Spit/109 sea level speed comparisons in 1.08 beta patch

[Kurfürst]

Originally Posted by klem

5 mins was the instruction in the pilots notes. It did not mean instant failure.

I was more reflecting to the (baseless) part of the claim, that "Merlin engines should not overheat within 5 minutes"

Actually they can, like any other engine, depending on conditions.

The manual says that if possible, the pilot should not operate the engine for more than five minutes at + 6.25 (+12) boost / 3000 rpm, AND that the maximum oil and coolant (iirc 125 degrees Celsius) temperatures during that period are NOT to be exceeded. The overstepping five minutes is less a problem, it will wear out the engine quicker for sure, but temperatures will kill it much quicker. If you run the engine coolant/oil at 160 degrees Celsius it will fail anyway, and I would say, likely well before 5 minutes.

Given that combats usually last only a few minutes it should not be a problem too often. Its true though that information on the maximum time before failure needs to be found or, perhaps more correctly, information that will allow the devs to simulate properly the temperature effects of BCO and then, presumably, the temperature effects on the engine will already have been modelled....... ermmmm I say the latter with my tongue in my cheek.

I agree.

[ATAG_Snapper]

The Merlin engines in the Spitfire MK 1a 100 octane die at 97 C oil temp for all boost and rpms settings in beta 1.08.

[5./JG27.Farber]

Originally Posted by camber

* First, the CoD 109 has access to it's historical 1 min takeoff only boost (1.45ata), and can use it (unhistorically) practically continuously with no engine problems. This allows it to go 20kmh faster than the CoD Spit all out at +12psi.

Actually it can't just be used willy nilly. Activating it at the top of a "zoom" climb when pitch is at 12:00 and your hanging on the prop will blow the engine. I'd also like to add pressing wep at SL when already going all out throttle, pitch and speed at 460 (rarley 480) doesnt add any more speed. The wep seems to add more power at lower sppeds to me.


The graphs having different scales makes it very hard to compare, any chance of putting it all on one graph? - Or at least the same scaled graph?

FT = Full Throttle? I think nearly all the speed tests on the 109 were done at 1.3 or 1.35 Ata were they not? Not full throttle...

[Ze-Jamz]

Originally Posted by 5./JG27.Farber

Actually it can't just be used willy nilly. Activating it at the top of a "zoom" climb when pitch is at 12:00 and your hanging on the prop will blow the engine. I'd also like to add pressing wep at SL when already going all out throttle, pitch and speed at 460 (rarley 480) doesnt add any more speed. The wep seems to add more power at lower sppeds to me.

Your correct on WEP having no effect at higher ALT IMO..

Climbing yes but all out power no.

And I agree also about boost being used as often as you like in the 109...not true and I think this cones from pilots that don't fly it, do it high Altitude continuously and see what happens, so it continuously on max pitch and full throttle with low speed and your kill it too..

[5./JG27.Farber]

Originally Posted by Ze-Jamz

Your correct on WEP having no effect at higher ALT IMO..

Climbing yes but all out power no.

And I agree also about boost being used as often as you like in the 109...not true and I think this cones from pilots that don't fly it, do it high Altitude continuously and see what happens, so it continuously on max pitch and full throttle with low speed and your kill it too..

Yep and long periods over 1.3 and deffinatley over 1.4 (usually cos of wep) will destroy the engine even though temps and RPM are normal.

[camber]

Originally Posted by 5./JG27.Farber

Actually it can't just be used willy nilly. Activating it at the top of a "zoom" climb when pitch is at 12:00 and your hanging on the prop will blow the engine. I'd also like to add pressing wep at SL when already going all out throttle, pitch and speed at 460 (rarley 480) doesnt add any more speed. The wep seems to add more power at lower sppeds to me.


The graphs having different scales makes it very hard to compare, any chance of putting it all on one graph? - Or at least the same scaled graph?

FT = Full Throttle? I think nearly all the speed tests on the 109 were done at 1.3 or 1.35 Ata were they not? Not full throttle...

Hi Farber,

Sounds like I may be overstating the ease and safety of 1.45ata use in the 109. In my speed tests I tried restarting it a few times at SL and didn't see engine problems but didn't try many variations. I got 450kmh without and 470 kmh with it on, is that consistent with you?. The 1.45ata in combat makes it harder to work out how best to configure the 109 in CoD, if you gave the 109 500kmh at around 1.3ata and combat access to 1.45ata, you have a VERY fast bird indeed in CoD considering historical information.

