That looks really good. The only caveat I would see is that you might need to run the test multiple times to know its repeatable and predictable.

John Barrett

Sent from my iPad


> On Aug 10, 2014, at 1:57 PM, "Jay Phillips" <jayph@fastairplane.net> wrote:
>
> I'm going to have to take back what I said about climb speeds, at least
> conditionally.
>
> For comparison, the general take-off and climb profile I use is as follows:
>
> Take-off: 2700 RPM, full-rich mixture, WOT, yields 38.5" MP, and about 42
> gph fuel flow. I stay with this until I reach 1500' AGL, then reduce RPM to
> 2500 and Throttle to 31.5" MAP. I then climb using these settings and 165
> IAS until I reach cruise altitude. I struggle to keep the hottest cylinders
> (#3 & #4) below 400F. Total flight time from lift-off to 17,500' MSL
> (starting at 5,100' AGL field elevation) is typically 20-22 minutes at an
> average burn rate of about 25 gph.
>
> This morning I performed a test: at 1500' AGL I reduced RPM to 2500, but
> left WOT and full-rich mixture. I set the AP for 145 IAS climb to 17,500 MSL
> (starting at 5100' field elevation). Total flight time was 11:05.  Fuel burn
> average was around 35 gph. The best part? Hottest cylinder (#3) never went
> over 380F.
>
> 25 gph for 20 minutes = 8.3 gallons.
> 35 gph for 11 minutes = 6.4 gallons.
>
> So the WOT climb profile is faster, burns less fuel, and keeps the cylinders
> cooler. Anyone see anything wrong with this?
>
> Jay Phillips
>
> -----Original Message-----
> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Jay
> Phillips
> Sent: Thursday, August 07, 2014 4:28 AM
> To: Lancair Mailing List
> Subject: [LML] Re: High CHTs on #2, TSIO 550
>
> Thomas,
>
> I had a similar problem when I first bought my IV-P - #2 ran hot during
> climb, and I could alleviate it a bit by partially closing the oil cooler
> door.
>
> The back side of the #2 cylinder is right up against the forward side of the
> oil cooler. It doesn't leave much room for airflow. I had a modification
> installed (don't know what it is called, but any shop knowledgeable on
> IV-P's should know what it is) that added some concavity to the front side
> of the oil cooler, providing more room for airflow around the back of the #2
> cylinder.
>
> In my case, at the same time we discovered I had a burned exhaust valve on
> the #2 cylinder. Whether that was related or not I'll leave to the engine
> experts. We also changed the baffling around the prop hub to better control
> the airflow. After all was said and done (including an engine overhaul -
> different problem) my #2 CHT now behaves and #'s 1,2, 5, and 6 are pretty
> close in CHT. #'s 3 and 4 are now my warmest. I still don't have it where I
> want it but it is a lot better.
>
> I think your IAS during climb is too low. Try using 165 or 175 IAS for climb
> speed and see how that affects things. Using 165 I used to have to level off
> at about 13,000' to allow the airspeed to climb and provide cooling air and
> time to bring my CHT back down. Once it was trending downwards I would
> continue the climb.
>
> You don't mention your MP during climb. I used to (and still do sometimes)
> used 31.5" during climb. One suggestion I received was to continue climbing
> at WOT. That helped a lot although it uses a lot of fuel. I've also tried
> lowering power to somewhere between 27.5" - 29.5" - that also helps.
>
> If you haven't already you should check compression and put a borescope into
> #2 to make sure something else isn't going on.
>
> Jay Phillips
>
> -----Original Message-----
> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
> Thomas Whalen
> Sent: Wednesday, August 06, 2014 1:20 PM
> To: Lancair Mailing List
> Subject: [LML] High CHTs on #2, TSIO 550
>
> I have been fighting for over a year to try to keep the #2 CHT below 400 dg
> on the climb. It has hit as high as 430. I leave it full rich and climb at
> 140kts. When I level off, I then LOP and then #1 cools off. I have the
> Lancair baffles and RTV the gaps with the engine and have a good baffle
> seal. I even covered my 3rd intercooler and that only helped a little.
> Behind the prop the baffle seals up to the top cowl but not down to the
> bottom. I have seen it the reverse of that as well. If close the oil cooler
> door the CHT will drop 5dg at times.
> This was a factory new engine.
> Any suggestions?
>
> Thomas Whalen
> N444TW
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