A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Piloting
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

From Piper Chieftan manual regarding engines



 
 
Thread Tools Display Modes
  #1  
Old December 2nd 05, 01:46 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

Come across another thing that has puzzled me (big surprise).

Here's a transcript from the manual:

"Under full throttle operations (such as takeoff and climb) the engines of
the aircraft have been adjusted to provide 43 inches of manifold pressure at
seal level and standard temperature. It is possible to read higher (up to 49
inches of manifold pressure) or lower than 43 inches of hg. manifold
pressure when ambient temperatures are higher or lower, respectively, than
standard."

I tried to explain to myself why the MAP would go up with higher than
standard temp, and down with the opposite situation. I came up a blank.

So, I'm asking the group. Why does this happen?

TIA.


  #2  
Old December 2nd 05, 02:31 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

Primarily because the absolute pressure controller senses the
temperature of the induction air between the turbo compressor outlet
and the fuel servo and adjusts the "absolute" maximum MAP according to
temperature by controlling exhaust wastegate position.

When setting up this controller, a temp probe is inserted into the
induction airstream and the temperature at max power measured. Using a
Lycoming chart, the max MAP is adjusted according to the indicated
temperature.

MAP/RPM is a relatively crude way of indicating horsepower. In simplest
terms, when the induction temp goes up, horsepower goes
down-consequently when induction temp goes down, horsepower goes up.
The absolute controller, in theory, maintains this temp change/HP
curve. But an initial start/rig point must be established after engine
installation or absolute controller change.

TC

  #3  
Old December 3rd 05, 11:43 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

Thanks for that.

I was having a hard time understanding what was going on. All makes sense
now.


  #4  
Old December 4th 05, 12:24 AM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

On Sat, 03 Dec 2005 22:43:28 GMT, "xerj" wrote:

Thanks for that.

I was having a hard time understanding what was going on. All makes sense
now.

Good deal.

You flying one? getting ready to fly one?

I allegedly useta fix them, and still have details of most of the
systems rattling around in my skull.

TC
  #5  
Old December 4th 05, 02:24 AM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

Unfortunately not at the moment. I have flown one, though. A rickety old
thing used mainly for type endorsements.

I'm preparing to get back into flying after a looooooong hiatus, if I can
find the spare money.Could still be some months away at the earliest. I'm
doing a lot of reading and learning about things I really didn't understand
previously, but just did because that was the way I was taught.

I find it useful to go through POHs and look at the procedures and the
performance charts and explain to myself why things are done the way they
are, and why the charts come out the way they do. I found the Chieftan one
the other day, and it's a good, complex plane to try to come to theoretical
grips with.

wrote in message
...
On Sat, 03 Dec 2005 22:43:28 GMT, "xerj" wrote:

Thanks for that.

I was having a hard time understanding what was going on. All makes sense
now.

Good deal.

You flying one? getting ready to fly one?

I allegedly useta fix them, and still have details of most of the
systems rattling around in my skull.

TC



  #6  
Old December 2nd 05, 03:28 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

It is possible to read higher (up to 49 inches of manifold pressure

And the MP gauge is redlined at 40" IIRC - at least the one in my
pals's Panther Navajo is.

Toecutter's post was correct in that the pressure controller must be
set to allow the engine to make its full rated HP allowing for a range
of OATs.

  #7  
Old December 2nd 05, 09:39 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

wrote in message
And the MP gauge is redlined at 40" IIRC - at least the one in my
pals's Panther Navajo is.


The Chieftain has a higher horsepower rating (350 hp) with a higher MAP
redline (49").

D.


  #8  
Old December 2nd 05, 10:22 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

The Panther Navajo has the 350hp Chieftain engines. IIRC my friend told
me the MP redline is still 40" although on takeoff he normally sees
42-43"

  #9  
Old December 2nd 05, 10:41 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: n/a
Default From Piper Chieftan manual regarding engines

Colemill has always been good at grey area performance changes.
Typically, when converting to a higher HP engine, they de-rate the
install by reduced "redlines" in theory reflecting what is comparable
to the original install max TO HP. Then they put in a neat little
statement something along the lines of the aircraft will meet or exceed
the original performance numbers.

TC

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Book Review: Converting Auto Engines for Experimental Aircraft , Finch Paul Home Built 0 October 18th 04 10:14 PM
P-3C Ditches with Four Engines Out, All Survive! Scet Military Aviation 6 September 27th 04 01:09 AM
PBJ-1(Navy mitchell) manual and bunch of ac. manuals FS Nenad Miklusev Naval Aviation 0 April 23rd 04 09:08 PM
Polikarpov PO-2 manual FS,books & Resin kits FS Nenad Miklusev General Aviation 0 April 23rd 04 09:07 PM
FS: Piper Navajo Chieftain 350 Manual Mike Aviation Marketplace 0 August 7th 03 12:15 AM


All times are GMT +1. The time now is 02:12 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AviationBanter.
The comments are property of their posters.