Fw 190D and Me 109K vs. Yak-3 and La-7

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Without MW-50 the 190D was around a 380 top speed fighter. To get close to that 426 mph top speed you'd have to push the teat as they say. Doing that most likely would be done only to evade, maybe catch up to a foe and not for dog fighting as your motor could go poof quicker than you think. Nothing worse than no power or fire in a dog fight. Contrary to the arm chair Sim pilots view that you can use WEP/over-boost all the time or until heat and/or the juice used up was normal operating procedure of the motor with no consequences; is a falsity.
 
 
I think Calum is, indeed our expert in here on engines, and I have two copies of his book. There's an Amazon story behind that one. Perhaps he IS "Snowy" about now, but I have seen NO evidence of the "grouch" part of his handle.

But, the Jumo 213F never flew in a production airplane that saw combat. So, if we include an engine that never saw combat as a candidate for anything that could be expected to occur during the war, we're in "what if" territory and not realistic territory. It's OK to speculate, to be sure, but then we're not talking about what realistically could happen during the real event using products that were actually developed into workable war materiel.

If we are being realistic, we'd propose things that maybe happened but were never well-exploited; not pure conjecture. Did they make a Jumo 2123F? Yes. But it never saw light of day deployed in an airplane on active duty and I never saw 2,900 hp reported. I HAVE seen 2,350 hp reported, with 2,450 hp being the target. Multiple instances of 2,350 hp being reported are likely quoting from the same source or article. The "never on active duty" part makes it a non-starter in my book, but it would have likely been a good one had it been produced.

I am a bit of an unbeliever when it comes to speculation on performance of an airframe with an engine that never saw production. I don't believe the XP-39 went 390 mph during flight test, but I have books that SAY it did. Methinks they are less than truthfully accurate, at least in the case of the XP-39. Perhaps the planned use of the Jumo 213F falls into the XP-39 performance mystery area, too, but I tend to have some faith in German performance calculations of piston airplanes. If performance was greatly exaggerated, it was likely to Hitler, not to service pilots. American, British, and German (as well as any other natilnality) slide rules all get the same answers.
 

But that was still over-boosting the motor over the normal 100% power. At 100% power that mill would still produce the 1726 hp as it would before the kit to increase the boost pressure and even that was not used 100% of the time. That's like saying the Merlin using 100-150 octane which could pull 72-80" of boost in emergencies and claim that as normal 100% power.

Comparing apples to apples is what needs to be done; no matter which country's aircraft tickles your fancy.
 

I'm not sure when over-boosting became a dirty word. Over-boosting was done on purpose, and it mattered. Just like the afterburing matters for decades now.
 
tomo pauk said:
I'm not sure when over-boosting became a dirty word. Over-boosting was done on purpose, and it mattered. Just like the afterburing matters for decades now.
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Not a dirty word, but a realistic word that means you are pushing the motor past the maximum power that it would normally operate and stay a functional engine. It's not a question of if, but when it will cause major problems that you won't like.

So if you're in a life or death situation, then of course you would use it as your life depended on it and you wouldn't care if the motor came apart. 99% of the time you would never abuse your motor with those high pressures and rpm's. They called those settings Emergency power of some type for a reason. For the Jumo 213 the settings were termed "increased emergency power" and "special emergency power"; now I wonder why that is?
 
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Good point, Tomo.

The afterburner DOES and HAS mattered, but it also doesn't tend to "blow up" a jet engine. The worst part of the afterburner is the speed with which the fuel gauge gets to empty, not the possibility you will crash from engine failure while there is still fuel.

Overboosting a big piston could be a non-event that just had to be logged, could be an engine change for the maintenance crew, or could be a nylon letdown ... and you could never tell when the last kind was coming down the pike. So, while WEP was certainly a resource, it also wasn't one you'd use without a very good reason to use it. Afterburner, on the other hand, is kind of normal for jet takeoffs. WEP is definitely not on the menu for piston takeoff.

I'm not saying we shouldn't know the performance at WEP power settings, I'm saying they didn't USE them very often, so the performance at normal or military power was used for the vast majority of piston combats. Like several WWII pilots have said to me, "maximum speed is somethign a test pilot discovered in a factory-fresh, clean airplane with a new prop, not something we used on missions." If you were at WEP, your wingman usually could not stay with you beacause he didn't have a power cushion to stay in formation when you turned away from him. Nobody wanted to lose a wingman in a combat zone and wind up with half the eyes looking around for an ambush. At least not very often. Many times, once was enough to kill you.
 
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tomo pauk said:
I'm not sure when over-boosting became a dirty word. Over-boosting was done on purpose, and it mattered. Just like the afterburing matters for decades now.
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One instance that has been put in writing about what using Special Emergency Power might cause.

"Czypionka admired both the Mosquito and its crews. "That airplane, it was so beautiful, it flew so well, I almost hated to have to try and shoot at it." In truth, the Nachtjagdgeschwader pilots had little success against the roaming Mosquitos. "They would send us off just before the British were to arrive. Our only hope was to get up to ten or eleven thousand meters and dive on them to catch them. If they were flying higher than eight or nine thousand meters, we had little chance, they were so fast."

