lml@lancaironline.net Mailing List Archive

Hi Jack

The statement was just on the graphic, nothing more. And when I saw this my neck hair was standing up lol

And yes those numbers sounds correct to me, not to lean less than 150 degrees ROP > 65% power. But I did see some numbers recently passing by that are (in my humble opinion) very close to the danger zone, that is why I was just mentioning this.

Thanks again -- Ronald

On Jan 8, 2012, at 8:50 PM, J H Webb wrote:

Hello Ronald,

I am at a loss figuring out what you are saying in sentence one. Oh I found what you are referring to. Those numbers are just indications of that fuel flow at that power but (the big but) if you read the TCM manual carefully you will note that TCM does not recommend leaning below 150 deg rich of peak above 65% power. The manual recommends any mixture strength at and below 65% power. That number on the 75% number is just for reference not a recommendation for normal operation.

Jack Webb
LIV L360
Former Chief engineering Test Pilot
BSAE

From: Ronald STEVENS <Ronald@sdc.com>
To: lml@lancaironline.net
Sent: Friday, January 6, 2012 1:09 PM
Subject: [LML] Re: Lancair 4P power settings

Hello Jack

I do not want to sound like an.......ass lol But on those chart you have a statement that contradict with most 'experts' saying that 50% Rich at 75% is precisely the wrong spot to be !!

So I would be careful using this chart running your engine. This might be the 'old' chart they used to have before Gammi and the rest came up with better numbers. For example at 50% you can set the mixture anywhere without harming your engine etc etc....

I guess TCM just wants to sell lots of cylinders LOL

== Ronald (>130h lancair 4p, 1400h in others)

On Jan 6, 2012, at 7:44 AM, J H Webb wrote:

Here is a power chart for the TSIO550 from TCM that I added red lines and cleaned up a little as it did not scan well.

Jack Webb
L360 LIV
Years as engineering test pilot

From: Jay Phillips <jayph@fastairplane.net>
To: lml@lancaironline.net
Sent: Thursday, January 5, 2012 4:58 PM
Subject: [LML] Re: Lancair 4P power settings

A first order approximation is to consider a linear relation exists between
MP, RPM, and power.

TCM says that 38.5" MP and 2700 RPM gives 100% power (350 hp)

Cruise setting of 31" MP and 2500 RPM thus gives (31/38.5) * (2500/2700) =
74.5% or 261 hp

Another example: 28" MP and 2400 RPM: (28/38.5) * (2400/2700) = 64.6% or 226
hp

So you can calculate the power with different settings, or choose you power
and back-calculate to determine the settings requried.

Jay Phillips
Legacy N92SX
IV-P N516DB

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Tony
Ketelaars
Sent: Thursday, January 05, 2012 12:00 PM
To: lml@lancaironline.net
Subject: [LML] Lancair 4P power settings

Can any one tell me what the MAP/RPM power settings are for the
Lanceair 4P TSIO550
Like 60 - 65 - 70 - 75%

Thanks

Tony Ketelaars

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