Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: Jochen on August 24, 1999, 08:37:00 AM
-
How accurately WEP or other performance improving devices will be modeled in different planes?
For what I know, USAAF used water injection and Luftwaffe water/metanol injection MW-50 in low altitude and GM-1 in high altitude. Luftwaffe also used extra fuel injection to charger inlet to increase power of BMW 801 radials in FW 190F series below 1 km. All these gave somewhat significant increase in the performance region it was designed.
Ordinary WEP was (or I think so) the last several centimeters of throttle, giving the maximum power without any special devices.
The other game has only a generic WEP which is not very accurate representing some combinations. Many real planes had WEP and in addition to this MW-50, GM-1 or similar device. In the other game, when you apply WEP you might use performance improving device or not. To this day, it is not fully clear what kind of devices were modeled in Bf 109G-6 or in all Fw 190 series planes.
MS CFS has pretty accurate WEP modeling and some simulations under development will propably model these things too. I hope that AH will not be any worser.
------------------
Obfr. jochen 'Stern von Afrika' 2./ Jagdgeschwader 27 'Afrika'
-
Another point of interest are superchargers. The F4U for example has a 2-stage supercharger set manually for 'neutral' or 'low & high blower', this working in concert with water/methanol injection. I'm curious wheter the blower power will be built into the standard throttle control with the switch from low to high blower occurring automatically at altitude, or wheter it will be a manual feature (the latter preferred).
Also the 5 minute WEP standard in the other game was very general and incorrect in many cases. I've heard stories about WEP being used from 20 minutes up to an hour before having to be disengaged. Of course the terrains are scaled down and I could see the water/methanol limits being applied here but shouldn't actual WEP (full throttle) be limited only by engine temp? Say, unusable during overheat (red light) + 2 minutes for proper cooling? It could be modeled as 'unavailable' or the user could push it and risk engine malfunction (the latter making for better gameplay). (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
All in all I'm eager to see how you guys work this one out. It's gonna be a real blast to play with the final product regardless. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
(http://members.aol.com/tullisart/0622.gif)
------------------
Windle
*Future* Aces High VF-17 'Jolly Rogers' 8X
-
just FYI,
at least on the U.S. birds most of those blowers were manualy set thus in a combat situation you could have been at 20,000 feet in 'high' blower when you either chased someone down or were chased down. the result? very high manifold pressures that could and would blow your engine and your cooling (if water cooled) before you had a chance to do anything about it.
shdo
-
I've heard stories about WEP being used from 20 minutes up to an hour before having to be disengaged. Of course the terrains are scaled down and I could see the water/methanol limits being applied here but shouldn't actual WEP (full throttle) be limited only by engine temp? Say, unusable during overheat (red light) + 2 minutes for proper cooling?
If my memory serves me right, Fw 190 was able to use MW 50 for 20 minutes continuously and it had enough methanol/water for 40 minutes. In small arena that translates to pretty serious performance advantage, basically you can fly with WEP all the time.
Here is the key question:
Will the planes be tuned only to arena use similar the MA in the other sim or are they modeled 100% correctly to suit scenarios?
If the main target is arena use, some detuning of planes could be done to achieve balance since everybody can fly what they want. If some plane becomes too good for its timeframe, everybody will fly it. To achieve some variety, performance of planes could be made more equal than it was in WW II.
On scenarios, plane type ratios can be controlled and even 'superior' planes can be used but in smaller numbers.
I would like to hear comments about this from designers.
------------------
Obfr. jochen 'Stern von Afrika' 2./ Jagdgeschwader 27 'Afrika'
-
WEP duration is treated fairly generically for gameplay purposes. Most planes were only rated for 5 minutes or so, but that doesn't necessarily mean their engines couldn't handle longer periods. We don't have to deal with aircraft maintenance, so there's nothing to stop us from abusing our planes without imposing some artificial limitations. In the real world, a pilot who treats his plane like a rental car will suffer much ire from his maintenance crew, engineering officer, and ultimately his commanding officer.
The differences between emergency power and other systems like water injection are modeled.
------------------
Doug "Pyro" Balmos
HiTech Creations
-
PYRO how about some maintenance problems as in over revving the engine for to long of a duration. Make us fly the planes not ride and kill in them. Speeking of killing the creators guns will be turned down once online wont they say at least to 5%.
------------------
Tommy (INDIAN) Toon
http://www.geocities.com/~tltoon
-
Jochen, do you remember the whole debate on the subject of red stripe on the 109's gear ?
Ik wrote that it indicated to the ground crew that that 109 has GM1 installed which requires 100 octane gasoline.
If you read the history you will know that gas was about as common in LW as snow Etiopia.
So if we are gonna get into "somewhat avaiable" advancements i want spit 9 modified with used 150 octane gas and could run with mustangs...
