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

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

In article , Keith Willshaw
writes

"WaltBJ" wrote in message
. com...
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

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

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

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

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 , 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