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View Full Version : Oleg Sir, I would like to have 2 important questions about future FM charasterics



Maggi_4
03-11-2006, 09:20 AM
1. Will be high altidue engine perfomance modelled in future patches?
Jets are obviusly slow and clumsy above 5k, Ta152 is known for its great service celling. I guess it is useless to continue the explaining list with P51, P47, Fw190A, P40, and some russian aircraft why is this changing is necessary.


2. Will be aircrafts weight modelled in future patches?
For example I never felt I can leave anyone in a P47 in a flat dive. Against a D9 I felt only the horizontal accelatrion showing up.

Sorry for so bad english

JG4_Helofly
03-11-2006, 11:23 AM
The chance that Oleg respond on that topic is 0.000001% http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Probably he will never say such things before release.

heywooood
03-11-2006, 01:04 PM
I think these are two great questions...High altitude atmospheric modeling is critical for solid BoB simming.

Aircraft weight being modeled correctly is necessary too, especially the changes in aircraft weight as fuel is consumed and ammo exhausted.

OldMan____
03-11-2006, 01:39 PM
Weight IS modelled. There is no way you can model it wrong in a simmualtion like this, since is a SINGLE line of code.

Several tests already proved taht. What we have is a dominance of POWER acceleration over graity acceleration when compared to waht people would expect from anedoctes and etc...


So the things that might eb off are DRAG and thrust.

Luftkillier
03-14-2006, 08:03 AM
The lack of a proper high alt flight model has made certain planes useless(ie. MUSTANG). It sure would be nice to have this kind of thing corrected in FB. http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

VVS-Manuc
03-14-2006, 08:49 AM
The max. altitude on the usual online-DF-server ist 3.000 ft...so don't worry about the P-51 http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

VMF-214_HaVoK
03-14-2006, 02:16 PM
Originally posted by VVS-Manuc:
The max. altitude on the usual online-DF-server ist 3.000 ft...so don't worry about the P-51 http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

3,000 feet? LOL! Obviously we fly in different servers. The ones I fly in that is not even the minimum. Try Zekes vs Wildcats or Spits vs 109s and see how long you last at 3000 feet. I dont care what you are flying.

ImpStarDuece
03-14-2006, 03:34 PM
For all of theose poo-pooing the FM, please remember that Oleg has stated that altitude is modelled until 10,000 meters/33,000 feet and after that it becomes essentially static.

In all my time flying IL-2 online I have had 3 fights above 9,000m. Twice in P-47s and once in a Spitfire IXc each time against Ta-152s. Offline, I have flown the TA-152 up to around 12,000 meters before it stalled out completely. Thats around 900m short of its rated altitude historically.

I don't think that there is really anything wrong with the altitude modelling, its just that people unrealistically expect to be able to manouver at 7500m the same way they do at 2500m. Unless your fighitng over 10,000m, you should be fine.

Maggi_4
03-14-2006, 05:36 PM
Back to weight:
I think than it's not modelled correctly. A 109 can easily stay with a P47, or even take it over...Not even mentioing zoom climb...P47 is an obvius example there is something wrong with weights in this sim.

No matters which server you are flying at, I don't think that realistic high alt performance can be bad for those people who fly under 1000m. But I know there are many pilots who fly above 1000, 6000, and I would fly over 9000 too if that would worth something (in a Mustang for example)

Pls 1 more thing: When you read this don't start thinking from DF servers, and so on. Check it out from Online War's perspective. Obviusly you ll fly above 6-7k...

TY

Sorry for so bad english

Jetbuff
03-15-2006, 04:02 AM
Maggi, we've been over this. Weight is modelled. This has been proven. What might be off as Oldman said is thrust/drag modelling, both of which contribute to dive acceleration. Indeed, thrust is more important than weight in determining initial dive acceleration and parasitic/cross-sectional drag is more important than both put together.

WWMaxGunz
03-15-2006, 09:03 AM
Originally posted by Maggi_4:
Back to weight:
I think than it's not modelled correctly. A 109 can easily stay with a P47, or even take it over...Not even mentioing zoom climb...P47 is an obvius example there is something wrong with weights in this sim.



