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

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.