In article >,
Dave Eadsforth > writes:
>
>
> Good day, good people,
>
> I wondered if anyone out there (in all probability, Peter!) could help
> me understand more fully the process by which the Merlin engine was
> enabled to use 150 octane fuel; one feature of which was the addition of
> the Xylidine anti-knock compound. (This was touched on in a thread
> last year, I recall.)

If you can wait, I've got to dig out some files & make sure of some
references, but I'll have a comprehensive answer in about a day's
time. In the meantime, I'll chuck out a tidbit or two.


> I understand that 150 octane fuel became available during 1944 - I don't
> know when (a date would be welcome), but it was available in time to
> boost the performance of those Spitfires that were assigned to knocking
> down the V1s. What I would like to find out is what might have been
> done to the Merlin to allow it to run on the stuff?

As far as engine modifications go, Not a lot, really, other than
changing the settings in the Manifold Pressure Regulators and possibly
tweaking the jets in the carburetors.

The higher engine output comes from the increased Manifold Pressure.
High Octane fuels tend to have a somewhat lower energy content than
those with lower Octane (or Performance) Ratings. (Technically, if
it's over 100 Octane, it's a Performance Number.) The energy
content's really not much of a difference, though, so we can skip it
for now. One of the consequences of increasing the Manifold Pressure
is a higher Charge Temperature (The temperature of the compressed air
in the Intake Manifold). If that temperature gets high enough, the
fuel-air mixture will self-ignite - Detonation - "Knock" is too kind a
word for what happens at +25 Boost when uncontrolled burning, and its
attendant shockwaves get going in a Recip's cylinder. The higher the
Performance Number, the more resistance to detonation, and you can use
the extra power that the higher manifold pressure gives you without
having to walk home.
Note that there are other alternatives as well, such as Anti Detonant
Injection, or Water Injection, where an aerosol of water, or a
water/alcohol mix, is sprayed into the air as it's benig compressed to
absorb some of the heat, and lower the Charge Temperature.

>
> Was the use of 150 octane restricted to particular marks of engine?

As far as I know, it was mostly used on Spit Mk IXs with Merlin 66
engines. There were also some experiments with 150 PN fuel in Rolls
Griffons, and Packard Merlins, as well.

> I read somewhere that it was supposed to provide an effective increase
> in power of about 15 percent - by allowing a higher manifold pressure.
> Is that figure of 15 percent correct?

I'll have real numbers for you in a day or so, but that sounds about
right. Of course, the increase in power comes with a decrease in
Critical Altitude - The supercharger can only compress things so much,
after all, so to get a higher Manifold Pressure, you've got to start
with thicker air.

> Was the conversion to 150 octane done by merely adjusting the existing
> arrangements for the supply of fuel, or was there a need for new fuel
> supply components (carbs etc.)? And would the permitting of the
> additional boost have mandated the exchange of some internal engine
> parts (bearings, crankshafts, etc.)?

The bearings/cranks/conrods/pistons, etc, were stock components.
Teh carbs were teh same - but I don't know if they got tweaked. The
automatic Boost Pressure Regulators would, of course, need to be
reset. It was the sort of job that could be done at the Squadron,
rather than Depot, level. You didn't have to go in & rebuild
anything. I'd prefer to start with an almost new engine, however. An
engine with a little running time has worked out all its initial
stress relief.

> Would the use of 150 octane have automatically permitted a higher
> ceiling for the machines that used it? Or don't things work quite that
> simply! (I understand that specially prepared Spitfires had been able
> to fly to at least 44,000 feet by 1943. Would I be right or wrong to
> simply assume that 150 octane would have enabled them to go higher?)

No, As with anythig else in Aviation (Or any other Engineering), it's
a balancing act. You can only get so much of a compression ratio out
of a Supercharger, for any given drive speed. In order to get more
boost, you've got to start with thicker air, so the Critical Altitude
actually decreases. When you're chasing V-1s, though, or fighting
against Me 109s, or Fw 190s, that's not a bad thing. The Daimler Benz
engines in the 109, by virtue of their variable-speed blowers, which
didn't require as much power to run at low altitudes, gave a big
advantage down low. The BMW 801 on an Fw 190 had a geared blower, but
the critical altitude for the low gear was very low, down near Sea
Level.
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. The drawback is that
it takes more of hte engine's power, in the gear-driven examples, to
compress the air that much more. That means that at lower altitudes,
you're at a disadvantage. Or, you've got got to haul around a bunch
of tanks, regulators, pipes, valves, & all that for teh Nitrous
system. You've only got a limited quatity of Nitrous aboard, and you
can pretty much guarantee that it'll run out right when you need it.
Or, worse yet, the storage bottles could get damaged. Leaking
Oxidizers is a Bad Thing, especially when somebody's shooting at you.

More later, with real numbers attached.

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

>British based Spitfire IX squadrons had converted to 150 octane
>(actually 100/150 octane, for lean/rich rating) by, or during, May 44.

Is this the same as 100 octane, then? As used for example in the
Curtiss P-40?

