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XyZspineZyX
06-23-2003, 01:13 AM
I've been very intrigued by the engine management features of FB. Unfortunately, FB does not have the greatest manual in the world IMO so I set out to obtain info on these new features by doing searches on the forum and reading up on a few sites.

The following is a description of the conclusions I have arrived at in explanation of the new features. Please, correct me if any of these are wrong and feel free to add your own comments. Hopefully, this thread will verify my conclusion as well as serve as a reference to new players that have questions of these features.

Propeller pitch:
-Somewhat similar to car gears
-High settings are used for climbing and faster speeds but put more stress on the engine.
-Low settings are used for diving and cruising. Specially useful for dives since the engine RPMs might increase too much on a dive.

Mixtures
-Controls the mixture of fuel and oxygen and must be regulated for the engine to have an optimal burn-rate.
-High settings are used on low altitudes and on some planes that require it for WEP.
-Low settings are used at high altitudes since the air is much thinner. Less oxygen means more air has to be taken in by the engine.

*It has been stated that there is a bug with mixtures and that the numbers are actually reversed. Is that true?

Magnetos
-Provide the startup juice on the engines.
-They only have to be tested once before lift-off to see if they are working properly. A decrease in RPMs when shutting off the magnetos means that they are working properly.
-Other than the above reasons, there is no need to play around with them.

Superchargers
-Help the plane fly faster at higher altitudes by compressing air (dunno where, how, or why)
-Set the supercharger to stage one at low altitudes
-Set supercharger to stage two on high altitudes
-The altitudes depend on the plane you are flying
-Setting supercharger to stage two on low altitudes overstresses the engine and could lead to overheating or malfunction.

Radiator
-Opening the radiator cools it down but creates drag
-Closes it does the opposite
-Recommended: Leave radiator closed in combat, if overheating occurs, leave the scene of battle and open radiator.

*I'm not quite sure about the positions. Do higher positions mean that the radiator is more "open"?


And here's a little question on my behalf, albeit it is a stupid one:

What are drop tanks? Some planes can drop them but they don't go boom! Why and when should I use them. Why do they require their own button (jettison drop tanks) and are they ment to just be dropped or must something else be done with/to them?

XyZspineZyX
06-23-2003, 01:13 AM
I've been very intrigued by the engine management features of FB. Unfortunately, FB does not have the greatest manual in the world IMO so I set out to obtain info on these new features by doing searches on the forum and reading up on a few sites.

The following is a description of the conclusions I have arrived at in explanation of the new features. Please, correct me if any of these are wrong and feel free to add your own comments. Hopefully, this thread will verify my conclusion as well as serve as a reference to new players that have questions of these features.

Propeller pitch:
-Somewhat similar to car gears
-High settings are used for climbing and faster speeds but put more stress on the engine.
-Low settings are used for diving and cruising. Specially useful for dives since the engine RPMs might increase too much on a dive.

Mixtures
-Controls the mixture of fuel and oxygen and must be regulated for the engine to have an optimal burn-rate.
-High settings are used on low altitudes and on some planes that require it for WEP.
-Low settings are used at high altitudes since the air is much thinner. Less oxygen means more air has to be taken in by the engine.

*It has been stated that there is a bug with mixtures and that the numbers are actually reversed. Is that true?

Magnetos
-Provide the startup juice on the engines.
-They only have to be tested once before lift-off to see if they are working properly. A decrease in RPMs when shutting off the magnetos means that they are working properly.
-Other than the above reasons, there is no need to play around with them.

Superchargers
-Help the plane fly faster at higher altitudes by compressing air (dunno where, how, or why)
-Set the supercharger to stage one at low altitudes
-Set supercharger to stage two on high altitudes
-The altitudes depend on the plane you are flying
-Setting supercharger to stage two on low altitudes overstresses the engine and could lead to overheating or malfunction.

