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View Full Version : Brief test of Zoom Climb abilities, V1.1b



XyZspineZyX
08-20-2003, 01:27 PM
I spent a few minutes for gathering some factual data of the in-game zoom climb performance under controlled conditions:

-Crimea map
-Start of zoom: 110%+all boosts, 50m altitude, 500kph TAS.
-All planes Default armament, 100% fuel
-Closed radiators

The zoom climb itself was made at apprx. the same angle, using the Cocpit off view mode, and the artificial horizont there. The planes were pulled up gently until the "Ground" sink below edge of the A.H. Then they were kept horizontal, and were corrected to keep angle at the upper end of the zoom. The maximum altitude reached was recorded.

It should be noted that this record was greatly effected by stall characteristics (D-9, P-47).

A

Results:

109K-4: 1400m
109G-2: 1400m
109G-6: 1250m (early G-6)
190D-9: 1320m (1945 variant)
P-47D-27: 1200m
La-7 : 1540m (3xB-20 variants. It seems Soviet planes don`t bleed E, don`t stall /i/smilies/16x16_smiley-wink.gif )
Yak-3: 1330m


http://vo101isegrim.piranho.com/FB-desktopweb.jpg
'Only a dead Indianer is a good Indianer!'

Vezérünk a Bátorság, K*sérµnk a Szerencse!
(Courage leads, Luck escorts us! - Historical motto of the 101st Puma Fighter Regiment)

Flight tests and other aviation performance data: http://www.pbase.com/isegrim

XyZspineZyX
08-20-2003, 01:27 PM
I spent a few minutes for gathering some factual data of the in-game zoom climb performance under controlled conditions:

-Crimea map
-Start of zoom: 110%+all boosts, 50m altitude, 500kph TAS.
-All planes Default armament, 100% fuel
-Closed radiators

The zoom climb itself was made at apprx. the same angle, using the Cocpit off view mode, and the artificial horizont there. The planes were pulled up gently until the "Ground" sink below edge of the A.H. Then they were kept horizontal, and were corrected to keep angle at the upper end of the zoom. The maximum altitude reached was recorded.

It should be noted that this record was greatly effected by stall characteristics (D-9, P-47).

A

Results:

109K-4: 1400m
109G-2: 1400m
109G-6: 1250m (early G-6)
190D-9: 1320m (1945 variant)
P-47D-27: 1200m
La-7 : 1540m (3xB-20 variants. It seems Soviet planes don`t bleed E, don`t stall /i/smilies/16x16_smiley-wink.gif )
Yak-3: 1330m


http://vo101isegrim.piranho.com/FB-desktopweb.jpg
'Only a dead Indianer is a good Indianer!'

Vezérünk a Bátorság, K*sérµnk a Szerencse!
(Courage leads, Luck escorts us! - Historical motto of the 101st Puma Fighter Regiment)

Flight tests and other aviation performance data: http://www.pbase.com/isegrim

XyZspineZyX
08-20-2003, 01:35 PM
I find that f**ked up and this verifies my own experience flying the 109 vs. LA's and Yak's. I thought 109 and 190 were supposed to have superior dive/climb abilities. I always knew something was not right with these VVS planes catching me when I play a flawless game of B&Z. Pretty much means that the minute you get CO-E or worse you have no options to gain E vs. a good pilot and bring him down. You'll end up running until you're dead.

XyZspineZyX
08-20-2003, 01:42 PM
Here are some numbers for vertical zoom climb.

Basically, mission starts with airplane pointed straight up at 600km/h. 100% power is applied. Starting at 1000m.

note: engine spoolup time may vary, so it may have small effect on results. Engine spool up is much faster than 1.0, and seems to mostly uniform among late war planes.

Alt gained in zoom

Bf-109K4: 1630m
Yak-3: 1650m
La-7: 1730m
P-47D27: 1540m
FW-190D9: 1550m
Me-2621A: 1700m

Results are not suprising. The best zoomers have either high T/W (yak-3) or low drag (me-262). The La-7 has a combination of both.

Although I constantly read of how good FW and P-47 are supposed to be in zoom, I can't find a way to mathematically prove it. B/c logically the only factors in a vertical zoom are starting speed, T/W and drag.

The drag/inertia ratio is lower on a heavier plane, sure, and that would allow the heavier plane to "hold energy" against the force of drag, but that would only make a difference at very high speeds (also heavy planes are usually bigger=more drag). In a zoom most of your time is spent at low speed, using the force of your engine to helicopter you against your weight.



