Use of 150 octane fuel in the Merlin (Xylidine additive etc etc)

In article , Gregory W
Shaw writes
Others have already hit on what effect higher octane ratings had. Peter
Stickney will probably have one of his great replies coming along soon
too. But here is a quick rundown on what 104/150 octane should provide
for a Merlin 266.

SNIP of great summary of relevant formulae

Thanks, Greg - that is a really handy ready-reckoner.

Much appreciated!

Cheers,

Dave

--
Dave Eadsforth

In article , Emmanuel.Gustin
writes
Dave Eadsforth wrote:

: Yes, the success of agents like 'Garbo' in feeding duff stuff to the
: German High Command was remarkable.

The familiar problem, as far as I know:
Too many different intelligence services, every
one a part of the personal empire of a different
Nazi leader, and unwilling or unable to cooperate.
And of course the 'Abwehr' leaked like a sieve.

The Germans did produce recce versions of fighters,
usually with fewer guns and more fuel; in addition
to cameras of course. But I suspect the Bf 109 was
just less adaptable to the task than the Spitfire.
It was even smaller.

The Spitfire had inherited a D-shaped leading edge
structure from its direct ancestor, the Supermarine
227, which used this as a condensor for its
steam-cooled Goshawk engine. This made a great fuel
tank for the long-range reconnaissance versions.
With better fuel and more powerful engines, these
models could also operate at higher weights and
reach higher altitudes than Bf 109s.

On the other hand Ju 88s were less suitable for
reconnaissance than Mosquitoes, because they were
bigger and slower. Still, the Germans did develop
a high-performance recce aircraft in the Ar 234A.

Emmanuel Gustin

Thanks for that!

Re. the Ar 234A, I believe that this machine made a number of attacks on
the UK, but I do not know when. Do you happen to have any rough dates?

Also, do you happen to know if the Ar 234 (of any mark) was ever used as
a recce machine over the UK prior to D-Day?

Cheers,

Dave

--
Dave Eadsforth

Dave Eadsforth wrote in message ...
In article , The
Enlightenment writes
Dave Eadsforth wrote in message
news:s9BISHBVA3GAFw82
...
In article , WaltBJ
writes
Slightly off track - the Germans did not seem to place the same level
of importance on recce that the Brits and USAF did. Me109s could (some
did) carry a camera in the aft fuselage like the recce P51s (F6?). A
lightened waxed Me109F or G would have a very good chance of
completing a recce pass on an in-and-out basis flown at max speed on a
curving descent or in-and-out at naught feet (prop tips above the wave
tips). It appears to me that the 86R was declared a 'clay pigeon' when
the LW found out Spits and Mosquitoes, appropriately modifed, could
get up that high. Why the LW didn't use 'hot-rodded' photofighters is
beyond me. Maybe they swallowed the 'XX' turned spies' reports as
gospel.
Walt BJ

Yes, the success of agents like 'Garbo' in feeding duff stuff to the
German High Command was remarkable.

Without wanting to go wildly off-topic, there was a programme on UK TV a
few nights ago ('Spitfire Ace') that had some very useful stuff on the
mentality of the RAF versus the that of Luftwaffe in 1940. The RAF
(through the vision and efforts of Dowding) had created a parless air
defence system, while the Luftwaffe had concentrated overmuch on the
lionisation of its individual pilots.

Honestly this sounds like Brits patting themselves on the back while
not looking at the strategic and tactical issues the Germans faced.
(sadly this is a sort of anasthetic as the UK goes down a sewer)

While I agree that we, as a nation, should be organising our lives
better these days, there is no doubt that the British air defence system
of 1940 was unmatched anywhere else in the world, and no-one, not even
the Germans, dare to claim that Goering's boasts of 1940 held water.

The Britsh radar at the time was inferior. It used a laege omni
direction arial at about 10 years waverlenth wid radio direction
finding loops. the German Freya searh radars and Wurzburk radars were
at this time mobile, more accurate. They were too goog in that they
**** caned their micrwave developement on the basis that their radars
were more than good enough.

However as far as a system goes you are right. The Germans lacked IFF
(indentifiucation fried or foe) untill "erstling" came along and they
did not integrate the air defenses. Luftwaffe, Army, Navy and various
regions simply were not integrated properly and respnded with
confusion to a raid.

http://www.fas.org/man/dod-101/ops/docs/97-0609F.pdf:
DEFLATING BRITISH RADAR MYTHS OF WORLD WAR II
A Research Paper
Presented To
The Research Department
Air Command and Staff College
In Partial Fulfillment of the Graduation Requirements of ACSC
by Maj. Gregory C. Clark
March 1997



I think that by 1944 the Allies
had developed a war machine that was thorough enough to filter out most
flakey thinking and to concentrate on the real issues. If the Luftwaffe
in 1944 was still relying on the whims of 'gifted individuals' (Hitler,
Goering), who would have prided their own (uncriticised) judgement then
a lot of bad ideas would have good through and a lot of good ideas would
have been turned away.


German thinking was predicated on the need to fight a short and sharp
war as a nation sourunded by hostile countries. Avoiding a war of
attrition was essential and avoiding a war on German territory was
also essential.

The surrounding countries were only hostile because of Hitler's
belligerence - he could have been a peaceful leader had he so chosen.
As for laying odds on a short war - having contingency plans in case
your lightning strike does not work is fundamental to military planning.

I don't blame Hitler for it all. Hitler was a symptom of severe
patholgies in Eruopean statecraft, ethics and nationalism. Nor do I
blame the Germans. They were up untill WW1 among the most passive of
nations. Even the Prussian beligerance is a myth when the number of
wars and/or their size is compared to the other Eruopean nations.

