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surging engine on take-off

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kbcarpenter(at)comcast.ne
Guest

Posted: Sat May 05, 2007 5:02 pm Post subject: surging engine on take-off

Yesterday taking off, the engine surged as the turbo  kicked in it went up to 5700 RPM then dropped back into the 4800 range.  I  tried several runs but aborted the take-off as it continues to surge.   Checked the prop governor and it checked out as functioning correctly.;   Took the cowl off and the turbo arm seems to cycle correctly when the master  turned on and the throttle cycled.  Tied the plane down and ran it up to  5700 rpm.  It did not surge at all.  

 Any idea?  I have not tried to fly it again  yet.

 Ken Carpenter

 N 9XS   914 Mono at 430 hours  TT

   [quote][b]

SPurpura(at)aol.com
Guest

Posted: Sat May 05, 2007 6:06 pm Post subject: surging engine on take-off

How did your fuel flow numbers look?



See what's free at AOL.com. 

  [quote][b]

rehn(at)rockisland.com
Guest

Posted: Sat May 05, 2007 8:05 pm Post subject: surging engine on take-off

Ken  

Changes in boost can be often caused by basic engine problems. I would check  

Manifold leaks or restrictions  

Fuel system  

Air pressure hoses and connections including the small vacuum lines and connectors  

TCU and waste gate   

Again, I would carefully check the basics, chances are the turbo itself is OK.  

Good luck  

   

Jerry  

         

  

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of ken carpenter

 Sent: Saturday, May 05, 2007 5:44 PM

 To: europa-list(at)matronics.com

 Subject: surging engine on take-off  

  

     

Yesterday taking off, the engine surged as the turbo kicked in it went up to 5700 RPM then dropped back into the 4800 range.  I tried several runs but aborted the take-off as it continues to surge.  Checked the prop governor and it checked out as functioning correctly.;  Took the cowl off and the turbo arm seems to cycle correctly when the master turned on and the throttle cycled.  Tied the plane down and ran it up to 5700 rpm.  It did not surge at all.    

    

Any idea?  I have not tried to fly it again yet.  

    

Ken Carpenter  

    

N 9XS   914 Mono at 430 hours TT  

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        [quote][b]

Gilles.Thesee(at)ac-greno
Guest

Posted: Sun May 06, 2007 12:13 am Post subject: surging engine on take-off

ken carpenter a écrit :

 	  Quote: 	
		   Yesterday taking off, the engine surged as the turbo kicked in it went 

 up to 5700 RPM then dropped back into the 4800 range.  I tried several 

 runs but aborted the take-off as it continues to surge.  Checked the 

 prop governor and it checked out as functioning correctly.;  Took the 

 cowl off and the turbo arm seems to cycle correctly when the master 

 turned on and the throttle cycled.  Tied the plane down and ran it up 

 to 5700 rpm.  It did not surge at all. 

 Any idea?  I have not tried to fly it again yet.


	


Ken,



Of course this may be the first thing you checked, but an incorrect 

rigging of the throttles may lead to boost irregularities when in the 

100/115 % throttle opening range.

What you are describing reminds me of what COULD happen if the throttles 

are not in the full 115% position, and are stuck somewhere between about 

108 and 115%.

Do you have the required 100% gate on the throttle lever ?



Best regards,

Gilles

http://contrails.free.fr

kbcarpenter(at)comcast.ne
Guest

Posted: Sun May 06, 2007 7:04 am Post subject: surging engine on take-off

The fuel pressure was constant  around 24 with both pumps on.  The hoses look attached and in good shape.  The throttle lines are as they have been for four years and 430 hours.  I do not have a stop for the 100 percent power but have a manifold guage which I did not look at.  