Radiator
-Opening the radiator cools it down but creates drag
-Closes it does the opposite
-Recommended: Leave radiator closed in combat, if overheating occurs, leave the scene of battle and open radiator.

*I'm not quite sure about the positions. Do higher positions mean that the radiator is more "open"?


And here's a little question on my behalf, albeit it is a stupid one:

What are drop tanks? Some planes can drop them but they don't go boom! Why and when should I use them. Why do they require their own button (jettison drop tanks) and are they ment to just be dropped or must something else be done with/to them?

XyZspineZyX
06-23-2003, 01:36 AM
about the drop tanks: the drop tanks are simply tanks of gasoline that the plane carry when making long missions. You usually drop the tanks when the gasoline is used up or when enganing in combat(the additional drag of the gas tank is quite uncomfortable)

XyZspineZyX
06-23-2003, 01:42 AM
Your other thread says your flying the La5FN. If that's the case. Ithas a constant speed prop, and doesn't really require ant setting change unless your going for economy. Just leave it on 100% for best performance. This may change in the patch.

The mixtures are correct. It's the pitch that is reversed.

I would never leave a fight because of overheating. You can just open rad as soon as it overheats, and keep fighting. Having the rad open duringa fight doesn't hurt you that much as the speeds ar lower. It's only when your trying to get top speed that it hurts you.

The drop tanks are for extra fuel. youdrop them when theu're empty.

Da Buzz
---------------------------------------------------------------------------------------
Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be.... Adolf Galland
<center>
http://www.elknet.pl/acestory/foto/rall4.jpg

XyZspineZyX
06-23-2003, 01:45 AM
Drop tanks are used to increase an airplane's range. They are 'drop tanks' because they can be dropped in an engagement- their extra weight reduced your aircraft's performance. USAAF drop tanks were, strangely enough, made of a pressed paper painted with an aluminum paint. A glass elbow conected them to the fuel system in the wings. the reason they don't explode is that a seperate detonator had to be installed. gasoline and Avgas are volatile, but dropping a platic gallon container of gas doesn't make it explode.

As soon as you're in combat, release your drop tanks. The extra fuel does you no good if you're dead.

They were introduced because to make room for another 200 or so gallons of gas in a fighter would not only hamper it's performance until that gas was burned, but it would make the plane physically larger, further hurting performance and also making it a bigger target. The solution was the drop tank, it's a compromise.

A supercharger is a mechanical device usually installed on the intake manifold of an internal combustion engine. It is driven by the engine, to pack more air into the 'plenum' which can be a simple box under the fuel management system, either a carburetor or fuel injection setup, the intake manifold, and ultimately the combustion chambers. Since an internal combustion engine is essentially a big air pump, the more air you put into it and get out of it, the better. On a car, the typical "mailbox" or "bug catcher" air scoop assoiated with a supercharger commonly covers the carbs. Underneath is a plenum chamber, and a set of impellers, much like two large screws that rotate into each other. Sometimes this plenum takes the place of the intake manifold in function. This is the mechanical means (in a very basic sense) by which the supercharger does it's thing. High internal stresses are a common result of supercharging.

A turbo charger uses exhaust gasses to spin a turbine which does the same thing, but it can take a while to 'spool up'. A small turbo spools quicker but isn't as powerful. A larger turbo spools slower but makes more power, in general. Today, there are varibale pitch turbos that decrease 'turbo' lag with larger turbos.



Message Edited on 06/23/0301:47AM by BBB462cid

XyZspineZyX
06-23-2003, 01:49 AM
Thanks for the info on engine management but i have one question.

Isnt engine mixture used to regulate fuel to the engine. i thought you would only use it to conserve fuel, does it have any effect on preformance other than the above mentioned?

to see sig. click link
http://hostmysig.com/data/bf109/5452.php
because ubi doesn't support php

XyZspineZyX
06-23-2003, 01:49 AM
there are some readme type files kicking around on the FB install CD's somewhere that have more info than the manual on the CEM issue.

