Merlin Engines
Robert.Muir
Allison? Also what was the difference between the Merlin and
other RR engines like the Grifon, etc.?
Bob
Charles K. Scott
mu...@churchill.ColumbiaSC.NCR.COM (Robert.Muir) writes:
I can only tell you what I know about the Merlin and what little I know
about the Allison.
It has already been stated that the Merlin was about 60 cu in. less
displacement than the Allison but developed more horsepower. The
Merlin was a double overhead cam type valve arrangement with four
valves per cylinder. Ironically this is being touted now by many auto
manufacturers as absolutely cutting edge. The Merlin also drove the
prop through a spur type reduction gear and the engine normally was
turning in the vicinity of 3,000 rpm or better when at full speed.
The biggest difference I can think of is in the area of supercharging.
The Merlin had (has) a geared supercharger that in the later engines
was a two stage affair. It operated in the first stage up to 12,000
feet wherin the second stage would cut in. This happened with dramatic
results and greatly increased power at that point. Pierre Clostermann
spoke of an anxious moment as he was circling up and away from several
pursuing Focke Wulf's, things were getting pretty dicey and he was
sweating the altimeter when he finally reached 12,000 and the second
blower kicked in with a thump and he immediately began pulling away
from the Germans.
The Allison had a different blower set up or at least less ultimate
pressure and it just wasn't as effective. The P-38 employed a gigantic
exaust driven turbo supercharger to pressurize it's Allisons and it was
VERY problematic. It apparently overpressurized the engines to the
point where even using 130 octane gas, they were detonating fiercely
and loosing engines in a spectacular fashion was pretty common for the
P-38's. The intercooler was also a problem in that it was piped all up
and down the leading edge of the wing which made it very vulnerable to
damage from combat. The Greenland P-38, by the way, was one of this
type of P-38's.
If combat occurred only below 12,000 feet, the Allison engined fighters
would have made a good name for themselves. But it didn't. Most of
the European combats occurred well above that in the rarified air of
30,000 feet and only Messershmitts, Mustangs and the occasional good
running P-38 could fight up there. I don't mention the Focke Wulf's
because their performance fell off steeply after 20,000 feet and the
Spitfires were struggling along with a nose high attitude at 30,000ft
(source JG 26).
Corky Scott
Misty Dauwalder
escort.
Scott Olson
: What was it about the RR Merlin that was so much better than the
: Allison? Also what was the difference between the Merlin and
: other RR engines like the Grifon, etc.?
Most versions of the Merlin (except for special low-altitude
rated engines) had superchargers, the Allisons generally didn't
(false economy). This meant that the Allisons had poor medium
and high altitude performance compared to the Merlins. The
Griffon was a more powerful engine than the Merlin, it turned
the prop the other way (in general), and came into production
later than the Merlin. The Griffon often drove a 5-bladed prop,
where the Merlin generally drove a 2-4 blade unit.
Scott
Anders Pettersson
> mu...@churchill.ColumbiaSC.NCR.COM (Robert.Muir) writes:
>
> > What was it about the RR Merlin that was so much better than the
> > Allison? Also what was the difference between the Merlin and
> > other RR engines like the Grifon, etc.?
The big difference between Merlin and Griffon is the displacement, from the top off
my head the Griffon is roughly 10 litres bigger (circa 35 litres compared to 26 (?)
for the Merlin). I have a book home written by Bill Gunston called "Rolls Royce
aeroengines", I could really recommend that one, quite good.
/Anders Petterson
email: eua...@eua.ericsson.se
Analytical Methods {NWNet}
supercharger. They all did - the superchargers were single stage,
single speed and were lousy - that was the problem. The one exception
was the Allisons for P-38s, which were turbocharged. I suppose the the
engine for P-63s was also an exception, as it had a second supercharger
stage, remotely located and driven with an extension shaft.
-Dave Lednicer
da...@amiwest.com
Dan Ford
All of which helps answer an earlier question: how come the Flying
Tigers in "mediocre" P-40s fared relatively well against the Japanese.
- Dan <dan....@unh.edu>
On 1 Feb 1995, Charles K. Scott wrote:
> It has already been stated that the Merlin was about 60 cu in. less
> displacement than the Allison but developed more horsepower. The
> Merlin was a double overhead cam type valve arrangement with four
> valves per cylinder. Ironically this is being touted now by many auto
> manufacturers as absolutely cutting edge. The Merlin also drove the
> prop through a spur type reduction gear and the engine normally was
> turning in the vicinity of 3,000 rpm or better when at full speed.
^^^^^^^^^
The Tomathawk IIB (P-40C equivalent) flown by the AVG Tigers would throw
a piston at much slower rpms, I think 2,000 being the ideal.
> If combat occurred only below 12,000 feet, the Allison engined fighters
> would have made a good name for themselves. But it didn't. Most of
> the European combats occurred well above that in the rarified air of
> 30,000 feet and only Messershmitts, Mustangs and the occasional good
Japanese bombers over Rangoon typically flew at 14,000 feet. Japanese
army fighters functioned very well I think at 20,000 feet, but I doubt
they ever got as high as 30,000 in the early years, and their
improvisization of a slant-mounted 37 mm cannon in their interceptors to
attack B-29s from below suggests they still found altitude a problem in
1945. (To be sure, time-to-climb was also a factor. They had an hour's
warning, and they required an hour to climb to attack altitude.)
Ken Jernstedt and Parker Dupouy of the AVG once took up their Tomahawks
to see how high they would fly. At around 22,000 feet (I am working on a
5-year-old memory) the P-40 would wobble as if were on a bed of marbles,
fall off, and it was all they could do to get back up to altitude again.
Emmanuel.Gustin
: What was it about the RR Merlin that was so much better than the
: Allison? Also what was the difference between the Merlin and
: other RR engines like the Grifon, etc.?
The Merlin had a mechanical supercharger, single-stage in early models,
two-stage in marks later than 61. The Allison V-1710 was only equipped
with a supercharger after the end of the war. So WWII aircraft equipped
with the V-1710 suffered from poor performance at higher altitudes,
unless they had turbochargers, like the P-38 had.
The Griffon was also a V-12, but it had a larger displacement than the
Merlin (Bore 152.4mm and stroke 167.64mm for the Griffon, bore 137.16mm
and stroke 152.4mm for the Griffon.) Rolls-Royce designed the Griffon so
that the engines itself was clean of accesories, but had a gearbox at its
aft end to drive external accessories. As a result, the Griffon could be
placed in the same airframes as the Merlin with a minimal change.
Emmanuel Gustin
Scott Swartzell
about aviation, but it IS a question about the
Merlin, as built by Packard.....
I saw a picture today of an American PT boat,
and it showed one of the three 'Packard Marine
Engines,' which put out 1350hp, and ran on
aviation fuel. The picture shows a huge V-type
engine, and it looks to be a DOHC engine. Is
this a Packard Merlin? I had never heard of
that the Merlin was used in PT's, but it sure
looks like one.
Scott
C050...@ubvm.cc.buffalo.edu
an aero engine, but it's not a Merlin. According to Frank D. Johnson's
"United States PT Boats of World War II":
"The work done between the wars by the Packard engine company in con-
junction with the racing efforts & financial support of Gar Wood...
made possible the availability of an excellent source of power for all
the operation PT boats produced during WW2. The 12 cylinder Packard
Marine engine 4M-2500 - an outgrowth of the famous 750 hp Liberty
aircraft engine introduced in 1925 by Packard's Col. J.G. Vincent -
was a highly dependable lightweight unit producing 1200 hp in its
early production version. Later in the war the engine's output was
increased to 1350 hp and then finally to 1500 hp...Typically, the
1350 hp version with its gear-driven centrifugal supercharger,
produced its maximum rated power output at 2400 rpm and 41.2" of
mercury manifold pressure. Three engines running at this speed in
an 80' Elco (PT) boat would consume almost 500 gal of 100 octane
avgas in one hour. At a cruising speed of 35 kts with the max.
sustained rpm rating for the engines of 2000 rpm, the same boat
would consume about 300 gal of gasoline giving the boat a range of
about 520 mi. with a typical full fuel load of 3000 gal. (Hey! That's
the second PT boat question I've answered tonite. Does that make me an
expert?)
Bob Cianciosa
The Moral of the Work
"In War: Resolution
In Defeat: Defiance
In Victory: Magnanimity
In Peace: Goodwill"
W.S. Churchill - "The Second World War"
Andrew Madison
Okay, I think I get it, but there's lots of little tidbits going around on
this issue, that depending upon interpretation could mean entirely
different things.
Here's what I get out of the discussion so far:
Emmanuel says that during WWII, the big differentiator between a
P-51 RR Merlin and a similar but Allison equiped A-36 is that the
RR Merlin had a mechanical supercharger. I've long known that the Allison
versus Merlin "Mustangs" were differentiated by high altitude "performance."
Whatever that means. "Wings" uses this phrase ad naseum but without any
detailed substantiation. I also interpret the ABOVE to mean that the
difference between the two types of aircraft was a simple matter of normal
aspiration versus super-charging.
Other posters have implied that its more complex. Two stage supers's
versus single stage super's. Or even throwing in turbo's which is a
slightly different technology. This is where my head starts to hurt. I
can easily comprehend that if you don't have oxygen, you can't burn fuel.
If there's subtleties with boost; how much boost? At what points, eg. atm's
or inches of mercury (bear with us "english" types) does this start
impacting the nefarious and nonspecific issue of performance? More
specifically climb rates, top speed, aircraft ceiling's, etc.
I'm not quibbling, but Emmanuel has made it black and white. Boosted
aspriration. Is it that simple??
--
A.J. Madison PHONE: (508) 490-6972
Stratus Computer Inc.
