Rhodds Farm  

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

  

 Tel: +44 (0) 1544 340 120

Fax: +44 (0)  1544 340 129 

www.russianaeros.com



    	  Quote: 	
		  



et="_blank">http://www.matronics.com/Navigator?Yak-List

tp://forums.matronics.com

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-- 

 Douglas Sapp

Doug Sapp LLC

18B Riverview Road

Omak WA 98841

PH 509-826-4610

Fax 509-826-3644

 

  [quote][b]

mark.bitterlich(at)navy.m
Guest

Posted: Tue Sep 29, 2009 2:19 pm Post subject: Over- priming

This may be a ridiculous statement, but it dawns on me that not all of

these engines sit at the same angle when mounted in the aircraft.  For

example, the YAK-50 obviously sits canted back, while on the 52 it is

fairly level.  Would this result in less fuel going down into the top

cylinder or not?  Just wondering. 



Mark Bitterlich

 



--

richard.goode(at)russiana
Guest

Posted: Tue Sep 29, 2009 11:38 pm Post subject: Over- priming

I don't think that it would affect priming  but it does increase the susceptiblity of the tail-wheel planes to  hydraulic-lock,since the oil can pool more easily in the intake  tubes.

 Richard

  

 Richard Goode Aerobatics

Rhodds Farm

Lyonshall

Hereford

HR5  3LW

United Kingdom

  

 Tel:   +44 (0) 1544 340120

Fax:  +44 (0) 1544  340129

www.russianaeros.com



 [quote]   ---

viperdoc(at)mindspring.co
Guest

Posted: Wed Sep 30, 2009 5:11 am Post subject: Over- priming

For the 50’s, I jack my tail up about 2 feet with a standard hydraulic floor jack if she is going to sit for a few days. Doing that does increase the oil drainage out of the intake drains . I have found I have less oil draining out of the intakes during pull through doing this.  

The next item on the agenda is to install a sump drain line to plug into a “clean container” for drainage when she is going to sit for  period of time.   

Viperdoc  

YAK 50 N78YK  

       

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Richard Goode

 Sent: Wednesday, September 30, 2009 2:29 AM

 To: yak-list(at)matronics.com

 Subject: Re: Over- priming  

  

  

     

I don't think that it would affect priming but it does increase the susceptiblity of the tail-wheel planes to hydraulic-lock,since the oil can pool more easily in the intake tubes.  

    

Richard  

    

   

    

Richard Goode Aerobatics

 Rhodds Farm

 Lyonshall

 Hereford

 HR5 3LW

 United Kingdom  

    

   

    

Tel:   +44 (0) 1544 340120

 Fax:  +44 (0) 1544 340129

 www.russianaeros.com  

  [quote]    

----- Original Message -----   

    

From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E (mark.bitterlich(at)navy.mil)   

    

To: yak-list(at)matronics.com (yak-list(at)matronics.com)   

    

Sent: Tuesday, September 29, 2009 11:17 PM  

    

Subject: RE: Over- priming  

    

   

  

--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>

 

 This may be a ridiculous statement, but it dawns on me that not all of

 these engines sit at the same angle when mounted in the aircraft.  For

 example, the YAK-50 obviously sits canted back, while on the 52 it is

 fairly level.  Would this result in less fuel going down into the top

 cylinder or not?  Just wondering. 

 

 Mark Bitterlich

  

 

 --

jan.mevis(at)informavia.b
Guest

Posted: Wed Sep 30, 2009 6:26 am Post subject: Over- priming

Very good idea, I’ll try that too.  

   

Jan  

   

YK50 RA2005K  

       

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Roger Kemp M.D.

 Sent: woensdag 30 september 2009 15:09

 To: yak-list(at)matronics.com

 Subject: RE: Over- priming  

  

  

   

For the 50’s, I jack my tail up about 2 feet with a standard hydraulic floor jack if she is going to sit for a few days. Doing that does increase the oil drainage out of the intake drains . I have found I have less oil draining out of the intakes during pull through doing this.  

The next item on the agenda is to install a sump drain line to plug into a “clean container” for drainage when she is going to sit for  period of time.   

Viperdoc  

YAK 50 N78YK  

       

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Richard Goode

 Sent: Wednesday, September 30, 2009 2:29 AM

 To: yak-list(at)matronics.com

 Subject: Re: Over- priming  

  

  

     

I don't think that it would affect priming but it does increase the susceptiblity of the tail-wheel planes to hydraulic-lock,since the oil can pool more easily in the intake tubes.  

    

Richard  

    

   

    

Richard Goode Aerobatics

 Rhodds Farm

 Lyonshall

 Hereford

 HR5 3LW

 United Kingdom  

    

   

    

Tel:   +44 (0) 1544 340120

 Fax:  +44 (0) 1544 340129

 www.russianaeros.com  

  [quote]    

----- Original Message -----   

    

From: Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E (mark.bitterlich(at)navy.mil)   

    

To: yak-list(at)matronics.com (yak-list(at)matronics.com)   

    

Sent: Tuesday, September 29, 2009 11:17 PM  

    

Subject: RE: Over- priming  

    

   

  

--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>

 

 This may be a ridiculous statement, but it dawns on me that not all of

 these engines sit at the same angle when mounted in the aircraft.  For

 example, the YAK-50 obviously sits canted back, while on the 52 it is

 fairly level.  Would this result in less fuel going down into the top

 cylinder or not?  Just wondering. 