------------------
(http://www.raf303.org/banner.gif)
Bartlomiej Rajewski
S/L fd-ski Sq. 303 (Polish) "Kosciuszko" RAF
www.raf303.org (http://www.raf303.org)
-
Jochen, do you remember the whole debate on the subject of red stripe on the 109's gear ?
Ik wrote that it indicated to the ground crew that that 109 has GM1 installed which requires 100 octane gasoline.
If you read the history you will know that gas was about as common in LW as snow Etiopia.
So if we are gonna get into "somewhat avaiable" advancements i want spit 9 modified with used 150 octane gas and could run with mustangs...
Oh, you got it wrong:
109's with the MW 50 system used 96 or 100 octane C3 fuel, and had the landing gear legs painted red in order to remind the ground crew of the fuel requirements (87 octane fuel would ruin the engine).
It was MW 50 that was indicated by red landing gear struts. I don't have info about GM-1 and it's fuel requirements.
Sure, in the end of the war, LW was having serious fuel supply problems. Despite reading many books about this era, I haven't found indication that 100 octane fuel supply was considerable lower than any other fuel. Care to give your source for this info?
When MW 50 and GM 1 were taken to use, fuel situation was considerable better.
I have impressions that 150 octane fuel was mainly used in planes which chases down V-1's?
------------------
Obfr. jochen 'Stern von Afrika' 2./ Jagdgeschwader 27 'Afrika'
-
that was MW 50 fd-ski, not GM-1.
GM-1 boost was widely used in the 109 series from the E-7 on, and did not require 96 or 100 octane fuel. I have always read that MW 50 required 96 or 100 octane, C3 fuel. However just recently funked had an inquiry with this RAF historian who said records indicate MW 50 could be used with 87 octane fuel too. That would explain why I have never seen a picture of a 109G-6 with a C3 octane rating instead of 87, even though we know MW 50 was used in the 109G-6 (Erich Hartmann wrote about requesting MW 50 kits for his gruppe's 109G-6's because Russian aircraft had become more formidable). We need more research on MW 50, but we can be positive that GM-1 was widely used in the 109G-6.
------------------
[This message has been edited by -ik- (edited 08-26-1999).]
-
MW-50 didn't require any special fuel.
But MW-50 was used as an anti-detonant to enable increased manifold pressure. By definition, higher octane gas also enables increased manifold pressures without detonation.
The octane requirements were based on the MP that the engine would be run at during MW-50 usage.
I'm not getting this from a Luftwaffe source, this is just how you use methanol-water injection. My dad did his thesis on turbosupercharging and methanol-water injeciton. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
[This message has been edited by funked (edited 08-26-1999).]
-
Of course, those engines (DB605ASOM?) using MW-50 and hi-octane (93?) fuels didn't last very long, and used heaps more fuel too (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
I imagine those Spit MkXIV's running 25lbs boost/150 octane fuel had short engine life too.
-
Never really liked fishing... but it looks like I have potential..... talk about stirring up the nest (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Jochen - to answer your questions - 100 octane aviation gas was widely avaiable for Allies for US- on the other hand Germany had trouble GETTING enough gas not to mention redefining it...
I'm at work now and don't have books here, but i'll look it up. I remember reading that LW aircraft performance would be somewhat better then normal had they had gas Allies used... but they didn't...
------------------
(http://www.raf303.org/banner.gif)
Bartlomiej Rajewski
S/L fd-ski Sq. 303 (Polish) "Kosciuszko" RAF
www.raf303.org (http://www.raf303.org)
-
<swims by the bait fd-ski has just cast, barfs and swims away> (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
-
Never really liked fishing... but it looks like I have potential..... talk about stirring up the nest
Heh, I tried same thing in A.G.W with Spitfire Mk.IX c and e wing, it worked great (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
I try to build up patience and dicipline not to reply all 'suspicious' posts but it's hard to know when one is serious or is he just fishing.
Oh, btw Pyro, does AH Spit IX have early c wing or later e wing? And what is availability of negative G devices in early Mk.V's and Mk.IX's?
<smack> ouch!
just kidding fd-ski, just kidding (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Jochen - to answer your questions - 100 octane aviation gas was widely avaiable for Allies for US- on the other hand Germany had trouble GETTING enough gas not to mention redefining it...
I'm at work now and don't have books here, but i'll look it up. I remember reading that LW aircraft performance would be somewhat better then normal had they had gas Allies used... but they didn't...
This was surely the case in late war. But I almost can bet that in early war LW had better fuel situation than RAF because Germany had Romanian and southern russia oilfields and their refineries were pretty much intact. On the other hand RAF and Britain were under strict sea blockade and their own oil refineries were bombed to tiny bits.
Oh those happy days for Lufwaffe...