XyZspineZyX
06-23-2003, 01:53 AM
partyanima

It does regulate fuel. At high altitude you have less air, and have to feed in less fuel, to keep the right ratio of fuel/air.

Da Buzz
---------------------------------------------------------------------------------------
Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be.... Adolf Galland
<center>
http://www.elknet.pl/acestory/foto/rall4.jpg

XyZspineZyX
06-23-2003, 02:01 AM
To quantify radiator drag:

In the 109K4, opening the radiator fully causes a 50km/h reduction in top speed.

The amount of speed loss increases exponentially as your airspeed increases. At climbing speed, the difference between open and closed is negligble.

XyZspineZyX
06-23-2003, 02:11 AM
partyanima wrote:
- Thanks for the info on engine management but i have
- one question.
-
- Isnt engine mixture used to regulate fuel to the
- engine. i thought you would only use it to conserve
- fuel, does it have any effect on preformance other
- than the above mentioned?
-


You will get a dropin engine revs at altitude unles syou drop the mixture back.

As an example a Yak 9 at 4000 metres will drop off 400 rpm at 100% mixture compared to 80%. By 5500 metres you need to go as low as 60% mixture to get full revs.


Also with regard to radiator.

On some planes (e.g. Lagg 3) the radiator really effects low speed handling badly. In addition closing the radiator makes the engine less vulnerable to damage from enemy fire and flak.

XyZspineZyX
06-23-2003, 02:29 AM
Axyun wrote:
- Propeller pitch:
--Somewhat similar to car gears
--High settings are used for climbing and faster speeds but put more stress on the engine.
--Low settings are used for diving and cruising. Specially useful for dives since the engine RPMs might increase too much on a dive.

A better analogy for prop pitch: fan blades. Take two fans with equal diameter blades, but one with deeper angles. If you spin both at the same speed, the one with the deeper angle moves more air, but requires mor energy to spin. In other words: if both fans use electric motors, the lesser-angled fan could spin 1,000 rpm on a 1/4 hp motor, while the high-angled fan would need a 3/4 hp motor to reach 1,000 rpm because its fanblades bite more air and therefore need more torque in order to spin. Prop pitch is just a way of moving the angle of the blade, which reqiures more torque to work, but moves more air.

Engines develope more torque/ hp at higher rpms, by the way.

- Mixtures
--Controls the mixture of fuel and oxygen and must be regulated for the engine to have an optimal burn-rate.
--High settings are used on low altitudes and on some planes that require it for WEP.
--Low settings are used at high altitudes since the air is much thinner. Less oxygen means more air has to be taken in by the engine.

You've got mixture down. If air-temp is modelled in the game, winter maps should allow richer fuel mixtures, therefore more power.

- *It has been stated that there is a bug with
- mixtures and that the numbers are actually reversed.
- Is that true?
-
-
- Magnetos
--Provide the startup juice on the engines.
--They only have to be tested once before lift-off to see if they are working properly. A decrease in RPMs when shutting off the magnetos means that they are working properly.
--Other than the above reasons, there is no need to play around with them.

Correct: leave these alone. /i/smilies/16x16_smiley-happy.gif

- Superchargers
--Help the plane fly faster at higher altitudes by compressing air (dunno where, how, or why)
--Set the supercharger to stage one at low altitudes
--Set supercharger to stage two on high altitudes
--The altitudes depend on the plane you are flying
--Setting supercharger to stage two on low altitudes overstresses the engine and could lead to overheating or malfunction.

Superchargers are belt/gear-driven fans that cram more air into the engine. The can allow you to run richer mixture in air-densities that normally would not allow for it.

- Radiator
--Opening the radiator cools it down but creates drag
--Closes it does the opposite
--Recommended: Leave radiator closed in combat, if overheating occurs, leave the scene of battle and open radiator.
-
- *I'm not quite sure about the positions. Do higher
- positions mean that the radiator is more "open"?

Correct on all acounts.