France untill recent EU integration has always been beligerant towards
Germany and its states over hundreds of years this goes back before
the Franco-Prussian war and even before Napoleon (when Pussians and
English fouth together). Preventing a unified Germany has always been
a French policy. Poland was rather beligerant towards Germany as well
as often shamefully discriminatory Germans who had come under Polish
rule.

Poland went to war with almost all the neighbours in 1919/20 and had
annexed Wilna from Lithuania, large parts of Germany, the Olsa area
from the CSR (in October 1938!) and large parts of the Ukraine and
Bjelorussia from the USSR. A country with considerable problems with
large ethnic minorities which made up almost 50% of the population.
And a country between Germany and the USSR. And a country armed for
more heavily than germany was in 1935.



The nation was physically to small and to devoid of
materials to handle a war in any other way and not loose thus
substantial offensive capability was emphasised but it was all up
front: resources were not devoted to reinforcements. This was the
thinking even before the Nazis came to power.

Germany had many resources to spare in the early years of the war.
Their industry was still working single shifts until things got really
bad. While Hitler was telling the German people about how well things
were going, Churchill was telling the British that we had to get a
wiggle on or lose - and our industry went to 100 percent from 1940
onwards.

I believe Nazi ideology was grounded into keeping a happy home life
and keeping the Birth rate high and they did not want to take mom away
from her role as mother. It took them a while to turn around their
ideology and their propaganda effort to spread this. In the long term
they were probably right though obviously it was part of their
contribution to their defeat: unless you regard a nation as only an
abstract concept that is equivalent to a state if your population
declines below a crical level your nation is lost and they were
obsessed with this. In 200 years the memories of "White English" and
"White Germans" will surely only footnotes in history books the
decline in Birth rates per 20 year generation is so dramatic.

The Nazis had a "volkish concept of the nation" that focused
obsessively on the survival of its people/race or nacestors not its
institutions.


Much of the German work on Microwaves and Proximity fuses (which
inspired British research)

Um...they told us about their work in these fields?

They did have a Magnetron team, this was disbanded and the engineers
and technicians drafted into the Army. They were hurridly recalled
when the Rotterdam (H2S device) was discovered in a crashed RAF
bomber. Some of the Magnetrons were of apparently good quality. The
Brits Randle and Boot invented the Muliticavity Magnetron not to work
on Radar but as a cheap source of microwaves for their work which was
in direction finding. Single cavity manetrons like the Germans were
using probably would remain stable up to about 30-50 watts output
after which they would refuse to give more power and start becoming
unstable due to thermal effects. This would give an night fighter a
detection range of only 1.5km as apposed to an 8km range in a 16kW
Magnetron. The Germans were ahead in microwave research having
developed microwave radars of 1.3 watt output in 1933 that detected
destroyers up to 1.5km away and could send radio messages 60 km.

http://www.ieee.org/organizations/hi...ts/schwan.html

SCHWAN: Oh, yes. As a matter of fact, when the war started in
1939, the Germans developed the fairly well-known Wurzburg type of
equipment which operated at a wavelength of about one and one-half
meters. They were operating at a rather low frequency by comparison
with the 2400 megahertz which the United States used later in
'forty-three. They never made it to higher frequencies than that. They
operated at lower wavelengths where, of course, resolution is not as
good as it is at the higher frequencies.

They developed some good magnetrons. It's an irony of history that a
few months after the war started in thirty-nine the Nazis closed the
Magnetron Development Laboratory since they thought it unnecessary for
the war. Can you imagine that?
**************************************

The Engineer Nakajima of japan had developed Multicavity resonant
Magnetrons 1 year beofore the British. Ironicaly he worked in Germany
before the war and if the Germany and Japanese had of shared as well
as
the US/UK did things could have turned out different.

http://www.star-games.com/exhibits/j...neseradar.html
Nakajima: In 1953 I traveled around the world without a translator. At
that time I went to London, and at the museum I found exactly the same
thing, which was explained as: "This was invented by some Birmingham
University people in 1940." 1940 means one year later than our
invention.

*******************************
Yes, the Germans were working on radar proximity fuses first and the
British had espionage data of German tests. This induced them to do
start their own effort which yielded good results. I believe a German
engineer disaffected with the Nazis (he had resettled in Norway)
revealed the work to British intelligence. "Oslo Report" was the
name of the intelligence report.

The German work was **** canned as low priority becuase the Germans
researchers could not guarantee that their efforts would come to
deployment within two years.

Presumably it was possible to make fuses that might handle several
hundred G acceleration without to much difficulty but to go beyond
this would presumabluy require speciual efforts in valve technogy
fundementals.

"The initial idea behind radar proximity fuses was suggested by the
Germans.
However, a Hitler dictat caused the device's development within
Germany to a
halt because its development was deemed to be destined to take too
long to
come to fruition; the war would be over by that time.

http://groups.google.com.au/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&threadm=9iv8uk%24dsq%241%40nntp6.u.wash ington.edu&rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26safe%3Doff%26q%3Dflak%2Bpredictor%2Bproximity% 26btnG%3DGoogle%2BSearch

The British received as an invaluable gift a well-made tube, a part
of an
early attempted iteration of such a fuze, which measured electrical
potentials and could serve to trigger a detonator if the potential
detected
were high enough. The gift came as part of what came to be known as
the Oslo
Report, so-named because that was the city in which a German engineer
(IIRC)
disaffected with the Nazi regime, used to transmit this remarkable and
priceless document to the British. In it were described all of the
most
advanced technologies then under consideration by the Hitlerites,
including
the proximity fuse, in great detail.

