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DKoor
06-05-2009, 06:20 AM
<pre class="ip-ubbcode-code-pre">
TYPE ALT (m) SPEED v4.08 (kph)OVERHEAT DURAB. (s) WEP time (m) 110(100)%-WEP canopy open,no wep YEAR
F4U-1D SL 576 608 15 559 542 1944
F4U-1D* 6900 680 ? 15 685 664 1944
F6F-5 SL 521 602 22,5 513 500 1944
F6F-5* 7100 619 ? 22,5 632 617 1944
P-47D22 SL 550 601 26 540 - 1943
P-47D22* 9000 703 ? 26 691 - 1943
P-47D27 SL 578 601 26 545 - 1944
P-47D27* 7500 710 ? 26 669 - 1944
P-47D_LATE SL 584 603 26 542 - 1944
P-47D_LATE* 7100 724 ? 26 672 - 1944
</pre>

Basics of the boost systems for P-47 in comparison with F6F & F4U... while I didn't expect them to be different they clearly are (in game?).
I don't know how to explain the situation on the table... F6F & F4U actually achieves its top speed only after boost runs out.
And it only happens at top speed (at altitude), on deck fighter regularly loses power after boost is depleted, as can be seen on table.

I saw that some of you guys know a lot about this stuff, so I thought maybe you can clear this one up too.

JtD
06-05-2009, 07:00 AM
I don't quite get your point.

The 110(100)% column are speeds as achieved without water injection? Where do they come from?

The v4.08 speeds come from where?

DKoor
06-05-2009, 07:09 AM
v4.08 speeds come from my actual tests of maximum level speed in game... since I tested them heading 270 at Crimea map on realistic physics settings, those may differ from actual values by max 2-3kph.

Overheat durability - means how long a fighter may fly under constant overheat before loss of speed is experienced.
WEP time - time available for boost.
110(100)%-WEP - is maximum speed (at max throttle settings) without WEP (boost) engaged... in practice that meant that I had to fly some fighters untill their WEP runs out then test their maximum speed (specifically, those above are all on 110% throttle, max available but some fighter like Spitfire and Lavochkin have only 100% as max throttle settings).
Canopy open, no WEP - same as with 110(100)%-WEP , with open canopy.

Here is comparison with IL-2 Compare v4.07 max speeds;

<pre class="ip-ubbcode-code-pre">
TYPE IL-2 C v4.07 SPEED v4.08 (kph)ALT (m)
F4U-1D 565 576 SL
F4U-1D* 673 680 6900
F6F-5 512 521 SL
F6F-5* 615 619 7100
P-47D22 538 550 SL
P-47D22* 693 703 9000
P-47D27 566 578 SL
P-47D27* 700 710 7500
P-47D_LATE 572 584 SL
P-47D_LATE* 715 724 7100
</pre>

...most fighters tested have experienced increase in speed some more some less, but only few of them like TA-152C and Spitfire Mk.VIII are actually slower in v4.08...

JtD
06-05-2009, 07:24 AM
Did you check on the boost gauge if the boost dropped when the water injection ran out?

Water injection doesn't necessarily increase power output, it just allows higher boosts to be used without ruining the engine. The higher boost gives the extra power.

Assuming that the boost does not drop, the speeds should not change significantly (but the plane is lighter now, so a little plus), but the engine should not be able to cope with the high boost as well as before, or, like in the 109, not cope with it at all.

WRT sea level top speeds, there is a considerable difference between flying at 2 meters and flying at 20 meters. What alt did you fly at?

Did you go by hand or by autopilot? Is your speed converted IAs or TAS from cockpit off gauge?

Just curious, would like to see more of your results.

DKoor
06-05-2009, 07:57 AM
<STRIKE>Yes boost gauge changes value for sure...</STRIKE> I will post you the track, I hope I will find it so you will see it for yourself.

I couldn't reasonably fly lower than 10m so I have chosen that alt for "deck" speed, and I conducted tests via autopilot (there is too much inconsistency if flown manually). Speeds are read after several minutes of constant max speed or max level speed until the overheat ruins the engine... all in all, pretty precise system.
Start speed was around 400kph... with a bit of extra altitude (to stabilize airplane easier).

Speeds are read from comic gauge, i.e. cockpit off (wonder woman).

DKoor
06-05-2009, 09:36 AM
Edit!

Boost value doesn't changes at all!
None of the important gauges changes value at all except speed gauge... this doesn't look right TBH.