all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

In article
thlink.net>, Orval Fairbairn >
writes
>In article >,
> Dave Eadsforth > wrote:
>
>> Good day, good people,
>>
>> I wondered if anyone out there (in all probability, Peter!) could help
>> me understand more fully the process by which the Merlin engine was
>> enabled to use 150 octane fuel; one feature of which was the addition of
>> the Xylidine anti-knock compound. (This was touched on in a thread
>> last year, I recall.)
>>
>> I understand that 150 octane fuel became available during 1944 - I don't
>> know when (a date would be welcome), but it was available in time to
>> boost the performance of those Spitfires that were assigned to knocking
>> down the V1s. What I would like to find out is what might have been
>> done to the Merlin to allow it to run on the stuff?
>>
>> Was the use of 150 octane restricted to particular marks of engine?
>>
>> I read somewhere that it was supposed to provide an effective increase
>> in power of about 15 percent - by allowing a higher manifold pressure.
>> Is that figure of 15 percent correct?
>>
>> Was the conversion to 150 octane done by merely adjusting the existing
>> arrangements for the supply of fuel, or was there a need for new fuel
>> supply components (carbs etc.)? And would the permitting of the
>> additional boost have mandated the exchange of some internal engine
>> parts (bearings, crankshafts, etc.)?
>>
>> Would the use of 150 octane have automatically permitted a higher
>> ceiling for the machines that used it? Or don't things work quite that
>> simply! (I understand that specially prepared Spitfires had been able
>> to fly to at least 44,000 feet by 1943. Would I be right or wrong to
>> simply assume that 150 octane would have enabled them to go higher?)
>>
>> Thanks in anticipation.
>>
>> Cheers,
>>
>> Dave
>
>150 octane means that you can add more boost to the superchargers
>without damage to engine components. There MAY ahve been materials
>compatability issues with the octane boosters, however.
>
>You can run "rubber" components (seals, hoses, etc.) on petroleum-based
>fuels and have no problems; you can run the same components on
>naptha-based fuels and have no problems. It is when you switch from one
>to the other (either way, BTW) that hoses crack and seals leak.

Thanks for that point.

(It rings a bell - I read that when the US first entered the war,
Britain supplied the Pacific-based USAAF with some aviation fuel that
had originated from a SE Asian oilfield, and it was so differently
formulated that it actually did corrode the seals and hoses.)

Cheers,

Dave

--
Dave Eadsforth

In article >, Hildegrin
> writes
>Dave Eadsforth > wrote in message
>news:<o+F5SWAHQUGAFwMy
>...
>> Good day, good people,
>>
>> I wondered if anyone out there (in all probability, Peter!) could help
>> me understand more fully the process by which the Merlin engine was
>> enabled to use 150 octane fuel; one feature of which was the addition of
>> the Xylidine anti-knock compound. (This was touched on in a thread
>> last year, I recall.)
>>
SNIP of incredibly useful amount of historical data.

Thanks very much for taking the time to type in all that information -
very much appreciated.

Re. your pondering about whether the Griffon engine was boosted over 25
in. Years ago, I was invited to take a look inside a Shackleton, and
while in the cockpit I noted that the boost gauges went up to something
phenomenal - I cannot now remember what the numbers were, but they were
definitely well in excess of 25. I did take a photo of the interior and
I will now try to look it out and see if the numbers are readable.

Someone out there who knows more about Shacks might be able to give an
accurate figure.

Thanks again,

Dave

--
Dave Eadsforth

In article >, Peter Stickney
> writes
>In article >,
> Dave Eadsforth > writes:
>>
>>
>> Good day, good people,
>>
>> I wondered if anyone out there (in all probability, Peter!) could help
>> me understand more fully the process by which the Merlin engine was
>> enabled to use 150 octane fuel; one feature of which was the addition of
>> the Xylidine anti-knock compound. (This was touched on in a thread
>> last year, I recall.)
>
>If you can wait, I've got to dig out some files & make sure of some
>references, but I'll have a comprehensive answer in about a day's
>time. In the meantime, I'll chuck out a tidbit or two.
>
SNIP of much appreciated theoretical and practical stuff
>

Thanks, Peter; that summary has given me a pretty firm grasp of the
essentials for boosting engines. If you do have any additional material
that would be great.

I have recently seen some stuff on the lengths that the Germans went to
to get the Ju86 to fly at high altitude. I had not realised previously
that nitrous oxide could be used with a diesel engine - but the Ju86P
did for its (1,000 HP) Jumo 207B-3s.

Re. diesel engines and the energy it takes to supercharge; that would
explain the planned construction of the Ju86R-3, not just with more
powerful engines (1500 HP Jumo 208s) but also installing the two stage
blower for these within the Ju86 fuselage and driving it with a separate
engine - a supercharged DB 605.

I have pondered why it was that the Luftwaffe did not try to boost the
Ju86R-1s and 2s a bit more in early 1944, when they needed to see what
the allies were doing on the south coast of England, and hence could
have used a recce plane that had a good chance of getting home with the
goods. Perhaps the Jumo 207s had already been boosted to the limit...

Cheers,

Dave

--
Dave Eadsforth

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

"WaltBJ" > wrote in message
om...
> 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).


The Me-109G-8 recce variant had a camera in the aft fuselage and did
conduct some photo recon missions over the channel area in 1944.

Keith

(Hildegrin) wrote:

>Higher octane allows you to use higher boost pressures. It doesn't
>create more boost, it just allows you to "overboost" the engine at
>lower alts. Thus at rated alt and above, increased octane had no real
>effect (it may have reduced power by a tiny amount, because the fuel
>has a lower calorifc value, I think).
>

Yes, this is exactly right...some think that the higher the
Octane Rating the more "powerful" the fuel when actually high
Octane fuel is less 'powerful' that low Octane fuel. You get the
extra power because you can increase the Manifold Air Pressure
(boost) without causing DETONATION. This is the whole reason
behind high octane useage. Heavy detonation will trash an engine
in short order so you must prevent it.

Water injection also results in higher engine power in a slightly
different manner. Without water the fuel controls supply more
fuel than the engine needs, this very rich mixture cools the
charge in the cylinders lowering the pressure and so prevents
detonation. With water, the fuel mixture is automatically leaned
considerably by the 'de-richment valve' therefore producing more
power.
--

-Gord.

Dave Eadsforth > wrote in message >...
>
> Thanks very much for taking the time to type in all that information -
> very much appreciated.
>
That's OK. I didn't do anything towards researching the information.
The thanks really belong to the chap who spent a long time trawling
through the PRO for the info in the first place.

> Re. your pondering about whether the Griffon engine was boosted over 25
> in. Years ago, I was invited to take a look inside a Shackleton, and
> while in the cockpit I noted that the boost gauges went up to something
> phenomenal - I cannot now remember what the numbers were, but they were
> definitely well in excess of 25. I did take a photo of the interior and
> I will now try to look it out and see if the numbers are readable.
>
I'm mainly interested in the Griffon 65, and wether any other models
of Griffon were fitted to the Spitfire XIV during the war, but any
info on Griffons with 150 octane fuel is very helpful.