 It puzzles me that the ground run-up did not reproduce the surg.

 ken  

  

 [quote]-------------- Original message -------------- 

From: Gilles Thesee <Gilles.Thesee(at)ac-grenoble.fr> 



[quote] --> Europa-List message posted by: Gilles Thesee 

 

 ken carpenter a écrit : 

 > Yesterday taking off, the engine surged as the turbo kicked in it went 

 > up to 5700 RPM then dropped back into the 4800 range. I tried several 

 > runs but aborted the take-off as it continues to surge. Checked the 

 > prop governor and it checked out as functioning correctly.; Took the 

 > cowl off and the turbo arm seems to cycle correctly when the master 

 > turned on and the throttle cycled. Tied the plane down and ran it up 

 > to 5700 rpm. It did not surge at all. 

 > Any idea? I have not tried to fly it again yet. 

 

 Ken, 

 

 Of   course  ======  [quote][b]

garrys(at)tampabay.rr.com
Guest

Posted: Sun May 06, 2007 7:31 am Post subject: surging engine on take-off

Ken,  this may not apply to you but I have a  Whirlwind constant speed prop with a Jihostra hydraulic prop governor.  If  my engine oil is not fully warmed up, the prop governor will not hold a constant  pitch.  Rather, it will change pitch back and forth causing an RPM surge up  and down.  If the oil is at normal operating temperatures, no  problem.  It's a long shot, but this may apply to you.  Good luck  sorting this out.

  

 Garry Stout

 914 Tri,  Tampa Florida

  

 [quote]   ---

erichdtrombley(at)juno.co
Guest

Posted: Sun May 06, 2007 8:21 am Post subject: surging engine on take-off

Ken, 

I would double check the prop governor.  Especially since you stated the problem did not occur during the static run up.  Not knowing what prop you have, is it possible to set the pitch manually (not rpm)?  If the prop is an electric controlled unit, while the engine is off adjust/set the pitch to approximately 22 deg and then pull the circuit breaker.  Now you have a fix pitch prop, effectively isolating the governor.  Perform a static ground run up and verify engine performance.  With the prop isolated any surging noticed during the take-off roll can then be attributed to the engine. 

If problem still persists, check throttle potentiometer for correct resistances.  As you are aware the turbo will surge between 108-110% throttle position.   

Also, you can always isolate the turbo.  This is a little more difficult since the default position of the waste gate is fully closed.  In order to bypass the turbo the waste gate must be manually set full open.  This can be done one of two ways.  The first and simplest, is to cycle the TCU, and when the waste gate is fully open, electrically isolate the servo motor (two pole switch installed per Rotax manual).  This is a two person activity, as one will need to watch the waste gate cycle and call out the moment it is fully open so that the person in the cockpit can isolate the servo motor.  The second method would require you to disconnect the servo cable at the servo motor, fully opening the waste gate.  Of course you will still need to electrically isolate the servo motor.   Next perform a ground run up and verify you do not exceed max RPM at full throttle.  If problem persists during take-off run abort take-off. 

Other checks of the turbo system, ie pressure sensors, 3-way solenoid valve, etc. can also be made with relative ease. 

Finally, you mentioned a drop in RPM from 5700 to 4800, do you recall what the manifold pressure was at the time? 

Good luck.   

Erich Trombley

N28ET, Classic Mono 914 

  



Time: 06:02:04 PM PST US

From: "ken carpenter" <kbcarpenter(at)comcast.net>

Subject: Europa-List: surging engine on take-off



Yesterday taking off, the engine surged as the turbo kicked in it went 

up to 5700 RPM then dropped back into the 4800 range.  I tried several 

runs but aborted the take-off as it continues to surge.  Checked the 

prop governor and it checked out as functioning correctly.;  Took the 

cowl off and the turbo arm seems to cycle correctly when the master 

turned on and the throttle cycled.  Tied the plane down and ran it up to 

5700 rpm.  It did not surge at all.  

Any idea?  I have not tried to fly it again yet.

Ken Carpenter

N 9XS   914 Mono at 430 hours TT



   [quote][b]

Gilles.Thesee(at)ac-greno
Guest

Posted: Sun May 06, 2007 11:50 am Post subject: surging engine on take-off

Ken,



 	  Quote: 	
		    The throttle lines are as they have been for four years and 430 

 hours.  I do not have a stop for the 100 percent power


	


So the throttle cables are ruled out.