Maybe an example of drag instead. Like prop drag if you try and go fastest with CSP pitch
at 100%. People who cut way back in dives from speed level max do dive faster. 109 auto
pitch gets it right without pilot attention but CSP users ignorant of 100% pitch is NOT the
best way to fly even past 500kph will never get the best speed out of their planes.
I don't know how you control it but I've devicelinked and compared enough dives data to say
that dives are different but you get out only as good as you fly it. The best speeds take
knowing that one plane extremely well with attention to the flying only, not one eye on the
guages 10% of the time. You do all that? You have tracks and logs to make a case?

diabloblanco1
03-15-2006, 09:21 AM
ROFTL! Ok, take a flight of P-51's and P-47's set them to 9,000 meters and 350kph. Set a flight of B-17's at 10,000 meters and 350kph a click ahead of the fighters.Now, try to catch them. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Then setup a flight of 109's or 190's to attack the bombers. Now try to fly and protect them. http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Something is denfinetly off with the high alt model in this game, or something with specific planes at high alt. Even the planes that were historically better at high alt fly like lawn darts.

NonWonderDog
03-15-2006, 11:01 AM
Speeds in FMB and QMB are TAS... 350 km/hr TAS isn't very fast at 10 km - only about 220 km/hr IAS depending on ambient temperature.

You do a bit better if you climb to altitude instead of spawning at 10 km at nearly stall speed.

That's not to say everything's correct, of course. I really don't know what it should be like.

What do the airspeed indicators say at high altitude? You might be able to get an idea of the modelled air density from IAS and TAS readings.

WWMaxGunz
03-16-2006, 12:12 AM
Originally posted by diabloblanco1:
ROFTL! Ok, take a flight of P-51's and P-47's set them to 9,000 meters and 350kph. Set a flight of B-17's at 10,000 meters and 350kph a click ahead of the fighters.Now, try to catch them. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Then setup a flight of 109's or 190's to attack the bombers. Now try to fly and protect them. http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Something is denfinetly off with the high alt model in this game, or something with specific planes at high alt. Even the planes that were historically better at high alt fly like lawn darts.

Where you set the LW planes up? 10km? 11?

Try escorts and interceptors at 27000ft and bombers at 25000ft. The escorts are roving,
speed should be IAS 250mph or more, same with interceptors. Escorts don't travel lower
than the planes they are guarding, they travel above.

CyC_AnD
03-16-2006, 03:08 AM
I don't want to be harsh, but where you guys studying physics if you think that weight matters for acceleration in dive?
Only things that matter in dive is drag and engine power(or maybe propperler type). Every object falling down with about 10m^2 no matter how heavy. Only limit is it's aerodynamic profile. Same with zoom climb...
That's why a high wing loaded planes should have advantage over low loaded counterparts. Bigger wings, bigger drag.

Sorry for my english.

OldMan____
03-16-2006, 01:22 PM
Sorry you are the one that need to study physics.


In atmosphere, thwo objects with same drag, the ones with greater mass will accelerate faster.

People should make calculations instead of just try to repeat basic school teachings.

WWMaxGunz
03-16-2006, 02:28 PM
What Old Man says, only more detail. Once drag stops freefall and by how much it does, weight
becomes a force against the drag and same plane but heavier will fall faster. When I went
to school this was known earlier than high school for those who showed interest. We made
rockets and flew them 5th and 6th grade as part of the learning of practical approach.

What they teach you, CyC_AnD?

sensen13
03-16-2006, 02:37 PM
Sorry but weight (mass) is not a factor in dive acceleration. True, if a P47 had twice the mass of the 109 pursuing it, the gravitational pull between the Earth and the P47 would be double that of the forces involved with the 109. However, you are forgetting the basic observation of "a body in motion tends to stay in motion and a body at rest tends to stay at rest".

