The following messages are collected from the FSFAN international echo,
and are all about some of the new EGT, mixture, and prop control in FS5. 
I did not ask the authors for permission to upload this textfile, but I
assume that they cannot object because they are public messages. 
Some information is explained several times by different people, but I did
not want to change the messages.

This is intended solely for enhancing the fun of Flight Simulators by
broadening you knowledge about flying airplanes.

Enjoy, Eric Bakker.


 Area: FSFAN.FSF 
  Msg#: 2475                                         Date: 08-29-93  14:10
  From: Mathijs Kok                                  Read: Yes    Replied: No 
    To: All                                          Mark:                     
  Subj: New technology in fs5

When we start flying FS5 we will encounter a few new instruments and methods 
of control. I will start a short serie of articles which will describe these 
new items for you. Please understand I am no aircraft mechanic and I will 
have trouble translating some of the words. Please correct me if I make 
mistakes.
 
-!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!-
About the most important changes in the way we fly will be the introduction 
of a new propellor in FS5. In FS4 we were used to a 'fixed' prop and in Fs5 
we will be able to use a prop with variable pitch. Sounds not so important 
but just listen to this story.
When the Hurricane was introduced around 1935 it soon became the main fighter 
in the RAF, but from the beginning it lacked speed at high altitudes and 
climbing power. The plane was just not able to take on the new german 
fighters. That was until a new american variable pitch propeller was 
introduced. With this small change the plane was able to intercept and fight 
the german planes. It saved the day during the battle of Brittian (the 
Spitfire was important but lacking in numbers!) and is is well known this 
important battle would not have been won without the new prop. The 
manifactures of the prop told the world they saved the western world!
 
Now you know how important a good prop can be. But how can it make such a 
difference? Well, you all know a prop is like a screw. While it turns it 
'screws' itself into the air dragging the plane. But a screw does not know 
slip and when it is screwed into wood it will advance at a steady rate and 
can not be turned without moving backwards or forwards. A proppellor can, 
just step on the brakes and add power. The prop will spin faster but the 
plane will not move. This effect will always happen, at any speed. The prop 
will not screw into the air as much as is wanted.
 
An other thing to take into account is the speed at which the plane is 
travelling. The blades of the prop are not only turning but also moving 
forwards. And because a prop blade is a small wing it is like we want to 
create lift with a wing that is being dragged around with it's top forward. 
The designer has to make a prop that will works under these conditions.
The most important factor in this is the angle of the blades and the 
propellor shaft. It is like the grooves in the screw. If the grooves are 
close together, the screw will move only a little bit forwards with each 
revolution. If the grooves are not close the screw will move much faster but 
will be much harder to turn!
 
The proppelor works the same. If the plane is standing still or is travelling 
along the runway we want a prop that is designed for those speeds, it will 
have to deliver power without much airspeed. The angle of that prop will have 
to be small. It has to be 'in first gear'. If we are travelling at high speed 
conditions are very much changed. The prop that delivered such good 
performance at low speed is now almost useless. It will simply spin at high 
rpm and not give much power. For these condition we want a prop that bites 
into the air, has a much bigger angle to the air. With this prop we will need 
a giant runway to take-off but it will give high speed, great range and a 
high ceiling.
 
More in next message....
 
-!- FMail 0.94
 ! Origin: Stimulating Simulations with FsFan. (81:81/1.1)


 Area: FSFAN.FSF 
  Msg#: 2476                                         Date: 08-29-93  14:29
  From: Mathijs Kok                                  Read: Yes    Replied: No 
    To: All                                          Mark:                     
  Subj: New technology in fs5, pa

continued......
 
You can understand why the designers have always struggled with this problem. 
It is simply not possible to design a good propellor. It will always work 
best at a give speed and will always hinder the plane at other speeds.
 
This problem is even more important with high performance planes because the 
range of possible speeds is so great. Take the Cessna 182, it lands at 55 
knots, cruises at 140 knots and has a topspeed of 160 knots. The speed range 
will be 160-55= 105 knots. Now take an P51 Mustang. It lands at 80 knots, 
cruises at 250 knots and has been flown as fast as 450 knots. The speed range 
will be 450-80=370 knots!! Just think about a prop that has to cope with 
these conditions. The only way a proppellor plane can be flown in this speed 
range is with a variable pitch prop.
 
