the old saw is "it's not how hard you run it. it's how you run it hard."

The thing you are trying to avoid is high internal peak pressure.

That is more about mixture and spark timing than MAP.

I would not hesitate to run 32 inches IF I knew I was well lean of peak AND both TIT's were below 1650 AND all CHT's below 380.

If you have a 7.5:1 compression engine, that should give you a fuel flow of 17.6 gph or so, depending on

which limit you hit first.

If you haven't read this series it's well worth it.  See articles 63,64, 65, 66

http://www.avweb.com/news/pelican/182146-1.html

...and then take the APS course.  worth every penny.  there's a cheaper online-only one if you don't really want to see the computerized test cell in action and a lot of good live interaction.

http://www.advancedpilot.com/  

On Aug 14, 2011, at 9:27 AM, <bronnenmeier@GROBSYSTEMS.COM> <bronnenmeier@GROBSYSTEMS.COM> wrote:

Hello Craig,

 

Do you have the GAMI injectors or was your engine set up in a special way?

I thought that LOP operations are approved up to 28 inHG. I would like to run mine with 32 inHg but I am afraid to damage something.

Here is what I see so far:

Climb – full power – full rich (this gives me the coolest temps) – 160…170 IAS – CHT 380 – 390 – results in 1600 ft/min (beginning) 800 ft/min (end)

Level off at FL22, FL23 – full power – full rich – TAS 292…297 (on the bezel – I know this reads high) – #3+4 CHT 380 - 390

After this LOP at FL22, FL23 at 28 inHG, 16.1 gph – TAS 270…275 (on the bezel) – #1 CHT 360…375

Like I said I would like to run it at 32 inHg LOP but I am afraid I damage something.

 

Ralf

 

From: Craig Berland. [mailto:cberland@systems3.net] 
Sent: Friday, August 12, 2011 2:48 PM
To: lml@lancaironline.net
Subject: [LML] What are your numbers??

 

Going to Oshkosh:

25,000 ft

ISA +36 degF

2500 RPM

32 inHg

16.9 gph LOP

276 kts TAS (Chelton)

374 degF, #2 CHT

5.1 psi cabin pressure

In my limited IV-P time, I see about 3 kts per 1000 ft altitude increase. CHT’s at 18,000 ft are very low (345 degF) and CHT’s at 25,000 ft are as above when LOP.  I don’t fly ROP except for climb.  OAT significantly affects fuel flow and therefore speed when LOP.  The IV-P is a fantastic traveling machine.

 

Craig Berland

N7VG

 

 

Hello guys

So today I was happy flying with my 4p going from Daytona to Raleigh and was wondering what cruise numbers you are using.

For example I was cruising with a MAP of 29, FF=16.7, 2500rpm and did 234kts at 17500ft.

The plane seemed to be very happy, temps were perfect, engine sounded happy.

So what are your numbers? LOP? ROP? Ron Stevens