Cub Driver > wrote in message >...
> >British based Spitfire IX squadrons had converted to 150 octane
> >(actually 100/150 octane, for lean/rich rating) by, or during, May 44.
>
> Is this the same as 100 octane, then? As used for example in the
> Curtiss P-40?
>
> all the best -- Dan Ford
> email:
>

The common 100 octane fuel had an octane rating of 100/130, which
means 100 in lean mixture, 130 in rich mixture. 150 octane was
actually 100/150. I suppose that means no difference in lean mixture,
but in rich it had a tremendous effect. The Merlin went from 67" to
82", for example (although the USAAF rated them more conservatively,
at 72" iirc)

100/150 wasn't in use until the spring of 1944, although it was being
tested in 1943.

In article >,
(Hildegrin) writes:
> Cub Driver > wrote in message >...
>> >British based Spitfire IX squadrons had converted to 150 octane
>> >(actually 100/150 octane, for lean/rich rating) by, or during, May 44.
>>
>> Is this the same as 100 octane, then? As used for example in the
>> Curtiss P-40?


> The common 100 octane fuel had an octane rating of 100/130, which
> means 100 in lean mixture, 130 in rich mixture. 150 octane was
> actually 100/150. I suppose that means no difference in lean mixture,
> but in rich it had a tremendous effect. The Merlin went from 67" to
> 82", for example (although the USAAF rated them more conservatively,
> at 72" iirc)
>
> 100/150 wasn't in use until the spring of 1944, although it was being
> tested in 1943.

The Lean Mixture/Rich Mixture rating system didn't get adopted until
late 1942 or early 1943. (For those who don't know, the first number
is the Lean Mixture rating, the second is the Rich Mixture.
Before then, ratings were rather arbitrary, and true antiknock
performance depended on various characteristics of the individual
blend. Since Gasoline isn't a specific chemical, but a blend of
various hydrocarbons, performacne at one particular test point didn't
necessarily mean the same performance across the full range of
conditions. The Lean/Rich rating system, standardized testing using
calibrated sensors to detect knock, and the definition of
characteristics that were seen to be important (Antiknock, Vapor
Pressure, viscosity, Specific Gravity, & a whole slew of other stuff)
was an important bit of standardization by the U.S. and U.K.

Hildegren, have you checked out the N.A.C.A. Technical Reports Server?
(It's also mirrored at Cranwell) Among the thousands of reports is a
whole series on Aviation Fuel development, and the development of
testing methods.

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

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. 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.

Cheers,

Dave

--
Dave Eadsforth

In article >, Keith Willshaw
> writes
>
>"WaltBJ" > wrote in message
om...
>> 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).
>
>
>The Me-109G-8 recce variant had a camera in the aft fuselage and did
>conduct some photo recon missions over the channel area in 1944.
>
>Keith
>
>

Hi Keith,

Do you happen to know whether these were conducted at high level, low
level, or the max speed altitude for the 109G-8?

Cheers,

Dave

--
Dave Eadsforth

On 30 Jan 2004 14:50:00 -0800,
(Hildegrin) wrote:

>The common 100 octane fuel had an octane rating of 100/130,

Okay, thanks.

I reckon that piling 100/150 on top of 100/130 is what led to the
regular use of the two octanes in naming the fueld.

In 1942 in Southeast Asia, 100 (presumably 100/130) was called just
that, or "high octane" to distinguish it from the 80 octane used by
the RAF.


all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

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

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.

Greg Shaw

(Peter Stickney) wrote in message >...
> In article >,
> Dave Eadsforth > writes:
> >
> >
> No, As with anythig else in Aviation (Or any other Engineering), it's
> a balancing act. You can only get so much of a compression ratio out
> of a Supercharger, for any given drive speed. In order to get more
> boost, you've got to start with thicker air, so the Critical Altitude
> actually decreases. When you're chasing V-1s, though, or fighting
> against Me 109s, or Fw 190s, that's not a bad thing. The Daimler Benz
> engines in the 109, by virtue of their variable-speed blowers, which
> didn't require as much power to run at low altitudes, gave a big
> advantage down low. The BMW 801 on an Fw 190 had a geared blower, but
> the critical altitude for the low gear was very low, down near Sea
> Level.
> 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.

> The drawback is that
> it takes more of hte engine's power, in the gear-driven examples, to
> compress the air that much more. That means that at lower altitudes,
> you're at a disadvantage. Or, you've got got to haul around a bunch
> of tanks, regulators, pipes, valves, & all that for teh Nitrous
> system. You've only got a limited quatity of Nitrous aboard, and you
> can pretty much guarantee that it'll run out right when you need it.
> Or, worse yet, the storage bottles could get damaged. Leaking
> Oxidizers is a Bad Thing, especially when somebody's shooting at you.
>
> More later, with real numbers attached.


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.

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.

Nitprous oxide also was used only at higher altitudes: water methanol
injection was used at low altitude.

The Ta 152H has a watern methanol and nitorous oxide system. The
clipped wing Ta 152C has only water methanol for its BB603LA

The Jumo 213E had a two stage 3 speed supercharger WITH an induction
cooler. It still had water methanol and nitorus oxide (nickamed HA HA
system because Nitorus oxide was laughting gas)

Ta 152H Engine: Junkers Jumo 213E-1 twelve-cylinder liquid-cooled
engine rated at 1750 hp for takeoff (2050 hp with MW 50 boost) and
1320 hp at 32,800 feet (1740 feet with GM 1 boost). Maximum speed: 332
mph at sea level (350 mph with MW 50 boost), 465 mph at 29,530 feet
with MW 50 boost, 472 mph at 41,010 feet with GM 1 boost. Service
ceiling was 48,550 feet with GM 1 boost. Initial climb rate was 3445
feet/minute with MW 50 boost. Weights were 8642 pounds empty, 10,472
pounds normal loaded, 11,502 pounds maximum. Wingspan 47 feet 41/2
inches, length 35 feet 1 2/3 inches, height 11 feet 0 1/4 inches, wing
area 250.8 square feet.