- And here's a little question on my behalf, albeit it
- is a stupid one:
-
- What are drop tanks? Some planes can drop them but
- they don't go boom! Why and when should I use them.
- Why do they require their own button (jettison drop
- tanks) and are they ment to just be dropped or must
- something else be done with/to them?

Extra fuel for long trips. Drop them when empty, or in some planes, when you need an extra bomb /i/smilies/16x16_smiley-wink.gif

<font face="Courier New">
&nbspBaldieJr
_____ | _____
_\__(o)__/_
./ \.
Whiners don't play vulchers
(er, winners)
</font>

XyZspineZyX
06-23-2003, 02:35 AM
BaldieJr

How can you say leaving a fight because you overheat is correct? Did you read anybody elses posts?

Da Buzz
---------------------------------------------------------------------------------------
Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be.... Adolf Galland
<center>
http://www.elknet.pl/acestory/foto/rall4.jpg

XyZspineZyX
06-23-2003, 02:40 AM
BuzzU wrote:
- BaldieJr
-
- How can you say leaving a fight because you
- overheat is correct? Did you read anybody elses
- posts?
-
-
- Da Buzz

No, I didn't. Thanks for asking.

<font face="Courier New">
&nbspBaldieJr
_____ | _____
_\__(o)__/_
./ \.
Whiners don't play vulchers
(er, winners)
</font>

XyZspineZyX
06-23-2003, 02:49 AM
How about answering both questions?

Da Buzz
---------------------------------------------------------------------------------------
Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be.... Adolf Galland
<center>
http://www.elknet.pl/acestory/foto/rall4.jpg

XyZspineZyX
06-23-2003, 03:36 AM
Thanks for the advice and confirmations.

It seems to me like there are different views on how to handle the radiator and what to do when overheating.

I guess that would depend more on the plane and situation.

If the plane can cool down fast and the drag caused by an open radiator is negligible then I guess it wouldn't be necessary to leave combat.

But if the opposite holds true and you are pretty sure your buds can clean up the remaining enemies then I guess it would be wiser to leave combat.

On the other hand, if your help is really needed, overheating or not, you should do your best to stay in the fight.

XyZspineZyX
06-23-2003, 03:47 AM
When you first get the overheat message. Do something right then to correct it. The longer youwait, the longer it takes to cool off. All planes are different, and need a different kind of attention. You are flying the La5FN. This is the best plane for not overheating. Just pulling back the throttle a little will usually cool it off.Even with a closed radiator. It will also let you run a long time overheating without engine damage. I don't recommend that though. Open the radiator, or reduce throttle, or a little of both. I hate seeing the overheat warning on, so I usually fix it right away.

Da Buzz
---------------------------------------------------------------------------------------
Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be.... Adolf Galland
<center>
http://www.elknet.pl/acestory/foto/rall4.jpg

XyZspineZyX
06-23-2003, 03:51 AM
It's not a huge feature, more cosmetic, but I'd like to be able to open my canopy. That would be sweet http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

XyZspineZyX
06-23-2003, 03:55 AM
http://mywebpages.comcast.net/Tailspin/index.htm
Cruise this site...lots of what you need to know.



<CENTER>http://www.world-wide-net.com/tuskegeeairmen/ta-1943.jpg <marquee><FONT COLOR="RED"><FONT SIZE="+1">"Straighten up.......Fly right..~S~"<FONT SIZE> </marquee> http://www.geocities.com/rt_bearcat

<CENTER><FONT COLOR="ORANGE">vflyer@comcast.net<FONT COLOR>
<Center><div style="width:200;color:red;font-size:18pt;filter:shadow Blur[color=red,strength=8)">99th Pursuit Squadron

XyZspineZyX
06-23-2003, 04:09 AM
At low alt the finer the pitch the higher the rpm and thrust but as you gain alt youll want to make the pitch corser to get more of a bite in the thin air.Just know what the max allowed rpm for each motor which is usually the max thrust setting.