Nevertheless, the absence of the required 100% gate reminds me of what I 

have seen happen on a few occasions : when advancing the throttle at 

takeoff, the pilot fails to push it all the way, at leaves it in the 

100-115 % sector where Rotax advises that turbo operation is instable. 

And indeed, the result was "attention getting" power surges 

Could this have happened ?



 	  Quote: 	
		   but have a manifold guage which I did not look at.

Too bad, as the reading could have helped discriminate between 
	


governor/prop and engine trouble.

It is good practice to monitor the two gauges during the takeoff run : I 

always make sure the RPM are 5800, and manifold pressure 39.9 in Hg. 

Some pilots reported a stuck waste gate, or a runaway prop governor.



All the best with your investigations,

Best regards,

Gilles

http://contrails.free.fr

Rschultz5(at)houston.rr.c
Guest

Posted: Sun May 06, 2007 6:04 pm Post subject: surging engine on take-off

Ken,  

   

This sounds a lot like the problem I had coming back from Oshkosh last year. My problem was surging while in the air and the engine seemed to always work on the ground. My problem was a plugged static pressure sender going to the TCU control circuit. Problems like this can be caused by the airbox or static pressure sensors or a leak in anyone of those little black hoses. I pulled each off house during troubleshooting my problem and used a small syringe to pressure them up in some soapy water to look for pin hole leaks. My problem ended when I pulled the static pressure sensor and found the end block with a rubber cap the painter had put on to keep out the dist and overspray.  

   

Just a thought for other places to look for your problem.  

   

Rich Schultz  

N262AE  

         

  

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of ken carpenter

 Sent: Saturday, May 05, 2007 7:44 PM

 To: europa-list(at)matronics.com

 Subject: surging engine on take-off  

  

     

Yesterday taking off, the engine surged as the turbo kicked in it went up to 5700 RPM then dropped back into the 4800 range.  I tried several runs but aborted the take-off as it continues to surge.  Checked the prop governor and it checked out as functioning correctly.;  Took the cowl off and the turbo arm seems to cycle correctly when the master turned on and the throttle cycled.  Tied the plane down and ran it up to 5700 rpm.  It did not surge at all.    

    

Any idea?  I have not tried to fly it again yet.  

    

Ken Carpenter  

    

N 9XS   914 Mono at 430 hours TT  

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wdaniell(at)etb.net.co
Guest

Posted: Mon May 07, 2007 1:58 am Post subject: surging engine on take-off

Remember the AeroPeru 757 that crashed into the ocean because the tape the painted had put over the static ports had not been removed?  

Will  

         

  

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

 Sent: Sunday, May 06, 2007 21:00

 To: europa-list(at)matronics.com

 Subject: RE: surging engine on take-off  

  

   

Ken,  

   

This sounds a lot like the problem I had coming back from Oshkosh last year. My problem was surging while in the air and the engine seemed to always work on the ground. My problem was a plugged static pressure sender going to the TCU control circuit. Problems like this can be caused by the airbox or static pressure sensors or a leak in anyone of those little black hoses. I pulled each off house during troubleshooting my problem and used a small syringe to pressure them up in some soapy water to look for pin hole leaks. My problem ended when I pulled the static pressure sensor and found the end block with a rubber cap the painter had put on to keep out the dist and overspray.  

   

Just a thought for other places to look for your problem.  

   

Rich Schultz  

N262AE  

         

  

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of ken carpenter

 Sent: Saturday, May 05, 2007 7:44 PM

 To: europa-list(at)matronics.com

 Subject: surging engine on take-off  

  

     

Yesterday taking off, the engine surged as the turbo kicked in it went up to 5700 RPM then dropped back into the 4800 range.  I tried several runs but aborted the take-off as it continues to surge.  Checked the prop governor and it checked out as functioning correctly.;  Took the cowl off and the turbo arm seems to cycle correctly when the master turned on and the throttle cycled.  Tied the plane down and ran it up to 5700 rpm.  It did not surge at all.    

    

Any idea?  I have not tried to fly it again yet.  

    

Ken Carpenter  

    

N 9XS   914 Mono at 430 hours TT  

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