PDA

View Full Version : Pe2 - new king of diver?



Kwiatos
05-01-2006, 11:16 AM
Pe2 in 4.05 could dive up to 900 km/h IAS without no damage. So have we new tactic to fight with Fw190s and 109s?

JG53Frankyboy
05-01-2006, 05:20 PM
the Ju88 can also reach 900km/h IAS.

a little bit weird in comparison with the Mosquito, Beaufighter, Bf110G wich break up long before they reach 800km/h !
espacially for the Pe-3 fighter a tactical advantage......

p1ngu666
05-01-2006, 06:04 PM
the mossie starts shaking at 400mph or so doesnt it?
i remmber it being rather "early" anyways.

p1ngu666
05-01-2006, 06:43 PM
mossie
370mph it starts shaking

740kph it falls to bits

pe2, 900kph falls apart

btw, with different engines the VI could do 366mph @ SL, with just 18lb boost
in PF world, 25lb boost speeds would have the plane shaking all the time http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

ImpStarDuece
05-01-2006, 07:42 PM
Bah Pingu, thats slow.

The Mk. XXX could do 377 mph @ 2000 feet, and 394 mph at 2000 feet with N20 injection http://forums.ubi.com/images/smilies/784.gif

The used the Mk. XXX to chase down V1s in level flight http://forums.ubi.com/images/smilies/11.gif

p1ngu666
05-01-2006, 07:44 PM
http://forums.ubi.com/images/smilies/59.gif

J_Weaver
05-01-2006, 07:56 PM
Originally posted by p1ngu666:
mossie
370mph it starts shaking

740kph it falls to bits

pe2, 900kph falls apart

btw, with different engines the VI could do 366mph @ SL, with just 18lb boost
in PF world, 25lb boost speeds would have the plane shaking all the time http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Yup, something seems a bit off with the Mossie. Has anyone else noticed that she seems quite nose heavy?

AWL_Spinner
05-02-2006, 04:09 AM
No way you'd ever dare follow a Ju88 into a dive in a Mossie in-game, and you have to moderate diving attacks quite considerably.

For safety in the pull-out I keep my Mosquito at 400-410mph, not a bit over or it crumples.

The Pe-2 is a fun plane going downhill, no doubt. The Mosquito is a little sturdier in the face of ground fire, seemingly.

Kwiatos
05-04-2006, 03:43 AM
I made short dive test:

MAximum safe speed IAS:

Pe2/3 - 900 km/h

Ju88 - 850 km/h

Moskito - 710 km/h

For comparison fighters:

Fw190 A-4 - 870 km/h

P-51 D - 900 km/h

Tempest - 910 km/h

P-11 - 450 km/h

Wow Pe-2/3 are better then even Fw190 http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif and as good like P-51 and Tempest.

p1ngu666
05-04-2006, 10:32 AM
plus u cant snap the wings off so easy as with p51 and tempest, so subjectivly, pe2 is king of divers http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

WWMaxGunz
05-04-2006, 01:03 PM
Originally posted by AWL_Spinner:
No way you'd ever dare follow a Ju88 into a dive in a Mossie in-game, and you have to moderate diving attacks quite considerably.

For safety in the pull-out I keep my Mosquito at 400-410mph, not a bit over or it crumples.

The Pe-2 is a fun plane going downhill, no doubt. The Mosquito is a little sturdier in the face of ground fire, seemingly.

Mossie is made almost all out of?

I had read long ago that Mossies were claimed to have been hit by HE that passed through
clean w/o triggering. Thing is that may have been from dud rounds, AP, and the incendiaries
that only went off when emersed in liquid (I only know of 30mm incendiary shells that worked
that way.) but the evidence and pictures were clear of clean holes through wood. The strength
of the Mossie structure must be spread out wide as each piece of wood is only so strong.

You get the wood structure Russian planes doing poorly in such dives and pullouts too.
And those are deltawood.

faustnik
05-04-2006, 01:30 PM
Originally posted by p1ngu666:
mossie
370mph it starts shaking

740kph it falls to bits

http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

p1ngu666
05-04-2006, 02:21 PM
the mossie is mostly a sandwhich construction. 2 bits of ply with balsa in the middle for the fusealarge skining. offhand i cant remmber the wing structure, plywood skining, with fabric over the lot. high speed was the natural habitat of the mossie, infact the PR types would outdive attackers sometimes to get away, including 262's http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

the russians wanted to bulid mossies, but the types of wood needed wasnt there, and there wasnt time for a complete redesign.

i would guesstimate we have postwar dive limit as the divespeed. we have postwar ammo count, thats why theres so little ammo in the thing...

