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Engine Failure in a Yak-50
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elmar.h(at)shaw.ca
Guest

Posted: Sat Oct 16, 2010 10:39 pm Post subject: Engine failure in a Yak-50

Why does the propeller windmill on 

a ceased engine, sheared gearbox?



Elmar

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Sun Oct 17, 2010 6:27 am Post subject: Engine failure in a Yak-50

Any time a propeller can turn, it can potentially windmill, especially  

if the resistance is low.



As the airplane moves, the air flow creates pressure differentials in  

the propeller blades, which are airfoils. This forces the blades to  

move in the direction of the leading edge, thereby converting this  

kinetic energy to torque acting on the propeller shaft.



On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:



 	  Quote: 	
		   



 Why does the propeller windmill on

 a ceased engine, sheared gearbox?



 Elmar

mark.bitterlich(at)navy.m
Guest

Posted: Sun Oct 17, 2010 10:40 am Post subject: Engine failure in a Yak-50

I think the question was addressed more to WHY it was wind-milling Eric.  I think he meant "seized" instead of "ceased".  

 

In any event, I believe the pilot said something like "the engine just seized", etc.  And honestly I am not sure if I heard that right either and am too lazy to go back and listen to it again.    But, I think the issue was since the engine ran out of oil, and seized, why was the prop still wind milling?

 

It's a good question really and one I hope I never find out the answer to it PERSONALLY.  Maybe someone else can explain how the engine: 

 

1.  Ran out of oil. 

2.  Stopped producing power.  

3.  Still managed to keep spinning from the wind load induced to the prop?  

 

If the reduction gearbox came apart, one would think the prop would have spun a LOT faster.  Which lends one to believe that the engine stopped producing power from a lack of oil, which usually results in bearings just coming apart and the engine seizing.  Yet the prop doesn't seem to show any signs of it suddenly stopping and then start spinning again etc.  

 

Maybe something like the cam drive broke?  

 

Anyway, interesting question.    I have no idea.  Maybe someone else can answer it. 

 

Mark Bitterlich

 



________________________________



From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall

Sent: Sun 10/17/2010 10:18 AM

To: yak-list(at)matronics.com

Subject: Re: Re: Engine failure in a Yak-50






Any time a propeller can turn, it can potentially windmill, especially 

if the resistance is low.



As the airplane moves, the air flow creates pressure differentials in 

the propeller blades, which are airfoils. This forces the blades to 

move in the direction of the leading edge, thereby converting this 

kinetic energy to torque acting on the propeller shaft.



On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:



 	  Quote: 	
		   



 Why does the propeller windmill on

 a ceased engine, sheared gearbox?



 Elmar

viperdoc(at)mindspring.co
Guest

Posted: Sun Oct 17, 2010 1:02 pm Post subject: Engine failure in a Yak-50

I can answer on question. It ran out of oil because the oil pressure

adjustment plug was not safety wired and vibrated our. My question is if you

are losing oil pressure as this bolt started to work its' way back out would

there not have been an initial lower than normal pressure seen as this thing

begins to work out?

Doc



--

bwade154(at)yahoo.com
Guest

Posted: Sun Oct 17, 2010 1:13 pm Post subject: Engine failure in a Yak-50

What Elmar and I think it was Barry is implying is that when most engines cease things inside become molten metal and lockup I've done this numerous times racing motorcycle's. And both these guys as well as myself are wondering if the engine did cease - lockup due to lack of oil why did the prop continue to windmill the cyl temp remain normal and the oil temp remain normal? There was an oil additive that would allow an engine to run for a very long time without oil I think the FAA almost certified it I guess what I'm saying is the engine should have run much longer with 0 oil psi and then make bad banging noises as it shed parts. I suppose sense Richard has the airplane he could elaborate on the engine damage. What could have happened is the pilot pulled the fuel leaver starving  the engine of fuel after seeing no oil pressure, after all the oil was lost there would be no more oil going over the sensor hence lowering oil temp, and no fuel no heat at the cyl head? just my thought Richard would know. 