For the 109 tests I left auto prop pitch on and had the throttle fully open, with the boost regulation giving 1.35ata or 1.45ata. FT is full throttle as you surmise.

I scaled the plots seperately because I wanted to talk about relative speeds in real life and game. Both plots have a 120kmh range on the y axis, the CoD one starts 50kmh lower because all speeds in CoD are roughly 50kmh low. These tests are really a bit basic..only sea level max speeds done singly offline.

[Robo.]

Originally Posted by camber

Sounds like I may be overstating the ease and safety of 1.45ata use in the 109.

I guess that is because this is a fairly new feature in recent beta patches (1.07 onwards afik). It used to be just as you described it...

I haven't got enough hours in 109 in 1.08 to comment on that to be honest. I managed to damage the engine when I forgot to open the water rad, but I never damaged it by using the WEP as long as my rpm weren't too high.

[Ze-Jamz]

Originally Posted by Robo.

I guess that is because this is a fairly new feature in recent beta patches (1.07 onwards afik). It used to be just as you described it...

I haven't got enough hours in 109 in 1.08 to comment on that to be honest. I managed to damage the engine when I forgot to open the water rad, but I never damaged it by using the WEP as long as my rpm weren't too high.

The effect you get from execissve use at certain instances of Boost is not the same as cooking your engine throuh heat, I'm not sure what damage is modeled in game but you suffer with lack of power and can't seem to get your rpm as high as normal..can't remember the exact figure as I try not to do it often

[5./JG27.Farber]

Originally Posted by camber

Hi Farber,

Sounds like I may be overstating the ease and safety of 1.45ata use in the 109. In my speed tests I tried restarting it a few times at SL and didn't see engine problems but didn't try many variations. I got 450kmh without and 470 kmh with it on, is that consistent with you?. The 1.45ata in combat makes it harder to work out how best to configure the 109 in CoD, if you gave the 109 500kmh at around 1.3ata and combat access to 1.45ata, you have a VERY fast bird indeed in CoD considering historical information.

For the 109 tests I left auto prop pitch on and had the throttle fully open, with the boost regulation giving 1.35ata or 1.45ata. FT is full throttle as you surmise.

I scaled the plots seperately because I wanted to talk about relative speeds in real life and game. Both plots have a 120kmh range on the y axis, the CoD one starts 50kmh lower because all speeds in CoD are roughly 50kmh low. These tests are really a bit basic..only sea level max speeds done singly offline.

Thank you for you intelligent and polite reply. Hopefully it can be an example for this thread so it doesnt get locked.

My squad mates and I have been discussing the difference between the E4 auto pitch and the E1 and E3 manual pitch which is quite different. I would also go as far to say when your using autopitch your almost using the AI FM in some respects. The exact difference is hard to describe and establish exactly... The auto pitch also runs at a lower RPM than I would manually, although it gets more acceleration, better fuel economy and is overall superior except when you rapidly climb and dive continiously and it cannot keep up with you. 5./JG27Gruber could explain more on this than I think, I will see if he wants to contribute.

I can achieve 460kmh sea level with out any wep during the acceleration... Occasionally if I have my aircraft trimmed perfectly and the planets align I can get a steady 480 kmh... At 5km altitude its more like 420kmh.

Klem started a thread about speed and the 109 was discussed also. I made some quick tracks [Strike]which I will attempt to attach here.[/Strike] (they are messed up, I will fraps it and upload to youtube...) Close to sea level tests and 5km level flight speed tests 1.3 Ata and 2350 U/pm if I recall. I think these runs were made in 1.07. As far as I am aware the only difference to the 109 FM is the rad drag... - Which is neglible to a degree.

-Ultimatley, I am only Human. I'm proberbly not the best at flying straight and level and maybe I am even doing it wrong? I will let others be the judge of it.


EDIT1: WOW was I wrong?! 100% Fuel gave some interesting results but I need to test 50% also for comparison. There have been changes to Bf109 FM in 1.08.

[41Sqn_Banks]

Interesting .... http://www.spitfireperformance.com/n3171-cooling.jpg

From: http://www.spitfireperformance.com/n3171.html