Great Britain, however, lacked the capacity needed to research and
develop
the device. Along with the resonant cavity magnetron (itself a
development
of original US magnetron research) a diagram of a proposed circuit for
a
proximity fuse was sent as a part of Britain's Tizard mission of
September,
1940 to the US. While the diagram was useful, it proved necessary for
US
firms to pioneer a family of impact-resistant vacuum tubes (strong
enughto
survive being fired at hiigh velocities from a cannon tube) and for a
Canadian firm to pioneer batteries with indeterminate shelf-lives
before a
workable proximity fuze emerged."







was suspended because the anything that
could not be ready in 2 years would be a waste.

Not a waste, a strategic error - no-one to blame but themselves.

Indeed. However were they right? Did the liberated the resources
actualy help them?

Clearly disbanding the magnetron team and the proximity fuse efforts
were mistakes: more so when one cosniders that the magnetron team
ended up in the Army!

Would however the UK have prioritised magnetron work had US resources
not been available?



It seems that at
this point that many of the German might have beens got caned.
Examination of this period is perhaps where it might be said that
Germany's technical loss may be said to lie. It might also just lay in the
fact that Germany lacked the resources to develop them.

Poor prioritization - no-one to blame but themselves. The proximity
fuse was a small printed circuit that any small group of radio men could
have taken forward - there was no great industrial effort needed here.

The ciruit was simple: a doppler shift device. However Hardening the
tubes, inventing the printed circuit board and repeatedly manufaturing
shells, firing them and recovering them would have needed state help.

I expect you get reasonably far just dropping the sheells on their ass
onto corncret (wrecking the tubes and checking what broke) but then
you get battery problems, and the probem of handling 30,000 rpm.

The secret was apparently in placing the tubes in wax and oil to
equalise stress.




The Tiazard
commision handed the proximity fuse and magnetron on a platter for the
USA to develop. The Germans just culled.

Good prioritisation on Tizard's part - hand the designs over to the
people who can mass produce immediately.

Indeed but my point is who do the Germans hand their reserach over to?
The Italians? The Japanese? They did get the French to do some of
their engineering for them and that was their best bet but the Vichy
is hardly the USA.



The excelent Freya and Wurzburg Radars were not integrated into a
defensive system because the bomber naviagation aids were considered
more important.

Integration was a matter laying telephone connections and training a
limited number of staff.

Organisationaly it was more than that. Kammhubber eventualy created
such a system complete with TV to transmit the battle situation but at
the time Navy, Luftwaffe and Army FLAK units all had their fiefdoms
and much politics was involved.

The Freya/Wurburg system required a huge expensive number of radars
because of their limited range and the politicing involved in getting
the system up and running was huge.



If you have started a war, and it has gone
pear-shaped, and your efforts have simply created a hostile world around
you, air defence should then be recognised as a priority. After 1942
the allies were no longer fighting a war dictated by German initiatives
- they were fighting according to their own.

Cheers,

Dave

In article ,
(The Enlightenment) writes:
(Peter Stickney) wrote in message ...
In article ,
Dave Eadsforth writes:

A few points here.

In order to improve altitude performance, you've got to increase the
compression ratio of the induction system, or add an axidizer to the
fuel-air mix to help it burn. This can be done by adding supercharger
stages (Basically one supercharger feeding another, like, say, a
Merlin 60 series engine, or the turbosupercharger/engine driven blower
setups on the P-47 and P-38, or piping something like Nitrous Oxide
into the induction system, as the Germans did.

Nitrous oxide was more a technique the Germans were forced into to
help overcome a German disadvantage in high octane or high test
aviation fuels rather than a paucity in thingking.

No. Nitrous Oxide injection (GM1, in the German nomenclature) as used
by the Germans, did not increase engine power below the critical
altitude of the supercharger. It was used to increase the critical
altitude of the engine, by increasing the partial pressure of oxygen
in the fuel-air mixture.
One of the drivers of the need for this system was the supercharger
layout chosed for their large inline engines, the Daimler-Benz 60x
series, and the Junkers Jumo 211 and 213. Instead of having a
centrifugal blower mounted on the back of the engine, with air fed
from directly behind, thus allowing for easy installation of a second
supercharger stage, and the intercoolers that it requires to keep the
charge temperature down, the Germans went for a transverse
supercharger mounted transversely (cross-wise, if you will, with the
supercharger impeller's axis at right abgles to the engine's
crankshaft) fed from the side. This precluded a second supercharger
stage without a lot of drag-prodicing external ducting. THe Daimlers
also used a hydraylic variable speed coupling to drive the
superchargers on the DB601, DB603, and DB605. This is a very neat
idea. Ideally, it allows the supercharger to only draw off enough
power to produce the desired manifold pressure, so that there is more
power available at the propeller at altitude below the critical
altitude of the engine. There are drawbacks to this - Becasue it had
to operate ofer a wider speed range than gear-driven superchargers,
the efficiency of the DVL superchargers on the Merceded engines was
about 10-15% lower than those on, say, a Merlin or an Allison.
The supercharger drive also isn't as efficient, with losses in the
hydraulic system eating up about 3-4% of teh power needed to drive the
supercharger - It's like the lesser efficiency of a car with an
automatic transmission compared with th esame car with a manual
transmission.

The Germans _did_ use Anti-Detonant Injection (ADI, or MW50 in their
nomenclature) to allow increased manifold pressures (And thus
increased Horsepower) at lower altitudes. This was a 50/50 mix of
Mathanol and Water, injected into the eye of teh supercharger
impeller. It was used in some instances to make up the difference
between the German Low-Octane Avgas (87 Octane), and their High Octane
Avgas (96 Octane, not really high octane) in some engines, or to boost
the power of the high octane-rated engines at low altitudes.


