Suggested, complete Spitfire lineup for Aces High

[HoHun]

Hi Butch,

>Hohun so far i haven't seen any proof of a late type supercharger being used on The Aa, even the in late 1939 documents i have.

Thanks, that's an interesting information to keep in mind for the analysis of the Yugoslavian data.

Technologically, if early/late type superchargers can be swapped freely with the DB601A-1, the same should be true for the DB601Aa, though.

Regards,

Henning (HoHun)

[Kurfürst]

Originally posted by butch2k
Isegrim the latest chart is for an a/c equipped with the DB601 Aa engine, the later manual clearly stating that the 1.45ata setting is for "abflug" only, just the same as the DB 601A-1.

[/B]

Regardless, it shows the maximum performance that could excepted from DB 601Aa powered 109E-3.

And, to be more precise, the power curves for DB 601A-1 show that`s it`s usable in only the first supercharger speed (up to 1.6km altitude with the old type supercharger, and up to 2.1km with the new 4.5 km supercharger). Not strictly for takeoff, but for relatively low altitudes.

http://www.onpoi.net/ah/pics/users/503_1120078359_db601aearlycurve.jpg

That`s from 0 to 6800 ft in static/climb conditions, and about up to 3km or 9000 ft in speed conditions. That`s quite an altitude range, similiar to the practical power boost achieved with +12lbs emergency boost on Merlins.

Basically :

a, The 1.4/1.45ata boost was present on DB 601A/Aa engines
b, As you say, about 30% of the Luftwaffe`s Emils had the Aa engines
c, Nothing prevented the pilot from using it.

So he used it if he wanted, but of course he didn`t neccesary had to.

Those setting were no combat settings at all, and the several DB 601A (-1/a) manuals i own clearly state that it should be used only if really necessary as it put a lot of strain on the engine.[/B]

Butch, basically all German manuals mention that the highest power should be used 'only if neccesary because puts great strain on the engine etc'. 601E, 605A manual mentions the same, it`s a common formula for War Emergency Power, not only in Germany but also in US or the RAF.

Ie. in regards of +12 boost, they warned the pilots not to use it unless neccesary because of the overload :

[IMG]http://www.spitfireperformance.com/dowding1.jpg

It`s all similiar, it calls it 'emergency boost' and to be used only when 'circumstances demand it'. It overstrains the engine, just like on the DB. Same thing.

I guess an enemy fighter on the tail counts as such 'neccesity' or 'circumstance'. There was absolutely nothing that prevented the pilot from using it when he needed it.  

I would not consider them for comparison since their use was limited to very specific cases, like taking off heavily burdened. [/B]

I`d agree that it was generally not used. It`s nothing specific about the 601`s WEP, pilots engaged WEP on very rare occasions when they were in trouble. Nowadays people develop the idea that everybody was contsantly whacking the engine by running on maximal power - it`s just so untypical for real life! But when it was neccesary, it could be used.

Personally, I find it strange to include in a comparison the RAF`s special low altitude boost that required high grade fuel and was gradually introduced during the BoB, and NOT to include the special low altitude boost that was present on ALL Emils... it`s the kind of double standard that repeated and plagues the credibility of those comparision articles from MW/NS.

[butch2k]

FYI

[HoHun]

Hi Butch,

>

Thanks for that! :-)

I'll translate:

---cut--------

Power Increase for Departure (Permissible Duration 1 min)

By pushing the throttle lever beyond the "Full Power" position - without pausing - up to the stop "Departure".

Holding the lever in the "Departure" position is not permitted since it's pointless, instead, the lever is to be re-set to the "Full Power" position again. The clockwork that has been wound by pushing forward the lever terminates the boost increase independendly of the lever position after 1 minute. Holding the lever in position "Departure" would not prolong the boost inrease or refresh it, but merely result in a continued fuel enrichment - meaning an increase of the fuel consumption without a power increase.

---cut--------

Do we have any evidence on the use of the "Departure" setting in the Bf 109 at all? I think I have an old "Flugzeug" issue somewhere that quotes the clockwork regulator a requirement for the use of Departure power.

(I'd compare Bf 109 and Spitfire on corresponding power settings, 30 min power vs. 30 min power and 5 min power vs. 5 min power. A 1 min power setting, even if available in combat, would appear only like a small advantage to me.)

Regards,

Henning (HoHun)

[Kurfürst]

Thanks butch for posting it. But I have to point out, reading the text and HoHun`s translation, there`s absolutely nothingin it that would prevent the pilot from using the 1-min 'Erhohte Kurzleistung' if he wanted, provided he was flying at lower altitudes. OTOH, it`s nice evidence to the existance of the boost system, but I fear it will be looked over.