55 Fairbanks Boulevard INTERNET: a...@sw.stratus.com
Marlboro, MA 01752 OR: Andrew_...@Vos.Stratus.com
freas arthur
ART
Charles K. Scott
a...@octoberfest.sw.stratus.com (Andrew Madison) writes:
> I'm not quibbling, but Emmanuel has made it black and white. Boosted
> aspriration. Is it that simple??
It's actually not quite that simple. The Allison was, contrary to
popular opinion, boosted by a mechanical supercharger. It just wasn't
as effective as was that of the Rolls Royce Merlin.
The bottom line is that supercharging allows the engine to maintain
horsepower (or rather loose less horsepower) beyond 10,000 feet where
normally aspirated engines rapidly trail off because of the ever
decreasing supply of oxygen. In the case of the Merlins vs the
Allisons you can look at it this way; the Merlin's developed greater
horsepower at higher altitudes due to *more effective* supercharging.
Corky Scott
Emmanuel.Gustin
: Emmanuel says that during WWII, the big differentiator between a
: P-51 RR Merlin and a similar but Allison equiped A-36 is that the
: RR Merlin had a mechanical supercharger. I've long known that the Allison
: versus Merlin "Mustangs" were differentiated by high altitude "performance."
: Other posters have implied that its more complex. Two stage supers's
: versus single stage super's. Or even throwing in turbo's which is a
: slightly different technology. This is where my head starts to hurt. I
: can easily comprehend that if you don't have oxygen, you can't burn fuel.
Well, I am becoming confused too...
The V-1710-F3R engine that powered the NA-73X is usually described as
'unsupercharged'. The well-researched work of Green & Swanborough also
describes the V-1710-81 of the P-51A and V-1710-87 of the A-36A as
'unsupercharged'. But when fitted in the P-40N-1, the V-1710-81 is
suddenly claimed to have a single-stage supercharger! I don't believe that
the USAAF would not assign a new dash number models with and without
supercharger.
Of course there is no such thing as "the configuration of the V-1710
engine". The V-1710 was produced in numerous versions. The P-51 and A-26
were powered by F-series engines. A being the original engine as tested in
1932, B the airship version with quick-reverse gearbox, C the older
'normal' version, D the pusher-prop version, and E the version with
extension shaft for the P-39. The F was a thorough redesign. It seems that
some C-series engines already had single-stage mechanical superchargers.
It would be logical to assume that the F-series also had these. Abandoning
it would have been a backward step... Except if this would be considered
unneccessary weight for low-altitude aircraft. Late-war F-models had
two-stage superchargers in a separate housing; these were fitted in the
XP-51J and P-82.
Emmanuel Gustin
Chris Durrant
>Emmanuel says that during WWII, the big differentiator between a
>P-51 RR Merlin and a similar but Allison equiped A-36 is that the
>RR Merlin had a mechanical supercharger. I've long known that the Allison
>versus Merlin "Mustangs" were differentiated by high altitude "performance."
>Whatever that means. "Wings" uses this phrase ad naseum but without any
>detailed substantiation. I also interpret the ABOVE to mean that the
>difference between the two types of aircraft was a simple matter of normal
>aspiration versus super-charging.
>Other posters have implied that its more complex. Two stage supers's
>versus single stage super's. Or even throwing in turbo's which is a
>slightly different technology. This is where my head starts to hurt. I
>can easily comprehend that if you don't have oxygen, you can't burn fuel.
>If there's subtleties with boost; how much boost? At what points, eg. atm's
>or inches of mercury (bear with us "english" types) does this start
>impacting the nefarious and nonspecific issue of performance? More
>specifically climb rates, top speed, aircraft ceiling's, etc.
>I'm not quibbling, but Emmanuel has made it black and white. Boosted
>aspriration. Is it that simple??
The Merlin used a gear driven mechanical supercharger, initially single stage
but later moved to two stage. The Allison (I believe) used an exhaust driven
supercharger (turbocharger) but only single stage therefore its altitude
performance was inferior to the later Merlins. The method of driving the
supercharger is not particularly important, the pressure increase obtained
is. The Merlin changes supercharger gear to high range with a bang at about
10,000 feet. This is done automatically, driven by a barometric capsule.
Whereas modern (small) turbo-charged engines use the extra boost to maintain
sea-level performance at altitude these big military and racing engines used
it to maximise the power output at all stages from overloaded take off up to
combat at 20,000 feet plus.
Chris
---
_______________________________________________________________________________
< Chris Durrant Email: c...@mround.bt.co.uk >
< durra...@bt-web.bt.co.uk >
< >
< Phone: (01473) 647535 >
< +44 473 647535 >
< >
< Fax: (01473) 637523 >
< +44 473 637523 >
_______________________________________________________________________________
Maarten van den Hemel
>Wasn't the Griffon engine used by the Miss Budwieser a V16?
> ART
>
>
No, a RR Griffon engine is also a V12.
Maarten
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Maarten van den Hemel M.VanD...@ET.TUDelft.NL
Telecommunications & Traffic Control Group
Delft University of Technology Delft, The Netherlands
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
I'm but a man The Duke of Wellington, 1813/1815
Geoff Alexander
> > However, Rolls saw the Griffon as a 2500 hp powerplant, they knew
> > they would need more as aircraft auw's increased and you cannot
> > keep on boring and stroking an engine just in the blind hope it'll
> > be alright. Napier had already shown the way forward with their
> > H 24 cylinder engines that culminated with the Sabre.
>
> Nope. With all due respect to your wartime service, (and still regret
> your leaving euro-moto), the Napier was not the way to go. As Tony Rudd
> says in his autobiography, a RR horsepower cost the govt 1 pound sterling.
> A Napier hp cost the govt 3 pounds. Plus their lack of reliability and
> complexity compared to the Merlin/Griffon - RR were correct to use the
> V12s as the standard aero engine, upgrading throughout the war.
>
> regards,
> --
> thos - Thomas Cohen, DoD 1036| "Oh, they all do that..." - Forcycle Engineering
>
Sabre was a superb piece of engineering as was the Dagger before it,
its true there where stories about its unreliability and some of these
where well deservered. From my experience the Sabre needed very careful
handling from cold, it had to be warmed up very carefully indeed or
you risked breaking the sleeve valve drives. It also ran a large diameter
propellor, they even tried them with 17 foot 7 bladed units and with that
size of prop you just cannot play yankee doodle with the throttle without
something up front going bang.
You are correct about it being costly to build, and again it required
skilled fitters to maintain it, when the Bristol Centaurus (an 18 cylinder
2 row radial) became available it was a much cheaper option.
Centaurus to was sleeve valved but ran with huge clearances to combat
siezure of the sleeves and consequent shearing of the drives, a very reliable
engine.
But if you have'nt heard the exhaust beat of a Sabre, even on tickover
then you've missed something.
The Typhoon and its thin winged successor Tempest both with Sabres had no
problems in level flight catching the German V1 flying bombs and flying
alongside them would then use their wingtips to tip them over, much preferred
to using cannons to blow them up with the risk of damage as you then
collected the debris.
My old mother was in the ATA, her log book confirms she delivered 65
Typhoons to the squadrons, she tells a story of one delivery flight
(with the ammunition lockers empty, naturally, the authorities had
enough trouble with my grand father let alone giving mother some bullets)
anyway where was I, mother was trundling along with this Tiffy on a delivery
flight up in Northumberland to some OCU or other when she got bounced by a FW190
on his first pass he knocked some holes in the tail unit and rear fuselage and
mother had no other recourse than open the throttle, suffice to say he
never caught up again, fast woman my mum.
GRA
Olav Hungnes
: Andrew Madison writes:
The Allison V-1710 in the P-51A/A-36 didn't have any form
of supercharging. The V-1710 of the P-38 Lightning was
turbo-supercharged.
--
_______________________________________________________
Olav Hungnes olav.h...@embnet.uio.no
National Institute Phone (+47)22042200
of Public Health FAX (+47)22353605
Oslo, NORWAY
_______________________________________________________
Greg Cotton
OK, I know it's somewhat off topic, but at least it's got the right engine.
Thanks
Greg
Roger Peniston-Bird
A problem with the Merlin in 1940 was the engine cutting out
in a dive. The carburettor had a gravity feed, and with the
negative g created when putting the nose down the engine was
starved of fuel. The Me 109, with fuel injection, could simply
dive away, while a Spitfire pilot would have to half-roll,
losing time, to throw fuel into his engine.
Geoffrey Quill, in his book "Spitfire" (Arrow Books, 1983)
writes (p175):
"The excellent Miss Schilling at the RAE Farnborough... achieved
a substantial amelioration of this problem, but by no means a
full solution. I had no idea what the final answer would be but
was sure I should press very hard for it to be found. (It was,
with the Bendix Stromberg carburettor,but it took a long time."
This prompts me to ask
* Can anyone tell us more about the excellent Miss Schilling?
* How did she ameliorate the problem?
* Did the British not pursue fuel injection or was it
impractical for the Merlin?
* How did the Bendix Stromberg solve the problem?
* Just how long was it before the problem was finally solved?
-------------------------------
Roger Peniston-Bird
PENI...@ADPO1.IAEA.OR.AT
-------------------------------
"A fuel and its Spitfire are soon parted."
Chris Durrant
Roger Peniston-Bird <PENI...@adpo1.iaea.or.at> writes:
>This prompts me to ask
>* Can anyone tell us more about the excellent Miss Schilling?
>* How did she ameliorate the problem?
>* Did the British not pursue fuel injection or was it
> impractical for the Merlin?
>* How did the Bendix Stromberg solve the problem?
>* Just how long was it before the problem was finally solved?
This is one of the oldest Merlin stories around but for thoses who have
not heard it The solution was referred to universally as "Miss Schilling's
orifice" A blanking disk was inserted into the carburettor with a small hole
(the orifice) drilled through. The intention was to restrict the movement
of fuel away from the feed point under negative 'g'.