These propellors can change the angle of the blades. They can be changed 
during flight to make the best prop for any speed! This is done with 
oilpressure and these props are complex, expensive and heavy. Still they will 
add to the performance of any plane. In FS5 you will find a lever and in one 
of the dropdown menus a box called PROP ADVANCE with the settings FIXED PITCH 
/ MANUAL / AUTOMATIC. In real aviation a lot of planes have a automatic 
system. An other advantage of such a system is that if the engine is not 
running the propeller can be set in such a way that it has the smalles 
possible wind resistance. Dunno the right term in English but in Dutch this 
is called 'vaanstand'.
 
Hope this information will be helpfull. As said before, if you have more 
information, or the right english words please correct me.
 
Met vriendelijke groet, Mathijs Kok (namens FsFan)
 
-!- FMail 0.94
 ! Origin: Stimulating Simulations with FsFan. (81:81/1.1)


 Area: FSFAN.FSF 
  Msg#: 2477                                         Date: 08-29-93  14:32
  From: Mathijs Kok                                  Read: Yes    Replied: No 
    To: All                                          Mark:                     
  Subj: New technology in fs5, pa

Can anybody write something about a few new dials in FS5? For example what is:
 
-Manifold pressure.
-EGT.
-Mixture control.
 
Please help us all to understand more about the way we will fly FS5. If you 
have the knowledge please explain the way we will use this new intruments.
 
Met vriendelijke groet, Mathijs Kok (namens FsFan)
 
-!- FMail 0.94
 ! Origin: Stimulating Simulations with FsFan. (81:81/1.1)


 Area: FSFAN.FSF 
  Msg#: 197                                          Date: 08-30-93  12:00
  From: Dietmar Georges                              Read: Yes    Replied: No 
    To: All                                          Mark:                     
  Subj: New technology in fs5

 
MK>Can anybody write something about a few new dials in FS5? For example what
MK>is:
MK>
MK>-Manifold pressure.
MK>-EGT.
 
MK>-Mixture control.
    -!!!!!!!!!!!!!-
 
Hello All,
 
i never saw the new FS5 but it`s shurely true that we must use the new
instuments in a proper way like Mathijs wrote in some messages.
 
Something about the MIXTURE:
-!!!!!!!!!!!!!!!!!!!!!!!!!!-
The mixture lever is a simple and also valuable instrument to save fuel
and let run the engine for a long time.
The mixture lever is beside the power lever. If you push the lever
(standard take off setting) the mixture is rich. Much fuel and a few oxygen.
The engine will run safe now but it will use a lot of fuel.
During climb you can hold this setting. On cruise level you have to pull the
mixture lever for more effeciency. The mixture now goes to lean. Few fuel
and much oxygen.
And when you think the engine stops working when you pull the lever to much
you are right. It's just the way to stop the engine (but only at ground).
 
Reaching flight level you smoothly pull (or turn(you also can turn it))
the mixture - and be shure at some moment the engine will run a little bit
faster and then it stops. Just at this moment you have to push the lever
(but only a little bit).
Now you have the best mixture in your current flight level.
At every level change you have to repeat this procedure.
And remember, if you decent push the mixture lever, or it will happened
that the engine stops cause the mixture becomes lean at lower altitudes.
 
         .
Regards Dietmar
 
-!- CrossPoint v2.1 R
 ! Origin: I`m still searching (81:300/220.3)


 Area: FSFAN.FSF 
  Msg#: 1054                                         Date: 09-06-93  00:21
  From: Eric Bakker                                  Read: Yes    Replied: No 
    To: All                                          Mark:                     
  Subj: Fs5 new gages

Mathijs asked for some comments on the 'new' FS5 gages.
 
