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Question for 914 users

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kingsnjan(at)westnet.com.
Guest

Posted: Thu Nov 08, 2012 8:21 pm Post subject: Question for 914 users

At what stage during the takeoff roll do you see full boost please?



Another way of putting it ....... How long after the throttle is at 115% do you see full boost?



Thanks in anticipation



Kingsley

bill.sue(at)orcon.net.nz
Guest

Posted: Fri Nov 09, 2012 1:55 am Post subject: Question for 914 users

Kingsley,



I will time it in the morning and tell you.



Cheers



XSMono 914 Airmaster

1020hrs

Sue and Bill Sisley

On 9/11/2012 5:20 p.m., Kingsley Hurst wrote:

 	  Quote: 	
		   



 At what stage during the takeoff roll do you see full boost please?



 Another way of putting it ....... How long after the throttle is at 115% do you see full boost?



 Thanks in anticipation



 Kingsley

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Nov 09, 2012 6:39 pm Post subject: Question for 914 users

Kingsley Hurst a écrit :

 	  Quote: 	
		   



 At what stage during the takeoff roll do you see full boost please?



 Another way of putting it ....... How long after the throttle is at 115% do you see full boost?



   


	


Hi Kingsley,



I'd say about 2 to 3 seconds. We do not bang the throttle, but rather 

advance it steadily in 2 seconds.

Takeoff takes place in about 10 seconds.



Best regards,

-- 

Gilles

http://contrails.free.fr

bill.sue(at)orcon.net.nz
Guest

Posted: Fri Nov 09, 2012 9:14 pm Post subject: Question for 914 users

Kingsley,



Two New Zealand 914 drivers checked this for you today and we both got 

the same result at 5 seconds.



Regards from across the Tasman.



Bill

MonoXS 914 Airmaster.

Sue and Bill Sisley

On 10/11/2012 3:38 p.m., Gilles Thesee wrote:

 	  Quote: 	
		   

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



 Kingsley Hurst a écrit :

> 

> <kingsnjan(at)westnet.com.au>

>

> At what stage during the takeoff roll do you see full boost please?

>

> Another way of putting it ....... How long after the throttle is at 

> 115% do you see full boost?

>



 Hi Kingsley,



 I'd say about 2 to 3 seconds. We do not bang the throttle, but rather 

 advance it steadily in 2 seconds.

 Takeoff takes place in about 10 seconds.



 Best regards,

kingsnjan(at)westnet.com.
Guest

Posted: Sat Nov 10, 2012 12:22 am Post subject: Question for 914 users

Bob, Gilles and Bill



Many thanks for your respective inputs. 



On takeoff I sometimes don't see full boost until I'm well and truly airborne. (Not that I watch it every time). I have always suspected that the boost on our aircraft has been a bit slow to rise. 



The waste gate cycles freely, I see 34" MAP at 100% throttle position,  I'm getting 5700 RPM on less than full boost and the turbo spins freely. 



Now that you have answered my question and I know what to expect, I shall read up on the manual. 



If anybody has any ideas what can cause this I am receptive to any suggestions. 



Thanks again fellows. 



Kingsley

Remi Guerner

Joined: 14 Dec 2010
Posts: 284

Posted: Mon Nov 12, 2012 12:34 am Post subject: Re: Question for 914 users

Kingsley,

It seems your wastegate takes more time than normal to move to its position. This may be caused by some undesirable friction in the system. I would first investigate this possible cause. I suggest you disconnect the waste gate bowden cable at both ends and pull it back and forth. Move the waste gate lever back and forth. Both should move easily. If they donâ€™t, some cleaning and lubrication should solve the problem.

Please let us know your findings. Good luck.

Remi

pestar

Joined: 11 Apr 2007
Posts: 61
Location: Auckland, New Zealand

Posted: Mon Nov 12, 2012 12:30 pm Post subject: Re: Question for 914 users

As the other New Zealand 914 user that Bill refers to I add a little advice that may help.



You state you are only seeing 34 ins, that is what you get when the TCU is not working.  How do I know, I took off the other day with the TCU switched off and noted that I only pulled about 33 in manifold but was still getting full rpm, 5780 in my case.



This makes sense and though I do not suggest taking off with the TCU switched off it can be tried and would be a good pointer to see if your TCU is working.  That is apart from the usual checks to see if the servo is cycling.



Cheers Peter

_________________
Peter Armstrong
Auckland, New Zealand
DynAero MCR-4S (Do not shoot me Smile

kingsnjan(at)westnet.com.
Guest

Posted: Mon Nov 12, 2012 2:39 pm Post subject: Question for 914 users

Peter,



I eventually get 38" at 115% throttle setting. I get 34" at 100% throttle on the climb and it maintains 34" to 12,000 ft so I assume the TCU must be working. The TCU cycles perfectly on turn on. 