The mass of the two planes in question require a proportionate amount of energy to accelerate them in the direction of the dive. Due to its mass it would require twice the energy (provided by gravity) to accelerate the P47 into the dive. Remove the atmospheric effects (drag and thrust) and the two aircraft will accelerate at the same rate.

Weight is not a factor, thrust and drag are(drag being the greater of the two).

EDIT: What Gunz is refering to is called terminal velocity; a body in freefall will reach a speed at which the effects of drag will negate any further acceleration. In this case, all other things being equal, the body with more mass will reach a higher velocity due to the greater energy invoked by gravity. However this is at the extremes of a dive and not a consideration in the case of acceleration. With out hard numbers I cant say for certain whether any plane can achieve terminal velocity but I suspect that most WWII aircraft would loose structural integrity long before reaching the speeds involved.

OldMan____
03-17-2006, 09:40 AM
It impressive how so many people stick to this weight does not matter in dive acceleration. It DOES, in atmosphere it does.


Prof:

Plane A 10000kg plane B 20000kg. Bothe have EXACLT same drag coeficient and size, so same drag when at same speed. Lets suppose (just for the sake of easy calculation) that drag in newons equals 10 times the speed in meters per second.


So they both start at 100 m/s. Plane A has 2 forces acting upon it, Drag that equals 1KN and weight that equals 100KN. The resulting force is 99KN. That is capable of accelerating 10000kg at 9.9m/s2.

The second plane has same drag so 1KN. But weight is 200KN. The resulting force is 199 KN. This force is capable of accelerating 20000kg at 9,91m/S2.

That is a small difference, but drag in real life is much higher and the difference will be even higher.

NonWonderDog
03-17-2006, 12:21 PM
Originally posted by sensen13:
EDIT: What Gunz is refering to is called terminal velocity; a body in freefall will reach a speed at which the effects of drag will negate any further acceleration. In this case, all other things being equal, the body with more mass will reach a higher velocity due to the greater energy invoked by gravity. However this is at the extremes of a dive and not a consideration in the case of acceleration. With out hard numbers I cant say for certain whether any plane can achieve terminal velocity but I suspect that most WWII aircraft would loose structural integrity long before reaching the speeds involved.

Planes reach terminal velocity in level flight... whenever you stop accellerating you've approached your terminal velocity (by definition). You just get more force pulling you forward, and a greater terminal velocity, when you point the nose downwards.

You admit that heavier planes will reach a higher terminal velocity in a dive, but it's impossible for one plane to reach a higher terminal velocity than another without having greater accelleration at some point of the flight. This should be self evident. The greatest accelleration difference will come late in the flight, but if the two planes were at maximum level speed before initiating the dive, the heavier plane will accellerate noticably more quickly.

The difference in dive accelleration between two similar planes really should be almost nil in a vertical dive, as terminal velocities would be so high anyway, but in a 30 degree dive the heavier plane will win, all else being equal.

I'm not sure if any of this has any combat relevance, though. Power/weight ratios and drag coefficients are much more important.



To anyone that still doesn't understand: drop a feather, then drop the same feather with a paperclip attached to it. The heavier feather will fall faster, because of the effect of air drag. Same principle here.

sensen13
03-17-2006, 05:55 PM
The example of the feather does not show that greater weight equals greater acceleration.

Terminal velocity, by definition, is the velocity at which an object in freefall will no longer accelerate. This is the result of the net effect of drag (both induced and parasitic; which increase with the square of velocity) reaching a point equal to the forces of gravity.

The unclipped feather's weight to drag ratio results in a low terminal velocity, so it falls slowly. The clipped feather has a greater weight to drag ratio and therefore has a greater terminal velocity (and don't forget the effect the clip has on the feather's aerodynamics, which affects its induced drag). As you can see, the clipped feather will fall faster because it has a higher weight to drag ratio (a higher terminal velocity).

Oldman's example better illustrates the effects of the weight to drag ratio, and I was in error (thinking like the astrophysicist I am, despite having the knowledge to prove otherwise).

Drag will reduce the effective force of gravity and therefore, all other things being equal, the heavier plane will gain a small increase in acceleration.