  

 Bill Wade



 

   From: Eric Wobschall <eric(at)buffaloskyline.com>

To: yak-list(at)matronics.com

Sent: Sun, October 17, 2010 10:18:12 AM

Subject: Re: Yak-List: Re: Engine failure in a Yak-50



--> Yak-List message posted by: Eric Wobschall <eric(at)buffaloskyline.com (eric(at)buffaloskyline.com)>



Any time a propeller can turn, it can potentially windmill, especially  

if the resistance is low.



As the airplane moves, the air flow creates pressure differentials in  

the propeller blades, which are airfoils. This forces the blades to  

move in the direction of the leading edge, thereby converting this  

kinetic energy to torque acting on the propeller  shaft.



On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:



 	  Quote: 	
		   --> Yak-List message posted by: Elmar Hegenauer <elmar.h(at)shaw.ca (elmar.h(at)shaw.ca)>



 Why does the propeller windmill on

 a ceased engine, sheared gearbox?



 Elmar

sp;       -                    -Matt Drall============


	


         [quote][b]

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Sun Oct 17, 2010 2:09 pm Post subject: Engine failure in a Yak-50

If the gearbox is "sheared", what does it matter how seized things are aft of it?



My understanding is that the real hazard is when the planetary gears lock up. That's when the engine twists itelf off of the airplane.



On Oct 17, 2010, at 5:09 PM, bill wade wrote:

 	  Quote: 	
		  What Elmar and I think it was Barry is implying is that when most engines cease things inside become molten metal and lockup I've done this numerous times racing motorcycle's. And both these guys as well as myself are wondering if the engine did cease - lockup due to lack of oil why did the prop continue to windmill the cyl temp remain normal and the oil temp remain normal? There was an oil additive that would allow an engine to run for a very long time without oil I think the FAA almost certified it I guess what I'm saying is the engine should have run much longer with 0 oil psi and then make bad banging noises as it shed parts. I suppose sense Richard has the airplane he could elaborate on the engine damage. What could have happened is the pilot pulled the fuel leaver starving the engine of fuel after seeing no oil pressure, after all the oil was lost there would be no more oil going over the sensor hence lowering oil temp, and no fuel no heat at the cyl head? just my thought Richard would know. 

 

Bill Wade

From: Eric Wobschall <eric(at)buffaloskyline.com (eric(at)buffaloskyline.com)>

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

Sent: Sun, October 17, 2010 10:18:12 AM

Subject: Re: Re: Engine failure in a Yak-50



--> Yak-List message posted by: Eric Wobschall <eric(at)buffaloskyline.com (eric(at)buffaloskyline.com)>



Any time a propeller can turn, it can potentially windmill, especially  

if the resistance is low.



As the airplane moves, the air flow creates pressure differentials in  

the propeller blades, which are airfoils. This forces the blades to  

move in the direction of the leading edge, thereby converting this  

kinetic energy to torque acting on the propeller shaft.



On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:



 	  Quote: 	
		   --> Yak-List message posted by: Elmar Hegenauer <elmar.h(at)shaw.ca (elmar.h(at)shaw.ca)>



 Why does the propeller windmill on

 a ceased engine, sheared gearbox?



 Elmar

sp;       -                   -Matt Drall============


	


 	  Quote: 	
		  



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

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/contribution



	


	


 [quote][b]

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Sun Oct 17, 2010 2:14 pm Post subject: Engine failure in a Yak-50

Actually, I sort of doubt the engine was seized. However, when the oil  

runs out and CHT skyrockets, combustion is screwed up and numerous  

things are likely to happen to make the engine lose power.

On Oct 17, 2010, at 2:35 PM, Bitterlich, Mark G CIV Det Cherry Point,  

MALS-14 64E wrote:

 	  Quote: 	

 Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>

 I think the question was addressed more to WHY it was wind-milling  

 Eric.  I think he meant "seized" instead of "ceased".

 In any event, I believe the pilot said something like "the engine  

 just seized", etc.  And honestly I am not sure if I heard that right  

 either and am too lazy to go back and listen to it again.    But,  

 I think the issue was since the engine ran out of oil, and seized,  

 why was the prop still wind milling?

 It's a good question really and one I hope I never find out the  

 answer to it PERSONALLY.  Maybe someone else can explain how the  

 engine:

 1.  Ran out of oil.

 2.  Stopped producing power.

 3.  Still managed to keep spinning from the wind load induced to the  

 prop?