The Germans did have techniques for manufacturing octane and even
higher knock hydrocarbons their technology was however more cumberson
than the US technology and this limited their production rate. Why
this was I don't know. It may have had something to do with the fact
that they had access to only snythetic oils from fischer tropsch and
hydrogenation plants or their own small crude oil industry or
Romania's all of which are regarded as poor quality crudes.
(California crude was rather highly regarded). It may have just been
that they were unaware of the US techniques.

U.S. techniques were fairly widely known. Ethyl Gasoline had been
available since the mid 1930s. Most of the high octane avgas impetus
had come from Jimmy Doolittle at Shell. One would think that when teh
Germans took Rotterdame and Copenhagen that they'd have turned up that
information. Shell is a Dutch company, and their headquarters were in
Rotterdam. (In fact, the Shell Building was used as a Headquarters
building by the Germans.)


--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

In article ,
Dave Eadsforth writes:
Re. the Ar 234A, I believe that this machine made a number of attacks on
the UK, but I do not know when. Do you happen to have any rough dates?

I don't think the Ar 234s made any bombing attacks over the U.K. They
were used against targetsin Belgium and France in late 1944.

Also, do you happen to know if the Ar 234 (of any mark) was ever used as
a recce machine over the UK prior to D-Day?

Not prior to D-Day. The Ar 234s available in June/July 1944 were the
inital models with a skid landing gear, which used a wheeled trolley
for takeoff. Immediately following the Invasion, one or two fo these
prototypes were staged to an airfield in France, where a vcertain
logistical weakness was discovered - It's no use having a Jet Recce
airplane that can stage to a forward airfield in an hour when its
takeoff gear and mechanics have to come by truck, through the Allied
Fighter-Bomber cover. It took until mid-July to get all the pieces
rounded up so that they could fly missions, and by that time, it was a
matter of shutting the barn door after the horse was gone. (It turns
out that they wouldn't have been able to return any useful intel even
if they could have flown sooner. There weren't enough experienced
photointerpreters to sort through the pictures, so the turnaround time
from flights to intel in the hands of the Staff was on the order of a
couple of weeks. Not much use in mobile warfare.

If you get a chance, check out Alfred Price's "The Last Year of the
Luftwaffe." It's an excellent account of what the state of German
Airpower was from just before Normandy until the final collapse.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

In article ,
(Gregory W Shaw) writes:
Others have already hit on what effect higher octane ratings had. Peter
Stickney will probably have one of his great replies coming along soon
too. But here is a quick rundown on what 104/150 octane should provide
for a Merlin 266.

The US had an empirical formula for calculating MAP limits at different
PN. It is a little conservative, but gives a good ballpark figure.

((old MAP -7) * new PN/old PN) +7 = new MAP

So, 66.6 in Hg on 100/130 octane would give:

((66.6 - 7) * 150/130) +7
59.6 * 1.154 + 7 = 75.76 in Hg

The RAF actually used +25 psi, about 80.9 inches.

We know the Merlin 266 was rated at 66.6 in Hg, 1705 hp @ 5750 ft in low
blower. That is enough information to approximate how much power the
engine provides at any altitude.

We also know static pressure at 5750 ft is approx 24.20 in Hg. So,
dividing 66.6 by 24.20 gives us approx 2.75 for the pressure ratio that
the Merlin 266 provides in low blower.

Multiplying static pressure by the pressure ratio gives the manifold
pressure available at any altitude. 80.9 in Hg would be attainable up
to about 500 ft unrammed, and approx 82.4 in Hg at SL.

Since we know it produces 1705 hp @ 66.6 in Hg we can figure how much
it makes at 80.9 in Hg. 1705 * 80/66.6 gives about 2071 hp. Then you
have to take the difference in temp into account. Sqrt of absolute temp
at 5750 ft / absolute temp at 500 ft times 2071 hp.

(sqrt (276.86 / 287.36)) * 2071 = 2032 hp @ 500 ft.

(I'm using the 1976 standard atmosphere for all calculations, older
atmosphere models might provide slightly different figures)

This should be accurate +- about 1%. You can do the same thing for just
about any engine, provided you have an accurate base altitude, power and
MAP rating to start with. I cheated and created an Excel spreadsheet
that does all the work for me.

You need to make sure and use static ratings, a lot of RAF ratings are
with 350 or 400 mph RAM which will screw things up. RAM will cause a
higher rated altitude from the ram pressure, but lower power due to
compression heating.

Great work Greg, and mighty close. (You forgot to factor in the
increased temperature at the lower altitude, which will reduce power
somewhat. It's one of those things where the 90/90 rule comes in -
teh first 90% of the accuracy in the analysis takes up teh first 90%
of the effort, and the last 10% takes up the other 90%!

I've been able to dig up the manufacturer's numbers, as reported in
_Aircraft_Engines_of_the_World_, 1946.

For the Merlin 66, Standard Day, No Ram.
The Combat Ratings in Low Blower we
1705 HP @ 5,750', 3000 RPM/+18 Boost
2000 HP @ SL, 3000 RPM/+25 Boost

These are very close to your numbers, and the effect to the ambient
temperature on the charge air temerature probably make up the
differnce.

Just for the record, here are the numbers in High Blower:
1580 HP @ 16,000', 3000 RPM/+18
1860 HP @ 10,500', 3000 RPM/+25

Other Merlins were also rated for 3000R/+25 on teh 150 PN fuel.
The Merlin 24, with s single-stage, 2-speed blower produced a Combat
Power of:
Low Blower: 1640 HP @ 2,000'; 3000 RPM/+18
1730 HP @ 0'; 3000 RPM/+20.5 (The supercharger
couldn't produce +25# of Boost at Sea Level)
High Blower: 1500 HP @ 9,500'; 3000 RPM/+18
1780 HP @ 4,000'; 3000 RPM/+25

The Merlin 113/114 Series was also re-rated with 150 PN
I'm not sure what their boost limit was on 100/130 fuel, so I'll leave
it out, for now.

