Production rate versus type effectiveness

[Vincenzo]

Price in currency doesn't mean a great deal in a country that is bankrupt.

The numbers don't seem right anyway. The actual price paid for a Mk I Spitfire in 1940 was £6033, which works out as around 75000RM.

AFAIK 1941 exchange rate pound:RM was near 1:80 (crossing with US $, obv. wasn't a exchange rate form pound and RM)

 

[red admiral]

AFAIK 1941 exchange rate pound:RM was near 1:80 (crossing with US $, obv. wasn't a exchange rate form pound and RM)

Its challenging to get figures that are anywhere near accurate for a wartime period, especially when one country is practically bankrupt. The exchange rate I used was 1:5 for £ -> $ and then 1:2.5 for $ -> RM from 1940.

 

[Vincenzo]

Its challenging to get figures that are anywhere near accurate for a wartime period, especially when one country is practically bankrupt. The exchange rate I used was 1:5 for £ -> $ and then 1:2.5 for $ -> RM from 1940.

the crossing exchange for 1940 it's near 1:10 (pound:us$ 1:4) but my intention was only give a idea that the exchange of 1943 (maybe need crossing with switzerland franc) have a small relations with 1940 exchange

 

[drgondog]

Its challenging to get figures that are anywhere near accurate for a wartime period, especially when one country is practically bankrupt. The exchange rate I used was 1:5 for £ -> $ and then 1:2.5 for $ -> RM from 1940.

As mentioned earlier, the labor hours and Relative cost of Government Furnished equipment is a better Rule of Thumb' for a first cut production evaluation.

Raw material 'relativeness' is another increment - and scales as a function of weight until exotic or hard to acquire materials are factored in (i.e Jumo Turbine blades).

Large orders are crucial to assembly line/manufacturing planning because it is easier to absorb cost of jigs/fixtures and better configure shop floor layout when you know you will be making a lot of that particular airframe.

 

[drgondog]

But who has the man-hours available for a wingtip to wingtip of the 109,the 190, the 51, and the Spit 9?

As noted before the labor hors for the P-51A was 12,000 and the labor hours for the P-51D/K at the end of the Production was 2077 hours. A steep labor learning curve as well as well planned manufacturing tooling and processes

 

[renrich]

Here is some interesting info from a book of mine about the Hellcat production. "The Navy went on record saying that Grumman produced more pounds of airframe per taxpayer dollars than any other company in the fighter business." The Hellcat original price was $50000 exclusive of Government Furnished Equipment. By the end of the production run the price had been cut to $35000. There was a contest between Grumman and North American(building P51s) and when in March of 1945 Grumman set a record and beat NA, the news was announced over loudspeakers in the factory.

 

[drgondog]

Here is some interesting info from a book of mine about the Hellcat production. "The Navy went on record saying that Grumman produced more pounds of airframe per taxpayer dollars than any other company in the fighter business." The Hellcat original price was $50000 exclusive of Government Furnished Equipment. By the end of the production run the price had been cut to $35000. There was a contest between Grumman and North American(building P51s) and when in March of 1945 Grumman set a record and beat NA, the news was announced over loudspeakers in the factory.

Ren - that claim would be true if in fact the integration of unit cost per airframe from start to finish of the production cylce is calculated. What I hear is that at the end of the cycle in March 45 the Hellcat was less expensive - same hold true for December 43 or November 1945?

Another possible question is adding cost of AT-6 and B-25 as well as F4 and F7 to see whether Grumman produced more pounds of airframe per taxpayer dollar - or just talking about F6F. The addition of the F7F to the equation would take the taxpayer dollar up per pound because so few were built - similar to the new tooling and low production for the P-51H and no deliverered P-82's..

I was 'in' Guv accounting for some time and have a healthy respect for artful lying on part of Contractors relative to true costs/charges and write offs.

Anyway that is interesting on final airframe cost - what was F6F 'all in' unit cost in March 1945? Sounds like it was still less expensive.

 

[renrich]

Bill, note that the quote from the Navy specified " any company in the fighter business." I guess they were not including anything except Hellcats, Mustangs, etc. In March, 1945, Grumman produced 605 Hellcats. They don't give anymore figures than the $35000 at the end of the production run. Grumman also set marks for low absenteeism and turnover in the aircraft industry. All of this is from the "Great Book of WW2 Aircraft," and I am getting a hernia from picking the dad gum book up it is so big and heavy.