(http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
------------------
Obfr. jochen 'Stern von Afrika' 2./ Jagdgeschwader 27 'Afrika'
-
This was surely the case in late war. But I almost can bet that in early war LW had better fuel situation than RAF because Germany had Romanian and southern russia oilfields and their refineries were pretty much intact. On the other hand RAF and Britain were under strict sea blockade and their own oil refineries were bombed to tiny bits.
Oh those happy days for Lufwaffe...
Oops! Nearly hooked me there.
------------------
-----------
-bmjk-
617 Squadron RAF
-
our fuel was better than your fuel! Was not! Was to! Was not! Was to! nya nya nya! (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
-
Jochen:
FYI, PYRO or NATEDOG or one of them already posted that they intend to have several "wing" configurations available for the Spit, your choice. That was the whole point in another thread trying to find historical markings of a unit that used several Spit types.
-
Actually Jochen, the Germans were behind in Hi-octane fuel development.
Maybe thats why they relied on water injection?
Then again there fuel injection system was way more advanced than the brits (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Redefining fuel? Sounds like a job for the beauracrats <- I cant spell either
------------------
Chisel
5./JG5 'Ice Bears'
[This message has been edited by chisel (edited 08-27-1999).]
-
Romanian and russian fields provided a lot of gas but it was just crude oil. Germany didn't have the infrastructure to redefine it.
That's one of the reasons why 190 was prefered aircraft later I think.. if i remember correctly radial BMW engine could run on less redefined gas then DB's...
As for Spitfire IX e or c, whatever (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif) It's still a beutiful HS cannon that will make a hole in your bellybutton (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Wait.. let me check out when the germans first made modificaton kits for 109's from 20mm to 30mm's blah blah blah few months ..blah blah blah... and bullets were HE not api.. blah blah blah...
Iddon's testing shows that 109G6 with MW50 is 10 mph too fast at 25k !!! nah nah nah nah
------------------
(http://www.raf303.org/banner.gif)
Bartlomiej Rajewski
S/L fd-ski Sq. 303 (Polish) "Kosciuszko" RAF
www.raf303.org (http://www.raf303.org)
-
One thing missing is the relative performance enhancement of each engine and its combination of water/methanol injection and various and sundry supercharging affects that comprise what we are calling WEP.
What % increase in HP and efficiency resulted from the application of WEP on the PW radial ? and was this different than the % change that upside-down watercooled thingy in the 109's got from WEP ?
I'll bet Pyro has some skeletons in the closet on this subject......
JHL
[This message has been edited by Thermo (edited 08-28-1999).]
-
You're right, I am missing something. I'm missing how I could be missing something on something that is missing, i.e. a released version.
------------------
Doug "Pyro" Balmos
HiTech Creations
-
BTW, I don't know what you mean by having skeletons in the closet on this subject, so feel free to elaborate. I'd much rather have someone ask me a pointed question than not and just make an assumption, whatever it happens to be about. I can't answer everything, but I don't and never have subscribed to the strategy of just telling people what they want to hear.
------------------
Doug "Pyro" Balmos
HiTech Creations
-
hmmm I don't know about that fd-ski, perhaps the 109G-6 of warbirds is a compromise between GM-1 and no GM-1? If so it's speed is right between a 109G with GM-1 and one without.
-
As for Spitfire IX e or c, whatever It's still a beutiful HS cannon that will make a hole in your ass
Yes but the 7.7 mm's instead of 12.7 mm's makes me only tickle (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Wait.. let me check out when the germans first made modificaton kits for 109's from 20mm to 30mm's blah blah blah few months ..blah blah blah... and bullets were HE not api.. blah blah blah...
I don't know about you but I would like to see planes and oncoming RPS as accurate as possible. If you do not want to contribute, well, what can I say?
My viewpoint might be little leaned towards Luftwaffe planes but I certainly do not little RAF planes either. I just happen to have more books and info about Bf 109 and Fw 190 than other planes.
If you spot inconsistency in my posts, please feel free to point them out. Constructive criticism is always welcome.
------------------
Obfr. jochen 'Stern von Afrika' 2./ Jagdgeschwader 27 'Afrika'
-
Another thing,
The more I try to find out about WEP on German planes, the more conflicting information I find.
-
...You're right, I am missing something. I'm missing how I could be missing something on something that is missing...
My head is still kinda spinning after reading that one.
With regards to this and the other post my gut feeling is that detailed engine performance data for WWII vintage aircraft engines must be difficult to find, and in some cases not available.
My assumption is that since the data is not available for some aircraft, there must be some guesswork as to the relative affect of WEP on that engines performance.
I wonder aloud if the effect of WEP on engine heatrate, (output/fuel consumption) is accounted for at all.
I guess that post came off sounding accusatory, it wasn't meant to be. I have alot of respect for Pyro and what he has accomplished. I'm just curious more than anything else.