 If the reduction gearbox came apart, one would think the prop would  

 have spun a LOT faster.  Which lends one to believe that the engine  

 stopped producing power from a lack of oil, which usually results in  

 bearings just coming apart and the engine seizing.  Yet the prop  

 doesn't seem to show any signs of it suddenly stopping and then  

 start spinning again etc.

 Maybe something like the cam drive broke?

 Anyway, interesting question.    I have no idea.  Maybe someone else  

 can answer it.

 Mark Bitterlich

 ________________________________

 From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall

 Sent: Sun 10/17/2010 10:18 AM

 To: yak-list(at)matronics.com

 Subject: Re: Re: Engine failure in a Yak-50

 >

 Any time a propeller can turn, it can potentially windmill, especially

 if the resistance is low.

 As the airplane moves, the air flow creates pressure differentials in

 the propeller blades, which are airfoils. This forces the blades to

 move in the direction of the leading edge, thereby converting this

 kinetic energy to torque acting on the propeller shaft.

 On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:

> 

>

> Why does the propeller windmill on

> a ceased engine, sheared gearbox?

>

> Elmar

dsavarese0812(at)bellsout
Guest

Posted: Mon Oct 18, 2010 2:50 am Post subject: Engine failure in a Yak-50

Sounds right to me.

 Dennis

 [quote]   ---

george.coy(at)gmail.com
Guest

Posted: Mon Oct 18, 2010 6:03 am Post subject: Engine failure in a Yak-50

I have flown a radial engine with no oil pressure for 40 minutes (over the North Atlantic). It was in a Russian AN-2. The engine was an ASH 62 engine (Russian Wright R-1820).  We did not change the power setting and the engine continued to run and make power. As soon as the power setting was reduced, the engine wind milled for a bit then stopped. We made a successful landing at an airport in Iceland.  

Examination of the engine found the oil cooler packed with fine metal chips. The front oil screen required a pry bar to be removed. It was packed with metal fines and included many chunks the size of a thumbnail. The cause of the oil loss was a faulty oil line. It was installed with a significant twist that slowly unscrewed the rubber to metal joint until it developed a leak.  We noticed a loss of oil pressure about an hour before the oil pressure finally went to zero. During that time, the oil temp never changed until the we lost it all together. The cylinder head temp remained normal until the descent.  

One significant difference was the fact that the AN2 had a “normal” propeller not an aerobatic prop. When the oil pressure was lost, it went to fine (cruise pitch). Thus we were able to keep going. The Yaks and other aerobatic aircraft propellers will go to coarse pitch upon loss of oil pressure. This significantly affects the ability to keep going.   

          Another time, I lost an oil plug in a Zlin 50 during local aerobatic practice. The oil pressure dropped and the prop went to full coarse pitch. It became necessary to dive to keep the airspeed in an acceptable range for a landing.  Landed successfully with no further damage at the airport.    

          I have seen a seized M14P where the engine seized and the propeller shaft broke just inside the front bearing. The prop wind milled at a very high speed according to the pilot. He made a successful landing as well. The cause of the seizure was a connecting rod that was partially damaged by a hydraulic lock. It failed and caused others to jam and fail. It was a sudden seizure.   

          I was doing my final prep in a DC3 for my type rating and during an instrument approach (under the hood), the left engine did not “feel right”. There were no indications of any problems on the instruments, no abnormal vibrations, it just did not sound right. I broke off approach and landed. Turned out that one connecting rod had broken and the piston went to the top of the cylinder and stayed there. The remaining piece of connecting rod was short enough that it did not flail around and cause much other damage.   

          You can take what you want from my experiences, but I have learned to TRUST radial engines.  

   

   

   

George Coy  

CAS Ltd.  

714 Airport Rd.  

Swanton VT 05488  

802-868-5633 off  

802-363-5782 cell  

george.coy(at)gmail.com (george.coy(at)gmail.com)  

http://coyafct.com/  

SKYPE george.coy  

   [quote] [b]

mark.bitterlich(at)navy.m
Guest

Posted: Mon Oct 18, 2010 10:05 am Post subject: Engine failure in a Yak-50

When an engine runs out of oil, it will always seize.  The only real issue is how long it will take. 

