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Coolant overheating

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frans(at)paardnatuurlijk.
Guest

Posted: Thu Oct 29, 2009 1:40 pm Post subject: Coolant overheating

[quote:840d48a39a="kheindl"]

I have a trigear/912S with close to 300 hours, with no previous problems of this nature. For my last annual I decided

to change coolant (glycol 50/50) and oil, and all hoses and fuel lines. I had also made changes to improve airflow over 

the engine, at the same time reducing drag. I have since then removed those changes again, but this has made no difference.

On the contrary, the temperature seems to be even higher.

I just don't want to spill a lot of coolant all over the engine. One idea is to remove the coolant - I have a pump and I can

feed the extraction hose right down to the radiator - and then refilling the radiator first, and then the rest.

I will keep all informed.

[/quote:840d48a39a]



Found this post in the archive. I guess you have solved the problem by now, but I would be interested to hear what you had to do to fix it.



Fired up my Rotax recently, and now with 3 hours of intermittent running, I can finally keep it running at idle without overheating (that is, with the temperatures stabilizing at 115 Celcius). Quite an improvement, but of course I'm hoping to get further than this. If you found a reason why your Rotax overheated, it might well be worth checking to see if my Rotax has the same problem.



Frans

Visit -  www.EuropaOwners.org

kheindl(at)msn.com
Guest

Posted: Thu Oct 29, 2009 4:39 pm Post subject: Coolant overheating

  

Hi Frans C

  

 I just don't remember exactly what cured my overheat problems. One theory was that there was a leak on one of the hose clamps C which didn't show up with a cold engine C but would let out steam (and reduce pressure similar to a loose cap) when the engine was hot.

 Another was a possible airlock.

 Other changes I had made since then was to increase the air exit area C close the gills C reduce the round opening on the stbd side by 70% C and reduce the large naca scoop by 80%. More recently I replaced the large main opening with a in-flight variable flap further down and back from the original.  I want to cut drag as much as possible for when I switch to the long wings.

 I know that some or maybe most Europas have no cooling issues at all with a bog standard installation C so I hope that you can get that resolved. Of course the 914 is putting out more heat C and I don't know if you have that baffle which directs air over the cylinder heads. Is the thermostat accurate ?  The probe for mine is in one of the coolant hoses.

 You had made similar mods to your cowling C so that should have helped.

  

 Cheers C  Karl

  

  

 



 

 



  

[quote] Subject: Re: Coolant overheating

 From: frans(at)paardnatuurlijk.nl

 Date: Thu C 29 Oct 2009 23:37:42 +0200

 To: europa-list(at)matronics.com

 

 --> Europa-List message posted by: "Frans Veldman" <frans(at)paardnatuurlijk.nl>

 

 [quote:840d48a39a="kheindl"]

 I have a trigear/912S with close to 300 hours C with no previous problems of this nature. For my last annual I decided

 to change coolant (glycol 50/50) and oil C and all hoses and fuel lines. I had also made changes to improve airflow over 

 the engine C at the same time reducing drag. I have since then removed those changes again C but this has made no difference.

 On the contrary C the temperature seems to be even higher.

 I just don't want to spill a lot of coolant all over the engine. One idea is to remove the coolant - I have a pump and I can

 feed the extraction hose right down to the radiator - and then refilling the radiator first C and then the rest.

 I will keep all informed.

 [/quote:840d48a39a]

 

 Found this post in the archive. I guess you have solved the problem by now C but I would be interested to hear what you had to do to fix it.

 

 Fired up my Rotax recently C and now with 3 hours of intermittent running C I can finally keep it running at idle without overheating (that is C with the temperatures stabilizing at 115 Celcius). Quite an improvement C but of course I'm hoping to get further than this. If you found a reason why your Rotax overheated C it might well be worth checking to see if my Rotax has the same problem.

 

 Frans

 

 

 

 

 

 

 Visit - www.EuropaOwners.org

==

 

 

 

 		 	   		     	  Quote: 	
		  [b]

frans(at)paardnatuurlijk.
Guest

Posted: Fri Oct 30, 2009 12:57 am Post subject: Coolant overheating

Hi Karl,



 	  Quote: 	
		   Other changes I had made since then was to increase the air exit

 area, close the gills, reduce the round opening on the stbd side by

 70%, and reduce the large naca scoop by 80%.