The fact that the type of WEP was primary intended for takeoff at heavy loads has nothing to do with the possibilty. He can operate it at any time he sees neccesary, by pushing the lever forward and the system automatically resets after 1min.

HoHun is very sensible in that comparisions are to be made at similiar settings. Currenltly, its not done, the articles compare the 109E and G on 30 min power to the Spitfire on 5min power.
However, if there`s a system that was found on only one of the planes, it cannot be ignored on the basis the other doesn`t have. You cannot exclude GM-1 for istance (MW/NS does though) on the basis that it was only employed in the LW.

Actual usage is muddy water. How many pilots used the 1-min WEP? How many used +12lbs overboost? Certainly not all of them, every time.Certainly not every pilot pushed the aircraft to it`s limits, but that does not re-define the absolute limits the a/c is capable of.

[MiloMorai]

Originally posted by Kurfürst
Regardless, it shows the maximum performance that could excepted from DB 601Aa powered 109E-3.

for one (1) minute only  while the Spit could do it for five (5) minutes.

That`s from 0 to 6800 ft in static/climb conditions, and about up to 3km or 9000 ft in speed conditions. That`s quite an altitude range, similiar to the practical power boost achieved with +12lbs emergency boost on Merlins.

could the E-3 reach that altitude in 1 minute? It took ~3 minutes to reach 3 km

Butch, basically all German manuals mention that the highest power should be used 'only if neccesary because puts great strain on the engine etc'. 601E, 605A manual mentions the same, it`s a common formula for War Emergency Power, not only in Germany but also in US or the RAF.

for one (1) minute only  while the Spit could do it for five (5) minutes.

Ie. in regards of +12 boost, they warned the pilots not to use it unless neccesary because of the overload :

[IMG]http://www.spitfireperformance.com/dowding1.jpg

Why did you not post a link to page 2?

It`s all similiar, it calls it 'emergency boost' and to be used only when 'circumstances demand it'. It overstrains the engine, just like on the DB. Same thing.

That is why the DB was restricted to 5 minutes at 1.30 and 1 minute at 1.45

Personally, I find it strange to include in a comparison the RAF`s special low altitude boost that required high grade fuel and was gradually introduced during the BoB, and NOT to include the special low altitude boost that was present on ALL Emils... it`s the kind of double standard that repeated and plagues the credibility of those comparision articles from MW/NS.

and the N motor required special/high grade fuel, C3, which according to Radinger/Schick was not readily available.

LOL Kurfy. You talk about credibility, you the grand master at data manipulation, selective quotes/facts, etc, ect, ect...

[MiloMorai]

Originally posted by Kurfürst
HoHun is very sensible in that comparisions are to be made at similiar settings. Currenltly, its not done, the articles compare the 109E and G on 30 min power to the Spitfire on 5min power.

IT does?



Notice there is a line for the Spit at 12lb and one for the 109E-1 (notice also that the 109 type is specificaly mentioned) at 1.33 which was restriced to 5 minutes.

[Crumpp]

for one (1) minute only while the Spit could do it for five (5) minutes.

Hey Milo,

The Merlin did not start out with (+12) boost for 5 minutes.  The limit was increased over time.  This is normal for most engine boost progression.



What I do see after listening to the 109 Experts is still a questionable comparison.  It attempts to deal in absolutes with a subject which has no absolutes.

Some facts to consider, the new boost setting appears to required cylinder head modification and/or new piston rings so it seems highly unlikely the conversion happened overnight.

The RAF had received roughly 400 Spitfires, according to Shacklady and Morgan, along with the well over 1000 Hurricanes without the modification before the order was issued.

A total of 1,715 Hurricanes flew with Fighter Command during the period of the Battle, far in excess of all other British fighters combined.

http://www.raf.mod.uk/bob1940/hurricane.html

These would have been torn down and modified.  A time consuming job.  The parts have to be available as well.

Now the maintenance may not seem like such a big deal but keep in mind that the RAF was at war.  They had to maintain operational readiness.  This is why it appears that the RAF ordered the modifications to be done during normal scheduled maintenance of the engine.  Seems a logical way to handle such a maintenance/operational issue.

New production engines came with the modification.

http://www.spitfireperformance.com/ap1590b.jpg

So while I tend not to believe the "overnight and immediate introduction" I also do not believe the "snails pace" theory either.  It was most likely somewhere in the middle with the majority of RAF fighters using the modification by the BoB's end in late 1940.  Anybody have a maintenance scheduale of the number of hours a Merlin flew before overhaul?