The Ta 152C-1 was powered by a Daimler-Benz DB 603LA twelve-cylinder
liquid cooled engine rated at 2100 hp (2300 hp with MW 50) for takeoff
and 1750 hp at 29,530 feet (1900 hp at 27,560 feet with MW 50). Armed
with one engine-mounted 30-mm MK 108 cannon with 90 rounds, two
fuselage-mounted 20-mm MG 151 cannon with 250 rpg, and two
wing-mounted 20-mm MG252 cannon with 175 rpg. Maximum speed was 227
mph at sea level (356 mph with MW 50), 436 mph at 37,730 feet (460 mph
at 32,810 feet with MW 50). Initial climb rate was 3050 feet per
minute and service ceiling was 40,350 feet. Weights were 8849 lbs
empty, 10,658 lbs normal loaded, and 11,733 pounds maximum. Wingspan
was 36 feet 1 inch, length was 35 feet 6 1/2 inches, height was 11
feet 1 inch, and wing area was 290.89 square feet.

Dave Eadsforth > wrote in message >...
> 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)


> 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 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.

Much of the German work on Microwaves and Proximity fuses (which
inspired British research) was suspended because the anything that
could not be ready in 2 years would be a waste. 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 may be said to lie. It migh also just lay in the
fact that Germany lacked the resources to develop them. The Tiazard
commision handed the proximity fuse and magnetron on a platter for the
USA to develop. The Germans just culled.

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





> Cheers,
>
> Dave

In article >, The
Enlightenment > writes
(Peter Stickney) wrote in message news:<dbocvb-
>...
>> In article >,
>> Dave Eadsforth > writes:

SNIP of repeated material
>
>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.
>
>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.
>
>Nitprous oxide also was used only at higher altitudes: water methanol
>injection was used at low altitude.
>
>The Ta 152H has a watern methanol and nitorous oxide system. The
>clipped wing Ta 152C has only water methanol for its BB603LA
>
>The Jumo 213E had a two stage 3 speed supercharger WITH an induction
>cooler. It still had water methanol and nitorus oxide (nickamed HA HA
>system because Nitorus oxide was laughting gas)
>
>Ta 152H Engine: Junkers Jumo 213E-1 twelve-cylinder liquid-cooled
>engine rated at 1750 hp for takeoff (2050 hp with MW 50 boost) and
>1320 hp at 32,800 feet (1740 feet with GM 1 boost). Maximum speed: 332
>mph at sea level (350 mph with MW 50 boost), 465 mph at 29,530 feet
>with MW 50 boost, 472 mph at 41,010 feet with GM 1 boost. Service
>ceiling was 48,550 feet with GM 1 boost. Initial climb rate was 3445
>feet/minute with MW 50 boost. Weights were 8642 pounds empty, 10,472
>pounds normal loaded, 11,502 pounds maximum. Wingspan 47 feet 41/2
>inches, length 35 feet 1 2/3 inches, height 11 feet 0 1/4 inches, wing
>area 250.8 square feet.
>
>The Ta 152C-1 was powered by a Daimler-Benz DB 603LA twelve-cylinder
>liquid cooled engine rated at 2100 hp (2300 hp with MW 50) for takeoff
>and 1750 hp at 29,530 feet (1900 hp at 27,560 feet with MW 50). Armed
>with one engine-mounted 30-mm MK 108 cannon with 90 rounds, two
>fuselage-mounted 20-mm MG 151 cannon with 250 rpg, and two
>wing-mounted 20-mm MG252 cannon with 175 rpg. Maximum speed was 227
>mph at sea level (356 mph with MW 50), 436 mph at 37,730 feet (460 mph
>at 32,810 feet with MW 50). Initial climb rate was 3050 feet per
>minute and service ceiling was 40,350 feet. Weights were 8849 lbs
>empty, 10,658 lbs normal loaded, and 11,733 pounds maximum. Wingspan
>was 36 feet 1 inch, length was 35 feet 6 1/2 inches, height was 11
>feet 1 inch, and wing area was 290.89 square feet.

Thanks for this very useful summary - very much appreciated.

Cheers,

Dave

--
Dave Eadsforth

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.
>
>> 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.

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

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

> 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.

> 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 may be said to lie. It migh 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 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.
>
>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. 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

--
Dave Eadsforth

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/history_center/oral_histories/transcripts/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/japaneseradar/japaneseradar.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.washington.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 were:
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/history_center/oral_histories/transcripts/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/japaneseradar/japaneseradar.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.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