Manifold Pressure gage
======================
For airplanes with controllable pitch propellers this instrument is used
in combination with the tachometer to set up desired power from the
engine. The manifold pressure gage measures absolute pressure of the
fuel-air mixture going to the cylinders and indicates this in inches
mercury. When the engine is not running , the outside air pressure and
the pressure in the intake manifold are the same, so that the manifold
pressure gage will indicate the outside air pressure (as a barometer
would). This means 29.92 at sealevel, standard day.
Starting the engine and idling pressure drops to 10 inches. As you
open the throttle, you are allowing more and more fuel to enter the
engine, and manifold pressure increases accordingly. Maximum for
unsupercharged engines would be 28-29 Hg.
The above is taken from:
The instrument flight manual, by William K. Kershner (Iowa State
University Press).
 
*********************************************************************
This is what I found in the Information manual of the Cessna TR182 (the
turbo charged 182 RG):
This gage reads and indicates induction air manifold pressure in inches
of mercury (what's in a name...). 'Induction air' is the air after
entering the air filter, passing through the engine until it reaches the
combustion chamber. The 'induction manifold' (or 'intake manifold') is
the 'pipe' between the carburetor and the cylinders. The gage has a
normal operating range of 17 to 25 inches Hg, and maximum of 31 inches
Hg for the Cessna TR182.
 
Manifold Pressure variation with engine rpm
When RPM is increased, manifold pressure will increase. When RPM is
decreased, the manifold pressure will decrease.
 
Manifold Pressure variation with altitude
Manifold pressure will decrease with altitude unless throttle control
is advanced. Throttle control will be necessary to maintain the maximum
(31 Hg) or cruise (25) manifold pressure during climb.
 
Manifold Pressure variation with airspeed
When airspeed is increased, the manifold pressure is increased and
vice-versa.
 
Manifold Pressure variation with mixture
Enrichening the mixture will increase the manifold pressure, leaning
will decrease.
 
****************************************
I'm not a real pilot, so I apologize for any mistakes I made. All
comments are welcome.
 
Met vriendelijke groet, Eric Bakker


 Area: FSFAN.FSF 
  Msg#: 1055                                         Date: 09-06-93  00:55
  From: Eric Bakker                                  Read: Yes    Replied: No 
    To: All                                          Mark:                     
  Subj: New fs5 gages.

Hi All,
 
Mathijs asked us to supply more information on the new gages in FS5.
 
The EGT Gage (Exhaust Gas Temperature)
======================================
This instrument is designed to monitor engine performance and fuel-air
ratio (economy mixture). A probe in the exhaust collector assembly
measures exhaust gas temperature and transmits it to the indicator.
When the mixture is leaned from full rich, the exhaust temperature will
increase, peak, and then decrease with further leaning. The idea is to
get the mixture to the fuel-air ratio for continious operation and also
have an indication for best mixture for take-off and climb under
different situations, such as taking off at a high density altitude,
climb, etc.
 
The gage may be calibrated in 25 degr. Fahrenheit increment with no
figures shown (as in FS5) or in a range of 1200-1750 degr. F.
 
The Peak EGT is where the maximum utilization of the fuel and air
occurs; it's a chemical correct mixture. Peak EGT operations are
often limited to 75 percent rated power or below.
 
Best Economy mixture starts at the peak temperature. Expect a slight
loss of horsepower and 2-3 knots at cruise.
 
Best Power mixture is in the range of a temperature drop of 100-150
degrees Fahrenheit from the peak on the rich side.
 
A rule of thumb compromise between best economy and best power mixtures
has been a mixture setting of 50 degrees F. on the rich side of the
peak.
 
==================================================================
Above is derived from "the student pilot's Flight Manual" and the
"Instrument Flight Manual", both by William K. Kershner, Iowa State
University Press.
 
Met vriendelijke groet, Eric Bakker


 Area: FSFAN.FSF 
  Msg#: 262                                          Date: 08-31-93  17:54
  From: Mathijs Kok                                  Read: Yes    Replied: No 
    To: Fred Hoorn                                   Mark:                     
  Subj: New technology in fs5, pa

 > Hallo Mathijs,
 
 > 29 Aug 93, Mathijs Kok wrote to all:
 
 >  MK> These propellors can change the angle of the blades. They can be
 > changed
 >  MK> engine is not running the propeller can be set in such a way that it
 > has
 >  MK> the smalles possible wind resistance.
 