I was gonna ask about the supercharger allowing more richer mixture at higher alt and baldie jr answered/i/smilies/16x16_smiley-happy.gif

XyZspineZyX
06-23-2003, 04:15 AM
Bearcat99 wrote:
- <a
- href="http://mywebpages.comcast.net/Tailspin/index
- .htm"
- target=_blank>http://mywebpages.comcast.net/Tailsp
- in/index.htm</a>
- Cruise this site...lots of what you need to know.


Thanks for the link, lots of good stuff there.

XyZspineZyX
06-23-2003, 07:21 PM
Baldie: you're pretty much on the mark, but it's an over-generalization to say that 'in an engine, torque/hp increase with rpms'. That is simply not the case, especially in automotive engines. The engine will make max torque and max rpm at any number of places on the power band, depending on the design of the engine. The torque and hp curves go up to wherever the engine design makes them go, and meet at 5500 rpm...and then go on their own ways. My engine makes maximum torque at 2800 rpm (490 foot pounds) and maximum hp at 3500 rpm (340 hp) going to 4000 rpm will not increase my torque or hp...my redline is 5500 rpm, it's not a "max power point" it's a danger zone you don't cross while downshifting. It's the area "under the curve" that's really important. High rpms don't mean squat if the heads can't flow and the cam doesn't ramp. Just because you have a 6,000 rpm redline doesn't mean that your best shift point is at 6,000 rpm.

And superchargers are not just fans, I don't know where you got that idea...perhaps you're thinking of a turbine?

Not flaming you, just pointing this out

XyZspineZyX
06-23-2003, 07:59 PM
BBB462cid wrote:
- Baldie: you're pretty much on the mark, but it's an
- over-generalization to say that 'in an engine,
- torque/hp increase with rpms'. That is simply not
- the case, especially in automotive engines. The
- engine will make max torque and max rpm at any
- number of places on the power band, depending on the
- design of the engine. The torque and hp curves go up
- to wherever the engine design makes them go, and
- meet at 5500 rpm...and then go on their own ways. My
- engine makes maximum torque at 2800 rpm (490 foot
- pounds) and maximum hp at 3500 rpm (340 hp) going to
- 4000 rpm will not increase my torque or hp...my
- redline is 5500 rpm, it's not a "max power point"
- it's a danger zone you don't cross while
- downshifting. It's the area "under the curve" that's
- really important. High rpms don't mean squat if the
- heads can't flow and the cam doesn't ramp. Just
- because you have a 6,000 rpm redline doesn't mean
- that your best shift point is at 6,000 rpm.
-
- And superchargers are not just fans, I don't know
- where you got that idea...perhaps you're thinking of
- a turbine?
-
- Not flaming you, just pointing this out
-
-

When did auto engines matter in a flight sim?

Besides, engines that dont make max-power at max-RPMs are "trade-off" machines that never make absolute max power.

Think about it. The faster the engine turns, the more it can intake, meaning more mixture, therefore: more power. Just because you can detune a system to get power at a certain range does not mean you are able to make peak power at that range. Peak power always comes at the RPM prior to the engine going *poof*.

A super charger moves air from point A (outside the engine) to point B (inside the engine). It is, in its simpliest description, a fan. Compressor is actualy a better term, but not everyone understands the concept (90% people in the world have NO CLUE how this stuff works. Present things in non-elitists terms and suddenly the masses 'get it'.)

BuzzU: I don't see any reason to not leave with a hot engine. Your point is subjective and depends on too many factors to allow a one-size-fits-all answer. Sometimes I leave the fight, sometimes I don't. It really depends on the situation/ plane.




<font face="Courier New">
&nbspBaldieJr
_____ | _____
_\__(o)__/_
./ \.
Whiners don't play vulchers
(er, winners)
</font>

XyZspineZyX
06-23-2003, 08:03 PM
BaldieJr

I understand, but I didn't want him to think everytime the overheat warning comes on, he has to leave the fight. Especially if he takes care of it right away.

