Jabiru 2200 CHT

11 posts in this topic

Posted

I am a new Avid owner and the airplane has a Jabiru 2200 engine.  There is a CHT gauge in the cockpit, but no way that I have found to lean the engine.  Is there a purpose for the CHT with the Jabiru other than for leaning the fuel?  This from a mostly Lycoming and Continental engine guy.

Thanks,

Jim Bowerman N220AP

 

Share this post


Link to post
Share on other sites

Posted

Its just to let you know when to throttle back.

Share this post


Link to post
Share on other sites

Posted

OK, I know what the CHT gauge indicates, but what value or peak or ? will the CHT indicate when it is time to throttle back.

Thank you for the response,

Jim

Share this post


Link to post
Share on other sites

Posted (edited)

OK, I know what the CHT gauge indicates, but what value or peak or ? will the CHT indicate when it is time to throttle back.

Thank you for the response,

Jim

http://jabirupacific.com/pdf/2200ManualHyd.pdf

Looks like climb is 392 and cruise is 356. That info comes from page 13. If your cowl and ram air ducts are designed right you will never see those temps. Im lucky to see 300 on a hot day.

Edited by TJay

Share this post


Link to post
Share on other sites

Posted

Tjay,

Thanks for the information and for the manual download location.  Both are valuable.

Jim Bowerman N220AP

Share this post


Link to post
Share on other sites

Posted

What is the serial # of your engine?  JImChuk

Share this post


Link to post
Share on other sites

Posted

I am going to have to confess that I had my head in a dark smelly place when I first placed this query about my Avid having a CHT.  It doesn't.  What it really has is a Jabiru 2200 with an EGT gauge and a probe in each exhaust manifold, but NO mixture control.  Any ideas why this instrument would be installed under these conditions?  Is it normal to have it on this engine?

Sorry about the mistake, but thanks for any help,

Jim

Share this post


Link to post
Share on other sites

Posted

If the mixture is good, you probably don't have a need for the EGT gauge.  Same goes really for any of the engine gauges.  Problem of course is how do you know it's good without the gauge.  I have EGT and CHT on all four cylinders.  Plus an alarm if the readings go to high on my MGL engine monitor.  A 4 way switch switches from one cylinder to the next so I only see one cylinder at a time.  They pretty much stay where they are supposed to, so I don't look at them a whole lot.   I have about 500 hrs on my Jabiru 2200.  JImChuk

Share this post


Link to post
Share on other sites

Posted

Yes, that is my conclusion as well.  I am not going to change anything, just wanted to know if there was some special reason, other than monitoring, for the EGT installation since there was no way for the pilot to control the mixture.

Thanks,

Jim

Share this post


Link to post
Share on other sites

Posted

Jim:

RE: CHTs

I monitor all EGTs and CHTs.

EGTs tell what is happening in your engine NOW. CHTs tell how those readings are affecting your engine over time.

CHTs will tell you how much stress the engine is under.

RE: Mixture control

The ability to adjust mixture via Hackman-type device allows you to reduce fuel burn and CHTs at altitude.

Example: On my Jabiru 2200 powered Avid Flyer at 7500 MSL rich burn is 3.5 GPH at 2850 RPM. After leaning fuel burn is 2.5 GPH. Engine runs cleaner and more efficiently.

The Bing carb does not lean efficiently but it does lean a bit.

John M

 

Share this post


Link to post
Share on other sites

Posted


Ok, this is going to sound really bizarre, but, unless something has changed, you DO have a CHT gauge.  There should be a rotary switch over on the right side, labeled 1-4, to select the cylinder.  The CHT /tach gauge should be a combination gauge under the VSI..  Value of CHT is to insure you don't overheat the heads, and you can MANUALLY change the mixture on the bing for major altitude differences.  EGT (left and right) is likewise there to let you know that the settings are OK on the Carb mixture.  The Jab can have uneven mixture supplied to the different cylinders- there is info online that will tell you which way to twist the carb to even out the delivery, by getting the CHTs close across all cylinders....   Your dash *should* look a LOT like the attached picture...  :-)  But, things change...

 

Jack

Austin, TX

IMG_2154.JPG

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now