 > Thanks a lot for this good piece of information. Learned a lot that I
 > did not know. Do I understand this pitch issue, when I would say that
 > this prop is a turbo-fan of which the speed can de controlled as
 > well?
 
No, as far as I can see a turbo-fan is a jet engine wich turns a variable 
speed proppellor. Good for lower speeds, less noise and less fuel 
consumption. Short to medium range planes.
 
One thing I forgot to mention in my article. A plane with a variable speed 
prop can use it's engine with far greater effiency. Like the not variable 
speed prop has got a best speed, the airspeed at which the prop delivers the 
best performance, the enigine has got a best rpm also. In most engines this 
is at about 75 to 80% of max rpm. The plane with a variable speed prop can 
set it's props and leave the engine at the best operating rpm. If you 
increase fuel flow the enige will deliver more power but with the proppellor 
set a an higher angle the rpm will stay the same. Saves fuel and engine wear. 
This system is called 'constant speed'.
 
Met vriendelijke groet, Mathijs Kok (namens FsFan)
 
-!- FMail 0.94
 ! Origin: Stimulating Simulations with FsFan. (81:81/1.1)


 Area: FSFAN.FSF 
  Msg#: 263                                          Date: 09-02-93  20:37
  From: Ulrich Effertz                               Read: Yes    Replied: No 
    To: Mathijs Kok                                  Mark:                     
  Subj: New technology in fs5, pa

Hi Mathijs!
 
 MK> Can anybody write something about a few new dials in FS5? For example 
what
 MK> is:
 
 MK> -Manifold pressure.
 
Don't know exactly. Only, that it is used for the power setting.
 
 MK> -EGT.
 
EGT means Exhaust Gas Temperature and depends on the Mixture control.
If there's too much air or too much fuel in the mixture, the burning 
temperature goes down. The highest possible burning temperature is
called "peak EGT". It depends on outside temperature, power setting
and altitude.
 
The EGT is also important for the fuel consumption.
Even if a pilot would be able, with or without EGT measurement, to
lean the mixture for optimal power setting, it would be not profitable.
Optimal power setting is defined as the point, where a "real power"
in HP is produced by the lowest possible Manifold pressure.
Normally this point lies approximately 100 degrees Fahrenheit before
EGT in the direction of rich mixture. Tests showed, that the difference
in speed between "optimal power setting" and "peak EGT" is only 2 knots.
But the fuel consumption at "peak EGT" lies 15% below.
 
Normally EGT systems use display instruments with uncalibrated scales,
because the relative and not the absolute temperature is measured. The 
reference line in form of a needle or a symbol is adjusted depending on 
measurement results. Normally the scale has sections of 25 degrees
Fahrenheit. Every 100 degrees is marked by thicker lines.
 
 MK> -Mixture control.
 
Was descibed by Dietmar Georges on monday.
 
 MK> Please help us all to understand more about the way we will fly FS5. If
 MK> you have the knowledge please explain the way we will use this new
 MK> intruments.
 
I'm not a real world flyer, but have collected many articles from aviation 
magazines.
 
Tschoe
      Ulrich
 
-!- GoldED 2.41+
 ! Origin: Spread your wings and fly away (81:300/211.8)


 Area: FSFAN.FSF 
  Msg#: 337                                          Date: 09-01-93  21:49
  From: Marc Van De Voorde                           Read: Yes    Replied: No 
    To: Mathijs Kok                                  Mark:                     
  Subj: New technology in fs5, pa

Hy Mathijs,
 
* In a message on to all (') , Mathijs Kok said:
 MK > Can anybody write something about a few new dials in FS5?
 MK > For example what is:
 MK > -Mixture control.
 
I was (once) a fanatic radocontroled chopper pilot and "mixture control" was 
an absolutely important factor: it al depends on altitude and 
weather-environment.
If it's cold (or: of course: if your altitude is high), your fuel-mixture has
to be set as "rich" : more fuel and oil is pumped into the cilinders. Danger:
if your mixture is too rich, the engine wil drown in his own fuel.....
 