However, the numbers he used are an over simplification and do not show the true effects involved. Furthermore there is an error in stating that a higher drag coefficient will result in an increased variance in the accelerations. In fact the higher drag will result in a smaller net downward force and the variances will likewise be reduced (though they would would remain proportional).

As it is, the current example only gives a 1 milimeter per second squared increase to the heavier craft and the true numbers would be significantly less.

All this goes to show that weight is not as significant a factor in dive acceleration as some make it out to be (though it does have an effect) and that the modeling of drag (and thrust) are what need to be addressed in order to rectify in-game flight models to real world flight characteristics.

NonWonderDog
03-18-2006, 09:51 AM
Of course the feather analogy is valid. If you drop the normal feather and the heavy feather at the same time, the heavier feather will continue accellerating after the light feather has reached terminal velocity -- i.e. the heavier feather will have greater accelleration than the light feather at some point in the fall. I can make a couple graphs if you really want, but I'm sure you understand.

If you start a dive in a plane at max level speed, you are already at a terminal velocity. Pointing the nose downwards will increase that terminal velocity. The heavier plane will have a greater increase in terminal velocity, and will thus be able to accellerate faster than the lighter plane as long as they are somewhat close to their new terminal velocities already, as in a shallow dive.

This is not just idle speculation, planes most certainly *DO* reach terminal velocity in dives less than 45 degrees or more. Think about gliders -- gliders carry ballast in order to let them travel faster. The heavier glider will travel the same distance, it will just get there faster. (I'm a student aero engineer, don't argue. Adding ballast to a glider will not decrease gliding range without the effect of thermals.) A plane with an engine is subject to all the same laws.


All this really shows is that a fully-laden P-47 will dive better than an empty P-47, though, and I don't think that's useful at all. Being heavier than your adversary is not an advantage in combat, especially if you're in different planes.

sensen13
03-18-2006, 12:34 PM
Yes, I understand that the heavier feather will continue to accelerate once the lighter one reaches terminal velocity and therefore will at any given instance, other than the outset, exhibit a greater acceleration. But in this instance both the weight and the drag are varied. That is why I say the example is not valid. There is no control; no factor that the two drops have in common to determine whether drag or weight is affecting the rate of acceleration. You might as well drop a brick and a feather.

Please understand; regardless of weight, any two objects will have an equal amount of force applied by gravity which results in a constant (and equal) rate of acceleration in the absence of a drag inducing atmosphere. It is the effects of drag that are the determining factor in reducing that rate of acceleration.

Unfortunately I dont have time at this moment to go into the details further, but dust off you slide rule, for I will return with examples that show how much of a difference drag coefficients have over weight in dive acceleration.

pourshot
03-18-2006, 01:06 PM
Finally a subject debated logically and intelligently without the need to resort to insults, I look forwards to reading the replys. http://forums.ubi.com/images/smilies/25.gif

Aaron_GT
03-18-2006, 01:55 PM
"a body in motion tends to stay in motion and a body at rest tends to stay at rest".

What Newton actually said is that this is the case unless there are forces acting on the body. In the case of aircraft in the gravitational field of the earth there are a number of forces acting - lift, drag, gravity, and thrust, essentially.

Drag varies between aircraft and velocity, but at any given velocity it is roughly proportional to the square of the size of the plane, whereas the mass is roughly proportional to the cube of the size, and so the force due to gravity also scales roughly as the cube. Thus the drag on a small object is a greater proportion of the total forces acting than for a large object.

Aaron_GT
03-18-2006, 02:02 PM
But in this instance both the weight and the drag are varied.

The drag at any given speed will be the same for the feather with or without the paperclip. What is different is the balance of the force due to gravity (which is proportional to the mass) and the drag. a = F/m, or a = (mg - D)/m where D is the drag, g is the acceleration due to gravity, i.e. a = g - D/m.

In reality D will be D(v), i.e. a function of the velocity.

Terminal velocity occurs when D(v) is the same as mg. Since mg is larger for the feather with paper clip and given that D tends to increase with v (roughly as the square of velocity) the feather with paperclip will fall fastest. The grag profiles with and without the paperclip are essentially the same.