The young Leutnant nearly killed himself in October 1944, attempting to get a Mosquito. "The controller put me right up in front of a group of them, and I had the altitude to dive on them. One was caught by the searchlights, and I went after him. I was diving on him and he was still almost as fast as I was - it was such a beautiful plane! - so I pushed the throttle into over-boost, into takeoff power. I knew the engine wasn't going to like it, but I wanted to get him."

Czypionka dove from eleven to seven thousand meters with the searchlights sticking to the wild-flying Mosquito. Finally, just as he was about to pull into range, "The searchlights lost him and there I was in the darkness. And then, before I could throttle back, the engine exploded!" Oil burst from the engine all over the windscreen, and the engine compartment caught fire. "I was going to bail right out," he recalls, "and I got rid of the hood, but then the wind blew out the fire in the engine. It was definitely dead, but I stuck with it a little longer. I got all my gear and disconnected everything. I was really calm, much moreso than I would have expected. I could see the altimeter read almost five thousand meters when I got up on the back of the canopy, just like they instructed us, and pushed myself up so I would miss the rudder. There I was, falling up into space, and it was so beautiful in the night." He counted through several seconds of free fall, until he estimated his altitude at five hundred meters, at which point he pulled the ripcord.
 
Different nations may have had different standards for over boost.

For the US the standard was that the engine, on a test stand, had to withstand the rated power for 7 1/2 hours, done 5 minutes at a time with 5 minute cool down periods between each 5 minute WEP run. That was the minimum. A manufacturer could choose to run the engine longer between cool down periods.
This would be a fresh engine and not one with dozens (or over a hundred) hours on it, except for standard testing hours.

SOme of these engines were rather sensitive as to the spark plugs used. There were often several different types approved for use but some spark plugs did better during overboost operations than others.

Even so, US practice was to put a tell tale wire across the throttle so the crew chief would know if WEP was used during the flight and extra maintenance procedures might be used.
More frequent plug changes were very common.
 

You are using data from the flight test campaign when the engine was limited to 1750hp. when the supercharger hadn't been improved and likely a few other issues with the airframe.

Speed was 408 mph with 1900hp, no MW50 needed. Increase power was just a boost increase that took power from 1750->1900.

Water injection "Special Emergency Power" took this to 426mph to 433 mph depending on condition of airframe and the type of MW50 system used (field retrofit blown in by supercharger or junkers fitted pumped in at high pressure). . The 1900 hp rating became indefinite while the 2100hp was 10 minutes continuous followed by a pause of 10 minutes (or latter 5).

I believe the WEP rating on the BMW801TS was increased to an unlimited period (so long as the emergency shall last) and the temperature warnings didn't exceed limits.

There is a myth that Emergency Power was only available for 3 minutes or so. Possibly originates with the early problems with the SABRE.

10-15 minutes would be more common. Unlimited would also be common.
 
mad_max said:
Not a dirty word, but a realistic word that means you are pushing the motor past the maximum power that it would normally operate and stay a functional engine. It's not a question of if, but when it will cause major problems that you won't like.
Click to expand...

War was not a time of 'normal'. So people that were making decisions have had no problem of allowing the engines in service to be pushed beyond the 'normal', for short time, and when it mattered. Some engines were better in this, some countries have had access to 'better' fuel than others, some manufacturers used ADI while some others did not. Everyone was trying to extract extra HP from their engines, results ranged between performance increase and blowing off the engines (and killing pilots/crewmen in worst case).


(my bold)
The bolded sentence covers a lot.
Jumo 213 have had no 'increased emergency power' - that was BMW 801D/E/S nomenclature (along with Notleistung). For Jumo 213, it was 'Notleistung' (emergency power) and 'Sondernotleistung' (special emergency power). Difference in power required difference in terminology.
 

Unlimited duration for Emergency power? Please, do tell, if possible without 'I believe' and 'possibly'.
 

I've personally in the past 40 years had chats with many (over 30) fighter pilots in the armed forces and most never used WEP in combat. The few that did use it said it was in desperation of usually trying to catch a fleeing enemy or in a non-combat situation to see what that extra power was like. All of them that were behind Merlins said they would operate at 61" of boost in combat though. Try as I might; I never got to have a chat with any German pilots to ask them the same questions.

Contrary to many I'll never accept that Emergency power was ever used over 5% of combat time. You just wouldn't do that to a motor that you need to have faith in to get you back on the ground without a silk ride.



I found this video that was enlightening to me. It's worth the 19 mins. to me.

 

I have never spoken in person with any combat pilots. Best I can do is read a host of combat reports noting use of over-boost in order to catch and kill enemy aircraft (= an actual, real thing why fighter aircraft existed and still exist).
German pilots were often very lucky if the engine was capable making the 'book' power at the 1st place, especially if the DB 605A, DB 603A or BMW 801 was under the hood.