Message Edited on 08/20/0307:29AM by StG77_Fennec

XyZspineZyX
08-20-2003, 04:09 PM
Actually the d9 will out -zoom the soviets, it just has to be done at higher speeds,after a dive.The La can't go fast enough to improve its zoom by much.The yak can but the d9 still wins.

XyZspineZyX
08-20-2003, 04:22 PM
Well, I can tell you that my dora was consisitently caught by p39's in methanol boosted zoom climbs even when i had altitude(slight, 100-200 Meter) advantage. This did not seem right to me...is it right?? They still dont catch me in my 262 though...

"I am a hunter. When I have shot down an Englishman my hunter's passion is satisfied for a quater of an hour."
-Manfred Von Richtoffen

" I fear no over heat 'till the needle on both guages hits the nine...Then it's too late."
-Me


Me to the Smithsonian; "Wanna sell your 190D??"

XyZspineZyX
08-20-2003, 04:34 PM
Zoom climb is a nono in the D9, always was. That's how I used to get shot down the most.

Nic

XyZspineZyX
08-20-2003, 04:47 PM
"I find that f**ked up and this verifies my own experience flying the 109 vs. LA's and Yak's. I thought 109 and 190 were supposed to have superior dive/climb abilities."

Compared to heavy US iron, or early VVS fighters, maybe. Against late war Yaks and Las? I wouldn't bet on it.

Besides, tests on zoom climbs are very delicate, as finding the exact boundary between a "zoom climb" and a "climb" is not really that simple.

For instance, in theory, if a P-47 and a Bf109 would both start a zoom climb of 45 degrees, the initial superiority in zoom climb would go to the P-47 - heavy mass in motion is hard to stop. But as both planes near their best climb speeds, the "climb rate" factor will take over the "zoom climb" factor, and ultimately, the Bf109 will be able to reach a higher altitude before stalling out.

Thus, given the many various situation of combat, an attempt to out-zoom an enemy plane behind you in a vertical move, inevitably needs very price judgement in relative E-states - something, not everyone is capable of.

When I see someone complain about being followed by an enemy behind them when they go into vertical, nine times out of ten there was a mistake on part of the pilot. There are so many more factors to consider the relative distance between planes, relative speed between planes, difference in maneuverability, possibility of the enemy "leading the zoom", differences in armament, differences in flight characteristics, how the enemy managed his E comapred to yours.. and etc etc.

..

I suggest that the data on the differing time of when the compared planes may reach a certain same altitude, must also be recorded - ie. if a P-47 and a Bf109 is compared, how fast each one of them will reach a 200 meter point, a 500 meter point, a 1000 meter point and etc.

If the Fw190s and the P-47Ds cannot reach a certain set zoom distance faster than the lighter planes such as Yaks or 109s, then there's a bit of problem.






-----------
Due to pressure from the moderators, the sig returns to..

"It's the machine, not the man." - Materialist, and proud of it!

XyZspineZyX
08-20-2003, 04:50 PM
kweassa wrote:
- For instance, in theory, if a P-47 and a Bf109
- would both start a zoom climb of 45 degrees, the
- initial superiority in zoom climb would go to the
- P-47 - heavy mass in motion is hard to stop. But as
- both planes near their best climb speeds, the "climb
- rate" factor will take over the "zoom climb" factor,
- and ultimately, the Bf109 will be able to reach a
- higher altitude before stalling out.


What do you mean by "heavy mass in motion is hard to stop" in a zoom climb?? The weight of the airplane drags it down not up, what's this nonsense kweassa?


<center> http://www.stormbirds.com/images/discussion-main.jpg </center>

Message Edited on 08/20/0310:54AM by Huckebein_FW

XyZspineZyX
08-20-2003, 05:19 PM
Another Brief test of zoom climb abilities after dive.
I noticed this too while testing the d9 45. After a high speed dive(900 kmh TAS several alt levels 3k 4k 5k 6k) and zoomclimb ( 90 degrees) a k4 p39 p47 can catch up.

For the p47 i think its historical that it can catch up in dive. For the K4 the acceleration in dive is behind that of the fw and when we compare the E state at same alt that of the FW is higher at same speed and alt duo its weight.(Simpliefied) E= mgh + 1/2 mv^2. Takeoff Weight K4 3362 KG D9 45 4350 kg (Il2fb database)

Some test with d9 45 100 % fuel
110% MW50 radiator closed . Autopitch Dive 90 degrees after rollover. Pullup at 900 kmh tas near blackout. Then zoomclimb 90 degrees until plane isnt able to climb anymore .