WWMaxGunz
03-18-2006, 10:50 PM
The heavier feather has a higher PE at any altitude. Drop the same alt, the heavier one
will have shed more energy against drag. It's gonna fall faster.

Sensen:
Heavier object, higher PE, same gravity. Only same freefall accel, not same energy.
Add air and you have what's behind the accel to consider.

WWMaxGunz
03-18-2006, 11:12 PM
Originally posted by sensen13:
Sorry but weight (mass) is not a factor in dive acceleration. True, if a P47 had twice the mass of the 109 pursuing it, the gravitational pull between the Earth and the P47 would be double that of the forces involved with the 109. However, you are forgetting the basic observation of "a body in motion tends to stay in motion and a body at rest tends to stay at rest".

The mass of the two planes in question require a proportionate amount of energy to accelerate them in the direction of the dive. Due to its mass it would require twice the energy (provided by gravity) to accelerate the P47 into the dive. Remove the atmospheric effects (drag and thrust) and the two aircraft will accelerate at the same rate.

Weight is not a factor, thrust and drag are(drag being the greater of the two).

EDIT: What Gunz is refering to is called terminal velocity; a body in freefall will reach a speed at which the effects of drag will negate any further acceleration. In this case, all other things being equal, the body with more mass will reach a higher velocity due to the greater energy invoked by gravity. However this is at the extremes of a dive and not a consideration in the case of acceleration. With out hard numbers I cant say for certain whether any plane can achieve terminal velocity but I suspect that most WWII aircraft would loose structural integrity long before reaching the speeds involved.

No.
No.
No.

I was referring to the simplified elements and dynamics of falling in air, note nothing on
Reynolds numbers or vortecies?

You can't be in freefall unless you can match freefall acceleration. As soon as drag becomes
more than negligible and thrust can't counter it totally you get no freefall. Anywhere near
TV you have already left freefall. Drag is not something that waits for TV. It is a dynamic.

And for WWII aircraft reaching TV without breaking up... yeah some early ones could no problem.
And the record dive planes occasionally came out in one basic landable piece. They went for
mach numbers under power, there's a late Spit that hit .89 officially recorded. P-51 hit .84
over Wright Field I've read of. Don't think either one flew again once the engineers got to
em.

Xiolablu3
03-19-2006, 06:08 AM
Weight makes NO difference to acceleration/fall speed.

Take a cricket ball and a tennis ball of the same diameter. The cricket ball is around 5 times heavier, but it will fall at exactly the same speed as the tennis ball as long as there is no wind.

Its a common misconception that heavier objects fall faster.

SOrry guys who say heavier means faster, you are wrong. Simple Secondry school physics..

Evidence :-

http://physics.about.com/cs/mechanicsexp/a/241003.htm#
http://einstein.stanford.edu/content/education/EducatorsGuide/Page26.html

EDCF_Rama
03-19-2006, 07:12 AM
Originally posted by Xiolablu3:
Weight makes NO difference to acceleration/fall speed.

In vacuum, you're right (since Mass can be eliminated on both side of the force equation)
In air.... you're totally wrong...

A simple demonstration based on the force lead to this formula for a sphere (neglecting air perturbation and some other stuff...)

a = g - (Pa/m) - (6*Pi*Vis*R*v/m)

with
a= acceleration applied to the ball
g= gravity acceleration
Pa= Archim├┬Ędia pressure (negligeable for a plane or even a ball... but not negligeable for the feather... that's the only reason I place this term here)
m= mass
Pi=... well, you know...
Vis= Air viscosity
R= Ball ray
V= Ball speed

You can see that in vaccum (no Air), you have Pa=0 and Vis=0
... stay a=g, and so all objects fall at the same speed (V=gt) regardless of Mass.


Take a cricket ball and a tennis ball of the same diameter. The cricket ball is around 5 times heavier, but it will fall at exactly the same speed as the tennis ball as long as there is no wind.