Merlin 130 Series engines were also able to use 150 Octane fuel:
Combat Power for a Merlin 130 was:
Low Blower: 1830 HP @ 5,500'; 3000 RPM/+20
2020 HP @ 1,500'; 3000 RPM/+25
High Blower: 1690 HP @ 18,000'; 3000 RPM/+20
1845 HP @ 14,250'; 3000 RPM/+25


Two-Stage supercharged Griffon engines (60 series) were also rated
with 150 PN.
Combat Power for a Griffon 69 was:
Low Blower: 2000 HP @ 6,750'; 2750 RPM/+21.0
2300 HP @ 500'; 2750 RPM/+25
High Blower: 1810 HP @ 21,000'; 2750 RPM/+21.0
2060 HP @ 15,750'; 2750 RPM/+25

TO show you what the effects are of some other approaches, here are
the numbers for an ADI equipped Packard Merlin, the V1650-9 used on
the P-51H:
War Emergency Power:
Low Blower: 1600 HP @ 11,800'; 3000 RPM/67"
1930 HP @ 10,100'; 3000 RPM/80"
High Blower: 1330 HP @ 23,000'; 3000 RPM/67"
1639 HP # 23,500'; 3000 RPM/80" (That's what the
sources say - quite frankly, the altitude number has
to be bogus. It should be around 18,800')

Definitely follow up with a visit to the Fourth Fighter Group Web
page. Mike Williams has done a fantastic job of collecting up data on
this subject and others, and in presenting it to us. Much of the data
is directly from Flight Test Reports of the A&AEE and Central Fighter
Establishment. You can't get any better than that.
It's well worth the time spent there.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

In article , Eunometic
writes
Dave Eadsforth wrote in message news:3J4OP5A0ETHAFw1O
...
In article , The
Enlightenment writes
Dave Eadsforth wrote in message
news:s9BISHBVA3GAFw82
...
In article , WaltBJ
writes
Slightly off track - the Germans did not seem to place the same level
of importance on recce that the Brits and USAF did. Me109s could (some
did) carry a camera in the aft fuselage like the recce P51s (F6?). A
lightened waxed Me109F or G would have a very good chance of
completing a recce pass on an in-and-out basis flown at max speed on a
curving descent or in-and-out at naught feet (prop tips above the wave
tips). It appears to me that the 86R was declared a 'clay pigeon' when
the LW found out Spits and Mosquitoes, appropriately modifed, could
get up that high. Why the LW didn't use 'hot-rodded' photofighters is
beyond me. Maybe they swallowed the 'XX' turned spies' reports as
gospel.
Walt BJ

Yes, the success of agents like 'Garbo' in feeding duff stuff to the
German High Command was remarkable.

Without wanting to go wildly off-topic, there was a programme on UK TV a
few nights ago ('Spitfire Ace') that had some very useful stuff on the
mentality of the RAF versus the that of Luftwaffe in 1940. The RAF
(through the vision and efforts of Dowding) had created a parless air
defence system, while the Luftwaffe had concentrated overmuch on the
lionisation of its individual pilots.

Honestly this sounds like Brits patting themselves on the back while
not looking at the strategic and tactical issues the Germans faced.
(sadly this is a sort of anasthetic as the UK goes down a sewer)

While I agree that we, as a nation, should be organising our lives
better these days, there is no doubt that the British air defence system
of 1940 was unmatched anywhere else in the world, and no-one, not even
the Germans, dare to claim that Goering's boasts of 1940 held water.

The Britsh radar at the time was inferior. It used a laege omni
direction arial at about 10 years waverlenth wid radio direction
finding loops. the German Freya searh radars and Wurzburk radars were
at this time mobile, more accurate. They were too goog in that they
**** caned their micrwave developement on the basis that their radars
were more than good enough.

However as far as a system goes you are right. The Germans lacked IFF
(indentifiucation fried or foe) untill "erstling" came along and they
did not integrate the air defenses. Luftwaffe, Army, Navy and various
regions simply were not integrated properly and respnded with
confusion to a raid.

http://www.fas.org/man/dod-101/ops/docs/97-0609F.pdf:
DEFLATING BRITISH RADAR MYTHS OF WORLD WAR II
A Research Paper
Presented To
The Research Department
Air Command and Staff College
In Partial Fulfillment of the Graduation Requirements of ACSC
by Maj. Gregory C. Clark
March 1997



I think that by 1944 the Allies
had developed a war machine that was thorough enough to filter out most
flakey thinking and to concentrate on the real issues. If the Luftwaffe
in 1944 was still relying on the whims of 'gifted individuals' (Hitler,
Goering), who would have prided their own (uncriticised) judgement then
a lot of bad ideas would have good through and a lot of good ideas would
have been turned away.


German thinking was predicated on the need to fight a short and sharp
war as a nation sourunded by hostile countries. Avoiding a war of
attrition was essential and avoiding a war on German territory was
also essential.

The surrounding countries were only hostile because of Hitler's
belligerence - he could have been a peaceful leader had he so chosen.
As for laying odds on a short war - having contingency plans in case
your lightning strike does not work is fundamental to military planning.

I don't blame Hitler for it all. Hitler was a symptom of severe
patholgies in Eruopean statecraft, ethics and nationalism. Nor do I
blame the Germans. They were up untill WW1 among the most passive of
nations. Even the Prussian beligerance is a myth when the number of
wars and/or their size is compared to the other Eruopean nations.

