REFLECTOR: CHT's
Rene Dugas
dugasd at bellsouth.net
Mon Oct 19 18:16:59 CDT 2009
IO-540 260 hp
Rene'
My NACA's are 1 inch wider than recommended by the factory 9 years ago.
Second plenum. First exploded when I started the engine without the plenum
bolted down and caught in prop. Not a piece was bigger than 4 x 4 inches. I
have the slip joint half way up rails with about 1/8th inch opening. No
seal has ever been needed.
RD
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Derrick
Sent: Monday, October 19, 2009 2:25 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: CHT's
Rene, what engine are you running?
here's an early picture of my plenum.
http://tnstaafl.net/canards/img134.jpg
it was from the factory for a 550, close enough for a 520. The attachment
has changed but the overall shape is identical.
Scott
Rene Dugas wrote:
> I don't know what your naca to plenum looks like but mine is attached
> and no diverter was needed. All my CHT's are within 20 degrees.
> Hope it helps somehow.
> Rene'
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> On Behalf Of Scott Derrick
> Sent: Sunday, October 18, 2009 3:10 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: REFLECTOR: CHT's
>
> Flew this morning after plugging holes in the TCM/Cessna supplied
> "between cylinder baffles". I should have made my own, because the
> stock baffles have huge holes in them. They also don't wrap up around
> the sides of the cylinders for optimal cooling flow. I may try to
> tighten things up a bit more but it will require me to remove all the
> injection plumbing, spark plug wiring and some other stuff..
>
> Also adjusted the fuel map and smoothed out a few bumps in the oil
> cooler exit duct.
>
> The CHT's are really coming into a comfortable range. Cruising at 165
> KTAS(low power setting) they all stay below 360, but increasing power
> to above 200 KTAS and #2 climbed to 395, #1was about 365, the rest
> were all below 330. I'm mostly concerned with #2 but would like to
> see
> #1 more inline with the other 4 as well.
>
> I'm debating installing some kind of diverter(s) inside the plenum to
> direct more air onto #1 & #2. Anybody do that to lower CHT's with
> success? How did you do it? Got pictures? Controlling air movement
> is such a funny thing, sometimes what seems logical or intuitive is
> exactly the wrong thing to do!
>
> The fuel map is as good as I will be able to get it, until I get the
> new prop. At least I am not running at peak EGT in RPMs above 2200 now.
> That helped the temps a whole lot.
>
> Now to getting the oil temp down some more. Right now I am not running
> the fan on the secondary cooler as I see it as a summer time auxiliary
cooler.
> With OAT in the 60's I shouldn't need it. The oil temps were OK, but
> a bit on the high side at a low power cruise speed of 165KTAS.
> about 210F, but as soon as I fire-walled the throttle it started to
> come up and seemed to stabilize at around 230, though I didn't stay at
> that power setting more than a couple of minutes. With the IO360 my
> current oil cooler was good enough but marginal. On hot days I had to
> step climb. I don't have an exit scoop or air dam on the exit duct.
> The duct opening is flush with the fuselage. I'm really intrigued with
> Don's idea of an Oil cooler flap that can be adjusted from the
> cockpit. When flying with the IO360 I had too much cooling in the
> winter and marginal in the summer. I would tape some of the cooler
> face in the winter so my temps were hot enough to get a bit of warm
> air in the cabin. With a hinged controllable flap I could set it for
> whatever the conditions were. It would probably work out to 3 or 4
settings that covered all scenarios.
>
> Scott
>
>
>
>
>
> CyberDefender has scanned this email for potential threats.
> Version 2.0 / Build 4.03.29.01
> Get free PC security at www.cyberdefender.com
>
>
> ----------------------------------------------------------------------
> --
>
> ----------------------------------------------------------------------
> --
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery! www.tvbf.org/gallery user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail Check old archives:
> http://www.tvbf.org/archives/velocity/maillist.html
CyberDefender has scanned this email for potential threats.
Version 2.0 / Build 4.03.29.01
Get free PC security at www.cyberdefender.com
More information about the Reflector
mailing list