 

[Burmese Bandit]

A rough calculation from me:

Man-hours per fighter at BEST rate of production...

about 2,000 for a 109 G
about 3,000 for a late A-series FW 190
about 2,000 for a P-51 K
*nothing yet for a spit...

Would most here agree?

 

[Hop]

"..It has been reported that the Bf 109 took one-third the man hours to construct as the Spitfire..."

There are 3 problems in comparing aircraft.

First, money is not a good basis for comparison. Slaves don't need to be paid. Raw materials might cost more if they have to be shipped in from the other side of the world, less if they are available domestically. Exchange rates vary.

Second, what is an aircraft? The airframe? The airframe with engine etc fitted? Do you count the hours to build the engine as well as fit it? You have to be sure that the same standard is applied to all the aircraft you are comparing.

Third, you have to look at the time the figures are taken from. There are several examples in this thread that show how the number of man hours required to make an aircraft fell during the war. Sebastian Richie in Industry and Airpower gives some examples for the UK, eg the number of man hours to produce the Lancaster airframe fell from 51,000 in 1941 to 20,000 in 1945.

The "one-third man hours" for the 109 falls in to this category. It's based on a January 1940 figure for the Spitfire of 15,000 man hours, compared to a 1942 figure for the 109. (bear in mind the 109 was an older design than the Spitfire and entered production earlier, so it was further along in the process.)

I believe the Germans prepared a report in 1941 saying that the 109 cost 15,000 RM to build, and that the Spitfire, if built in Germany, would cost 12,500 RM.

 

[delcyros]

I believe the Germans prepared a report in 1941 saying that the 109 cost 15,000 RM to build, and that the Spitfire, if built in Germany, would cost 12,500 RM.

That would be particularely interesting, Hop. Can You quote or link the report?

 

[Kurfürst]

The "one-third man hours" for the 109 falls in to this category. It's based on a January 1940 figure for the Spitfire of 15,000 man hours, compared to a 1942 figure for the 109.

Did you miss the table I posted..?

Actually the 1942 figure for the Regensburger 109 would be ca. 3400 hours, one-fifth the figure than that of the Spitfire; thats for the 109G, and a new airframe type.

The comparable figure for an 1940 Spitfire (15,000 man hours) would be 5400 labour hours for the 300th Bf 109E produced in Messerschmitt Regensburg; this even gives some advantage to the Spit, since the Emil was a new airframe, and Regensburg produced very few of it by the time (ca 300, I am quite sure that there were a lot more Spitfires built by that time), and Regensburg's workers would be still somewhat unfamiliar with the type and at the beginning of the learning curve.

(bear in mind the 109 was an older design than the Spitfire and entered production earlier, so it was further along in the process.)

It was a better design when it came to series production requirements, but it was hardly older - the redesigned it with the 109E, then a major redesign came with the 109F (that itself was designed in 1939/40, years after the original Spitfire, and was the basis of most 109s built), and some modifications with the 109G and a redesign again with the K.

This shows in the table, the 500th example of the 109F series initially took some 50% longer time to complete than the 300th 109E, then it fall down to about 2/3s of the 109E with the 700th airframe. Then the same with the 109G, intitial man hours were longer, because the workers had to re-learn some of the process.

In contrast, Spitfire factories produced pretty much the same airframe throughout the war, with the same solutions. The biggest 'redesign' was replacing dome rivets with flush rivets on the fuselage.

 

[Hop]

That would be particularely interesting, Hop. Can You quote or link the report?

Sadly no, I've only got a reference to it from someone else. Kurfurst has referenced it, and looking at the page he posted, that might be part of it. I can't speak German, though, so I'm not sure.

In contrast, Spitfire factories produced pretty much the same airframe throughout the war, with the same solutions. The biggest 'redesign' was replacing dome rivets with flush rivets on the fuselage.

No.

The Spitfire I took 330,000 man hours to design. The more involved of the subsequent marks:

III - 91,000 man hours
V - 90,000
IX - 44,000
VII - 86,000
VIII - 25,000
21 - 165,000

In total the man hours spent on design were 330,000 on the Spitfire I, 620,000 on the subsequent marks.

As an example of the economies achieved in manufacturing, the Spitfire Vc wing required 400 less man hours to make than the Vb wing.

 

[Kurfürst]

These are interesting figures, where are they from?