	


The naca scoop is only for the 914. We build a closed cabinet around it,

where only the intake air filter resides. So the engine gets somewhat

"pressurized" air. The 914 doesn't use the naca scoop for anything else,

so you can safely scrap it on 912's.



 	  Quote: 	
		   More recently I replaced

 the large main opening with a in-flight variable flap further down

 and back from the original.


	


Any pics? 



I have the flap at the exit. Although I have not been flying, it seems

to work: can get the engine to overheat in a short time by closing it,

and  cool down again from that position when opening it.  In cruise

conditions my aim is to have roughly the same exit area as the inlet

area, so the velocity of the outgoing air is the same as the air around

it. Both the inlet and outlet have a diffuser. All to cut drag.

Closed off the gills. Added two naca inlets on top of the cowling with

the airflow aimed directly downwards onto the cylinders. This replaces

the two round inlets in the front which I intent to use for landing lights.



Now, as my engine runs very hot, I realise that my cooling mods are not

yet very convincing.  But I started with a conventional setup, and

the engine overheated in 7 minutes from a cold start. In the TCU the

parameters indicated that my engine has been running for less than 1

hour before they shipped it. At the moment I have 3 hours on it, and it

now runs considerably cooler than before. Water and oil reach almost

redline at the same moment, so I assume there is not an airlock

somewhere. Now I can idle indefinitely without touching the red lines, I

will run the engine somewhat more to see if that gets the temperatures

down further.



 	  Quote: 	
		   I know that some or maybe most Europas have no cooling issues at all

 with a bog standard installation, so I hope that you can get that

 resolved. Of course the 914 is putting out more heat, and I don't


	


As long as one does not exceed 80hp, the 914 shouldn't produce any more

heat than a 912. It is essentially a 912 but with a turbo bolted onto it.



 	  Quote: 	
		   know if you have that baffle which directs air over the cylinder

 heads.


	


No, unfortunately I didn't know about its existance when I bought and

installed the engine. But instead I have my naca inlets with the airflow

aimed directly on top of the cylinders. On the ground it doesn't help

much though, as there is not much prop wash in that area (but that is

also the problem with the factory inlets and the Rotax baffle).



 	  Quote: 	
		   Is the thermostat accurate ?


	


I have 4 CHT's and a coolant temperature gauge. They all agree with each

other.



Frans

steven.pitt2(at)ntlworld.
Guest

Posted: Fri Oct 30, 2009 2:05 am Post subject: Coolant overheating

I come to this subject a little late but I have a 'problem' with oil heating 

rather than coolant temperatures.

My 912s has always run on the cool side for the oil temperature (standard 

steam gauges) and on cooler Autumn days barely gets above 60dgrees. On take 

off I do climb to achieve a higher temperature to try to burn off any water 

that may be in the system.

I have heard of cowl flaps being used for temperature control but do not 

know of any fittments to Europas.

Can anyone help?

I do use Evans without any problems on that side.

Steve Pitt

G-SMDH 200 hours and still smiling

---

grahamsingleton(at)btinte
Guest

Posted: Fri Oct 30, 2009 2:24 am Post subject: Coolant overheating

Frans Veldman wrote:

Frans

It is generally noted that Lycosaurus type engines should never be run 

at low load when breaking in, it glazes the bores so that the rings do 

not bed in correctly. Rounded surface on the circumference perhaps? so 

they start to pump oil? I would think the same principle applies to Rotax.

Graham

 	  Quote: 	

 Hi Karl,

> Other changes I had made since then was to increase the air exit

> area, close the gills, reduce the round opening on the stbd side by

> 70%, and reduce the large naca scoop by 80%.

>     

 The naca scoop is only for the 914. We build a closed cabinet around it,

 where only the intake air filter resides. So the engine gets somewhat

 "pressurized" air. The 914 doesn't use the naca scoop for anything else,

 so you can safely scrap it on 912's.

> More recently I replaced

> the large main opening with a in-flight variable flap further down

> and back from the original.

