Hello Craig

I am surprised about your stats, as I recall fuel flow values between 19 and 22gph were the area’s where the engine gets really beaten up? I might be wrong, but on my last flight I tried just to see where it peaks (TIT) and was actually surprised that it peaked at a lower TIT than before.

In other words, if you use ‘your TIT temp’ as your gauge than this might be off as it does change with altitude and OAT.

Now I am still not very comfortable looking for peak (even going from the lean side) but it will get your surprised sometimes. I usually go smooth and fast (within 4 secs) and then I just know it was higher, but by how much I do not really know as I do not want to be in the red box too long.

Now in the past I was leaning on a much smaller power setting like 60%, and when I knew and was less than 80% LOP I just bumped the throttle back to 75%, but I am not even sure if this is the right or perhaps totally wrong way.

But some of the values in your chart looks like dangerous territory….I just hope I am wrong with my assumption.

So my questions:

Were you always leaning and if so did you do this at that power setting?

Did you lean on TIT or first/last cylinder? (depending from which side you lean)

From the lean side or rich side?

== Ronald (>400hours IVP, n45HL, the rest I do not count lol)

Hello Craig,

Thank you very much for your picture. I got a lot of information out of it and spent quite some time looking at it – you can feed me a lot more of these before I will get tired of it…

I kept a log of my power settings on different flights for the last year and I found one setting that is very similar to yours – unfortunately I didn’t get that good of a tailwind

My fuel flow shows a little less – may be this is a calibration problem? My TAS shows higher – but mine comes from the bezel and is influenced by friction heating and air compression – it would make me very happy if someone on the list could give me a correction factor for my speeds/conditions.

When I put my scribbled notes in a spread sheet and sorted it to altitude and OAT I found something in my opinion very interesting: on the lower altitudes the OAT has very little influence on the speed. At the higher altitudes (>=FL180) you can clearly see how the airspeed decreases with increasing OAT because I need to run the engine at lower power settings to get similar TIT and CHT.

On low altitudes (<FL120) it seems I can feed my engine a lot more fuel without significant influence on the CHT (may be because of my plenum) - The high power setting at FL110 was more than 1.5 years ago – I kept it in there for reference and I won’t do this again

On some warm/humid days I just have the feeling my engine doesn’t like it at altitudes higher than FL190. I don’t like higher than FL230 because I don’t have winglets and it doesn’t feel that firm anymore

Info for the chart: TIT is my TIT2 - it is usually 40F warmer, TIT max is around 1720, warmest CHT is always #2 and CHT#1 comes close after it, the TAS comes from the bezel and would need to be corrected, all settings were in cruise for at least 45 min or so – sometimes up to 2 to 3 hours.

Ralf

From: marv@lancair.net [mailto:marv@lancair.net]
Sent: Wednesday, October 16, 2013 3:47 PM
To: lml
Subject: Re: IV-P Recent Trip