HelSqnProtos
05-04-2006, 03:55 PM
Originally posted by faustnik:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by p1ngu666:
mossie
370mph it starts shaking

740kph it falls to bits

http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif </div></BLOCKQUOTE>

So much for the beta test team putting the birds through their paces. If it is not a fw190 or bf109 forget about it.......

p1ngu666
05-04-2006, 07:09 PM
yep..

370mph is only a smidge above 366mph, they often did that speed at low level on ops.

pilot requires "pace notes" to guide them onto targets at low level, came up so fast http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

WWMaxGunz
05-04-2006, 09:57 PM
370mph Mossie starts shaking. Not falling apart.
740kph is over 450mph.

Mossie should dive faster then who does not know the drill, what Oleg demands for change?

Impressions I always got about fast bombers is that by the time interceptors could get up
and into the area, the bombers would be too far away to catch. This is partly born out by
the numbers of times when they did get caught by fighters already up and did take losses.
Unless someone will tell me that no Mossies were shot down by fighters?

What was it about 262's used for bombing and Arados I'd keep hearing? Oh yeah, making the
jets into bombers slowed them down enough for fighters to catch them, but those old shows
did not say often or not just someone looking at raw speed numbers saw it could happen.

Who knows construction of Pe-2's? I've waited long for this, another Russian plane rarely
covered and then only with doubtful data. Trim by electric switches in 194-what? Pretty
good. I would like to know more!

stathem
05-05-2006, 05:11 AM
Mossie pulls important bits off at 410-420mph IAS. By the time it disintegrates at 450 you're already a lawn dart. One of the contributing factors is it does have good dive acceleration, so you get to 400 mph quick when starting from 300.

Mossie NFs (not just XXXs) were extensively used on Anti-diver patrols, and very successfully (more kills than Spitfires, iirc), but they had the nose cones replaced with strengthened ones after the first few (original radar nose cones collapsed on a few, not terminal to the a/c though.) Oh yes, 150 octane and bucketfuls of overboost. Not sure if FB VI's were used.

I think P1ngu is right. The post-war pilot notes list Vne as 400 mph, but then the post-war notes but a much lower limit on lots of stuff like overload and aerobatics.

WWMaxGunz
05-05-2006, 07:14 AM
Postwar wood plane should have lower VNE due to age alone, no?

Perhaps that is where Oleg got the data for breakup. Now it will take a better source to
get hope of a change, won't it?

p1ngu666
05-05-2006, 08:22 AM
and ammo count aswell..

postwar mossies seem tobe much more limited, i think they also had 2 cannons removed.

very conservative

ImpStarDuece
05-05-2006, 09:06 AM
I know this isn't official, but the RAAF No 211 website lists the Vne of the FB MK VI as 425 mph without external stores and 400 mph with RPs fitted.

WWMaxGunz
05-07-2006, 01:05 PM
I finally got it set and working on my W98 machine with all the steps and yes I paid first
by what turned out to be two days but anyway it works with my old config (I backed everything
up, only a few gig) but there is some difference in the feel, call me silly....

I took Pe-2 and then Pe-3bis up for scoot-around and strafed some ships to see the guns.
I find that past 440kph the Pe-3bis is reluctant to turn or roll. My stick yaw is set
from 44 to 100 in steps of +4 all the way, not weak at the center and worked nice for me
ruddering my aim in the P-51C but Pe-3bis it took more and yawed slower though still usable
with enough lead distance. I made my main heading changes at the tops of zooms that lasted
until I was down to 320-340 with some turn in the beginning of the next dive.
How-dy does that plane pick up speed quick from 350 to 500kph in a shallow dive at even
only 60% power if the pitch is cut 85% or less. I noticed the reduced ability to turn at
450+ and I'd see the speed shoot right up and past that just doing tilted ellipses to hit
the ships, the top well under 1km alt maybe 500-600 to 800m and it turns into a lead sled.

Is this what you all see? Slow to turn at 450kph, how hard at 800kph? Use trim, right?

I look external view and the tails reminds my of something. They look a bit like the split
tail of some Beechcrafts, faster/slicker than the straight tail models.

DuxCorvan
05-07-2006, 03:39 PM
Ju 88 was designed as twin-engined stuka dive bomber...

Sergio_101
05-07-2006, 04:44 PM
Pe-2 out dives a P-51?

No kidding, it's Russian.

This is a Russian sim.