>

frans(at)paardnatuurlijk.
Guest

Posted: Fri Oct 30, 2009 2:30 am Post subject: Coolant overheating

Steve Pitt wrote:

 	  Quote: 	
		   I come to this subject a little late but I have a 'problem' with oil

 heating rather than coolant temperatures.

 My 912s has always run on the cool side for the oil temperature

 (standard steam gauges) and on cooler Autumn days barely gets above

 60dgrees. On take off I do climb to achieve a higher temperature to try

 to burn off any water that may be in the system.

 I have heard of cowl flaps being used for temperature control but do not

 know of any fittments to Europas.

 Can anyone help?


	


Presuming you have an XS, the idea is simple: construct some sort of

cockpit controllable flap to close off the exit area of the radiator. I

changed the bottom of the cowling for this purpose, and put the whole

exit area on hinges, so if I close off the exit area of the radiator the

drag reduces as well (and because of the smaller exit area the air gets

accelerated and produces some propulsion). To control the system there

are of course a lot of possibilities: I use a small servo similar to the

trim servo because I found that the easiest and lightest way to do it.

Remember that this flap will be in the airstream and that you need some

way to lock the flap in the desired position, a servo will do that

automatically.



Keep in mind that it is easy to reduce the cooling of the Europa, but

the challenge is to do it in such a way that you get something in

return, i.e. a reduction of cooling drag. Blocking off part of the

radiator, or using a thermostat will solve your cooling problem, but

still give you the penalty of cooling drag.



I will post some pictures soon.



Frans

frans(at)paardnatuurlijk.
Guest

Posted: Fri Oct 30, 2009 2:43 am Post subject: Coolant overheating

Graham Singleton wrote:



 	  Quote: 	
		   It is generally noted that Lycosaurus type engines should never be run

 at low load when breaking in, it glazes the bores so that the rings do

 not bed in correctly. Rounded surface on the circumference perhaps? so

 they start to pump oil? I would think the same principle applies to Rotax.


	


Yes, that concerns me as well. It is however a bit difficult to apply

full power to an engine that with idle alone overheats within 7

minutes... Now the engine starts to behave a bit better, I will select a

cold morning and try to get it to run a higher power levels.



Frans

grahamsingleton(at)btinte
Guest

Posted: Fri Oct 30, 2009 2:57 am Post subject: Coolant overheating

Run at 60% until hot, then shut down and wait till it is cool before 

running again.  the time you can run will slowly increase as the rings 

break in.

(Lycoming experience, I think race bikes show the same characteristics

Graham



Frans Veldman wrote:

 	  Quote: 	
		  > they start to pump oil? I would think the same principle applies to Rotax

> Yes, that concerns me as well. It is however a bit difficult to apply

> full power to an engine that with idle alone overheats within 7

> minutes... Now the engine starts to behave a bit better, I will select a

> cold morning and try to get it to run a higher power levels.

>

> Frans

>

hurstkr(at)redzone.com.au
Guest

Posted: Fri Oct 30, 2009 3:38 am Post subject: Coolant overheating

Frans,



Graham beat me to the punch so as well as agreeing with what he has said, I 

would just add that before the rings are run in, there will be more blow-by 

which at least will heat the oil and I imagine, generally make the engine 

run hotter.  Remember too, that a new engine is usually much tighter than a 

used one which will also cause it to generate more heat.



Not that I can speak from experience, but I'm wondering if you might be 

better off getting the aircraft into the air where you can properly load the 

engine to run the rings in and at the same time generate more cooling from 

the airflow.  Once the rings are properly bedded in, the heating experience 

on the ground might be quite different from what it is now.



I still have to go through the run-up experience so I humbly speak with 

tongue in cheek.



Regards

Kingsley

grahamsingleton(at)btinte
Guest

Posted: Fri Oct 30, 2009 4:18 am Post subject: Coolant overheating

Kingsley Hurst wrote:

 	  Quote: 	
		   

 <hurstkr(at)redzone.com.au>



 Frans,



 Graham beat me to the punch so as well as agreeing with what he has said,



 I still have to go through the run-up experience so I humbly speak 

 with tongue in cheek.