(shrug)
JHL
-
a chat to an engine friend of mine reveals
putting higher octane in a lower octane rated engine=minimal difference
putting lower octane in a high octane rated engine = bang
to get the benifit of high octane your engine must be designed to run on it and this involves higher compression ratios be they engine or supercharger/turbocharger
i posted some time ago wep /none wep numbers for some selected engines and the fact that merlins gain power as they go higher (up to a point)due to a feature of thier supercharger design
on MW50 it was often stored in a huge drop tank under the belly of a 109..originally it wes jettisonable but on later models it was not (Irma Behalter tank i think is was called)using MW50 left a charecterisic black trail during use from a 109 due to the engine running rich...fuel use went through the roof and it was a sort of piston "reheat" or "afterburner" in that you got extra acceleration and power at massive fuel use.
on the fw190 it left a charecteristic white plume this time during use(condesation due to presure drop behind engine and over the wing)
from what i have unearthed so far it would appear the rocket firing fw190s had the MW50 system removed
it would also appear that rocket or under wing guns on 109s could not be fitted if GM1 was fitted..i would speculate that the containers(bottles?) ..no doubt presurised ..were in the wings but have not been able to find catergoric eveidence that this was so(or not).
it would also appear that the GM1 versions had lower compression than other versions (not verified/refuted yet)
walter krupinski states that his unit of 109s had "special engines" which while good at altitude with boost were hopeless at lower altitudes..i wonder if thats a 109 with GM1 he is talking about.
my overall impresion is bomber intercepters would use MW50 while fighter interceptors would use GM1 in the case of the 109.
in the case of the 190 rocket armed ones or underwing weapon enhanced ones they lost the mw50 while GM1 was tried but with very little success
in the case of supercharger gears the setting were "M" and "S" on the merlin 61.s..they could be an auto setting but sticking it in high ("S") did NOT give you more power necessarily, LESS in fact due to the extra work the engine had to do and the supercharger waste gate dumped the extra air to save the engine from blowing up.
the time to change gear was "when it made no difference" according to the manual and that was around 20000ft(assuming auto not selected)..if you changed too early the boost would drop as the extra work was done by the engine and any extra air was dumped over the side...too late and you would see the boost rise as the extra air was used to increase performance.
the merlin had automactic boost control and this meant that if the supercharger produced too much air ..it got dumped...as you got higher less air would be dumped and thrust horsepower is a function of true airspeed so as you got higher the engine could do more work and this meant the engine produced more power.
the DB(me109) engine had hydraulic supercharger control and worked similar to an automatic gearbox..as you got higher it "changed gear" (no gears infininatly varible)..increasing hydraulic presure increased the supercharger speed...but this took more horse power from the engine..the DB as fitted to the 109 could maintain is horse power up to about 20000ft and then fell off (unless boosted by an oxident such as GM1)
the standard merlin 61 gained power up to around 15000ft and then fell back to around 20000ft where the 2nd gear ratio now took over and power once more increased to around 30000ft and then fell off.
while the DB engine would have a flat power output up to 20000ft or so the merlin 61 would have two peaks around 15000ft and 30000ft
while MW50 would add 300-500hp the power line would remain similar up to 20000ft
if GM1 was used then it would still be the same but the extra power output would have more effect at higher attitude (thiner less air so less oxygen) becasue it is an oxident(GM1 contains oxygen).
the advantage of the super/turbo chargers is they dont run out while fuel additives do
the merlin on 27 liters capacity could put out 1700-1800hp at its peak without additives..the DB605 was around 1400-1500hp with some thing like 44 liters and the big motor in the thunderbolt got 2000-2000hp on a capacity you could put lake geneva in
think i'll go and plot some graphs on engine performance at various altitudes... (dont know if im a sad case or dedicated..hard to tell (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
have a nice day
Tomb
-
Hats off to tomb, excelent information! From where have you got all these tidbits? We need more posts like these.
Those white trails in Fw 190 would be neat. (hint hint, wink wink, say no more say no more (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) )
------------------
Obfr. jochen 'Stern von Afrika' 2./ Jagdgeschwader 27 'Afrika'
-
Thermo,
No prob, I'm just a little tired of some of the things I've been hearing. There is some good info on engine performance through various altitudes at different manifold pressures. This is not always the case though and you end up having to interpolate/extropolate a lot of data. That's not necessarily a bad thing though, because a lot of the information in the first case is probably interpolated/extropolated data anyway. This information can also be derived from performance analysis. The best results come from looking at the problem from multiple directions and trying to prove what is correct. If you take a single piece of data and base all your conclusions on that without doing anything further to verify its validity, you can end up with something not so good.
------------------
Doug "Pyro" Balmos
HiTech Creations
-
that information comes from various piston engine books...the best and most informative by bill gunston
Tomb