Sergio

Kwiatos
05-08-2006, 12:36 PM
It seemed that (beta)testers dont see any problem here. FM, DM and their elements are not so important in these game like new water, objects, and not nessesery planes. I dont know how such basic elements of FM like maximum speed, climb rate, maximum dive speed are not care in these game. I know that these is new plane in game but such simple thing like maximum dive speed are easy to check and correct but as ususally it is not checked and corrected in betatest.

WWMaxGunz
05-08-2006, 04:37 PM
So when did the P-51's stop being able to dive to and pull out at 950kph?
Just how maneuverable is the Pe-2 at 700kph let alone 900?

What a bunch of.............

Buzzsaw-
05-08-2006, 07:38 PM
Originally posted by WWMaxGunz:
So when did the P-51's stop being able to dive to and pull out at 950kph?
Just how maneuverable is the Pe-2 at 700kph let alone 900?

What a bunch of.............

Please provide track showing P-51 diving to 950 kph and pulling out successfully.

In tests in the past, 100% fuel, the P-51 instantly loses its wings in pullouts at that speed.

Only the 109K4 can dive to those speeds and pullout successfully. Which is of course complete nonsense considering its historical restrictions.

Now the PE-2 can do it???

WWMaxGunz
05-09-2006, 06:33 AM
Nope, I tried and I can't any more. Probably haven't dived P-51 to destruction since 3.x.
At or just after 900 kph the plane would lose pieces and soon no control, it is weaker even
without trying to pull up at all. Perhaps if I flew it better I could get more speed.
Pullout at 840kph was the best I could do in a quick look-see.

Pe-2 does handle at those speeds without controls locking. Slow but not dreadfully. The
P-51 has more response but then it is not a twin engine bomber either.

I flew the Oki map start at 7500 meters with different P-51's and Pe's. Aim for the island
just ahead and the concrete airfield as a target. Had to work hard to get even the best
Pe-2 to hit 810-820 by the time I crossed the field low and good pullout. P-51's reached
810kph loooooong before reaching the island. I pulled out at 830 IAS, climbed till speed
was below 400kph then rolled and dove again and still reached over 800 higher above the
field than the Pe did in a single straight and careful dive. But then I did no shifting
of superchargers (does Pe-2 have 2-stage?) and no mixture adjust so maybe I should go back
and find out.

Which out-dives which? Unless I blew it on engine management the P-51 leaves the Pe-2 in
the dust on acceleration at least in about 20-30 degree dive. But then I probably blew it
on engine management and maybe Pe-2 is very poor at 7.5km alt.

For sure I am not about to pull any P-51 out at 950kph or even 900kph no matter how slow
I pull the stick. It came apart at 900 without pullout though again, perhaps if I could
have kept the nose steadier I mighta gotten a bit more speed. Not the same old Mustang.

Pe-2 is not a wooden wonder such as some Russian fighters but I do have to wonder about
stick forces. Perhaps it was so slow to maneuver at 450+ for me because it is just slow
anyway. Perhaps the leverage of the linkages is set for highspeed pullout as it *is* a
divebomber. Also the construction, I bet it's heavy and strong. So if the flying is
optimistic then is it excessively so? We find out maybe, patch is due out for other
reasons already.

p1ngu666
05-09-2006, 12:27 PM
pe2 has fuel mix and supercharger stages. curiously u cant feather the props tho http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

ICDP
05-09-2006, 02:38 PM
Is it really that hard to test before we post? The P51D in this sim was never able to reach 950kph in a dive. It breaks up at 920kph and depending on dive angle you had better be pulling up long before then. The Bf109K4 is most definately NOT able to pull out of a dive at 950kph, it can't even get over 890kph before falling apart. As for the Pe2 it can reach 920kph in a dive but it takes a long time to get there and WILL NOT out accelerate a contempory fighter in the process.

Here are some dive figures. I used the method described by MaxGunz: Okinawa map, dive at full power using correct supercharger stages/mixture where applicable. Dive was from 7500m and I pointed straight at the concrete airfield on the island. This resulted in a dive angle of around 35-40 degrees.

The following aircraft all suffered structural damage at the speeds noted.
P51D: 920kph (572mph) The P51D had a 1G dive limit of 500mph <span class="ev_code_RED">*</span>
Bf109K4: 890kph
Spitfire MkIX (25lb): 840kph
Tempest V: 920kph
Fw190A8: 890kph
Fw190D9: 920kph
P38L: 920kph (572mph) The P38L had a 1G dive limit of 440mph IAS <span class="ev_code_RED">*</span>
F4U-1D: 840kph (521mph) The F4U-1D had a 1G dive limit of 443mph IAS <span class="ev_code_RED">*</span>

The following aircraft did not break up during the test. They either reached a maximum speed or were running out of altitude in the case of the P47D.