Estart = 4350 kg * 9.81 m/s^2 * 5036 m + 1/2 *4350 kg* 597 km/h ^2
= 214903746 kg m^2 / s^2 + 59814010 m^2 / s^2
= 274717756 kg m^2 / s^2

Dive pullup at 900 kmh
Eend = 4350 kg * 9.81 m/s^2 * 5057 + 1/2 4350 kg * 196 km/h ^2

Eend = 222247019 kg m^2 / s^2 .

So E loss after dive with closed radiator 20 % on D9 45 from 5k at that speed of 597 kmh.

Now same for k4

Estart = 3362 kg * 9,81 m/s^2 * 5036 m + 1/2 * 3362 kg * 592 kmh ^2

Estart = 166093423 kg * m^2 / s^2 + 45457560 kg * m^2 / s^2
Estart = 211550983 kg * m^2 / s^2

Eend = 3362 kg * 9.81 m/s^2 * 5200 m + 1/2 * 3362 kg * 86 kmh ^2
Eend = 171502344 kg m^2 / s^2 + 959311 kg m^2 / s^2.

Eend = 172461655 kg m^2/s^2

E loss on k4 at 592 kmh at that alt with closed radiator after dive and zoomclimb 19 %. So the E loss is almost identical on both.

Some dive tests from 5k at 250 ias closed radiator did show that the K4 reaches the 900 km/h mark around 2300 m and the d9 45 around 2400 m . Tests were done over open water several times so influences of alt changes from mountains are not in .

It seems K4 is the better E keeper but maybe has to do with the high speed rudder possibilites of the d9 where most likely the e bleed is max then and relative higher than that of the k4. Also the heavy weight of the d9 bleeds more Energie in zoomclimb than the K4. For the airfriction part the shape of the k4 seems (no cw values for k4) not as aerodynamic as that of the dora. (Airfriction values used in FB unknown).

Maybe someone has a dora and k4 dive and zoomclimb real life data chart.












Message Edited on 08/20/0304:21PM by BBB_Hyperion

XyZspineZyX
08-20-2003, 05:39 PM
Hyperion your calculation is not correct, airplane dives are powered they are not heavy objects thrown from a certain height.


<center> http://www.stormbirds.com/images/discussion-main.jpg </center>

XyZspineZyX
08-20-2003, 06:16 PM
Huckebein_FW wrote:
- Hyperion your calculation is not correct, airplane
- dives are powered they are not heavy objects thrown
- from a certain height.
-
-
- <center> <img
- src="http://www.stormbirds.com/images/discussion-m
- ain.jpg"> </center>

Agree as i pointed out it is "simpliefied" regardless to engine power /weight ratio. The Engine adds continuesly energie to the system in dive and in climb. Its only a rough "guess" about the E keeping and i didnt want to make it too complex . I think the engine power/weight ratio is pretty close in this case.

XyZspineZyX
08-20-2003, 06:17 PM
"What do you mean by "heavy mass in motion is hard to stop" in a zoom climb?? The weight of the airplane drags it down not up, what's this nonsense kweassa? "

Some nonsense that has to do with inertia?

-----------
Due to pressure from the moderators, the sig returns to..

"It's the machine, not the man." - Materialist, and proud of it!

XyZspineZyX
08-20-2003, 06:24 PM
I would like to see these same test done by someone who isn't biased to the German planes.

Just to make sure it's all accurate. I'm not saying the results are wrong. I'm just being careful before I form an opinion.

25th_Buzz
------------------------------------------------------------------------------------------------------------------------------------------------------------------
<center>
http://www.vfa25.com/sigs/buzz.jpg

XyZspineZyX
08-20-2003, 06:51 PM
The erroneous climbrate of the La-7 will give an un-realisticly high zoom climb. The Dora's climbrate is close to spot on except for the 44' Dora which is too high. According to other peoples reports the K-4 climbrate is pretty accurate. I don't know about the Yak-3 climbrate. I haven't tested it yet. It's climbrate should be close to the D-9.

http://www.iownjoo.com/freeimghost/robban75/Dora-9-3.JPG


'When it comes to aircombat, I'd rather be lucky than good any day!'

XyZspineZyX
08-20-2003, 07:08 PM
If the K4 climb rate is right. The G2 must be off then.

I wonder how Oleg does his tests to see if the FM's are accurate.

25th_Buzz
------------------------------------------------------------------------------------------------------------------------------------------------------------------
<center>
http://www.vfa25.com/sigs/buzz.jpg

XyZspineZyX
08-20-2003, 07:19 PM
kweassa wrote:
-
- "What do you mean by "heavy mass in motion is hard
- to stop" in a zoom climb?? The weight of the
- airplane drags it down not up, what's this nonsense
- kweassa? "
-
- Some nonsense that has to do with inertia?