France untill recent EU integration has always been beligerant towards
Germany and its states over hundreds of years this goes back before
the Franco-Prussian war and even before Napoleon (when Pussians and
English fouth together). Preventing a unified Germany has always been
a French policy. Poland was rather beligerant towards Germany as well
as often shamefully discriminatory Germans who had come under Polish
rule.

Poland went to war with almost all the neighbours in 1919/20 and had
annexed Wilna from Lithuania, large parts of Germany, the Olsa area
from the CSR (in October 1938!) and large parts of the Ukraine and
Bjelorussia from the USSR. A country with considerable problems with
large ethnic minorities which made up almost 50% of the population.
And a country between Germany and the USSR. And a country armed for
more heavily than germany was in 1935.



The nation was physically to small and to devoid of
materials to handle a war in any other way and not loose thus
substantial offensive capability was emphasised but it was all up
front: resources were not devoted to reinforcements. This was the
thinking even before the Nazis came to power.

Germany had many resources to spare in the early years of the war.
Their industry was still working single shifts until things got really
bad. While Hitler was telling the German people about how well things
were going, Churchill was telling the British that we had to get a
wiggle on or lose - and our industry went to 100 percent from 1940
onwards.

I believe Nazi ideology was grounded into keeping a happy home life
and keeping the Birth rate high and they did not want to take mom away
from her role as mother. It took them a while to turn around their
ideology and their propaganda effort to spread this. In the long term
they were probably right though obviously it was part of their
contribution to their defeat: unless you regard a nation as only an
abstract concept that is equivalent to a state if your population
declines below a crical level your nation is lost and they were
obsessed with this. In 200 years the memories of "White English" and
"White Germans" will surely only footnotes in history books the
decline in Birth rates per 20 year generation is so dramatic.

The Nazis had a "volkish concept of the nation" that focused
obsessively on the survival of its people/race or nacestors not its
institutions.


Much of the German work on Microwaves and Proximity fuses (which
inspired British research)

Um...they told us about their work in these fields?

They did have a Magnetron team, this was disbanded and the engineers
and technicians drafted into the Army. They were hurridly recalled
when the Rotterdam (H2S device) was discovered in a crashed RAF
bomber. Some of the Magnetrons were of apparently good quality. The
Brits Randle and Boot invented the Muliticavity Magnetron not to work
on Radar but as a cheap source of microwaves for their work which was
in direction finding. Single cavity manetrons like the Germans were
using probably would remain stable up to about 30-50 watts output
after which they would refuse to give more power and start becoming
unstable due to thermal effects. This would give an night fighter a
detection range of only 1.5km as apposed to an 8km range in a 16kW
Magnetron. The Germans were ahead in microwave research having
developed microwave radars of 1.3 watt output in 1933 that detected
destroyers up to 1.5km away and could send radio messages 60 km.

http://www.ieee.org/organizations/hi...anscripts/schw
an.html

SCHWAN: Oh, yes. As a matter of fact, when the war started in
1939, the Germans developed the fairly well-known Wurzburg type of
equipment which operated at a wavelength of about one and one-half
meters. They were operating at a rather low frequency by comparison
with the 2400 megahertz which the United States used later in
'forty-three. They never made it to higher frequencies than that. They
operated at lower wavelengths where, of course, resolution is not as
good as it is at the higher frequencies.

They developed some good magnetrons. It's an irony of history that a
few months after the war started in thirty-nine the Nazis closed the
Magnetron Development Laboratory since they thought it unnecessary for
the war. Can you imagine that?
**************************************

The Engineer Nakajima of japan had developed Multicavity resonant
Magnetrons 1 year beofore the British. Ironicaly he worked in Germany
before the war and if the Germany and Japanese had of shared as well
as
the US/UK did things could have turned out different.

http://www.star-games.com/exhibits/j...neseradar.html
Nakajima: In 1953 I traveled around the world without a translator. At
that time I went to London, and at the museum I found exactly the same
thing, which was explained as: "This was invented by some Birmingham
University people in 1940." 1940 means one year later than our
invention.

*******************************
Yes, the Germans were working on radar proximity fuses first and the
British had espionage data of German tests. This induced them to do
start their own effort which yielded good results. I believe a German
engineer disaffected with the Nazis (he had resettled in Norway)
revealed the work to British intelligence. "Oslo Report" was the
name of the intelligence report.

The German work was **** canned as low priority becuase the Germans
researchers could not guarantee that their efforts would come to
deployment within two years.

Presumably it was possible to make fuses that might handle several
hundred G acceleration without to much difficulty but to go beyond
this would presumabluy require speciual efforts in valve technogy
fundementals.

"The initial idea behind radar proximity fuses was suggested by the
Germans.
However, a Hitler dictat caused the device's development within
Germany to a
halt because its development was deemed to be destined to take too
long to
come to fruition; the war would be over by that time.

http://groups.google.com.au/groups?h...fe=off&threadm
=9iv8uk%24dsq%241%40nntp6.u.washington.edu&rnum=1 &prev=/groups%3Fhl%3Den%26lr%3D
%26ie%3DUTF-8%26oe%3DUTF-8%26safe%3Doff%26q%3Dflak%2Bpredictor%2Bproximity% 26btn
G%3DGoogle%2BSearch

The British received as an invaluable gift a well-made tube, a part
of an
early attempted iteration of such a fuze, which measured electrical
potentials and could serve to trigger a detonator if the potential
detected
were high enough. The gift came as part of what came to be known as
the Oslo
Report, so-named because that was the city in which a German engineer
(IIRC)
disaffected with the Nazi regime, used to transmit this remarkable and
priceless document to the British. In it were described all of the
most
advanced technologies then under consideration by the Hitlerites,
including
the proximity fuse, in great detail.