I suspect that Rolls Royce did not have the expertise in fuel injection
that BMW or Daimler-Benz had so they stuck with what they were good at. I
believe there are power advantages in carburettors which means that fuel
injection is not the universal cure-all. I believe the later carbs were also
referred to as 'pressure carburettors'. Obviously any pressure within the carb
would counteract fuel movement under 'g' but I'm speculating here.
I believe the problem was only with the early aircraft up to around 1941. I dont
think the Mk V suffered from this and certainly not the Mk IX.
Charlie Stone 491 5162
: Another Merlin question, but changing the subject.
: Geoffrey Quill, in his book "Spitfire" (Arrow Books, 1983)
: writes (p175):
: "The excellent Miss Schilling at the RAE Farnborough... achieved
: a substantial amelioration of this problem, but by no means a
: full solution. I had no idea what the final answer would be but
: was sure I should press very hard for it to be found. (It was,
: with the Bendix Stromberg carburettor,but it took a long time."
: This prompts me to ask
: * Can anyone tell us more about the excellent Miss Schilling?
: * How did she ameliorate the problem?
I can't remember the exact details, but I think she came up with the idea
of using a washer as a restrictor in one of the fuel passages/lines
that minimised the problem. The device was referred to as:
`Miss Schillings orifice"
: * How did the Bendix Stromberg solve the problem?
I think that this was a diaphragm carburettor. They dont use a float
chamber. I imagine that the principles would be similar to the
diaphragm carbs used on chain saws that allow operation in any
attitude.
Charlie Stone
Perth, Western Australia.
Conrad Drake
> Another Merlin question, but changing the subject.
>* Can anyone tell us more about the excellent Miss Schilling?
>* How did she ameliorate the problem?
She proposed a perforated rubber diaphram in the float chamber, which stop the
fuel running away.
Rod Clark
>The Allison V-1710 in the P-51A/A-36 didn't have any form
>of supercharging. The V-1710 of the P-38 Lightning was
>turbo-supercharged.
The Allison powered Mustang did have supercharging, but it
was only a single speed single stage supercharger.
The Merlin's fitted to the later Mustangs had two speed
two stage superchargers.
Rod Clark
Melbourne Australia
RCl...@vibuscy.ccdn.otc.com.au
Tony Knight
>
> Chris Durrant (c...@mround.bt.co.uk) wrote:
> : Andrew Madison writes:
>
> : >Emmanuel says that during WWII, the big differentiator between a
> : >P-51 RR Merlin and a similar but Allison equiped A-36 is that
the
> : >RR Merlin had a mechanical supercharger.
> : > I also interpret the ABOVE to mean that the
> : >difference between the two types of aircraft was a simple matter
of normal
> : >aspiration versus super-charging.
>
> : >Other posters have implied that its more complex. Two stage
supers's
> : >versus single stage super's. Or even throwing in turbo's which
is a
> : >slightly different technology.
>
> : The Merlin used a gear driven mechanical supercharger, initially
single stage
> : but later moved to two stage. The Allison (I believe) used an
exhaust driven
> : supercharger (turbocharger) but only single stage therefore its
altitude
> : performance was inferior to the later Merlins. The method of
driving the
> : supercharger is not particularly important,
Oh, but it is important! The "mechanical supercharger" is driven
directly from the engine crankshaft, and so absorbs power from the
engine, in return for the additional power it generates by increasing
the inlet pressure, and hence the charge in the cylinders, which it
does at all engine speeds. The exhaust turbocharger is driven by the
further expansion of hot exhaust gases, thus extending the "power
stroke" of each cylinder and so recovering extra power from the fuel.
It is not mechanically coupled to the engine, and works best at high
engine speeds with greater exhaust velocities. Such an engine could
strictly speaking be defined as a gas turbine, because combustion
takes place outside the cylinders (as well as inside). Superchargers
are fine for big, fairly slow engines, such as my late father's
"blower Bentley", Turbochargers for smaller faster engines, like my
recent Cosworth and present more mundane TD. Put the two
technologies together and you have the Turbo-Compound and Wright
Cyclones, beloved of Connie enthusiasts.
TonyK
Maury Markowitz
> means that fuel injection is not the universal cure-all.
Carburettors act as an intercooler simply by their operation. This does
allow a higher charge to be placed into the engine without additional
intercooling which would otherwise be needed (in other words, it's a free
intercooler). I'm not too sure how much power this can account for, but it's
just one more thing on your side.
The two engines are certainly matches, in a tit-for-tat fashion. The DB's
fuel injection and "ability" to run on lower grade gas was certainly a plus.
The supercharger was NOT as good as the Merlin's though, so the combination
of loss of intercooling from the carburettor, lower quality supercharger and
the tuning to lower performance for the 87 grade fuel all add up to an engine
that gives less power per cubic inch than the Merlin. They both give about
the same power, but (memory here) the Merlin was about 27 litres, and the
DB601 about 35 or so. This allowed the Merlin to be used to create fighters
like the Mustang (admitedly, a number of other items helped in this case!)
who's specific fuel consumption was very low.
On the other hand, the fuel injection system definitely was a serious plus
at higher altitudes, where the Me performed significantly better than the
Spits and Hurricanes. As well, the ability to run on poorer grade fuel
turned out to be a major advantage in many situations where avgas was not
readily available. Then again, the two engines had roughly the same mass, a
testimonial to the ability to shave mass on the DB.
The best way to get a feel for these two is a the Science Museum in London.
The two engines are mounted above one another, so you can compare the two
right there. Quite an interesting display actually, topped for me personally
by the Whittle jet engine... yet, the VERY FIRST jet engine, the original
one, right there on the shelf.
Maury
Matthew Saroff
Some facts comparing mechanical and turbo supercharging:
1) While Turbocharging is far more efficient than mechanical
supercharging, it isn't a free ride. The additional exhaust
back-pressure consumes power. According to Harry Stubbs, who flew B-24s
during the second world war, at full throttle, this amounted to about 200
hp. It should be noted that mechanical supercharging consumes much more
power. BTW, Col. Stubbs (Ret) has a degree in physics. In fact Specific
fuel consumption decreases due to capturing energy that is normally
dumped down the exhaust pipe (basic 3-laws of physics, you don't get
anything for nothing).
2) Because turbos run off pressure DIFFERENTIAL, they are far more
effective at higher altitudes. If you have a mechanical supercharger and
a turbocharger that provide 5 pounds of boost at sea level (psia=15+5=
20psi), at altitude (let's say 1/2 atm pressure) the mechanical blower
will supply about 10psia, and the turbo, which will actually be spinning
FASTER than it would at sea level, would probably be supplying about
15 psia. Until one gets to extremely high altudes or starts running into
the mechanical limits for turbine speed, the turbo supplies essentially
the same pressure. This is what maed the P-38 & P-47 so effective at
altitude.
3) A turbocharged engine will have slower throttle response. In a
mechanical system, the pressure varies directly with engine speed, the
turbo frequently has to catch up. I am currently working with
turbocharged diesels in locomotives, and idle to notch 8 (full throttle)
is in excess of a minute.
4) It is much more difficult to install a turbocharger. All one really
needs to do with a supercharger is to find a place to hang it, and
install plumbing. With a turbo, you have to redesign the exhaust system,
and accomodate a high-speed bearing operating at temps in excess of 1000
degrees. The statement that I have heard is that the Merlin could not be
turbocharged. This probably means that they would have to reverse the
inlet and exhaust valves & manifolds, not a simple proposition.
--Matthew Saroff| Standard Disclaimer: Not only do I speak for
_____ | No one else, I don't even Speak for me. All my
/ o o \ | personalities and the spirits that I channel
______|_____|_____| channel disavow all knowledge of my activities. ;-)
uuu U uuu |
| In fact, all my personalities and channeled spirits
Saroff wuz here | hate my guts. (Well, maybe with garlic & butter...)
Geoff Alexander
cannot ever be the case, in the case of Merlin you had a narrow engine
sheathed in contour hugging cowlings, the is no room left under there
to go faffing around with turbo's without ruining the aerodynamics.
Merlin originally had a single speed centrfigugal impellor super-
charger, with the advent shortly after the start of WW2 of the heavily
leaded Avgas 100/130 Rolls where able to increase the amount of boost
by doubling up on the supercharger with the addition of another
impeelor. Here you have to bear in mind that they hit detonation problems
with the charge igniting in the supercharger, hence the 2 speed 2 stage
supercharger was equipped with an intercooler, this cooled the charge
between stages, in this way Rolls successfully knocked some Merlins
out with +24 lbs boost, at which juncture you where talking serious
horsepower and they where maintaining it at altitude.
Rolls never just turned out an engine, they where thinkers, and they to
wondered about the waste exhaust gasses, not with a view to a turbo-
charger but with a view to using the waste gasses as thrust, they
indulged themselves with the design og the exhaust stacks (12 off)
and it worth looking at old pictures to see just how these developed.
Merlin, like Kestrel before it had initially exhausted straight out of
cylinder head, at 90 degree's to the airflow, gradually it was fitted
with exhaust stubs and these where developed to a fine art.
Similarly in its Spitfire application great attention was paid the the
design of the radiators, they where indeed contributing thrust.
Now with the big hulking radials so beloved of some, these with their
anular exhaust rings and huge diameter exit pipe did nothing, the
American philosphy was entirely different to ours and they by the
limitations of range thought big, plenty of room around for the plumbing
of turbo's, although those big radials did not spin as fast as Merlin
and where way behind Sabre. I do not believe they ever achieved greater
BHP per litre it was just a different approach.
Now, Merlins blower was driven at 10 times engine speed, therefore at
maximum rpm it was spinning at 30.000 revs, yes it was driven off the
crank but you can imagine what would happen if you slammed the throttle
shut with that mass whirling around, so it had a clutch, you still have
to be careful with the throttle has you can bring the revs down but the
blower can still be singing at high rpm and you can get overboosting.