Though looking at the figures its IMHO quite clear how little meaningful development was going on.. (take a look at the Mk 21 and compare it to the Mk IX - the former actually introduced a new wing structure, the latter only modifications needed to mount a new engine in the existing Mk V airframe)

I think I saw some figures for the development of the 109F in Ishoven's book, I will try to dig it up.

PS: The page I posted come from a book on German industry, iirc reference to the German report was made by George Hopp over LEMB.

 

[Burmese Bandit]

So then ... the figures now explain why the Germans continued to produce the 109 until the very end of the War...

BECAUSE it was so CHEAP and FAST TO BUILD and yet STILL EFFECTIVE...if you could get past some of her vices..

I have an idea for a much improved 109 with only slight modifications, but this rests on a premise that perhaps is mistaken:

We know that it was not possible to put MG 151/20 in the wing roots because of space and strength limitations. But would it have been possible to put MG 131s instead?

If so...here is an idea for an armament improved 109...

Put ONE, not two, MG 151./20 on top of the cowling. Only one cannon will make no ugly and speed and vision reducing bulges.

Put another firing through the spinner.

Put one 131 in each wing root.

Put a slim, streamlined belly pack mating with and enclosing the oil cooler in the nose, with a 131 on each side. The exhaust of the oil cooler will go through a tunnel in the middle of the pack, and exit behind the pack. Flaps for the oil cooler will be at the back of the pack.

Result: a 109 with the minimum of modifications, but with TWO 20 mm cannon and FOUR heavy machine guns - DOUBLE the firepower of the early Gustavs - without the need to have guns mounted in pods under the wings, which made the 'Kanonen boot' Gustav stiff and slow-rolling.

 

[Kurfürst]

BECAUSE it was so CHEAP and FAST TO BUILD and yet STILL EFFECTIVE...if you could get past some of her vices..

Yes indeed, it was a simple and effective fighting machine, which was also easy to produce and service in the field.

If so...here is an idea for an armament improved 109...

This is a bit off topic, but it was possible to mount MG 151/20s inside the wings with 100 rpg (or an MK 108 w 40 rpg), outside the propller arc, see late K-6 and later. On the other hand, everything I have seen shows that the installation inside the wing installation would be not very different weight-wise than that of the gondolas (mounting two MG 151s in the wings of the 190A came with practically the same weight as two MG 151s in gondolas on the 109G, roughly 130-135 kg w/o ammo), and the drag would not be much different either, ie. gondolas came with just 8 km/h reduction in speed at speed level on the early Gustav, while internal cannons of the - albeit much faster, so drag is likely even less at comparable speed - 109K-6 came with 5 km/h speed penalty at SL.. so gondolas seem to me as more practical - no change in wing construction, and they could be added and removed with ease, and the difference in performance between internal and gondola cannons is too marginal.

The wing root seems problematic because of the undercarriage, and so is fitting MG 151s on the cowling. The *might* fit, but it would require a much enlarged cowling etc, and the problem is there is very little space for their breech them between the engine and the cocpit panel.

 

[Burmese Bandit]

Yes, I'm aware of the ease of gondolas, K. What turns me against the gondolas is the 'pendulum effect' of the inertia of weight put so far outboard of the wings, which made the G-series with the wing guns so slow in the roll. Speed suffered only slightly.

The proposal is for only ONE 20 mm cannon, on the very top of the cowling, and if the breech of a 20 mm cannon can fit behind the engine in the spinner gun it should be possible to fit the 20 mm cannon just on top of the engine...

And what's your opinion on the belly gun pack proposition?

 

[Juha]

Hello Burmese Bandit
Re your post # 16

Source is Hannu Valtonen's Messerschmitt Bf 109 ja Saksan sotatalous, p. 274. And his source has been Groehler, p. 496, and Valtonen notes that the table is a rough approximation. Is the table from Olaf Groehler's Geschichte des Luftkrieges 1910 bis 1980 or his Bombenkrieg gegen Deutschland isn't clear.

Juha

 

[fly boy]

all i know is the average to make f6fs in a day is about 20

 

[drgondog]

Yes, I'm aware of the ease of gondolas, K. What turns me against the gondolas is the 'pendulum effect' of the inertia of weight put so far outboard of the wings, which made the G-series with the wing guns so slow in the roll. Speed suffered only slightly.

I haven't seen any data but the addition of ammo and guns outboard of landing gear would probably be on the order of a couple of degrees per sec roll rate degradation. Same internally or with gondolas.