If it's hot (or also: if your altitude is low), the mixture should be set 
'poor':  the engine will produce more rpm's (and horsepower)=> better 
combustion. Danger: the engine will stall (no fuel) if your mixture is set to
low.
I hope this is an answer to (1) of your questions?
Greetz Nostromo (Flight sim club Flanders)
 
-!- FMail 0.92
 ! Origin: Quantum Leap Stargate > (81:200/102)


 Area: FSFAN.FSF 
  Msg#: 339                                          Date: 09-02-93  21:16
  From: Luc Henderieckx                              Read: Yes    Replied: No 
    To: Mathijs Kok                                  Mark:                     
  Subj: New technology in fs5, pa

Mathijs,
 
In a msg of <Sunday August 29 1993>, Mathijs Kok writes to all:
 
 MK> Can anybody write something about a few new dials in FS5? For example
 MK> what is:
 
 MK> -Manifold pressure.
 
This is effectively the absolute pressure inside the tubes who deliver the 
air/fuel mixture (or air alone in fuel injection systems before the fuel 
nozzles) to the cylinders. It is a measure of the power developped by the 
engine (the higher this pressure, the higher the power output). It is also a 
very important indication of the relative charge of the engine, which gives 
also an indication of fuel flow (=fuel consumption) and combustion 
temperature (risk of detonation).
 
 MK> -EGT.
 
I'll have to look up this one !
 
 MK> -Mixture control.
 
A control to manually change the the ratio of fuel to air. Normally a mixture 
of 1 part gasoil to 14 parts air (in weight) will burn 100 % (no more fuel or 
oxygen in the exhaust). As you propably know the air pressure changes as a 
function of the altitude (lower pressure on higher altitudes), which means 
that less oxygen is available at higher altitude. Since the flow of fuel 
injected in the carburettor is only function of the speed of the air inside 
the venturi of the carburettor your mixture is becomming too rich at higher 
altitudes. This causes the engine power to drop, and some unburnt fuel will 
leave the engine via the exhaust (which is a waste and pollutes the air).
 
B.T.W. in so called atmospheric engines (without turbo-charger) the maximum 
power is determined by the atmospheric pressure at the intake of the engine. 
This is so because you can only burn so much fuel as there is oxygen 
available to burn it. At lower pressure less oxygen is sucked in the 
combustion chamber limiting the quantity of fuel you can burn per revolution 
and hence limiting the produced energy per revolution of the engine.
 
Kind Regards,
 
Luc
 
-!- GoldED 2.41+
 ! Origin:  --> OO-778 Ultralight Deltaplane <--  (81:200/1)


 Area: FSFAN.FSF 
  Msg#: 846                                          Date: 09-05-93  12:00
  From: Dietmar Georges                              Read: Yes    Replied: No 
    To: Mathijs Kok                                  Mark:                     
  Subj: New technology in fs5

Mathijs Kok@81:81/1.1 wrote on 03.09.93
 
MK> > During climb you can hold this setting. On cruise level you have to
MK> > pull the
MK> > mixture lever for more effeciency. The mixture now goes to lean. Few
MK> > fuel
MK> > and much oxygen.
MK>
MK>Will it also run hotter and deliver more power at this setting?
 
Yes. An additional effect of the mixture is that it can "cool" the
engine. If you lean the the mixture to much it`s possible that there
is not enough fuel to cool the engine and it may run hot.
So it`s also better you don`t lean the plane at power climb.
 
Some rules for the mixture and EGT:
 
- relation Fuel/oxygen; from 1:10 (rich) to 1:17 (lean)
- relation > 1:17 (to lean) => power descents; engine runs hot
- relation < 1:10 (to rich) => power descents; you need much fuel
- relation 1:15 = CCM (chemical correct mixture) means, that
  you have the highest EGT ( ca. 900 C)
  You can adjust it exatly only with the EGT insrument (peak EGT)
- relation 1:12,5 is the setting you can adjust with the procedure
  i explaned the message before when there's no EGT avaliable.
 
  1:12,5 is a good choice for the smaller aircrafts.
 
I think you have flown the fs5 for some hours. Is it really possible
to use all these complex functions ? It would be great ! :-)
 
         .
Regards Dietmar
  
-!- CrossPoint v2.1 R
 ! Origin: I`m still searching (81:300/220.3)
