REFLECTOR: Still test flying...battling high CHT's

[Richard J. Gentil]

Hi Geoff,

My deflectors inside the plenum did nothing but the VG's in front of the NACA's helped. I have not tried inside the runners. 

Richard 

Sent from my iPhone 4 Classic

On Sep 9, 2012, at 8:08 PM, Geoff Gerhardt <geoff.gerhardt at gmail.com> wrote:

> All,
> 
> Just an update on my test flying.  I've got just over 9hrs in now.  I have been battling high CHT's, making a few changes.  I had a fuel flow imbalance that was causing some problems (hot #2) - I think it was a partially blocked injector.  I took all the injectors/lines out and cleaned them and balanced the flows (mixed and matched injectors until all injectors were putting out the same flow.  Now, in cruise, all cylinders are pretty close and reasonably cool (or, I guess, not overly hot).  Once I get to cruise, they all sit <380F.  But, on climb out, #3 gets way too hot (420F) forcing me to reduce power and bring the nose down so I'm climbing at <500FPM at ~60% power, 100kts.  But, once I get to cruise and can bring the nose down and get the speed up, it behaves.  Still the hottest, but it'll sit around 380F.  So, I'm thinking I have to work on my cooling plenums.  #4 will get hot too, but it doesn't get much over 400F.
> 
> Has anyone had success putting deflectors in the plenums to direct air flow to cyls 3/4?  Or, maybe VG's in the entrance of the runners to keep the airflow better attached to the bottom of the runner so it can turn the corner down to cool 3/4 (I have VG's before the NACAs)?
> 
> Part of the issue may be my cruise prop - I need to keep full power on to get a decent climb rate.
> 
> Thanks.
> 
> Geoff
> 
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