Now when you compare this to a mere car you are in a different ball park,
the mechanical blowers invariably fitted to cars could not have ever
been fitted with an efficient centrifuagal blower, these where the vane type
superchargers and had to have their own lubrication system, those like
the Bentley where drinen directly off the crankshaft and where a particularly
neat installation, I have no doubt whatsoever that you will have noticed the
absense of plumbing and cables on the Bentley and that in your tin can
you probably cannot even see the engine because of it, take your choice
but I doubt the Cosorth will be around in 50 years and the Bentley probably
still will. Back about 10 years or so I heard that Alfa Romeo had reverted
to mechanical blowing, my interest in cars is limited unless it came from
Solihull so I don't know for sure, but I remember thinking thank Christ
someones seen the light.
Talking of Avgas 100/130 reminds me that Sabre needed even more than
that, she had her own brew Avgas 140, so heavily leaded was this it
looked like dark brown ale, and the fumes alone would give you a rash,
for the life of me I cannot remember the boost at which Sabre ran.
You mention the big Cyclones, I assume the R-3350 as went into B29
and Connie, these where rated at 2200 hp which I consider to be short
of Griffon, and they had a lot of problems initially. True they later
went on to knock out around 3300 hp but I think this was with twin turbo's
and water methanol injection Connie was not a cheap aeroplane to operate.
Now take a look at the engine nacelles of Griffon and Cylone.
The US carried on with big piston development after the war, with the
Cyclone R3350 and the P&W R-4360 Wasp Major, apart from developing the
crossover exhaust system for the Canadair DC4M (Argonaut) Rolls where to
ensconced with the new fangled blowlamps to pay much further attention
and piston power went very low key, Merlin overhaul had ceased (just) at
the time of the Argonaut crash at Stockport, the line was reopened for
the crash investigation, this was 1967.
GRA (get me a piston queen, a flight engineer and a navigator and
I'll get you there, SOMEHOW)
Charles K. Scott
Matthew Saroff <msa...@moose.erie.net> writes:
> 1) While Turbocharging is far more efficient than mechanical
> supercharging, it isn't a free ride. The additional exhaust
> back-pressure consumes power. According to Harry Stubbs, who flew B-24s
> during the second world war, at full throttle, this amounted to about 200
> hp. It should be noted that mechanical supercharging consumes much more
> power. BTW, Col. Stubbs (Ret) has a degree in physics. In fact Specific
> fuel consumption decreases due to capturing energy that is normally
> dumped down the exhaust pipe (basic 3-laws of physics, you don't get
> anything for nothing).
I'm a little confused by this. First, how does one know how much
horsepower is lost by the back pressure of turbo supercharging? If the
maximum power is developed *WITH* the turbo supercharger, that means
that without it, it develops less. So how can you tell that this
particular method of supercharging an engine is costing it 200 hp?
Second, you state that "Specific fuel consumption decreases due to
capturing energy". This means that the engine is burning "LESS" gas
with turbo supercharging than without, but then you state that you
can't get something for nothing. But your first statement implies that
you did (better gas milage). Did I miss something?
Sorry about my confusion.
Corky Scott
Matthew Saroff
> In article <Pine.LNX.3.91.950227...@moose.erie.net>
> Matthew Saroff <msa...@moose.erie.net> writes:
>
---snip---
>
> I'm a little confused by this. First, how does one know how much
> horsepower is lost by the back pressure of turbo supercharging? If the
> maximum power is developed *WITH* the turbo supercharger, that means
> that without it, it develops less. So how can you tell that this
> particular method of supercharging an engine is costing it 200 hp?
> Second, you state that "Specific fuel consumption decreases due to
> capturing energy". This means that the engine is burning "LESS" gas
> with turbo supercharging than without, but then you state that you
> can't get something for nothing. But your first statement implies that
> you did (better gas milage). Did I miss something?
>
> Sorry about my confusion.
>
> Corky Scott
>
>
Sorry about the confusion. If you compare a turbocharged and a
non-turbocharged engine running at the same power, say 1000 hp, due to
losses in the system from the turbo, it will consume more fuel. However,
ant full throttle, the turbo will have a lower sfc than the normally
aspirated engine, for example 500 gallons/hour at 2000 non-turboed hp,
and 700 gal/hour at 3000 turbo hp. SFC is in units of gallons per hour
per horsepower.
The 200 horsepower consumed by the turbo is as compared to what one might
get if one were to magically compress said air. It's what happens in
discussions when one has a physics degree and does astrophysics and
cosmology as a faction writer (Col. Harry C. Sutbbs = SF author Hal
Clement, and he qualifies as one of the 4 nicest people on the planet earth.)
My apologies for any typos. I'm doing this on my wife's #@#$&&* Apple
IIc, which doesn't support the ansi editor on my net hookup. My computer
is in the shop.
Rick Jansky
[... text above snipped ...]
: With the final mark of 109, the G version, power had been upped to
I believe that the final mark of the 109 was the 'K'.
[... more text snipped ...]
: To surmise, in the 109 and the FW190, the Germans had 2 superb fighters
: our two where just that fraction better,
My feelings on the "fraction better" would be more to the pilots than
the aircraft, especially late in the war. While during the Battle of
Britain the RAF was flying against many battle hardened veterans
(thanks to the Spanish Civil War) later in the war the Luftwaffe had
neither the time nor the resources to properly train new pilots.
For this reason, IMHO, I would consider the Spitfire, Bf109, FW190,
and P-51 "equals" in terms of Air Superiority capabilites. The edge
that the Allies had was training, training, training.
Flame when ready Griddly ...
______________________________________________________________________
/ /|
+---------------------------------------------------------------------+ |
| | |
| Richard J. Jansky (Rick) rja...@melpar.esys.com Falls Church, VA | |
| | |
| ... Leesburg traffic, | |
| Warrior 4-3-2-5-Victor turning Final, | |
| 3-5 Leesburg ... | |
| |/
+---------------------------------------------------------------------+
Charles K. Scott
the principle of supercharging engines. Unfortunately, that is the
part I UNDERSTAND pretty well. What I was not understanding was how
the horsepower losses of various supercharging systems could be
measured. I've always read that mechnically driven superchargers cost
more in terms of friction losses than did turbo superchargers. The
overall result is more horsepower than the normally aspirated engine
especially at high altitudes but there was a reference by one
knowledgeable poster about how MUCH horsepower a particular turbo
supercharging setup was costing. He said about 200 horsepower. This
is the part I did not understand although this same person kindly
E-Mailed me and explained that engines are just airpumps and that the
friction of running them can be measured by spinning them without the
ignition running and measuring the horsepower it takes to do that. At
least I think that's what he said.
Thanks again to one and all who responded to this question.
Corky Scott
Tony Knight
In article <3iv91i$h...@dartvax.dartmouth.edu>,
> I'm a little confused by this. First, how does one know how much
> horsepower is lost by the back pressure of turbo supercharging? If
the
> maximum power is developed *WITH* the turbo supercharger, that
means
> that without it, it develops less. So how can you tell that this
> particular method of supercharging an engine is costing it 200 hp?
>
> Second, you state that "Specific fuel consumption decreases due to
> capturing energy". This means that the engine is burning "LESS"
gas
> with turbo supercharging than without, but then you state that you
> can't get something for nothing. But your first statement implies
that
> you did (better gas milage). Did I miss something?
The only source of energy here is the fuel. Without any form of
forced induction (boost), a certain mass of fuel-air mixture is
delivered to the cylinder, is ignited, burned, and expands, producing
mechanical energy as it drives the piston down. The trick is to
extract as much energy as possible from the fuel, by achieving
complete combustion and maximum expansion, before the exhaust stroke
begins. With boost, from a mechanical supercharger, or from an
exhaust turbocharger, a geater mass of mixture is delivered, and at
higher pressure, so there is potentially more energy to be obtained.
In a turbocharged engine the exhaust gases drive the turbine, which
then compresses the mixture. Part of the expansion of the burning
gases (combustion) takes place outside the cylinder as the gases pass
through the turbine. Thus it is possible to extract more energy
from the hot gases that would otherwise simply be ejected from the
exhaust stubs. The "loss of power" discussed earlier must simply be
that power that could be obtained, at the same boost pressure, from
mechanical supercharging compared with that available from a
turbocharger.
As has been pointed out earlier, a supercharger loses efficiency at
higher altitudes (hence 2-stage superchargers with gears and
clutches, speed changing at about 15,000ft) whereas a turbocharger,
whose efficiency depends on the differential between inlet and
exhaust pressure, works better at high altitudes.
Constellation captains used to warn passengers about the change in
engine note due, presumably, to the changing of supercharger speed.
This used to happen about 1/2hour into a flight, about 15,000ft?
When Typhoons became ground-attack aircraft some of them were
modified to disable the second supercharger speed. Their operational
ceiling then became, yes, 15,000ft.
TonyK
Mike Campbell
In article <NEWTNews.1659.793...@tony.henleymc.ac.uk> Tony writes:
> Oh, but it is important! The "mechanical supercharger" is driven
> directly from the engine crankshaft, and so absorbs power from the
> engine, in return for the additional power it generates by increasing
> the inlet pressure, and hence the charge in the cylinders, which it
> does at all engine speeds. The exhaust turbocharger is driven by the
> further expansion of hot exhaust gases, thus extending the "power
> stroke" of each cylinder and so recovering extra power from the fuel.
> It is not mechanically coupled to the engine, and works best at high
> engine speeds with greater exhaust velocities. Such an engine could
> strictly speaking be defined as a gas turbine, because combustion
> takes place outside the cylinders (as well as inside).
Whoa - there is no extra combustion in a turbo-charger! It is energy
recovery sure, but only from the velocity and heat of the exhaust
gasses.