Having said that, I can certainly try a T/O with the TCU turned off to observe what happens. 



I need to have a fly behind another 914 in case my problem is only imaginary. 



Thank you for your help. 



Kingsley



Sent from my iPhone



On 13/11/2012, at 6:30 AM, "pestar" <peter(at)reivernet.com> wrote:



 	  Quote: 	
		   

 

 As the other New Zealand 914 user that Bill refers to I add a little advice that may help.

 

 You state you are only seeing 34 ins, that is what you get when the TCU is not working.  How do I know, I took off the other day with the TCU switched off and noted that I only pulled about 33 in manifold but was still getting full rpm, 5780 in my case.

 

 This makes sense and though I do not suggest taking off with the TCU switched off it can be tried and would be a good pointer to see if your TCU is working.  That is apart from the usual checks to see if the servo is cycling.

 

 Cheers Peter

 

 --------

 Peter Armstrong

 Auckland, New Zealand

 DynAero MCR-4S (Do not shoot me  ).

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=387706#387706

kingsnjan(at)westnet.com.
Guest

Posted: Mon Nov 12, 2012 2:48 pm Post subject: Question for 914 users

Remi,



Observing the waste gate lever and cable during the TCU test, it all appears  to be nice and free. Notwithstanding, I shall check the cable as you describe. 



Thank you for taking the time to assist. 



Kingsley



Sent from my iPhone



On 12/11/2012, at 6:34 PM, "Remi Guerner" <air.guerner(at)orange.fr> wrote:



 	  Quote: 	
		   

 

 Kingsley,

 It seems your wastegate takes more time than normal to move to its position. This may be caused by some undesirable friction in the system. I would first investigate this possible cause. I suggest you disconnect the waste gate bowden cable at both ends and pull it back and forth. Move the waste gate lever back and forth. Both should move easily. If they donâ€™t, some cleaning and lubrication should solve the problem.

 Please let us know your findings. Good luck.

 Remi

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=387667#387667

garrys(at)tampabay.rr.com
Guest

Posted: Mon Nov 12, 2012 4:29 pm Post subject: Question for 914 users

Not sure how you got 33 ins MP without turbo boost.  Nominal ambient

pressure at sea level is 29.92 ins.  You need turbo boost to achieve

something higher.



Garry Stout

--

pestar

Joined: 11 Apr 2007
Posts: 61
Location: Auckland, New Zealand

Posted: Mon Nov 12, 2012 7:46 pm Post subject: Re: Question for 914 users

It is because I live in the Southern Hemisphere and do not get impacted by Northern Hemisphere FUD.  ('')



Seriously I questioned that as well as what you say is correct however that is what my manifold pressure was reading on my EFIS. 



Cheers Peter

_________________
Peter Armstrong
Auckland, New Zealand
DynAero MCR-4S (Do not shoot me Smile

kingsnjan(at)westnet.com.
Guest

Posted: Mon Nov 12, 2012 8:10 pm Post subject: Question for 914 users

Gary,



On the 914, even with the waste gate fully open, not all of the exhaust gas bypasses the turbo hence there is still some boost. According to the manual, with a fully open waste gate, the engine will produce 70 Kw (approx 93 HP) instead of the 80 HP the same engine would produce if the turbo charger was removed. 



Regards

Kingsley



Sent from my iPhone



On 13/11/2012, at 10:28 AM, "Garry Stout" <garrys(at)tampabay.rr.com> wrote:



[quote] 

 

 Not sure how you got 33 ins MP without turbo boost.  Nominal ambient

 pressure at sea level is 29.92 ins.  You need turbo boost to achieve

 something higher.

 

 Garry Stout

 

 

 --

conrad

Joined: 07 Feb 2007
Posts: 16
Location: Banbury. UK

Posted: Tue Nov 13, 2012 12:32 am Post subject: Re: Question for 914 users

*Warning*

Do not attempt to take off with the TCU disabled. If the wastegate is fully closed when the TCU is powered down you will end up over boosting your engine with the possibility of twisting a crankshaft or burning a piston. 

Get someone who knows about the 914 & can interrogate the TCU to take a look at it.

 	  kingsnjan(at)westnet.com. wrote: 	
		  Peter,



Having said that, I can certainly try a T/O with the TCU turned off to observe what happens. 