P47D-27: 980kph (609mph) The P47 had a 1G dive limit of 500mph IAS <span class="ev_code_RED">*</span>
Pe2: 850kph max speed in 35 degree dive.
SBD-5: 640kph max speed in 35 degree dive.
Ju87: 660kph max speed in 35 degree dive.
D3A1 Val: 560kph max speed in 35 degree dive.
Ju88A4: 770kph max speed in 35 degree dive.

<span class="ev_code_RED">*</span> The numbers for dive limits on the US aircraft are from AHT, they are obviously max recommended dive limits and should be seen as being conservative. I am only using them to show how much faster we can get these aircraft to dive in the sim. I don't have the equivelant numbers for the other aircraft.

For me the P47 has a great max dive speed but it doesn't seem to accelerate any faster than most of the other fighters until higher speeds. The P47, P51, Tempest V and Fw190D9 seem to have the best overall dive acceleration with the P47 having a poorer initial dive acceleration. All of these mentioned fighters easily outdive the other fighters in this dive test. The initial dive speed of the P47 was not as good as other US fighters according to data in America's hundred thousand where it ranked fourth after the P38G, P-51D and F4U-1D. Having said that I feel the P47 needs a minor dive acceleration boost or the others need toned down. I do not expect to leave other fighters in the dust during a dive from 2000m in a P47, P51, Fw190 or Tempest V. This is just not enough altitude to start to gain an advantage, even from 3000m is cutting it fine.

There are some minor dive acceleration issues IMHO but overall things are shaping up quite well. Just put these numbers into perspective.

980kph is 609mph IAS
920kph is 572mph IAS
890kph is 553mph IAS
840kph is 521mph IAS

Remember that at 920kph the P51 is 72mph over its posted 1G dive limit of 500mph according to AHT (505mph in the P51D cockpit wall). If you fly this much faster than the posted dive limits then don't be surprised if things start falling off. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Granted these fighters were sometimes tested to higher dive speeds but due to limitations of the sim there has to be some kind of limit impossed.

EDIT: I just tested the P51D and Fw190D9 in a dive from 10,000m (32,808ft) and I managed to reach a speed of 590mph IAS at 13,819 just before structural damage occuring. That is a TAS of 1201kph (746mph) or around mach 1.03! So it seems we can break the sound barrier just before our planes break up! Oleg I want a sonic boom http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Yes there are problems with the dive modelling in this sim but overall we can't complain given the sims original origins (IL2 only) and limitations. If it was easy to fix it would have been done by now IMHO. It isn't so far out that it makes the sim unplayable.

WWMaxGunz
05-09-2006, 10:29 PM
I'm pretty sure that at some point the P-51 could pass 950kph in a dive as I did run tests
and devicelinked the results. It was also more stable at high speed then. Now the nose
likes to wander a bit.

I find that lowering prop pitch really helps gain speed in about every CSP plane from about
400kph IAS on and makes a huge difference in dives. But go fast enough and the prop on all
becomes as a solid disk in reality, they all get the drag. On the big dia prop planes like
Corsair it has to be more, I wonder how prop lengths differed? When the prop is a major
source of drag then the heavies should get the clear margin.

Dude, I don't test every plane for every move for every patch or release but at least I ASK
when I post with IIRC and like. Was your mach speed dive IAS from guage or speedbar? IRL
the guage should read high and just may be simulated, I dunno about speedbar. How do you
test that?

ICDP
05-10-2006, 12:53 AM
The speed of 1201kph was taken from no cockpit view. This is the view all top speeds are taken from in the game. The P51 can reach 950kph IAS in a straight down dive before breaking up, as can the Fw190D9 or P38L. The normal break up speed is 920kph on these fighters so somehow there is a slight but worthless difference between vertical dives and normal dives. Sorry Max I wasn't getting at you, I was just correcting yours and Buzzsaw's comments. I would love to see Buzzsaw post a trak of him pulling out of a 950kph dive in a Bf109K4 though, especially with no wings http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

My main point was that we are already getting way over the max posted dive limit on most of these fighters. IMHO there is nothing to complain about if you are pushing your fighter anything up to 70-100+ mph over your fighters posted dive speed.

WTE_Galway
05-10-2006, 01:05 AM
Originally posted by WWMaxGunz:
I'm pretty sure that at some point the P-51 could pass 950kph in a dive as I did run tests
and devicelinked the results. It was also more stable at high speed then. Now the nose
likes to wander a bit.