Totally wrong if in air (see above)


Its a common misconception that heavier objects fall faster.

Well... no, it's a common right conception (in some cases it's wrong, but only because of drag)

But it's a common misconception among peoples having some partial memories of physic lessons that all objets fall at the same speed, regardless of Mass (they just forgot it's only in vacuum)


SOrry guys who say heavier means faster, you are wrong. Simple Secondry school physics..
I agree the above is simple secondary school physic.... and demonstrate you're wrong...

carguy_
03-19-2006, 10:07 AM
I`m sure that if Oleg is reading this he`s LMAOing on some of you.

Not that I understand anything that is written here. http://forums.ubi.com/images/smilies/bigtears.gif

Aaron_GT
03-19-2006, 10:13 AM
In the middle ages it was commonly thought that heavier objects fell faster (or spent less time falling a given distance, to be accurate). When considering real world objects dropped such that they meet terminal velocity this was a reasonable first approximation as it tends to account for air resistance. When Galileo conducted his famous experiments he actually tried to control for air resistance by rolling cannon balls of various sizes rather than dropping them. This tends to reduce the relative effect of air resistance.

WWMaxGunz
03-19-2006, 12:58 PM
Originally posted by Xiolablu3:
Weight makes NO difference to acceleration/fall speed.

Take a cricket ball and a tennis ball of the same diameter. The cricket ball is around 5 times heavier, but it will fall at exactly the same speed as the tennis ball as long as there is no wind.

Its a common misconception that heavier objects fall faster.

SOrry guys who say heavier means faster, you are wrong. Simple Secondry school physics..

Evidence :-

http://physics.about.com/cs/mechanicsexp/a/241003.htm#
http://einstein.stanford.edu/content/education/EducatorsGuide/Page26.html

Secondary school physics ....... really when the balls were dropped in Pisa and the Old Way
of Understanding took a big hit, it was a triumph for mankind.

BUT. Those balls never reached speed where drag was a factor relative to weight. Nothing of
drag or flight was shown that day. Perhaps if he had dropped a balloon instead we would not
be using PC's?

Xiolablu3
03-19-2006, 06:23 PM
Oooops, yes, I was wrong it seems.

I just found a link about the subject,

http://answers.google.com/answers/threadview?id=448350



Well I learned something today, Just ignore me. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

WB_Outlaw
03-21-2006, 12:43 PM
Originally posted by sensen13:
Please understand; regardless of weight, any two objects will have an equal amount of force applied by gravity which results in a constant (and equal) rate of acceleration in the absence of a drag inducing atmosphere.

I hate to tell you this but weight IS the force exterted by gravity. Two different weights, two different forces.

It's the acceleration due to gravity that is constant IF the ONLY force that is exerted on a body is the force of gravity.

I'm starting to sound like a broken record but all it takes to understand this dead simple issue is a free body diagram. It take 5 seconds to draw if you already have a pencil in your hand.

--Outlaw.

Jetbuff
03-21-2006, 01:36 PM
weight = force

force = mass * acceleration

acceleration due to gravity is constant

Hence the confusion. However, keep in mind that unless you are operating in a vacuum, weight is only one of many forces acting on the object. Thus the net vector force is different and therefore acceleration is not necessarily constant for different mass objects. (or even same mass objects with different drag profiles)

For a very simple analogy, consider level acceleration instead. Here, the force is not weight but thrust although it is similarly opposed by drag. Forthe same thrust/drag values two objects will attain the same top speed. However, if you increase the thrust, top speed (as well as acceleration) increases. That is essentially what happens with a heavier aircraft in a dive - more weight = higher force just like thrust. Of course it is tempered by the fact that because it is dependent on an increase in mass which means the gain in acceleration may not be as appreciable as some would expect.

JG4_Helofly
03-22-2006, 03:08 PM
So their is only a advantage at high velocity?
In the test fw 190 A3 vs. spit Vb

"Dive: Comparative dives between the two aircraft have shown that the FW 190 can leave the Spitfire with ease, particularly during the initial stages. "

The question is at what speed was it? It would be mentioned if their were great differences at different speeds. Don't you think so?