Both super- and turbo- chargers work by driving a compressor in the
inlet side of the engine to push more air into the cylinder. More air
means more fuel can be burnt (due to more oxygen), so you get more
power. Nothing more.
Superchargers
> are fine for big, fairly slow engines, such as my late father's
> "blower Bentley", Turbochargers for smaller faster engines, like my
> recent Cosworth and present more mundane TD. Put the two
> technologies together and you have the Turbo-Compound and Wright
> Cyclones, beloved of Connie enthusiasts.
The Turbo-compounds are not a cross between turbo- and super-charging!
The turbines on the exhaust on these engines drive onto the
crankshaft, providing extra power directly. They do not compress the
incoming air. Well at least not according to the FAA A&P Powerplant
handbook :-)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Mike Campbell, + A cuspide corona
Blenheim, + -From the spear [comes] a crown
New Zealand +
mi...@aloysius.equinox.gen.nz + (Latin proverb)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Ken Fischer
[snip]
: knowledgeable poster about how MUCH horsepower a particular turbo
: supercharging setup was costing. He said about 200 horsepower. This
: is the part I did not understand although this same person kindly
: E-Mailed me and explained that engines are just airpumps and that the
: friction of running them can be measured by spinning them without the
: ignition running and measuring the horsepower it takes to do that. At
: least I think that's what he said.
Perhaps he meant to say that geared superchargers are
just air pumps, and the horsepower required to turn them can
be determined by either running the supercharger alone, or by
driving the engine aassembly externally with or without the
supercharger to see how much power is required to drive each,
as the up gearing might add to the power loss.
kfis...@iglou.com Internet Gateway Louisville
Andrew McNeil
r...@h4gate.ssw.melpar.esys.com (Rick Jansky) writes:
> My feelings on the "fraction better" would be more to the pilots than
> the aircraft, especially late in the war. While during the Battle of
> Britain the RAF was flying against many battle hardened veterans
> (thanks to the Spanish Civil War) later in the war the Luftwaffe had
> neither the time nor the resources to properly train new pilots.
>
> For this reason, IMHO, I would consider the Spitfire, Bf109, FW190,
> and P-51 "equals" in terms of Air Superiority capabilites. The edge
> that the Allies had was training, training, training.
Yes, I agree that pilot training is almost always the deciding factor,
and that it is often ignored. Look at the Israeli wars, or the Gulf
war:
sure the planes were good, but the 20 to 1 or greater kill ratios are
the result of training.
This said, the Mustang had one huge advantage that CANNOT be made up
for
with pilot skill: range. You could have Adolf Galland flying a
spitfire
on escort from UK to Berlin, but he'd still run out of gas!
I hate to admit this 'cuz I am a fan of radial engines, and like the
P-47 better, but it didn't have the range (atleast until the P-47N
but that is another story! . . . )
Andrew McNeil 'Vincere vel mori' *****************
* These are my
'Every time the legislature meets every man's * opinions, not
life, limb, & property are in danger' * my employers
Thomas Jefferson *****************
Robert Virding
In article <3jfn0b$h...@newsgate.sps.mot.com>, r16...@email.mot.com (Andrew McNeil) writes:
..
|>This said, the Mustang had one huge advantage that CANNOT be made up
|>for
|>with pilot skill: range. You could have Adolf Galland flying a
|>spitfire
|>on escort from UK to Berlin, but he'd still run out of gas!
|>
|>I hate to admit this 'cuz I am a fan of radial engines, and like the
|>P-47 better, but it didn't have the range (atleast until the P-47N
|>but that is another story! . . . )
I remember reading somewhere that later Spitfire did/could have large
fuel tanks and, hance, could have been used for long range escort
instead of the Mustang. Is this true? If it is why weren't they used?
Some earlier articles in this thread (Merlin engines) mentioned that
the Packard built engines didn't have the same high quality as the
Rolls engines. Why did they do this? Is/was this typical of other US
built engines?
--
Robert Virding Email: r...@erix.ericsson.se
Computer Science Laboratory Tel: +48 8 727 34 52
Ellemtel Telecommunications Systems Laboratories
Box 1505, S-125 25 ÄLVSJÖ, SWEDEN
Geoff Alexander
What you say about range is true, but the P51 was designed with a
different concept in mind, Spitfire and Hurricane date from the
early 30's and had only one concept in mind 'air superiority'; the
thought of flying escort for bombers had'nt even occurred.
In the event there was no need to fly escort, Bomber Command flew
at night.
Pilot training, agreed we never dropped our standards and in the latter
stages of WW2 the Germans where putting kids in the cockpit, but at the
time that it mattered in 1940 their pilots had the edge in experience.
Our pilots, the so called 'Few' where a few regulars and the University
Air Squadrons, apart from a little Colonial Policing there was precious
little experience around, yet the aircraft pulled it off when it mattered
most. Like Spitfire the P51D runs courtesy of Merlin, it was not a special
version that ran on fumes, the specific fuel consumption is the same
indeed I can assure you the Packard might consume more, hence a P51 on full
tanks does not have the same performance as a Spitfire on full tanks
due to the excess baggage of fuel. Spitfires range could be increased with
the use of drop tanks and indeed was it not a Spitfire with a belly tank that
dropped Baders spare legs.
Alison engined North American NA 73 Apache (Mustang was the RAF designation)
known as the P51 pursuit in the USAAC where over here at the time of the
Spitfire III, tankage was 170 gallons compared to the Spitfires 85.
So what did they do?
The later development with the Merlin, the P51D had its tankage upped
to 290 US gallons but now you have to compare it to a Spitfire XIV with
a 2000hp Griffon up front, again at 140 gallons the Spitfire lags for
range but then look at the firepower, P51 always lagged behind with 6
5 calibre machine guns as opposed to 20mm Hispano cannons Spitfires had
up their shirts.
Range or not, there was no way P51 could give anything like total cover
for the daylight missions flown by the B17's, flying out of East Anglia
they could only stay with them for 350 miles and go back later for the
remnants, had the US bombers been equipped and trained for night flying
even that would not have been needed.
You may care to recall Bomber Commands first visit (by Night) to Berlin,
the following morning when the Krauts came up for air they got knocked
about by Mosquitoes who having dropped their 4000 pounders then opened
the taps and left the Luftwaffe in the dust.
Just think of that, a 4000 pounder, that was all a B17 could carry over
that distance and the Mossie needed no escort agency, thats what you call
air superiority.
GRA
Paul Jonathan Adam
My personal opinion is that the P-51 and Spitfire are fundamentally different
aircraft. A Spitfire can take off and engage opponents coming over the
perimeter fence: the P-51 was damn near unflyable with full fuel. But burn
off a lot of that fuel and you had a superb fighter: I'd give the Spitfire
an edge in a close fight, but the point could well be this: the P-51 can go
reach out and touch the Spit, the Spit can beat the Mustang when it's
overhead (just!) but can't take the fight to the P-51.
If you want a local-defence fighter vectored by radar, relatively short
range but incredible dogfighting performance, get Spitfires. If you need to
fly a _long_ way before you fight, get P-51Ds. My opinion on the armament is
that four 20mm beat six .50s, but two 20mms and four .303s are a tie or even
slightly inferior.
And with liquid-cooled engines neither made brilliant mudbeaters: the P-47
was a good fighter but an incredible ground attack aircraft. My own opinion
is that World War 2 produced so many superb aircraft that deciding which is
'the best' is futile: pick each mission in turn and then choose a winner.
Want a controversy? My votes go to the Ju-88 and the Il-2. Asbestos on!
--
When you have shot and killed a man, you have defined your attitude towards
him. You have offered a definite answer to a definite problem. For better or
for worse, you have acted decisively.
In fact, the next move is up to him.
Paul J. Adam pa...@jrwlynch.demon.co.uk
Charles K. Scott
Geoff Alexander <ccz...@szn1.agric.nottingham.ac.uk> writes:
> but then look at the firepower, P51 always lagged behind with 6
> 5 calibre machine guns as opposed to 20mm Hispano cannons Spitfires had
> up their shirts.
Well, one of your best, Clive Caldwell, thought that six .50 caliber
machine guns was a superior armament to the standard Spitfire weapons
and he sorely missed them when flying Spitfires, so he said.
> Range or not, there was no way P51 could give anything like total cover
> for the daylight missions flown by the B17's, flying out of East Anglia
> they could only stay with them for 350 miles and go back later for the
> remnants
This is innaccurate. The Mustangs provided full coverage all the way
to any target in Germany and then had the fuel reserves to provide
combat and still come home. When the B-17's shuttled to Russia all the
way across Germany and out the other side, the Mustangs went with them.
The range of the Mustangs was 1200 miles in most cases, not 900.
, had the US bombers been equipped and trained for night flying
> even that would not have been needed.
You are repeating an old and disprooved notion. The Luftwaffe's
strength was it's day fighter and bomber force. In order to destroy
that, the battles had to be fought during the day. Had Germany been
attacked only with night bombers, the day air force would have been
left fully intact and operational for the invasion.
> You may care to recall Bomber Commands first visit (by Night) to Berlin,
> the following morning when the Krauts came up for air they got knocked
> about by Mosquitoes who having dropped their 4000 pounders then opened
> the taps and left the Luftwaffe in the dust.
Can you provide specifics? What types of aircraft attempted
interception, if any?
> Just think of that, a 4000 pounder, that was all a B17 could carry over
> that distance and the Mossie needed no escort agency, thats what you call
> air superiority.
This is comparing apples to oranges. The B-17 was a heavy bomber
designed in 1935 that had four engines and armor plating for each. It
also carried armor in places to protect the crew. It also carried 13
heavy machine guns, 6 of which were in heavy powered turrets and 600 to
1000 rounds of ammo for each. All this weighs a lot and subtracts from
the bomb load. But it was necessary for bomber protection.