	
[/quote]

kingsnjan(at)westnet.com.
Guest

Posted: Tue Nov 13, 2012 2:51 am Post subject: Question for 914 users

Conrad,

Thank you very much for the sage advice. Just thinking....... I don't really need to know what happens!

Cheers

Kingsley

Sent from my iPhone

On 13/11/2012, at 6:32 PM, "conrad" <conrad(at)conairsports.co.uk> wrote:

 	  Quote: 	

 *Warning*

 Do not attempt to take off with the TCU disabled. If the wastegate is fully closed when the TCU is powered down you will end up over boosting your engine with the possibility of twisting a crankshaft or burning a piston 

 kingsnjan(at)westnet.com. wrote:

> Peter,

> 

> Having said that, I can certainly try a T/O with the TCU turned off to observe what happens.

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=387748#387748

Gilles.Thesee(at)ac-greno
Guest

Posted: Tue Nov 13, 2012 3:00 am Post subject: Question for 914 users

Kingsley Hurst a écrit :

 	  Quote: 	
		   



 Conrad,



 Thank you very much for the sage advice. Just thinking....... I don't really need to know what happens!

   


	


Kingsley,



Just to make sure. Have you checked that the throttle cables do respond 

correctly to the throttle lever movements ?

IIRC, there have been some instances of cables buckling instead of 

sliding in their outer cases when one relies only on springs to open the 

butterflies in the carburettors.



To prevent this situation, our airplanes are equipped with solid piano 

wire 'cables' providing some push-pull action. The carb springs are just 

there for peace of mind.



FWIW,

Best regards,

-- 

Gilles

http://contrails.free.fr

kingsnjan(at)westnet.com.
Guest

Posted: Tue Nov 13, 2012 8:07 pm Post subject: Question for 914 users

Gilles,



Thank you again. Yes the levers on the carbs move in unison no matter how fast the throttle lever is advanced. The whole operation is very smooth and fluent.



I'm no expert on any of this stuff I can assure you but I would expect the engine not to run smoothly if a throttle cable was to lag the throttle movement. 



The engine runs like a sewing machine and my only observation is that the MAP seems slower to rise than expected be it true or imaginary!  Hence my dilemma.



Best regards

Kingsley



Sent from my iPhone



On 13/11/2012, at 9:00 PM, Gilles Thesee <Gilles.Thesee(at)ac-grenoble.fr> wrote:



 	  Quote: 	
		   

 

 Kingsley Hurst a Ã©crit :!

> 

 

 Kingsley,

 

 Just to make sure. Have you checked that the throttle cables do respond correctly to the throttle lever movements ?

 IIRC, there have been some instances of cables buckling instead of sliding in their outer cases when one relies only on springs to open the butterflies in the carburettors.

 

 To prevent this situation, our airplanes are equipped with solid piano wire 'cables' providing some push-pull action. The carb springs are just there for peace of mind.

 

 FWIW,

 Best regards,

 -- 

 Gilles

 http://contrails.free.fr

Gilles.Thesee(at)ac-greno
Guest

Posted: Wed Nov 14, 2012 4:20 am Post subject: Question for 914 users

Kingsley Hurst a Ã©crit :

 	  Quote: 	
		    my only observation is that the MAP seems slower to rise than expected be it true or imaginary!  Hence my dilemma.

   


	


What about the MAP lines, water trap, restriction, etc. ?



Best regards,

-- 

Gilles

http://contrails.free.fr

kingsnjan(at)westnet.com.
Guest

Posted: Mon Nov 19, 2012 1:57 pm Post subject: Question for 914 users

Hello Gilles,



Sorry for the delay in replying. 



I hadn't considered what you have suggested thanks and only got to checking it out two days ago. 



The line from the equaliser tube to the pressure sensor has a filter which was wrapped in a heat insulating mat.  This prevented casual observation of the state of the filter. On removing this covering I found the filter saturated with a brown sludge which I assume was stale condensate of fuel. When I blew through the line (with my mouth) there was a lot of restriction as you can imagine and I was thinking "thanks Gilles", you were right on the ball!



I did over two hours flying yesterday after fitting a new filter in a more elevated position and guess what? MAP readings on take-offs are identical to what they were before. (head now shaking!)



Because the engine is running so nicely, I have decided to let sleeping dogs lie. There is no point trying to fix something if one is not sure it is 'broke'!



Thanks again for your thoughts Gilles. 



Best regards



Kingsley



Sent from my iPhone



On 14/11/2012, at 10:19 PM, Gilles Thesee <Gilles.Thesee(at)ac-grenoble.fr> wrote:



 	  Quote: 	
		   What about the MAP lines, water trap, restriction, etc. ?

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