WWMaxGunz
03-22-2006, 09:15 PM
Can you attach any numbers to 'leave' in that statement?

Add thrust and excess thrust to mass to your dive, consider that thrust overcomes drag at a
variable rate up to level max speed and then add your weight as a factor, looking forward to
yet another equation here.

Did the Spit and FW run what power? Start at what speed? Anything on prop settings?
Big news flash, not everyone who designed, tested or flew is or was a total expert on every
detail. I've seen P-47 report saying 'only by diving' if an enemy is on the six. But P-47
Ace Johnson told that every time what he did was zoom climb and if the enemy did not run
then he engaged and made the kill. But he must be wrong because Official Report says other.
WTH, it's just duelling anecdotes... I could show either here to 'prove' what is right and
if no one says otherwise I could still be wrong.

horseback
03-23-2006, 02:02 PM
In general, "leaving" would constitute putting about 250m between the 190 and the pursuing Spitfire, which was about the greatest range at which its wing mounted guns would be effectively "aim-able" for the average veteran pilot.

With a 30mph constant speed advantage, it would take over 15 seconds (or a couple of lifetimes in combat) for the 190 to reach that distance, so I suspect that if we assume that even starting at the same level speed, the 190 does the flickroll and dive maneuver getting at least a couple of seconds advantage over the Spitfire entering the dive, and as he accelerates to terminal velocity, obtains much greater than a 30mph speed advantage fairly quickly (before the average Spit pilot can line up a shot), pulling away and out of practical firing range almost immediately.

All of these tests were done with an eye to their practical application to combat; in combat, that FW doesn't start his roll and dive at the same speed and level with the Spitfire or on the same signal. He is most likely to be some distance ahead and the Spit driver has to react when the FW begins his roll (and the FW rolls much better than the Spit).

He accelerates better initially, adds a little rudder and/or elevator, and he's gone, unless the Spit driver can manage to keep him in sight until he starts his pullout (and probably loses track of his pursuer). In 1942-43 combat, extended pursuit is usually more perilous than looking for another target, so nine out of ten times the FW escapes the Spit V.

When you get to the P-47 or P-51, which usually started with better speed and accelerations at higher altitudes, coupled with greater mass and lower drag than usually credited, most of the aces seemed to think that in a worst case scenario, if they pursued an FW or 109 from 30,000 ft with the pursued a/c having up to a 1600m (5200ft) advantage, they still could catch it within 15,000 ft.

In 1944 high alt combat, the speeds of the diving aircraft largely precluded intervention by latecomers, so the initial flickroll and dive maneuver provided less of a margin for escape...

cheers

horseback

WWMaxGunz
03-23-2006, 06:22 PM
I think you make assumptions about 'leaving' but at least you do have the effect of quicker
start on maneuver correct. I've seen one place where "much greater" got numbers attached
in text and it wasn't much greater in terms of percent of speed or range at all but in terms
of human scale, that was a reference in level accelerations. Unqualified, meaning no numbers
attached and not something about the observer, observations in reports are near useless for
us or sim makers is just how it is yet we see the posts anyway.

Consider that on the highway if you are going 60 and get passed by someone going 75 that it
may be described as having your doors blown off or other suitable putdown and yet if you are
going 90 and get passed by the same margin it still comes to the same adlib evaluation. That
is human terms. It is also in the envelope of dive speed differences in a 2-3 km dive by,
well the example given me was a P-47 and FW-190 in a too often quoted dive comparison report.
Much greater there just don't match what so many want.

Yeah first one rolled gets to use his lift to change direction and that lift is multiple G's
for a short time. I dunno if the test people do that but the pilots sure did. By the time
the Spit has rolled he has passed the point the FW did unless he was a long ways back and
has to recover that distance too. Much more real to leaving an enemy behind as noted.