Well, when identifying force components in physics, inertia is opposite to the acceleration of the specific object. Since the plane's acceleration would be vertical, pointing upwards, inertia would be pointing down, same as G force. (assuming the angle is 90 deg.; even if it isn't, it still has a vertical component which would be pointing down).

http://members.shaw.ca/cuski4678/sig.jpg


Message Edited on 08/20/0311:23AM by cuski

XyZspineZyX
08-20-2003, 08:40 PM
- Eend = 222247019 kg m^2 / s^2 .

- So E loss after dive with closed radiator 20 % on D9
- 45 from 5k at that speed of 597 kmh.

- Eend = 172461655 kg m^2/s^2

- E loss on k4 at 592 kmh at that alt with closed
- radiator after dive and zoomclimb 19 %. So the E
- loss is almost identical on both.
-
Some calculations regarding to Engine Power for Huckebein hopefully not that much typos.

Assuming Engines run at full power for the testime (What we know they dont but its the maximum energie that can be added to the system by engines (exhaust gases upspeeds aside))

FW190d9 2240 PS = 3044 kW running time 51 s (for dive & climb)
BF109K4 1800 PS = 2446 kW running time 49 s (for dive & climb)
BF109K4 2000 PS = 2717 kW "

Energiestates Engines after testime
d9=155244 kW
k4=119854 kW
k4=133133 kW

Comparing d9 engine to last E state D9.

% of endenergie = 155244 kW / 222247019 kg m^2 / s^2
= 0.6985 = 70 %

Comparing K4 engine to last E state K4

% of endenergie = 119854 kW / 172461655 kg m^2 / s^2
= 0.6949 = 70 %

% of endenergie = 133133 kW / 172461655 kg m^2 / s^2
= 0,7719 = 77 %

So when we add the last Energie Calculation to the endstate .
We see a energie value thats about

d9
% of change = 377491019 / 274517756 = +37,5 %

k4
% of change = 292315655 /211550983 = +38 %
% of change = 305594655 /211550983 = +44 %

So you can see engines dont really effect the outcome in this case the relative equal energie output in conjunction with the planeweight of both engines makes it possible. The 37 and 38 % are pretty close dont know which engine is modeled for the K4 so i added the more ps one too (that would show a significant difference in performance).

As this are all relative figures it still comes out that the k4 is the better e keeper . (When for example you add fuel store to the energie formula you can bring the numbers in the
the other way but it dont effects the relative values to each other).

XyZspineZyX
08-20-2003, 09:45 PM
From dive to zoom from the deck at near max speed of D9,P-39,Yak3,La7and Yak9u,the d9 wins easily except for Yak3,which is only beat by about 100-200m.
The d9 was capable of pulling a zoom to roughly 2400-2500m,this was with everything auto and 50% fuel.

XyZspineZyX
08-20-2003, 10:48 PM
I just did a quick diving test with the D-9´45, La-7 and P-47. I started in QMB at 3000m. I waited for the engines to spool up and a speed of 400km/h was reached before I rolled inverted and gently turned towards the ground. i marked speed at 1500m. It seemed as though dive accelerations are quite similar from one plane to another. The La-7 had the best dive acceleration, and it was slightly superior to the D-9. The P-47 was the slowest of the three and quite inferior to the La-7. However prolonged dives is impossible with La-7 as it will come appart. This was not a serious test but I dove the D-9 and La-7 several times and the La-7 always reached a higher speed at 1500m. Perhaps the La-7 had a good dive acceleration I don't know.

http://www.iownjoo.com/freeimghost/robban75/Dora-9-3.JPG


'When it comes to aircombat, I'd rather be lucky than good any day!'

XyZspineZyX
08-21-2003, 01:24 AM
Vo101_Isegrim, could you perform those exact same tests, but start test altitude at maybe 6km instead? Especially 109K-4 and La~7 if you don't have time for all the others. Thanks.



robban75 reports::
- The La-7 had the best dive acceleration, and it was
- slightly superior to the D-9. The P-47 was the slowest of
- the three and quite inferior to the La-7. However
- prolonged dives is impossible with La-7 as it will come
- apart. This was not a serious test but I dove the D-9
- and La-7 several times and the La-7 always reached a
- higher speed at 1500m.

Dive angles, initial speeds, final speeds, etc... La just may out accelerate the others at low level dive until it nears its max dive speed, and that may be the trick. Try diving farther than 1500m to see what happens eventually (if you must go up to 5km or so, then consider it).

