Matronics Email Lists :: View topic - 914 w/intercooler induction air heating

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

914 w/intercooler induction air heating

Matronics Email Lists Forum Index -> RotaxEngines-List

View previous topic :: View next topic

Author Message

pasj66

Joined: 28 Jan 2009
Posts: 7
Location: Gothenburg, Sweden (ESGI)

Posted: Wed Jan 28, 2009 12:25 pm Post subject: 914 w/intercooler induction air heating

Hi all,

I am searching for some info on the temperature difference between airbox temperature and ambient during flight. JAR 23.1093 states if the temperature rise is more than 56 deg C when ambient temperature is -1 deg C at 60 % power there is no need for carb heating. In JAR-VLA 1093 the temperature rise should be 38 deg C with the same conditions. Has anyone with a 914 w/intercooler done some flight tests? Installing carb heating is a bit of a hassle so I hope anyone have done these tests to find out whether it is necessary. If anyone can share their findings that would be most helpful.



Best regards

Patrik

(MCR R100 914 w/intercooler 85 % finished)

_________________
MCR R100, R914UL3 W/IC

Gilles.Thesee(at)ac-greno
Guest

Posted: Wed Jan 28, 2009 2:06 pm Post subject: 914 w/intercooler induction air heating

Patrick and all,

 	  Quote: 	
		   I am searching for some info on the temperature difference between airbox temperature and ambient during flight. JAR 23.1093 states if the temperature rise is more than 56 deg C when ambient temperature is -1 deg C at 60 % power there is no need for carb heating. In JAR-VLA 1093 the temperature rise should be 38 deg C with the same conditions. Has anyone with a 914 w/intercooler done some flight tests? Installing carb heating is a bit of a hassle so 

Remember those rules have been written by people used to Lyco/Conti 
	


aircooled engines, with hot air as the sole means of avoiding carb ice.

We are flying an MCR 4s with an intercooled 914. Due to our engine 

installation peculiarities, our carb temperatures are within the 40-50°C 

range in flight. Whatever the air temperature, remember ice cannot build 

up on warm metal.



But it all depends on your particular engine installation.

With a proper airbox around the air filter, it is no big deal to devise 

a warm air door into the engine compartment.

FWIW,



Best regards,

-- 

Gilles

http://contrails.free.fr

rparigor(at)suffolk.lib.n
Guest

Posted: Wed Jan 28, 2009 3:30 pm Post subject: 914 w/intercooler induction air heating

Hi Gilles"our carb temperatures are within the 40-50°C range in flight. Whatever the air temperature, remember ice cannot build up on warm metal."Curiosity question, what is your carb temperature when you pull power to a low power setting or idle and you let the wind turn propellor (turbo not doing much in the way of rammin and jammin / hence warming and the intercooler is bringing down any rise in temp caused by turbo closer to ambient)?Have you ever gotten carb ice?If yes did making some BTUs cure it?Thx.Ron Parigoris   [quote][b]

chunk(at)xtra.co.nz
Guest

Posted: Wed Jan 28, 2009 8:42 pm Post subject: 914 w/intercooler induction air heating

Hi guys,

  

 Apparently a 914 powered MCR generates more ambient heat in the engine  cowling than the 912 S powered MCR ULC that I have. I have attached a  temp. probe to a carburator body and it never rises above 25 degrees C  during what appears to be carb ice conditions. If the temp. ever starts to  fall below 19 degrees, (displayed on the panel) I know it is time to activate  carb heat. I leave it on until the temp. rises above 23 degrees again. As you  note, ice will not stick on warm metal.

  

 Here in New Zealand we sometimes have quite pronounced carb ice conditions.  After 3 such forced landing events without a carb heat facility I fitted a flap  to close off the outside ram air just to have some control over the  situation. It is now quite interesting watching the correlation between the  rising temp in the airbox, which I also moniter, and the temp of the carb body.  Takes a few minutes sometimes - but it is less stressful than looking for  somewhere to land with no noise up front!

  

 Regards,

 Evan Gardiner

  



I am using the Free version of SPAMfighterWe are a community of 5.9 million users fighting spam.SPAMfighter has rot have this message    [quote][b]

pasj66

Joined: 28 Jan 2009
Posts: 7
Location: Gothenburg, Sweden (ESGI)

Posted: Wed Jan 28, 2009 11:14 pm Post subject: Re: 914 w/intercooler induction air heating

Hi Gilles,

I have visited your web site quite often the last year during the assembly of our MCR. Very helpful and informative. Regarding carb heat the JAR specification has to be met somehow in order to get a type certificate, and the fact that Dynaero does not offer a carb heat option to their factory built 914 installations the pre certification flight tests must have shown that it was not needed. I am waiting for a mail from dynaero in this matter. In addition it is interesting to hear other peoples experiences.



Best regards

Patrik

_________________
MCR R100, R914UL3 W/IC

ptag.dev(at)tiscali.co.uk
Guest

Posted: Thu Jan 29, 2009 2:47 am Post subject: 914 w/intercooler induction air heating

Hi! Gilles.  

Happy New Year ...if not too late !  

I was concerned about carb. ice with an intercooler fitted to my 914 installation. Especially when the Intercooler manufacturers (Bell) were claiming 25deg temp drop in Winter and 20deg drop in Summer. I have a crude temperature sensor reduxed into a plastic hollow tube to the port carb throat and have never seen less than 6 deg Celsius. Even descending on low power settings through thin cloud formation from 10,000ft after the wind screen in my Europa began to frost over on the inside with minimal cabin heat facility.  