I find that lowering prop pitch really helps gain speed in about every CSP plane from about
400kph IAS on and makes a huge difference in dives. But go fast enough and the prop on all
becomes as a solid disk in reality, they all get the drag. On the big dia prop planes like
Corsair it has to be more, I wonder how prop lengths differed? When the prop is a major
source of drag then the heavies should get the clear margin.

Dude, I don't test every plane for every move for every patch or release but at least I ASK
when I post with IIRC and like. Was your mach speed dive IAS from guage or speedbar? IRL
the guage should read high and just may be simulated, I dunno about speedbar. How do you
test that?


The problem with big props vs small props when transonic is not really drag its too do with supersonic shock waves. We are really getting into advanced aerodynamics here but this link gives some idea ..

http://www.aerospaceweb.org/question/aerodynamics/q0031b.shtml

mynameisroland
05-10-2006, 08:11 AM
Originally posted by ICDP:
The speed of 1201kph was taken from no cockpit view. This is the view all top speeds are taken from in the game. The P51 can reach 950kph IAS in a straight down dive before breaking up, as can the Fw190D9 or P38L. The normal break up speed is 920kph on these fighters so somehow there is a slight but worthless difference between vertical dives and normal dives. Sorry Max I wasn't getting at you, I was just correcting yours and Buzzsaw's comments. I would love to see Buzzsaw post a trak of him pulling out of a 950kph dive in a Bf109K4 though, especially with no wings http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

My main point was that we are already getting way over the max posted dive limit on most of these fighters. IMHO there is nothing to complain about if you are pushing your fighter anything up to 70-100+ mph over your fighters posted dive speed.

Three patches ago I took the Dora9 44 to over 1150 km/h in a dive and recovered with no control loss. This was not under test conditions but in an actual attack online.

WWMaxGunz
05-10-2006, 08:30 AM
Originally posted by WTE_Galway:

The problem with big props vs small props when transonic is not really drag its too do with supersonic shock waves. We are really getting into advanced aerodynamics here but this link gives some idea ..

http://www.aerospaceweb.org/question/aerodynamics/q0031b.shtml

A good read and news to me that such a prop was ever made let alone in the 40's.
Gotta love the destructive force of the shockwaves, that's how HE works. Get a couple waves
to interfere with each other, even the same wave reflected and the destruction multiplies.

Yeah the air going around the airframe moves faster than the frame itself as well so mach 1
for the plane is fierce on the plane. And those shockwaves also make for super drag.

I thought it would be about prop tips going supersonic, a turning prop has to move faster
than the plane as well which is another reason why to reduce rpm.

Now I can see that a small tweak may happen in a future patch. Perhaps something as small
as under 1/2 percent somewhere in drag or strength or modelled compression effect would be
enough to end dives over .96 or .98 mach. Or at least I can hope for such a tweak and it
not messing up some other thing(s).

Sergio_101
05-10-2006, 03:15 PM
Excellent article.
And the truth is that no prop plane
that saw service could get near mach-1
even in a dive.

As the data shows, the drag in the trans sonic
area is huge, and drops after exceeding Mach-1.

Chief problem in a plane designed to deal
with the extremely violent shock waves is noise.
Drag is an issue since your supersonic prop
will operate in the trans sonic flight
regime most of the time.

On the other hand people, jet aircraft operate
above Mach-1.
Note the compressor and turbine blades
are little more than propellers themselves.

The trick is to slow the inlet air speed
to a sub sonic speed before it reaches
the fan or compressor.

The future of supersonic props may well be
in a ducted fan with variable pitch format.

Sergio

BigKahuna_GS
05-10-2006, 07:02 PM
S!

__________________________________________________ ____________________________________________
ICDP
The following aircraft all suffered structural damage at the speeds noted.
P51D: 920kph (572mph) The P51D had a 1G dive limit of 500mph *
Bf109K4: 890kph
Spitfire MkIX (25lb): 840kph
Tempest V: 920kph
Fw190A8: 890kph
Fw190D9: 920kph
P38L: 920kph (572mph) The P38L had a 1G dive limit of 440mph IAS *
F4U-1D: 840kph (521mph) The F4U-1D had a 1G dive limit of 443mph IAS *

The following aircraft did not break up during the test. They either reached a maximum speed or were running out of altitude in the case of the P47D.

P47D-27: 980kph (609mph) The P47 had a 1G dive limit of 500mph IAS *
Pe2: 850kph max speed in 35 degree dive.
SBD-5: 640kph max speed in 35 degree dive.
Ju87: 660kph max speed in 35 degree dive.
D3A1 Val: 560kph max speed in 35 degree dive.
Ju88A4: 770kph max speed in 35 degree dive.
__________________________________________________ __________________________________________


Nice testing and post ICDP.
You are right about the dive limits on the US aircraft--they are very conservative and had more to with avoiding compressibility. The RAF dive tested the P51 and cleared it for emergency dives of .83 mach for combat. The P47 was also cleared for that speed.