XyZspineZyX
08-21-2003, 03:34 AM
this thread is all fine and dandy but when you get to real LIFE pilot accounts german and american the p47 out zoomed every freekin german plane hands down and without effort. so all those tables and graphs are fine and your theories are fantabulous but theres only one small hole in the equation. REAL LIFE PILOTS found the jug to out zoom everyone and everything everytime in every book german and american both....hmm....they must all be wrong .

www.fighterjocks.net (http://www.fighterjocks.net) home of the 11 time Champions Team AFJ. 6 Years Flying http://www.world-data-systems.com/aerofiles/albums/userpics/p47-22.jpg 47|FC=

XyZspineZyX
08-21-2003, 06:34 AM
The problem is they never define the term "out zoom".

Even USA pilots said that initial dive acceleration in P-47 was poor, for example, vs Spitfire. Only at higher speeds (ie. nearing vmax) did it pull away.

http://www.smiliedb.de/s/sdb06894.gif http://www.smiliedb.de/s/sdb57471.gif http://www.smiliedb.de/s/sdb11726.gif http://www.smiliedb.de/s/sdb75733.gif http://www.smiliedb.de/s/sdb80477.gif http://www.smiliedb.de/s/sdb64472.gif http://www.smiliedb.de/s/sdb59442.gif http://www.smiliedb.de/s/sdb80347.gif http://www.smiliedb.de/s/sdb73057.gif http://www.smiliedb.de/s/sdb48642.gif

XyZspineZyX
08-21-2003, 06:51 AM
BuzzU wrote:
- I would like to see these same test done by someone
- who isn't biased to the German planes.
-
Would you form an opinion when for example skychimp does an USAAF-biased test? Would that be better place to form a "neutral opinion"? /i/smilies/16x16_smiley-happy.gif

Funny.

XyZspineZyX
08-21-2003, 11:05 AM
Kannaksen_hanu wrote:
- Would you form an opinion when for example skychimp
- does an USAAF-biased test? Would that be better
- place to form a "neutral opinion"? <
- Funny.
-
Good Idea !! How about another test Skychimp.


"We make war that we may live in peace."

Aristotle

XyZspineZyX
08-21-2003, 11:36 AM
Guys to really be able to determine if one type of plane can out dive/out zoom climb another, we need proper data about the relative performances of the planes and someone who really knows what they're talking about.

If the chief aerodynamicist at Airbus appeared in this thread with their conclusions on this subject, I would definitely listen to what they had to say.

A lot of the posts so far just seem to be fairly speculative as far as I can see.

We could argue and discuss this subject until the cows come home, but without actual data and the input of an experienced aerodynamicist, no conclusions of any value are going to be reached.

Sorry to be so negative.

XyZspineZyX
08-21-2003, 12:26 PM
Its easy to determine the dive and zoom capabilities of the various aircraft in the game.And to make comparisons.We don't need "proper" data from outside the game except to determine how close to reality the planes performed.Which is useful,but won't help in the game at this time.

XyZspineZyX
08-21-2003, 01:06 PM
The P-47 can actually zoom 3250m but it needs 4800-4900m to be able to build up the speed neccesary to do so.

XyZspineZyX
08-21-2003, 02:34 PM
The test conditions strike me as rather pointless. 50m is way too low and 500kph is way too slow.

people who test dive acceleration need to do unloaded dives (very hard without a G-meter).

I may get around to doing tests under conditions that I would expect to show some differentiation between the planes' performances.

How about this procedure:

a) start from way high altitude and dive so that you are maintaining a constant high speed (say 800kph TAS)

b) when you reach a certain altitude (say 4000m) pull up gently into whatever angle you want to test (I prefer lower angles then most people seem to want to use).

b) stop the test when a certain speed is reached (say 400kph TAS, or maybe 500, 400 is kinda low at those altitudes) and note the altitude.

This is the kind of situation where I would expect the P47 to show something, and the higher the speed used in step A the better.

XyZspineZyX
08-21-2003, 04:09 PM
Well, so much for my ideas.

I tried from 6000m at 850kph stopping at 400kph and second heavy line for climb angle. Not really much difference between the planes. Given the imperfections of the test (no G-meter for pull up into climb and even at 1/2 speed can't keep a perfect smooth constant climb angle) 200m difference at the end really doesn't mean much, and the results were basically like Isegrim got LA7,FW190>P47,Yak3

Tried same with third heavy line. Same as above.

I tried from 4000m at 850kph and stopping at 600kph with first heavy bar as climb angle. Here I only bothered with the FW190D and the Yak3. The FW was 150m better, which is actually less difference than I was expecting.

So now I think the problem is that when pilot's talk about significant differences they are talking about differences that from our point of view are rather small and hard to measure.