From the Hellcat gauges;

At speed 619kph (max) on alt 7100m with boost;

Manifold Pressure - 53,5
RPM - 2700
Airspeed - ~225


At speed 632kph (max) on alt 7100m without boost;

Manifold Pressure - 53,5
RPM - 2700
Airspeed - ~230


Similar "behaviour" could be expected from the Corsair gauges as well...
http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif

Here is a track for download;
http://www.esnips.com/doc/3c2c...f/spl_F6F-5_632_7100 (http://www.esnips.com/doc/3c2c96c6-1767-417b-a88f-52432229cd7f/spl_F6F-5_632_7100)

JtD
06-05-2009, 10:13 AM
Thanks for the information, I'll be looking at the track when I get back home next week.

Since you brought something up I didn't know about I'll probably be doing some testing on my own. I think I will be trying out top speeds on several altitudes with various charger stages with and without water injection - unless someone who's already done that comes up with the results in the meantime.

As for it being realistic - it is not.

DKoor
06-05-2009, 10:28 AM
Thanks for your interest matehttp://forums.ubi.com/groupee_common/emoticons/icon_cool.gif.
Yes one needs to be careful with Hellcat supercharger it has three stages (I ran it on stage 3 I hope I wasn't mistaken therehttp://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif).
As for other general settings, as usual... closed rad, 110% throttle, canopy closed, Crimea map, 12' o clock...

DaimonSyrius
06-05-2009, 11:49 AM
Originally posted by DKoor:
[...]in practice that meant that I had to fly some fighters untill their WEP runs out then test their maximum speed[...]

Hi DKoor,

Maybe this is a naive question, but what about fuel load? I mean, for instance with the F6F, in order to run out of WEP you have to fly at 110% throttle during more than 20 min, that surely will burn a significant amount of fuel ---> less weight, more speed. Were your speed tests with working WEP done with the same fuel load (not at flight start, but at the time of checking max speed)?

Cheers,
S.

DKoor
06-05-2009, 12:47 PM
Originally posted by DaimonSyrius:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DKoor:
[...]in practice that meant that I had to fly some fighters untill their WEP runs out then test their maximum speed[...]

Hi DKoor,

Maybe this is a naive question, but what about fuel load? I mean, for instance with the F6F, in order to run out of WEP you have to fly at 110% throttle during more than 20 min, that surely will burn a significant amount of fuel ---> less weight, more speed. Were your speed tests with working WEP done with the same fuel load (not at flight start, but at the time of checking max speed)?

Cheers,
S. </div></BLOCKQUOTE>Hey, long time no see! http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif
Glad to see that you're still around.

From my experience this isn't an issue with fuel (I ran all tests with default load and 100% fuel), because speed doesn't change at all while flying with boost on, but once boost runs out speed rapidly rises; you can see the difference immediately.

DKoor
06-05-2009, 01:33 PM
Also one quite funny error in the aircraft guide for F6F-5... it says to "switch supercharger states at 2800m (8200feet) and 8100m (26570feet)" but in fact when I leave it in position 2 at 7100m it achieves only 575kph (with boost) and in position 3 it achieves 619kph (and also higher pressure), needles to say it looks funny http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif .

Daiichidoku
06-05-2009, 01:36 PM
take the jug over 8000m @110% w/water in level flight

then drop throttle to 100% w/ no water

watch the RPMs.....

DKoor
06-05-2009, 01:56 PM
I just tried it... 8500m, P-47D_LATE. I get almost no difference in rpm (very little diff logically in favor of boost). Speed also drops when boost is not used... manifold pressure drops significantly.
My untrained eye can't spot some obvious error http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif .

Daiichidoku
06-05-2009, 03:43 PM
when you go down to 100% from 101%+, RPM needle jumps up a bit before it settles down again

when you go up to 101%+ from 100%, RPM needle drops a bit before it settles back up

DKoor
06-05-2009, 04:47 PM
Originally posted by Daiichidoku:
when you go down to 100% from 101%+, RPM needle jumps up a bit before it settles down again

when you go up to 101%+ from 100%, RPM needle drops a bit before it settles back up http://forums.ubi.com/images/smilies/blink.gifWeird.

idonno
06-05-2009, 05:12 PM
The RPM's should remain constant.

These airplanes have CONSTANT SPEED propellers. That means that the prop adjusts it's pitch in order to maintain whatever rpm's it is set for.

You can reduce the throttle to the point that the prop can't adjust it's pitch enough to maintian the set rpm's, but above a certain manifold pressure you can slowly advance the throttle and watch the rpm's remain constant as the manifold pressure increases.

R_Target
06-05-2009, 05:14 PM
Originally posted by DKoor:
Thanks for your interest matehttp://forums.ubi.com/groupee_common/emoticons/icon_cool.gif.
Yes one needs to be careful with Hellcat supercharger it has three stages (I ran it on stage 3 I hope I wasn't mistaken therehttp://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif).
As for other general settings, as usual... closed rad, 110% throttle, canopy closed, Crimea map, 12' o clock...

That's correct, 3rd stage. With WEP I change SC at 6,000ft. and 18,000 ft.; those gave the best results when I tested Hellcat speeds a couple years ago.

Weird results though eh? I never bothered to test post-WEP speeds in the F6F. Last time I checked, it takes 10 minutes to burn through the water injection, and I could never wait that long. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

DKoor
06-05-2009, 05:16 PM
Originally posted by idonno:
The RPM's should remain constant.

These airplanes have CONSTANT SPEED propellers. That means that the prop adjusts it's pitch in order to maintain whatever rpm's it is set for.

You can reduce the throttle to the point that the prop can't adjust it's pitch enough to maintian the set rpm's, but above a certain manifold pressure you can slowly advance the throttle and watch the rpm's remain constant as the manifold pressure increases.
I can see the point however that still doesn't explain why the manifold pressure remains constant, and pretty much everything else and speed raises a bit after boost runs out?
At first glance doesn't really make any sense.

DKoor
06-05-2009, 05:25 PM
Originally posted by R_Target:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DKoor:
Thanks for your interest matehttp://forums.ubi.com/groupee_common/emoticons/icon_cool.gif.
Yes one needs to be careful with Hellcat supercharger it has three stages (I ran it on stage 3 I hope I wasn't mistaken therehttp://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif).
As for other general settings, as usual... closed rad, 110% throttle, canopy closed, Crimea map, 12' o clock...

That's correct, 3rd stage. With WEP I change SC at 6,000ft. and 18,000 ft.; those gave the best results when I tested Hellcat speeds a couple years ago.

Weird results though eh? I never bothered to test post-WEP speeds in the F6F. Last time I checked, it takes 10 minutes to burn through the water injection, and I could never wait that long. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>Yeah... there are only a few "interesting" test results out of dozens I tested... for instance I was amazed to see that P-400 and MiG-3AM-38 never overheat at top speed level flights including deck top speed flights and few others too... etc.
BTW mate F6F in game has 22,5min of boost, that should be enough for the whole combat in most cases. Also shares neat feature with several other types, never to overheat at higher altitudes http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif .

R_Target
06-06-2009, 08:07 AM
Originally posted by DKoor:
Yeah... there are only a few "interesting" test results out of dozens I tested... for instance I was amazed to see that P-400 and MiG-3AM-38 never overheat at top speed level flights including deck top speed flights and few others too... etc.
BTW mate F6F in game has 22,5min of boost, that should be enough for the whole combat in most cases. Also shares neat feature with several other types, never to overheat at higher altitudes http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif .

I think 22.5 minutes is bogus. I'll check some books and docs to see if I can find a correct time. The fluid tank on F6F is 16 gallons whereas the P-47 has a 30 gallon tank; so I'm guessing that the Hellcat should only have half the time of the Thunderbolt. High altitude overheat accuracy is problematic because the limiting factor is cylinder head temperature, which can't be measured because the temperature gauge in the cockpit is wrong by 100C. I did get it to overheat at 25,000 ft. once, but I had to climb from SL on WEP to do it. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif At any rate, the manual for actual F6F says WEP should be run continuously for only 5 minutes. It used to be that 10 minutes of overheat running with or without WEP gave "squeaky" engine and massive power loss.

DKoor
06-06-2009, 11:35 AM
Thanks for the input http://forums.ubi.com/images/smilies/25.gif always appreciated because I know your interest about Hellcats. http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

R_Target
06-11-2009, 05:34 AM
I'm not having a whole lot of luck, but I have found one doc about testing higher boost pressures at Combat Power. The testing schedule calls for 2 five minute runs at WEP in the same flight. So that would be ten minutes on one 16 gallon tank, but the doc doesn't positively state whether or not ADI fluid is exhausted after ten minutes operation.