Dave Eadsforth > wrote in message >...
> In article >, The
> Enlightenment > writes
> (Peter Stickney) wrote in message news:<dbocvb-
> >...
> >> In article >,
> >> Dave Eadsforth > writes:
>
> SNIP of repeated material
> >
> >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 thinking.
> >
> >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.
> >
> >Nitprous oxide also was used only at higher altitudes: water methanol
> >injection was used at low altitude.
> >
> >The Ta 152H has a watern methanol and nitorous oxide system. The
> >clipped wing Ta 152C has only water methanol for its BB603LA
> >
> >The Jumo 213E had a two stage 3 speed supercharger WITH an induction
> >cooler. It still had water methanol and nitorus oxide (nickamed HA HA
> >system because Nitorus oxide was laughting gas)
> >
> >Ta 152H Engine: Junkers Jumo 213E-1 twelve-cylinder liquid-cooled
> >engine rated at 1750 hp for takeoff (2050 hp with MW 50 boost) and
> >1320 hp at 32,800 feet (1740 feet with GM 1 boost). Maximum speed: 332
> >mph at sea level (350 mph with MW 50 boost), 465 mph at 29,530 feet
> >with MW 50 boost, 472 mph at 41,010 feet with GM 1 boost. Service
> >ceiling was 48,550 feet with GM 1 boost. Initial climb rate was 3445
> >feet/minute with MW 50 boost. Weights were 8642 pounds empty, 10,472
> >pounds normal loaded, 11,502 pounds maximum. Wingspan 47 feet 41/2
> >inches, length 35 feet 1 2/3 inches, height 11 feet 0 1/4 inches, wing
> >area 250.8 square feet.
> >
> >The Ta 152C-1 was powered by a Daimler-Benz DB 603LA twelve-cylinder
> >liquid cooled engine rated at 2100 hp (2300 hp with MW 50) for takeoff
> >and 1750 hp at 29,530 feet (1900 hp at 27,560 feet with MW 50). Armed
> >with one engine-mounted 30-mm MK 108 cannon with 90 rounds, two
> >fuselage-mounted 20-mm MG 151 cannon with 250 rpg, and two
> >wing-mounted 20-mm MG252 cannon with 175 rpg. Maximum speed was 227
> >mph at sea level (356 mph with MW 50), 436 mph at 37,730 feet (460 mph
> >at 32,810 feet with MW 50). Initial climb rate was 3050 feet per
> >minute and service ceiling was 40,350 feet. Weights were 8849 lbs
> >empty, 10,658 lbs normal loaded, and 11,733 pounds maximum. Wingspan
> >was 36 feet 1 inch, length was 35 feet 6 1/2 inches, height was 11
> >feet 1 inch, and wing area was 290.89 square feet.
>
> Thanks for this very useful summary - very much appreciated.
>
> Cheers,
>
> Dave


You might find it interesting to know that the xylidine amine used to
produce the 150 octane fuel was also used by the Germans in their
"Tonka" series of hypergolic storable fuels (the oxidiser was nitric
acid generally). These fuels were intended for the X4 air to air
missile, the Wasserfall SAM and the BMW003R rocket/jet combo. The
Russians used Tonka more or less unchanged for their missiles post
WW2.

Therefor it can be concluded that the Germans were confident of of
being able to produce xylidine in quantity. The compound does however
have many isomers.

Nitric acid sound nasty but but it can't explode, evaporate or
spontaneously decompose when it gets too hot or too cold.

A great deal of info on German WW2 syn fuels can be found at
http://wwww/fischer-tropsch.org

"Peter Stickney" > wrote in message
...
> 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.

I though one reason the Germans didn't have two stage superchargers
was because the lower levels of boost possible with their lower octane
fuels and larger swept volumes simply made duel stage superchargers
unnecessry or pointless. I also note that the Jumo 213E of the Ta
152H did have a two stage supercharger and an induction cooler so it
must have been possible, possibly with coaxial shafts? The Jumo 213E
also had an induction cooler which is presumably a cooling stage
before the induction manifold unlike the two stage merlin which had
the cooler between stages. I suspect that the intercooler of the
merlin is more efficient while the induction cooler method produces a
cooler charge.




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.

I think that some specialist Me 109G, those with the DB605AS engine,
were high altitude specialists. This was the superchager of the DB603
grafted onto to 603.

> 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.

This Mercedes system was apparently developed from an mercedes
automatic transmision system for cars.


>
> 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.)

The Germans had good chemistry and good chemists. The biggest
industry in the world even today. As early as 1939-40 Goering was
calling for the production of large quanties of high test avialtion
fuels what came of this demand I don't know.

I suspect that the effort of producing octane was such that they
simply did not build their force around it. Synthetic fuel already
cost 4 times the same as mineral oils.



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

"Peter Stickney" > wrote in message
...

<snip>
> The higher engine output comes from the increased Manifold Pressure.
> High Octane fuels tend to have a somewhat lower energy content than
> those with lower Octane (or Performance) Ratings. (Technically, if
> it's over 100 Octane, it's a Performance Number.)

No, higher octane fuel burns slower; but it contains more usable energy.

"Gord Beaman" > wrote in message
...
> (Hildegrin) wrote:
>
> >Higher octane allows you to use higher boost pressures. It doesn't
> >create more boost, it just allows you to "overboost" the engine at
> >lower alts. Thus at rated alt and above, increased octane had no real
> >effect (it may have reduced power by a tiny amount, because the fuel
> >has a lower calorifc value, I think).
> >
>
> Yes, this is exactly right...some think that the higher the
> Octane Rating the more "powerful" the fuel when actually high
> Octane fuel is less 'powerful' that low Octane fuel. You get the
> extra power because you can increase the Manifold Air Pressure
> (boost) without causing DETONATION. This is the whole reason
> behind high octane useage. Heavy detonation will trash an engine
> in short order so you must prevent it.

Lead tetra ethyl is not short of energy, Gord.

> Water injection also results in higher engine power in a slightly
> different manner.

No. Water injection only prevents the connecting rod bearings from being
destroyed by detonation. Much the same as an EGR valve on automobile
engines injecting exast gas into the manifold.

Dave Eadsforth wrote:
> 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!

I also think it's a great book.

John

Peter Stickney > wrote:
>
> 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%!
>

Thanks Peter,

I did take temp into account, that dropped power from 2070 to 2030 hp @
500 ft. Although I did fubar it a little, I used 5800 ft for the base
temp rather than 5750 ft, that would change power to 2033 hp instead of
2032 hp.

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

The change from 500 ft to SL drops power down to about 2026 hp. It looks
like I'm about 1% over published figures. Given the amount of slop
involved all around I'll take that. Particularly for something I can do
with a standard atmosphere chart and a $2.00 calculator in about 1
minute.

I have seen two different methods of calculating temp affects. I am
using (sqrt (old abs temp/ new abs temp)) * hp

I have also seen simpler version of old abs temp / new abs temp * hp

Using that method I come up with 1996 hp @ 500 ft and 1989 hp @ SL. It
could be that simple, a difference in calculation methods.

My spreadsheet is a bit more complicated, it takes blower power into
account as well. And being able to see hp/MAP at multiple altitudes
simultaneously allows me to do some curve fitting that makes for a bit
better accuracy.