Mark Bitterlich

________________________________

From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall

Sent: Sun 10/17/2010 6:11 PM

To: yak-list(at)matronics.com

Subject: Re: Re: Engine failure in a Yak-50

Actually, I sort of doubt the engine was seized. However, when the oil 

runs out and CHT skyrockets, combustion is screwed up and numerous 

things are likely to happen to make the engine lose power.

On Oct 17, 2010, at 2:35 PM, Bitterlich, Mark G CIV Det Cherry Point, 

MALS-14 64E wrote:

 	  Quote: 	

 Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>

 I think the question was addressed more to WHY it was wind-milling 

 Eric.  I think he meant "seized" instead of "ceased".

 In any event, I believe the pilot said something like "the engine 

 just seized", etc.  And honestly I am not sure if I heard that right 

 either and am too lazy to go back and listen to it again.    But, 

 I think the issue was since the engine ran out of oil, and seized, 

 why was the prop still wind milling?

 It's a good question really and one I hope I never find out the 

 answer to it PERSONALLY.  Maybe someone else can explain how the 

 engine:

 1.  Ran out of oil.

 2.  Stopped producing power.

 3.  Still managed to keep spinning from the wind load induced to the 

 prop?

 If the reduction gearbox came apart, one would think the prop would 

 have spun a LOT faster.  Which lends one to believe that the engine 

 stopped producing power from a lack of oil, which usually results in 

 bearings just coming apart and the engine seizing.  Yet the prop 

 doesn't seem to show any signs of it suddenly stopping and then 

 start spinning again etc.

 Maybe something like the cam drive broke?

 Anyway, interesting question.    I have no idea.  Maybe someone else 

 can answer it.

 Mark Bitterlich

 ________________________________

 From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall

 Sent: Sun 10/17/2010 10:18 AM

 To: yak-list(at)matronics.com

 Subject: Re: Re: Engine failure in a Yak-50

 >

 Any time a propeller can turn, it can potentially windmill, especially

 if the resistance is low.

 As the airplane moves, the air flow creates pressure differentials in

 the propeller blades, which are airfoils. This forces the blades to

 move in the direction of the leading edge, thereby converting this

 kinetic energy to torque acting on the propeller shaft.

 On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:

> 

>

> Why does the propeller windmill on

> a ceased engine, sheared gearbox?

>

> Elmar

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Mon Oct 18, 2010 10:47 am Post subject: Engine failure in a Yak-50

I'm saying that if it was turning, it didn't seize. Or rather, it  

seems unlikely that something sheared in the gearbox allowing the prop  

to turn after seizure.

On Oct 18, 2010, at 2:00 PM, Bitterlich, Mark G CIV Det Cherry Point,  

MALS-14 64E wrote:



 	  Quote: 	
		   

 Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>



 When an engine runs out of oil, it will always seize.  The only real  

 issue is how long it will take.



 Mark Bitterlich

 ________________________________



 From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall

 Sent: Sun 10/17/2010 6:11 PM

 To: yak-list(at)matronics.com

 Subject: Re: Re: Engine failure in a Yak-50



 

 >



 Actually, I sort of doubt the engine was seized. However, when the oil

 runs out and CHT skyrockets, combustion is screwed up and numerous

 things are likely to happen to make the engine lose power.

 On Oct 17, 2010, at 2:35 PM, Bitterlich, Mark G CIV Det Cherry Point,

 MALS-14 64E wrote:



> 

> Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>

>

> I think the question was addressed more to WHY it was wind-milling

> Eric.  I think he meant "seized" instead of "ceased".

>

> In any event, I believe the pilot said something like "the engine

> just seized", etc.  And honestly I am not sure if I heard that right

> either and am too lazy to go back and listen to it again.    But,

> I think the issue was since the engine ran out of oil, and seized,

> why was the prop still wind milling?

>

> It's a good question really and one I hope I never find out the

> answer to it PERSONALLY.  Maybe someone else can explain how the

> engine:

>

> 1.  Ran out of oil.

> 2.  Stopped producing power.

> 3.  Still managed to keep spinning from the wind load induced to the

> prop?