I have never left a fight becuase of a overheat warning, but I do something to cool it off right away. That was my point.

Da Buzz
---------------------------------------------------------------------------------------
Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be.... Adolf Galland
<center>
http://www.elknet.pl/acestory/foto1/hartm1-2.jpg

XyZspineZyX
06-23-2003, 08:24 PM
Automotive engine's don't matter in a flight sim. The principals behind internal combustion engine design don't change, though. It was the only example I could give, as I do not own any of the aircraft engines I rebuilt at school and I don't use them on a daily basis. I do, however, own that automotive engine I used as an example, and drive it a lot.

IC engines do retain similar features amongst themselves, however. No matter what the IC engine, torque and hp curves cross at 5500 rpm. They do not both go up after that, no matter what.

The speed an engine turns is not indicative of it's power output. The restrictive element is essentially airflow, not engine rpm. If the engine will not flow out more air at higher rpms than lower rpms, it cannot make more power, plain and simple.

The amount of air that goes in and out of the engine determines how much power, not the speed of the crankshaft. You do not start off with an engine that makes max torque and hp at max rpm and then "de-tune" it, you must make sure that the heads flow enough to support max power at high rpm (and I don't mean just horsepower by "power", I mean torque and hp, take your pick).



You state that (an aircraft IC engine, presumably) an engine always makes peak power just before it comes apart...could you quantify that, please, with an example of one, and where it makes max hp and torque? It's been a long time since I saw a Lycoming horizontal or R-2000 apart or seen one run up, and I can't remember their max rpms and powerbands off the top of my head. You seem to be telling me that if the aircraft engine in question has a 4000 rpm rev limit, it makes it max power (let's say at sea level) at 4000 rpm- both horsepower and torque is max at that speed, end of story.


I use no 'elitist' terms. I use the names of the things to describe them. No elitism, a fan isn't an impeller, and a compressor isn't an impeller. In my first post I did clarify by relating them to two large screws, however.

XyZspineZyX
06-23-2003, 08:42 PM
I whole-heartedly agree the manual for IL-2:FB is quite bad. There is a faq about CEM on mudmovers.com

XyZspineZyX
06-23-2003, 09:33 PM
Baldie- just thought of something

Are you confusing a rating like "2000 hp at 2400 rpm" to mean that the engine in question makes that power, and that rpm is the engine's redline?


I just looked up some stats on a R-2800, the Pratt and Whitney Double Wasp 18 cylinder radial displacing 2804 cubic inches which powered military aircraft such as the Corsair. That rating I gave, "2,000 hp at 2400 rpm" is the commonly accepted one for the R-2800. Pratt and Whitney claim that it could go to 2800 rpm, though, on their website.

XyZspineZyX
06-23-2003, 09:50 PM
BBB462cid wrote:
- A bunch of stuff.

Listen, the point is: system resonance means nothing to anyone reading this forum. I know, and you know, that intakes/ exhausts effect output power.

HOWEVER

Within the context of this discussion, motor-head tweaker-talk is totally wasted on the general public.

The facts, within context are: Higher RPM = Higher engine output. If anyone is really interested, here is a basic explanation as to why:

An engine is an air compressor. Simply stated, it moves air by buring fuel. The more fuel it burns, the more air it moves, etc etc etc (untill something goes BOOM). The faster the engine turns, the more air it can move, therefore the more fuel it consumes. If you limit the fuel, you also limit the air flow, and therfore limit RPMS.

Therefore, increasing throttle increases air intake, rpm, and output power. Any DETUNING placed into the system by inefficeint compontents is ignored within the context of this discussion.

A turbo or super charger is nothing more than a fan, in the interest of simplicity. Cram in more air, you can cram in more fuel, which equals faster spinning engine (RPM) which means MORE POWER.

<font face="Courier New">
&nbspBaldieJr
_____ | _____
_\__(o)__/_
./ \.
Whiners don't play vulchers
(er, winners)
</font>

XyZspineZyX
06-23-2003, 10:08 PM
Baldie, I guess none of my examples or supportive facts make much difference then.