 

A total of 1,715 Hurricanes flew with Fighter Command during the period of the Battle, far in excess of all other British fighters combined.

Just as the Luftwaffe was introducing more powerful engines for the 109E series, the RAF was increasing the power output of the Spitfire.  As can be seen from the Yugoslavian export variant 109E (DB601Aa), some 109E performance did match/exceed the (+12) boost Merlin Spitfire.  So what we have in both air forces is an ever-growing pool of better performing fighters?  

Some Spitfires are superior to Some 109's and vice versa.  Never is it all Spitfires are superior to all 109's or reverse.

Yugoslavian export version 109E climb:



All the best,

Crumpp

[MiloMorai]

Crumpp,

I guess you missed the image posted that had the 601 still limited to 1.40/5 ata for 1 minute in 1942.

During BoB, 12 lb was good for 5 minutes. (see ref 16, the one Kurfy would not post)

The Merlin XII was a Spit II engine. You give no date for the image. The emergency of BoB had passed.

I noted in a previous post that parts would be a restriction on conversion, not the availablity of 100 fuel, of which there lots of stock. Remember though that 11 Group was the Group that faced the Germans the most and would have preference for any converted Spits.

Using the 5 minute limit for both a/c, which the graph shows, is a fair comparison.  Using the 1 minute at 1.40/5 for the 109 is not, but could be included as a comparison to satisfy Kurfy in his quest to have the 109 the uber a/c.

If Mike had only used a genaric designation, ie 109E, then Kurfy would have a reason for his crocidile tears and have to use a life vest. Do really expect Mike to be nice and include other models after Kurfy's character assination and slandering of him all over the net?

As a side note, RR was experimenting with water injection in 1938, but was relegated to a 'B' priority.

[Crumpp]

I guess you missed the image posted that had the 601 still limited to 1.40/5 ata for 1 minute in 1942.

Hey Milo,

I did not miss that image.  In 1942 the development of the 109E was at a standstill as it was being replaced.  Its replacement entered service in early summer, 1941.  Something else to consider is that many manuals regurgitate older information or rely on technical orders.  For example, you won't find the operation/installation/maintenance of MW-50 in any FW-190 manual.  That is contained in technical orders seperate from the Flugzeug-handbuchs.

The POH is dated Jul 40.  Do you know the differences between these Merlins?

If Mike had only used a genaric designation, ie 109E, then Kurfy would have a reason for his crocidile tears and have to use a life vest. Do really expect Mike to be nice and include other models after Kurfy's character assination and slandering of him all over the net?

No I would expect Mike to see that kind of behavior for what it is as most of us do.  I would not expect Mike to "retaliate" in kind and stoop to that level.  Especially when it creates a false impression.  While his comparison may involve two particular Bf-109E's, for which little setup information is posted, the impression created is an attempt at a broad spectrum analysis that is just not true.

The percentage of these aircraft at the front is debatable.  The fact they were operational contemporaries is not.

All the best,

Crumpp

[Kev367th]

Merlin II - 1030hp Fitted to Ia (1537 made.) and Ib (30 made)

Merlin XII - 1175hp Fitted to IIa (750 made) and IIb (170 made)
Increased speed by approx 10mph+ over the Merlin II.
First delivered to the RAF June 3rd 1940

From BoB
The Mk I Spitfire was to continue service throughout the Battle of Britain, and was a worthy opponent of its German equivalent, the Messerschmitt Me 109. But in August 1940, at the height of the battle, the Spitfire Mk I gave way to a faster and more powerful Mk II with its Merlin Mk XII power plant. Most of these MK II's were to arrive after the Battle of Britain, although some squadrons had been allocated them in late August and during September 1940. The first recorded Mk II being shot down was with 611 Squadron on September 11th 1940.

[MiloMorai]

Crumpp,

Might be your impression but I don't see it that way.

Did Mike get a thank you when he made corrections? Nope, only more slander and ridicule.

What does it matter if the E was at a standstill in 42 for the 1.40/5 time limit had not been raised even when it was in service.

[1K3]

(off topic but...)

Our spitfire mk I does run +12 boost at WEP.

[Nashwan]

Are you sure it does?

I tested the Spit I not long after AH II came out. It said 12lbs on the boost gauge, and the fuel consumption was correct for 12 lbs. But it was 15 - 20 mph too slow at low level, and didn't climb anywhere near well enough for 12 lbs.

IIRC, it was somewhere between 6.25 lbs and 9lbs in performance, with fuel consumption equal to 12 lbs.

Might have changed since then, of course.

[Crumpp]

Might be your impression but I don't see it that way.

It is my impression and you are entitled to yours.  

All the best,

Crumpp