CMHQ_Rikimaru
03-25-2006, 09:10 AM
Weight doesnt affect dive acceleration?
force = mass*10
So if plane's weight is 4000kg, so the force affecting this plane is 40000N. When plane's weight is 2500kg, force is 25000N. And u guys still dont see any difference? This force is constant, all the time....

hop2002
03-25-2006, 10:47 AM
Acceleration = force/mass

The more massive plane gets more force, but needs more force for the same accleration

4000 kg plane:

aceleration = 40000 N / 4000 KG

2500 KG plane:

acceleration = 25000 N / 2500 KG

What makes a difference is the amount of prop thrust, and drag. Whithout those 2 factors, all planes will accelerate at the same rate. With them, the picture is complex, because prop thrust reduces as speed increases, and drag increases with speed.

CMHQ_Rikimaru
03-25-2006, 01:52 PM
But, are u considering a proportion of drag to the gravity force? Lets say that while flying 300km/h drag force for both AC is 10000N. Then both of them starts to dive, drag slowing down the first one is 4 times less, than gravity. Force slowing second one is 2,5 times less, than gravity. Do u see a difference? So its easy to see that force left to accelerate plane A is 30000N/4000KG, and plane B is 15000N/2500KG http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

NonWonderDog
03-25-2006, 04:42 PM
Yes, and that's what most people in this thread have said all along.

WWMaxGunz
03-25-2006, 11:06 PM
Except the 4000kg plane may be running 15000N drag due to size alone to the 10000N of the
2500kg plane. But 2500/4000 is still more than 1500/2500, but only 625:600 instead of
750:600.

CMHQ_Rikimaru
03-26-2006, 01:30 AM
Ofcourse Max, but im trying to convice that weight is important both in diveing, and in zoom climbing ability, drag was just an example(4000 weight was FW190, 2500 was Yak3http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif). We dont know true drag factors, even if plane have radial engine, there are special tricks that can reduce draghttp://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Im trying to not use a lot of physical formulas, and not write 100 lines of text, because its hard to understand what about this guy is talking. Its especially hard because even if most of us speak english well, we would not understand physical terminology.

WWMaxGunz
03-27-2006, 12:38 AM
I'd just like to try and clear up some whys the straight race dives people want to see big
results in seconds won't get them. And we have nothing of thrust or excess thrust that at
less than very high speeds may give the lighter plane the initial advantage. Brit compare
of captured FW in dive with P-47 over 7,000ft alt lost and the P-47 did not even catch the
FW until the bottom where it was noted it had greater speed. Both were throttled to give
400kph start and left to that where FW in real may have had even more start advantage if
both allowed to go full power. Players who don't know of that cry if P-47 is not 300m
ahead in the first km travel or less, the posts are like they should count to three and
be out of range. That's how the books read, after all. Should be more words in those books.

CMHQ_Rikimaru
03-27-2006, 01:43 AM
Max - im not sure that everyone want to outdive others with just 3 seconds. We simple just cannot outdive or outzoom-climb planes, that should be outdived.

WWMaxGunz
03-28-2006, 01:46 AM
People have been saying that for years with many saying there is no difference for perhaps
extra word effect. Many tests have been run and tracks used to get devicelink data. What
I have seen is that with proper prop pitch management that the planes do dive faster max
speeds or just reach breakup sooner.

I read from AVG site what Eric Schilling had written. P-40 would hit with speed 240+ mph
and then roll over and split-S dive to avoid Zeroes in the Pacific. Why the Zero could not
follow was not speed but inability to roll at those speeds. The P-40 could change direction
even during the dive much faster than the Zero if it followed. The P-40 could exit the dive
and reverse the attack on a Zero that tried.

I read Saburo Sakai and #1 I see is poor roll at high speed but yes, #2 is lower top speed
in a dive. Were all Zeroes the same at dive speed? I do find that with proper CEM the
dives do end up with more spread even if it is not much as percentages. I find it is about
top speeds and time in straight dives. In the climbs after dives I got from Robban is
where I found the big differences.

Shame we don't see historic detailed data on diving for all these planes, but there should
be for some few used for record attempts. Problem to me is the records were gone for at
over 10km alts.