>

> If the reduction gearbox came apart, one would think the prop would

> have spun a LOT faster.  Which lends one to believe that the engine

> stopped producing power from a lack of oil, which usually results in

> bearings just coming apart and the engine seizing.  Yet the prop

> doesn't seem to show any signs of it suddenly stopping and then

> start spinning again etc.

>

> Maybe something like the cam drive broke?

>

> Anyway, interesting question.    I have no idea.  Maybe someone else

> can answer it.

>

> Mark Bitterlich

> ________________________________

>

> From: owner-yak-list-server(at)matronics.com on behalf of Eric Wobschall

> Sent: Sun 10/17/2010 10:18 AM

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

> Subject: Re: Re: Engine failure in a Yak-50

>

> 

>>

>

> Any time a propeller can turn, it can potentially windmill,  

> especially

> if the resistance is low.

>

> As the airplane moves, the air flow creates pressure differentials in

> the propeller blades, which are airfoils. This forces the blades to

> move in the direction of the leading edge, thereby converting this

> kinetic energy to torque acting on the propeller shaft.

>

> On Oct 17, 2010, at 12:19 AM, Elmar Hegenauer wrote:

>

>> 

>>

>> Why does the propeller windmill on

>> a ceased engine, sheared gearbox?

>>

>> Elmar

>>

>>

>>

>>

>>

>>

>

>

talew(at)bellsouth.net
Guest

Posted: Mon Oct 18, 2010 11:25 am Post subject: Engine failure in a Yak-50

I believe there is a stress relief point in the engine to allow the prop

to break free of a seized engine . If not ,  the prop sudden stop could easily 

cause the

engine to depart the aircraft .

I could be wrong !

Terry Lewis

---

viperdoc(at)mindspring.co
Guest

Posted: Mon Oct 18, 2010 12:15 pm Post subject: Engine failure in a Yak-50

Did you read Rob Rowe's post. He has that engine. The Prop shaft sheared at

the gear box when the pistons froze in the sleeves. Air flow over the

airfoils (the prop blades) provided the torque for the blades to continue to

turn when the engine seized. Therefore, you get a wind milling prop.

Doc



--

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Mon Oct 18, 2010 2:35 pm Post subject: Engine failure in a Yak-50

I've got to shop reading these emails in reverse order. Would prevent  

a lot of stupid (er, I mean already answered) questions.

On Oct 18, 2010, at 3:23 PM, T A LEWIS wrote:



[quote] 



 I believe there is a stress relief point in the engine to allow the  

 prop

 to break free of a seized engine . If not ,  the prop sudden stop  

 could easily

 cause the

 engine to depart the aircraft .

 I could be wrong !

 Terry Lewis

 ---

george(at)gesoco.com
Guest

Posted: Wed Oct 20, 2010 6:23 am Post subject: Engine Failure in a Yak-50

I would mention that when we did the Yak-52TW we had the factory reinforce

the front canopy bow. The plan being that if someone did an off field

landing and flipped the airplane that there would be some protection from

being crushed. It would bridge from the vertical stab to the canopy bow to

the nose cowl. 



George Coy

CAS Ltd.

714 Airport Rd.

Swanton VT 05488

802-868-5633 off

802-363-5782 cell

george.coy(at)gmail.com

http://coyafct.com/

SKYPE george.coy

mark.bitterlich(at)navy.m
Guest

Posted: Wed Oct 20, 2010 8:50 am Post subject: Engine Failure in a Yak-50

Great idea George.  

 

Mark

 



________________________________



From: owner-yak-list-server(at)matronics.com on behalf of George Coy

Sent: Wed 10/20/2010 10:16 AM

To: yak-list(at)matronics.com

Subject: RE: Engine Failure in a Yak-50






I would mention that when we did the Yak-52TW we had the factory reinforce

the front canopy bow. The plan being that if someone did an off field

landing and flipped the airplane that there would be some protection from

being crushed. It would bridge from the vertical stab to the canopy bow to

the nose cowl.



George Coy

CAS Ltd.

714 Airport Rd.

Swanton VT 05488

802-868-5633 off

802-363-5782 cell

george.coy(at)gmail.com

http://coyafct.com/

SKYPE george.coy

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