Finally let me repeat that one of the primary objects of the air war
against Germany was to destroy the Luftwaffe. This could only be done
during the day. This meant that the fighters had to be lured to combat
so that the escorting fighters could get to them. This means DAY
bombing, not night. This means bombers that the Germans see as a
threat to their war economy not fast relatively solitary bombers that
basically harrassed the German population.
Finally, a few Mosquitos carrying one 4,000 lb each bomb did not
constitute a huge threat to the German industry. If large numbers of
them had been built and assembled for bombing raids I guarantee that
the Germans would have produced high flying intercepters that would
have had a field day against these unarmed and therefore unprotected
aircraft. They could have simply flown in formation with them and
potted them one by one. Looks like another job for the Mustang. :-)
In my opinion. Corky Scott
Geoff Alexander
>
>
> In article <3jfn0b$h...@newsgate.sps.mot.com>, r16...@email.mot.com (Andrew McNeil) writes:
> |>This said, the Mustang had one huge advantage that CANNOT be made up
> |>for
> |>with pilot skill: range. You could have Adolf Galland flying a
> |>spitfire
> |>on escort from UK to Berlin, but he'd still run out of gas!
> |>
> |>I hate to admit this 'cuz I am a fan of radial engines, and like the
> |>P-47 better, but it didn't have the range (atleast until the P-47N
> |>but that is another story! . . . )
>
> I remember reading somewhere that later Spitfire did/could have large
> fuel tanks and, hance, could have been used for long range escort
> instead of the Mustang. Is this true? If it is why weren't they used?
Spitfire could and indeed carry drop tanks, the emphasis on drop, when
empty they where discarded so as not to compromise aircraft performance.
After the Battle of Britain fighter command engaged itself with the so
called fighter sweeps over France and the low cpuntries. The range by the
use of drop tanks was increased and they went out and shot up anything
that moved. Bear in mind there was never any requirement for our fighters
to fly on escort duty. Bomber Command flew by night, the last thing they
wanted where stray fighters around. Our fighters where positioned as close
to the enemy as we could get them, at Tangmere any closer and they'd have needed
floats, they got airborn when the Luftwaffe where en route and got stuck in,
they had 90 mins duration, more than anything the Germans could send
and after intercepts went back and refueled. Initially in WW2 we where not
the aggressors, but we did not have the production capacity here, we
where always woefully short of hardware, hence came about the lease/lend policy
of hiring US equipment.
> Some earlier articles in this thread (Merlin engines) mentioned that
> the Packard built engines didn't have the same high quality as the
> Rolls engines. Why did they do this? Is/was this typical of other US
> built engines?
> --
> Robert Virding Email: r...@erix.ericsson.se
> Computer Science Laboratory Tel: +48 8 727 34 52
> Ellemtel Telecommunications Systems Laboratories
> Box 1505, S-125 25 ÄLVSJÖ, SWEDEN
>
The US had learned early about mass production, churn things out like
peas in a pod, we went in for hand finishing, very time consuming.
You may or may not have heard of that infamous duel between the boss
of Chrysler and Charles Weymann, in which the bet was that the American
car would beat the daylights out of a Hispano Suissa. The Chrysler ran
its big ends in the race and the yank claimed it was only them hand scraped
bearings of the Hispano that did it. Similarly Rolls went in for hand
fitting, Mr Gadsby of Derby tells me it took him 2 days to scrape and
blue the supercharger end covers, Packard stuffed a bloody gasket in there.
The oil and water pump quill drives where also productionised, for sheer
quality the genuine article is way ahead, trouble is they could'nt
produce enough, they never did either. The US took it on, knowing it was
a little gem of an engine and would improve P51's performance at a stroke.
They also twigged they could flog them back to us.
The US radials around at that time, Twin Wasp and Cyclone are good engines,
not in a Merlins league for quality engineering or producing horses,
more like ponies. But they where economical and reliable, they could also
rumble along with a cylinder shot off; they are typically agricultural
in their construction which is why so many are still running.
Merlins nowadays are a long way from having been overhauled by Rolls,
most in my opinion are death traps, about 3 years back a man with more
money than ability bought a Spitfire and it killed him, the crank had
broken. This is unheard of, but I noted wryly that the engine had been
overhauled by a firm in the UK and they had cocked up the radius where the
crankpin meets the crankweb. Thats the trouble with computer controlled
machine tools, they can't read.
On this tack its worthy of noting that we did'nt have socket sets at
this time, Merlins toolkit is devoid of sockets. I am informed by
those in a position to know that the first socket sets seen over here
came with P&W Wasp engines when the decision was taken to put those
engines in the Miles Master trainer thereby relieving Bristol of the
necessity to produce the Mercury; thus allowing them to get on with
the Hercules. Mind you all the socket sets in the world would'nt get the
inner plugs out of a Merlins block, try that when the beggars hot.
GRA
Charles K. Scott
JE...@dairyho.demon.co.uk ("John E.G. Sunderland") writes:
> OK, I accept that the B17 was designed as a 'heavy', but the fact remains that
> it still took a 4-engined bomber carrying a crew of 10 (?) to carry the same
> bomb-load as the mosquito with a crew of 2 and 2 engines. When first used the
> mosquito could outrun ALL German fighters (up to the FW190-D I believe)
When first used it was an unarmed reconnaissance aircraft. This means
no bombs or cannon to lug around. Stripped down, unarmed PSRU
Spitfires also could outrun German intercepters. These were not
offensive aircraft, they could not in and of themselves cause any
direct harm to the German war effort other than provide confirmation of
strikes and provide targeting info.
> While not wishing to denigrate the efforts of the USAAF in WWII in any way, had
> the mosquito been produced in suitable numbers it could have done a lot more
> damage for far fewer losses than the B17s, while using up less of the war
> materiel (fuel/ammunition) for the same results as achieved by the USAAF. It
> also did not require escort under any circumstances. Also, my opinion is that
> had more of these aircraft been available, the war effort against the luftwaffe
> would have been better served by US fighter sweeps similar to those carried
> out by the RAF later in the war. Using the longer range of the P51 to carry
> the air battle deep into occupied territory and Germany, these sweepscould have
> first removed a large proportion of the German fighter arm, so opening up the
> skies to the B17s and the RAF for daylight raids against industry and German
> bomber bases.
Again, this presupposes that the Germans would have just sat still and
let this occur. The German military showed great talent in modifying
existing weapons or manufacturing new ones to effectively counter
Allied offensive weapons. The use of aerial rockets against the bomber
formations is but one example. As I said in another posting, had the
Mosquito's been available in larger numbers and used in mass formations
to attack Germany the Germans *would* have countered. They always did.
Also, flying singly over Germany in a stripped down unarmed
reconnaissance airplane is not the same thing as flying loaded down
with bombs in formation with a bunch of other airplanes. Formation
flying requires that all aircraft have the ability to speed up to
maintain position, this means that none of the airplanse are actually
at full speed so a mass formation will necessarily fly at slower speeds
than individual non-formated aircraft. Slow enough to make the
difference between being intercepted and not being intercepted.
Now, as to the effectiveness of fighter sweeps. Fighter sweeps only
work if the enemy comes up to fight. If the enemy chooses not to fight
then fighter sweeps just burn up gas and tire out pilots. The Germans
knew this. The standing orders for JG26 were to engage and attack
enemy bombers only if they could do so without loosing too many
fighters in the interception, fighters were to be ignored. Thus the
intercepts against the "Circusses" in 41 and 42 were lead only by
highly experienced leaders like Adolph Galland who could and did
intercept only when the escorting fighters were out of position. One
pass and away was the German fighter dictum during this period (source
JG26). That kind of intercept is almost impossible to prevent which
the British fighter pilots discovered. Galland lead only as many
airplanes as he could effectively control and they struck quickly, in a
high speed dive and sped away to safety. They engaged the escorting
Spitfires only if advantageous to them. They might have been there
watching each time the "circus" arrived but they did not attack each
time. Fighter sweeps, those operations involving only British
fighters, often were completely ignored.
Flying over enemy territory in a fighter without engaging the enemy
aircraft and downing them at rates greater than you suffer should not
be considered a victory, in my opinion. Shortly after Doolittle took
over (after deep discussions with the Allied high command which needed
to have the skies clear of German aircraft for the coming invasion) he
ordered an end to the useless fighters sweeps then in vogue with the US
fighters. He looked at a sign hanging over the entrance to the fighter
group headquarters which said "The duty of a fighter is to protect the
bombers" and said "Take that down and put a sign up that says, 'The
duty of a fighter is to destroy enemy fighters'" (source: "To Command
the Sky"). Fighter sweeps were halted and the bombers were used as
bait to draw the enemy fighters onto the jaws of the escorting
fighters. Needless to say, the bomber guys didn't like this turn of
events and said so. But it was the beginning of the end for the
Luftwaffe.
Corky Scott
Geoff Alexander
>
>
> My personal opinion is that the P-51 and Spitfire are fundamentally different
> aircraft. A Spitfire can take off and engage opponents coming over the
> perimeter fence: the P-51 was damn near unflyable with full fuel. But burn
> off a lot of that fuel and you had a superb fighter: I'd give the Spitfire
> an edge in a close fight, but the point could well be this: the P-51 can go
> reach out and touch the Spit, the Spit can beat the Mustang when it's
> overhead (just!) but can't take the fight to the P-51.
>
8 .303 browning machine gunes would knock the living daylights out of
an Allison engined P51, (confess I've never flown behind the Alison).
P51D/E with the dorsal fillet are different kettles of fish.
You cannot compare them to the early 8 gun Spits, more like you have
to compare them to the Mk16 which has a Merlin and clipped wings for
better roll rate at low altitude. Here the Mk 16 is sporting 2 20mm
cannons ans 2 .5 calibre Brownings. Cannons are superior to machine
guns when it comes to ripping you apart. Even P51 could not carry the
93000 rounds of Lancaster so I assume you had a few seconds worth.