I have used it for a number of engines successfully. Given two data
points, generally military power and WEP, I can typically get it to
match within .5 in Hg and 1-2 hp at all altitudes I have published data
for. Given the accuracy of the starting data and all the other slop that
is probably about as accurate as possible.

>
> 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.

I haven't visited there in about 6 months or so. I need to go back and
see what new stuff he has. Great resource.

Thanks for the additional Merlin & Griffon data, I'll add it to my
stash.

Greg Shaw

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

SNIP of previous detail

>>
>> 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.
>
Shades of WWI...

>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)
>
A lot of innovation for the period...most impressive.
>
Thanks very much for that rundown - it seems it was quite a machine.

Cheers,

Dave

--
Dave Eadsforth

In article >, The
Enlightenment > writes
>Dave Eadsforth > wrote in message news:<xZSPrjAdETHAFw1$
>...
>> In article >, The
>> Enlightenment > writes
>> (Peter Stickney) wrote in message news:<dbocvb-
>> >...
>> >> In article >,
>> >> Dave Eadsforth > writes:
>>
>> SNIP of repeated material
>> >
>> >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 thinking.
>> >
>> >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.
>> >
>> >Nitprous oxide also was used only at higher altitudes: water methanol
>> >injection was used at low altitude.
>> >
>> >The Ta 152H has a watern methanol and nitorous oxide system. The
>> >clipped wing Ta 152C has only water methanol for its BB603LA
>> >
>> >The Jumo 213E had a two stage 3 speed supercharger WITH an induction
>> >cooler. It still had water methanol and nitorus oxide (nickamed HA HA
>> >system because Nitorus oxide was laughting gas)
>> >
>> >Ta 152H Engine: Junkers Jumo 213E-1 twelve-cylinder liquid-cooled
>> >engine rated at 1750 hp for takeoff (2050 hp with MW 50 boost) and
>> >1320 hp at 32,800 feet (1740 feet with GM 1 boost). Maximum speed: 332
>> >mph at sea level (350 mph with MW 50 boost), 465 mph at 29,530 feet
>> >with MW 50 boost, 472 mph at 41,010 feet with GM 1 boost. Service
>> >ceiling was 48,550 feet with GM 1 boost. Initial climb rate was 3445
>> >feet/minute with MW 50 boost. Weights were 8642 pounds empty, 10,472
>> >pounds normal loaded, 11,502 pounds maximum. Wingspan 47 feet 41/2
>> >inches, length 35 feet 1 2/3 inches, height 11 feet 0 1/4 inches, wing
>> >area 250.8 square feet.
>> >
>> >The Ta 152C-1 was powered by a Daimler-Benz DB 603LA twelve-cylinder
>> >liquid cooled engine rated at 2100 hp (2300 hp with MW 50) for takeoff
>> >and 1750 hp at 29,530 feet (1900 hp at 27,560 feet with MW 50). Armed
>> >with one engine-mounted 30-mm MK 108 cannon with 90 rounds, two
>> >fuselage-mounted 20-mm MG 151 cannon with 250 rpg, and two
>> >wing-mounted 20-mm MG252 cannon with 175 rpg. Maximum speed was 227
>> >mph at sea level (356 mph with MW 50), 436 mph at 37,730 feet (460 mph
>> >at 32,810 feet with MW 50). Initial climb rate was 3050 feet per
>> >minute and service ceiling was 40,350 feet. Weights were 8849 lbs
>> >empty, 10,658 lbs normal loaded, and 11,733 pounds maximum. Wingspan
>> >was 36 feet 1 inch, length was 35 feet 6 1/2 inches, height was 11
>> >feet 1 inch, and wing area was 290.89 square feet.
>>
>> Thanks for this very useful summary - very much appreciated.
>>
>> Cheers,
>>
>> Dave
>
>
>You might find it interesting to know that the xylidine amine used to
>produce the 150 octane fuel was also used by the Germans in their
>"Tonka" series of hypergolic storable fuels (the oxidiser was nitric
>acid generally). These fuels were intended for the X4 air to air
>missile, the Wasserfall SAM and the BMW003R rocket/jet combo. The
>Russians used Tonka more or less unchanged for their missiles post
>WW2.
>
>Therefor it can be concluded that the Germans were confident of of
>being able to produce xylidine in quantity. The compound does however
>have many isomers.
>
>Nitric acid sound nasty but but it can't explode, evaporate or
>spontaneously decompose when it gets too hot or too cold.
>
>A great deal of info on German WW2 syn fuels can be found at
>http://wwww/fischer-tropsch.org

Thanks for the link - I'll check it out.

Cheers,

Dave

--
Dave Eadsforth

In article >, Emmanuel Gustin
> writes
>"Dave Eadsforth" > wrote in message
...
>
>> 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 believe the Ar 234 only made reconnaissance flights, not
>bombing attacks, on Britain. Most flights were over the
>Normandy beaches, and later in support of the Ardennes
>offensive, and also over Northern Italy. Apparently the
>last Luftwaffe reconnaissance flight over England was made
>by a Ar 234 based in Stavanger, Norway, on 10 August 1945.
>No doubt there were earlier ones as well, but I have no data.
>
>> 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?
>
>No, the first operational missions were in August 1944, when
>the V-5 and V-7 prototypes were sent to Juvincourt near
>Reims; pilots Sommer and Goetz made 14 flights over the
>beaches of Normandy. This, incidentally, was said to have
>gathered more data than the whole reconnaissance effort of
>the Luftwaffe in the previous two months.
>

Thanks for those refs - look what they achieved once they got going!

Cheers,

Dave

--
Dave Eadsforth

"Tarver Engineering" > wrote in message >...
> "Peter Stickney" > wrote in message
> ...
>
> <snip>
> > The higher engine output comes from the increased Manifold Pressure.
> > High Octane fuels tend to have a somewhat lower energy content than
> > those with lower Octane (or Performance) Ratings. (Technically, if
> > it's over 100 Octane, it's a Performance Number.)
>
> No, higher octane fuel burns slower; but it contains more usable energy.