 Regards

 Kingsley

Kingsley
	


First punch is not always the most effective, you put it better than I 

did Kingsley! Getting wooly in my dotage 

regards

Graham

frans(at)paardnatuurlijk.
Guest

Posted: Fri Oct 30, 2009 4:27 am Post subject: Coolant overheating

Kingsley Hurst wrote:



 	  Quote: 	
		   Not that I can speak from experience, but I'm wondering if you might be

 better off getting the aircraft into the air where you can properly load

 the engine to run the rings in and at the same time generate more

 cooling from the airflow.  Once the rings are properly bedded in, the

 heating experience on the ground might be quite different from what it

 is now.


	


That would be an ideal solution. However I presume that any test pilot

will want to see this thing running at full power on the ground for

several minutes, before taking it out for a test flight. So, I have at

least get to that stage. I haven't dare to test it yet, but I would be

surprised if I can run it for two minutes at full power at the ground

without overheating it.



Frans

pjeffers(at)talktalk.net
Guest

Posted: Fri Oct 30, 2009 5:24 am Post subject: Coolant overheating

Having carried out a number of first flights on 912 powered Europas I would

offer the following observations.

Prior to first flight I insist on carrying out at least a full power run for

2 minutes on the ground.  Full power meaning 5800 RPM (throttle full open,

RPM controlled by prop pitch).  If a fixed pitch prop then full throttle

will do. 

Such a run achieves two things. Firstly it demonstrates the engine

performance and fuel flow adequate to get the aircraft airborne and into a

safe downwind position.  Secondly it demonstrates adequate cooling to enable

flight without exceeding any limits. After shut down heat soakage from

engine to coolant may well cause the water to boil. Pressure is built up in

the cooling system and the system may well vent itself out of the water

header tank.  This demonstrates operation of the pressure relief valve and

integrity of all your joints. After the run (and cooling), top the system up

and check tighten all hoses.

During such a ground run I would expect the oil and water temperatures to

get very close to or equal to limits. Subsequent flights will demonstrate

that cooling is adequate and as the engine settles in will progressively

improve. Assuming no other problems the temperatures will continue to slowly

fall over the next 50 to 100 hours of running.

I hope this provides some guidance as to what to expect on early runs and

flights.



Pete Jeffers



--

topglock(at)cox.net
Guest

Posted: Fri Oct 30, 2009 6:24 am Post subject: Coolant overheating

Steve,



I had the same problem until I sealed the water cooler all the way 

around.  Apparently that lets less air through the duct for oil cooling. 

  Oil temps now average about 220 F. while water temps are down slightly.



Jeff - Baby Blue



Steve Pitt wrote:

[quote] 

 

 I come to this subject a little late but I have a 'problem' with oil 

 heating rather than coolant temperatures.

 My 912s has always run on the cool side for the oil temperature 

 (standard steam gauges) and on cooler Autumn days barely gets above 

 60dgrees. On take off I do climb to achieve a higher temperature to try 

 to burn off any water that may be in the system.

 I have heard of cowl flaps being used for temperature control but do not 

 know of any fittments to Europas.

 Can anyone help?

 I do use Evans without any problems on that side.

 Steve Pitt

 G-SMDH 200 hours and still smiling

 ---

hurstkr(at)redzone.com.au
Guest

Posted: Sat Oct 31, 2009 1:13 am Post subject: Coolant overheating

 	  Quote: 	
		   First punch is not always the most effective, you put it better than I did 

 Kingsley!


	


Not  so sure about putting it better Graham but about punches, when you are 

of my stature, you make sure you give in before they start flying!



Hope you and Joan are keeping well.



Cheers

Kingsley



do not archive

frans(at)paardnatuurlijk.
Guest

Posted: Wed Nov 11, 2009 12:43 pm Post subject: Coolant overheating

Graham Singleton wrote:

 	  Quote: 	
		   

 <grahamsingleton(at)btinternet.com>

 

 Run at 60% until hot, then shut down and wait till it is cool before

 running again.  the time you can run will slowly increase as the rings

 break in.


	


Decided today to run it without the cowling. That made a huge

difference! I could easily apply 60% power and also managed to make a 4

minute excursion to full power. I will repeat this a few times to let

the rings set.



Frans

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