Thats all a fighter pilot has, none of this John Wayne rubbish of guns
that melt after 8 hours shooting, more like 20 seconds.
However Spitfire 16 had the standard Merlin Spit 85 gallon tank plus a 66
gallon tank, thats er er 151 gallons, against 201 imp gallons of the
Mustang, that in round terms on a weak mixture at cruising boost is an
hours flying, 50 mins at top wack.
That is all that the Spit lacked, assuming overloads then there is no reason
the Spitfire could'nt carry the same tanks, but, there was never the requirement
for them to do so.
By this time the Griffon Spits where in, 2000hp up front, 4 20mm cannons
available as standard or with clipped wings and 8000lbs fully loaded
against the 10000 lbs loaded of P51. Guess who's going to get his backside shot off.
> If you want a local-defence fighter vectored by radar, relatively short
> range but incredible dogfighting performance, get Spitfires. If you need to
> fly a _long_ way before you fight, get P-51Ds. My opinion on the armament is
> that four 20mm beat six .50s, but two 20mms and four .303s are a tie or even
> slightly inferior.
>
> And with liquid-cooled engines neither made brilliant mudbeaters: the P-47
> was a good fighter but an incredible ground attack aircraft. My own opinion
> is that World War 2 produced so many superb aircraft that deciding which is
> 'the best' is futile: pick each mission in turn and then choose a winner.
>
good as Spitfire, remember Spitfires development never ceased, it was relentless
and culminated in Spiteful, but by then the jets where up and running.
> Want a controversy? My votes go to the Ju-88 and the Il-2. Asbestos on!
>
Gimme a chance
> --
> When you have shot and killed a man, you have defined your attitude towards
> him. You have offered a definite answer to a definite problem. For better or
> for worse, you have acted decisively.
> In fact, the next move is up to him.
>
I gather you have been educated, I always figured kill the grunt quick
before he kills me, mind you I have compassion, should I have been
mistaken I would have said sorry as I am. Trouble with a battle zone is that
you have no time for thinking. do it before you get done.
Survivor
> Paul J. Adam pa...@jrwlynch.demon.co.uk
Mike Campbell
In article <3ji6m4$r...@unicorn.nott.ac.uk> Geoff writes:
> What you say about range is true, but the P51 was designed with a
> different concept in mind, Spitfire and Hurricane date from the
> early 30's and had only one concept in mind 'air superiority'; the
> thought of flying escort for bombers had'nt even occurred.
True.
> In the event there was no need to fly escort, Bomber Command flew
> at night.
Bzzt - sort of true, but the philosophy when the Spitfire and
Hurricane were being designed was "The Bomber Will Always Get Through"
- hence no need for escorts.
The British bombers at the start of the war were not specifically
equipped or designed for night operations!
> You may care to recall Bomber Commands first visit (by Night) to Berlin,
> the following morning when the Krauts came up for air they got knocked
> about by Mosquitoes who having dropped their 4000 pounders then opened
> the taps and left the Luftwaffe in the dust.
Really??? You'll have to provide serious refernces - numbers, A/C
types to justify this one!
> Just think of that, a 4000 pounder, that was all a B17 could carry over
> that distance and the Mossie needed no escort agency, thats what you call
> air superiority.
Mosquito's could only operate like this by night. By day they would
have been toast. By night they were no more capable of destroying
German Industry than any other part of Bomber Command. At leat the B-
17 raids (with 4000lb loads) to Berlin got the Luftwaffe up to fight,
and allowed the escorts to shoot it down!
Petteri Kihlberg
> I remember reading somewhere that later Spitfire did/could have large
> fuel tanks and, hance, could have been used for long range escort
> instead of the Mustang. Is this true? If it is why weren't they used?
Some Spitfires had a extra fuel tank behind the pilot. It changed the
balance of the plane and made it longitudially (spelling) unstable.
The extra tank was used mainly for ferry flights.
--
Petteri Kihlberg | "Many that live deserve death. And some that die |
pet...@clinet.fi | deserve life. Can you give it to them? Then do not |
UK AW5266 Zombie | be too eager to deal out death in judgement." -G. |
US (CRIS) AW4151 |______________________________________________________|
Charles K. Scott
> > You may care to recall Bomber Commands first visit (by Night) to Berlin,
> > the following morning when the Krauts came up for air they got knocked
> > about by Mosquitoes who having dropped their 4000 pounders then opened
> > the taps and left the Luftwaffe in the dust.
Once in a while if you read a lot like I do, you get lucky. My latest
nightly read is a book entitled "Wings of War" by Laddie Lucas who flew
fighters for the British during WWII. The book is a compilation of a
number of articles written by ex fighter pilots, bomber pilots and
other aircraft people some on the ground and some in command. It was
from this book that I found the Clive Caldwell blurb. Also, it turns
out, there is an article written by one of the actual participants of
that raid on Berlin mentioned by Geoff. The event, it appears, was a
little different in actual deployment than described. The description
of that first attack on Berlin by one of the planners, Air Chief
Marshal Sir Wallace Kyle follows. I'm going to have to abridge it a
bit because it's pretty long for a network posting:
"On Saturday 30 January 1943, Mosquitoes of 105 and 139 Squadrons,
based at Marham, in Norfolk, where I was then Station Commander, made
the first daylight bombing raid on Berlin. The attacked twice that
day, at 1100 and 1600 hours.
We were operating reqularly by day at low level against targets in
occupied Europe with occasional, deeper penetrations into Germany
itself. We were independent of the main bomber force and although we
had, of course, been given a general operational directive, the
detailed planning, including the selection of specific targets and the
timing of the raids, was left to me and the squadron commanders.
Now and then, however, we would be given a particular task by
Bomber Command Headquarters, and these were usually prompted by special
intelligence.
We operated largely in heavily defended areas, but, on the whole,
the losses were relatively light. The high speed and manoeuvrability
(sic) of the Mosquito was a very important factor and, in many
instances, it was the first attack on the target and , more often than
not, we went in at dusk and withdrew at low level in the gathering
darkness. (I left this in to show that the Mosquito's were not
exclusively flown at high altitude)
It was about 1500 hours on 29 January when I received a telephone
call from Group Captain Elworthy ... then Group Captain Operations at
Bomber Command. I had just stood both squadrons down after a very
heavy week. He told me that the C-in-C wanted Mosquitoes to attack
Berlin the following day at 1100 hours precisely, when Gšring was
scheduled to speak at an open-air mass rally. What did I think?
This was, to put it mildly, rather a surprise, not so much because
of the target (Berlin), but because of the timing which would restrict
our tactical freedom of action. It meant that we would be exposed to
fighter attack both during penetration and again, on withdrawal when
the advantage of surprise had gone. I said that we would be lucky to
get away without severe casualties. Elworthy, who knew the operational
form well enough, agreed and offered to represent this to the C-in-C.
Before long, he came back to confirm that we were to go. There
followed a pause, 'You haven't heard all of it yet. We want you to
attack again at 1600 when Goebbels will be speaking at a similar
rally.'
We decided to send three aircraft from 105 Squadron on the morning
raid and three from 139 in the afternoon.
We thought we could get away with the penetration phase by staying
at low level until the last moment before climbing to 25,000 feet for
the bombing run. The route chosen was pretty well direct and we were
able to stay under radar cover as far as Honover. Withdrawal was to be
by diving at maximum speed to low level, heading for Norway, without
too much regard for Swedish air space, and then directly back to base.
This was about the limit of endurance for the Mk IV Mosquito in the
low-high-low profile.
The morning attack went exactly to plan and the bombs were dropped
at precisely 1100 hours. Even the heavens were on our side because, at
the very last moment, after Sismore had told Reynolds it would have to
be an ETA release, he spotted a hole in the otherwise complete cloud
cover. It was plumb over Berlin and they cold see the lakes and
Spandau. The bombs hit the northeast area of the city. The tactics
had worked and all aircraft returned safely. It was a superb piece of
accurate flying and navigation. (We had no radar aids then.)
We were apprehensive about the afternoon attack because the
defences had obviously been stirred up. We certainly didn't think we
should follow the same penetration and withdrawal routes. After a lot
of discussion with the crews we decided on the simple solution of
reversing the routes. We calculated the run in would have mximum
surprise, especially using the fringe of Swedish air space; and most of
the withdawal phase would be in dusk conditions over Germany and
Holland at low levels.
Sure enough, we got away with the penetration, but the flak was more
intense and Squadron Leader Darling was picked off after bombing."
So contrary to popular myth, the attack was not a high level approach
to the target area whereupon they "then opened the taps and left the
Luftwaffe in the dust." It was a carefully planned and executed low
level penetration with pop up to bombing altitude then a maximum speed
dive back down to the ground for the return. And a Mosquito was lost
to flack.
Corky Scott
Tony Knight
In article <3jq018$a...@dartvax.dartmouth.edu>,
> Now, as to the effectiveness of fighter sweeps. Fighter sweeps
only
> work if the enemy comes up to fight. If the enemy chooses not to
fight
> then fighter sweeps just burn up gas and tire out pilots. The
Germans
> knew this. The standing orders for JG26 were to engage and attack
> enemy bombers only if they could do so without loosing too many
> fighters in the interception, fighters were to be ignored.
In "Most Secret War", R.V.Jones, the author tells how the RAF experts
thought that the Germans had devised a radar system able to detect
bombs inside attacking bomber formations. They reached this
conclusion because fighter sweeps were unopposed, whereas bombers
(accompanied by fighters) were strongly opposed by German fighters.
How could the defenders tell the difference between "armed" and
"unarmed" formations?
Jones asked "at what speed are the sweeps flown?"
Collapse of "experts"!