P&W claim that their R2800 will do 2800 rpm, but independant sources claim the engine makes max power at 2400 rpm.

It has just dawned on me that you really aren't reading anything I post ("BBB462cid posted- a lot of stuff"), so trying to discuss this with you is largely pointless.

Max rpm means max airflow, eh? Any engine will 'run out of breath' if the heads don't flow- but that doesn't mean it can't rev. As I've said, rpm isn't the problem, it's head flow. If you're still reading this, would you care to post some head flow numbers for a specific engine at specific rpms up to redline?


Again, you say that max torque AND max hp come at max rpm, and the only fact that you can come up with is that more speed for the rotating mass means more power. You mean to tell me that the torque and hp curves just go up until redline, and I'm still waiting for proof from you, is all.

Message Edited on 06/23/0310:13PM by BBB462cid

XyZspineZyX
06-23-2003, 10:56 PM
BBB462cid wrote:
- More off topic stuff that happens to be prefectly at home
- in a automotive forum.

I have read your posts. I'm not arguing system inefficiencies or your 'level of correctness'. You is right, be sure.

What I am arguing: For all practical purposes, none of what you are saying matters. When we all move ourselves to a racing forum, i surely hope we split these hairs there.

While in the context of this particular discussion, speaking purely of FB, HIGH RPM = MORE POWER.

If we simply must take this discussion of into a tangent...

Remind yourself: either engine type can be built. You can build one that developes more power at low RPMs, and I can build one *of the same displacement* that makes power at high rpm. Assuming we've both designed our engines withing structural limitations, and with either engine tuned for best power at thier designed operating speed, mine will produce more power than yours because mine turns faster (flows more air/ fuel).




<font face="Courier New">
&nbspBaldieJr
_____ | _____
_\__(o)__/_
./ \.
Whiners don't play vulchers
(er, winners)
</font>

XyZspineZyX
06-24-2003, 01:55 PM
So I'm talking about automotive engines because YOU say so?

May I ask what experience you have with aircraft engines? If you have more than I do (I have rebuilt 3 horizontals and disassembled a radial at engineering school, we didn't have parts to correctly reassemble the radial, plus I have rebuilt any number of secondary systems, ie: accumulators, carburetors, piston pumps, etc. not to mention wingboxes and control surfaces, control cables and hydraulic systems) please explain to me how what I am talking about only applies to non-aircraft engines. I have also rebuilt automotive engines, and not for the grocery-getter economy car, unless a 7 and a half liter performance engine is what you'd expect in a Honda.


But none of that matters, you say. Fine. Then let's both stick to the point.



Let me again state what I am refuting:

You say that maximum torque and maximum horsepower come at maximum rpm. That torque and hp curves go up until redline. Didn't you post that? isn't that what I've been talking about all along? Maximum rpm means maximum horsepower and maximum torque.

I say that is not so, and again I ask for examples to back up your statement. Particularly regarding torque, a misunderstood beastie if there ever was one.


Suddenly, you revise your statement to mean "Only in FB". Ok, examples of torque and horsepower curves in FB-modelled engines, please.

remind yourself: you do not need to be at full power to accellerate, and you do not need to be at full throttle to accellerate.

PS: you are now the only speaking in "motor head talk" and of racing, delving into cam and head selection for your "air/fuel" flow. And by the way, your example of each of us building an engine does nothing to validate your standpoint that max power comes at max rpm. You yourself merely indicate more power at higher rpm, something I am not refuting. Your example does not address the principal issue: max horsepower and max torque at max rpm.

All I am asking you for is some examples to back yourself up. I have given you my example, the R-2800 engine is rated at 2000 hp at 2400 rpm, but it's manufacturer says it will rev to 2800. Now, if you please, provide me with your example and your source.




Message Edited on 06/24/0302:22PM by BBB462cid