Whilst I do understand that carb ice conditions are very humidity and ambient temperature connected this has left me "fairly" confident that ice is not an issue ( I am reluctant to actually say that since next flight .!)  

However Rotax do recommend a carb heat facility even with a turbo fitted …but this may be sales justified or  more appropriate to tropical applications in real terms.  

My air filter is not of the air box type just a simple washable air canister clipped to the turbo intake.  

Regards  

Bob Harrison G-PTAG Europa Kit 337 Now with Rotax 914.  

   

--

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Jan 30, 2009 9:04 am Post subject: 914 w/intercooler induction air heating

Hi Ron and all,

 	  Quote: 	
		  

 Curiosity question, what is your carb temperature when you pull power 

 to a low power setting or idle and you let the wind turn propellor 

 (turbo not doing much in the way of rammin and jammin / hence warming 

 and the intercooler is bringing down any rise in temp caused by turbo 

 closer to ambient)?



According to my test curves, carb temps during descend never went below 
	


40Celsisus on a cold day (OAT 5Celsius ground, -2 Celsius at altitude).

Of course, low power setting does not last long with our aircraft.



Due to the turbo running at dull red temperature just inches below the 

carbs, temps can stay relatively high in a close fitting cowling.

 	  Quote: 	
		  



 Have you ever gotten carb ice?




	


Never noticed anything, although I flew the aircraft in rain and drizzle.

 	  Quote: 	
		  



 If yes did making some BTUs cure it?



Due to air low thermal capacity, charge air temperature doesn't play 
	


much role compared to the red hot exhausts and turbo case.



Best regards,

-- 

Gilles

http://contrails.free.fr

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Jan 30, 2009 10:39 am Post subject: 914 w/intercooler induction air heating

Patrick



Thank you for your kind words.



 	  Quote: 	
		   Regarding carb heat the JAR specification has to be met somehow in order to get a type certificate, and the fact that Dynaero does not offer a carb heat option to their factory built 914 installations the pre certification flight tests must have shown that it was not needed. I am waiting for a mail from dynaero in this matter. In addition it is interesting to hear other peoples experiences.


	


As you may have noticed, our engine installation is quite different from 

that of Dyn'Aero. We had to send a report with our carb temp number to 

the certification authorities to get our certificate of airworthiness.

During ground tests, we had thick freezing fog to the point I was scared 

to taxi on the apron lest we collide with a building, a car or an airplane.

After some time ground running at high power setting, we noticed a 

slight vibration up front (no power loss nor MP variation). After 

stopping the engine, we discovered that the whole airplane was covered 

with frost in the prop wash, the air intake lips as well as the prop 

leading edges were covered with several millimeter clear ice.



But the carb temps were as usual, and the vibration was attributed to 

the ice buildup on the prop blades.



Best regards,

-- 

Gilles

http://contrails.free.fr

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Jan 30, 2009 12:58 pm Post subject: 914 w/intercooler induction air heating

Hi Bob,

Best wishes for 2009.



 	  Quote: 	
		   I was concerned about carb. ice with an intercooler fitted to my 914 

 installation. Especially when the Intercooler manufacturers (Bell) 

 were claiming 25deg temp drop in Winter and 20deg drop in Summer.



This about what we get with our installation, with an optimized 
	


intercooler inlet diffuser, and clean air exit nozzle.

If the diffuser is not optimal, or the intercooler cooling air exit has 

any obstruction the efficiency will be much less.



 	  Quote: 	
		   I have a crude temperature sensor reduxed into a plastic hollow tube 

 to the port carb throat and have never seen less than 6 deg Celsius. 

 Even descending on low power settings through thin cloud formation 

 from 10,000ft after the wind screen *_in_* my Europa began to frost 

 over on the *_inside_* with minimal cabin heat facility.



 Whilst I do understand that carb ice conditions are very humidity and 

 ambient temperature connected this has left me "fairly" confident that 

 ice is not an issue ( I am reluctant to actually say that since next 

 flight ..!)



Interesting data. We are no longer monitoring carb temps.
	


Best regards,

-- 

Gilles

http://contrails.free.fr

pasj66

Joined: 28 Jan 2009
Posts: 7
Location: Gothenburg, Sweden (ESGI)

Posted: Sun Feb 01, 2009 2:24 am Post subject: Re: 914 w/intercooler induction air heating

Thanks everyone for your informative replies. The experience shows that icing is not a problem. The thing is to convince the authorities. I got a response from DynAero and they are a bit secretive and will only communicate the flight test results with the local CAA. I am a bit paranoid having our project grounded due to red tape so maybe a more proactive approach is to include the same measurements as you, Gilles, in our flight test program. How did you perform the measurements? Measurement points, power settings, ambient temperatures etc. What info did convince the authorities? Could you please describe the setup that would be most helpful. Either in this thread or you can mail me directly.



Best regards

Patrik

_________________
MCR R100, R914UL3 W/IC

Thomas

Joined: 04 Feb 2009
Posts: 2

Posted: Thu Feb 05, 2009 2:17 am Post subject: Re: 914 w/intercooler induction air heating

Hallo,my name is Thomas and I'm a proud owner of a Dynaero 4S with 914.

I'm looking forward to install an intercooler .I'm not sure if it gives anything to me because I'm satisfied with the performance until 8.000ft.

I would like to know the advantages of the intercooler up to 16.000ft.

Thanks for responses

Display posts from previous:

	Matronics Email Lists Forum Index -> RotaxEngines-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum