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View Full Version : UBI AI, FM, Range and Time



PhantomKira
10-07-2010, 06:11 AM
I've noticed a few oddities with regards to aircraft range and flight time.

For clarity, I'll stick to just the Pacific aircraft. Specifically, I tested the P-51, P-47, P-38, F6F and F4U.

First, regardless of aircraft, when doing range tests, if I let the AI handle the flight, invariably I run out of fuel long before my wingmen do, even if I have not touched the controls once (AI flys). What's with that? The AI should fly my plane the same as it does the others, so we should run out of fuel at the same time, right?

Second, I understand that the P-47D had "relatively" short legs. And that in Europe, the P-38 didn't go as far as the P-51. However, many of my books indicate that P-38s were running 2,000 mile missions by late war, which is exactly the range that they say the P-51 had. I would think the P-38L Late would be comparable in range to the P-51, but it isn't even close (way less). My math says it should go further. The math's not exact, but, including climb to altitude until dead dry without drop tanks, here it is:

Waypoints were set for 10000m, and 400kmh. Aircraft used were the latest version available.

P38 30000m 340kmh x 3h45min = 1275km; 792.248sm; 688.445nm

P51 30000m 380kmh x 3h10min = 1216km; 755.587sm; 656.587nm

P47 30000m 380kmh x 2h25min = 931km; 578.496sm; 502.700nm

F6F 30000m 220kmh x 3h40min = 814km; 505.796sm; 439.525nm

F4U 30000m 220kmh 814km x 3h40min = 814km; 439.525nm

F6F and F4U are identical. Was this done on purpose?

So, instead of the 38 and 51 going the same distance, based on speed and time, the 38 goes about 3/4 the distance. Hmmmm....

Edit: Waypoints at 10000m,32808.399ft. Statute Mile and Nautical Mile equivalents added.

PhantomKira
10-07-2010, 06:11 AM
I've noticed a few oddities with regards to aircraft range and flight time.

For clarity, I'll stick to just the Pacific aircraft. Specifically, I tested the P-51, P-47, P-38, F6F and F4U.

First, regardless of aircraft, when doing range tests, if I let the AI handle the flight, invariably I run out of fuel long before my wingmen do, even if I have not touched the controls once (AI flys). What's with that? The AI should fly my plane the same as it does the others, so we should run out of fuel at the same time, right?

Second, I understand that the P-47D had "relatively" short legs. And that in Europe, the P-38 didn't go as far as the P-51. However, many of my books indicate that P-38s were running 2,000 mile missions by late war, which is exactly the range that they say the P-51 had. I would think the P-38L Late would be comparable in range to the P-51, but it isn't even close (way less). My math says it should go further. The math's not exact, but, including climb to altitude until dead dry without drop tanks, here it is:

Waypoints were set for 10000m, and 400kmh. Aircraft used were the latest version available.

P38 30000m 340kmh x 3h45min = 1275km; 792.248sm; 688.445nm

P51 30000m 380kmh x 3h10min = 1216km; 755.587sm; 656.587nm

P47 30000m 380kmh x 2h25min = 931km; 578.496sm; 502.700nm

F6F 30000m 220kmh x 3h40min = 814km; 505.796sm; 439.525nm

F4U 30000m 220kmh 814km x 3h40min = 814km; 439.525nm

F6F and F4U are identical. Was this done on purpose?

So, instead of the 38 and 51 going the same distance, based on speed and time, the 38 goes about 3/4 the distance. Hmmmm....

Edit: Waypoints at 10000m,32808.399ft. Statute Mile and Nautical Mile equivalents added.

Erkki_M
10-07-2010, 07:23 AM
Easy. Droptanks + different optimal cruise speeds & altitudes.

M_Gunz
10-07-2010, 09:56 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PhantomKira:
The AI should fly my plane the same as it does the others, so we should run out of fuel at the same time, right? </div></BLOCKQUOTE>

If the autopilot and AI are the same and the planes are the same then ----

Romanator21
10-07-2010, 01:17 PM
I remember when I was playing IL-2 Forgotten Battles (v.2.01) years ago the same thing happened when I was flying an I-16 as a patrol (the boring mission with the triangular set of numerous waypoints). I set my I-16 to AI, but I ran out of fuel before anyone else - behind enemy lines. http://forums.ubi.com/images/smilies/16x16_smiley-mad.gif The same thing happened to me in a Zero when I flew the Pearl Harbor mission for the first time.

Maybe the AI doesn't change every parameter you leave the plane with once you activate it? I'm sure that if you were flying and had control the whole time, you could increase that range.

BillSwagger
10-07-2010, 01:32 PM
i dont think AI adjust prop pitch for you the way it does the other AI planes.


Bill

ElAurens
10-07-2010, 06:02 PM
I've thought that from day one in the original IL2 that no aircraft in the sim has the range of it's real world counterpart.

PhantomKira
10-07-2010, 08:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Romanator21:
I set my I-16 to AI, but I ran out of fuel before anyone else - behind enemy lines. :angry. </div></BLOCKQUOTE>

I've had this happen before. With the British Far East campaign in Hurricanes. Almost every mission, I ended up coming back on fumes, if at all. Some I couldn't complete due to lack of fuel. It's really surprising that the developers made this campaign that way in the first place.

AI wingmen have ridiculous fuel management and fly longer than the human controlled aircraft, despite the fact that they absolutely MUST be doing more throttle adjusting to maintain formation and cover me, etc, which would result in higher fuel consumption than the lead airplane, even with perfect control coordination and engine management.

Romanator21
10-07-2010, 09:56 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">i dont think AI adjust prop pitch for you the way it does the other AI planes. </div></BLOCKQUOTE>

I just did a quick test, and I can say that it's absolutely true. The AI also can't change mixture and superchargers for you, only the throttle.

I can only imagine that this bug is related to the old engine management system in IL-2 which only had "Power". Prop-pitch, mixture, superchargers, radiators etc could not be controlled by the player at all in the earliest versions of the game. I guess the AI was never updated or adapted to handle this. This would also explain why the AI can always travel faster than us, never overheat, etc - they don't have any systems to manage!

This has a huge impact on fuel management. If you activate the AI while your P-Pitch is still 100% for instance, this is going to murder your fuel efficiency. And the AI has no programming to change it!

horseback
10-07-2010, 10:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Second, I understand that the P-47D had "relatively" short legs. And that in Europe, the P-38 didn't go as far as the P-51. However, many of my books indicate that P-38s were running 2,000 mile missions by late war, which is exactly the range that they say the P-51 had. I would think the P-38L Late would be comparable in range to the P-51, but it isn't even close (way less). </div></BLOCKQUOTE>
What you miss here is that the long range techniques developed by the (veteran) P-38 units in the Pacific did not get back to the comparatively inexperienced P-38 groups in the 8th and 9th Air Forces. Applying similar techniques allowed the very long range P-51D escort missions from Iwo to Japan. It's revealing that they didn't use the P-38Ls for those missions as well or instead.

My guess is that the Mustang could be stretched a good bit farther than the P-38.

cheers

horseback

WTE_Galway
10-10-2010, 06:04 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Romanator21:
I guess the AI was never updated or adapted to handle this. This would also explain why the AI can always travel faster than us, never overheat, etc - they don't have any systems to manage!
</div></BLOCKQUOTE>

Well on autopilot your plane doesn't overheat either.

Its a well known offline exploit - use autopilot to takeoff and get to the combat and you are starting the fight with a cold engine.

GerritJ9
10-11-2010, 10:42 AM
The Hawker Hurricane had a short range IRL, so some of the Far East campaign missions would have been impossible IRL as well as in IL2. Escorting bombers from Seletar to Kuala Lumpur and back simply was not on with Hurricanes- even more so when forced to grapple with enemy fighters. The fault lies more with whoever wrote the scenarios for the campaign than with a possibly unrealistic range- he/she should have checked whether a real Hurricane could have carried out such a mission in the first place, and tested the mission before adding it to the campaign.

PhantomKira
10-12-2010, 08:20 AM
horseback, you have some good points. I'll add that the P-51 drivers got special training that no one else got. Revealing when someone states offhandedly (or not so), that the P51 won the war. Or that it was "the best fighter" never mind the fact that the pilots cut their teeth and learned their trade on other types before transferring to the '51. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

I've done a bit of further testing. By adjusting prop pitch (to 5%) and consequently cutting my RPMs back to 2600 and 2400 (as dictated by Lindbergh), the Manifold Pressure went way up (also as stated by reports), and I ran the AI out of fuel. It did not, however result in any increase in range; if anything, a decrease. Endurance, yes, but not range.

Sidenote: I'm having no luck with mixture control. I've mapped it in the controls, but the sim doesn't seem to recognize it... Any ideas?

Romanator21
10-12-2010, 10:32 AM
Some planes (American especially) have automatic mixture (rich) control. As of yet you can't do anything, except maybe increase mixture to 120% to help cool your engine. DT is fixing this.

5% is much too low to cruise on. Your propeller would practically be windmilling and doing nothing. Setting throttle higher than that would, in reality, blow up your engine. (Maybe you meant 50%?). Try to find an aircraft operating manual on the net which should give the best RPMs and manifold pressure for efficient cruise.

PhantomKira
10-12-2010, 05:42 PM
Exceedingly rich mixtures have the adverse effect of fouling the spark plugs. Not that we have to worry about our virtual plugs...

Yeah, I'm well aware of the fact that anything under about 70% is too low pitch, I was just trying to get the 2600 RPM with "high" MP settings, any way I could. Turns out "high" is, in this case, 60" plus. No wonder they were worried about the engine going "BOOM"! And that with mixture set to "Auto Lean". Talk about burning up the engine and destroying it however one can!

M_Gunz
10-12-2010, 08:20 PM
Find out what settings Lindbergh arrived at for P-38's in the Pacific. (http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/2091032543)

Got the revs....

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">"Mr. Lindbergh" wanted to explain how to gain more range from the P-38s. In a pleasant manner Lindbergh explained cruise control techniques he had worked out for the Lightning's: reduce the standard 2,200 rpm to 1,600, set fuel mixtures to "auto-lean," and slightly increase manifold pressures. This, Lindbergh predicted, would stretch the Lightning's radius by 400 hundred miles, a nine-hour flight. When he concluded his talk half an hour later, the room was silent. </div></BLOCKQUOTE>

BTW 1600 is 53% of 3000.

Erkki_M
10-13-2010, 12:32 AM
Also note that best cruise range was usually achieved at very high altitudes too. For Zeke the best alt was, if I dont remember all wrong, pretty exactly 7000m. Probably even higher for your test planes P-51, P-38 and P-47.

Col_SandersLite
10-13-2010, 08:34 AM
Cruise will be best at the engines peak performance altitude. Check the p-38 max tas altitude in il-2 compare. About 25,000 feet.

I did test the p-38 numbers in sim against a p-38 range card back in the PF days (4.01m maybe?). It was pretty accurate when the revs where high, but the accuracy in the low rev department just wasn't a very good match. I didn't really care all that much as combat is always flown in high revs and basically nobody cares to fly a full 10 hour patrol where literally nothing happens for over nine hours. Missions tend to be in the half hour to one hour flight time range, and this is quite easily within the fuel capacity of the majority of the aircraft in the game.


Just remember, that reducing your prop pitch/throttle will increase your range, but there's a limit to this. What you're looking for is where the fuel consumption rate compared to speed will net the best result. If you drop your speed *too much* you'll stay in the air longer, but not go as far because you're moving slower and therefore have fallen out of the butter zone.

My personal experience is that for all the adjustable CSP fighters, setting your prop pitch to 40% and throttle to 50% will net you a fairly fast cruise that will give you more than ample fuel economy and keep the engine cool. Try this as a starting point and adjust to get the desired speed.

For the fully automatic fighters (like the 109/190) don't worry about pitch, and just use the throttle to get the desired cruising speed. I think that in the 109F2/4 economy cruise is about 300 kph IAS at 5000m. This is IIRC, about 40% throttle with prop pitch in automatic mode. Though I must note that economy cruise is not the smartest setting to use in a hot zone. You really want to pick the speed up to a combat cruise instead (something like 400kph ias at 5000m using 60% throttle would do ok).