 

 Mark Bitterlich

  

 

 --

mark.bitterlich(at)navy.m
Guest

Posted: Wed Sep 30, 2009 11:41 am Post subject: Over- priming

Some folks run a line from the sump drain to an electric pump and then

pump the oil directly back to the main tank.  Works pretty good.  But,

the way they attach this to the sump point scares me a little.  It's

FRAGILE.  If that were to break, all your engine oil would run right out

of it, and you would never know it was happening in flight.  



Mark

--

mark.bitterlich(at)navy.m
Guest

Posted: Wed Sep 30, 2009 11:53 am Post subject: Over- priming

If you have intake drains, is it not better to let the oil flow out of

the cylinders, into the intakes and then out the drain?  Is it better to

try and contain the oil in the cylinder....??  I don't quite get why

keeping the engine level would INCREASE the oil out of the intake

drains.  What is the logic behind that?  No M-14 equipped tail wheel

airplane that I know of EVER jacks their plane up to keep it level that

I know of Doc.  Where did you come up with that?  



On the other hand, if you keep the engine level, more of the oil will

stay in the cylinder, decreasing the oil coming out of the intake drain

(as you said) when you pull it through, but INCREASING the amount of oil

coming out the exhaust, and increasing the chance of hydraulic lock.  



I must be missing something here.  Not disagreeing, I just don't get it.

Mark

--

viperdoc(at)mindspring.co
Guest

Posted: Wed Sep 30, 2009 7:22 pm Post subject: Over- priming

Mark,

Instead of the nose sitting at 13.4 deg, the angle is decreased to

approximately 8-9 degrees with the jack under the tail. The plane is not

level with this system. I came up with the idea when I pulled blades on

morning after the palne had been sitting for a couple of weeks. When I

pulled 14 blades, I got a fair amount oil out then just as I ready to close

the drain, another few globules of oil began to floe. 

Since I have been doing this, I seldom have a problem with the continued

drainage of oil since that time.



--

viperdoc(at)mindspring.co
Guest

Posted: Wed Sep 30, 2009 7:23 pm Post subject: Over- priming

This system would require the closure of the sump drain prior to T.O.

Doc



--

mark.bitterlich(at)navy.m
Guest

Posted: Thu Oct 01, 2009 8:38 am Post subject: Over- priming

The question is why that is happening.  Oil is oil.  It is going to do

what it does, no matter how the aircraft is jacked, leveled, or

whatever.  Changing the angle is only going to impact where that oil

ends up.  At the extreme side, if we had the tail of the aircraft

pointing straight up, ... As in fully nose down, it would take a lot in

order to get any oil into the intake tubes.  Thus all the oil stays in

the cylinders where it originally came from, or flows out the exhaust.

Sorta.   



At the other extreme, with the nose straight up, any oil from the

cylinders is going to try to go out an open valve if it can.  If the

intake is open, it will flow back into the intake tubes.  



At angles in-between those two extremes, you will get various amounts of

oil into the intake tubes.  



If there is too much oil in the cylinders, you are going to have to end

up pulling spark plugs, or you bend a rod.  



If there is too much oil LEFT in the intake tubes when you go to start

it, you take a chance of gulping in a big slug of oil and then bending a

rod again.  



Seems to me that either thing is a bad thing.  



The real fix is to totally prevent oil from getting into the damn engine

in the first place.   The factory method to prevent that is a ball check

valve in the accessory drive oil pump area.  Having this check valve

working properly prevents oil from flowing through the oil pump gear and

then into the engine itself.  Making that valve work perfectly is hard

to do.  You can make it work BETTER, but it's hard to make it work

PERFECTLY.   



In the end, the very best method to prevent this is to just TURN OFF THE

OIL SUPPLY!  Kevin Kimball sells a valve that you can put in the supply

oil line that does just that.  It also includes an electric position

switch that you can tie into your start circuit to help prevent starting

the airplane with the oil system shut off, which is obviously a bad

thing.  Clearly, the valve is the best method to stop all this nonsense,

to where you can pull through NO blades if you want to, and be able and

jump in and start the aircraft just like a Cessna.  (Heaven forbid!)  Of

course the danger is that if you screw up, you just ruined the engine.

Of course if you start up with a hydraulic lock, you ALSO will destroy

at least one cylinder, and possibly the whole engine as well.  In the

meantime we yank the prop through, carefully checking for "how it feels"

for the fist 8 blades or so.  You can bend a rod simply by pulling it

through too hard with oil in those cylinders!  



I think a manual shut off valve is the right choice for me.  It also

means you won't need a sump drain pump, or bleed system, no jacks under

the tail, nothing.  Just land, shut off the engine, turn off the valve.

YOU'RE DONE.  Comes time to fly again, turn on the valve, start the

engine.  Personally, I would tie the electrical switch not only into the

starter circuit, but also to be a big red "DON'T BE AN IDIOT" light in

the cockpit.  Big flashing red one.  



Mark Bitterlich



--

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