The octane rating or RON (Research Octane Number) of a fuel has
nothing to do with its energy content. All hydrocarbons have an
energy content of about 11.5kW.Hr per kg. (about 41Mega.Joules per kg)
Ethyle and Methyl alcohole for instance have a RON of about 130
(which is why it is used in indianapolis car racing) yet have around
half the energy content of gasoline.

The fuels physical density does vary with gasoline being about 0.73kg
per litre while diesel is about 0.78kg per liter. Military aviation
fuels for piston engines, gas trubines and rockets are generally
designed to be physically as dense as possible.

While, as you say, an increased RON means that more of the fuels
energy can be used in a piston engine because it can be given a higher
compression ratio and therefore expansion ratio without preignition or
knocking. If the same gasoline is burned in a multifuel diesel, gas
turbine or wankel the best or worst RON makes no difference at all.

Higher RON number do two things: First they eliminate pre-ignition due
to hot surfaces or the high temperatures caused by compression.
Second they prevent explosive combustion. Combustion should be a
controlled burn at subsonic velocities along a wavefront explosive
combustion (not the technical term) means that the combustion becomes
supersonic and is propagated by infra red radiation simultaneously in
the mixture.

The higher RON of Allied engines seems to have been used not to
increase compression ratio to obtain more power but to allow higher
emergency boost pressures and this practice would not increase fuel
efficiency just maximum power. Both the Merlin and the German Daimler
Benz and Junkers Jumo engines seem to have had a compression ration of
around 6.5. (varying between 6.2 to 6.9 and also varying as to which
bank of cylinders due to the con rods/king rod differences). I
recollect the distinct impression that the Merlin even had LOWER
compression ratios than the German engines.

Diesel engines are given a cetane rating. high cetane numbers are
generally desirable as this means the fuel is easy to ignite but slow
to burn. A centane number of 45 is considered good and 30 is low.

The German synthetic fuel fischer tropsch plants produced
extraordinarily high centane ratings of around 85 (catalysts produce
long linear chains). This was so high it meant that exhaust
temperatures went up by 25% and efficienciues down by 5% as the fuel
barely finished its combustion by the end of the power stroke.
Generally German diesel was a mixture of high cetane Fischer Tropsch
diesel blended with low cetane diesel from the hydrogenation plants.
This then gave an ideal blend.

Oddly despite the ease of producing diesel they often had to make
substitute diesel (maximum power suffered) by blending 95 gasoline
with 5% motor oil as gasoline production was emphasised. It was the
Russians that used the safer diesel in their tanks.

"Tarver Engineering" > wrote in message >...
> "Gord Beaman" > wrote in message
> ...
> > (Hildegrin) wrote:
> >
> > >Higher octane allows you to use higher boost pressures. It doesn't
> > >create more boost, it just allows you to "overboost" the engine at
> > >lower alts. Thus at rated alt and above, increased octane had no real
> > >effect (it may have reduced power by a tiny amount, because the fuel
> > >has a lower calorifc value, I think).
> > >
> >
> > Yes, this is exactly right...some think that the higher the
> > Octane Rating the more "powerful" the fuel when actually high
> > Octane fuel is less 'powerful' that low Octane fuel. You get the
> > extra power because you can increase the Manifold Air Pressure
> > (boost) without causing DETONATION. This is the whole reason
> > behind high octane useage. Heavy detonation will trash an engine
> > in short order so you must prevent it.
>
> Lead tetra ethyl is not short of energy, Gord.

The amount of TEL added makes little difference to the energy content
of a fuel becuase it is so small an amount. I don't even know how
much energy it releases upon combustion if it does so at all.

Ricardo, the great British engineer, developed the idea of using Tetra
Ehyle Lead (TEL) because he reasoned that the milky color of gasoline
was causing it to ignite due to to the transmision and absorbtion of
infra red radiation rather than burn smoothly. TEL acted as a
clarifying agent and this is how it increase the RON in a variable
displacement test engine. That was the theory at least.

Higher RON number do two things: First they eliminate pre-ignition due
to hot surfaces or the high temperatures caused by compression.
Second they prevent explosive combustion. Combustion should be a
controlled burn at subsonic velocities along a wavefront caused by
thermal conduction explosive combustion (not the technical term) means
that the combustion becomes supersonic and is propagated by infra red
radiation simultaneously in the mixture rather than smoothly along a
wavefront.


>
> > Water injection also results in higher engine power in a slightly
> > different manner.
>
> No. Water injection only prevents the connecting rod bearings from being
> destroyed by detonation. Much the same as an EGR valve on automobile
> engines injecting exast gas into the manifold.

Water injection does two things:

1 It lowers the temperature of the charge thus preventing preignition.
2 It increase the density of the air and thus allows more air into the
combustion chambers and allows the supercharger to compress the same
amount of air for less work.

When engines are run rich the oversupply of fuel also cools the air in
the same way. Side effect is loss of efficiency and flames and smoke
from exhaust which your enemy can use to guage your intentions.

In article >,
(Gregory W Shaw) writes:
> Peter Stickney > wrote:
>>
>> 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%!
>>
>
> Thanks Peter,
>
> I did take temp into account, that dropped power from 2070 to 2030 hp @
> 500 ft. Although I did fubar it a little, I used 5800 ft for the base
> temp rather than 5750 ft, that would change power to 2033 hp instead of
> 2032 hp.
>
> (sqrt (276.86 / 287.36)) * 2071 = 2032 hp @ 500 ft.
>
> The change from 500 ft to SL drops power down to about 2026 hp. It looks
> like I'm about 1% over published figures. Given the amount of slop
> involved all around I'll take that. Particularly for something I can do
> with a standard atmosphere chart and a $2.00 calculator in about 1
> minute.

It's certainly within the difference that you're going to find
between individual engines. ANd therefore, more than accurate enough.