TonyK
Steven Vincent
>In article <794769...@dairyho.demon.co.uk>
>JE...@dairyho.demon.co.uk ("John E.G. Sunderland") writes:
>When first used it was an unarmed reconnaissance aircraft. This means
>no bombs or cannon to lug around. Stripped down, unarmed PSRU
>Spitfires also could outrun German intercepters. These were not
>offensive aircraft, they could not in and of themselves cause any
>direct harm to the German war effort other than provide confirmation of
>strikes and provide targeting info.
Mosquito Bombers could outrun all german fighter when equipped with
a full bomb load at their time of introduction. This bomb load
was originally 2000lb not the later 4000lb.
>> the air battle deep into occupied territory and Germany, these sweepscould have
>> first removed a large proportion of the German fighter arm, so opening up the
>> skies to the B17s and the RAF for daylight raids against industry and German
>> bomber bases.
Fighter Sweeps only do damage if the opposition comes up and contests
the airspace or the Sweep aircraft expend ordanance on air-ground.
>again, this presupposes that the Germans would have just sat still and
>let this occur. The German military showed great talent in modifying
>existing weapons or manufacturing new ones to effectively counter
>Allied offensive weapons. The use of aerial rockets against the bomber
>formations is but one example. As I said in another posting, had the
>Mosquito's been available in larger numbers and used in mass formations
>to attack Germany the Germans *would* have countered. They always did.
While I agree that we would have been faced with an Escalation in
terms of Speed rather than Armament I also think that the High
speed bomber that does not expend payload on other defences
would have been a very successful and economic weapon. Yes
by 1944 we would have had to come up with a faster replacement
than the Mosquito BUT the 109 would have been left in the dust
and we would have forced the development of the 162 and 262
Jet fighters at a pace that would have made their entry into
service an even bigger hazzard to the Luftwaffe pilots.
> Also, flying singly over Germany in a stripped down unarmed
>reconnaissance airplane is not the same thing as flying loaded down
British Mosquito Squadrons flew in formation on all there raids.
Normally only in Single squadrons or wings. Noway was it an unarmed
mosquito squadron that first bombed Berlin in daylight AND timed
that raid with a speach by Goring saying that the RAF could never
bomb Berlin. The real hit here was that the sound of the Air Raid
sirens followed by the explosions of the bombs could be heard in
the background of Goring's speach.
>with bombs in formation with a bunch of other airplanes. Formation
>flying requires that all aircraft have the ability to speed up to
>maintain position, this means that none of the airplanse are actually
>at full speed so a mass formation will necessarily fly at slower speeds
>than individual non-formated aircraft. Slow enough to make the
>difference between being intercepted and not being intercepted.
>Flying over enemy territory in a fighter without engaging the enemy
>aircraft and downing them at rates greater than you suffer should not
>be considered a victory, in my opinion. Shortly after Doolittle took
>over (after deep discussions with the Allied high command which needed
>to have the skies clear of German aircraft for the coming invasion) he
>ordered an end to the useless fighters sweeps then in vogue with the US
>fighters. He looked at a sign hanging over the entrance to the fighter
>group headquarters which said "The duty of a fighter is to protect the
>bombers" and said "Take that down and put a sign up that says, 'The
>duty of a fighter is to destroy enemy fighters'" (source: "To Command
>the Sky"). Fighter sweeps were halted and the bombers were used as
>bait to draw the enemy fighters onto the jaws of the escorting
>fighters. Needless to say, the bomber guys didn't like this turn of
>events and said so. But it was the beginning of the end for the
>Luftwaffe.
It does not matter how many fighters you shoot down UNTIL you have
guys on the ground. The studies performed after the war showed that
the Mosquitos had droped more bombs (weight) per Aircrew casualty
than any other allied aircraft. Most RAF Mosquito squadrons were
operating by day and did not need a large defensive formation. They
bombed from lower and scored higher accuracy than US Mediums at
ranges far beyond the reach of fighter bombers. The biggest impact
of the Air War was the way that the German Army was unable to move
during daylight at all. Yes the bomber streams to deep german
targets had a lot to do with reducing the Luftwaffe to impotance
so the actual damage due to bombs droped became of little importance.
This was just as well since the Post War studies showed that the
Miltary impact of bomb damage had been very little until late 44
when decision to concentrate on oil was made. (Opps I should have
said Stratergic bombing, the Tactical bombing of bridges, trains
and other military point targets was also important.) In fact
Train Busting Sweeps were very effective in destroying the German
Armies ability to fight, These were done by cannon armed fighters
and fighter bomber versions.
>Corky Scott
Charles K. Scott
ste...@unipalm.co.uk (Steven Vincent) writes:
> Noway was it an unarmed
> mosquito squadron that first bombed Berlin in daylight AND timed
> that raid with a speach by Goring saying that the RAF could never
> bomb Berlin. The real hit here was that the sound of the Air Raid
> sirens followed by the explosions of the bombs could be heard in
> the background of Goring's speach.
You must have missed my post about this raid. There were only three
Mosquitos per raid, they penetrated German airspace on the deck and
popped up to 25,000 feet for a very brief bomb run then dove at maximum
speed back to the deck for egress. Three aircraft do not constitute a
mass formation.
Corky Scott
Peter N Croser
Kihlberg) wrote:
> > I remember reading somewhere that later Spitfire did/could have large
> > fuel tanks and, hance, could have been used for long range escort
> > instead of the Mustang. Is this true? If it is why weren't they used?
The long range fuel tank was primarily used by PR aircaft and special
long-range intrusion mission aircarft to get to Berlin etc. These were not
a standard fit in fighters.
>
> Some Spitfires had a extra fuel tank behind the pilot. It changed the
> balance of the plane and made it longitudially (spelling) unstable.
> The extra tank was used mainly for ferry flights.
These tanks weren't used for ferry purposes I believe, they were for
special long range Photo recon later marks of spitfire. The wings of later
Spitfires were "wet" or bagged and this increased range. The slipper tank
was fitted for ferrying and missions for fighters (not PR as much) and
also to get aircaft to Malta. These were steel, heavy and basic (I have a
90 gallon unit at home). The 90 gallon tank was used alot here in
Australia. The Spitfire 1 had 85 Gallons the Seafire 47 had 154 gallons
standard fit. The PR XIX had 84 gallons front 33 gallons rear tank, 2 wing
tanks 36 gallons and 2 combat tanks 45 gallons and drop tank 170
gallons...total 368 gallons but internal capacity 257 gallons.
--
Peter N Croser
David Murnain
>> I remember reading somewhere that later Spitfire did/could have large
>> fuel tanks and, hance, could have been used for long range escort
>> instead of the Mustang. Is this true? If it is why weren't they used?
This question keeps rising so often maybe it should be in a FAQ. Simply put
a mid-series mark (Mk VIII or IX, can't remember.) was fitted with a 75
gallon tank behind the pilot and a 45 gallon drop tank. It was then flown at
a height of 1000 feet for an equivalent distance of Berlin and back. The
rear tank caused lateral stability problems - just like in the Mustang when it's
rear tank was used - and it was never cleared for squadron service until the
late Mk 20+ series of Spitfires.
For the full story read 'Spitfire" by Jeffrey Quill. (He was Supermarine's
test pilot for most of the Spitfire development and explains it all very well.)
---------------------------------------------------------
David Murnain |What is good, and what
murn...@draken.itntl.bhp.com.au|is not good Phaedrus ?.
BHP Information Technology |Need we ask others to
Newcastle, Australia |tell us these things ?.
---------------------------------------------------------
Philip Morten
In article <1995Mar22.2...@cerberus.bhpese.oz.au>,
|>
|>>Robert Virding (r...@erix.ericsson.se) wrote:
|>>> I remember reading somewhere that later Spitfire did/could have
|>large
|>>> fuel tanks and, hance, could have been used for long range escort
|>>> instead of the Mustang. Is this true? If it is why weren't they
|>used?
|>
|>This question keeps rising so often maybe it should be in a FAQ.
|>Simply put
|>a mid-series mark (Mk VIII or IX, can't remember.) was fitted with a
|>75
|>gallon tank behind the pilot and a 45 gallon drop tank. It was then
|>flown at
|>a height of 1000 feet for an equivalent distance of Berlin and back.
|>The
|>rear tank caused lateral stability problems - just like in the Mustang
|>when it's
|>rear tank was used - and it was never cleared for squadron service
|>until the
|>late Mk 20+ series of Spitfires.
|>
As far as late Mk 20+ series aircraft was concerned the rear fuselage
tanks were fitted only to Mk.24 aircraft. The fuel system for these
aircraft is described in AP2816B & C - Pilot's Notes Spitfire 22 & 24,
Paragraph 2 of Part I says
"2. Fuel tanks.- Fuel is carried in six tanks, two main tanks
mounted one above the other in the fuselage and two interconnected
tanks in the leading edge of each wing. ...
...
A drop tank of 30, 45, 50 or 90 gallons capacity can be fitted under the
fuselage. ... "
Later it includes this table :
Top tank .............................. 36 gallons
Bottom Tank ........................... 48 gallons
2 wing tanks (12 1/2 gallons each) .... 25 gallons
2 wing tanks (5 1/2 gallons each) .... 11 gallons
---
Total .. .. .. .. .. .. 120 gallons
It then goes on to say (in a paragraph added by amendment)
"Mk.24 aircraft have rear fueslge tanks. They are in two sections
upper and lower, the capacity of each being 33 gallons."
Total internal fuel for the Mk.24 is therefore 186 gallons.
PART II - Handling has two pages on "Management of the fuel system"
describing the order in which the fuel tanks should be used.
In Para 45 General flying, sub-para (i) Stability , it says:
At high altitudes, with the rear fuselage tanks full, the aircraft
will not maintain trimmed flight with hands off the controls
and there is a tendency to tighten in turns. In this
condition the aircraft should be restricted to
gentle manoevres"