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Acclaim type s manifold pressure


Carwash guy

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I fly an acclaim type S, and have what appears to be an incorrect manifold pressure indication. I believe it to be about 5 inches or so off. For example, in order to get the correct fuel burn and knots for a 2400/ 21inch setting, I have to obtain a 2400/ 27 inch setting, at which point the fuel burn and TAS are almost dead on for 24 squared. Anyone else ever have this issue?

thanks

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Welcome aboard, CWG!

You are talking about the G1000 system, right?

if yes, do you know what the version of your software is?

you might search this site for the Manifold pressure sensor.  Use the search box at the top right of this page.

i recall somebody discussing the part and it's price a while ago...

just trying to help,

-a-

Edited by carusoam
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Welcome aboard, CWG!

You are talking about the G1000 system, right?

if yes, do you know what the version of your software is?

you might search this site for the Manifold pressure sensor.  Use the search box at the top right of this page.

i recall somebody discussing the part and it's price a while ago...

just trying to help,

-a-

thanks I will check it out

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Have you check the MP reading on the ground with engine off. Depending on the elevation the reading would be 30" minus one inch per 1,000 ft above msl.

José 

yes and it appears to be normal. As does the reading when I have it to the wall on climb. 33.5 give or take. I have found that with my TKS, I am very close to the regular acclaim on GPH and knots. For example, when flying LOP at 16,500, I was burning 15.6 GPH doing 195knots. I had to push MP up to 29.5 to achieve this, when book says a 24 MP is what you would expect to get that fuel flow.

 

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Really sounds like your MAP is properly indicating if its reading properly before start up and showing red-line at WOT on take off. But I can't seem to follow if you are saying you are not getting the desired fuel flow for 2400/21" best economy setting without pushing MAP in further? Which is very odd, since you should have to further lean mixture to bring it down to the best economy FF while also adjusting MAP to keep it at 21" .

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Additional data point from a well balanced NA IO550... That was limited to 2500rpm.  Are you not using 2550 rpm for cruise? (Based on Hartzell and sound)

At altitudes around 5k' it is possible to run close to 100°F LOP... Any more, the engine gets too quiet for my liking.

At altitudes around 12k' it is still possible to run close to 50°F LOP...

At the higher altitude the MP is descending toward around 20", and the AS is dropping off.   It is pretty efficient, yet terribly unfun in a slowish kind of way...

It is good to use excess air as an internal cylinder cooling mechanism.  But, the cost of that is too much speed lost.  Regaining the speed takes, bringing the mixture back towards about 10°F LOP. The differences (with the NA IO550) are 15gph to go 175Kts ROP vs. 12gph to go 165kts LOP... (Based on old memory?)

Of course you are going to see an immediate difference with the TN vs NA at altitude.  More MP available and less external air cooling. What CHTs are you seeing while running 65°F LOP.  Add the OAT for reference.

POH for the R:  Best Power is 65% @50ROP.  Best Economy is 55% @50LOP

best regards, -a-

 

Edited by carusoam
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