The temperature factor that I was considering, though, was within the
supercharger, and, to split it a bit more, the temperature addition
contributed by the individual stages, with teh intercooling between
the Aux and Mainstage factored in. (Then there's the difference in
impeller efficiency that occurs as the conditions change - If you're
not careful, it can drive you sane! It's that old 90-90 rule again. )
It wasn't the HP value that I was getting different, but the altitude.
Even that was well within tolerance, so I'd say our models agree.

Not Criticism at all, but Congratulation.

> I have seen two different methods of calculating temp affects. I am
> using (sqrt (old abs temp/ new abs temp)) * hp

Which is the closest one, although there are aberrations. The
published data for teh V1650-7 (The engine used on later P-51Bs and
the P-51D, don't match up. Even the Specific Engine Characteristics
table in the Pilot's Operating Handbook doesn't seem quite right.

> I have also seen simpler version of old abs temp / new abs temp * hp
>
> Using that method I come up with 1996 hp @ 500 ft and 1989 hp @ SL. It
> could be that simple, a difference in calculation methods.

The Standard Atmosphere of that time was a bit different, as well,
which could also account for it. THe thing with trying to nail down
these numbers is that they aren't that exact in reality. Every
engine's different, every engine wears differently, and every day is
different. They're never that close.

> My spreadsheet is a bit more complicated, it takes blower power into
> account as well. And being able to see hp/MAP at multiple altitudes
> simultaneously allows me to do some curve fitting that makes for a bit
> better accuracy.

Good show. I've some similar tools, myself. (Of course). It's turned
out to be a necessity in sorting out the Variable Speed blowers that
the Germans, and later, Pratt & Whitney used. The normal way to
presenting the performance numbers for tham is just too abstract, and
so it requires a lot of backfitting to sort them out.
>
> I have used it for a number of engines successfully. Given two data
> points, generally military power and WEP, I can typically get it to
> match within .5 in Hg and 1-2 hp at all altitudes I have published data
> for. Given the accuracy of the starting data and all the other slop that
> is probably about as accurate as possible.
>
That's excellent. We'll have to compare notes sometime.

> Thanks for the additional Merlin & Griffon data, I'll add it to my
> stash.

Plenty more if you need it, Greg, just send me a list, and I'll se
what I can do.

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

On Mon, 2 Feb 2004 23:39:25 +0100, "Emmanuel Gustin"
> wrote:

>"Dave Eadsforth" > wrote in message

>by a Ar 234 based in Stavanger, Norway, on 10 August 1945.
>

What was a luftwaffe unit doing in Stavanger on the 10 Aug 45 ?



greg
--
You do a lot less thundering in the pulpit against the Harlot
after she marches right down the aisle and kicks you in the nuts.

"Emmanuel Gustin" > wrote in message
...
> "Greg Hennessy" > wrote in message
> ...
>
> > What was a luftwaffe unit doing in Stavanger on the 10 Aug 45 ?
>
> Sounds absurd, but considerable German forces were still
> holding far-out regions in late 1945, when the Reich was
> crumbling...
>
> As for the presence of aircraft in Stavanger, this was a good
> location for recconnaissance (if you did not want to fly through
> Allied-controlled airspace on the Western front). The Luftwaffe
> still provided some support for the remaining U-boats, and there
> was even a plan to attack Scapa Flow with 'Mistel' composites...
>

However the explanation is probably rather more prosaic

In the book "Wings of the Luftwaffe", written by Eric 'Winkle' Brown
he notes that several Arado aircraft were ferried from Stavanger
to the RAE in the UK. As there was a shortage of qualified
allied pilots a number of these ferry flights were made by
German pilots.The last of these flights was made in October 1945.

Keith

On Tue, 3 Feb 2004 13:32:54 +0100, "Emmanuel Gustin"
> wrote:

>"Greg Hennessy" > wrote in message
...
>
>> What was a luftwaffe unit doing in Stavanger on the 10 Aug 45 ?
>
>Sounds absurd, but considerable German forces were still
>holding far-out regions in late 1945, when the Reich was
>crumbling...
>

I had heard of weather units holding out, However I am suprised that the
norwegians hadnt ejected them considering it was 4 months after the end of
hostilities.

>As for the presence of aircraft in Stavanger, this was a good
>location for recconnaissance (if you did not want to fly through
>Allied-controlled airspace on the Western front).

That I can understand.


greg

--
You do a lot less thundering in the pulpit against the Harlot
after she marches right down the aisle and kicks you in the nuts.

"Eunometic" > wrote in message
om...
> "Tarver Engineering" > wrote in message
>...
> > "Gord Beaman" > wrote in message
> > ...
> > > (Hildegrin) wrote:
> > >
> > > >Higher octane allows you to use higher boost pressures. It doesn't
> > > >create more boost, it just allows you to "overboost" the engine at
> > > >lower alts. Thus at rated alt and above, increased octane had no real
> > > >effect (it may have reduced power by a tiny amount, because the fuel
> > > >has a lower calorifc value, I think).
> > > >
> > >
> > > Yes, this is exactly right...some think that the higher the
> > > Octane Rating the more "powerful" the fuel when actually high
> > > Octane fuel is less 'powerful' that low Octane fuel. You get the
> > > extra power because you can increase the Manifold Air Pressure
> > > (boost) without causing DETONATION. This is the whole reason
> > > behind high octane useage. Heavy detonation will trash an engine
> > > in short order so you must prevent it.
> >
> > Lead tetra ethyl is not short of energy, Gord.
>
> The amount of TEL added makes little difference to the energy content
> of a fuel becuase it is so small an amount. I don't even know how
> much energy it releases upon combustion if it does so at all.

Thus cancelling your other post, Eunometic.

> Ricardo, the great British engineer, developed the idea of using Tetra
> Ehyle Lead (TEL) because he reasoned that the milky color of gasoline
> was causing it to ignite due to to the transmision and absorbtion of
> infra red radiation rather than burn smoothly. TEL acted as a
> clarifying agent and this is how it increase the RON in a variable
> displacement test engine. That was the theory at least.

In reality, TEL slows the burn rate of gasoline, thus allowing for more
spark advance and the elimiation of detonation.

<snip of further cut and paste>