The placard dive speed limits were generally set to keep a plane from going into compressibility, not to keep them from breaking up. Planes could fly faster, with compressibility effects. For instance, the P-51D Mustang could fly at up to mach .74 before going into compressibility. As it exceeded that speed, compressibility effects increased. At about mach .84 it began to suffer structural damage from all the vibration and buffetting.

P51 power diving from 25,000ft chasing a 109 already in a dive.
"-At 10,000 feet, I initiated a steady four-G pullout and the ME-109 started to pull out about the same time. But before he had raised his nose more then thirty degrees, his right wing ripped off through the wheel well and he spun into the ground in a matter of seconds. He had no time to get out and was still aboard when the 109 impacted and exploded in a wooded area. Just before I started my pull-out I glanced at the airspeed indicator and saw the needle on 600 miles an hour, ninety-five per hour over the red-line speed of 505."

*See: Astor Gerald. The Mighty Eighth p.365

This P51D pilot was going 600mph Indicated Air Speed, 95mph over the redline speed of 505mph IAS.

I also agree with you on the P47. It accelerates too slow throughout the whole dive until very high speed is reached--almost termianl speed.


__

WWMaxGunz
05-11-2006, 08:07 AM
Pitots and IAS guages of those times read high with increasing mach. They still do though
I read some are corrected in the guage there are still formulae used by jet pilots to get
the right numbers from mach .6 (only a % or so high) up. That is for real guages and planes.

ICDP
05-11-2006, 10:33 AM
Hi Kahuna,

IMHO the fighters in PF+FB+AEP are behaving fairly well now in relative dive speeds. There are one or two quirks such as the mach 1 dive speeds of some fighters and the fact that the P47 takes a tad too long to start showing ANY advantage. I used to believe icorrectly that if I got into bother all I had to do in the P47 was point down and I would instantly leave any plane in the dust.

I have come to realise that this is an unrealistic expectation. If I am co alt and speed with a Bf109 or Fw190 on my six it will take time to pull away. In the meantime I am inside gun range of my enemy. IMHO the P47 and P51 are better divers than the 109's and 190A's but the P47 should be slightly better than it is currently.

WWMaxGunz
05-11-2006, 08:33 PM
By the results of one British comparison between P-47 and FW-190 you should expect the
FW to catch up before you start to get any lead at all. 10,000ft to 3,000ft, the FW
was in the lead with P-47 only catching up at the bottom where it had greater speed
but just how much greater was not noted. That was start speed 400kph and no moving
the throttles of either plane. 7,000ft vertical in a 65 degree dive, about 8,000ft
travel though it doesn't take long in the sim.

ICDP
05-12-2006, 02:26 AM
Hi Max

I am aware of that report and it is one of the eye openers that caused me to rethink my expectations. Simply pointing the nose down is not enough when both fighters are co alt and speed. For example it is widely accepted that the F4F or P40 outdives the A6M2. This dos not mean an F4F or P40 pilot simply points his nose at the ground and leaves the A6M2 in the dust. He has to use his superior roll-rate to keep out of the A6M2's gunsight and eventually he will easily leave the A6M2 behind.

As far as I am concerned the dive modelling in this sim is quite good and does reflect history reasonably well. The initial post regarding the Pe2 has been suitably addressed IMHO. Yes the Pe2 can dive to slightly higher speeds than a 190 or 109 but it won't accelerate faster so it is still easy pickings in a dive. Just because it dives to higher speeds doesn't make it a better diver. The P47 is a perfect example of this http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Buzzsaw-
05-14-2006, 03:07 PM
Salute

Pointing the nose of an aircraft vertical, and then holding it in a dive till it disintegrates is a completely irrelevant test and determines nothing. If a pilot cannot recover his aircraft, then being able to dive to a particular speed is useless.

The only test that is relevant is one where the aircraft is dived to a particular speed, and then recovers successfully WITHOUT any damage.

Any number of aircraft in the game can dive to very high speeds, but they cannot recover. Listing their terminal as being the point at which they disintegrate is nonsense.

ICDP:

The Bubble top P-47D had a dive speed limit of 550 mph IAS, the Tempest a limit of 540 mph IAS.