Great Britain, however, lacked the capacity needed to research and
develop
the device. Along with the resonant cavity magnetron (itself a
development
of original US magnetron research) a diagram of a proposed circuit for
a
proximity fuse was sent as a part of Britain's Tizard mission of
September,
1940 to the US. While the diagram was useful, it proved necessary for
US
firms to pioneer a family of impact-resistant vacuum tubes (strong
enughto
survive being fired at hiigh velocities from a cannon tube) and for a
Canadian firm to pioneer batteries with indeterminate shelf-lives
before a
workable proximity fuze emerged."







was suspended because the anything that
could not be ready in 2 years would be a waste.

Not a waste, a strategic error - no-one to blame but themselves.

Indeed. However were they right? Did the liberated the resources
actualy help them?

Clearly disbanding the magnetron team and the proximity fuse efforts
were mistakes: more so when one cosniders that the magnetron team
ended up in the Army!

Would however the UK have prioritised magnetron work had US resources
not been available?



It seems that at
this point that many of the German might have beens got caned.
Examination of this period is perhaps where it might be said that
Germany's technical loss may be said to lie. It might also just lay in the
fact that Germany lacked the resources to develop them.

Poor prioritization - no-one to blame but themselves. The proximity
fuse was a small printed circuit that any small group of radio men could
have taken forward - there was no great industrial effort needed here.

The ciruit was simple: a doppler shift device. However Hardening the
tubes, inventing the printed circuit board and repeatedly manufaturing
shells, firing them and recovering them would have needed state help.

I expect you get reasonably far just dropping the sheells on their ass
onto corncret (wrecking the tubes and checking what broke) but then
you get battery problems, and the probem of handling 30,000 rpm.

The secret was apparently in placing the tubes in wax and oil to
equalise stress.




The Tiazard
commision handed the proximity fuse and magnetron on a platter for the
USA to develop. The Germans just culled.

Good prioritisation on Tizard's part - hand the designs over to the
people who can mass produce immediately.

Indeed but my point is who do the Germans hand their reserach over to?
The Italians? The Japanese? They did get the French to do some of
their engineering for them and that was their best bet but the Vichy
is hardly the USA.



The excelent Freya and Wurzburg Radars were not integrated into a
defensive system because the bomber naviagation aids were considered
more important.

Integration was a matter laying telephone connections and training a
limited number of staff.

Organisationaly it was more than that. Kammhubber eventualy created
such a system complete with TV to transmit the battle situation but at
the time Navy, Luftwaffe and Army FLAK units all had their fiefdoms
and much politics was involved.

The Freya/Wurburg system required a huge expensive number of radars
because of their limited range and the politicing involved in getting
the system up and running was huge.



If you have started a war, and it has gone
pear-shaped, and your efforts have simply created a hostile world around
you, air defence should then be recognised as a priority. After 1942
the allies were no longer fighting a war dictated by German initiatives
- they were fighting according to their own.

Cheers,

Dave

Thanks very much for your points - there are a number of things in your
summary that I did not know until now.

On the political side, I did know that there were some big stresses in
Europe in the 1930s, and any German leader would have to have exercised
sound judgement to keep things on an even keel. German rearmament alone
could have made the rest of Europe cautious in their dealings and
stability could have been maintained for decades. Where it all went
wrong was when Hitler started on his trail of conquest.

But having done so, he would have done better to adopt the 'ego free'
process of planning and execution of military operation. On the allied
side, good ideas stood a chance - on the German side it seems to have
been 'trust in the Fuhrer' and pull your neck in.

But once the genie was out of the bottle so many things were done in a
crazy manner; the treatment of the people in conquered territories by
the SS for one - the people of Russia would have turned against Stalin
in the early days; but not after the SS atrocities. Real vision, and
appreciation of consequences of action, seems to have been lacking in
Hitler's planning processes.

Cheers,

Dave

--
Dave Eadsforth

In article , Peter Stickney
writes
In article ,
Dave Eadsforth writes:
Re. the Ar 234A, I believe that this machine made a number of attacks on
the UK, but I do not know when. Do you happen to have any rough dates?

I don't think the Ar 234s made any bombing attacks over the U.K. They
were used against targetsin Belgium and France in late 1944.

Also, do you happen to know if the Ar 234 (of any mark) was ever used as
a recce machine over the UK prior to D-Day?

Not prior to D-Day. The Ar 234s available in June/July 1944 were the
inital models with a skid landing gear, which used a wheeled trolley
for takeoff.

I've seen a photo - quite a sight.

Immediately following the Invasion, one or two fo these
prototypes were staged to an airfield in France, where a vcertain
logistical weakness was discovered - It's no use having a Jet Recce
airplane that can stage to a forward airfield in an hour when its
takeoff gear and mechanics have to come by truck, through the Allied
Fighter-Bomber cover.

Would it be too awful to suggest that the whole programme was on the
skids?

It took until mid-July to get all the pieces
rounded up so that they could fly missions, and by that time, it was a
matter of shutting the barn door after the horse was gone. (It turns
out that they wouldn't have been able to return any useful intel even
if they could have flown sooner. There weren't enough experienced
photointerpreters to sort through the pictures, so the turnaround time
from flights to intel in the hands of the Staff was on the order of a
couple of weeks. Not much use in mobile warfare.

Hmm, no German equivalent of Constance Babington-Smith then?

If you get a chance, check out Alfred Price's "The Last Year of the
Luftwaffe." It's an excellent account of what the state of German
Airpower was from just before Normandy until the final collapse.

Would you believe I bought a copy last week? I haven't had time to read
it yet - but it's nice to know I have made a good choice!