I found this video that was enlightening to me. It's worth the 19 mins. to me.
Click to expand...

Thank you for the video.

After all is said and done, seems like there was reasoning behind all of those emergency ratings after all.
 

I'm relatively sure HP is PS in the figures your showing. 1750PS = 1726HP 1900PS = 1874HP. Yes I know not much difference and just wanting to be talking apples to apples, plus some on the forum might be new folks who wouldn't know the difference.

As for all motors a boost increase will raise power. On the Jumo 213 (most German engines from what I've read) to get this boost increase they used increased rpm of the motor which of course would increase the boost. They used every ounce of pressure the supercharger would provide at a given rpm and the only way increase boost on the 213A was by using 3250 rpm. In later model Jumo's they added superchargers that would deliver higher pressures without increasing rpm, but none of those saw combat in the 190D.

The US didn't increase the rpm usually to make more boost pressure; but could set up the over-boost protection system that protects the pilot from blowing up his engine, to use the unused boost from the super-charger or turbo. From experience in auto motors you can cause damage from either, but I'd rather add boost only and not push the rpms up. A small displacement motor eats rpm right up. A large displacement motor; no matter if auto, aircraft, etc., doesn't appreciate high rpms very much. The Jumo 213 is a heck of a huge motor with a longer stroke and with lots of weight being thrown around while it's operating.

Which way would be the best to raise boost without causing other problems is another question. I imagine I'd rather have a smaller motor turning 3000 rpm with increased boost than a larger motor with higher rpm to get that higher boost. Just saying.


I'd have to see documents that state that 1900 PS was normal operating power indefinitely. See my other post with the youtube video) on Power of the Jumo 213.
 
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Yes I've seen those pilot reports and just like pilot stories told; they were what the pilot "remembers" at the time he was engaged in catching, shooting or getting shot down. Those stories even include using 75" of boost in the merlin and British pilot reports state they were using 80" of boost.

So we can believe the pilot stories about exceeding the sound barrier with a prop plane? How about coming home on a jug or two missing? The the one where a pilot said his motor was running rough after a combat sortie, then later his mechanic told him a connecting rod exploded and there was just a bunch of metal pieces in the crankcase?

tomo pauk said:
After all is said and done, seems like there was reasoning behind all of those emergency ratings after all.
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I posted that Emergency power was used in times of need; such as closing the gap on a foe, evading or escaping a bad situation any time you were in a desperate situation. I guess I wasn't clear enough. Have you seen any pilot notes that said the foe and me were doing combat maneuvers and I used emergency power while doing it. I ask Bud Anderson what he mean't by pushing the throttle to full power in his story about the one foe at high altitude. His reply; full power mean't 100% power and that is I asked. The answer was 61".

So as I said and I believe it's the proper answer. 99% of flight time in combat was at nominal power and 1% was at emergency powers.
 

You are comparing apples and oranges - pilot reports (= official documents) vs. war stories.


I've heard you before.
Please refer to dozens of combat reports that cover use of over-boosting, starting from BoB-era reports where pilots reported the throttle lever pushed 'through the gate' - boost over +6.25 psi - with Merlin III under the hood.

So as I said and I believe it's the proper answer. 99% of flight time in combat was at nominal power and 1% was at emergency powers.
Click to expand...

Okay.
 
When Jeffrey Quill reported back to Supermarine after his stint of combat during the Battle of Britain, he said on patrols and normal operational work the squadron pilots always treated their engines with the utmost care and respect -- but when combat was joined they paid no attention to any limitations and taxed the engines to the full.
 
Well i think every skilled pilot have avoided using WEP except life saving measures - WEP it was and still is available in military powerplants as a real "red line" measure. Pilot may use it but he must realizing that price will be almost instant damage to the engine. I talked with former ground crew chief of 131 PAF fighter wing and he told me that Merlins have been ever replaced after overboost usage was reported by pilot - not very affordable situation with limited supply of replacement engines.
 
I am currently putting all the performance information I have on WW2 fighters
on Excel. This thread has stirred up my curiosity on the Fw 190 past what I have
in my files. Tonight I came across a 3 x 5 index card with the following information
concerning the Fw 190D-11.
Gen. Qu 6 Abt.aircraft distribution plans March 1945.
Thirteen "standard" D-11s & four D-11s with the EZ 42 gun sight were delivered
to operational units. It is possible that a few more were delivered in April 1945.
Production Fw 190D-11 fighters are known to have been issued to Stab JG 300
(Kommodore Major Rall). II/JG 300 (Major Baier) and the JV 44 Protection Staffel
("Wurgerstaffel") under Lt. Sacksen Berg.
Wing roots: 2 x MG 151, Outer wing: 2 x MK 108.
Jumo 213F: 2050 PS with MW 50

I remember this as being on an official distribution report but can't remember the
particulars. Anyone have more information on this?

PS: The reason I am asking is that I have some graphs and charts on the D-11 and
am planning on adding them to Excel IF the information above is accurate. I am only
adding the performance of fighter aircraft that were actually in combat.
 
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