ICDP
05-14-2006, 03:20 PM
Hi Buzzsaw,

If you read my first test you will find that I didn't dive vertical. The dive was made at a 35-40 degree angle and I could have easily pulled out before the planes broke up but that would have voided the test. The test was conducted to show that neither the P51 nor the Bf09K can dive to 950kph. The test was also to show that the Pe2 could not outdive a P51 and the fact that the Pe2 could reach only 850kph and took a long time getting there proved that it WILL NOT outdive the P51D. I do agree that diving until the plane breaks up is mostly irrelevant but for the purposses of this discussion it was relevant and necessary.

Thanks for posting the dive limit of the Tempest, is it safe to assume that this is a conservative number?

p1ngu666
05-14-2006, 07:05 PM
yeah i bet so.

p47 is a big round fat aircraft

typhoon is all aggression and butchness

tempest looks sleak, perposeful. just look like it will cut thru the luftwaffe like a movie hero thru extras http://forums.ubi.com/images/smilies/784.gif

even when painted as a target tug http://forums.ubi.com/images/smilies/disagree.gif

Buzzsaw-
05-14-2006, 08:34 PM
Salute

When it was tested by the RAF, the Tempest at +9 boost had the best dive acceleration of any aircraft examined up to that time, and that would include the P-47D Razorback, the 190A5, Mustang III and Spit XIV. The 190D9 had not yet been tested, nor the Bubble top P-47.

Buzzsaw-
05-14-2006, 08:39 PM
Originally posted by ICDP:
The dive was made at a 35-40 degree angle and I could have easily pulled out before the planes broke up...


Pulled out at what speed?

WWMaxGunz
05-14-2006, 09:14 PM
Originally posted by ICDP:
Hi Max

I am aware of that report and it is one of the eye openers that caused me to rethink my expectations. Simply pointing the nose down is not enough when both fighters are co alt and speed. For example it is widely accepted that the F4F or P40 outdives the A6M2. This dos not mean an F4F or P40 pilot simply points his nose at the ground and leaves the A6M2 in the dust. He has to use his superior roll-rate to keep out of the A6M2's gunsight and eventually he will easily leave the A6M2 behind.

I've read Eric Schilling and other AVG pilots who fought through the war and the picture I read
has them dive in for an attack pass then roll and dive. In the exit dive they keep rolling as
the Zero cannot match their roll to get a leading shot. And they did not let speed get down
below 240-250mph where the Zero would be able to roll onto them.

Speed margins and other margins between the best are not very wide in general as percentages
of total performance. Yet there are exploitable edges. A small difference in top speeds
will allow the faster plane to outclimb by more at higher end speeds than lower, it takes
more power to go X kph faster at high speed than the same X kph difference at middle speed.
10kph faster plane can go 5kph faster and still climb some while the other can lose by 5kph
or climb and lose by 10kph. If the climb is a big spiral then the follower does not get the
shot and stands to get jumped on eventually.

ICDP
05-15-2006, 04:10 AM
Originally posted by Buzzsaw-:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
The dive was made at a 35-40 degree angle and I could have easily pulled out before the planes broke up...


Pulled out at what speed? </div></BLOCKQUOTE>

That's a good question Buzzsaw. I will reconduct the test and take note of when the buffeting starts and the maximum safe pullout speed. I should also take a note of the time taken to reach the pullout speed and the altitude the pullout occured.

Bogun
05-17-2006, 08:43 AM
Originally posted by Buzzsaw-:
Please provide track showing P-51 diving to 950 kph and pulling out successfully.

In tests in the past, 100% fuel, the P-51 instantly loses its wings in pullouts at that speed.

Only the 109K4 can dive to those speeds and pullout successfully. Which is of course complete nonsense considering its historical restrictions...

We had a discussion on our squad forum about P-51 loosing wings in high-G pullouts (which it does) and to prove the point I recorded two tracks €" P-51 and Fw-190A-6 pulling out of 1040km/h TAS dive with no damage.
Did not test Bf-109K-4 but would not be surprise if it does that as well.

Sad, enough whining can persuade Oleg to allow such things.

WWMaxGunz
05-17-2006, 03:46 PM
On 4.04 or 4.05 you did this? P-51 loses parts for me just at or slightly over 900kph IAS
even at low alt. But then I am not able to keep the nose perfectly straight past about
840kph IAS, maybe that is why.

It *used to be* that P-51 highspeed was very stable and one of the best over 900kph.
P-47 was even more so stable. Late FW's were also stable up to destruct. Then we left the
3.x for a truer FM, another step now finished with 4.05 IMO.

BigKahuna_GS
05-17-2006, 09:31 PM
S!