Thanks,

Dave

--
Dave Eadsforth

"Dave Eadsforth" wrote in message
...
In article ,
Emmanuel.Gustin
writes
Dave Eadsforth wrote:

: Yes, the success of agents like 'Garbo' in feeding duff stuff to
the
: German High Command was remarkable.

The familiar problem, as far as I know:
Too many different intelligence services, every
one a part of the personal empire of a different
Nazi leader, and unwilling or unable to cooperate.
And of course the 'Abwehr' leaked like a sieve.

The Germans did produce recce versions of fighters,
usually with fewer guns and more fuel; in addition
to cameras of course. But I suspect the Bf 109 was
just less adaptable to the task than the Spitfire.
It was even smaller.

The Spitfire had inherited a D-shaped leading edge
structure from its direct ancestor, the Supermarine
227, which used this as a condensor for its
steam-cooled Goshawk engine. This made a great fuel
tank for the long-range reconnaissance versions.
With better fuel and more powerful engines, these
models could also operate at higher weights and
reach higher altitudes than Bf 109s.

On the other hand Ju 88s were less suitable for
reconnaissance than Mosquitoes, because they were
bigger and slower. Still, the Germans did develop
a high-performance recce aircraft in the Ar 234A.

Emmanuel Gustin

Thanks for that!

Re. the Ar 234A, I believe that this machine made a number of
attacks on
the UK, but I do not know when. Do you happen to have any rough
dates?

Also, do you happen to know if the Ar 234 (of any mark) was ever
used as
a recce machine over the UK prior to D-Day?

Leutnant Erich Somner made the world fist jet reconaisance flight on
August 2 1944. in the Arado 234 V7. The V7 indicating that it was
the 7th prootype. (V stands for Versuchs or esperimental) which was
hurridly adapted to obtain the photorecon of the situation at the
Cherbourg Penisuala. He had accomplished more in this mission than
the entire luftwaffe did in 2 months. It took 12 photographic
interpreters 2 days to produce an intitial report. This revealed that
the Allies had landed 1.5 million men.

Somner was a test pilot and responsible for having the Lofte 7
bombsight linked into the PDS autopilot.

On September 9th Somner conducted a reconaisance mission over London
and the Thames estury. On the outward bound leg he came upon a
reconaisance Mosquito intent on the same type of mission. As both
pilots aircraft were unarmed the pilots simply waved at each other.

Somner despite being given orders to fly the reconaisance flight was
almost court martialed as unbeknownst to him flying a jet over Britain
was strictly forbiden Somners friend the Horst Gotz flew his Fiesler
Storch to see Goebells and this may have save hime from the court
martial. "Exellent Propaganda" was the comment of Goebells's
assisatant.


Early Arado 234A used a trolley to take of and skid to land. The
Ardo 234B bomber an undercariage and had a fueselage 1 inch wider to
accomodate the recessed bomb bay and compensate for fuel loss. The
recon Arado was swiched over to an normal undercarriage as the 10
minutes needed to retrieve the aircraft left it too vulnerable to
straffing.

Bombing raids on the UK would have been possible with a light bomb
load and heavier loads with the more developed versions.

The Arado had an accurate computing Bomb sight the Lotfe 7 (this was
regarded as more accurate than allied sights and it was once
recomended that it be copied for the RAF) it also apparently had the
EGON blind bombing system (similar to OBOE apparently) and a computing
dive bombing sight.

The few aircarft to enter service (about 70) were to busy with recon
tasks and attacking supply lines to overfly the UK I assume.
Nevertheless EGON was probably as accurate as oboe though it is hard
to imagine that even a Lotfe 7 would be accurate at the 10,000 meters
that would be used over the British isles.

Dive bombing had to be done with care as the aircraft lacked dive
breaks and in conditions of tension produced by AAA the pilot could
easily get in trouble with Mach. The Arado 234 was a pretty aircraft
because of its amazing smoothness.

It's designer Rudiger Kosin lofted the wing on a computer and rather
than rivet the wing on points of equal chord it was riveted at points
of equal curvature to produce a wrinkel free su Kosin also invented
the crescent wing (as in handley page victor) to overcome the Arado
234s mach limitation. He also invented the Krueger flap. (Krueger
was the wind tunnel technican who did the tests)






Cheers,

Dave

--
Dave Eadsforth

On Sun, 1 Feb 2004 23:53:51 -0500, (Peter Stickney)
wrote:

U.S. techniques were fairly widely known. Ethyl Gasoline had been
available since the mid 1930s. Most of the high octane avgas impetus
had come from Jimmy Doolittle at Shell.

In terms of raising the PIN above 87 octane with 100 octane,
absolutely. It took pressure from Doolittle to generate a USAAC
requirement for testing in 1935, and the results of that testing were
instrumental in justifying a British Air Ministry orders in 1936-7.

150 octane ratings appeared to me, from my reading of the supply
sources in the PRO and secondary sources in the oil company's
histories, to have evolved from investigation of rich-mixture response
of 100-octane supplies in the early forties. Xylidine, mentioned at
the beginning of the thread, was a Shell-derived substitute for cumene
to increase the PIN, but it was orginally used to reduce the quantity
of other iso-octanes required to blend with TEL-added feedstock to
produce 100 octane, and so stemmed from measures taken to increase
production of 100-octane supplies in 1942-43 rather than from a desire
to increase the octane rating to start with. Or at least that's how I
read it.

One would think that when teh
Germans took Rotterdame and Copenhagen that they'd have turned up that
information. Shell is a Dutch company, and their headquarters were in
Rotterdam.

Shell in the US were operationally administered seperately.

(In fact, the Shell Building was used as a Headquarters
building by the Germans.)

There was even a small hydrogenation plant in Rotterdam used for
producing iso-octanes for experimental testing, which surely could
have been used even if in small quantities.

Gavin Bailey