__________________________________________________ _____________________________________________
MaxGuns---And they did not let speed get down
below 240-250mph where the Zero would be able to roll onto them.
__________________________________________________ _____________________________________________


Hya Max,

At 240-250mph the P40 had roughly triple the roll rate of the Zero. In order for the Zero to have a comprable roll rate to the P40 speeds would have to be around 150-180mph anything over this and control forces would start building up. Also from Koga's Zero, the US Navy found out it was very difficult for the Zero to roll right against engine torque. So the perferred method of escape was to nose down and roll right into a very fast sweeping right hand turn where it was nearly impossible for the Zeke to follow.


___

WWMaxGunz
05-17-2006, 09:45 PM
I'm only going by what Eric Schilling wrote. He flew P-40's even against Zeroes.
You know that going slow for a plane doesn't let you get out of the way quickly.
Roll rate is not the whole battle.

BigKahuna_GS
05-17-2006, 10:31 PM
S!

Rgr that Max. I have read Schilling and he used his superior roll rate and dive speed to effectively fight Zekes.

BigKahuna_GS
05-17-2006, 10:37 PM
S!

NACA Terminal Dive Speed for P38

http://history.nasa.gov/SP-4219/Chapter3.html

FROM ENGINEERING SCIENCE TO BIG SCIENCE 83

The general aeronautics community was suddenly awakened to the realities of the unknown flight regime in November 1941, when Lockheed test pilot Ralph Virden could not pull the new, high-performance P-38 out of a high-speed dive, and crashed. Virden was the first human fatality due to adverse compressibility effects, and the P-38, shown below, was the first airplane to Suffer from these effects. The P-38 exceeded its critical Mach number in an operational dive, and penetrated well into the regime of the compressibility burble at its terminal dive speed, as shown by the bar chart on page 80 .35 The problem encountered by Virden, and many other P-38 pilots at that time, was that beyond a certain speed in a dive, the elevator controls suddenly felt as if they were locked. And to make things worse, the tail suddenly produced more lift, pulling the P-38 into an even

http://history.nasa.gov/SP-4219/4219-083.jpg
Lockheed P-38, the first airplane to encounter severe compressibility problems.
35. This chart is taken from the figure on page 78 of the article by R. L. Foss, "From Propellers to Jets in Fighter Aircraft Design," in Jay D. Pinson, ed., Diamond Jubilee of Powered Flight: The Evolution of Aircrafeet Design (New York, NY: American Institute of Aeronautics and Astronautics, 1978), pp. 51-64.

http://history.nasa.gov/SP-4219/4219-084.jpg

http://history.nasa.gov/SP-4219/4219-084.jpg

Bar chart showing the magnitude of how much the P-38 penetrated the compressibility regime.

steeper dive. This was called the "tuck-under" problem. It is important to note that the NACA soon solved this problem, using its expertise in compressibility effects. Although Lockheed consulted various aerodynamicists, including Theodore Von Kármán at Caltech, it turned out that John Stack at NACA Langley, with his accumulated experience in compressibility effects, was the only one to properly diagnose the problem. The wing of the P-38 lost lift when it encountered the compressibility burble. As a result, the downwash angle of the flow behind the wing was reduced. This in turn increased the effective angle of attack of the flow encountered by the horizontal tail, increasing the lift on the tail, and pitching the P-38 to a progressively steepening dive totally beyond the control of the pilot. Stack's solution was to place a special flap under the wing, to be employed only when these compressibility effects were encountered. The flap was not a conventional dive flap intended to reduce the speed. Rather, Stack's idea was to use the flap to maintain lift in the face of the compressibility burble, hence eliminating the change in the downwash angle, and therefore allowing the horizontal tail to function properly. This is a graphic example of how, in the early days of high-speed flight, the NACA compressibility research was found to be vital as real airplanes began to sneak up on Mach one.36

Indeed, it was time for real airplanes to be used to probe the mysteries of the unknown transonic gap. It was time for the high-speed research airplane to become a reality. The earliest concrete proposal along these lines was made by Ezra Kotcher, a senior instructor at the Army Air Corps Engineering School at Wright Field (a forerunner of today's Air Force Institute of Technology). Kotcher was a 1928 graduate of the University of California,



--------------------------------------------------------------------------------

36. The "tuck-under" problem, and its technical Solution, is described in John D. Anderson, Jr., Introduction to Flight (New York, NY. McGraw-Hill Book Co., 3rd ed., 1989), pp. 406-08.


According to the chart it looks like the terminal dive speed of structeral failure was well beyond .80 mach for the P38. Probably .85 mach.


_

BigKahuna_GS
05-17-2006, 10:38 PM
S!


http://history.nasa.gov/SP-4219/4219-084.jpg